/* -*- Mode: IDL; 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 "nsISupports.idl" typedef long nsCacheStoragePolicy; typedef long nsCacheAccessMode; /** * nsICache is a namespace for various cache constants. It does not represent * an actual object. */ [scriptable, uuid(d6c67f38-b39a-4582-8a48-4c4f8a56dfd0)] interface nsICache { /** * Access Modes * * * Mode Requested | Not Cached | Cached * ------------------------------------------------------------------------ * READ | KEY_NOT_FOUND | NS_OK * | Mode = NONE | Mode = READ * | No Descriptor | Descriptor * ------------------------------------------------------------------------ * WRITE | NS_OK | NS_OK (Cache service * | Mode = WRITE | Mode = WRITE dooms existing * | Descriptor | Descriptor cache entry) * ------------------------------------------------------------------------ * READ_WRITE | NS_OK | NS_OK * (1st req.) | Mode = WRITE | Mode = READ_WRITE * | Descriptor | Descriptor * ------------------------------------------------------------------------ * READ_WRITE | N/A | NS_OK * (Nth req.) | | Mode = READ * | | Descriptor * ------------------------------------------------------------------------ * * * Access Requested: * * READ - I only want to READ, if there isn't an entry just fail * WRITE - I have something new I want to write into the cache, make * me a new entry and doom the old one, if any. * READ_WRITE - I want to READ, but I'm willing to update an existing * entry if necessary, or create a new one if none exists. * * * Access Granted: * * NONE - No descriptor is provided. You get zilch. Nada. Nothing. * READ - You can READ from this descriptor. * WRITE - You must WRITE to this descriptor because the cache entry * was just created for you. * READ_WRITE - You can READ the descriptor to determine if it's valid, * you may WRITE if it needs updating. * * * Comments: * * If you think that you might need to modify cached data or meta data, * then you must open a cache entry requesting WRITE access. Only one * cache entry descriptor, per cache entry, will be granted WRITE access. * * Usually, you will request READ_WRITE access in order to first test the * meta data and informational fields to determine if a write (ie. going * to the net) may actually be necessary. If you determine that it is * not, then you would mark the cache entry as valid (using MarkValid) and * then simply read the data from the cache. * * A descriptor granted WRITE access has exclusive access to the cache * entry up to the point at which it marks it as valid. Once the cache * entry has been "validated", other descriptors with READ access may be * opened to the cache entry. * * If you make a request for READ_WRITE access to a cache entry, the cache * service will downgrade your access to READ if there is already a * cache entry descriptor open with WRITE access. * * If you make a request for only WRITE access to a cache entry and another * descriptor with WRITE access is currently open, then the existing cache * entry will be 'doomed', and you will be given a descriptor (with WRITE * access only) to a new cache entry. * */ const nsCacheAccessMode ACCESS_NONE = 0; const nsCacheAccessMode ACCESS_READ = 1; const nsCacheAccessMode ACCESS_WRITE = 2; const nsCacheAccessMode ACCESS_READ_WRITE = 3; /** * Storage Policy * * The storage policy of a cache entry determines the device(s) to which * it belongs. See nsICacheSession and nsICacheEntryDescriptor for more * details. * * STORE_ANYWHERE - Allows the cache entry to be stored in any device. * The cache service decides which cache device to use * based on "some resource management calculation." * STORE_IN_MEMORY - Requires the cache entry to reside in non-persistent * storage (ie. typically in system RAM). * STORE_ON_DISK - Requires the cache entry to reside in persistent * storage (ie. typically on a system's hard disk). * STORE_OFFLINE - Requires the cache entry to reside in persistent, * reliable storage for offline use. */ const nsCacheStoragePolicy STORE_ANYWHERE = 0; const nsCacheStoragePolicy STORE_IN_MEMORY = 1; const nsCacheStoragePolicy STORE_ON_DISK = 2; // value 3 was used by STORE_ON_DISK_AS_FILE which was removed const nsCacheStoragePolicy STORE_OFFLINE = 4; /** * All entries for a cache session are stored as streams of data or * as objects. These constant my be used to specify the type of entries * when calling nsICacheService::CreateSession(). */ const long NOT_STREAM_BASED = 0; const long STREAM_BASED = 1; /** * The synchronous OpenCacheEntry() may be blocking or non-blocking. If a cache entry is * waiting to be validated by another cache descriptor (so no new cache descriptors for that * key can be created, OpenCacheEntry() will return NS_ERROR_CACHE_WAIT_FOR_VALIDATION in * non-blocking mode. In blocking mode, it will wait until the cache entry for the key has * been validated or doomed. If the cache entry is validated, then a descriptor for that * entry will be created and returned. If the cache entry was doomed, then a descriptor * will be created for a new cache entry for the key. */ const long NON_BLOCKING = 0; const long BLOCKING = 1; /** * Constant meaning no expiration time. */ const unsigned long NO_EXPIRATION_TIME = 0xFFFFFFFF; };