async_fetch_with_lock.h

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/*
 * Copyright 2013 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.
 */



#ifndef NET_INSTAWEB_HTTP_PUBLIC_ASYNC_FETCH_WITH_LOCK_H_
#define NET_INSTAWEB_HTTP_PUBLIC_ASYNC_FETCH_WITH_LOCK_H_

#include "net/instaweb/http/public/async_fetch.h"
#include "net/instaweb/http/public/request_context.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

class Hasher;
class MessageHandler;
class NamedLock;
class NamedLockManager;
class UrlAsyncFetcher;

class AsyncFetchWithLock : public AsyncFetch {
 public:
  AsyncFetchWithLock(const Hasher* hasher,
                     const RequestContextPtr& request_context,
                     const GoogleString& url,
                     const GoogleString& cache_key,
                     NamedLockManager* lock_manager,
                     MessageHandler* message_handler);
  virtual ~AsyncFetchWithLock();

  void Start(UrlAsyncFetcher* fetcher);

  const GoogleString& url() const { return url_; }

  const GoogleString& cache_key() const { return cache_key_; }

 protected:
  virtual bool ShouldYieldToRedundantFetchInProgress() = 0;

  virtual void Finalize(bool lock_failure, bool success);

  virtual void StartFetch(
     UrlAsyncFetcher* fetcher, MessageHandler* handler) = 0;

  virtual void HandleDone(bool success);

  virtual void HandleHeadersComplete();
  virtual bool HandleWrite(
      const StringPiece& content, MessageHandler* handler);
  virtual bool HandleFlush(MessageHandler* handler);

 private:
  NamedLock* MakeInputLock(const GoogleString& url);
  static NamedLock* MakeInputLock(const GoogleString& url,
                                  const Hasher* hasher,
                                  NamedLockManager* lock_manager);

  void LockFailed(UrlAsyncFetcher* fetcher);
  void LockAcquired(UrlAsyncFetcher* fetcher);

  NamedLockManager* lock_manager_; 
  scoped_ptr<NamedLock> lock_;
  const Hasher* lock_hasher_; 
  GoogleString url_;
  GoogleString cache_key_;
  MessageHandler* message_handler_;

  friend class RewriteContextTest;

  
};

}  

#endif