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      1 // Copyright 2013 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 MOJO_COMMON_MESSAGE_PUMP_MOJO_H_
      6 #define MOJO_COMMON_MESSAGE_PUMP_MOJO_H_
      7 
      8 #include <map>
      9 
     10 #include "base/memory/scoped_ptr.h"
     11 #include "base/message_loop/message_pump.h"
     12 #include "base/synchronization/lock.h"
     13 #include "base/time/time.h"
     14 #include "mojo/common/mojo_common_export.h"
     15 #include "mojo/public/cpp/system/core.h"
     16 
     17 namespace mojo {
     18 namespace common {
     19 
     20 class MessagePumpMojoHandler;
     21 
     22 // Mojo implementation of MessagePump.
     23 class MOJO_COMMON_EXPORT MessagePumpMojo : public base::MessagePump {
     24  public:
     25   MessagePumpMojo();
     26   virtual ~MessagePumpMojo();
     27 
     28   // Static factory function (for using with |base::Thread::Options|, wrapped
     29   // using |base::Bind()|).
     30   static scoped_ptr<base::MessagePump> Create();
     31 
     32   // Registers a MessagePumpMojoHandler for the specified handle. Only one
     33   // handler can be registered for a specified handle.
     34   void AddHandler(MessagePumpMojoHandler* handler,
     35                   const Handle& handle,
     36                   MojoHandleSignals wait_signals,
     37                   base::TimeTicks deadline);
     38 
     39   void RemoveHandler(const Handle& handle);
     40 
     41   // MessagePump:
     42   virtual void Run(Delegate* delegate) OVERRIDE;
     43   virtual void Quit() OVERRIDE;
     44   virtual void ScheduleWork() OVERRIDE;
     45   virtual void ScheduleDelayedWork(
     46       const base::TimeTicks& delayed_work_time) OVERRIDE;
     47 
     48  private:
     49   struct RunState;
     50   struct WaitState;
     51 
     52   // Contains the data needed to track a request to AddHandler().
     53   struct Handler {
     54     Handler() : handler(NULL), wait_signals(MOJO_HANDLE_SIGNAL_NONE), id(0) {}
     55 
     56     MessagePumpMojoHandler* handler;
     57     MojoHandleSignals wait_signals;
     58     base::TimeTicks deadline;
     59     // See description of |MessagePumpMojo::next_handler_id_| for details.
     60     int id;
     61   };
     62 
     63   typedef std::map<Handle, Handler> HandleToHandler;
     64 
     65   // Implementation of Run().
     66   void DoRunLoop(RunState* run_state, Delegate* delegate);
     67 
     68   // Services the set of handles ready. If |block| is true this waits for a
     69   // handle to become ready, otherwise this does not block.
     70   void DoInternalWork(const RunState& run_state, bool block);
     71 
     72   // Removes the first invalid handle. This is called if MojoWaitMany finds an
     73   // invalid handle.
     74   void RemoveFirstInvalidHandle(const WaitState& wait_state);
     75 
     76   void SignalControlPipe(const RunState& run_state);
     77 
     78   WaitState GetWaitState(const RunState& run_state) const;
     79 
     80   // Returns the deadline for the call to MojoWaitMany().
     81   MojoDeadline GetDeadlineForWait(const RunState& run_state) const;
     82 
     83   // If non-NULL we're running (inside Run()). Member is reference to value on
     84   // stack.
     85   RunState* run_state_;
     86 
     87   // Lock for accessing |run_state_|. In general the only method that we have to
     88   // worry about is ScheduleWork(). All other methods are invoked on the same
     89   // thread.
     90   base::Lock run_state_lock_;
     91 
     92   HandleToHandler handlers_;
     93 
     94   // An ever increasing value assigned to each Handler::id. Used to detect
     95   // uniqueness while notifying. That is, while notifying expired timers we copy
     96   // |handlers_| and only notify handlers whose id match. If the id does not
     97   // match it means the handler was removed then added so that we shouldn't
     98   // notify it.
     99   int next_handler_id_;
    100 
    101   DISALLOW_COPY_AND_ASSIGN(MessagePumpMojo);
    102 };
    103 
    104 }  // namespace common
    105 }  // namespace mojo
    106 
    107 #endif  // MOJO_COMMON_MESSAGE_PUMP_MOJO_H_
    108