gecko-dev/netwerk/cache/public/nsIStreamAsFile.idl
2001-02-12 03:14:23 +00:00

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1999 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
* Scott Furman, fur@netscape.com
*/
#include "nsrootidl.idl"
#include "nsISupports.idl"
interface nsIFile;
interface nsIStreamAsFileObserver;
/**
* In addition to enhancing effective network response time via caching, the
* cache manager serves a second purpose by providing the stream-as-file
* service required by traditional browser plugins and the jar: protocol
* handler. The interface below provides a means for a client to determine the
* filename associated with a stream and to detect modification/deletion of
* that file.
*/
[scriptable, uuid(0eedbbf0-92d9-11d3-90d3-0040056a906e)]
interface nsIStreamAsFile : nsISupports
{
/**
* Filename containing stream-as-file
*/
readonly attribute nsIFile file;
/**
* Add an observer for this cache record. When the cache wants to delete
* or truncate a record, so as to make space for another cache entry's
* content data, it will call <code>aObserver</code>'s Observe() method,
* passing the nsIStreamAsFile instance as the <code>aSubject</code>
* argument and an appropriate message. If the observer does not wish to
* inhibit deletion/truncation, it should Release() any references it has to the
* cache record.
*
* @See nsIStreamAsFileObserver
*/
void addObserver(in nsIStreamAsFileObserver aObserver);
/**
* Delete an observer that was added by the AddObserver() method.
*/
void removeObserver(in nsIStreamAsFileObserver aObserver);
};
/**
* This interface can be implemented by a client to receive notifications of
* either modification or deletion of a file created by the cache manager using
* the stream-as-file semantics.
*/
[scriptable, uuid(a26e27c0-92da-11d3-90d3-0040056a906e)]
interface nsIStreamAsFileObserver : nsISupports
{
/**
* Flag bits for argument to observeStreamAsFile() method.
*/
const long NOTIFY_AVAILABLE = 1 << 0; // Stream-as-file now available for reading
const long NOTIFY_ERROR = 1 << 1; // Error while loading stream / creating file
const long REQUEST_DELETION = 1 << 2; // Cache manager wishes to delete/truncate file
const long INVALIDATE = 1 << 3; // File is out-of-date
// Convenience value
const long MAKE_UNAVAILABLE = REQUEST_DELETION | INVALIDATE;
/**
* Receive either a notification or a request concerning a file that has
* been opened using stream-as-file. The aMessage and aError arguments
* have varying values depending on the nature of the notification.
* aMessage is set to NOTIFY_AVAILABLE when a complete stream has been read
* and stored on disk in a file. At that point, and no sooner, may the
* filename attribute of the associated nsIStreamAsFile be accessed via the
* associated nsIStreamAsFile interface. If the aMessage argument is
* NOTIFY_ERROR, the aError argument contains the relevant error code. If
* the aMessage argument is either REQUEST_DELETION or REQUEST_TRUNCATION,
* the callee should immediately Release() all references to the
* nsIStreamAsFile (and any references to its associated nsICachedNetData
* instances), unless it wishes to inhibit the requested file modification.
* If the aMessage argument is INVALIDATE, the cache manager is replacing
* the file with a more recent version. If a client wants to continue
* using the (now out-of-date) file, it must delete it when it has finished,
* as the cache manager will effectively relinquished ownership of the
* file.
*/
void observeStreamAsFile(in nsIStreamAsFile aStreamAsFile,
in PRUint32 aMessage,
in nsresult aError);
};