gecko/netwerk/base/public/nsICachingChannel.idl

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 "nsICacheInfoChannel.idl"
interface nsIFile;
/**
* A channel may optionally implement this interface to allow clients
* to affect its behavior with respect to how it uses the cache service.
*
* This interface provides:
* 1) Support for "stream as file" semantics (for JAR and plugins).
* 2) Support for "pinning" cached data in the cache (for printing and save-as).
* 3) Support for uniquely identifying cached data in cases when the URL
* is insufficient (e.g., HTTP form submission).
*/
[scriptable, uuid(E2143B61-62FE-4da5-BE2E-E31981095889)]
interface nsICachingChannel : nsICacheInfoChannel
{
/**
* Set/get the cache token... uniquely identifies the data in the cache.
* Holding a reference to this token prevents the cached data from being
* removed.
*
* A cache token retrieved from a particular instance of nsICachingChannel
* could be set on another instance of nsICachingChannel provided the
* underlying implementations are compatible. The implementation of
* nsICachingChannel would be expected to only read from the cache entry
* identified by the cache token and not try to validate it.
*
* The cache token can be QI'd to a nsICacheEntryInfo if more detail
* about the cache entry is needed (e.g., expiration time).
*/
attribute nsISupports cacheToken;
/**
* The same as above but accessing the offline app cache token if there
* is any.
*
* @throws
* NS_ERROR_NOT_AVAILABLE when there is not offline cache token
*/
attribute nsISupports offlineCacheToken;
/**
* Set/get the cache key... uniquely identifies the data in the cache
* for this channel. Holding a reference to this key does NOT prevent
* the cached data from being removed.
*
* A cache key retrieved from a particular instance of nsICachingChannel
* could be set on another instance of nsICachingChannel provided the
* underlying implementations are compatible and provided the new
* channel instance was created with the same URI. The implementation of
* nsICachingChannel would be expected to use the cache entry identified
* by the cache token. Depending on the value of nsIRequest::loadFlags,
* the cache entry may be validated, overwritten, or simply read.
*
* The cache key may be NULL indicating that the URI of the channel is
* sufficient to locate the same cache entry. Setting a NULL cache key
* is likewise valid.
*/
attribute nsISupports cacheKey;
/**
* Specifies whether or not the data should be cached to a file. This
* may fail if the disk cache is not present. The value of this attribute
* is usually only settable during the processing of a channel's
* OnStartRequest. The default value of this attribute depends on the
* particular implementation of nsICachingChannel.
*/
attribute boolean cacheAsFile;
/**
* Specifies whether or not the data should be placed in the offline cache,
* in addition to normal memory/disk caching. This may fail if the offline
* cache is not present. The value of this attribute should be set before
* opening the channel.
*/
attribute boolean cacheForOfflineUse;
/**
* The session into which to cache offline data. If not specified,
* data will be placed in "HTTP-offline"
*/
attribute ACString offlineCacheClientID;
/**
* Override base (profile) directory to work with when accessing the cache.
* When not specified, the current process' profile directory will be used.
*/
attribute nsIFile profileDirectory;
/**
* Get the "file" where the cached data can be found. This is valid for
* as long as a reference to the cache token is held. This may return
* an error if cacheAsFile is false.
*/
readonly attribute nsIFile cacheFile;
/**************************************************************************
* Caching channel specific load flags:
*/
/**
* This load flag inhibits fetching from the net. An error of
* NS_ERROR_DOCUMENT_NOT_CACHED will be sent to the listener's
* onStopRequest if network IO is necessary to complete the request.
*
* This flag can be used to find out whether fetching this URL would
* cause validation of the cache entry via the network.
*
* Combining this flag with LOAD_BYPASS_LOCAL_CACHE will cause all
* loads to fail. This flag differs from LOAD_ONLY_FROM_CACHE in that
* this flag fails the load if validation is required while
* LOAD_ONLY_FROM_CACHE skips validation where possible.
*/
const unsigned long LOAD_NO_NETWORK_IO = 1 << 26;
/**
* This load flag causes the offline cache to be checked when fetching
* a request. It will be set automatically if the browser is offline.
*
* This flag will not be transferred through a redirect.
*/
const unsigned long LOAD_CHECK_OFFLINE_CACHE = 1 << 27;
/**
* This load flag causes the local cache to be skipped when fetching a
* request. Unlike LOAD_BYPASS_CACHE, it does not force an end-to-end load
* (i.e., it does not affect proxy caches).
*/
const unsigned long LOAD_BYPASS_LOCAL_CACHE = 1 << 28;
/**
* This load flag causes the local cache to be skipped if the request
* would otherwise block waiting to access the cache.
*/
const unsigned long LOAD_BYPASS_LOCAL_CACHE_IF_BUSY = 1 << 29;
/**
* This load flag inhibits fetching from the net if the data in the cache
* has been evicted. An error of NS_ERROR_DOCUMENT_NOT_CACHED will be sent
* to the listener's onStopRequest in this case. This flag is set
* automatically when the application is offline.
*/
const unsigned long LOAD_ONLY_FROM_CACHE = 1 << 30;
/**
* This load flag controls what happens when a document would be loaded
* from the cache to satisfy a call to AsyncOpen. If this attribute is
* set to TRUE, then the document will not be loaded from the cache. A
* stream listener can check nsICachingChannel::isFromCache to determine
* if the AsyncOpen will actually result in data being streamed.
*
* If this flag has been set, and the request can be satisfied via the
* cache, then the OnDataAvailable events will be skipped. The listener
* will only see OnStartRequest followed by OnStopRequest.
*/
const unsigned long LOAD_ONLY_IF_MODIFIED = 1 << 31;
};