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 */ 5 #ifndef LIBRARIES_NACL_IO_EVENT_EMITTER_H_ 6 #define LIBRARIES_NACL_IO_EVENT_EMITTER_H_ 7 8 #include <stdint.h> 9 10 #include <map> 11 #include <set> 12 13 #include "nacl_io/error.h" 14 15 #include "sdk_util/ref_object.h" 16 #include "sdk_util/scoped_ref.h" 17 #include "sdk_util/simple_lock.h" 18 19 20 namespace nacl_io { 21 22 class EventEmitter; 23 class EventListener; 24 25 // A ref counted object (non POD derived from RefObject) for storing the 26 // state of a single signal request. Requests are unique to any 27 // FD/EventListener pair. 28 struct EventInfo : public sdk_util::RefObject { 29 // User provied data to be returned on EventListener::Wait 30 uint64_t user_data; 31 32 // Bitfield of POLL events currently signaled. 33 uint32_t events; 34 35 // Bitfield of POLL events of interest. 36 uint32_t filter; 37 38 // We do not use a ScopedRef to prevent circular references. 39 EventEmitter* emitter; 40 EventListener* listener; 41 uint32_t id; 42 }; 43 44 typedef sdk_util::ScopedRef<EventInfo> ScopedEventInfo; 45 46 // Provide comparison for std::map and std::set 47 bool operator<(const ScopedEventInfo& src_a, const ScopedEventInfo& src_b); 48 49 typedef std::map<int, ScopedEventInfo> EventInfoMap_t; 50 typedef std::set<ScopedEventInfo> EventInfoSet_t; 51 52 // EventEmitter 53 // 54 // The EventEmitter class provides notification of events to EventListeners 55 // by registering EventInfo objects and signaling the EventListener 56 // whenever thier state is changed. 57 // 58 // See "Kernel Events" in event_listener.h for additional information. 59 class EventEmitter : public sdk_util::RefObject { 60 protected: 61 // Called automatically prior to delete to inform the EventListeners that 62 // this EventEmitter is abandoning an associated EventInfo. 63 virtual void Destroy(); 64 65 private: 66 // Register or unregister an EventInfo. The lock of the EventListener 67 // associated with this EventInfo must be held prior to calling these 68 // functions. These functions are private to ensure they are called by the 69 // EventListener. 70 void RegisterEventInfo(const ScopedEventInfo& info); 71 void UnregisterEventInfo(const ScopedEventInfo& info); 72 73 public: 74 // Returns the current state of the emitter as POLL events bitfield. 75 virtual uint32_t GetEventStatus() = 0; 76 77 // Returns the type of the emitter (compatible with st_mode in stat) 78 virtual int GetType() = 0; 79 80 protected: 81 // Called by the thread causing the Event. 82 void RaiseEvent(uint32_t events); 83 84 // Provided to allow one EventEmitter to register the same EventInfo with 85 // a child EventEmitter so that they can both signal the EventListener. 86 // Called after registering locally, but while lock is still held. 87 virtual void ChainRegisterEventInfo(const ScopedEventInfo& event); 88 89 // Called before unregistering locally, but while lock is still held. 90 virtual void ChainUnregisterEventInfo(const ScopedEventInfo& event); 91 92 private: 93 sdk_util::SimpleLock emitter_lock_; 94 EventInfoSet_t events_; 95 friend class EventListener; 96 }; 97 98 typedef sdk_util::ScopedRef<EventEmitter> ScopedEventEmitter; 99 100 } // namespace nacl_io 101 102 103 #endif // LIBRARIES_NACL_IO_EVENT_EMITTER_H_
