// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "extensions/renderer/script_injection_manager.h"

#include <memory>
#include <utility>

#include "base/auto_reset.h"
#include "base/containers/cxx20_erase.h"
#include "base/feature_list.h"
#include "base/functional/bind.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/ranges/algorithm.h"
#include "base/values.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_frame_observer.h"
#include "content/public/renderer/render_thread.h"
#include "extensions/common/extension.h"
#include "extensions/common/extension_features.h"
#include "extensions/common/extension_messages.h"
#include "extensions/common/extension_set.h"
#include "extensions/common/mojom/host_id.mojom.h"
#include "extensions/renderer/extension_frame_helper.h"
#include "extensions/renderer/extension_injection_host.h"
#include "extensions/renderer/programmatic_script_injector.h"
#include "extensions/renderer/renderer_extension_registry.h"
#include "extensions/renderer/script_injection.h"
#include "extensions/renderer/scripts_run_info.h"
#include "extensions/renderer/web_ui_injection_host.h"
#include "ipc/ipc_message_macros.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
#include "third_party/blink/public/platform/web_url_error.h"
#include "third_party/blink/public/web/web_document.h"
#include "third_party/blink/public/web/web_frame.h"
#include "third_party/blink/public/web/web_local_frame.h"
#include "third_party/blink/public/web/web_view.h"
#include "url/gurl.h"

namespace extensions {

namespace {

// The length of time to wait after the DOM is complete to try and run user
// scripts.
const int kScriptIdleTimeoutInMs = 200;

// Returns the RunLocation that follows |run_location|.
absl::optional<mojom::RunLocation> NextRunLocation(
    mojom::RunLocation run_location) {
  switch (run_location) {
    case mojom::RunLocation::kDocumentStart:
      return mojom::RunLocation::kDocumentEnd;
    case mojom::RunLocation::kDocumentEnd:
      return mojom::RunLocation::kDocumentIdle;
    case mojom::RunLocation::kDocumentIdle:
      return absl::nullopt;
    case mojom::RunLocation::kUndefined:
    case mojom::RunLocation::kRunDeferred:
    case mojom::RunLocation::kBrowserDriven:
      return absl::nullopt;
  }
  NOTREACHED();
}

}  // namespace

class ScriptInjectionManager::RFOHelper : public content::RenderFrameObserver {
 public:
  RFOHelper(content::RenderFrame* render_frame,
            ScriptInjectionManager* manager);
  ~RFOHelper() override;

  void Initialize();

 private:
  // RenderFrameObserver implementation.
  void DidCreateNewDocument() override;
  void DidCreateDocumentElement() override;
  void DidFailProvisionalLoad() override;
  void DidDispatchDOMContentLoadedEvent() override;
  void WillDetach() override;
  void OnDestruct() override;
  void OnStop() override;

  // Tells the ScriptInjectionManager to run tasks associated with
  // document_idle.
  void RunIdle();

  void StartInjectScripts(mojom::RunLocation run_location);

  // Indicate that the frame is no longer valid because it is starting
  // a new load or closing.
  void InvalidateAndResetFrame(bool force_reset);

  // The owning ScriptInjectionManager.
  raw_ptr<ScriptInjectionManager, ExperimentalRenderer> manager_;

  bool should_run_idle_ = true;

  base::WeakPtrFactory<RFOHelper> weak_factory_{this};
};

ScriptInjectionManager::RFOHelper::RFOHelper(content::RenderFrame* render_frame,
                                             ScriptInjectionManager* manager)
    : content::RenderFrameObserver(render_frame), manager_(manager) {}

ScriptInjectionManager::RFOHelper::~RFOHelper() {
}

void ScriptInjectionManager::RFOHelper::Initialize() {
  // Set up for the initial empty document, for which the Document created
  // events do not happen as it's already present.
  DidCreateNewDocument();
  // The initial empty document for a main frame may have scripts attached to it
  // but we do not want to invalidate the frame and lose them when the next
  // document loads. For example the IncognitoApiTest.IncognitoSplitMode test
  // does `chrome.tabs.create()` with a script to be run, which is added to the
  // frame before it navigates, so it needs to be preserved. However scripts in
  // child frames are expected to be run inside the initial empty document. For
  // example the ExecuteScriptApiTest.FrameWithHttp204 test creates a child
  // frame at about:blank and expects to run injected scripts inside it.
  // This is all quite inconsistent however tests both depend on us queuing and
  // not queueing the kDocumentStart events in the initial empty document.
  if (!render_frame()->IsMainFrame()) {
    DidCreateDocumentElement();
  }
}

void ScriptInjectionManager::RFOHelper::DidCreateNewDocument() {
  // A new document is going to be shown, so invalidate the old document state.
  // Don't force-reset the frame, because it is possible that a script injection
  // was scheduled before the page was loaded, e.g. by navigating to a
  // javascript: URL before the page has loaded.
  constexpr bool kForceReset = false;
  InvalidateAndResetFrame(kForceReset);
}

void ScriptInjectionManager::RFOHelper::DidCreateDocumentElement() {
  ExtensionFrameHelper::Get(render_frame())
      ->ScheduleAtDocumentStart(base::BindOnce(
          &ScriptInjectionManager::RFOHelper::StartInjectScripts,
          weak_factory_.GetWeakPtr(), mojom::RunLocation::kDocumentStart));
}

void ScriptInjectionManager::RFOHelper::DidFailProvisionalLoad() {
  auto it = manager_->frame_statuses_.find(render_frame());
  if (it != manager_->frame_statuses_.end() &&
      it->second == mojom::RunLocation::kDocumentStart) {
    // Since the provisional load failed, the frame stays at its previous loaded
    // state and origin (or the parent's origin for new/about:blank frames).
    // Reset the frame to kDocumentIdle in order to reflect that the frame is
    // done loading, and avoid any deadlock in the system.
    //
    // We skip injection of kDocumentEnd and kDocumentIdle scripts, because the
    // injections closely follow the DOMContentLoaded (and onload) events, which
    // are not triggered after a failed provisional load.
    // This assumption is verified in the checkDOMContentLoadedEvent subtest of
    // ExecuteScriptApiTest.FrameWithHttp204 (browser_tests).
    constexpr bool kForceReset = true;
    InvalidateAndResetFrame(kForceReset);
    should_run_idle_ = false;
    manager_->frame_statuses_[render_frame()] =
        mojom::RunLocation::kDocumentIdle;
  }
}

void ScriptInjectionManager::RFOHelper::DidDispatchDOMContentLoadedEvent() {
  DCHECK(content::RenderThread::Get());
  ExtensionFrameHelper::Get(render_frame())
      ->ScheduleAtDocumentEnd(base::BindOnce(
          &ScriptInjectionManager::RFOHelper::StartInjectScripts,
          weak_factory_.GetWeakPtr(), mojom::RunLocation::kDocumentEnd));

  // We try to run idle in two places: a delayed task here and in response to
  // ContentRendererClient::RunScriptsAtDocumentIdle().
  // DidDispatchDOMContentLoadedEvent() corresponds to completing the document's
  // load, whereas RunScriptsAtDocumentIdle() corresponds to completing the
  // document and all subresources' load (but before the window.onload event).
  // We don't want to hold up script injection for a particularly slow
  // subresource, so we set a delayed task from here - but if we finish
  // everything before that point (i.e., RunScriptsAtDocumentIdle() is
  // triggered), then there's no reason to keep waiting.
  render_frame()
      ->GetTaskRunner(blink::TaskType::kInternalDefault)
      ->PostDelayedTask(
          FROM_HERE,
          base::BindOnce(&ScriptInjectionManager::RFOHelper::RunIdle,
                         weak_factory_.GetWeakPtr()),
          base::Milliseconds(kScriptIdleTimeoutInMs));

  ExtensionFrameHelper::Get(render_frame())
      ->ScheduleAtDocumentIdle(
          base::BindOnce(&ScriptInjectionManager::RFOHelper::RunIdle,
                         weak_factory_.GetWeakPtr()));
}

void ScriptInjectionManager::RFOHelper::WillDetach() {
  // The frame is closing - invalidate.
  constexpr bool kForceReset = true;
  InvalidateAndResetFrame(kForceReset);
}

void ScriptInjectionManager::RFOHelper::OnDestruct() {
  manager_->RemoveObserver(this);
}

void ScriptInjectionManager::RFOHelper::OnStop() {
  // If the navigation request fails (e.g. 204/205/downloads), notify the
  // extension to avoid keeping the frame in a START state indefinitely which
  // leads to deadlocks.
  DidFailProvisionalLoad();
}

void ScriptInjectionManager::RFOHelper::RunIdle() {
  // Only notify the manager if the frame hasn't already had idle run since the
  // task to RunIdle() was posted.
  if (should_run_idle_) {
    should_run_idle_ = false;
    manager_->StartInjectScripts(render_frame(),
                                 mojom::RunLocation::kDocumentIdle);
  }
}

void ScriptInjectionManager::RFOHelper::StartInjectScripts(
    mojom::RunLocation run_location) {
  manager_->StartInjectScripts(render_frame(), run_location);
}

void ScriptInjectionManager::RFOHelper::InvalidateAndResetFrame(
    bool force_reset) {
  // Invalidate any pending idle injections, and reset the frame inject on idle.
  weak_factory_.InvalidateWeakPtrs();
  // We reset to inject on idle, because the frame can be reused (in the case of
  // navigation).
  should_run_idle_ = true;

  // Reset the frame if either |force_reset| is true, or if the manager is
  // keeping track of the state of the frame (in which case we need to clean it
  // up).
  if (force_reset || manager_->frame_statuses_.count(render_frame()) != 0)
    manager_->InvalidateForFrame(render_frame());
}

ScriptInjectionManager::ScriptInjectionManager(
    UserScriptSetManager* user_script_set_manager)
    : user_script_set_manager_(user_script_set_manager) {
  user_script_set_manager_observation_.Observe(user_script_set_manager_.get());
}

ScriptInjectionManager::~ScriptInjectionManager() {
  for (const auto& injection : pending_injections_)
    injection->invalidate_render_frame();
  for (const auto& injection : running_injections_)
    injection->invalidate_render_frame();
}

void ScriptInjectionManager::OnRenderFrameCreated(
    content::RenderFrame* render_frame) {
  rfo_helpers_.push_back(std::make_unique<RFOHelper>(render_frame, this));
  rfo_helpers_.back()->Initialize();
}

void ScriptInjectionManager::OnExtensionUnloaded(
    const std::string& extension_id) {
  for (auto iter = pending_injections_.begin();
      iter != pending_injections_.end();) {
    if ((*iter)->host_id().id == extension_id) {
      (*iter)->OnHostRemoved();
      iter = pending_injections_.erase(iter);
    } else {
      ++iter;
    }
  }
}

void ScriptInjectionManager::OnInjectionFinished(ScriptInjection* injection) {
  base::EraseIf(running_injections_,
                [&injection](const std::unique_ptr<ScriptInjection>& mode) {
                  return injection == mode.get();
                });
}

void ScriptInjectionManager::OnUserScriptsUpdated(
    const mojom::HostID& changed_host) {
  base::EraseIf(
      pending_injections_,
      [&changed_host](const std::unique_ptr<ScriptInjection>& injection) {
        return changed_host == injection->host_id();
      });
}

void ScriptInjectionManager::RemoveObserver(RFOHelper* helper) {
  for (auto iter = rfo_helpers_.begin(); iter != rfo_helpers_.end(); ++iter) {
    if (iter->get() == helper) {
      rfo_helpers_.erase(iter);
      break;
    }
  }
}

void ScriptInjectionManager::InvalidateForFrame(content::RenderFrame* frame) {
  // If the frame invalidated is the frame being injected into, we need to
  // note it.
  active_injection_frames_.erase(frame);

  base::EraseIf(pending_injections_,
                [&frame](const std::unique_ptr<ScriptInjection>& injection) {
                  return injection->render_frame() == frame;
                });

  frame_statuses_.erase(frame);
}

void ScriptInjectionManager::StartInjectScripts(
    content::RenderFrame* frame,
    mojom::RunLocation run_location) {
  auto iter = frame_statuses_.find(frame);
  // We also don't execute if we detect that the run location is somehow out of
  // order. This can happen if:
  // - The first run location reported for the frame isn't kDocumentStart, or
  // - The run location reported doesn't immediately follow the previous
  //   reported run location.
  // We don't want to run because extensions may have requirements that scripts
  // running in an earlier run location have run by the time a later script
  // runs. Better to just not run.
  // Note that we check run_location > NextRunLocation() in the second clause
  // (as opposed to !=) because earlier signals (like DidCreateDocumentElement)
  // can happen multiple times, so we can receive earlier/equal run locations.
  bool invalid_run_order = false;
  if (iter == frame_statuses_.end()) {
    invalid_run_order = (run_location != mojom::RunLocation::kDocumentStart);
  } else {
    absl::optional<mojom::RunLocation> next = NextRunLocation(iter->second);
    if (next)
      invalid_run_order = run_location > next.value();
  }
  if (invalid_run_order) {
    // We also invalidate the frame, because the run order of pending injections
    // may also be bad.
    InvalidateForFrame(frame);
    return;
  } else if (iter != frame_statuses_.end() && iter->second >= run_location) {
    // Certain run location signals (like DidCreateDocumentElement) can happen
    // multiple times. Ignore the subsequent signals.
    return;
  }

  // Otherwise, all is right in the world, and we can get on with the
  // injections!
  frame_statuses_[frame] = run_location;
  InjectScripts(frame, run_location);
}

void ScriptInjectionManager::InjectScripts(content::RenderFrame* frame,
                                           mojom::RunLocation run_location) {
  // Find any injections that want to run on the given frame.
  ScriptInjectionVector frame_injections;
  for (auto iter = pending_injections_.begin();
       iter != pending_injections_.end();) {
    if ((*iter)->render_frame() == frame) {
      frame_injections.push_back(std::move(*iter));
      iter = pending_injections_.erase(iter);
    } else {
      ++iter;
    }
  }

  // Add any injections for user scripts.
  int tab_id = ExtensionFrameHelper::Get(frame)->tab_id();
  user_script_set_manager_->GetAllInjections(&frame_injections, frame, tab_id,
                                             run_location);

  // Note that we are running in |frame|.
  active_injection_frames_.insert(frame);

  ScriptsRunInfo scripts_run_info(frame, run_location);

  for (auto iter = frame_injections.begin(); iter != frame_injections.end();) {
    // It's possible for the frame to be invalidated in the course of injection
    // (if a script removes its own frame, for example). If this happens, abort.
    if (!active_injection_frames_.count(frame))
      break;
    std::unique_ptr<ScriptInjection> injection(std::move(*iter));
    iter = frame_injections.erase(iter);
    TryToInject(std::move(injection), run_location, &scripts_run_info);
  }

  // We are done running in the frame.
  active_injection_frames_.erase(frame);

  scripts_run_info.LogRun(activity_logging_enabled_);
}

void ScriptInjectionManager::OnInjectionStatusUpdated(
    ScriptInjection::InjectionStatus status,
    ScriptInjection* injection) {
  switch (status) {
    case ScriptInjection::InjectionStatus::kPermitted:
      ScriptInjectionManager::OnPermitScriptInjectionHandled(injection);
      break;
    case ScriptInjection::InjectionStatus::kFinished:
      ScriptInjectionManager::OnInjectionFinished(injection);
      break;
  }
}

void ScriptInjectionManager::TryToInject(
    std::unique_ptr<ScriptInjection> injection,
    mojom::RunLocation run_location,
    ScriptsRunInfo* scripts_run_info) {
  // Try to inject the script. If the injection is waiting (i.e., for
  // permission), add it to the list of pending injections. If the injection
  // has blocked, add it to the list of running injections.
  // The Unretained below is safe because this object owns all the
  // ScriptInjections, so is guaranteed to outlive them.
  switch (injection->TryToInject(
      run_location, scripts_run_info,
      base::BindOnce(&ScriptInjectionManager::OnInjectionStatusUpdated,
                     base::Unretained(this)))) {
    case ScriptInjection::INJECTION_WAITING:
      pending_injections_.push_back(std::move(injection));
      break;
    case ScriptInjection::INJECTION_BLOCKED:
      running_injections_.push_back(std::move(injection));
      break;
    case ScriptInjection::INJECTION_FINISHED:
      break;
  }
}

void ScriptInjectionManager::HandleExecuteCode(
    mojom::ExecuteCodeParamsPtr params,
    mojom::LocalFrame::ExecuteCodeCallback callback,
    content::RenderFrame* render_frame) {
  std::unique_ptr<const InjectionHost> injection_host;
  if (params->host_id->type == mojom::HostID::HostType::kExtensions) {
    injection_host = ExtensionInjectionHost::Create(params->host_id->id);
    if (!injection_host) {
      std::move(callback).Run(base::EmptyString(), GURL::EmptyGURL(),
                              absl::nullopt);
      return;
    }
  } else if (params->host_id->type == mojom::HostID::HostType::kWebUi) {
    injection_host = std::make_unique<WebUIInjectionHost>(*params->host_id);
  }

  mojom::RunLocation run_at = params->run_at;
  auto injection = std::make_unique<ScriptInjection>(
      std::make_unique<ProgrammaticScriptInjector>(std::move(params),
                                                   std::move(callback)),
      render_frame, std::move(injection_host), run_at,
      activity_logging_enabled_);

  FrameStatusMap::const_iterator iter = frame_statuses_.find(render_frame);
  mojom::RunLocation run_location = iter == frame_statuses_.end()
                                        ? mojom::RunLocation::kUndefined
                                        : iter->second;

  ScriptsRunInfo scripts_run_info(render_frame, run_location);
  TryToInject(std::move(injection), run_location, &scripts_run_info);
}

void ScriptInjectionManager::ExecuteDeclarativeScript(
    content::RenderFrame* render_frame,
    int tab_id,
    const ExtensionId& extension_id,
    const std::string& script_id,
    const GURL& url) {
  std::unique_ptr<ScriptInjection> injection =
      user_script_set_manager_->GetInjectionForDeclarativeScript(
          script_id, render_frame, tab_id, url, extension_id);
  if (injection.get()) {
    ScriptsRunInfo scripts_run_info(render_frame,
                                    mojom::RunLocation::kBrowserDriven);
    // TODO(https://crbug.com/1186525): Use return value of TryToInject for
    // error handling.
    TryToInject(std::move(injection), mojom::RunLocation::kBrowserDriven,
                &scripts_run_info);

    scripts_run_info.LogRun(activity_logging_enabled_);
  }
}

void ScriptInjectionManager::OnPermitScriptInjectionHandled(
    ScriptInjection* injection) {
  auto iter = base::ranges::find(pending_injections_, injection,
                                 &std::unique_ptr<ScriptInjection>::get);
  if (iter == pending_injections_.end())
    return;
  DCHECK((*iter)->host_id().type == mojom::HostID::HostType::kExtensions);

  // At this point, because the injection is present in pending_injections_, we
  // know that this is the same page that issued the request (otherwise,
  // RFOHelper::InvalidateAndResetFrame would have caused it to be cleared out).

  std::unique_ptr<ScriptInjection> script_injection(std::move(*iter));
  pending_injections_.erase(iter);

  ScriptsRunInfo scripts_run_info(script_injection->render_frame(),
                                  mojom::RunLocation::kRunDeferred);
  ScriptInjection::InjectionResult res =
      script_injection->OnPermissionGranted(&scripts_run_info);
  if (res == ScriptInjection::INJECTION_BLOCKED)
    running_injections_.push_back(std::move(script_injection));
  scripts_run_info.LogRun(activity_logging_enabled_);
}

}  // namespace extensions