tor-browser

nsIPrefBranch.idl (18627B)

---

/* -*- 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"

%{C++
#include "nsLiteralString.h"
%}

interface nsIObserver;

/**
* The nsIPrefBranch interface is used to manipulate the preferences data. This
* object may be obtained from the preferences service (nsIPrefService) and
* used to get and set default and/or user preferences across the application.
*
* This object is created with a "root" value which describes the base point in
* the preferences "tree" from which this "branch" stems. Preferences are
* accessed off of this root by using just the final portion of the preference.
* For example, if this object is created with the root "browser.startup.",
* the preferences "browser.startup.page", "browser.startup.homepage",
* and "browser.startup.homepage_override" can be accessed by simply passing
* "page", "homepage", or "homepage_override" to the various Get/Set methods.
*
* @see nsIPrefService
*/

[scriptable, builtinclass, uuid(55d25e49-793f-4727-a69f-de8b15f4b985)]
interface nsIPrefBranch : nsISupports
{

 /**
  * Values describing the basic preference types.
  * Manually reused in GeckoPreferences.java and should be synced when changed.
  *
  * @see getPrefType
  */
 const long PREF_INVALID = 0;
 const long PREF_STRING = 32;
 const long PREF_INT = 64;
 const long PREF_BOOL = 128;

 /**
  * Called to get the root on which this branch is based, such as
  * "browser.startup."
  */
 readonly attribute ACString root;

 /**
  * Called to determine the type of a specific preference.
  *
  * @param aPrefName The preference to get the type of.
  *
  * @return long     A value representing the type of the preference. This
  *                  value will be PREF_STRING, PREF_INT, or PREF_BOOL.
  */
 long getPrefType(in string aPrefName);

 /**
  * Called to get the state of an individual boolean preference.
  *
  * @param aPrefName The boolean preference to get the state of.
  * @param aDefaultValue The value to return if the preference is not set.
  *
  * @return boolean  The value of the requested boolean preference.
  *
  * @see setBoolPref
  */
 [optional_argc,binaryname(GetBoolPrefWithDefault)]
 boolean getBoolPref(in string aPrefName, [optional] in boolean aDefaultValue);
 [noscript,binaryname(GetBoolPref)]
 boolean getBoolPrefXPCOM(in string aPrefName);

 /**
  * Called to set the state of an individual boolean preference.
  *
  * @param aPrefName The boolean preference to set the state of.
  * @param aValue    The boolean value to set the preference to.
  *
  * @throws Error if setting failed or the preference has a default
            value of a type other than boolean.
  *
  * @see getBoolPref
  */
 void setBoolPref(in string aPrefName, in boolean aValue);

 /**
  * Called to get the state of an individual floating-point preference.
  * "Floating point" preferences are really string preferences that
  * are converted to floating point numbers.
  *
  * @param aPrefName The floating point preference to get the state of.
  * @param aDefaultValue The value to return if the preference is not set.
  *
  * @return float  The value of the requested floating point preference.
  *
  * @see setCharPref
  */
 [optional_argc,binaryname(GetFloatPrefWithDefault)]
 float getFloatPref(in string aPrefName, [optional] in float aDefaultValue);
 [noscript,binaryname(GetFloatPref)]
 float getFloatPrefXPCOM(in string aPrefName);

 /**
  * Called to get the state of an individual ascii string preference.
  *
  * @param aPrefName The string preference to retrieve.
  * @param aDefaultValue The string to return if the preference is not set.
  *
  * @return ACString   The value of the requested string preference.
  *
  * @see setCharPref
  */
 [optional_argc,binaryname(GetCharPrefWithDefault)]
 ACString getCharPref(in string aPrefName,
                      [optional] in ACString aDefaultValue);
 [noscript,binaryname(GetCharPref)]
 ACString getCharPrefXPCOM(in string aPrefName);

 /**
  * Called to set the state of an individual ascii string preference.
  *
  * @param aPrefName The string preference to set.
  * @param aValue    The string value to set the preference to.
  *
  * @throws Error if setting failed or the preference has a default
            value of a type other than string.
  *
  * @see getCharPref
  */
 void setCharPref(in string aPrefName, in ACString aValue);

 /**
  * Called to get the state of an individual unicode string preference.
  *
  * @param aPrefName The string preference to retrieve.
  * @param aDefaultValue The string to return if the preference is not set.
  *
  * @return AUTF8String   The value of the requested string preference.
  *
  * @see setStringPref
  */
 [optional_argc]
 AUTF8String getStringPref(in string aPrefName,
                           [optional] in AUTF8String aDefaultValue);

 /**
  * Called to set the state of an individual unicode string preference.
  *
  * @param aPrefName The string preference to set.
  * @param aValue    The string value to set the preference to.
  *
  * @throws Error if setting failed or the preference has a default
            value of a type other than string.
  *
  * @see getStringPref
  */
 void setStringPref(in string aPrefName, in AUTF8String aValue);

 /**
  * Called to get the state of an individual integer preference.
  *
  * @param aPrefName The integer preference to get the value of.
  * @param aDefaultValue The value to return if the preference is not set.
  *
  * @return long     The value of the requested integer preference.
  *
  * @see setIntPref
  */
 [optional_argc,binaryname(GetIntPrefWithDefault)]
 long getIntPref(in string aPrefName, [optional] in long aDefaultValue);
 [noscript,binaryname(GetIntPref)]
 long getIntPrefXPCOM(in string aPrefName);

 /**
  * Called to set the state of an individual integer preference.
  *
  * @param aPrefName The integer preference to set the value of.
  * @param aValue    The integer value to set the preference to.
  *
  * @throws Error if setting failed or the preference has a default
            value of a type other than integer.
  *
  * @see getIntPref
  */
 void setIntPref(in string aPrefName, in long aValue);

 /**
  * Called to get the state of an individual complex preference. A complex
  * preference is a preference which represents an XPCOM object that can not
  * be easily represented using a standard boolean, integer or string value.
  *
  * @param aPrefName The complex preference to get the value of.
  * @param aType     The XPCOM interface that this complex preference
  *                  represents. Interfaces currently supported are:
  *                    - nsIFile
  *                    - nsIPrefLocalizedString (Localized UniChar)
  * @param aValue    The XPCOM object into which to the complex preference
  *                  value should be retrieved.
  *
  * @throws Error The value does not exist or is the wrong type.
  *
  * @see setComplexValue
  */
 void getComplexValue(in string aPrefName, in nsIIDRef aType,
                      [iid_is(aType), retval] out nsQIResult aValue);

 /**
  * Called to set the state of an individual complex preference. A complex
  * preference is a preference which represents an XPCOM object that can not
  * be easily represented using a standard boolean, integer or string value.
  *
  * @param aPrefName The complex preference to set the value of.
  * @param aType     The XPCOM interface that this complex preference
  *                  represents. Interfaces currently supported are:
  *                    - nsIFile
  *                    - nsISupportsString (UniChar)
  *                      (deprecated; see setStringPref)
  *                    - nsIPrefLocalizedString (Localized UniChar)
  * @param aValue    The XPCOM object from which to set the complex preference
  *                  value.
  *
  * @throws Error if setting failed or the value is the wrong type.
  *
  * @see getComplexValue
  */
 void setComplexValue(in string aPrefName, in nsIIDRef aType, in nsISupports aValue);

 /**
  * Called to clear a user set value from a specific preference. This will, in
  * effect, reset the value to the default value. If no default value exists
  * the preference will cease to exist.
  *
  * @param aPrefName The preference to be cleared.
  *
  * @note
  * This method does nothing if this object is a default branch.
  */
 void clearUserPref(in string aPrefName);

 /**
  * Called to lock a specific preference. Locking a preference will cause the
  * preference service to always return the default value regardless of
  * whether there is a user set value or not.
  *
  * @param aPrefName The preference to be locked.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on the default branch.
  *
  * @throws Error The preference does not exist or an error occurred.
  *
  * @see unlockPref
  */
 void lockPref(in string aPrefName);

 /**
  * Called to check if a specific preference has a user value associated to
  * it.
  *
  * @param aPrefName The preference to be tested.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on the user branch.
  *
  * @note
  * If a preference was manually set to a value that equals the default value,
  * then the preference no longer has a user set value, i.e. it is
  * considered reset to its default value.
  * In particular, this method will return false for such a preference and
  * the preference will not be saved to a file by nsIPrefService.savePrefFile.
  *
  * @return boolean  true  The preference has a user set value.
  *                  false The preference only has a default value.
  */
 boolean prefHasUserValue(in string aPrefName);

 /**
  * Called to check if a specific preference has a default value associated to
  * it.
  *
  * @param aPrefName The preference to be tested.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on the user branch.
  *
  * @note
  * This method can be used to distinguish between a built-in preference and a
  * user-added preference.
  *
  * @return boolean  true  The preference has a default value.
  *                  false The preference only has a user value.
  */
 boolean prefHasDefaultValue(in string aPrefName);

 /**
  * Called to check if a specific preference is locked. If a preference is
  * locked calling its Get method will always return the default value.
  *
  * @param aPrefName The preference to be tested.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on the default branch.
  *
  * @return boolean  true  The preference is locked.
  *                  false The preference is not locked.
  *
  * @see lockPref
  * @see unlockPref
  */
 boolean prefIsLocked(in string aPrefName);

 /**
  * Called to check if a specific preference has been sanitized. If a
  * preference is sanitized, any user value the preference may have will not
  * be present in a sub-process.  A preference is never sanitized in the
  * parent process; it is only marked as sanitized when it is converted
  * to a dom::Pref for serialization to a child process.
  *
  * @param aPrefName The preference to be tested.
  *
  * @note
  * This method can be called on either a default or user branch but it
  * makes no difference.
  *
  * @return boolean  true  The preference is sanitized.
  *                  false The preference is not sanitized.
  */
 boolean prefIsSanitized(in string aPrefName);

 /**
  * Called to unlock a specific preference. Unlocking a previously locked
  * preference allows the preference service to once again return the user set
  * value of the preference.
  *
  * @param aPrefName The preference to be unlocked.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on the default branch.
  *
  * @throws Error The preference does not exist or an error occurred.
  *
  * @see lockPref
  */
 void    unlockPref(in string aPrefName);


 /**
  * Called to remove all of the preferences referenced by this branch.
  *
  * @param aStartingAt The point on the branch at which to start the deleting
  *                    preferences. Pass in "" to remove all preferences
  *                    referenced by this branch.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on both.
  *
  * @throws Error The preference(s) do not exist or an error occurred.
  */
 void deleteBranch(in string aStartingAt);

 /**
  * Returns an array of strings representing the child preferences of the
  * root of this branch.
  *
  * @param aStartingAt The point on the branch at which to start enumerating
  *                    the child preferences. Pass in "" to enumerate all
  *                    preferences referenced by this branch.
  * @return            The array of child preferences.
  *
  * @note
  * This method can be called on either a default or user branch but, in
  * effect, always operates on both.
  *
  * @throws Error The preference(s) do not exist or an error occurred.
  */
 Array<ACString> getChildList(in string aStartingAt);

 /**
  * Add a preference change observer. On preference changes, the following
  * arguments will be passed to the nsIObserver.observe() method:
  *   aSubject - The nsIPrefBranch object (this)
  *   aTopic   - The string defined by NS_PREFBRANCH_PREFCHANGE_TOPIC_ID
  *   aData    - The name of the preference which has changed, relative to
  *              the |root| of the aSubject branch.
  *
  * aSubject.get*Pref(aData) will get the new value of the modified
  * preference. For example, if your observer is registered with
  * addObserver("bar.", ...) on a branch with root "foo.", modifying
  * the preference "foo.bar.baz" will trigger the observer, and aData
  * parameter will be "bar.baz".
  *
  * @param aDomain   The preference on which to listen for changes. This can
  *                  be the name of an entire branch to observe.
  *                  e.g. Holding the "root" prefbranch and calling
  *                  addObserver("foo.bar.", ...) will observe changes to
  *                  foo.bar.baz and foo.bar.bzip
  * @param aObserver The object to be notified if the preference changes.
  * @param aHoldWeak true  Hold a weak reference to |aObserver|. The object
  *                        must implement the nsISupportsWeakReference
  *                        interface or this will fail.
  *                  false Hold a strong reference to |aObserver|.
  *
  * @note
  * Registering as a preference observer can open an object to potential
  * cyclical references which will cause memory leaks. These cycles generally
  * occur because an object both registers itself as an observer (causing the
  * branch to hold a reference to the observer) and holds a reference to the
  * branch object for the purpose of getting/setting preference values. There
  * are 3 approaches which have been implemented in an attempt to avoid these
  * situations.
  * 1) The nsPrefBranch object supports nsISupportsWeakReference. Any consumer
  *    may hold a weak reference to it instead of a strong one.
  * 2) The nsPrefBranch object listens for xpcom-shutdown and frees all of the
  *    objects currently in its observer list. This ensures that long lived
  *    objects (services for example) will be freed correctly.
  * 3) The observer can request to be held as a weak reference when it is
  *    registered. This insures that shorter lived objects (say one tied to an
  *    open window) will not fall into the cyclical reference trap.
  *
  * @note
  * The list of registered observers may be changed during the dispatch of
  * nsPref:changed notification. However, the observers are not guaranteed
  * to be notified in any particular order, so you can't be sure whether the
  * added/removed observer will be called during the notification when it
  * is added/removed.
  *
  * @note
  * It is possible to change preferences during the notification.
  *
  * @note
  * It is not safe to change observers during this callback in Gecko
  * releases before 1.9. If you want a safe way to remove a pref observer,
  * please use an nsITimer.
  *
  * @see nsIObserver
  * @see removeObserver
  */
 [binaryname(AddObserverImpl)]
 void addObserver(in ACString aDomain, in nsIObserver aObserver,
                  [optional] in boolean aHoldWeak);

 /**
  * Remove a preference change observer.
  *
  * @param aDomain   The preference which is being observed for changes.
  * @param aObserver An observer previously registered with addObserver().
  *
  * @note
  * Note that you must call removeObserver() on the same nsIPrefBranch
  * instance on which you called addObserver() in order to remove aObserver;
  * otherwise, the observer will not be removed.
  *
  * @see nsIObserver
  * @see addObserver
  */
 [binaryname(RemoveObserverImpl)]
 void removeObserver(in ACString aDomain, in nsIObserver aObserver);

 %{C++
 nsresult AddObserver(const nsACString& aDomain, nsIObserver* aObserver,
                      bool aHoldWeak = false)
 {
   return AddObserverImpl(aDomain, aObserver, aHoldWeak);
 }

 template <int N>
 nsresult AddObserver(const char (&aDomain)[N], nsIObserver* aObserver,
                      bool aHoldWeak = false)
 {
   return AddObserverImpl(nsLiteralCString(aDomain), aObserver, aHoldWeak);
 }

 nsresult RemoveObserver(const nsACString& aDomain, nsIObserver* aObserver)
 {
   return RemoveObserverImpl(aDomain, aObserver);
 }

 template <int N>
 nsresult RemoveObserver(const char (&aDomain)[N], nsIObserver* aObserver)
 {
   return RemoveObserverImpl(nsLiteralCString(aDomain), aObserver);
 }
 %}
};


%{C++

/**
* Notification sent when a preference changes.
*/
#define NS_PREFBRANCH_PREFCHANGE_TOPIC_ID "nsPref:changed"

%}