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// 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.
#ifndef NET_BASE_CLIENT_SOCKET_POOL_H_
#define NET_BASE_CLIENT_SOCKET_POOL_H_
#include <deque>
#include <map>
#include <string>
#include "base/ref_counted.h"
#include "base/timer.h"
#include "net/base/completion_callback.h"
namespace net {
class ClientSocket;
class ClientSocketHandle;
// A ClientSocketPool is used to restrict the number of sockets open at a time.
// It also maintains a list of idle persistent sockets.
//
// The ClientSocketPool allocates scoped_ptr<ClientSocket> objects, but it is
// not responsible for allocating the associated ClientSocket objects. The
// consumer must do so if it gets a scoped_ptr<ClientSocket> with a null value.
//
class ClientSocketPool : public base::RefCounted<ClientSocketPool> {
public:
explicit ClientSocketPool(int max_sockets_per_group);
// Called to request a socket for the given handle. There are three possible
// results: 1) the handle will be initialized with a socket to reuse, 2) the
// handle will be initialized without a socket such that the consumer needs
// to supply a socket, or 3) the handle will be added to a wait list until a
// socket is available to reuse or the opportunity to create a new socket
// arises. The completion callback is notified in the 3rd case.
//
// If this function returns OK, then |handle| is initialized upon return.
// The |handle|'s is_initialized method will return true in this case. If a
// ClientSocket was reused, then |handle|'s socket member will be non-NULL.
// Otherwise, the consumer will need to supply |handle| with a socket by
// allocating a new ClientSocket object and calling the |handle|'s set_socket
// method.
//
// If ERR_IO_PENDING is returned, then the completion callback will be called
// when |handle| has been initialized.
//
int RequestSocket(ClientSocketHandle* handle, CompletionCallback* callback);
// Called to cancel a RequestSocket call that returned ERR_IO_PENDING. The
// same handle parameter must be passed to this method as was passed to the
// RequestSocket call being cancelled. The associated CompletionCallback is
// not run.
void CancelRequest(ClientSocketHandle* handle);
// Called to release the socket member of an initialized ClientSocketHandle
// once the socket is no longer needed. If the socket member is non-null and
// still has an established connection, then it will be added to the idle set
// of sockets to be used to satisfy future RequestSocket calls. Otherwise,
// the ClientSocket is destroyed.
void ReleaseSocket(ClientSocketHandle* handle);
// Called to close any idle connections held by the connection manager.
void CloseIdleSockets();
// The total number of idle sockets in the pool.
int idle_socket_count() const {
return idle_socket_count_;
}
private:
friend class base::RefCounted<ClientSocketPool>;
typedef scoped_ptr<ClientSocket> ClientSocketPtr;
~ClientSocketPool();
// Closes all idle sockets if |force| is true. Else, only closes idle
// sockets that timed out or can't be reused.
void CleanupIdleSockets(bool force);
// Called when the number of idle sockets changes.
void IncrementIdleCount();
void DecrementIdleCount();
// Called via PostTask by ReleaseSocket.
void DoReleaseSocket(const std::string& group_name, ClientSocketPtr* ptr);
// Called when timer_ fires. This method scans the idle sockets removing
// sockets that timed out or can't be reused.
void OnCleanupTimerFired() {
CleanupIdleSockets(false);
}
// A Request is allocated per call to RequestSocket that results in
// ERR_IO_PENDING.
struct Request {
ClientSocketHandle* handle;
CompletionCallback* callback;
};
// Entry for a persistent socket which became idle at time |start_time|.
struct IdleSocket {
ClientSocketPtr* ptr;
base::TimeTicks start_time;
// An idle socket should be removed if it can't be reused, or has been idle
// for too long. |now| is the current time value (TimeTicks::Now()).
//
// An idle socket can't be reused if it is disconnected or has received
// data unexpectedly (hence no longer idle). The unread data would be
// mistaken for the beginning of the next response if we were to reuse the
// socket for a new request.
bool ShouldCleanup(base::TimeTicks now) const;
};
// 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 {
Group() : active_socket_count(0) {}
std::deque<IdleSocket> idle_sockets;
std::deque<Request> pending_requests;
int active_socket_count;
};
typedef std::map<std::string, Group> GroupMap;
GroupMap group_map_;
// Timer used to periodically prune idle sockets that timed out or can't be
// reused.
base::RepeatingTimer<ClientSocketPool> timer_;
// The total number of idle sockets in the system.
int idle_socket_count_;
// The maximum number of sockets kept per group.
int max_sockets_per_group_;
DISALLOW_COPY_AND_ASSIGN(ClientSocketPool);
};
} // namespace net
#endif // NET_BASE_CLIENT_SOCKET_POOL_H_
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