src/net/instaweb/util/public/http_cache.h

/**
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Author: jmarantz@google.com (Joshua Marantz)

#ifndef NET_INSTAWEB_UTIL_PUBLIC_HTTP_CACHE_H_
#define NET_INSTAWEB_UTIL_PUBLIC_HTTP_CACHE_H_

#include "base/basictypes.h"
#include "base/scoped_ptr.h"
#include "net/instaweb/util/public/cache_interface.h"
#include <string>
#include "net/instaweb/util/public/string_util.h"

namespace net_instaweb {

class CacheInterface;
class HTTPValue;
class MessageHandler;
class MetaData;
class Timer;

// Implements HTTP caching semantics, including cache expiration and
// retention of the originally served cache headers.
class HTTPCache {
 public:
  // Takes over ownership of the cache.
  HTTPCache(CacheInterface* cache, Timer* timer)
      : cache_(cache),
        timer_(timer),
        force_caching_(false) {
  }

  bool Get(const std::string& key, HTTPValue* value, MetaData* headers,
           MessageHandler* handler);

  // Note that Put takes a non-const pointer for HTTPValue so it can
  // bump the reference count.
  void Put(const std::string& key, HTTPValue* value, MessageHandler* handler);
  void Put(const std::string& key, const MetaData& headers,
           const StringPiece& content, MessageHandler* handler);

  CacheInterface::KeyState Query(const std::string& key);
  void Delete(const std::string& key);

  void set_force_caching(bool force) { force_caching_ = force; }
  bool force_caching() const { return force_caching_; }
  Timer* timer() const { return timer_; }

 private:
  bool IsCurrentlyValid(const MetaData& headers);

  scoped_ptr<CacheInterface> cache_;
  Timer* timer_;
  bool force_caching_;

  DISALLOW_COPY_AND_ASSIGN(HTTPCache);
};

}  // namespace net_instaweb

#endif  // NET_INSTAWEB_UTIL_PUBLIC_HTTP_CACHE_H_