native_client_sdk/src/libraries/nacl_io/event_emitter.h

   1 // Copyright (c) 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 #ifndef LIBRARIES_NACL_IO_EVENT_EMITTER_H_
   5 #define LIBRARIES_NACL_IO_EVENT_EMITTER_H_
   6
   7 #include <stdint.h>
   8
   9 #include <map>
  10 #include <set>
  11
  12 #include "nacl_io/error.h"
  13
  14 #include "sdk_util/auto_lock.h"
  15 #include "sdk_util/macros.h"
  16 #include "sdk_util/ref_object.h"
  17 #include "sdk_util/scoped_ref.h"
  18 #include "sdk_util/simple_lock.h"
  19
  20 namespace nacl_io {
  21
  22 class EventEmitter;
  23 class EventListener;
  24
  25 typedef sdk_util::ScopedRef<EventEmitter> ScopedEventEmitter;
  26 typedef std::map<EventListener*, uint32_t> EventListenerMap_t;
  27
  28 bool operator<(const ScopedEventEmitter& src_a,
  29                const ScopedEventEmitter& src_b);
  30
  31 // EventEmitter
  32 //
  33 // The EventEmitter class provides notification of events to EventListeners
  34 // by registering EventInfo objects and signaling the EventListener
  35 // whenever thier state is changed.
  36 //
  37 // See "Kernel Events" in event_listener.h for additional information.
  38
  39 class EventEmitter : public sdk_util::RefObject {
  40  public:
  41   EventEmitter();
  42
  43   // This returns a snapshot, to ensure the status doesn't change from
  44   // fetch to use, hold the lock and call GetEventStatus_Locked.
  45   uint32_t GetEventStatus() {
  46     AUTO_LOCK(emitter_lock_);
  47     return GetEventStatus_Locked();
  48   }
  49
  50   uint32_t GetEventStatus_Locked() { return event_status_; }
  51
  52   sdk_util::SimpleLock& GetLock() { return emitter_lock_; }
  53
  54   // Updates the specified bits in the event status, and signals any
  55   // listeners waiting on those bits.
  56   void RaiseEvents_Locked(uint32_t events);
  57
  58   // Clears the specified bits in the event status.
  59   void ClearEvents_Locked(uint32_t events);
  60
  61   // Register or unregister an EventInfo.  The lock of the EventListener
  62   // associated with this EventInfo must be held prior to calling these
  63   // functions.  These functions are private to ensure they are called by the
  64   // EventListener.
  65   void RegisterListener(EventListener* listener, uint32_t events);
  66   void UnregisterListener(EventListener* listener);
  67   void RegisterListener_Locked(EventListener* listener, uint32_t events);
  68   void UnregisterListener_Locked(EventListener* listener);
  69
  70  private:
  71   uint32_t event_status_;
  72   sdk_util::SimpleLock emitter_lock_;
  73   EventListenerMap_t listeners_;
  74   DISALLOW_COPY_AND_ASSIGN(EventEmitter);
  75 };
  76
  77 }  // namespace nacl_io
  78
  79 #endif  // LIBRARIES_NACL_IO_EVENT_EMITTER_H_