// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// This file defines functions that integrate Chrome in Windows shell. These
// functions can be used by Chrome as well as Chrome installer. All of the
// work is done by the local functions defined in anonymous namespace in
// this class.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "chrome/installer/util/shell_util.h"

#include <objbase.h>

#include <shobjidl.h>

#include <shellapi.h>
#include <shlobj.h>
#include <wrl/client.h>

#include <algorithm>
#include <iterator>
#include <limits>
#include <memory>
#include <string>
#include <utility>

#include "base/command_line.h"
#include "base/containers/span.h"
#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/functional/bind.h"
#include "base/hash/md5.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/strings/cstring_view.h"
#include "base/strings/strcat.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/synchronization/atomic_flag.h"
#include "base/values.h"
#include "base/win/default_apps_util.h"
#include "base/win/registry.h"
#include "base/win/scoped_co_mem.h"
#include "base/win/shortcut.h"
#include "base/win/win_util.h"
#include "base/win/windows_version.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/install_static/install_constants.h"
#include "chrome/install_static/install_details.h"
#include "chrome/install_static/install_modes.h"
#include "chrome/install_static/install_util.h"
#include "chrome/installer/util/beacons.h"
#include "chrome/installer/util/helper.h"
#include "chrome/installer/util/initial_preferences.h"
#include "chrome/installer/util/initial_preferences_constants.h"
#include "chrome/installer/util/install_util.h"
#include "chrome/installer/util/installer_util_strings.h"
#include "chrome/installer/util/l10n_string_util.h"
#include "chrome/installer/util/registry_entry.h"
#include "chrome/installer/util/registry_util.h"
#include "chrome/installer/util/taskbar_util.h"
#include "chrome/installer/util/util_constants.h"
#include "chrome/installer/util/work_item.h"
#include "components/base32/base32.h"
#include "third_party/abseil-cpp/absl/cleanup/cleanup.h"

using base::win::RegKey;

namespace {

// An enum used to tell QuickIsChromeRegistered() which level of registration
// the caller wants to confirm.
enum RegistrationConfirmationLevel {
  // Only look for Chrome's ProgIds.
  // This is sufficient when we are trying to determine the suffix of the
  // currently running Chrome as shell integration registrations might not be
  // present.
  CONFIRM_PROGID_REGISTRATION = 0,
  // Confirm that Chrome is fully integrated with Windows (i.e. registered with
  // Default Programs). These registrations can be in HKCU as of Windows 8.
  // Note: Shell registration implies ProgId registration.
  CONFIRM_SHELL_REGISTRATION,
  // Same as CONFIRM_SHELL_REGISTRATION, but only look in HKLM (used when
  // uninstalling to know whether elevation is required to clean up the
  // registry).
  CONFIRM_SHELL_REGISTRATION_IN_HKLM,
};

const wchar_t kReinstallCommand[] = L"ReinstallCommand";

const wchar_t kRegProgId[] = L"ProgId";

const wchar_t kFilePathSeparator[] = L"\\";

const wchar_t kFileHandlerProgIds[] = L"FileHandlerProgIds";

const wchar_t kFileExtensions[] = L"FileExtensions";

// ProgIds cannot be longer than 39 characters.
// Ref: http://msdn.microsoft.com/en-us/library/aa911706.aspx.
// Make all new registrations comply with this requirement (existing
// registrations must be preserved).
std::wstring LegalizeNewProgId(std::wstring prog_id,
                               const std::wstring suffix) {
  std::wstring new_style_suffix;
  if (ShellUtil::GetUserSpecificRegistrySuffix(&new_style_suffix) &&
      suffix == new_style_suffix && prog_id.length() > 39) {
    NOTREACHED();
  }
  return prog_id;
}

// Returns the current (or installed) browser's ProgId (e.g.
// "ChromeHTML|suffix|").
// `suffix` can be the empty string.
std::wstring GetBrowserProgId(const std::wstring& suffix) {
  return LegalizeNewProgId(
      base::StrCat({install_static::GetBrowserProgIdPrefix(), suffix}), suffix);
}

// Returns the current (or installed) PDF viewer's ProgId (e.g.
// "ChromePDF|suffix|").
// `suffix` can be the empty string.
std::wstring GetPDFProgId(const std::wstring& suffix) {
  return LegalizeNewProgId(
      base::StrCat({install_static::GetPDFProgIdPrefix(), suffix}), suffix);
}

// Returns the browser's application name. This application name will be
// suffixed as is appropriate for the current install. This is the name that is
// registered with Default Programs on Windows and that should thus be used to
// "make chrome default" and such.
std::wstring GetApplicationName(const base::FilePath& chrome_exe) {
  return base::StrCat({install_static::GetBaseAppName(),
                       ShellUtil::GetCurrentInstallationSuffix(chrome_exe)});
}

// This class is used to initialize and cache a base 32 encoding of the md5 hash
// of this user's sid preceded by a dot.
// This is guaranteed to be unique on the machine and 27 characters long
// (including the '.').
// This is then meant to be used as a suffix on all registrations that may
// conflict with another user-level Chrome install.
class UserSpecificRegistrySuffix {
 public:
  // All the initialization is done in the constructor to be able to build the
  // suffix in a thread-safe manner when used in conjunction with a
  // LazyInstance.
  UserSpecificRegistrySuffix();

  UserSpecificRegistrySuffix(const UserSpecificRegistrySuffix&) = delete;
  UserSpecificRegistrySuffix& operator=(const UserSpecificRegistrySuffix&) =
      delete;

  // Sets |suffix| to the pre-computed suffix cached in this object.
  // Returns true unless the initialization originally failed.
  bool GetSuffix(std::wstring* suffix);

 private:
  std::wstring suffix_;
};  // class UserSpecificRegistrySuffix

UserSpecificRegistrySuffix::UserSpecificRegistrySuffix() {
  std::wstring user_sid;
  if (!base::win::GetUserSidString(&user_sid)) {
    NOTREACHED();
  }
  static_assert(sizeof(base::MD5Digest) == 16, "size of MD5 not as expected");
  base::MD5Digest md5_digest;
  std::string user_sid_ascii(base::WideToASCII(user_sid));
  base::MD5Sum(base::as_byte_span(user_sid_ascii), &md5_digest);
  std::string base32_md5 = base32::Base32Encode(
      md5_digest.a, base32::Base32EncodePolicy::OMIT_PADDING);
  // The value returned by the base32 algorithm above must never change.
  DCHECK_EQ(base32_md5.length(), 26U);
  suffix_.reserve(base32_md5.length() + 1);
  suffix_.assign(1, L'.');
  suffix_ += base::ASCIIToWide(base32_md5);
}

bool UserSpecificRegistrySuffix::GetSuffix(std::wstring* suffix) {
  if (suffix_.empty()) {
    NOTREACHED();
  }
  suffix->assign(suffix_);
  return true;
}

// Returns the Windows browser client registration key for Chrome.  For example:
// "Software\Clients\StartMenuInternet\Chromium[.user]".  Strictly speaking, we
// should use the name of the executable (e.g., "chrome.exe"), but that ship has
// sailed.  The cost of switching now is re-prompting users to make Chrome their
// default browser, which isn't polite.  |suffix| is the user-specific
// registration suffix; see GetUserSpecificDefaultBrowserSuffix in shell_util.h
// for details.
std::wstring GetBrowserClientKey(const std::wstring& suffix) {
  DCHECK(suffix.empty() || suffix[0] == L'.');
  return base::StrCat({std::wstring(ShellUtil::kRegStartMenuInternet),
                       kFilePathSeparator, install_static::GetBaseAppName(),
                       suffix});
}

// Returns the Windows Default Programs capabilities key for Chrome.  For
// example:
// "Software\Clients\StartMenuInternet\Chromium[.user]\Capabilities".
std::wstring GetCapabilitiesKey(const std::wstring& suffix) {
  return base::StrCat({GetBrowserClientKey(suffix), L"\\Capabilities"});
}

// DelegateExecute ProgId. Needed for Chrome Metro in Windows 8. This is only
// needed for registering a web browser, not for general associations.
std::vector<std::unique_ptr<RegistryEntry>> GetChromeDelegateExecuteEntries(
    const base::FilePath& chrome_exe,
    const ShellUtil::ApplicationInfo& app_info) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;

  std::wstring app_id_shell_key =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, app_info.app_id,
                    ShellUtil::kRegExePath, ShellUtil::kRegShellPath});

  // <root hkey>\Software\Classes\<app_id>\.exe\shell @=open
  entries.push_back(std::make_unique<RegistryEntry>(app_id_shell_key,
                                                    ShellUtil::kRegVerbOpen));

  // The command to execute when opening this application via the Metro UI.
  const std::wstring delegate_command(
      ShellUtil::GetChromeDelegateCommand(chrome_exe));

  // Each of Chrome's shortcuts has an appid; which, as of Windows 8, is
  // registered to handle some verbs. This registration has the side-effect
  // that these verbs now show up in the shortcut's context menu. We
  // mitigate this side-effect by making the context menu entries
  // user readable/localized strings. See relevant MSDN article:
  // http://msdn.microsoft.com/en-US/library/windows/desktop/cc144171.aspx
  static const struct {
    const wchar_t* verb;
    int name_id;
  } verbs[] = {
      {ShellUtil::kRegVerbOpen, -1},
      {ShellUtil::kRegVerbOpenNewWindow, IDS_SHORTCUT_NEW_WINDOW_BASE},
  };
  for (const auto& verb_and_id : verbs) {
    std::wstring sub_path =
        base::StrCat({app_id_shell_key, kFilePathSeparator, verb_and_id.verb});

    // <root hkey>\Software\Classes\<app_id>\.exe\shell\<verb>
    if (verb_and_id.name_id != -1) {
      // TODO(grt): http://crbug.com/75152 Write a reference to a localized
      // resource.
      const std::wstring verb_name(
          installer::GetLocalizedString(verb_and_id.name_id));
      entries.push_back(
          std::make_unique<RegistryEntry>(sub_path, verb_name.c_str()));
    }
    entries.push_back(std::make_unique<RegistryEntry>(sub_path, L"CommandId",
                                                      L"Browser.Launch"));

    base::StrAppend(&sub_path, {kFilePathSeparator, ShellUtil::kRegCommand});

    // <root hkey>\Software\Classes\<app_id>\.exe\shell\<verb>\command
    entries.push_back(
        std::make_unique<RegistryEntry>(sub_path, delegate_command));
    entries.push_back(std::make_unique<RegistryEntry>(
        sub_path, ShellUtil::kRegDelegateExecute, app_info.delegate_clsid));
  }

  return entries;
}

// Gets the registry entries to register an application in the Windows registry.
// |app_info| provides all of the information needed.
void GetProgIdEntries(const ShellUtil::ApplicationInfo& app_info,
                      std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  // Basic sanity checks.
  DCHECK(!app_info.prog_id.empty());
  DCHECK_NE(L'.', app_info.prog_id[0]);

  // File association ProgId
  std::wstring prog_id_path = base::StrCat(
      {ShellUtil::kRegClasses, kFilePathSeparator, app_info.prog_id});
  entries->push_back(
      std::make_unique<RegistryEntry>(prog_id_path, app_info.file_type_name));
  entries->push_back(std::make_unique<RegistryEntry>(
      prog_id_path + ShellUtil::kRegDefaultIcon,
      ShellUtil::FormatIconLocation(app_info.file_type_icon_path,
                                    app_info.file_type_icon_index)));
  entries->push_back(std::make_unique<RegistryEntry>(
      prog_id_path + ShellUtil::kRegShellOpen, app_info.command_line));
  if (!app_info.delegate_clsid.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        prog_id_path + ShellUtil::kRegShellOpen, ShellUtil::kRegDelegateExecute,
        app_info.delegate_clsid));
    // TODO(scottmg): Simplify after Metro removal. https://crbug.com/558054.
    entries->back()->set_removal_flag(RegistryEntry::RemovalFlag::VALUE);
  }

  // The following entries are required but do not depend on the DelegateExecute
  // verb handler being set.
  if (!app_info.app_id.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        prog_id_path, ShellUtil::kRegAppUserModelId, app_info.app_id));
  }

  // Add \Software\Classes\<prog_id>\Application entries
  std::wstring application_path(prog_id_path + ShellUtil::kRegApplication);
  if (!app_info.app_id.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        application_path, ShellUtil::kRegAppUserModelId, app_info.app_id));
  }
  if (!app_info.application_icon_path.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        application_path, ShellUtil::kRegApplicationIcon,
        ShellUtil::FormatIconLocation(app_info.application_icon_path,
                                      app_info.application_icon_index)));
  }
  if (!app_info.application_name.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        application_path, ShellUtil::kRegApplicationName,
        app_info.application_name));
  }
  if (!app_info.application_description.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        application_path, ShellUtil::kRegApplicationDescription,
        app_info.application_description));
  }
  if (!app_info.publisher_name.empty()) {
    entries->push_back(std::make_unique<RegistryEntry>(
        application_path, ShellUtil::kRegApplicationCompany,
        app_info.publisher_name));
  }
}

// This method returns a list of all the registry entries that are needed to
// register this installation's ProgIds and AppId.
void GetChromeProgIdEntries(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  const int chrome_icon_index = install_static::GetAppIconResourceIndex();

  ShellUtil::ApplicationInfo app_info;
  app_info.prog_id = GetBrowserProgId(suffix);
  app_info.file_type_name = install_static::GetBrowserProgIdDescription();
  app_info.file_type_icon_path = chrome_exe;
  // File types associated with Chrome are given the Chrome html icon, except
  // for PDF files, which are given a Chrome PDF icon.
  app_info.file_type_icon_index = install_static::GetHTMLIconResourceIndex();
  app_info.command_line = ShellUtil::GetChromeShellOpenCmd(chrome_exe);
  // For user-level installs: entries for the app id will be in HKCU; thus we
  // do not need a suffix on those entries.
  app_info.app_id =
      ShellUtil::GetBrowserModelId(InstallUtil::IsPerUserInstall());

  // TODO(grt): http://crbug.com/75152 Write a reference to a localized
  // resource for name, description, and company.
  app_info.application_name = InstallUtil::GetDisplayName();
  app_info.application_icon_path = chrome_exe;
  app_info.application_icon_index = chrome_icon_index;
  app_info.application_description = InstallUtil::GetAppDescription();
  app_info.publisher_name = InstallUtil::GetPublisherName();
  app_info.delegate_clsid = install_static::GetLegacyCommandExecuteImplClsid();

  GetProgIdEntries(app_info, entries);

  // Get ProgId entries for PDF documents.
  app_info.prog_id = GetPDFProgId(suffix);
  app_info.file_type_name = install_static::GetPDFProgIdDescription();
  app_info.file_type_icon_index = install_static ::GetPDFIconResourceIndex();
  app_info.application_icon_index = chrome_icon_index;
  GetProgIdEntries(app_info, entries);

  if (!app_info.delegate_clsid.empty()) {
    auto delegate_execute_entries =
        GetChromeDelegateExecuteEntries(chrome_exe, app_info);
    // Remove the keys (not only their values) so that Windows will continue
    // to launch Chrome without a pesky association error.
    // TODO(scottmg): Simplify after Metro removal. https://crbug.com/558054.
    for (const auto& entry : delegate_execute_entries)
      entry->set_removal_flag(RegistryEntry::RemovalFlag::KEY);
    // Move |delegate_execute_entries| to |entries|.
    std::move(delegate_execute_entries.begin(), delegate_execute_entries.end(),
              std::back_inserter(*entries));
  }
}

// This method returns a list of the registry entries needed to declare a
// capability of handling protocol associations on Windows.
void GetProtocolCapabilityEntries(
    const std::wstring& suffix,
    const ShellUtil::ProtocolAssociations& protocol_associations,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  for (const auto& association : protocol_associations.associations) {
    entries->push_back(std::make_unique<RegistryEntry>(
        base::StrCat({GetCapabilitiesKey(suffix), L"\\URLAssociations"}),
        association.first, association.second));
  }
}

// This method returns a list of the registry entries required to register this
// installation in "RegisteredApplications" on Windows (to appear in Default
// Programs, StartMenuInternet, etc.). If `suffix` is not empty, these entries
// are guaranteed to be unique on this machine.
void GetShellIntegrationEntries(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  const std::wstring icon_path(ShellUtil::FormatIconLocation(
      chrome_exe, install_static::GetAppIconResourceIndex()));
  const std::wstring quoted_exe_path(L"\"" + chrome_exe.value() + L"\"");

  // Register for the Start Menu "Internet" link (pre-Win7).
  const std::wstring start_menu_entry(GetBrowserClientKey(suffix));
  // Register Chrome's display name.
  // TODO(grt): http://crbug.com/75152 Also set LocalizedString; see
  // http://msdn.microsoft.com/en-us/library/windows/desktop/cc144109(v=VS.85).aspx#registering_the_display_name
  entries->push_back(std::make_unique<RegistryEntry>(
      start_menu_entry, InstallUtil::GetDisplayName()));
  // Register the "open" verb for launching Chrome via the "Internet" link.
  entries->push_back(std::make_unique<RegistryEntry>(
      start_menu_entry + ShellUtil::kRegShellOpen, quoted_exe_path));
  // Register Chrome's icon for the Start Menu "Internet" link.
  entries->push_back(std::make_unique<RegistryEntry>(
      start_menu_entry + ShellUtil::kRegDefaultIcon, icon_path));

  // Register installation information.
  std::wstring install_info(start_menu_entry + L"\\InstallInfo");
  // Note: not using CommandLine since it has ambiguous rules for quoting
  // strings.
  entries->push_back(std::make_unique<RegistryEntry>(
      install_info, kReinstallCommand,
      quoted_exe_path + L" --" +
          base::ASCIIToWide(switches::kMakeDefaultBrowser)));
  entries->push_back(std::make_unique<RegistryEntry>(
      install_info, L"HideIconsCommand",
      quoted_exe_path + L" --" + base::ASCIIToWide(switches::kHideIcons)));
  entries->push_back(std::make_unique<RegistryEntry>(
      install_info, L"ShowIconsCommand",
      quoted_exe_path + L" --" + base::ASCIIToWide(switches::kShowIcons)));
  entries->push_back(
      std::make_unique<RegistryEntry>(install_info, L"IconsVisible", 1));

  // Register with Default Programs.
  const std::wstring reg_app_name =
      base::StrCat({install_static::GetBaseAppName(), suffix});
  // Tell Windows where to find Chrome's Default Programs info.
  const std::wstring capabilities(GetCapabilitiesKey(suffix));
  entries->push_back(std::make_unique<RegistryEntry>(
      ShellUtil::kRegRegisteredApplications, reg_app_name, capabilities));
  // Write out Chrome's Default Programs info.
  // TODO(grt): http://crbug.com/75152 Write a reference to a localized
  // resource rather than this.
  entries->push_back(std::make_unique<RegistryEntry>(
      capabilities, ShellUtil::kRegApplicationDescription,
      InstallUtil::GetLongAppDescription()));
  entries->push_back(std::make_unique<RegistryEntry>(
      capabilities, ShellUtil::kRegApplicationIcon, icon_path));
  entries->push_back(std::make_unique<RegistryEntry>(
      capabilities, ShellUtil::kRegApplicationName,
      InstallUtil::GetDisplayName()));

  entries->push_back(std::make_unique<RegistryEntry>(
      capabilities + L"\\Startmenu", L"StartMenuInternet", reg_app_name));

  const std::wstring html_prog_id(GetBrowserProgId(suffix));
  // Register HTML and PDF Prog IDs (e.g., ChromePDF) with the corresponding
  // file association.
  for (int i = 0; ShellUtil::kPotentialFileAssociations[i] != nullptr; i++) {
    entries->push_back(std::make_unique<RegistryEntry>(
        capabilities + L"\\FileAssociations",
        ShellUtil::kPotentialFileAssociations[i],
        wcscmp(ShellUtil::kPotentialFileAssociations[i], L".pdf") == 0
            ? GetPDFProgId(suffix)
            : html_prog_id));
  }
  for (int i = 0; ShellUtil::kPotentialProtocolAssociations[i] != nullptr;
       i++) {
    entries->push_back(std::make_unique<RegistryEntry>(
        capabilities + L"\\URLAssociations",
        ShellUtil::kPotentialProtocolAssociations[i], html_prog_id));
  }
}

// Gets the registry entries to register an application as a handler for a
// particular file extension. |prog_id| is the ProgId used by Windows for the
// application. |ext| is the file extension, which must begin with a '.'.
void GetAppExtRegistrationEntries(
    const std::wstring& prog_id,
    const std::wstring& ext,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  // In HKEY_CURRENT_USER\Software\Classes\EXT\OpenWithProgids, create an
  // empty value with this class's ProgId.
  std::wstring key_name =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, ext,
                    kFilePathSeparator, ShellUtil::kRegOpenWithProgids});
  entries->push_back(
      std::make_unique<RegistryEntry>(key_name, prog_id, std::wstring()));
}

// This method returns a list of the registry entries required for this
// installation to be registered in the Windows shell.
// In particular:
//  - App Paths
//    http://msdn.microsoft.com/en-us/library/windows/desktop/ee872121
//  - File Associations
//    http://msdn.microsoft.com/en-us/library/bb166549
// These entries need to be registered in HKLM prior to Win8.
void GetChromeAppRegistrationEntries(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  std::wstring app_path_key =
      base::StrCat({ShellUtil::kAppPathsRegistryKey, kFilePathSeparator,
                    chrome_exe.BaseName().value()});
  entries->push_back(
      std::make_unique<RegistryEntry>(app_path_key, chrome_exe.value()));
  entries->push_back(std::make_unique<RegistryEntry>(
      app_path_key, ShellUtil::kAppPathsRegistryPathName,
      chrome_exe.DirName().value()));

  const std::wstring html_prog_id(GetBrowserProgId(suffix));
  for (int i = 0; ShellUtil::kPotentialFileAssociations[i] != nullptr; i++) {
    GetAppExtRegistrationEntries(
        html_prog_id, ShellUtil::kPotentialFileAssociations[i], entries);
  }
}

// Gets the registry entries to register an application as the default handler
// for a particular file extension. |prog_id| is the ProgId used by Windows for
// the application. |ext| is the file extension, which must begin with a '.'. If
// |overwrite_existing|, always sets the default handler; otherwise only sets if
// there is no existing default.
//
// This has no effect on Windows 8. Windows 8 ignores the default and lets the
// user choose. If there is only one handler for a file, it will automatically
// become the default. Otherwise, the first time the user opens a file, they are
// presented with the dialog to set the default handler. (This is roughly
// equivalent to being called with |overwrite_existing| false.)
void GetAppDefaultRegistrationEntries(
    const std::wstring& prog_id,
    const std::wstring& ext,
    bool overwrite_existing,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  // Set the default value of HKEY_CURRENT_USER\Software\Classes\EXT to this
  // class's name.
  std::wstring key_name =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, ext});
  auto default_association = std::make_unique<RegistryEntry>(key_name, prog_id);
  if (overwrite_existing ||
      !default_association->KeyExistsInRegistry(RegistryEntry::LOOK_IN_HKCU)) {
    entries->push_back(std::move(default_association));
  }
}

// This method returns a list of all the user level registry entries that are
// needed to make Chromium the default handler for a protocol on XP.
void GetXPStyleUserProtocolEntries(
    const std::wstring& protocol,
    const std::wstring& chrome_icon,
    const std::wstring& chrome_open,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  // Protocols associations.
  std::wstring url_key =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, protocol});

  // This registry value tells Windows that this 'class' is a URL scheme
  // so IE, explorer and other apps will route it to our handler.
  // <root hkey>\Software\Classes\<protocol>\URL Protocol
  entries->push_back(std::make_unique<RegistryEntry>(
      url_key, ShellUtil::kRegUrlProtocol, std::wstring()));

  // <root hkey>\Software\Classes\<protocol>\DefaultIcon
  std::wstring icon_key = url_key + ShellUtil::kRegDefaultIcon;
  entries->push_back(std::make_unique<RegistryEntry>(icon_key, chrome_icon));

  // <root hkey>\Software\Classes\<protocol>\shell\open\command
  std::wstring shell_key = url_key + ShellUtil::kRegShellOpen;
  entries->push_back(std::make_unique<RegistryEntry>(shell_key, chrome_open));

  // <root hkey>\Software\Classes\<protocol>\shell\open\ddeexec
  std::wstring dde_key = url_key + L"\\shell\\open\\ddeexec";
  entries->push_back(std::make_unique<RegistryEntry>(dde_key, std::wstring()));

  // <root hkey>\Software\Classes\<protocol>\shell\@
  std::wstring protocol_shell_key = url_key + ShellUtil::kRegShellPath;
  entries->push_back(
      std::make_unique<RegistryEntry>(protocol_shell_key, L"open"));
}

// This method returns a list of all the user level registry entries that are
// needed to make Chromium default browser on XP. Some of these entries are
// irrelevant in recent versions of Windows, but we register them anyways as
// some legacy apps are hardcoded to lookup those values.
void GetXPStyleDefaultBrowserUserEntries(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    std::vector<std::unique_ptr<RegistryEntry>>* entries) {
  // File extension associations.
  std::wstring html_prog_id(GetBrowserProgId(suffix));
  for (int i = 0; ShellUtil::kDefaultFileAssociations[i] != nullptr; i++) {
    GetAppDefaultRegistrationEntries(
        html_prog_id, ShellUtil::kDefaultFileAssociations[i], true, entries);
  }

  // Protocols associations.
  std::wstring chrome_open = ShellUtil::GetChromeShellOpenCmd(chrome_exe);
  std::wstring chrome_icon = ShellUtil::FormatIconLocation(
      chrome_exe, install_static::GetAppIconResourceIndex());
  for (int i = 0; ShellUtil::kBrowserProtocolAssociations[i] != nullptr; i++) {
    GetXPStyleUserProtocolEntries(ShellUtil::kBrowserProtocolAssociations[i],
                                  chrome_icon, chrome_open, entries);
  }

  // start->Internet shortcut.
  std::wstring start_menu(ShellUtil::kRegStartMenuInternet);
  std::wstring app_name =
      base::StrCat({install_static::GetBaseAppName(), suffix});
  entries->push_back(std::make_unique<RegistryEntry>(start_menu, app_name));
}

// Checks that all |entries| are present on this computer (or absent if their
// |removal_flag_| is set). |look_for_in| is passed to
// RegistryEntry::ExistsInRegistry(). Documentation for it can be found there.
bool AreEntriesAsDesired(
    const std::vector<std::unique_ptr<RegistryEntry>>& entries,
    uint32_t look_for_in) {
  for (const auto& entry : entries) {
    if (entry->ExistsInRegistry(look_for_in) != !entry->IsFlaggedForRemoval())
      return false;
  }
  return true;
}

// Checks that all required registry entries for Chrome are already present on
// this computer (or absent if their |removal_flag_| is set).
// See RegistryEntry::ExistsInRegistry for the behavior of |look_for_in|.
// Note: between r133333 and r154145 we were registering parts of Chrome in HKCU
// and parts in HKLM for user-level installs; we now always register everything
// under a single registry root. Not doing so caused http://crbug.com/144910 for
// users who first-installed Chrome in that revision range (those users are
// still impacted by http://crbug.com/144910). This method will keep returning
// true for affected users (i.e. who have all the registrations, but over both
// registry roots).
bool IsChromeRegistered(const base::FilePath& chrome_exe,
                        const std::wstring& suffix,
                        uint32_t look_for_in) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  GetChromeProgIdEntries(chrome_exe, suffix, &entries);
  GetShellIntegrationEntries(chrome_exe, suffix, &entries);
  GetChromeAppRegistrationEntries(chrome_exe, suffix, &entries);
  return AreEntriesAsDesired(entries, look_for_in);
}

// This method checks if Chrome is already registered on the local machine
// for the requested protocol associations. It just checks the one value
// required for each association. See RegistryEntry::ExistsInRegistry for the
// behavior of |look_for_in|.
bool IsChromeRegisteredForProtocolAssociations(
    const std::wstring& suffix,
    const ShellUtil::ProtocolAssociations& protocol_associations,
    uint32_t look_for_in) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  GetProtocolCapabilityEntries(suffix, protocol_associations, &entries);
  return AreEntriesAsDesired(entries, look_for_in);
}

// This method registers Chrome by launching an elevated setup.exe. That will
// show the user the standard elevation prompt. If the user accepts it the new
// process will make the necessary changes and return SUCCESS that we capture
// and return. If |additional_switches| is non-null, setup.exe will be launched
// with the additional command line args. This is used for general browser
// registration on Windows 7 for per-user installs where setup.exe did not have
// permission to register Chrome during install. It may also be used on Windows
// 7 for system-level installs to register Chrome for specific protocol
// associations (via |additional_switches|).
bool ElevateAndRegisterChrome(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    const base::CommandLine::SwitchMap* additional_switches) {
  // Check for setup.exe in the same directory as chrome.exe, as is the case
  // when running out of a build output directory.
  base::FilePath exe_path = chrome_exe.DirName().Append(installer::kSetupExe);

  // Failing that, read the path to setup.exe from Chrome's ClientState key,
  // which is the canonical location of the installer for all types of installs
  // (see AddUninstallShortcutWorkItems).
  const bool is_per_user = InstallUtil::IsPerUserInstall();
  if (!base::PathExists(exe_path)) {
    RegKey key(is_per_user ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE,
               install_static::GetClientStateKeyPath().c_str(),
               KEY_QUERY_VALUE | KEY_WOW64_32KEY);
    std::wstring uninstall_string;
    if (key.ReadValue(installer::kUninstallStringField, &uninstall_string) ==
        ERROR_SUCCESS) {
      exe_path = base::FilePath(uninstall_string);
    }
  }

  if (base::PathExists(exe_path)) {
    base::CommandLine cmd(exe_path);
    InstallUtil::AppendModeAndChannelSwitches(&cmd);
    if (!is_per_user)
      cmd.AppendSwitch(installer::switches::kSystemLevel);
    cmd.AppendSwitchPath(installer::switches::kRegisterChromeBrowser,
                         chrome_exe);
    if (!suffix.empty()) {
      cmd.AppendSwitchNative(installer::switches::kRegisterChromeBrowserSuffix,
                             suffix);
    }

    if (additional_switches) {
      for (const auto& switch_pair : *additional_switches)
        cmd.AppendSwitchNative(switch_pair.first, switch_pair.second);
    }

    DWORD ret_val = 0;
    InstallUtil::ExecuteExeAsAdmin(cmd, &ret_val);
    if (ret_val == 0)
      return true;
  }
  return false;
}

// Returns true if |chrome_exe| has been registered with |suffix| for |mode|.
// |confirmation_level| is the level of verification desired as described in
// the RegistrationConfirmationLevel enum above.
// |suffix| can be the empty string (this is used to support old installs
// where we used to not suffix user-level installs if they were the first to
// request the non-suffixed registry entries on the machine).
// NOTE: This a quick check that only validates that a single registry entry
// points to |chrome_exe|. This should only be used at run-time to determine
// how Chrome is registered, not to know whether the registration is complete
// at install-time (IsChromeRegistered() can be used for that).
bool QuickIsChromeRegisteredForMode(
    const base::FilePath& chrome_exe,
    const std::wstring& suffix,
    const install_static::InstallConstants& mode,
    RegistrationConfirmationLevel confirmation_level) {
  // Get the appropriate key to look for based on the level desired.
  std::wstring reg_key;
  switch (confirmation_level) {
    case CONFIRM_PROGID_REGISTRATION:
      // Software\Classes\ChromeHTML|suffix|
      reg_key = base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator,
                              mode.browser_prog_id_prefix, suffix});
      break;
    case CONFIRM_SHELL_REGISTRATION:
    case CONFIRM_SHELL_REGISTRATION_IN_HKLM:
      // Software\Clients\StartMenuInternet\Google Chrome|suffix|
      reg_key = GetBrowserClientKey(suffix);
      break;
    default:
      NOTREACHED();
  }
  reg_key += ShellUtil::kRegShellOpen;

  // ProgId and shell integration registrations are allowed to reside in HKCU
  // for user-level installs, and values there have priority over values in
  // HKLM.
  if (confirmation_level == CONFIRM_PROGID_REGISTRATION ||
      confirmation_level == CONFIRM_SHELL_REGISTRATION) {
    const RegKey key_hkcu(HKEY_CURRENT_USER, reg_key.c_str(), KEY_QUERY_VALUE);
    std::wstring hkcu_value;
    // If |reg_key| is present in HKCU, assert that it points to |chrome_exe|.
    // Otherwise, fall back on an HKLM lookup below.
    if (key_hkcu.ReadValue(L"", &hkcu_value) == ERROR_SUCCESS)
      return installer::ProgramCompare(chrome_exe).Evaluate(hkcu_value);
  }

  // Assert that |reg_key| points to |chrome_exe| in HKLM.
  const RegKey key_hklm(HKEY_LOCAL_MACHINE, reg_key.c_str(), KEY_QUERY_VALUE);
  std::wstring hklm_value;
  if (key_hklm.ReadValue(L"", &hklm_value) == ERROR_SUCCESS)
    return installer::ProgramCompare(chrome_exe).Evaluate(hklm_value);
  return false;
}

// Returns true if the current install's |chrome_exe| has been registered with
// |suffix|.
// |confirmation_level| is the level of verification desired as described in
// the RegistrationConfirmationLevel enum above.
// |suffix| can be the empty string (this is used to support old installs
// where we used to not suffix user-level installs if they were the first to
// request the non-suffixed registry entries on the machine).
// NOTE: This a quick check that only validates that a single registry entry
// points to |chrome_exe|. This should only be used at run-time to determine
// how Chrome is registered, not to know whether the registration is complete
// at install-time (IsChromeRegistered() can be used for that).
bool QuickIsChromeRegistered(const base::FilePath& chrome_exe,
                             const std::wstring& suffix,
                             RegistrationConfirmationLevel confirmation_level) {
  return QuickIsChromeRegisteredForMode(
      chrome_exe, suffix, install_static::InstallDetails::Get().mode(),
      confirmation_level);
}

// Sets |suffix| to a 27 character string that is specific to this user on this
// machine (on user-level installs only).
// To support old-style user-level installs however, |suffix| is cleared if the
// user currently owns the non-suffixed HKLM registrations.
// |suffix| can also be set to the user's username if the current install is
// suffixed as per the old-style registrations.
// |suffix| is cleared on system-level installs.
// |suffix| should then be appended to all Chrome properties that may conflict
// with other Chrome user-level installs.
// Returns true unless one of the underlying calls fails.
bool GetInstallationSpecificSuffix(const base::FilePath& chrome_exe,
                                   std::wstring* suffix) {
  if (!InstallUtil::IsPerUserInstall() ||
      QuickIsChromeRegistered(chrome_exe, std::wstring(),
                              CONFIRM_SHELL_REGISTRATION)) {
    // No suffix on system-level installs and user-level installs already
    // registered with no suffix.
    suffix->clear();
    return true;
  }

  // Get the old suffix for the check below.
  if (!ShellUtil::GetOldUserSpecificRegistrySuffix(suffix)) {
    NOTREACHED();
  }
  if (QuickIsChromeRegistered(chrome_exe, *suffix,
                              CONFIRM_SHELL_REGISTRATION)) {
    // Username suffix for installs that are suffixed as per the old-style.
    return true;
  }

  return ShellUtil::GetUserSpecificRegistrySuffix(suffix);
}

// Returns the root registry key (HKLM or HKCU) under which registrations must
// be placed for this install. As of Windows 8 everything can go in HKCU for
// per-user installs.
HKEY DetermineRegistrationRoot(bool is_per_user) {
  return is_per_user ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE;
}

// Associates Chrome with supported protocols and file associations. This should
// not be required on Vista+ but since some applications still read
// Software\Classes\http key directly, we have to do this on Vista+ as well.
bool RegisterChromeAsDefaultXPStyle(int shell_change,
                                    const base::FilePath& chrome_exe) {
  bool ret = true;
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  GetXPStyleDefaultBrowserUserEntries(
      chrome_exe, ShellUtil::GetCurrentInstallationSuffix(chrome_exe),
      &entries);

  // Change the default browser for current user.
  if ((shell_change & ShellUtil::CURRENT_USER) &&
      !ShellUtil::AddRegistryEntries(HKEY_CURRENT_USER, entries)) {
    ret = false;
    LOG(ERROR) << "Could not make Chrome default browser (XP/current user).";
  }

  // Chrome as default browser at system level.
  if ((shell_change & ShellUtil::SYSTEM_LEVEL) &&
      !ShellUtil::AddRegistryEntries(HKEY_LOCAL_MACHINE, entries)) {
    ret = false;
    LOG(ERROR) << "Could not make Chrome default browser (XP/system level).";
  }

  return ret;
}

// Associates Chrome with |protocol| in the registry. This should not be
// required on Vista+ but since some applications still read these registry
// keys directly, we have to do this on Vista+ as well.
// See http://msdn.microsoft.com/library/aa767914.aspx for more details.
bool RegisterChromeAsDefaultProtocolClientXPStyle(
    const base::FilePath& chrome_exe,
    const std::wstring& protocol) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  const std::wstring chrome_open(ShellUtil::GetChromeShellOpenCmd(chrome_exe));
  const std::wstring chrome_icon(ShellUtil::FormatIconLocation(
      chrome_exe, install_static::GetAppIconResourceIndex()));
  GetXPStyleUserProtocolEntries(protocol, chrome_icon, chrome_open, &entries);
  // Change the default protocol handler for current user.
  if (!ShellUtil::AddRegistryEntries(HKEY_CURRENT_USER, entries)) {
    LOG(ERROR) << "Could not make Chrome default protocol client (XP).";
    return false;
  }

  return true;
}

// Returns |properties.shortcut_name| if the property is set, otherwise it
// returns InstallUtil::GetShortcutName(). In any case, it makes sure the return
// value is suffixed with ".lnk".
std::wstring ExtractShortcutNameFromProperties(
    const ShellUtil::ShortcutProperties& properties) {
  std::wstring shortcut_name = properties.has_shortcut_name()
                                   ? properties.shortcut_name
                                   : InstallUtil::GetShortcutName();

  if (!base::EndsWith(shortcut_name, installer::kLnkExt,
                      base::CompareCase::INSENSITIVE_ASCII))
    shortcut_name += installer::kLnkExt;

  return shortcut_name;
}

// Converts ShellUtil::ShortcutOperation to the best-matching value in
// base::win::ShortcutOperation.
base::win::ShortcutOperation TranslateShortcutOperation(
    ShellUtil::ShortcutOperation operation) {
  switch (operation) {
    case ShellUtil::SHELL_SHORTCUT_CREATE_ALWAYS:  // Falls through.
    case ShellUtil::SHELL_SHORTCUT_CREATE_IF_NO_SYSTEM_LEVEL:
      return base::win::ShortcutOperation::kCreateAlways;

    case ShellUtil::SHELL_SHORTCUT_UPDATE_EXISTING:
      return base::win::ShortcutOperation::kUpdateExisting;

    case ShellUtil::SHELL_SHORTCUT_REPLACE_EXISTING:
      return base::win::ShortcutOperation::kReplaceExisting;

    default:
      NOTREACHED();
  }
}

// Returns a base::win::ShortcutProperties struct containing the properties
// to set on the shortcut based on the provided ShellUtil::ShortcutProperties.
base::win::ShortcutProperties TranslateShortcutProperties(
    const ShellUtil::ShortcutProperties& properties) {
  base::win::ShortcutProperties shortcut_properties;

  if (properties.has_target()) {
    shortcut_properties.set_target(properties.target);
    DCHECK(!properties.target.DirName().empty());
    shortcut_properties.set_working_dir(properties.target.DirName());
  }

  if (properties.has_arguments())
    shortcut_properties.set_arguments(properties.arguments);

  if (properties.has_description())
    shortcut_properties.set_description(properties.description);

  if (properties.has_icon())
    shortcut_properties.set_icon(properties.icon, properties.icon_index);

  if (properties.has_app_id())
    shortcut_properties.set_app_id(properties.app_id);

  if (properties.has_toast_activator_clsid()) {
    shortcut_properties.set_toast_activator_clsid(
        properties.toast_activator_clsid);
  }

  return shortcut_properties;
}

// Cleans up an old verb (run) we used to register in
// <root>\Software\Classes\Chrome<.suffix>\.exe\shell\run on Windows 8.
void RemoveRunVerbOnWindows8() {
  bool is_per_user_install = InstallUtil::IsPerUserInstall();
  HKEY root_key = DetermineRegistrationRoot(is_per_user_install);
  // There's no need to rollback, so forgo the usual work item lists and just
  // remove the key from the registry.
  std::wstring run_verb_key =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator,
                    ShellUtil::GetBrowserModelId(is_per_user_install),
                    ShellUtil::kRegExePath, ShellUtil::kRegShellPath,
                    kFilePathSeparator, ShellUtil::kRegVerbRun});
  installer::DeleteRegistryKey(root_key, run_verb_key, WorkItem::kWow64Default);
}

// Probes default handler registration (in a manner appropriate for the current
// version of Windows) to determine if Chrome is the default handler for
// `identifiers`. `identifiers` can be either protocols or file extensions, and
// `type` should indicate which they are. Returns `IS_DEFAULT` only if Chrome is
// the default for all specified identifiers.
ShellUtil::DefaultState ProbeCurrentDefaultHandlers(
    const base::FilePath& chrome_exe,
    base::span<const base::wcstring_view> identifiers,
    ASSOCIATIONTYPE type) {
#if DCHECK_IS_ON()
  DCHECK(!identifiers.empty());
  for (const auto& identifier : identifiers) {
    DCHECK(!identifier.empty());
    if (type == AT_FILEEXTENSION) {
      DCHECK(identifier.starts_with(base::FilePath::kExtensionSeparator));
    }
  }
#endif
  Microsoft::WRL::ComPtr<IApplicationAssociationRegistration> registration;
  HRESULT hr = ::SHCreateAssociationRegistration(IID_PPV_ARGS(&registration));
  if (FAILED(hr))
    return ShellUtil::UNKNOWN_DEFAULT;

  // Get the ProgID for the current install mode.
  std::wstring prog_id =
      base::StrCat({install_static::GetBrowserProgIdPrefix(),
                    ShellUtil::GetCurrentInstallationSuffix(chrome_exe)});

  const int current_install_mode_index =
      install_static::InstallDetails::Get().install_mode_index();
  bool other_mode_is_default = false;
  for (const auto& identifier : identifiers) {
    base::win::ScopedCoMem<wchar_t> current_app;
    // Probe using `IApplicationAssociationRegistration::QueryCurrentDefault`.
    // This mechanism is not suitable for use on versions of Windows older than
    // Windows 8 despite the presence of `QueryCurrentDefault` on them, as those
    // versions did not perform validation on the ProgID registered as the
    // current default. As a result, stale ProgIDs could be returned, leading to
    // false positives.
    hr = registration->QueryCurrentDefault(identifier.c_str(), type,
                                           AL_EFFECTIVE, &current_app);
    if (FAILED(hr))
      return ShellUtil::NOT_DEFAULT;
    if (prog_id.compare(current_app) == 0)
      continue;

    // See if another mode is the default handler for this identifier.
    size_t current_app_len = std::char_traits<wchar_t>::length(current_app);
    const auto it = std::ranges::find_if(
        install_static::kInstallModes,
        [current_install_mode_index, &current_app,
         current_app_len](const install_static::InstallConstants& mode) {
          if (mode.index == current_install_mode_index) {
            return false;
          }
          const std::wstring mode_prog_id_prefix(mode.browser_prog_id_prefix);
          // Does the current app either match this mode's ProgID or contain
          // this mode's ProgID as a prefix followed by the '.' separator for a
          // per-user install's suffix?
          if (!base::StartsWith(current_app.get(), mode_prog_id_prefix,
                                base::CompareCase::SENSITIVE)) {
            return false;
          }
          return current_app_len == mode_prog_id_prefix.length() ||
                 current_app[mode_prog_id_prefix.length()] == L'.';
        });
    if (it == install_static::kInstallModes.end()) {
      return ShellUtil::NOT_DEFAULT;
    }
    other_mode_is_default = true;
  }
  // This mode is default if it has all of the identifiers.
  return other_mode_is_default ? ShellUtil::OTHER_MODE_IS_DEFAULT
                               : ShellUtil::IS_DEFAULT;
}

// Helper function to call `ProbeCurrentDefaultHandlers()` with a single
// `identifier`.
ShellUtil::DefaultState ProbeSingleCurrentDefaultHandler(
    base::wcstring_view identifier,
    ASSOCIATIONTYPE type) {
  if (identifier.empty()) {
    return ShellUtil::UNKNOWN_DEFAULT;
  }
  return ProbeCurrentDefaultHandlers(
      base::PathService::CheckedGet(base::FILE_EXE), {identifier}, type);
}

// Finds and stores an app shortcuts folder path in *`path`.
// Returns true on success.
bool GetAppShortcutsFolder(ShellUtil::ShellChange level, base::FilePath* path) {
  DCHECK(path);

  base::FilePath folder;
  if (!base::PathService::Get(base::DIR_APP_SHORTCUTS, &folder)) {
    LOG(ERROR) << "Could not get application shortcuts location.";
    return false;
  }

  folder = folder.Append(
      ShellUtil::GetBrowserModelId(level == ShellUtil::CURRENT_USER));
  if (!base::DirectoryExists(folder)) {
    VLOG(1) << "No start screen shortcuts.";
    return false;
  }

  *path = folder;
  return true;
}

// Shortcut filters for BatchShortcutAction().

using ShortcutFilterCallback =
    base::RepeatingCallback<bool(const base::FilePath& shortcut_path,
                                 const std::wstring& args)>;

// FilterTargetContains is a shortcut filter that matches shortcuts that target
// any of a set of candidate files, and optionally matches shortcuts that have
// non-empty arguments.
class FilterTargetContains {
 public:
  FilterTargetContains(const std::vector<base::FilePath>& target_paths,
                       bool require_args);

  // Returns true if filter rules are satisfied, i.e.:
  // - |target_path|'s target == |desired_target_compare_|, and
  // - |args| is non-empty (if |require_args_| == true).
  bool Match(const base::FilePath& target_path, const std::wstring& args) const;

  // A convenience routine to create a callback to call Match().
  // The callback is only valid during the lifetime of the FilterTargetEq
  // instance.
  ShortcutFilterCallback AsShortcutFilterCallback();

 private:
  std::vector<installer::ProgramCompare> desired_target_compare_;
  bool require_args_;
};

FilterTargetContains::FilterTargetContains(
    const std::vector<base::FilePath>& target_paths,
    bool require_args)
    : desired_target_compare_(std::begin(target_paths), std::end(target_paths)),
      require_args_(require_args) {}

bool FilterTargetContains::Match(const base::FilePath& target_path,
                                 const std::wstring& args) const {
  if (std::ranges::none_of(desired_target_compare_,
                           [&target_path](const auto& target_compare) {
                             return target_compare.EvaluatePath(target_path);
                           })) {
    return false;
  }
  if (require_args_ && args.empty())
    return false;
  return true;
}

ShortcutFilterCallback FilterTargetContains::AsShortcutFilterCallback() {
  return base::BindRepeating(&FilterTargetContains::Match,
                             base::Unretained(this));
}

// Shortcut operations for BatchShortcutAction().

using ShortcutOperationCallback =
    base::RepeatingCallback<bool(const base::FilePath& shortcut_path)>;

bool ShortcutOpUnpinFromTaskbar(const base::FilePath& shortcut_path) {
  VLOG(1) << "Trying to unpin from taskbar " << shortcut_path.value();
  if (!UnpinShortcutFromTaskbar(shortcut_path)) {
    VLOG(1) << shortcut_path.value()
            << " wasn't pinned to taskbar (or the unpin failed).";
    // No error, since shortcut might not be pinned.
  }
  return true;
}

bool ShortcutOpDelete(const base::FilePath& shortcut_path) {
  bool ret = base::DeleteFile(shortcut_path);
  PLOG_IF(ERROR, !ret) << "Failed to remove " << shortcut_path.value();
  return ret;
}

bool ShortcutOpRetarget(const base::FilePath& old_target,
                        const base::FilePath& new_target,
                        const base::FilePath& shortcut_path) {
  base::win::ShortcutProperties new_prop;
  new_prop.set_target(new_target);

  // If the old icon matches old target, then update icon while keeping the old
  // icon index. Non-fatal if we fail to get the old icon.
  base::win::ShortcutProperties old_prop;
  if (base::win::ResolveShortcutProperties(
          shortcut_path, base::win::ShortcutProperties::PROPERTIES_ICON,
          &old_prop)) {
    if (installer::ProgramCompare(old_target).EvaluatePath(old_prop.icon))
      new_prop.set_icon(new_target, old_prop.icon_index);
  } else {
    LOG(ERROR) << "Failed to resolve " << shortcut_path.value();
  }

  bool result = base::win::CreateOrUpdateShortcutLink(
      shortcut_path, new_prop, base::win::ShortcutOperation::kUpdateExisting);
  LOG_IF(ERROR, !result) << "Failed to retarget " << shortcut_path.value();
  return result;
}

bool ShortcutOpListOrRemoveUnknownArgs(
    bool do_removal,
    std::vector<std::pair<base::FilePath, std::wstring>>* shortcuts,
    const base::FilePath& shortcut_path) {
  std::wstring args;
  if (!base::win::ResolveShortcut(shortcut_path, nullptr, &args))
    return false;

  base::CommandLine current_args(
      base::CommandLine::FromString(L"unused_program " + args));
  const char* const kept_switches[] = {
      switches::kApp,
      switches::kAppId,
      switches::kProfileDirectory,
  };
  base::CommandLine desired_args(base::CommandLine::NO_PROGRAM);
  desired_args.CopySwitchesFrom(current_args, kept_switches);
  if (desired_args.argv().size() == current_args.argv().size())
    return true;
  if (shortcuts)
    shortcuts->push_back(std::make_pair(shortcut_path, args));
  if (!do_removal)
    return true;
  base::win::ShortcutProperties updated_properties;
  updated_properties.set_arguments(desired_args.GetArgumentsString());
  return base::win::CreateOrUpdateShortcutLink(
      shortcut_path, updated_properties,
      base::win::ShortcutOperation::kUpdateExisting);
}

bool ShortcutOpResetAttributes(const base::FilePath& file_path) {
  const DWORD kAllowedAttributes =
      FILE_ATTRIBUTE_ARCHIVE | FILE_ATTRIBUTE_REPARSE_POINT;
  DWORD attributes = ::GetFileAttributes(file_path.value().c_str());
  if (attributes == INVALID_FILE_ATTRIBUTES)
    return false;
  if ((attributes & (~kAllowedAttributes)) == 0)
    return true;
  return ::SetFileAttributes(file_path.value().c_str(),
                             attributes & kAllowedAttributes);
}

// {|location|, |level|} determine |shortcut_folder|.
// For each shortcut in |shortcut_folder| that match |shortcut_filter|, apply
// |shortcut_operation|. Returns true if all operations are successful.
// All intended operations are attempted, even if failures occur.
// This method will abort and return false if |cancel| is non-nullptr and gets
// set at any point during this call.
bool BatchShortcutAction(
    const ShortcutFilterCallback& shortcut_filter,
    const ShortcutOperationCallback& shortcut_operation,
    ShellUtil::ShortcutLocation location,
    ShellUtil::ShellChange level,
    const scoped_refptr<ShellUtil::SharedCancellationFlag>& cancel) {
  DCHECK(!shortcut_operation.is_null());

  // There is no system-level Quick Launch shortcut folder.
  if (level == ShellUtil::SYSTEM_LEVEL &&
      location == ShellUtil::SHORTCUT_LOCATION_QUICK_LAUNCH) {
    return true;
  }

  base::FilePath shortcut_folder;
  if (!ShellUtil::GetShortcutPath(location, level, &shortcut_folder)) {
    LOG(WARNING) << "Cannot find path at location " << location;
    return false;
  }

  bool success = true;
  base::FileEnumerator enumerator(shortcut_folder, false,
                                  base::FileEnumerator::FILES,
                                  std::wstring(L"*") + installer::kLnkExt);
  base::FilePath target_path;
  std::wstring args;
  for (base::FilePath shortcut_path = enumerator.Next(); !shortcut_path.empty();
       shortcut_path = enumerator.Next()) {
    if (cancel.get() && cancel->data.IsSet())
      return false;
    if (base::win::ResolveShortcut(shortcut_path, &target_path, &args)) {
      if (shortcut_filter.Run(target_path, args) &&
          !shortcut_operation.Run(shortcut_path)) {
        success = false;
      }
    } else {
      LOG(ERROR) << "Cannot resolve shortcut at " << shortcut_path.value();
      success = false;
    }
  }
  return success;
}

// If the folder specified by {|location|, |level|} is empty, remove it.
// Otherwise do nothing. Returns true on success, including the vacuous case
// where no deletion occurred because directory is non-empty.
bool RemoveShortcutFolderIfEmpty(ShellUtil::ShortcutLocation location,
                                 ShellUtil::ShellChange level) {
  // Explicitly allow locations, since accidental calls can be very harmful.
  if (location !=
          ShellUtil::SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED &&
      location != ShellUtil::SHORTCUT_LOCATION_START_MENU_CHROME_APPS_DIR &&
      location != ShellUtil::SHORTCUT_LOCATION_APP_SHORTCUTS) {
    NOTREACHED();
  }

  base::FilePath shortcut_folder;
  if (!ShellUtil::GetShortcutPath(location, level, &shortcut_folder)) {
    LOG(WARNING) << "Cannot find path at location " << location;
    return false;
  }
  if (base::IsDirectoryEmpty(shortcut_folder) &&
      !base::DeletePathRecursively(shortcut_folder)) {
    LOG(ERROR) << "Cannot remove folder " << shortcut_folder.value();
    return false;
  }
  return true;
}

// Return a shortened version of |component|. Cut in the middle to try
// to avoid losing the unique parts of |component| (which are usually
// at the beginning or end for things like usernames and paths).
std::wstring ShortenAppModelIdComponent(const std::wstring& component,
                                        int desired_length) {
  return component.substr(0, desired_length / 2) +
         component.substr(component.length() - ((desired_length + 1) / 2));
}

// Gets the registry entry which stores the default handler for |protocol|.
std::unique_ptr<RegistryEntry> GetProtocolUserChoiceEntry(
    const std::wstring& protocol) {
  std::wstring user_choice_path = base::StrCat(
      {L"SOFTWARE\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\",
       protocol, L"\\UserChoice"});
  return std::make_unique<RegistryEntry>(user_choice_path.c_str(), kRegProgId);
}

// Gets a ProtocolAssociations instance containing a single association where
// |protocol| is handled by the default HTML browser handler.
ShellUtil::ProtocolAssociations GetBrowserProtocolAssociation(
    const std::wstring& protocol,
    const base::FilePath& chrome_exe) {
  ShellUtil::ProtocolAssociations protocol_associations;
  std::wstring suffix;
  if (!GetInstallationSpecificSuffix(chrome_exe, &suffix))
    return protocol_associations;

  std::wstring browser_progid = GetBrowserProgId(suffix);
  if (browser_progid.empty())
    return protocol_associations;

  protocol_associations.associations.emplace(protocol,
                                             std::move(browser_progid));
  return protocol_associations;
}

bool RegisterChromeBrowserImpl(const base::FilePath& chrome_exe,
                               const std::wstring& unique_suffix,
                               bool elevate_if_not_admin,
                               bool best_effort_no_rollback) {
  base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();

  std::wstring suffix;
  if (!unique_suffix.empty()) {
    suffix = unique_suffix;
  } else if (command_line.HasSwitch(
                 installer::switches::kRegisterChromeBrowserSuffix)) {
    suffix = command_line.GetSwitchValueNative(
        installer::switches::kRegisterChromeBrowserSuffix);
  } else if (!GetInstallationSpecificSuffix(chrome_exe, &suffix)) {
    return false;
  }

  RemoveRunVerbOnWindows8();

  bool user_level = InstallUtil::IsPerUserInstall();
  HKEY root = DetermineRegistrationRoot(user_level);

  // Look only in HKLM for system-level installs (otherwise, if a user-level
  // install is also present, it will lead IsChromeRegistered() to think this
  // system-level install isn't registered properly as it is shadowed by the
  // user-level install's registrations).
  uint32_t look_for_in = user_level ? RegistryEntry::LOOK_IN_HKCU_THEN_HKLM
                                    : RegistryEntry::LOOK_IN_HKLM;

  // Check if chrome is already registered with this suffix.
  if (IsChromeRegistered(chrome_exe, suffix, look_for_in))
    return true;

  // Ensure that the shell is notified of the mutations below. Specific exit
  // points may disable this if no mutations are made.
  absl::Cleanup notify_on_exit = [] {
    SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nullptr, nullptr);
  };

  // Do the full registration at user-level or if the user is an admin.
  if (root == HKEY_CURRENT_USER || IsUserAnAdmin()) {
    std::vector<std::unique_ptr<RegistryEntry>> progid_and_appreg_entries;
    std::vector<std::unique_ptr<RegistryEntry>> shell_entries;
    GetChromeProgIdEntries(chrome_exe, suffix, &progid_and_appreg_entries);
    GetChromeAppRegistrationEntries(chrome_exe, suffix,
                                    &progid_and_appreg_entries);
    GetShellIntegrationEntries(chrome_exe, suffix, &shell_entries);
    const std::wstring html_prog_id = GetBrowserProgId(suffix);
    return ShellUtil::AddRegistryEntries(root, progid_and_appreg_entries,
                                         best_effort_no_rollback) &&
           ShellUtil::AddRegistryEntries(root, shell_entries,
                                         best_effort_no_rollback);
  }
  // The installer is responsible for registration for system-level installs, so
  // never try to do it here. Getting to this point for a system-level install
  // likely means that IsChromeRegistered thinks registration is broken due to
  // localization issues (see https://crbug.com/717913#c18). It likely is not,
  // so return success to allow Chrome to be made default.
  if (!user_level) {
    std::move(notify_on_exit).Cancel();
    return true;
  }
  // Try to elevate and register if requested for per-user installs if the user
  // is not an admin.
  if (elevate_if_not_admin &&
      ElevateAndRegisterChrome(chrome_exe, suffix, nullptr)) {
    return true;
  }
  // If we got to this point then all we can do is create ProgId and basic app
  // registrations under HKCU.
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  GetChromeProgIdEntries(chrome_exe, std::wstring(), &entries);
  // Prefer to use |suffix|; unless Chrome's ProgIds are already registered with
  // no suffix (as per the old registration style): in which case some other
  // registry entries could refer to them and since we were not able to set our
  // HKLM entries above, we are better off not altering these here.
  if (!AreEntriesAsDesired(entries, RegistryEntry::LOOK_IN_HKCU)) {
    if (!suffix.empty()) {
      entries.clear();
      GetChromeProgIdEntries(chrome_exe, suffix, &entries);
      GetChromeAppRegistrationEntries(chrome_exe, suffix, &entries);
    }
    return ShellUtil::AddRegistryEntries(HKEY_CURRENT_USER, entries,
                                         best_effort_no_rollback);
  }
  // The ProgId is registered unsuffixed in HKCU, also register the app with
  // Windows in HKCU (this was not done in the old registration style and thus
  // needs to be done after the above check for the unsuffixed registration).
  entries.clear();
  GetChromeAppRegistrationEntries(chrome_exe, std::wstring(), &entries);
  return ShellUtil::AddRegistryEntries(HKEY_CURRENT_USER, entries,
                                       best_effort_no_rollback);
}

// Registers a set of protocols for a particular application in the Windows
// registry.
//
// This method is not supported and should not be called in Windows versions
// prior to Win8, where write access to HKLM is required.
//
// |protocols| is the set of protocols to register. Must not be empty.
// |prog_id| is the ProgId used by Windows for protocol associations with this
// application. Must not be empty or start with a '.'.
// |chrome_exe|: the full path to chrome.exe.
bool RegisterApplicationForProtocols(const std::vector<std::wstring>& protocols,
                                     const std::wstring& prog_id,
                                     const base::FilePath& chrome_exe) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;
  ShellUtil::ApplicationInfo app_info =
      ShellUtil::GetApplicationInfoForProgId(prog_id);

  // Build the Windows Default Programs capabilities key for the app.
  // "HKEY_CURRENT_USER\Software\[CompanyPathName\]ProductPathName[install_suffix]\AppProtocolHandlers\|prog_id|\Capabilities".
  std::wstring capabilities_path = base::StrCat(
      {install_static::GetRegistryPath(), ShellUtil::kRegAppProtocolHandlers,
       kFilePathSeparator, prog_id, L"\\Capabilities"});

  entries.push_back(std::make_unique<RegistryEntry>(
      capabilities_path, ShellUtil::kRegApplicationName,
      app_info.application_name));

  // Use name as app description if description from |prog_id| registration is
  // empty.
  std::wstring app_description = app_info.application_description.empty()
                                     ? app_info.application_name
                                     : app_info.application_description;
  entries.push_back(std::make_unique<RegistryEntry>(
      capabilities_path, ShellUtil::kRegApplicationDescription,
      app_description));

  // Create URLAssociations
  const std::wstring url_associations =
      base::StrCat({std::wstring(capabilities_path), L"\\URLAssociations"});

  for (const auto& protocol : protocols) {
    entries.push_back(
        std::make_unique<RegistryEntry>(url_associations, protocol, prog_id));
  }

  // Add the |prog_id| value to HKEY_CURRENT_USER\RegisteredApplications.
  entries.push_back(std::make_unique<RegistryEntry>(
      ShellUtil::kRegRegisteredApplications, prog_id, capabilities_path));

  return AreEntriesAsDesired(entries, RegistryEntry::LOOK_IN_HKCU) ||
         ShellUtil::AddRegistryEntries(HKEY_CURRENT_USER, entries);
}

bool DeleteFileExtensionsForProgId(const std::wstring& prog_id) {
  const std::wstring prog_id_path =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, prog_id});

  // Get list of handled file extensions from value FileExtensions at
  // HKEY_CURRENT_USER\Software\Classes\|prog_id|.
  RegKey file_extensions_key(HKEY_CURRENT_USER, prog_id_path.c_str(),
                             KEY_QUERY_VALUE);
  std::wstring handled_file_extensions;
  if (file_extensions_key.ReadValue(
          kFileExtensions, &handled_file_extensions) == ERROR_SUCCESS) {
    const std::vector<std::wstring> file_extensions =
        base::SplitString(handled_file_extensions, std::wstring(L";"),
                          base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);

    // Delete file-extension-handling registry entries for each file extension.
    for (const auto& file_extension : file_extensions) {
      std::wstring extension_path = base::StrCat(
          {ShellUtil::kRegClasses, kFilePathSeparator, file_extension});

      // Delete value |prog_id| at
      // HKEY_CURRENT_USER\Software\Classes\.<extension>\OpenWithProgids;
      // this removes |prog_id| from the list of handlers for |file_extension|.
      base::StrAppend(&extension_path,
                      {kFilePathSeparator, ShellUtil::kRegOpenWithProgids});
      installer::DeleteRegistryValue(HKEY_CURRENT_USER, extension_path,
                                     WorkItem::kWow64Default, prog_id);

      // Note: if |prog_id| is later reinstalled with fewer extensions, it may
      // still appear in the Open With menu for extensions that it previously
      // handled due to cached entries in the most-recently-used list. These
      // entries can't be cleaned up by apps, so this is an unavoidable quirk
      // of Windows. See crbug.com/1177401 for details.
    }
  }
  // Delete the key HKEY_CURRENT_USER\Software\Classes\|prog_id|.
  return ShellUtil::DeleteApplicationClass(prog_id);
}

}  // namespace

const wchar_t* ShellUtil::kRegAppProtocolHandlers = L"\\AppProtocolHandlers";
const wchar_t* ShellUtil::kRegDefaultIcon = L"\\DefaultIcon";
const wchar_t* ShellUtil::kRegShellPath = L"\\shell";
const wchar_t* ShellUtil::kRegShellOpen = L"\\shell\\open\\command";
const wchar_t* ShellUtil::kRegSoftware = L"Software\\";
const wchar_t* ShellUtil::kRegStartMenuInternet =
    L"Software\\Clients\\StartMenuInternet";
const wchar_t* ShellUtil::kRegClasses = L"Software\\Classes";
const wchar_t* ShellUtil::kRegRegisteredApplications =
    L"Software\\RegisteredApplications";
const wchar_t* ShellUtil::kRegVistaUrlPrefs =
    L"Software\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\"
    L"http\\UserChoice";
const wchar_t* ShellUtil::kAppPathsRegistryKey =
    L"Software\\Microsoft\\Windows\\CurrentVersion\\App Paths";
const wchar_t* ShellUtil::kAppPathsRegistryPathName = L"Path";

const wchar_t* ShellUtil::kDefaultFileAssociations[] = {
    L".htm", L".html", L".shtml", L".xht", L".xhtml", nullptr};
const wchar_t* ShellUtil::kPotentialFileAssociations[] = {
    L".htm", L".html", L".mhtml", L".pdf",  L".shtml",
    L".svg", L".xht",  L".xhtml", L".webp", nullptr};
const wchar_t* ShellUtil::kBrowserProtocolAssociations[] = {L"http", L"https",
                                                            nullptr};
const wchar_t* ShellUtil::kPotentialProtocolAssociations[] = {
    L"http", L"https", L"irc",   L"mailto", L"mms", L"news",   L"nntp",
    L"sms",  L"smsto", L"snews", L"tel",    L"urn", L"webcal", nullptr};
const wchar_t* ShellUtil::kRegUrlProtocol = L"URL Protocol";
const wchar_t* ShellUtil::kRegApplication = L"\\Application";
const wchar_t* ShellUtil::kRegAppUserModelId = L"AppUserModelId";
const wchar_t* ShellUtil::kRegApplicationDescription =
    L"ApplicationDescription";
const wchar_t* ShellUtil::kRegApplicationName = L"ApplicationName";
const wchar_t* ShellUtil::kRegApplicationIcon = L"ApplicationIcon";
const wchar_t* ShellUtil::kRegApplicationCompany = L"ApplicationCompany";
const wchar_t* ShellUtil::kRegExePath = L"\\.exe";
const wchar_t* ShellUtil::kRegVerbOpen = L"open";
const wchar_t* ShellUtil::kRegVerbOpenNewWindow = L"opennewwindow";
const wchar_t* ShellUtil::kRegVerbRun = L"run";
const wchar_t* ShellUtil::kRegCommand = L"command";
const wchar_t* ShellUtil::kRegDelegateExecute = L"DelegateExecute";
const wchar_t* ShellUtil::kRegOpenWithProgids = L"OpenWithProgids";

ShellUtil::ShortcutProperties::ShortcutProperties(ShellChange level_in)
    : level(level_in), icon_index(0), pin_to_taskbar(false), options(0U) {}

ShellUtil::ShortcutProperties::ShortcutProperties(
    const ShortcutProperties& other) = default;

ShellUtil::ShortcutProperties::~ShortcutProperties() = default;

ShellUtil::ApplicationInfo::ApplicationInfo() = default;

ShellUtil::ApplicationInfo::ApplicationInfo(ApplicationInfo&& other) noexcept =
    default;

ShellUtil::ApplicationInfo::~ApplicationInfo() = default;

bool ShellUtil::QuickIsChromeRegisteredInHKLM(const base::FilePath& chrome_exe,
                                              const std::wstring& suffix) {
  return QuickIsChromeRegistered(chrome_exe, suffix,
                                 CONFIRM_SHELL_REGISTRATION_IN_HKLM);
}

bool ShellUtil::ShortcutLocationIsSupported(ShortcutLocation location) {
  switch (location) {
    case SHORTCUT_LOCATION_DESKTOP:                           // Falls through.
    case SHORTCUT_LOCATION_QUICK_LAUNCH:                      // Falls through.
    case SHORTCUT_LOCATION_START_MENU_ROOT:                   // Falls through.
    case SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED:  // Falls through.
    case SHORTCUT_LOCATION_START_MENU_CHROME_APPS_DIR:        // Falls through.
    case SHORTCUT_LOCATION_STARTUP:                           // Falls through.
    case SHORTCUT_LOCATION_TASKBAR_PINS:                      // Falls through.
    case SHORTCUT_LOCATION_APP_SHORTCUTS:
      return true;
    default:
      NOTREACHED();
  }
}

bool ShellUtil::GetShortcutPath(ShortcutLocation location,
                                ShellChange level,
                                base::FilePath* path) {
  DCHECK(path);
  int dir_key = -1;
  std::wstring folder_to_append;
  switch (location) {
    case SHORTCUT_LOCATION_DESKTOP:
      dir_key = (level == CURRENT_USER) ? int{base::DIR_USER_DESKTOP}
                                        : base::DIR_COMMON_DESKTOP;
      break;
    case SHORTCUT_LOCATION_QUICK_LAUNCH:
      // There is no support for a system-level Quick Launch shortcut.
      DCHECK_EQ(level, CURRENT_USER);
      dir_key = base::DIR_USER_QUICK_LAUNCH;
      break;
    case SHORTCUT_LOCATION_START_MENU_ROOT:
      dir_key = (level == CURRENT_USER) ? base::DIR_START_MENU
                                        : base::DIR_COMMON_START_MENU;
      break;
    case SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED:
      dir_key = (level == CURRENT_USER) ? base::DIR_START_MENU
                                        : base::DIR_COMMON_START_MENU;
      folder_to_append = InstallUtil::GetChromeShortcutDirNameDeprecated();
      break;
    case SHORTCUT_LOCATION_START_MENU_CHROME_APPS_DIR:
      dir_key = (level == CURRENT_USER) ? base::DIR_START_MENU
                                        : base::DIR_COMMON_START_MENU;
      folder_to_append = InstallUtil::GetChromeAppsShortcutDirName();
      break;
    case SHORTCUT_LOCATION_TASKBAR_PINS:
      dir_key = base::DIR_TASKBAR_PINS;
      break;
    case SHORTCUT_LOCATION_APP_SHORTCUTS:
      // TODO(huangs): Move GetAppShortcutsFolder() logic into base_paths_win.
      return GetAppShortcutsFolder(level, path);
    case SHORTCUT_LOCATION_STARTUP:
      dir_key = (level == CURRENT_USER) ? base::DIR_USER_STARTUP
                                        : base::DIR_COMMON_STARTUP;
      break;
  }

  if (!base::PathService::Get(dir_key, path) || path->empty())
    return false;

  if (!folder_to_append.empty())
    *path = path->Append(folder_to_append);

  return true;
}

// Modifies a ShortcutProperties object by adding default values to
// uninitialized members. Tries to assign:
// - target: |target_exe|.
// - icon: from |target_exe|.
// - icon_index: the browser's icon index
// - app_id: the browser model id for the current install.
// - description: the browser's app description.
// static
void ShellUtil::AddDefaultShortcutProperties(const base::FilePath& target_exe,
                                             ShortcutProperties* properties) {
  if (!properties->has_target())
    properties->set_target(target_exe);

  if (!properties->has_icon())
    properties->set_icon(target_exe, install_static::GetAppIconResourceIndex());

  if (!properties->has_app_id()) {
    properties->set_app_id(
        GetBrowserModelId(!install_static::IsSystemInstall()));
  }

  if (!properties->has_description())
    properties->set_description(InstallUtil::GetAppDescription());
}

bool ShellUtil::MoveExistingShortcut(ShortcutLocation old_location,
                                     ShortcutLocation new_location,
                                     const ShortcutProperties& properties) {
  // Explicitly allow locations to which this is applicable.
  if (old_location != SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED ||
      new_location != SHORTCUT_LOCATION_START_MENU_ROOT) {
    NOTREACHED();
  }

  std::wstring shortcut_name(ExtractShortcutNameFromProperties(properties));

  base::FilePath old_shortcut_path;
  base::FilePath new_shortcut_path;
  GetShortcutPath(old_location, properties.level, &old_shortcut_path);
  GetShortcutPath(new_location, properties.level, &new_shortcut_path);
  old_shortcut_path = old_shortcut_path.Append(shortcut_name);
  new_shortcut_path = new_shortcut_path.Append(shortcut_name);

  bool result = base::Move(old_shortcut_path, new_shortcut_path);
  RemoveShortcutFolderIfEmpty(old_location, properties.level);
  return result;
}

bool ShellUtil::TranslateShortcutCreationOrUpdateInfo(
    ShortcutLocation location,
    const ShortcutProperties& properties,
    ShortcutOperation operation,
    base::win::ShortcutOperation& base_operation,
    base::win::ShortcutProperties& base_properties,
    bool& should_install_shortcut,
    base::FilePath& shortcut_path) {
  // Explicitly allow locations to which this is applicable.
  if (location != SHORTCUT_LOCATION_DESKTOP &&
      location != SHORTCUT_LOCATION_QUICK_LAUNCH &&
      location != SHORTCUT_LOCATION_START_MENU_ROOT &&
      location != SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED &&
      location != SHORTCUT_LOCATION_START_MENU_CHROME_APPS_DIR) {
    DLOG(ERROR) << "Invalid shortcut location " << location;
    return false;
  }

  base::FilePath user_shortcut_path;
  base::FilePath system_shortcut_path;
  if (location == SHORTCUT_LOCATION_QUICK_LAUNCH) {
    // There is no system-level shortcut for Quick Launch.
    DCHECK_EQ(properties.level, CURRENT_USER);
  } else if (!GetShortcutPath(location, SYSTEM_LEVEL, &system_shortcut_path)) {
    DLOG(ERROR) << "Failed to get path for system-level shortcut at location "
                << location;
    return false;
  }

  std::wstring shortcut_name(ExtractShortcutNameFromProperties(properties));
  system_shortcut_path = system_shortcut_path.Append(shortcut_name);

  base::FilePath* chosen_path;
  should_install_shortcut = true;
  if (properties.level == SYSTEM_LEVEL) {
    // Install the system-level shortcut if requested.
    chosen_path = &system_shortcut_path;
  } else if (operation != SHELL_SHORTCUT_CREATE_IF_NO_SYSTEM_LEVEL ||
             system_shortcut_path.empty() ||
             !base::PathExists(system_shortcut_path)) {
    // Otherwise install the user-level shortcut, unless the system-level
    // variant of this shortcut is present on the machine and `operation` states
    // not to create a user-level shortcut in that case.
    if (!GetShortcutPath(location, CURRENT_USER, &user_shortcut_path)) {
      DLOG(ERROR) << "Failed to get path for user-level shortcut at location "
                  << location;
      return false;
    }
    user_shortcut_path = user_shortcut_path.Append(shortcut_name);
    chosen_path = &user_shortcut_path;
  } else {
    // Do not install any shortcut if we are told to install a user-level
    // shortcut, but the system-level variant of that shortcut is present.
    // Other actions (e.g., pinning) can still happen with respect to the
    // existing system-level shortcut however.
    chosen_path = &system_shortcut_path;
    should_install_shortcut = false;
  }

  base_operation = TranslateShortcutOperation(operation);
  base_properties = TranslateShortcutProperties(properties);
  shortcut_path = *chosen_path;

  return true;
}

bool ShellUtil::CreateOrUpdateShortcut(ShortcutLocation location,
                                       const ShortcutProperties& properties,
                                       ShortcutOperation operation,
                                       bool* pinned) {
  // |pin_to_taskbar| is only acknowledged when first creating the shortcut.
  DCHECK(!properties.pin_to_taskbar ||
         operation == SHELL_SHORTCUT_CREATE_ALWAYS ||
         operation == SHELL_SHORTCUT_CREATE_IF_NO_SYSTEM_LEVEL);

  base::win::ShortcutProperties shortcut_properties;
  base::win::ShortcutOperation shortcut_operation;
  base::FilePath shortcut_path;
  bool should_install_shortcut;
  if (!TranslateShortcutCreationOrUpdateInfo(
          location, properties, operation, shortcut_operation,
          shortcut_properties, should_install_shortcut, shortcut_path)) {
    return false;
  }
  if (should_install_shortcut &&
      !base::win::CreateOrUpdateShortcutLink(shortcut_path, shortcut_properties,
                                             shortcut_operation)) {
    return false;
  }

  if (shortcut_operation == base::win::ShortcutOperation::kCreateAlways &&
      properties.pin_to_taskbar && CanPinShortcutToTaskbar()) {
    bool pin_succeeded = PinShortcutToTaskbar(shortcut_path);
    LOG_IF(ERROR, !pin_succeeded)
        << "Failed to pin to taskbar " << shortcut_path.value();
    if (pinned)
      *pinned = pin_succeeded;
    if (pin_succeeded) {
      ::SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nullptr, nullptr);
    }
  }

  return true;
}

std::wstring ShellUtil::FormatIconLocation(const base::FilePath& icon_path,
                                           int icon_index) {
  return base::StrCat(
      {icon_path.value(), L",", base::NumberToWString(icon_index)});
}

std::optional<std::pair<base::FilePath, int>> ShellUtil::ParseIconLocation(
    const std::wstring& argument) {
  std::vector<std::wstring> icon_parts =
      base::SplitString(argument, std::wstring(L","), base::TRIM_WHITESPACE,
                        base::SPLIT_WANT_NONEMPTY);

  if (icon_parts.size() < 2)
    return std::nullopt;

  int icon_index = 0;
  base::StringToInt(icon_parts[1], &icon_index);

  return std::make_pair(base::FilePath(icon_parts[0]), icon_index);
}

std::wstring ShellUtil::GetChromeShellOpenCmd(
    const base::FilePath& chrome_exe) {
  return base::CommandLine(chrome_exe).GetCommandLineStringForShell();
}

std::wstring ShellUtil::GetChromeDelegateCommand(
    const base::FilePath& chrome_exe) {
  return L"\"" + chrome_exe.value() + L"\" -- %*";
}

void ShellUtil::GetRegisteredBrowsers(
    std::map<std::wstring, std::wstring>* browsers) {
  DCHECK(browsers);

  const std::wstring base_key(kRegStartMenuInternet);
  std::wstring client_path;
  RegKey key;
  std::wstring name;
  std::wstring command;

  // HKCU has precedence over HKLM for these registrations: http://goo.gl/xjczJ.
  // Look in HKCU second to override any identical values found in HKLM.
  const HKEY roots[] = {HKEY_LOCAL_MACHINE, HKEY_CURRENT_USER};
  for (const HKEY root : roots) {
    for (base::win::RegistryKeyIterator iter(root, base_key.c_str());
         iter.Valid(); ++iter) {
      client_path = base::StrCat({base_key, kFilePathSeparator, iter.Name()});
      // Read the browser's name (localized according to install language).
      if (key.Open(root, client_path.c_str(), KEY_QUERY_VALUE) !=
              ERROR_SUCCESS ||
          key.ReadValue(nullptr, &name) != ERROR_SUCCESS || name.empty() ||
          name.find(install_static::GetBaseAppName()) != std::wstring::npos) {
        continue;
      }
      // Read the browser's reinstall command.
      if (key.Open(root, (client_path + L"\\InstallInfo").c_str(),
                   KEY_QUERY_VALUE) == ERROR_SUCCESS &&
          key.ReadValue(kReinstallCommand, &command) == ERROR_SUCCESS &&
          !command.empty()) {
        (*browsers)[name] = command;
      }
    }
  }
}

std::wstring ShellUtil::GetCurrentInstallationSuffix(
    const base::FilePath& chrome_exe) {
  // This method is somewhat the opposite of GetInstallationSpecificSuffix().
  // In this case we are not trying to determine the current suffix for the
  // upcoming installation (i.e. not trying to stick to a currently bad
  // registration style if one is present).
  // Here we want to determine which suffix we should use at run-time.
  // In order of preference, we prefer (for user-level installs):
  //   1) Base 32 encoding of the md5 hash of the user's sid (new-style).
  //   2) Username (old-style).
  //   3) Unsuffixed (even worse).
  std::wstring tested_suffix;
  if (InstallUtil::IsPerUserInstall() &&
      (!GetUserSpecificRegistrySuffix(&tested_suffix) ||
       !QuickIsChromeRegistered(chrome_exe, tested_suffix,
                                CONFIRM_PROGID_REGISTRATION)) &&
      (!GetOldUserSpecificRegistrySuffix(&tested_suffix) ||
       !QuickIsChromeRegistered(chrome_exe, tested_suffix,
                                CONFIRM_PROGID_REGISTRATION)) &&
      !QuickIsChromeRegistered(chrome_exe, tested_suffix.erase(),
                               CONFIRM_PROGID_REGISTRATION)) {
    // If Chrome is not registered under any of the possible suffixes (e.g.
    // tests, Canary, etc.): use the new-style suffix at run-time.
    if (!GetUserSpecificRegistrySuffix(&tested_suffix)) {
      NOTREACHED();
    }
  }
  return tested_suffix;
}

std::wstring ShellUtil::GetBrowserModelId(bool is_per_user_install) {
  std::wstring app_id(install_static::GetBaseAppId());
  std::wstring suffix;

  // TODO(robertshield): Temporary hack to make the kRegisterChromeBrowserSuffix
  // apply to all registry values computed down in these murky depths.
  base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
  if (command_line.HasSwitch(
          installer::switches::kRegisterChromeBrowserSuffix)) {
    suffix = command_line.GetSwitchValueNative(
        installer::switches::kRegisterChromeBrowserSuffix);
  } else if (is_per_user_install && !GetUserSpecificRegistrySuffix(&suffix)) {
    NOTREACHED();
  }
  app_id += suffix;
  if (app_id.length() <= installer::kMaxAppModelIdLength)
    return app_id;
  return ShortenAppModelIdComponent(app_id, installer::kMaxAppModelIdLength);
}

std::wstring ShellUtil::BuildAppUserModelId(
    const std::vector<std::wstring>& components) {
  DCHECK_GT(components.size(), 0U);

  // Find the maximum numbers of characters allowed in each component
  // (accounting for the dots added between each component).
  const size_t available_chars =
      installer::kMaxAppModelIdLength - (components.size() - 1);
  const size_t max_component_length = available_chars / components.size();

  // |max_component_length| should be at least 2; otherwise the truncation logic
  // below breaks.
  if (max_component_length < 2U) {
    NOTREACHED();
  }

  std::wstring app_id;
  app_id.reserve(installer::kMaxAppModelIdLength);
  for (std::vector<std::wstring>::const_iterator it = components.begin();
       it != components.end(); ++it) {
    if (it != components.begin())
      app_id += L'.';

    const std::wstring& component = *it;
    DCHECK(!component.empty());
    if (component.length() > max_component_length) {
      app_id += ShortenAppModelIdComponent(component, max_component_length);
    } else {
      app_id += component;
    }
  }
  // No spaces are allowed in the AppUserModelId according to MSDN.
  base::ReplaceChars(app_id, L" ", L"_", &app_id);
  return app_id;
}

ShellUtil::DefaultState ShellUtil::GetChromeDefaultState() {
  base::FilePath app_path;
  if (!base::PathService::Get(base::FILE_EXE, &app_path)) {
    NOTREACHED();
  }

  return GetChromeDefaultStateFromPath(app_path);
}

ShellUtil::DefaultState ShellUtil::GetChromeDefaultStateFromPath(
    const base::FilePath& chrome_exe) {
  // When we check for default browser we don't necessarily want to count file
  // type handlers and icons as having changed the default browser status,
  // since the user may have changed their shell settings to cause HTML files
  // to open with a text editor for example. We also don't want to aggressively
  // claim FTP, since the user may have a separate FTP client. It is an open
  // question as to how to "heal" these settings. Perhaps the user should just
  // re-run the installer or run with the --set-default-browser command line
  // flag. There is doubtless some other key we can hook into to cause "Repair"
  // to show up in Add/Remove programs for us.
  static const base::wcstring_view kChromeProtocols[] = {L"http", L"https"};
  const DefaultState default_state =
      ProbeCurrentDefaultHandlers(chrome_exe, kChromeProtocols, AT_URLPROTOCOL);
  UpdateDefaultBrowserBeaconWithState(default_state);
  return default_state;
}

ShellUtil::DefaultState ShellUtil::GetChromeDefaultProtocolClientState(
    base::wcstring_view protocol) {
  return ProbeSingleCurrentDefaultHandler(protocol, AT_URLPROTOCOL);
}

ShellUtil::DefaultState ShellUtil::GetChromeDefaultFileHandlerState(
    base::wcstring_view file_extension) {
  DCHECK(file_extension.starts_with(base::FilePath::kExtensionSeparator));
  return ProbeSingleCurrentDefaultHandler(file_extension, AT_FILEEXTENSION);
}

// static
bool ShellUtil::CanMakeChromeDefaultUnattended() {
  return base::win::GetVersion() < base::win::Version::WIN8;
}

bool ShellUtil::MakeChromeDefault(int shell_change,
                                  const base::FilePath& chrome_exe,
                                  bool elevate_if_not_admin) {
  DCHECK(!(shell_change & SYSTEM_LEVEL) || IsUserAnAdmin());

  if (!install_static::SupportsSetAsDefaultBrowser())
    return false;

  // Windows 8 does not permit making a browser default just like that.
  // This process needs to be routed through the system's UI. Use
  // ShowMakeChromeDefaultSystemUI instead (below).
  if (!CanMakeChromeDefaultUnattended()) {
    return false;
  }

  if (!RegisterChromeBrowser(chrome_exe, std::wstring(),
                             elevate_if_not_admin)) {
    return false;
  }

  bool ret = true;
  // First use the new "recommended" way on Vista to make Chrome default
  // browser.
  std::wstring app_name = GetApplicationName(chrome_exe);

  // On Windows 7 we still can set ourselves via the the
  // IApplicationAssociationRegistration interface.
  VLOG(1) << "Registering Chrome as default browser on Windows 7.";
  Microsoft::WRL::ComPtr<IApplicationAssociationRegistration> pAAR;
  HRESULT hr = ::CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                  nullptr, CLSCTX_INPROC, IID_PPV_ARGS(&pAAR));
  if (SUCCEEDED(hr)) {
    for (int i = 0; kBrowserProtocolAssociations[i] != nullptr; i++) {
      hr = pAAR->SetAppAsDefault(
          app_name.c_str(), kBrowserProtocolAssociations[i], AT_URLPROTOCOL);
      if (!SUCCEEDED(hr)) {
        ret = false;
        LOG(ERROR) << "Failed to register as default for protocol "
                   << kBrowserProtocolAssociations[i] << " (" << hr << ")";
      }
    }

    for (int i = 0; kDefaultFileAssociations[i] != nullptr; i++) {
      hr = pAAR->SetAppAsDefault(app_name.c_str(), kDefaultFileAssociations[i],
                                 AT_FILEEXTENSION);
      if (!SUCCEEDED(hr)) {
        ret = false;
        LOG(ERROR) << "Failed to register as default for file extension "
                   << kDefaultFileAssociations[i] << " (" << hr << ")";
      }
    }
  }

  if (!RegisterChromeAsDefaultXPStyle(shell_change, chrome_exe))
    ret = false;

  // Send Windows notification event so that it can update icons for
  // file associations.
  SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nullptr, nullptr);
  return ret;
}

// static
bool ShellUtil::LaunchUninstallAppsSettings() {
  return base::win::LaunchSettingsUri(L"page=SettingsPageAppsSizes");
}

bool ShellUtil::ShowMakeChromeDefaultSystemUI(
    const base::FilePath& chrome_exe) {
  DCHECK(!CanMakeChromeDefaultUnattended());

  if (!install_static::SupportsSetAsDefaultBrowser())
    return false;

  if (!RegisterChromeBrowser(chrome_exe, std::wstring(), true))
    return false;

  bool succeeded = true;
  bool is_default = (GetChromeDefaultState() == IS_DEFAULT);
  bool is_win11_or_greater =
      base::win::GetVersion() >= base::win::Version::WIN11;
  if (!is_default) {
    if (is_win11_or_greater) {
      // Launch the Windows Apps Settings dialog and navigate to the settings
      // page for Chrome.
      succeeded = base::win::LaunchSettingsDefaultApps(
          GetApplicationName(chrome_exe), InstallUtil::IsPerUserInstall());
    }
    if (!is_win11_or_greater || !succeeded) {
      // Launch the Windows Apps Settings dialog.
      succeeded = base::win::LaunchDefaultAppsSettingsModernDialog(L"http");
    }
  }
  if (succeeded && is_default)
    RegisterChromeAsDefaultXPStyle(CURRENT_USER, chrome_exe);
  return succeeded;
}

bool ShellUtil::ShowSetDefaultForFileExtensionSystemUI(
    const base::FilePath& chrome_exe,
    base::wcstring_view file_extension,
    HWND parent_hwnd) {
  // Ensure `file_extension` is correctly formatted and is one of the extensions
  // Chrome handles.
  DCHECK(file_extension.starts_with(base::FilePath::kExtensionSeparator));
  DCHECK(std::ranges::any_of(base::span(ShellUtil::kPotentialFileAssociations),
                             [&file_extension](const wchar_t* candidate) {
                               return base::FilePath::CompareEqualIgnoreCase(
                                   file_extension, candidate);
                             }));
  // If Chrome is not eligible to become the default handler, do nothing.
  if (!install_static::SupportsSetAsDefaultBrowser() ||
      !RegisterChromeBrowser(chrome_exe, std::wstring(), true)) {
    return false;
  }
  // If Chrome is already the default handler, do nothing.
  if (GetChromeDefaultFileHandlerState(file_extension) == IS_DEFAULT) {
    return true;
  }
  // Open the "Select a default app for `file_extension` files" dialog.
  if (base::win::LaunchDefaultAppForFileExtensionSettings(file_extension,
                                                          parent_hwnd)) {
    return true;
  }
  // On Windows 11, fall back to the "Default apps" settings page for Chrome.
  if (base::win::GetVersion() >= base::win::Version::WIN11) {
    return base::win::LaunchSettingsDefaultApps(
        GetApplicationName(chrome_exe), InstallUtil::IsPerUserInstall());
  }
  // On Windows 10, fall back to the "Choose default apps by file type" page.
  return base::win::LaunchSettingsUri(
      L"page=SettingsPageAppsDefaults"
      L"&target=SettingsPageAppsDefaultsFileExtensionView");
}

bool ShellUtil::MakeChromeDefaultProtocolClient(
    const base::FilePath& chrome_exe,
    const std::wstring& protocol) {
  if (!install_static::SupportsSetAsDefaultBrowser())
    return false;

  if (!RegisterChromeForProtocols(
          chrome_exe, std::wstring(),
          GetBrowserProtocolAssociation(protocol, chrome_exe), true)) {
    return false;
  }

  // Windows 8 does not permit making a browser default just like that.
  // This process needs to be routed through the system's UI. Use
  // ShowMakeChromeDefaultProtocolClientSystemUI instead (below).
  if (!CanMakeChromeDefaultUnattended())
    return false;

  bool ret = true;
  // First use the "recommended" way introduced in Vista to make Chrome default
  // protocol handler.
  VLOG(1) << "Registering Chrome as default handler for " << protocol
          << " on Windows 7.";
  Microsoft::WRL::ComPtr<IApplicationAssociationRegistration> pAAR;
  HRESULT hr = ::CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                  nullptr, CLSCTX_INPROC, IID_PPV_ARGS(&pAAR));
  if (SUCCEEDED(hr)) {
    std::wstring app_name = GetApplicationName(chrome_exe);
    hr = pAAR->SetAppAsDefault(app_name.c_str(), protocol.c_str(),
                               AT_URLPROTOCOL);
  }
  if (!SUCCEEDED(hr)) {
    ret = false;
    LOG(ERROR) << "Could not make Chrome default protocol client (Windows 7):"
               << " HRESULT=" << hr << ".";
  }

  // Now use the old way to associate Chrome with the desired protocol. This
  // should not be required on Vista+, but since some applications still read
  // Software\Classes\<protocol> key directly, do this on Vista+ also.
  if (!RegisterChromeAsDefaultProtocolClientXPStyle(chrome_exe, protocol))
    ret = false;

  return ret;
}

bool ShellUtil::ShowMakeChromeDefaultProtocolClientSystemUI(
    const base::FilePath& chrome_exe,
    const std::wstring& protocol) {
  DCHECK(!CanMakeChromeDefaultUnattended());

  if (!install_static::SupportsSetAsDefaultBrowser())
    return false;

  if (!RegisterChromeForProtocols(
          chrome_exe, std::wstring(),
          GetBrowserProtocolAssociation(protocol, chrome_exe), true)) {
    return false;
  }

  ::SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nullptr, nullptr);

  bool succeeded = true;
  bool is_default =
      (GetChromeDefaultProtocolClientState(protocol) == IS_DEFAULT);
  if (!is_default) {
    // Launch the Windows settings dialog.
    succeeded =
        base::win::LaunchDefaultAppsSettingsModernDialog(protocol.c_str());
    is_default = (succeeded &&
                  GetChromeDefaultProtocolClientState(protocol) == IS_DEFAULT);
  }
  if (succeeded && is_default)
    RegisterChromeAsDefaultProtocolClientXPStyle(chrome_exe, protocol);
  return succeeded;
}

bool ShellUtil::RegisterChromeBrowser(const base::FilePath& chrome_exe,
                                      const std::wstring& unique_suffix,
                                      bool elevate_if_not_admin) {
  return RegisterChromeBrowserImpl(chrome_exe, unique_suffix,
                                   elevate_if_not_admin,
                                   /*best_effort_no_rollback=*/false);
}

void ShellUtil::RegisterChromeBrowserBestEffort(
    const base::FilePath& chrome_exe) {
  RegisterChromeBrowserImpl(chrome_exe, std::wstring(),
                            /*elevate_if_not_admin=*/false,
                            /*best_effort_no_rollback=*/true);
}

ShellUtil::ProtocolAssociations::ProtocolAssociations() = default;
ShellUtil::ProtocolAssociations::ProtocolAssociations(
    const std::vector<std::pair<std::wstring, std::wstring>>&&
        protocol_associations)
    : associations(std::move(protocol_associations)) {}
ShellUtil::ProtocolAssociations::ProtocolAssociations(
    ProtocolAssociations&& other) = default;

ShellUtil::ProtocolAssociations::~ProtocolAssociations() = default;

std::wstring ShellUtil::ProtocolAssociations::ToCommandLineArgument() const {
  // Setup.exe expects protocol associations to be passed as key/value pairs
  // in the following format:
  // |protocol|:|handler_progid|[,|protocol|:|handler_progid|, ...]
  std::wstring cmd_arg;
  for (auto i = associations.begin(); i != associations.end(); ++i) {
    base::StrAppend(&cmd_arg, {i->first, L":", i->second});
    // Add a comma delimiter for all key/value pairs except the last pair.
    if (i != std::prev(associations.end()))
      cmd_arg += (L",");
  }
  return cmd_arg;
}

std::optional<ShellUtil::ProtocolAssociations>
ShellUtil::ProtocolAssociations::FromCommandLineArgument(
    const std::wstring& argument) {
  // Given that protocol associations are stored in a string in the following
  // format:
  // |protocol|:|handler_progid|[,|protocol|:|handler_progid|, ...],
  // split the string into key value pairs and initialize ProtocolAssociations.
  base::StringPairs protocol_association_string_pairs;
  base::SplitStringIntoKeyValuePairs(base::WideToUTF8(argument), ':', ',',
                                     &protocol_association_string_pairs);

  if (protocol_association_string_pairs.empty())
    return std::nullopt;

  std::vector<std::pair<std::wstring, std::wstring>> protocol_association_pairs;
  protocol_association_pairs.reserve(protocol_association_string_pairs.size());

  for (const auto& association_pair : protocol_association_string_pairs) {
    std::wstring protocol = base::UTF8ToWide(association_pair.first);
    std::wstring handler_progid = base::UTF8ToWide(association_pair.second);
    protocol_association_pairs.emplace_back(protocol, handler_progid);
  }

  ProtocolAssociations protocol_associations(
      std::move(protocol_association_pairs));
  return protocol_associations;
}

bool ShellUtil::RegisterChromeForProtocols(
    const base::FilePath& chrome_exe,
    const std::wstring& unique_suffix,
    const ProtocolAssociations& protocol_associations,
    bool elevate_if_not_admin) {
  std::wstring suffix;
  if (!unique_suffix.empty()) {
    suffix = unique_suffix;
  } else if (!GetInstallationSpecificSuffix(chrome_exe, &suffix)) {
    return false;
  }

  bool user_level = InstallUtil::IsPerUserInstall();
  HKEY root = DetermineRegistrationRoot(user_level);

  // Look only in HKLM for system-level installs (otherwise, if a user-level
  // install is also present, it could lead
  // IsChromeRegisteredForProtocolAssociations() to think this system-level
  // install isn't registered properly as it may be shadowed by the user-level
  // install's registrations).
  uint32_t look_for_in = user_level ? RegistryEntry::LOOK_IN_HKCU_THEN_HKLM
                                    : RegistryEntry::LOOK_IN_HKLM;

  // Check if chrome is already registered with this suffix.
  if (IsChromeRegisteredForProtocolAssociations(suffix, protocol_associations,
                                                look_for_in)) {
    return true;
  }

  if (root == HKEY_CURRENT_USER || IsUserAnAdmin()) {
    // We can do this operation directly.
    // First, make sure Chrome is fully registered on this machine.
    if (!RegisterChromeBrowser(chrome_exe, suffix, false))
      return false;

    // Write in the capability for the protocol.
    std::vector<std::unique_ptr<RegistryEntry>> entries;
    GetProtocolCapabilityEntries(suffix, protocol_associations, &entries);

    // This registry value tells Windows that this 'class' is a URL scheme.
    // HKEY_CURRENT_USER\Software\Classes\<protocol>\URL Protocol
    for (const auto& association : protocol_associations.associations) {
      std::wstring url_key = base::StrCat(
          {ShellUtil::kRegClasses, kFilePathSeparator, association.first});
      entries.push_back(std::make_unique<RegistryEntry>(
          url_key, ShellUtil::kRegUrlProtocol, std::wstring()));
    }

    return AddRegistryEntries(root, entries);
  } else if (elevate_if_not_admin) {
    // Elevate to do the whole job
    base::CommandLine::SwitchMap switches{
        {installer::switches::kRegisterURLProtocol,
         protocol_associations.ToCommandLineArgument()}};
    return ElevateAndRegisterChrome(chrome_exe, suffix, &switches);
  } else {
    // Admin rights are required to register capabilities before Windows 8.
    return false;
  }
}

// static
bool ShellUtil::RemoveShortcuts(
    ShortcutLocation location,
    ShellChange level,
    const std::vector<base::FilePath>& target_paths) {
  if (!ShortcutLocationIsSupported(location))
    return true;  // Vacuous success.

  FilterTargetContains shortcut_filter(target_paths, false);
  // Main operation to apply to each shortcut in the directory specified.
  ShortcutOperationCallback shortcut_operation =
      location == SHORTCUT_LOCATION_TASKBAR_PINS
          ? base::BindRepeating(&ShortcutOpUnpinFromTaskbar)
          : base::BindRepeating(&ShortcutOpDelete);
  bool success =
      BatchShortcutAction(shortcut_filter.AsShortcutFilterCallback(),
                          shortcut_operation, location, level, nullptr);
  // Remove chrome-specific shortcut folders if they are now empty.
  if (success &&
      (location == SHORTCUT_LOCATION_START_MENU_CHROME_DIR_DEPRECATED ||
       location == SHORTCUT_LOCATION_START_MENU_CHROME_APPS_DIR ||
       location == SHORTCUT_LOCATION_APP_SHORTCUTS)) {
    success = RemoveShortcutFolderIfEmpty(location, level);
  }
  return success;
}

// static
void ShellUtil::RemoveAllShortcuts(
    ShellChange level,
    const std::vector<base::FilePath>& target_paths) {
  // Delete and unpin all shortcuts that point to |target_paths| from all
  // ShellUtil::ShortcutLocations for the given |level|.
  for (int location = SHORTCUT_LOCATION_FIRST;
       location <= SHORTCUT_LOCATION_LAST; ++location) {
    RemoveShortcuts(static_cast<ShortcutLocation>(location), level,
                    target_paths);
  }
}

// static
bool ShellUtil::RetargetShortcutsWithArgs(
    ShortcutLocation location,
    ShellChange level,
    const base::FilePath& old_target_exe,
    const base::FilePath& new_target_exe) {
  if (!ShortcutLocationIsSupported(location))
    return true;  // Vacuous success.

  FilterTargetContains shortcut_filter({old_target_exe}, true);
  ShortcutOperationCallback shortcut_operation =
      base::BindRepeating(&ShortcutOpRetarget, old_target_exe, new_target_exe);
  return BatchShortcutAction(shortcut_filter.AsShortcutFilterCallback(),
                             shortcut_operation, location, level, nullptr);
}

// static
bool ShellUtil::ShortcutListMaybeRemoveUnknownArgs(
    ShortcutLocation location,
    ShellChange level,
    const base::FilePath& chrome_exe,
    bool do_removal,
    const scoped_refptr<SharedCancellationFlag>& cancel,
    std::vector<std::pair<base::FilePath, std::wstring>>* shortcuts) {
  if (!ShortcutLocationIsSupported(location))
    return false;
  FilterTargetContains shortcut_filter({chrome_exe}, true);
  ShortcutOperationCallback shortcut_operation = base::BindRepeating(
      &ShortcutOpListOrRemoveUnknownArgs, do_removal, shortcuts);
  return BatchShortcutAction(shortcut_filter.AsShortcutFilterCallback(),
                             shortcut_operation, location, level, cancel);
}

// static
bool ShellUtil::ResetShortcutFileAttributes(ShortcutLocation location,
                                            ShellChange level,
                                            const base::FilePath& chrome_exe) {
  if (!ShortcutLocationIsSupported(location))
    return false;
  FilterTargetContains shortcut_filter({chrome_exe}, /*require_args=*/false);
  ShortcutOperationCallback shortcut_operation =
      base::BindRepeating(&ShortcutOpResetAttributes);
  return BatchShortcutAction(shortcut_filter.AsShortcutFilterCallback(),
                             shortcut_operation, location, level, nullptr);
}

bool ShellUtil::GetUserSpecificRegistrySuffix(std::wstring* suffix) {
  // Use a thread-safe cache for the user's suffix.
  static base::LazyInstance<UserSpecificRegistrySuffix>::Leaky suffix_instance =
      LAZY_INSTANCE_INITIALIZER;
  return suffix_instance.Get().GetSuffix(suffix);
}

bool ShellUtil::GetOldUserSpecificRegistrySuffix(std::wstring* suffix) {
  wchar_t user_name[256];
  DWORD size = std::size(user_name);
  if (::GetUserName(user_name, &size) == 0 || size < 1) {
    NOTREACHED();
  }
  suffix->reserve(size);
  suffix->assign(1, L'.');
  suffix->append(user_name, size - 1);
  return true;
}

// static
bool ShellUtil::RegisterFileHandlerProgIdsForAppId(
    const std::wstring& prog_id,
    const std::vector<std::wstring>& file_handler_prog_ids) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;

  // Save file handler ProgIds in the registry for use during uninstallation.
  const std::wstring prog_id_path =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, prog_id});
  entries.push_back(std::make_unique<RegistryEntry>(
      prog_id_path, kFileHandlerProgIds,
      base::JoinString(file_handler_prog_ids, L";")));

  return AddRegistryEntries(HKEY_CURRENT_USER, entries);
}

// static
std::vector<std::wstring> ShellUtil::GetFileHandlerProgIdsForAppId(
    const std::wstring& prog_id) {
  std::vector<std::wstring> file_handler_prog_ids;
  const std::wstring prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id});

  const RegKey file_handlers_key(HKEY_CURRENT_USER, prog_id_path.c_str(),
                                 KEY_QUERY_VALUE);
  std::wstring file_handler_prog_ids_value;
  if (file_handlers_key.ReadValue(
          kFileHandlerProgIds, &file_handler_prog_ids_value) == ERROR_SUCCESS) {
    file_handler_prog_ids =
        base::SplitString(file_handler_prog_ids_value, std::wstring(L";"),
                          base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
  }
  return file_handler_prog_ids;
}

// static
bool ShellUtil::AddFileAssociations(
    const std::wstring& prog_id,
    const base::CommandLine& command_line,
    const std::wstring& application_name,
    const std::wstring& file_type_name,
    const base::FilePath& application_icon_path,
    const std::set<std::wstring>& file_extensions) {
  std::vector<std::unique_ptr<RegistryEntry>> entries;

  // Create a class for this app.
  ApplicationInfo app_info;
  app_info.prog_id = prog_id;
  app_info.application_name = application_name;
  app_info.application_icon_path = application_icon_path;
  app_info.application_icon_index = 0;
  app_info.file_type_name = file_type_name;
  app_info.file_type_icon_index = 0;
  app_info.command_line = command_line.GetCommandLineStringForShell();

  GetProgIdEntries(app_info, &entries);

  std::vector<std::wstring> handled_file_extensions;

  // Associate each extension that the app can handle with the class.
  for (const auto& file_extension : file_extensions) {
    // Do not allow empty file extensions, or extensions beginning with a '.'.
    DCHECK(!file_extension.empty());
    DCHECK_NE(L'.', file_extension[0]);
    std::wstring ext(1, L'.');
    ext += file_extension;
    GetAppExtRegistrationEntries(prog_id, ext, &entries);

    handled_file_extensions.push_back(std::move(ext));
  }

  // Save handled file extensions in the registry for use during uninstallation.
  std::wstring prog_id_path =
      base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, prog_id});
  entries.push_back(std::make_unique<RegistryEntry>(
      prog_id_path, kFileExtensions,
      base::JoinString(handled_file_extensions, L";")));

  return AddRegistryEntries(HKEY_CURRENT_USER, entries);
}

// static
bool ShellUtil::DeleteFileAssociations(const std::wstring& app_prog_id) {
  const std::wstring app_prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, app_prog_id});

  // Get the list of file handler ProgIds for the app. Do this before the
  // `app_prog_id` key is deleted.
  const std::vector<std::wstring> file_handler_prog_ids =
      ShellUtil::GetFileHandlerProgIdsForAppId(app_prog_id);

  // TODO(crbug.com/40197012): This can be replaced with DeleteApplicationClass
  // once currently installed web apps have been upgraded to use per-file
  // handler ProgIds. Those web apps were only installed in Origin Trials so
  // this is just best effort.
  bool result = DeleteFileExtensionsForProgId(app_prog_id);

  // Delete registry entries for the file handler ProgIds.
  for (const auto& file_handler_prog_id : file_handler_prog_ids)
    result &= DeleteFileExtensionsForProgId(file_handler_prog_id);

  ::SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nullptr, nullptr);
  return result;
}

// static
bool ShellUtil::AddAppProtocolAssociations(
    const std::vector<std::wstring>& protocols,
    const std::wstring& prog_id) {
  base::FilePath chrome_exe;
  if (!base::PathService::Get(base::FILE_EXE, &chrome_exe)) {
    NOTREACHED();
  }

  if (!RegisterApplicationForProtocols(protocols, prog_id, chrome_exe))
    return false;

  bool success = true;
  for (const auto& protocol : protocols) {
    // This registry value tells Windows that this 'class' is a URL scheme.
    // HKEY_CURRENT_USER\Software\Classes\<protocol>\URL Protocol
    std::wstring url_key =
        base::StrCat({ShellUtil::kRegClasses, kFilePathSeparator, protocol});

    std::vector<std::unique_ptr<RegistryEntry>> entries;
    entries.push_back(std::make_unique<RegistryEntry>(
        url_key, ShellUtil::kRegUrlProtocol, std::wstring()));

    if (!AddRegistryEntries(HKEY_CURRENT_USER, entries))
      success = false;

    // Removing the existing user choice for a given protocol forces Windows to
    // present a disambiguation dialog the next time this protocol is invoked
    // from the OS.
    std::unique_ptr<RegistryEntry> entry = GetProtocolUserChoiceEntry(protocol);
    if (!installer::DeleteRegistryValue(HKEY_CURRENT_USER, entry->key_path(),
                                        WorkItem::kWow64Default, kRegProgId)) {
      success = false;
    }
  }

  return success;
}

// static
bool ShellUtil::RemoveAppProtocolAssociations(const std::wstring& prog_id) {
  // Delete the |prog_id| value from HKEY_CURRENT_USER\RegisteredApplications.
  installer::DeleteRegistryValue(HKEY_CURRENT_USER,
                                 ShellUtil::kRegRegisteredApplications,
                                 WorkItem::kWow64Default, prog_id);

  // Delete the key
  // HKEY_CURRENT_USER\Software\[CompanyPathName\]ProductPathName[install_suffix]\AppProtocolHandlers\|prog_id|.
  std::wstring app_key_path(install_static::GetRegistryPath());
  app_key_path.append(ShellUtil::kRegAppProtocolHandlers);
  app_key_path.push_back(base::FilePath::kSeparators[0]);
  app_key_path.append(prog_id);

  return installer::DeleteRegistryKey(HKEY_CURRENT_USER, app_key_path,
                                      WorkItem::kWow64Default);
}

// static
bool ShellUtil::AddApplicationClass(
    const std::wstring& prog_id,
    const base::CommandLine& shell_open_command_line,
    const std::wstring& application_name,
    const std::wstring& application_description,
    const base::FilePath& icon_path) {
  ApplicationInfo app_info;

  app_info.prog_id = prog_id;
  app_info.file_type_name = application_description;
  app_info.application_description = application_description;
  app_info.file_type_icon_path = icon_path;
  app_info.command_line =
      shell_open_command_line.GetCommandLineStringForShell();
  app_info.application_name = application_name;
  app_info.application_icon_path = icon_path;
  app_info.application_icon_index = 0;

  std::vector<std::unique_ptr<RegistryEntry>> entries;
  GetProgIdEntries(app_info, &entries);

  return AreEntriesAsDesired(entries, RegistryEntry::LOOK_IN_HKCU) ||
         AddRegistryEntries(HKEY_CURRENT_USER, entries);
}

// static
bool ShellUtil::DeleteApplicationClass(const std::wstring& prog_id) {
  std::wstring prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id});

  // Delete the key HKEY_CURRENT_USER\Software\Classes\|prog_id|.
  return installer::DeleteRegistryKey(HKEY_CURRENT_USER, prog_id_path,
                                      WorkItem::kWow64Default);
}

// static
ShellUtil::ApplicationInfo ShellUtil::GetApplicationInfoForProgId(
    const std::wstring& prog_id) {
  ApplicationInfo app_info;
  app_info.prog_id = prog_id;

  std::wstring prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id});

  RegKey class_key(HKEY_CURRENT_USER, prog_id_path.c_str(), KEY_QUERY_VALUE);

  class_key.ReadValue(L"", &app_info.file_type_name);

  // file_type_icon_*
  std::wstring file_type_icon_path = prog_id_path + kRegDefaultIcon;
  RegKey file_type_icon_key(HKEY_CURRENT_USER, file_type_icon_path.c_str(),
                            KEY_QUERY_VALUE);

  std::wstring file_type_icon_value;
  file_type_icon_key.ReadValue(L"", &file_type_icon_value);
  std::optional<std::pair<base::FilePath, int>> file_type_icon_parts =
      ShellUtil::ParseIconLocation(file_type_icon_value);

  if (file_type_icon_parts.has_value()) {
    app_info.file_type_icon_path = file_type_icon_parts->first;
    app_info.file_type_icon_index = file_type_icon_parts->second;
  }

  // app_info.command_line
  RegKey command_line_key(HKEY_CURRENT_USER,
                          (prog_id_path + kRegShellOpen).c_str(),
                          KEY_QUERY_VALUE);
  command_line_key.ReadValue(L"", &app_info.command_line);

  std::wstring application_path = prog_id_path + kRegApplication;
  RegKey application_key(HKEY_CURRENT_USER, application_path.c_str(),
                         KEY_QUERY_VALUE);

  // app_info.app_id
  application_key.ReadValue(kRegAppUserModelId, &app_info.app_id);

  // User-visible details
  application_key.ReadValue(kRegApplicationName, &app_info.application_name);
  application_key.ReadValue(kRegApplicationDescription,
                            &app_info.application_description);
  application_key.ReadValue(kRegApplicationCompany, &app_info.publisher_name);

  // application_icon_*
  std::wstring application_icon_value;
  application_key.ReadValue(ShellUtil::kRegApplicationIcon,
                            &application_icon_value);
  std::optional<std::pair<base::FilePath, int>> application_icon_parts =
      ShellUtil::ParseIconLocation(application_icon_value);

  if (application_icon_parts.has_value()) {
    app_info.application_icon_path = application_icon_parts.value().first;
    app_info.application_icon_index = application_icon_parts.value().second;
  }

  return app_info;
}

// static
std::wstring ShellUtil::GetAppName(const std::wstring& prog_id) {
  std::wstring prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id});
  std::wstring app_name;
  // Get the app name from value ApplicationName at
  // HKEY_CURRENT_USER\Software\Classes\|prog_id|\Application.
  std::wstring application_path = prog_id_path + kRegApplication;
  RegKey application_key(HKEY_CURRENT_USER, application_path.c_str(),
                         KEY_QUERY_VALUE);
  if (application_key.ReadValue(kRegApplicationName, &app_name) ==
      ERROR_SUCCESS) {
    return app_name;
  }
  return L"";
}

// static
base::FilePath ShellUtil::GetApplicationPathForProgId(
    const std::wstring& prog_id) {
  std::wstring prog_id_path =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id});
  std::wstring shell_open_key =
      base::StrCat({kRegClasses, kFilePathSeparator, prog_id, kRegShellOpen});
  std::wstring command_line;
  const RegKey command_line_key(HKEY_CURRENT_USER, shell_open_key.c_str(),
                                KEY_QUERY_VALUE);
  if (command_line_key.ReadValue(L"", &command_line) == ERROR_SUCCESS)
    return base::CommandLine::FromString(command_line).GetProgram();

  return base::FilePath();
}

// static
bool ShellUtil::AddRegistryEntries(
    HKEY root,
    const std::vector<std::unique_ptr<RegistryEntry>>& entries,
    bool best_effort_no_rollback) {
  std::unique_ptr<WorkItemList> items(WorkItem::CreateWorkItemList());
  items->set_rollback_enabled(!best_effort_no_rollback);
  items->set_best_effort(best_effort_no_rollback);
  for (const auto& entry : entries)
    entry->AddToWorkItemList(root, items.get());

  // Apply all the registry changes and if there is a problem, rollback
  if (!items->Do()) {
    items->Rollback();
    return false;
  }
  return true;
}