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/* -*- 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
#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.
*
* @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"
%}