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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_SOCKET_CLIENT_SOCKET_POOL_BASE_H_
#define NET_SOCKET_CLIENT_SOCKET_POOL_BASE_H_
#include <deque>
#include <map>
#include <set>
#include <string>
#include "base/basictypes.h"
#include "base/scoped_ptr.h"
#include "base/time.h"
#include "base/timer.h"
#include "net/base/address_list.h"
#include "net/base/completion_callback.h"
#include "net/base/host_resolver.h"
#include "net/base/load_log.h"
#include "net/base/load_states.h"
#include "net/socket/client_socket.h"
#include "net/socket/client_socket_pool.h"
namespace net {
class ClientSocketHandle;
class ClientSocketPoolBase;
// ConnectJob provides an abstract interface for "connecting" a socket.
// The connection may involve host resolution, tcp connection, ssl connection,
// etc.
class ConnectJob {
public:
class Delegate {
public:
Delegate() {}
virtual ~Delegate() {}
// Alerts the delegate that the connection completed.
virtual void OnConnectJobComplete(int result, ConnectJob* job) = 0;
private:
DISALLOW_COPY_AND_ASSIGN(Delegate);
};
// A |timeout_duration| of 0 corresponds to no timeout.
ConnectJob(const std::string& group_name,
const ClientSocketHandle* key_handle,
base::TimeDelta timeout_duration,
Delegate* delegate);
virtual ~ConnectJob();
// Accessors
const std::string& group_name() const { return group_name_; }
LoadState load_state() const { return load_state_; }
const ClientSocketHandle* key_handle() const { return key_handle_; }
// Releases |socket_| to the client. On connection error, this should return
// NULL.
ClientSocket* ReleaseSocket() { return socket_.release(); }
// Begins connecting the socket. Returns OK on success, ERR_IO_PENDING if it
// cannot complete synchronously without blocking, or another net error code
// on error. In asynchronous completion, the ConnectJob will notify
// |delegate_| via OnConnectJobComplete. In both asynchronous and synchronous
// completion, ReleaseSocket() can be called to acquire the connected socket
// if it succeeded.
int Connect();
protected:
void set_load_state(LoadState load_state) { load_state_ = load_state; }
void set_socket(ClientSocket* socket) { socket_.reset(socket); }
ClientSocket* socket() { return socket_.get(); }
Delegate* delegate() { return delegate_; }
private:
virtual int ConnectInternal() = 0;
// Alerts the delegate that the ConnectJob has timed out.
void OnTimeout();
const std::string group_name_;
// Temporarily needed until we switch to late binding.
const ClientSocketHandle* const key_handle_;
const base::TimeDelta timeout_duration_;
// Timer to abort jobs that take too long.
base::OneShotTimer<ConnectJob> timer_;
Delegate* delegate_;
LoadState load_state_;
scoped_ptr<ClientSocket> socket_;
DISALLOW_COPY_AND_ASSIGN(ConnectJob);
};
// A ClientSocketPoolBase is used to restrict the number of sockets open at
// a time. It also maintains a list of idle persistent sockets.
//
class ClientSocketPoolBase
: public base::RefCounted<ClientSocketPoolBase>,
public ConnectJob::Delegate {
public:
// A Request is allocated per call to RequestSocket that results in
// ERR_IO_PENDING.
struct Request {
// HostResolver::RequestInfo has no default constructor, so fudge something.
Request()
: handle(NULL),
callback(NULL),
priority(0),
resolve_info(std::string(), 0) {}
Request(LoadLog* load_log,
ClientSocketHandle* handle,
CompletionCallback* callback,
int priority,
const HostResolver::RequestInfo& resolve_info)
: load_log(load_log), handle(handle), callback(callback),
priority(priority), resolve_info(resolve_info) {
}
scoped_refptr<LoadLog> load_log;
ClientSocketHandle* handle;
CompletionCallback* callback;
int priority;
HostResolver::RequestInfo resolve_info;
};
class ConnectJobFactory {
public:
ConnectJobFactory() {}
virtual ~ConnectJobFactory() {}
virtual ConnectJob* NewConnectJob(
const std::string& group_name,
const Request& request,
ConnectJob::Delegate* delegate) const = 0;
private:
DISALLOW_COPY_AND_ASSIGN(ConnectJobFactory);
};
ClientSocketPoolBase(int max_sockets,
int max_sockets_per_group,
ConnectJobFactory* connect_job_factory);
~ClientSocketPoolBase();
int RequestSocket(LoadLog* load_log,
const std::string& group_name,
const HostResolver::RequestInfo& resolve_info,
int priority,
ClientSocketHandle* handle,
CompletionCallback* callback);
void CancelRequest(const std::string& group_name,
const ClientSocketHandle* handle);
void ReleaseSocket(const std::string& group_name,
ClientSocket* socket);
void CloseIdleSockets();
int idle_socket_count() const {
return idle_socket_count_;
}
int IdleSocketCountInGroup(const std::string& group_name) const;
LoadState GetLoadState(const std::string& group_name,
const ClientSocketHandle* handle) const;
virtual void OnConnectJobComplete(int result, ConnectJob* job);
// Enables late binding of sockets. In this mode, socket requests are
// decoupled from socket connection jobs. A socket request may initiate a
// socket connection job, but there is no guarantee that that socket
// connection will service the request (for example, a released socket may
// service the request sooner, or a higher priority request may come in
// afterward and receive the socket from the job).
static void EnableLateBindingOfSockets(bool enabled);
// For testing.
bool may_have_stalled_group() const { return may_have_stalled_group_; }
int NumConnectJobsInGroup(const std::string& group_name) const {
return group_map_.find(group_name)->second.jobs.size();
}
private:
// Entry for a persistent socket which became idle at time |start_time|.
struct IdleSocket {
IdleSocket() : socket(NULL), used(false) {}
ClientSocket* socket;
base::TimeTicks start_time;
bool used; // Indicates whether or not the socket has been used yet.
// 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;
};
typedef std::deque<Request> RequestQueue;
typedef std::map<const ClientSocketHandle*, Request> RequestMap;
// 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) {}
bool IsEmpty() const {
return active_socket_count == 0 && idle_sockets.empty() && jobs.empty() &&
pending_requests.empty() && connecting_requests.empty();
}
bool HasAvailableSocketSlot(int max_sockets_per_group) const {
return active_socket_count + static_cast<int>(jobs.size()) <
max_sockets_per_group;
}
int TopPendingPriority() const {
return pending_requests.front().priority;
}
std::deque<IdleSocket> idle_sockets;
std::set<const ConnectJob*> jobs;
RequestQueue pending_requests;
RequestMap connecting_requests;
int active_socket_count; // number of active sockets used by clients
};
typedef std::map<std::string, Group> GroupMap;
typedef std::map<const ClientSocketHandle*, ConnectJob*> ConnectJobMap;
typedef std::set<const ConnectJob*> ConnectJobSet;
static void InsertRequestIntoQueue(const Request& r,
RequestQueue* pending_requests);
// 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, ClientSocket* socket);
// Scans the group map for groups which have an available socket slot and
// at least one pending request. Returns number of groups found, and if found
// at least one, fills |group| and |group_name| with data of the stalled group
// having highest priority.
int FindTopStalledGroup(Group** group, std::string* group_name);
// Called when timer_ fires. This method scans the idle sockets removing
// sockets that timed out or can't be reused.
void OnCleanupTimerFired() {
CleanupIdleSockets(false);
}
// Removes the ConnectJob corresponding to |handle| from the
// |connect_job_map_| or |connect_job_set_| depending on whether or not late
// binding is enabled. |job| must be non-NULL when late binding is
// enabled. Also updates |group| if non-NULL.
void RemoveConnectJob(const ClientSocketHandle* handle,
const ConnectJob* job,
Group* group);
// Same as OnAvailableSocketSlot except it looks up the Group first to see if
// it's there.
void MaybeOnAvailableSocketSlot(const std::string& group_name);
// Might delete the Group from |group_map_|.
void OnAvailableSocketSlot(const std::string& group_name, Group* group);
// Process a request from a group's pending_requests queue.
void ProcessPendingRequest(const std::string& group_name, Group* group);
// Assigns |socket| to |handle| and updates |group|'s counters appropriately.
void HandOutSocket(ClientSocket* socket,
bool reused,
ClientSocketHandle* handle,
Group* group);
// Adds |socket| to the list of idle sockets for |group|. |used| indicates
// whether or not the socket has previously been used.
void AddIdleSocket(ClientSocket* socket, bool used, Group* group);
// Iterates through |connect_job_map_|, canceling all ConnectJobs.
// Afterwards, it iterates through all groups and deletes them if they are no
// longer needed.
void CancelAllConnectJobs();
// Returns true if we can't create any more sockets due to the total limit.
// TODO(phajdan.jr): Also take idle sockets into account.
bool ReachedMaxSocketsLimit() const;
GroupMap group_map_;
ConnectJobMap connect_job_map_;
// Timer used to periodically prune idle sockets that timed out or can't be
// reused.
base::RepeatingTimer<ClientSocketPoolBase> timer_;
// The total number of idle sockets in the system.
int idle_socket_count_;
// Number of connecting sockets across all groups.
int connecting_socket_count_;
// Number of connected sockets we handed out across all groups.
int handed_out_socket_count_;
// The maximum total number of sockets. See ReachedMaxSocketsLimit.
const int max_sockets_;
// The maximum number of sockets kept per group.
const int max_sockets_per_group_;
// Until the maximum number of sockets limit is reached, a group can only
// have pending requests if it exceeds the "max sockets per group" limit.
//
// This means when a socket is released, the only pending requests that can
// be started next belong to the same group.
//
// However once the |max_sockets_| limit is reached, this stops being true:
// groups can now have pending requests without having first reached the
// |max_sockets_per_group_| limit. So choosing the next request involves
// selecting the highest priority request across *all* groups.
//
// Since reaching the maximum number of sockets is an edge case, we make note
// of when it happens, and thus avoid doing the slower "scan all groups"
// in the common case.
bool may_have_stalled_group_;
const scoped_ptr<ConnectJobFactory> connect_job_factory_;
// Controls whether or not we use late binding of sockets.
static bool g_late_binding;
DISALLOW_COPY_AND_ASSIGN(ClientSocketPoolBase);
};
} // namespace net
#endif // NET_SOCKET_CLIENT_SOCKET_POOL_BASE_H_
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