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      1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef NET_SOCKET_CLIENT_SOCKET_HANDLE_H_
      6 #define NET_SOCKET_CLIENT_SOCKET_HANDLE_H_
      7 
      8 #include <string>
      9 
     10 #include "base/logging.h"
     11 #include "base/ref_counted.h"
     12 #include "base/scoped_ptr.h"
     13 #include "base/time.h"
     14 #include "net/base/completion_callback.h"
     15 #include "net/base/load_states.h"
     16 #include "net/base/net_errors.h"
     17 #include "net/base/request_priority.h"
     18 #include "net/socket/client_socket.h"
     19 #include "net/socket/client_socket_pool.h"
     20 
     21 namespace net {
     22 
     23 // A container for a ClientSocket.
     24 //
     25 // The handle's |group_name| uniquely identifies the origin and type of the
     26 // connection.  It is used by the ClientSocketPool to group similar connected
     27 // client socket objects.
     28 //
     29 class ClientSocketHandle {
     30  public:
     31   typedef enum {
     32     UNUSED = 0,   // unused socket that just finished connecting
     33     UNUSED_IDLE,  // unused socket that has been idle for awhile
     34     REUSED_IDLE,  // previously used socket
     35     NUM_TYPES,
     36   } SocketReuseType;
     37 
     38   ClientSocketHandle();
     39   ~ClientSocketHandle();
     40 
     41   // Initializes a ClientSocketHandle object, which involves talking to the
     42   // ClientSocketPool to obtain a connected socket, possibly reusing one.  This
     43   // method returns either OK or ERR_IO_PENDING.  On ERR_IO_PENDING, |priority|
     44   // is used to determine the placement in ClientSocketPool's wait list.
     45   //
     46   // If this method succeeds, then the socket member will be set to an existing
     47   // connected socket if an existing connected socket was available to reuse,
     48   // otherwise it will be set to a new connected socket.  Consumers can then
     49   // call is_reused() to see if the socket was reused.  If not reusing an
     50   // existing socket, ClientSocketPool may need to establish a new
     51   // connection using |socket_params|.
     52   //
     53   // This method returns ERR_IO_PENDING if it cannot complete synchronously, in
     54   // which case the consumer will be notified of completion via |callback|.
     55   //
     56   // Init may be called multiple times.
     57   //
     58   // Profiling information for the request is saved to |load_log| if non-NULL.
     59   //
     60   template <typename SocketParams, typename PoolType>
     61   int Init(const std::string& group_name,
     62            const SocketParams& socket_params,
     63            RequestPriority priority,
     64            CompletionCallback* callback,
     65            PoolType* pool,
     66            LoadLog* load_log);
     67 
     68   // An initialized handle can be reset, which causes it to return to the
     69   // un-initialized state.  This releases the underlying socket, which in the
     70   // case of a socket that still has an established connection, indicates that
     71   // the socket may be kept alive for use by a subsequent ClientSocketHandle.
     72   //
     73   // NOTE: To prevent the socket from being kept alive, be sure to call its
     74   // Disconnect method.  This will result in the ClientSocketPool deleting the
     75   // ClientSocket.
     76   void Reset();
     77 
     78   // Used after Init() is called, but before the ClientSocketPool has
     79   // initialized the ClientSocketHandle.
     80   LoadState GetLoadState() const;
     81 
     82   // Returns true when Init() has completed successfully.
     83   bool is_initialized() const { return socket_ != NULL; }
     84 
     85   // Returns the time tick when Init() was called.
     86   base::TimeTicks init_time() const { return init_time_; }
     87 
     88   // Used by ClientSocketPool to initialize the ClientSocketHandle.
     89   void set_is_reused(bool is_reused) { is_reused_ = is_reused; }
     90   void set_socket(ClientSocket* s) { socket_.reset(s); }
     91   void set_idle_time(base::TimeDelta idle_time) { idle_time_ = idle_time; }
     92 
     93   // These may only be used if is_initialized() is true.
     94   const std::string& group_name() const { return group_name_; }
     95   ClientSocket* socket() { return socket_.get(); }
     96   ClientSocket* release_socket() { return socket_.release(); }
     97   bool is_reused() const { return is_reused_; }
     98   base::TimeDelta idle_time() const { return idle_time_; }
     99   SocketReuseType reuse_type() const {
    100     if (is_reused()) {
    101       return REUSED_IDLE;
    102     } else if (idle_time() == base::TimeDelta()) {
    103       return UNUSED;
    104     } else {
    105       return UNUSED_IDLE;
    106     }
    107   }
    108   bool ShouldResendFailedRequest(int error) const {
    109     // NOTE: we resend a request only if we reused a keep-alive connection.
    110     // This automatically prevents an infinite resend loop because we'll run
    111     // out of the cached keep-alive connections eventually.
    112     if (  // We used a socket that was never idle.
    113         reuse_type() == ClientSocketHandle::UNUSED ||
    114         // We used an unused, idle socket and got a error that wasn't a TCP RST.
    115         (reuse_type() == ClientSocketHandle::UNUSED_IDLE &&
    116          (error != OK && error != ERR_CONNECTION_RESET))) {
    117       return false;
    118     }
    119     return true;
    120   }
    121 
    122  private:
    123   // Called on asynchronous completion of an Init() request.
    124   void OnIOComplete(int result);
    125 
    126   // Called on completion (both asynchronous & synchronous) of an Init()
    127   // request.
    128   void HandleInitCompletion(int result);
    129 
    130   // Resets the state of the ClientSocketHandle.  |cancel| indicates whether or
    131   // not to try to cancel the request with the ClientSocketPool.
    132   void ResetInternal(bool cancel);
    133 
    134   scoped_refptr<ClientSocketPool> pool_;
    135   scoped_ptr<ClientSocket> socket_;
    136   std::string group_name_;
    137   bool is_reused_;
    138   CompletionCallbackImpl<ClientSocketHandle> callback_;
    139   CompletionCallback* user_callback_;
    140   base::TimeDelta idle_time_;
    141   base::TimeTicks init_time_;
    142 
    143   DISALLOW_COPY_AND_ASSIGN(ClientSocketHandle);
    144 };
    145 
    146 // Template function implementation:
    147 template <typename SocketParams, typename PoolType>
    148 int ClientSocketHandle::Init(const std::string& group_name,
    149                              const SocketParams& socket_params,
    150                              RequestPriority priority,
    151                              CompletionCallback* callback,
    152                              PoolType* pool,
    153                              LoadLog* load_log) {
    154   CHECK(!group_name.empty());
    155   // Note that this will result in a link error if the SocketParams has not been
    156   // registered for the PoolType via REGISTER_SOCKET_PARAMS_FOR_POOL (defined in
    157   // client_socket_pool.h).
    158   CheckIsValidSocketParamsForPool<PoolType, SocketParams>();
    159   ResetInternal(true);
    160   pool_ = pool;
    161   group_name_ = group_name;
    162   init_time_ = base::TimeTicks::Now();
    163   int rv = pool_->RequestSocket(
    164       group_name, &socket_params, priority, this, &callback_, load_log);
    165   if (rv == ERR_IO_PENDING) {
    166     user_callback_ = callback;
    167   } else {
    168     HandleInitCompletion(rv);
    169   }
    170   return rv;
    171 }
    172 
    173 }  // namespace net
    174 
    175 #endif  // NET_SOCKET_CLIENT_SOCKET_HANDLE_H_
    176