netwerk/cache/nsICache.idl@97036ab72558 (annotated)
netwerk/cache/nsICache.idl
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- |
| michael@0 | 2 | * |
| michael@0 | 3 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | #include "nsISupports.idl" |
| michael@0 | 8 | |
| michael@0 | 9 | typedef long nsCacheStoragePolicy; |
| michael@0 | 10 | typedef long nsCacheAccessMode; |
| michael@0 | 11 | |
| michael@0 | 12 | /** |
| michael@0 | 13 | * nsICache is a namespace for various cache constants. It does not represent |
| michael@0 | 14 | * an actual object. |
| michael@0 | 15 | */ |
| michael@0 | 16 | [scriptable, uuid(d6c67f38-b39a-4582-8a48-4c4f8a56dfd0)] |
| michael@0 | 17 | interface nsICache |
| michael@0 | 18 | { |
| michael@0 | 19 | /** |
| michael@0 | 20 | * Access Modes |
| michael@0 | 21 | * |
| michael@0 | 22 | * |
| michael@0 | 23 | * Mode Requested | Not Cached | Cached |
| michael@0 | 24 | * ------------------------------------------------------------------------ |
| michael@0 | 25 | * READ | KEY_NOT_FOUND | NS_OK |
| michael@0 | 26 | * | Mode = NONE | Mode = READ |
| michael@0 | 27 | * | No Descriptor | Descriptor |
| michael@0 | 28 | * ------------------------------------------------------------------------ |
| michael@0 | 29 | * WRITE | NS_OK | NS_OK (Cache service |
| michael@0 | 30 | * | Mode = WRITE | Mode = WRITE dooms existing |
| michael@0 | 31 | * | Descriptor | Descriptor cache entry) |
| michael@0 | 32 | * ------------------------------------------------------------------------ |
| michael@0 | 33 | * READ_WRITE | NS_OK | NS_OK |
| michael@0 | 34 | * (1st req.) | Mode = WRITE | Mode = READ_WRITE |
| michael@0 | 35 | * | Descriptor | Descriptor |
| michael@0 | 36 | * ------------------------------------------------------------------------ |
| michael@0 | 37 | * READ_WRITE | N/A | NS_OK |
| michael@0 | 38 | * (Nth req.) | | Mode = READ |
| michael@0 | 39 | * | | Descriptor |
| michael@0 | 40 | * ------------------------------------------------------------------------ |
| michael@0 | 41 | * |
| michael@0 | 42 | * |
| michael@0 | 43 | * Access Requested: |
| michael@0 | 44 | * |
| michael@0 | 45 | * READ - I only want to READ, if there isn't an entry just fail |
| michael@0 | 46 | * WRITE - I have something new I want to write into the cache, make |
| michael@0 | 47 | * me a new entry and doom the old one, if any. |
| michael@0 | 48 | * READ_WRITE - I want to READ, but I'm willing to update an existing |
| michael@0 | 49 | * entry if necessary, or create a new one if none exists. |
| michael@0 | 50 | * |
| michael@0 | 51 | * |
| michael@0 | 52 | * Access Granted: |
| michael@0 | 53 | * |
| michael@0 | 54 | * NONE - No descriptor is provided. You get zilch. Nada. Nothing. |
| michael@0 | 55 | * READ - You can READ from this descriptor. |
| michael@0 | 56 | * WRITE - You must WRITE to this descriptor because the cache entry |
| michael@0 | 57 | * was just created for you. |
| michael@0 | 58 | * READ_WRITE - You can READ the descriptor to determine if it's valid, |
| michael@0 | 59 | * you may WRITE if it needs updating. |
| michael@0 | 60 | * |
| michael@0 | 61 | * |
| michael@0 | 62 | * Comments: |
| michael@0 | 63 | * |
| michael@0 | 64 | * If you think that you might need to modify cached data or meta data, |
| michael@0 | 65 | * then you must open a cache entry requesting WRITE access. Only one |
| michael@0 | 66 | * cache entry descriptor, per cache entry, will be granted WRITE access. |
| michael@0 | 67 | * |
| michael@0 | 68 | * Usually, you will request READ_WRITE access in order to first test the |
| michael@0 | 69 | * meta data and informational fields to determine if a write (ie. going |
| michael@0 | 70 | * to the net) may actually be necessary. If you determine that it is |
| michael@0 | 71 | * not, then you would mark the cache entry as valid (using MarkValid) and |
| michael@0 | 72 | * then simply read the data from the cache. |
| michael@0 | 73 | * |
| michael@0 | 74 | * A descriptor granted WRITE access has exclusive access to the cache |
| michael@0 | 75 | * entry up to the point at which it marks it as valid. Once the cache |
| michael@0 | 76 | * entry has been "validated", other descriptors with READ access may be |
| michael@0 | 77 | * opened to the cache entry. |
| michael@0 | 78 | * |
| michael@0 | 79 | * If you make a request for READ_WRITE access to a cache entry, the cache |
| michael@0 | 80 | * service will downgrade your access to READ if there is already a |
| michael@0 | 81 | * cache entry descriptor open with WRITE access. |
| michael@0 | 82 | * |
| michael@0 | 83 | * If you make a request for only WRITE access to a cache entry and another |
| michael@0 | 84 | * descriptor with WRITE access is currently open, then the existing cache |
| michael@0 | 85 | * entry will be 'doomed', and you will be given a descriptor (with WRITE |
| michael@0 | 86 | * access only) to a new cache entry. |
| michael@0 | 87 | * |
| michael@0 | 88 | */ |
| michael@0 | 89 | const nsCacheAccessMode ACCESS_NONE = 0; |
| michael@0 | 90 | const nsCacheAccessMode ACCESS_READ = 1; |
| michael@0 | 91 | const nsCacheAccessMode ACCESS_WRITE = 2; |
| michael@0 | 92 | const nsCacheAccessMode ACCESS_READ_WRITE = 3; |
| michael@0 | 93 | |
| michael@0 | 94 | /** |
| michael@0 | 95 | * Storage Policy |
| michael@0 | 96 | * |
| michael@0 | 97 | * The storage policy of a cache entry determines the device(s) to which |
| michael@0 | 98 | * it belongs. See nsICacheSession and nsICacheEntryDescriptor for more |
| michael@0 | 99 | * details. |
| michael@0 | 100 | * |
| michael@0 | 101 | * STORE_ANYWHERE - Allows the cache entry to be stored in any device. |
| michael@0 | 102 | * The cache service decides which cache device to use |
| michael@0 | 103 | * based on "some resource management calculation." |
| michael@0 | 104 | * STORE_IN_MEMORY - Requires the cache entry to reside in non-persistent |
| michael@0 | 105 | * storage (ie. typically in system RAM). |
| michael@0 | 106 | * STORE_ON_DISK - Requires the cache entry to reside in persistent |
| michael@0 | 107 | * storage (ie. typically on a system's hard disk). |
| michael@0 | 108 | * STORE_OFFLINE - Requires the cache entry to reside in persistent, |
| michael@0 | 109 | * reliable storage for offline use. |
| michael@0 | 110 | */ |
| michael@0 | 111 | const nsCacheStoragePolicy STORE_ANYWHERE = 0; |
| michael@0 | 112 | const nsCacheStoragePolicy STORE_IN_MEMORY = 1; |
| michael@0 | 113 | const nsCacheStoragePolicy STORE_ON_DISK = 2; |
| michael@0 | 114 | // value 3 was used by STORE_ON_DISK_AS_FILE which was removed |
| michael@0 | 115 | const nsCacheStoragePolicy STORE_OFFLINE = 4; |
| michael@0 | 116 | |
| michael@0 | 117 | /** |
| michael@0 | 118 | * All entries for a cache session are stored as streams of data or |
| michael@0 | 119 | * as objects. These constant my be used to specify the type of entries |
| michael@0 | 120 | * when calling nsICacheService::CreateSession(). |
| michael@0 | 121 | */ |
| michael@0 | 122 | const long NOT_STREAM_BASED = 0; |
| michael@0 | 123 | const long STREAM_BASED = 1; |
| michael@0 | 124 | |
| michael@0 | 125 | /** |
| michael@0 | 126 | * The synchronous OpenCacheEntry() may be blocking or non-blocking. If a cache entry is |
| michael@0 | 127 | * waiting to be validated by another cache descriptor (so no new cache descriptors for that |
| michael@0 | 128 | * key can be created, OpenCacheEntry() will return NS_ERROR_CACHE_WAIT_FOR_VALIDATION in |
| michael@0 | 129 | * non-blocking mode. In blocking mode, it will wait until the cache entry for the key has |
| michael@0 | 130 | * been validated or doomed. If the cache entry is validated, then a descriptor for that |
| michael@0 | 131 | * entry will be created and returned. If the cache entry was doomed, then a descriptor |
| michael@0 | 132 | * will be created for a new cache entry for the key. |
| michael@0 | 133 | */ |
| michael@0 | 134 | const long NON_BLOCKING = 0; |
| michael@0 | 135 | const long BLOCKING = 1; |
| michael@0 | 136 | |
| michael@0 | 137 | /** |
| michael@0 | 138 | * Constant meaning no expiration time. |
| michael@0 | 139 | */ |
| michael@0 | 140 | const unsigned long NO_EXPIRATION_TIME = 0xFFFFFFFF; |
| michael@0 | 141 | }; |
| michael@0 | 142 |
