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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.
#ifndef NET_HTTP_HTTP_CONNECTION_MANAGER_H_
#define NET_HTTP_HTTP_CONNECTION_MANAGER_H_
#include <deque>
#include <map>
#include "base/ref_counted.h"
#include "base/timer.h"
#include "net/base/completion_callback.h"
namespace net {
class ClientSocket;
// A HttpConnectionManager is used to restrict the number of HTTP sockets
// open at a time. It also maintains a list of idle persistent sockets.
//
// The HttpConnectionManager allocates SocketHandle objects, but it is not
// responsible for allocating the associated ClientSocket object. The
// consumer must do so if it gets a SocketHandle with a null ClientSocket.
//
class HttpConnectionManager : public base::RefCounted<HttpConnectionManager>,
public Task {
public:
HttpConnectionManager();
// The maximum number of simultaneous sockets per group.
enum { kMaxSocketsPerGroup = 6 };
typedef scoped_ptr<ClientSocket> SocketHandle;
// Called to get access to a SocketHandle object for the given group name.
//
// If this function returns OK, then |*handle| will reference a SocketHandle
// object. If ERR_IO_PENDING is returned, then the completion callback will
// be called when |*handle| has been populated. Otherwise, an error code is
// returned.
//
// If the resultant SocketHandle object has a null member, then it is the
// callers job to create a ClientSocket and associate it with the handle.
//
int RequestSocket(const std::string& group_name, SocketHandle** handle,
CompletionCallback* callback);
// Called to cancel a RequestSocket call that returned ERR_IO_PENDING. The
// same group_name and handle parameters must be passed to this method as
// were passed to the RequestSocket call being cancelled. The associated
// CompletionCallback is not run.
void CancelRequest(const std::string& group_name, SocketHandle** handle);
// Called to release a SocketHandle object that is no longer in use. If the
// handle has a ClientSocket that is still connected, then this handle may be
// added to the keep-alive set of sockets.
void ReleaseSocket(const std::string& group_name, SocketHandle* handle);
// Called to close any idle connections held by the connection manager.
void CloseIdleSockets();
private:
friend class base::RefCounted<HttpConnectionManager>;
~HttpConnectionManager();
// Closes all idle sockets if |only_if_disconnected| is false. Else, only
// idle sockets that are disconnected get closed.
void MaybeCloseIdleSockets(bool only_if_disconnected);
// Called when the number of idle sockets changes.
void IncrementIdleCount();
void DecrementIdleCount();
// Called via PostTask by ReleaseSocket.
void DoReleaseSocket(const std::string& group_name, SocketHandle* handle);
// Task implementation. This method scans the idle sockets checking to see
// if any have been disconnected.
virtual void Run();
// A Request is allocated per call to RequestSocket that results in
// ERR_IO_PENDING.
struct Request {
SocketHandle** result;
CompletionCallback* callback;
};
// A Group is allocated per group_name when there are idle sockets or pending
// requests. Otherwise, the Group object is removed from the map.
struct Group {
std::deque<SocketHandle*> idle_sockets;
std::deque<Request> pending_requests;
int active_socket_count;
Group() : active_socket_count(0) {}
};
typedef std::map<std::string, Group> GroupMap;
GroupMap group_map_;
// Timer used to periodically prune sockets that have been disconnected.
RepeatingTimer timer_;
// The total number of idle sockets in the system.
int idle_count_;
};
} // namespace net
#endif // NET_HTTP_HTTP_CONNECTION_MANAGER_H_
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