gecko-dev/uriloader/exthandler/nsIHandlerService.idl
2012-05-21 12:12:37 +01:00

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/* 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 nsIHandlerInfo;
interface nsISimpleEnumerator;
[scriptable, uuid(53f0ad17-ec62-46a1-adbc-efccc06babcd)]
interface nsIHandlerService : nsISupports
{
/**
* Retrieve a list of all handlers in the datastore. This list is not
* guaranteed to be in any particular order, and callers should not assume
* it will remain in the same order in the future.
*
* @returns a list of all handlers in the datastore
*/
nsISimpleEnumerator enumerate();
/**
* Fill a handler info object with information from the datastore.
*
* Note: because of the way the external helper app service currently mixes
* OS and user handler info in the same handler info object, this method
* takes an existing handler info object (probably retrieved from the OS)
* and "fills it in" with information from the datastore, overriding any
* existing properties on the object with properties from the datastore.
*
* Ultimately, however, we're going to separate OS and user handler info
* into separate objects, at which point this method should be renamed to
* something like "get" or "retrieve", take a class and type (or perhaps
* a type whose class can be determined by querying the type, for example
* an nsIContentType which is also an nsIMIMEType or an nsIProtocolScheme),
* and return a handler info object representing only the user info.
*
* Note: if you specify an override type, then the service will fill in
* the handler info object with information about that type instead of
* the type specified by the object's nsIHandlerInfo::type attribute.
*
* This is useful when you are trying to retrieve information about a MIME
* type that doesn't exist in the datastore, but you have a file extension
* for that type, and nsIHandlerService::getTypeFromExtension returns another
* MIME type that does exist in the datastore and can handle that extension.
*
* For example, the user clicks on a link, and the content has a MIME type
* that isn't in the datastore, but the link has a file extension, and that
* extension is associated with another MIME type in the datastore (perhaps
* an unofficial MIME type preceded an official one, like with image/x-png
* and image/png).
*
* In that situation, you can call this method to fill in the handler info
* object with information about that other type by passing the other type
* as the aOverrideType parameter.
*
* @param aHandlerInfo the handler info object
* @param aOverrideType a type to use instead of aHandlerInfo::type
*
* Note: if there is no information in the datastore about this type,
* this method throws NS_ERROR_NOT_AVAILABLE. Callers are encouraged to
* check exists() before calling fillHandlerInfo(), to prevent spamming the
* console with XPCOM exception errors.
*/
void fillHandlerInfo(in nsIHandlerInfo aHandlerInfo,
in ACString aOverrideType);
/**
* Save the preferred action, preferred handler, possible handlers, and
* always ask properties of the given handler info object to the datastore.
* Updates an existing record or creates a new one if necessary.
*
* Note: if preferred action is undefined or invalid, then we assume
* the default value nsIHandlerInfo::useHelperApp.
*
* @param aHandlerInfo the handler info object
*/
void store(in nsIHandlerInfo aHandlerInfo);
/**
* Whether or not a record for the given handler info object exists
* in the datastore. If the datastore is corrupt (or some other error
* is caught in the implementation), false will be returned.
*
* @param aHandlerInfo a handler info object
*
* @returns whether or not a record exists
*/
boolean exists(in nsIHandlerInfo aHandlerInfo);
/**
* Remove the given handler info object from the datastore. Deletes all
* records associated with the object, including the preferred handler, info,
* and type records plus the entry in the list of types, if they exist.
* Otherwise, it does nothing and does not return an error.
*
* @param aHandlerInfo the handler info object
*/
void remove(in nsIHandlerInfo aHandlerInfo);
/**
* Get the MIME type mapped to the given file extension in the datastore.
*
* XXX If we ever support extension -> protocol scheme mappings, then this
* method should work for those as well.
*
* Note: in general, you should use nsIMIMEService::getTypeFromExtension
* to get a MIME type from a file extension, as that method checks a variety
* of other sources besides just the datastore. Use this only when you want
* to specifically get only the mapping available in the datastore.
*
* @param aFileExtension the file extension
*
* @returns the MIME type, if any; otherwise returns an empty string ("").
*/
ACString getTypeFromExtension(in ACString aFileExtension);
};