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Diffstat (limited to 'modules/libpref/nsIPrefBranch.idl')
| -rw-r--r-- | modules/libpref/nsIPrefBranch.idl | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/modules/libpref/nsIPrefBranch.idl b/modules/libpref/nsIPrefBranch.idl new file mode 100644 index 000000000..ee0c11ef0 --- /dev/null +++ b/modules/libpref/nsIPrefBranch.idl @@ -0,0 +1,409 @@ +/* -*- 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" + +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, 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 string 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. + * + * @return boolean The value of the requested boolean preference. + * + * @see setBoolPref + */ + boolean getBoolPref(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. + * + * @return float The value of the requested floating point preference. + * + * @see setCharPref + */ + float getFloatPref(in string aPrefName); + + /** + * Called to get the state of an individual string preference. + * + * @param aPrefName The string preference to retrieve. + * + * @return string The value of the requested string preference. + * + * @see setCharPref + */ + string getCharPref(in string aPrefName); + + /** + * Called to set the state of an individual 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 string aValue); + + /** + * Called to get the state of an individual integer preference. + * + * @param aPrefName The integer preference to get the value of. + * + * @return long The value of the requested integer preference. + * + * @see setIntPref + */ + long getIntPref(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 + * - nsISupportsString (UniChar) + * - 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) + * - 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 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 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. + * @param aCount Receives the number of elements in the array. + * @param aChildArray Receives 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. + */ + void getChildList(in string aStartingAt, + [optional] out unsigned long aCount, + [array, size_is(aCount), retval] out string aChildArray); + + /** + * Called to reset all of the preferences referenced by this branch to their + * default values. + * + * @param aStartingAt The point on the branch at which to start the resetting + * preferences to their default values. Pass in "" to + * reset 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 the user branch. + * + * @throws Error The preference(s) do not exist or an error occurred. + */ + void resetBranch(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 + */ + void addObserver(in string aDomain, in nsIObserver aObserver, + 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 + */ + void removeObserver(in string aDomain, in nsIObserver aObserver); +}; + + +%{C++ + +#define NS_PREFBRANCH_CONTRACTID "@mozilla.org/preferencesbranch;1" +/** + * Notification sent when a preference changes. + */ +#define NS_PREFBRANCH_PREFCHANGE_TOPIC_ID "nsPref:changed" + +%} |