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Diffstat (limited to 'netwerk/cache/nsICache.idl')
| -rw-r--r-- | netwerk/cache/nsICache.idl | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/netwerk/cache/nsICache.idl b/netwerk/cache/nsICache.idl new file mode 100644 index 000000000..95bab1515 --- /dev/null +++ b/netwerk/cache/nsICache.idl @@ -0,0 +1,142 @@ +/* -*- 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; +}; + |