/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"
#include "nsIPrefBranch.idl"

interface nsIFile;

/**
 * A helper function for reading access statistics for preferences.
 * See nsIPrefService.readStats for more details.
 */
[function, scriptable, uuid(c3f0cedc-e244-4316-b33a-80306a1c35a1)]
interface nsIPrefStatsCallback : nsISupports
{
  void visit(in ACString prefName, in unsigned long accessCount);
};

[scriptable, uuid(0a2dbc02-2218-4687-b151-33d890676e00)]
interface nsIPrefObserver : nsISupports
{
  /**
   * Invoked when a string preference is witnessed.  kind will be "Default" or "User".
   */
  void onStringPref(in string kind, in string name, in string value, in boolean isSticky, in boolean isLocked);

  /**
   * Invoked when a integer preference is witnessed.  kind will be "Default" or "User".
   */
  void onIntPref(in string kind, in string name, in long value, in boolean isSticky, in boolean isLocked);

  /**
   * Invoked when a boolean preference is witnessed.  kind will be "Default" or "User".
   */
  void onBoolPref(in string kind, in string name, in boolean value, in boolean isSticky, in boolean isLocked);

  /**
   * Invoked when the prefs parser encounters an error.
   */
  void onError(in string message);
};

/**
 * The nsIPrefService interface is the main entry point into the back end
 * preferences management library. The preference service is directly
 * responsible for the management of the preferences files and also facilitates
 * access to the preference branch object which allows the direct manipulation
 * of the preferences themselves.
 *
 * @see nsIPrefBranch
 */

[scriptable, uuid(1f84fd56-3956-40df-b86a-1ea01402ee96)]
interface nsIPrefService : nsISupports
{
  /**
   * Called to completely flush and re-initialize the preferences system.
   *
   * @throws Error The preference service failed to restart correctly.
   */
  void resetPrefs();

  /**
   * Called to write current preferences state to a file.
   *
   * @param aFile The file to be written.
   *
   * @note
   * If nullptr is passed in for the aFile parameter the preference data is
   * written out to the current preferences file (usually prefs.js.)
   *
   * @throws Error File failed to write.
   *
   * @see readUserPrefsFromFile
   * @see nsIFile
   */
  void savePrefFile(in nsIFile aFile);

  /**
   * Called to write current preferences state to a file off of the main thread.
   * This differs from savePrefFile in that null is not accepted for the aFile
   * parameter, and aFile cannot be pointing at the current preferences file.
   *
   * The backup will be written to disk off of the main thread, unless the
   * preferences service is not configured to write to disk off of the main
   * thread.
   *
   * @param aFile The file to be written.
   * @returns A DOM promise that resolves when the backup is complete.
   *
   * @see readUserPrefsFromFile
   * @see nsIFile
   */
  [implicit_jscontext]
  Promise backupPrefFile(in nsIFile aFile);

  /**
   * Call to get a Preferences "Branch" which accesses user preference data.
   * Using a Set method on this object will always create or set a user
   * preference value. When using a Get method a user set value will be
   * returned if one exists, otherwise a default value will be returned.
   *
   * @param aPrefRoot The preference "root" on which to base this "branch".
   *                  For example, if the root "browser.startup." is used, the
   *                  branch will be able to easily access the preferences
   *                  "browser.startup.page", "browser.startup.homepage", or
   *                  "browser.startup.homepage_override" by simply requesting
   *                  "page", "homepage", or "homepage_override". nullptr or ""
   *                  may be used to access to the entire preference "tree".
   *
   * @return nsIPrefBranch The object representing the requested branch.
   *
   * @see getDefaultBranch
   */
  nsIPrefBranch getBranch(in string aPrefRoot);

  /**
   * Call to get a Preferences "Branch" which accesses only the default
   * preference data. Using a Set method on this object will always create or
   * set a default preference value. When using a Get method a default value
   * will always be returned.
   *
   * @param aPrefRoot The preference "root" on which to base this "branch".
   *                  For example, if the root "browser.startup." is used, the
   *                  branch will be able to easily access the preferences
   *                  "browser.startup.page", "browser.startup.homepage", or
   *                  "browser.startup.homepage_override" by simply requesting
   *                  "page", "homepage", or "homepage_override". nullptr or ""
   *                  may be used to access to the entire preference "tree".
   *
   * @note
   * Few consumers will want to create default branch objects. Many of the
   * branch methods do nothing on a default branch because the operations only
   * make sense when applied to user set preferences.
   *
   * @return nsIPrefBranch The object representing the requested default branch.
   *
   * @see getBranch
   */
  nsIPrefBranch getDefaultBranch(in string aPrefRoot);

  /**
   * The preference service is 'dirty' if there are changes to user preferences
   * that have not been written to disk
   */
  readonly attribute boolean dirty;

  /**
   * Read in the preferences specified in a default preference file. This
   * method does not clear preferences that were already set, but it may
   * overwrite existing preferences.
   *
   * @param aFile The file to be read.
   *
   * @throws Error File failed to read or contained invalid data.
   * @note This method is intended for internal unit testing only!
   */
  void readDefaultPrefsFromFile(in nsIFile aFile);

  /**
   * Like readDefaultPrefsFromFile, but for a user prefs file.
   */
  void readUserPrefsFromFile(in nsIFile aFile);

  /**
   * Usage statistics for performance tests. This function takes a function
   * that is passed (preferenceName, accessCount) as arguments for every
   * recorded preference. You can use this function to build e.g. a JS object
   * holding that data.
   *
   * This is not implemented in non-debug builds and will throw an error.
   */
  void readStats(in nsIPrefStatsCallback callback);

  /**
   * Reset usage statistics for performance tests.
   *
   * This is not implemented in non-debug builds and will throw an error.
   */
  void resetStats();

  /**
   * Parse the given bytes, invoking callbacks on the given observer.
   *
   * This method does not modify any preferences.
   *
   * @param bytes The data to parse.  This data may be UTF-8 encoded, but is not
   *              required to be so: the prefs parser will determine the encoding
   *              automatically.
   * @param observer The observer to invoke callbacks on.  Parsing errors will
   *                 be reported via the onError callback.
   * @param pathLabel An optional string with which to label errors.
   */
  void parsePrefsFromBuffer(in Array<uint8_t> bytes,
                            in nsIPrefObserver observer,
                            [optional] in string pathLabel);

  /**
   * Last modified time of the user pref file when initially read, in
   * milliseconds. Can be 0 (unix epoch) if the file didn't exist when we
   * started.
   */
  readonly attribute PRTime userPrefsFileLastModifiedAtStartup;
};

%{C++

#define NS_PREFSERVICE_CID                             \
  { /* {1cd91b88-1dd2-11b2-92e1-ed22ed298000} */       \
    0x91ca2441,                                        \
    0x050f,                                            \
    0x4f7c,                                            \
    { 0x9d, 0xf8, 0x75, 0xb4, 0x0e, 0xa4, 0x01, 0x56 } \
  }

#define NS_PREFSERVICE_CONTRACTID "@mozilla.org/preferences-service;1"

/**
 * Notification sent before reading the default user preferences files.
 */
#define NS_PREFSERVICE_READ_TOPIC_ID "prefservice:before-read-userprefs"

/**
 * Notification sent when after reading app-provided default
 * preferences, but before user profile override defaults are loaded.
 */
#define NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID "prefservice:after-app-defaults"

%}