Revert "Revert "Revert "Add connected socket function to ClientSocketPool and ClientSocketHandle."""

net/base/client_socket_pool.cc

 // 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.
 
 #include "net/base/client_socket_pool.h"
 
-#include "base/compiler_specific.h"
-#include "base/field_trial.h"
 #include "base/message_loop.h"
-#include "base/time.h"
-#include "base/stl_util-inl.h"
-#include "net/base/client_socket_factory.h"
+#include "net/base/client_socket.h"
 #include "net/base/client_socket_handle.h"
-#include "net/base/dns_resolution_observer.h"
 #include "net/base/net_errors.h"
-#include "net/base/tcp_client_socket.h"
 
 using base::TimeDelta;
 
 namespace {
 
 // The timeout value, in seconds, used to clean up idle sockets that can't be
 // reused.
 //
 // Note: It's important to close idle sockets that have received data as soon
 // as possible because the received data may cause BSOD on Windows XP under
 // some conditions.  See http://crbug.com/4606.
 const int kCleanupInterval = 10;  // DO NOT INCREASE THIS TIMEOUT.
 
 // The maximum duration, in seconds, to keep idle persistent sockets alive.
 const int kIdleTimeout = 300;  // 5 minutes.
 
 }  // namespace
 
 namespace net {
 
-ClientSocketPool::ConnectingSocket::ConnectingSocket(
-    const std::string& group_name,
-    const ClientSocketHandle* handle,
-    ClientSocketFactory* client_socket_factory,
-    ClientSocketPool* pool)
-    : group_name_(group_name),
-      handle_(handle),
-      client_socket_factory_(client_socket_factory),
-      ALLOW_THIS_IN_INITIALIZER_LIST(
-          callback_(this,
-                    &ClientSocketPool::ConnectingSocket::OnIOComplete)),
-      pool_(pool) {}
-
-ClientSocketPool::ConnectingSocket::~ConnectingSocket() {}
-
-int ClientSocketPool::ConnectingSocket::Connect(
-    const std::string& host,
-    int port,
-    CompletionCallback* callback) {
-  DidStartDnsResolution(host, this);
-  int rv = resolver_.Resolve(host, port, &addresses_, &callback_);
-  if (rv == OK) {
-    // TODO(willchan): This code is broken.  It should be fixed, but the code
-    // path is impossible in the current implementation since the host resolver
-    // always dumps the request to a worker pool, so it cannot complete
-    // synchronously.
-    connect_start_time_ = base::Time::Now();
-    rv = socket_->Connect(&callback_);
-  }
-  return rv;
-}
-
-ClientSocket* ClientSocketPool::ConnectingSocket::ReleaseSocket() {
-  return socket_.release();
-}
-
-void ClientSocketPool::ConnectingSocket::OnIOComplete(int result) {
-  DCHECK_NE(result, ERR_IO_PENDING);
-
-  GroupMap::iterator group_it = pool_->group_map_.find(group_name_);
-  if (group_it == pool_->group_map_.end()) {
-    // The request corresponding to this ConnectingSocket has been canceled.
-    // Stop bothering with it.
-    delete this;
-    return;
-  }
-
-  Group& group = group_it->second;
-
-  RequestMap* request_map = &group.connecting_requests;
-  RequestMap::iterator it = request_map->find(handle_);
-  if (it == request_map->end()) {
-    // The request corresponding to this ConnectingSocket has been canceled.
-    // Stop bothering with it.
-    group.active_socket_count--;
-
-    // Delete group if no longer needed.
-    if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
-      DCHECK(group.pending_requests.empty());
-      DCHECK(group.connecting_requests.empty());
-      pool_->group_map_.erase(group_it);
-    }
-    delete this;
-    return;
-  }
-
-  if (result == OK) {
-    if (it->second.load_state == LOAD_STATE_RESOLVING_HOST) {
-      it->second.load_state = LOAD_STATE_CONNECTING;
-      socket_.reset(client_socket_factory_->CreateTCPClientSocket(addresses_));
-      connect_start_time_ = base::Time::Now();
-      result = socket_->Connect(&callback_);
-      if (result == ERR_IO_PENDING)
-        return;
-    } else {
-      DCHECK(connect_start_time_ != base::Time());
-      base::TimeDelta connect_duration =
-          base::Time::Now() - connect_start_time_;
-
-      UMA_HISTOGRAM_CLIPPED_TIMES(
-          FieldTrial::MakeName(
-              "Net.TCP_Connection_Latency", "DnsImpact").data(),
-          connect_duration,
-          base::TimeDelta::FromMilliseconds(1),
-          base::TimeDelta::FromMinutes(10),
-          100);
-    }
-  }
-
-  // Now, we either succeeded at Connect()'ing, or we failed at host resolution
-  // or Connect()'ing.  Either way, we'll run the callback to alert the client.
-
-  Request request = it->second;
-  request_map->erase(it);
-
-  if (result == OK) {
-    request.handle->set_socket(socket_.release());
-    request.handle->set_is_reused(false);
-  } else {
-    group.active_socket_count--;
-
-    // Delete group if no longer needed.
-    if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
-      DCHECK(group.pending_requests.empty());
-      DCHECK(group.connecting_requests.empty());
-      pool_->group_map_.erase(group_it);
-    }
-  }
-
-  request.callback->Run(result);
-  delete this;
-}
-
-ClientSocketPool::ClientSocketPool(int max_sockets_per_group,
-                                   ClientSocketFactory* client_socket_factory)
-    : client_socket_factory_(client_socket_factory),
-      idle_socket_count_(0),
+ClientSocketPool::ClientSocketPool(int max_sockets_per_group)
+    : idle_socket_count_(0),
       max_sockets_per_group_(max_sockets_per_group) {
 }
 
 ClientSocketPool::~ClientSocketPool() {
   // Clean up any idle sockets.  Assert that we have no remaining active
   // sockets or pending requests.  They should have all been cleaned up prior
   // to the manager being destroyed.
   CloseIdleSockets();
   DCHECK(group_map_.empty());
 }
 
 // InsertRequestIntoQueue inserts the request into the queue based on
 // priority.  Highest priorities are closest to the front.  Older requests are
 // prioritized over requests of equal priority.
 //
 // static
 void ClientSocketPool::InsertRequestIntoQueue(const Request& r,
                                               RequestQueue* pending_requests) {
   RequestQueue::iterator it = pending_requests->begin();
   while (it != pending_requests->end() && r.priority <= it->priority)
     ++it;
   pending_requests->insert(it, r);
 }
 
-int ClientSocketPool::RequestSocket(const std::string& group_name,
-                                    const std::string& host,
-                                    int port,
+int ClientSocketPool::RequestSocket(ClientSocketHandle* handle,
                                     int priority,
-                                    ClientSocketHandle* handle,
                                     CompletionCallback* callback) {
-  DCHECK(!host.empty());
-  DCHECK_GE(priority, 0);
-  Group& group = group_map_[group_name];
+  Group& group = group_map_[handle->group_name_];
 
   // Can we make another active socket now?
   if (group.active_socket_count == max_sockets_per_group_) {
     Request r;
     r.handle = handle;
     DCHECK(callback);
     r.callback = callback;
     r.priority = priority;
-    r.host = host;
-    r.port = port;
-    r.load_state = LOAD_STATE_IDLE;
     InsertRequestIntoQueue(r, &group.pending_requests);
     return ERR_IO_PENDING;
   }
 
   // OK, we are going to activate one.
   group.active_socket_count++;
 
+  // Use idle sockets in LIFO order because they're more likely to be
+  // still reusable.
   while (!group.idle_sockets.empty()) {
     IdleSocket idle_socket = group.idle_sockets.back();
     group.idle_sockets.pop_back();
     DecrementIdleCount();
-    if (idle_socket.socket->IsConnectedAndIdle()) {
+    if ((*idle_socket.ptr)->IsConnectedAndIdle()) {
       // We found one we can reuse!
-      handle->set_socket(idle_socket.socket);
-      handle->set_is_reused(true);
+      handle->socket_ = idle_socket.ptr;
       return OK;
     }
-    delete idle_socket.socket;
+    delete idle_socket.ptr;
   }
 
-  // We couldn't find a socket to reuse, so allocate and connect a new one.
-  scoped_ptr<ConnectingSocket> connecting_socket(
-      new ConnectingSocket(group_name, handle, client_socket_factory_, this));
-  int rv = connecting_socket->Connect(host, port, callback);
-  if (rv == OK) {
-    handle->set_socket(connecting_socket->ReleaseSocket());
-    handle->set_is_reused(false);
-  } else if (rv == ERR_IO_PENDING) {
-    // The ConnectingSocket will delete itself.
-    connecting_socket.release();
-    Request r;
-    r.handle = handle;
-    DCHECK(callback);
-    r.callback = callback;
-    r.priority = priority;
-    r.host = host;
-    r.port = port;
-    r.load_state = LOAD_STATE_RESOLVING_HOST;
-    group_map_[group_name].connecting_requests[handle] = r;
-  } else {
-    group.active_socket_count--;
-
-    // Delete group if no longer needed.
-    if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
-      DCHECK(group.pending_requests.empty());
-      DCHECK(group.connecting_requests.empty());
-      group_map_.erase(group_name);
-    }
-  }
-
-  return rv;
+  handle->socket_ = new ClientSocketPtr();
+  return OK;
 }
 
-void ClientSocketPool::CancelRequest(const std::string& group_name,
-                                     const ClientSocketHandle* handle) {
-  DCHECK(ContainsKey(group_map_, group_name));
+void ClientSocketPool::CancelRequest(ClientSocketHandle* handle) {
+  Group& group = group_map_[handle->group_name_];
 
-  Group& group = group_map_[group_name];
+  // In order for us to be canceling a pending request, we must have active
+  // sockets equaling the limit.  NOTE: The correctness of the code doesn't
+  // require this assertion.
+  DCHECK(group.active_socket_count == max_sockets_per_group_);
 
   // Search pending_requests for matching handle.
-  RequestQueue::iterator it = group.pending_requests.begin();
+  std::deque<Request>::iterator it = group.pending_requests.begin();
   for (; it != group.pending_requests.end(); ++it) {
     if (it->handle == handle) {
       group.pending_requests.erase(it);
-      return;
-    }
-  }
-
-  // It's invalid to cancel a non-existent request.
-  DCHECK(ContainsKey(group.connecting_requests, handle));
-
-  RequestMap::iterator map_it = group.connecting_requests.find(handle);
-  if (map_it != group.connecting_requests.end()) {
-    group.connecting_requests.erase(map_it);
-    group.active_socket_count--;
-
-    // Delete group if no longer needed.
-    if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
-      DCHECK(group.pending_requests.empty());
-      DCHECK(group.connecting_requests.empty());
-      group_map_.erase(group_name);
+      break;
     }
   }
 }
 
-void ClientSocketPool::ReleaseSocket(const std::string& group_name,
-                                     ClientSocket* socket) {
+void ClientSocketPool::ReleaseSocket(ClientSocketHandle* handle) {
   // Run this asynchronously to allow the caller to finish before we let
   // another to begin doing work.  This also avoids nasty recursion issues.
   // NOTE: We cannot refer to the handle argument after this method returns.
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      this, &ClientSocketPool::DoReleaseSocket, group_name, socket));
+      this, &ClientSocketPool::DoReleaseSocket, handle->group_name_,
+      handle->socket_));
 }
 
 void ClientSocketPool::CloseIdleSockets() {
   CleanupIdleSockets(true);
 }
 
 int ClientSocketPool::IdleSocketCountInGroup(
     const std::string& group_name) const {
   GroupMap::const_iterator i = group_map_.find(group_name);
   DCHECK(i != group_map_.end());
 
   return i->second.idle_sockets.size();
 }
 
-LoadState ClientSocketPool::GetLoadState(
-    const std::string& group_name,
-    const ClientSocketHandle* handle) const {
-  DCHECK(ContainsKey(group_map_, group_name)) << group_name;
-
-  // Can't use operator[] since it is non-const.
-  const Group& group = group_map_.find(group_name)->second;
-
-  // Search connecting_requests for matching handle.
-  RequestMap::const_iterator map_it = group.connecting_requests.find(handle);
-  if (map_it != group.connecting_requests.end()) {
-    const LoadState load_state = map_it->second.load_state;
-    DCHECK(load_state == LOAD_STATE_RESOLVING_HOST ||
-           load_state == LOAD_STATE_CONNECTING);
-    return load_state;
-  }
-
-  // Search pending_requests for matching handle.
-  RequestQueue::const_iterator it = group.pending_requests.begin();
-  for (; it != group.pending_requests.end(); ++it) {
-    if (it->handle == handle) {
-      DCHECK_EQ(LOAD_STATE_IDLE, it->load_state);
-      // TODO(wtc): Add a state for being on the wait list.
-      // See http://www.crbug.com/5077.
-      return LOAD_STATE_IDLE;
-    }
-  }
-
-  NOTREACHED();
-  return LOAD_STATE_IDLE;
-}
-
 bool ClientSocketPool::IdleSocket::ShouldCleanup(base::TimeTicks now) const {
   bool timed_out = (now - start_time) >=
       base::TimeDelta::FromSeconds(kIdleTimeout);
-  return timed_out || !socket->IsConnectedAndIdle();
+  return timed_out || !(*ptr)->IsConnectedAndIdle();
 }
 
 void ClientSocketPool::CleanupIdleSockets(bool force) {
   if (idle_socket_count_ == 0)
     return;
 
   // Current time value. Retrieving it once at the function start rather than
   // inside the inner loop, since it shouldn't change by any meaningful amount.
   base::TimeTicks now = base::TimeTicks::Now();
 
   GroupMap::iterator i = group_map_.begin();
   while (i != group_map_.end()) {
     Group& group = i->second;
 
     std::deque<IdleSocket>::iterator j = group.idle_sockets.begin();
     while (j != group.idle_sockets.end()) {
       if (force || j->ShouldCleanup(now)) {
-        delete j->socket;
+        delete j->ptr;
         j = group.idle_sockets.erase(j);
         DecrementIdleCount();
       } else {
         ++j;
       }
     }
 
     // Delete group if no longer needed.
     if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
       DCHECK(group.pending_requests.empty());
-      DCHECK(group.connecting_requests.empty());
       group_map_.erase(i++);
     } else {
       ++i;
     }
   }
 }
 
 void ClientSocketPool::IncrementIdleCount() {
   if (++idle_socket_count_ == 1)
     timer_.Start(TimeDelta::FromSeconds(kCleanupInterval), this,
                  &ClientSocketPool::OnCleanupTimerFired);
 }
 
 void ClientSocketPool::DecrementIdleCount() {
   if (--idle_socket_count_ == 0)
     timer_.Stop();
 }
 
 void ClientSocketPool::DoReleaseSocket(const std::string& group_name,
-                                       ClientSocket* socket) {
+                                       ClientSocketPtr* ptr) {
   GroupMap::iterator i = group_map_.find(group_name);
   DCHECK(i != group_map_.end());
 
   Group& group = i->second;
 
-  DCHECK_GT(group.active_socket_count, 0);
+  DCHECK(group.active_socket_count > 0);
   group.active_socket_count--;
 
-  const bool can_reuse = socket->IsConnectedAndIdle();
+  bool can_reuse = ptr->get() && (*ptr)->IsConnectedAndIdle();
   if (can_reuse) {
     IdleSocket idle_socket;
-    idle_socket.socket = socket;
+    idle_socket.ptr = ptr;
     idle_socket.start_time = base::TimeTicks::Now();
 
     group.idle_sockets.push_back(idle_socket);
     IncrementIdleCount();
   } else {
-    delete socket;
+    delete ptr;
   }
 
   // Process one pending request.
   if (!group.pending_requests.empty()) {
     Request r = group.pending_requests.front();
     group.pending_requests.pop_front();
-
-    int rv = RequestSocket(
-        group_name, r.host, r.port, r.priority, r.handle, r.callback);
-    if (rv != ERR_IO_PENDING)
-      r.callback->Run(rv);
+    int rv = RequestSocket(r.handle, r.priority, NULL);
+    DCHECK(rv == OK);
+    r.callback->Run(rv);
     return;
   }
 
   // Delete group if no longer needed.
   if (group.active_socket_count == 0 && group.idle_sockets.empty()) {
     DCHECK(group.pending_requests.empty());
-    DCHECK(group.connecting_requests.empty());
     group_map_.erase(i);
   }
 }
 
 }  // namespace net