URLRequestContext and disk cache for media files

net/http/http_cache.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file declares a HttpTransactionFactory implementation that can be
 // layered on top of another HttpTransactionFactory to add HTTP caching.  The
 // caching logic follows RFC 2616 (any exceptions are called out in the code).
 //
 // The HttpCache takes a disk_cache::Backend as a parameter, and uses that for
 // the cache storage.
@@ skipping 11 matching lines @@
 #include "base/task.h"
 #include "net/http/http_transaction_factory.h"
 
 namespace disk_cache {
 class Backend;
 class Entry;
 }
 
 namespace net {
 
+class HttpNetworkSession;
 class HttpRequestInfo;
 class HttpResponseInfo;
 class ProxyService;
 
 class HttpCache : public HttpTransactionFactory {
  public:
   ~HttpCache();
 
   // The cache mode of operation.
   enum Mode {
     // Normal mode just behaves like a standard web cache.
     NORMAL = 0,
     // Record mode caches everything for purposes of offline playback.
     RECORD,
     // Playback mode replays from a cache without considering any
     // standard invalidations.
     PLAYBACK
   };
 
-  // Initialize the cache from the directory where its data is stored.  The
+  // The type of an HttpCache object, essentially describe what an HttpCache
+  // object is for.
+  enum Type {
+    // An HttpCache object for common objects, e.g. html pages, images, fonts,
+    // css files, js files and other common web resources.
+    COMMON = 0,
+    // A cache system for media file, e.g. video and audio files. These files
+    // are huge and has special requirement for access.
+    MEDIA
+  };
+
+  // Initialize the cache from the directory where its data is stored. The
   // disk cache is initialized lazily (by CreateTransaction) in this case. If
   // |cache_size| is zero, a default value will be calculated automatically.
   HttpCache(ProxyService* proxy_service,
             const std::wstring& cache_dir,
             int cache_size);
 
+  // Initialize the cache from the directory where its data is stored. The
+  // disk cache is initialized lazily (by CreateTransaction) in  this case. If
+  // |cache_size| is zero, a default value will be calculated automatically.
+  // Provide an existing HttpNetworkSession, the cache can construct a
+  // network layer with a shared HttpNetworkSession in order for multiple
+  // network layers to share information (e.g. authenication data).
+  HttpCache(HttpNetworkSession* session, const std::wstring& cache_dir,
+            int cache_size);
+
   // Initialize using an in-memory cache. The cache is initialized lazily
   // (by CreateTransaction) in this case. If |cache_size| is zero, a default
   // value will be calculated automatically.
   HttpCache(ProxyService* proxy_service, int cache_size);
 
   // Initialize the cache from its component parts, which is useful for
   // testing.  The lifetime of the network_layer and disk_cache are managed by
   // the HttpCache and will be destroyed using |delete| when the HttpCache is
   // destroyed.
   HttpCache(HttpTransactionFactory* network_layer,
@@ skipping 16 matching lines @@
                                 const HttpResponseInfo* response_info,
                                 bool skip_transient_headers);
 
   // Generate a key that can be used inside the cache.
   std::string GenerateCacheKey(const HttpRequestInfo* request);
 
   // Get/Set the cache's mode.
   void set_mode(Mode value) { mode_ = value; }
   Mode mode() { return mode_; }
 
+  void set_type(Type type) { type_ = type; }
+  Type type() { return type_; }
+
  private:
 
   // Types --------------------------------------------------------------------
 
   class Transaction;
   friend class Transaction;
 
   typedef std::list<Transaction*> TransactionList;
 
   struct ActiveEntry {
@@ skipping 35 matching lines @@
 
   void OnProcessPendingQueue(ActiveEntry* entry);
 
 
   // Variables ----------------------------------------------------------------
 
   // used when lazily constructing the disk_cache_
   std::wstring disk_cache_dir_;
 
   Mode mode_;
+  Type type_;
 
   scoped_ptr<HttpTransactionFactory> network_layer_;
   scoped_ptr<disk_cache::Backend> disk_cache_;
 
   // The set of active entries indexed by cache key
   ActiveEntriesMap active_entries_;
 
   // The set of doomed entries
   ActiveEntriesSet doomed_entries_;
 
   ScopedRunnableMethodFactory<HttpCache> task_factory_;
 
   bool in_memory_cache_;
   int cache_size_;
 
   typedef base::hash_map<std::string, int> PlaybackCacheMap;
   scoped_ptr<PlaybackCacheMap> playback_cache_map_;
 
   RevocableStore transactions_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpCache);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_H_