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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 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.
//
// See HttpTransactionFactory and HttpTransaction for more details.
#ifndef NET_HTTP_HTTP_CACHE_H__
#define NET_HTTP_HTTP_CACHE_H__
#include <hash_map>
#include <hash_set>
#include <list>
#include <string>
#include "base/basictypes.h"
#include "base/task.h"
#include "net/http/http_transaction_factory.h"
namespace disk_cache {
class Backend;
class Entry;
}
namespace net {
class HttpProxyInfo;
class HttpRequestInfo;
class HttpResponseInfo;
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
// disk cache is initialized lazily (by CreateTransaction) in this case. If
// |cache_size| is zero, a default value will be calculated automatically.
// If the proxy information is null, then the system settings will be used.
HttpCache(const HttpProxyInfo* proxy_info,
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. If the proxy information is null,
// then the system settings will be used.
HttpCache(const HttpProxyInfo* proxy_info, 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,
disk_cache::Backend* disk_cache);
HttpTransactionFactory* network_layer() { return network_layer_.get(); }
disk_cache::Backend* disk_cache() { return disk_cache_.get(); }
// HttpTransactionFactory implementation:
virtual HttpTransaction* CreateTransaction();
virtual HttpCache* GetCache();
virtual AuthCache* GetAuthCache();
virtual void Suspend(bool suspend);
// Helper function for reading response info from the disk cache.
static bool ReadResponseInfo(disk_cache::Entry* disk_entry,
HttpResponseInfo* response_info);
// Helper function for writing response info into the disk cache.
static bool WriteResponseInfo(disk_cache::Entry* disk_entry,
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_; }
private:
// Types --------------------------------------------------------------------
class Transaction;
friend Transaction;
typedef std::list<Transaction*> TransactionList;
struct ActiveEntry {
disk_cache::Entry* disk_entry;
Transaction* writer;
TransactionList readers;
TransactionList pending_queue;
bool will_process_pending_queue;
bool doomed;
explicit ActiveEntry(disk_cache::Entry*);
~ActiveEntry();
};
typedef stdext::hash_map<std::string, ActiveEntry*> ActiveEntriesMap;
typedef stdext::hash_set<ActiveEntry*> ActiveEntriesSet;
// Methods ------------------------------------------------------------------
void DoomEntry(const std::string& key);
void FinalizeDoomedEntry(ActiveEntry* entry);
ActiveEntry* FindActiveEntry(const std::string& key);
ActiveEntry* ActivateEntry(const std::string& key, disk_cache::Entry*);
void DeactivateEntry(ActiveEntry* entry);
ActiveEntry* OpenEntry(const std::string& key);
ActiveEntry* CreateEntry(const std::string& cache_key);
void DestroyEntry(ActiveEntry* entry);
int AddTransactionToEntry(ActiveEntry* entry, Transaction* trans);
void DoneWritingToEntry(ActiveEntry* entry, bool success);
void DoneReadingFromEntry(ActiveEntry* entry, Transaction* trans);
void ConvertWriterToReader(ActiveEntry* entry);
void RemovePendingTransaction(Transaction* trans);
void ProcessPendingQueue(ActiveEntry* entry);
// Events (called via PostTask) ---------------------------------------------
void OnProcessPendingQueue(ActiveEntry* entry);
// Variables ----------------------------------------------------------------
// used when lazily constructing the disk_cache_
std::wstring disk_cache_dir_;
Mode mode_;
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 stdext::hash_map<std::string, int> PlaybackCacheMap;
scoped_ptr<PlaybackCacheMap> playback_cache_map_;
DISALLOW_EVIL_CONSTRUCTORS(HttpCache);
};
} // namespace net
#endif // NET_HTTP_HTTP_CACHE_H__
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