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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_EDK_SYSTEM_AWAKABLE_LIST_H_
      6 #define MOJO_EDK_SYSTEM_AWAKABLE_LIST_H_
      7 
      8 #include <stddef.h>
      9 #include <stdint.h>
     10 
     11 #include <vector>
     12 
     13 #include "base/macros.h"
     14 #include "mojo/edk/system/system_impl_export.h"
     15 #include "mojo/edk/system/watcher.h"
     16 #include "mojo/edk/system/watcher_set.h"
     17 #include "mojo/public/c/system/types.h"
     18 
     19 namespace mojo {
     20 namespace edk {
     21 
     22 class Awakable;
     23 struct HandleSignalsState;
     24 
     25 // |AwakableList| tracks all the |Waiter|s that are waiting on a given
     26 // handle/|Dispatcher|. There should be a |AwakableList| for each handle that
     27 // can be waited on (in any way). In the simple case, the |AwakableList| is
     28 // owned by the |Dispatcher|, whereas in more complex cases it is owned by the
     29 // secondary object (see simple_dispatcher.* and the explanatory comment in
     30 // core.cc). This class is thread-unsafe (all concurrent access must be
     31 // protected by some lock).
     32 class MOJO_SYSTEM_IMPL_EXPORT AwakableList {
     33  public:
     34   AwakableList();
     35   ~AwakableList();
     36 
     37   void AwakeForStateChange(const HandleSignalsState& state);
     38   void CancelAll();
     39   void Add(Awakable* awakable, MojoHandleSignals signals, uintptr_t context);
     40   void Remove(Awakable* awakable);
     41 
     42   // Add and remove Watchers to this AwakableList.
     43   MojoResult AddWatcher(MojoHandleSignals signals,
     44                         const Watcher::WatchCallback& callback,
     45                         uintptr_t context,
     46                         const HandleSignalsState& current_state);
     47   MojoResult RemoveWatcher(uintptr_t context);
     48 
     49  private:
     50   struct AwakeInfo {
     51     AwakeInfo(Awakable* awakable, MojoHandleSignals signals, uintptr_t context)
     52         : awakable(awakable), signals(signals), context(context) {}
     53 
     54     Awakable* awakable;
     55     MojoHandleSignals signals;
     56     uintptr_t context;
     57   };
     58   using AwakeInfoList = std::vector<AwakeInfo>;
     59 
     60   AwakeInfoList awakables_;
     61 
     62   // TODO: Remove AwakableList and instead use WatcherSet directly in
     63   // dispatchers.
     64   WatcherSet watchers_;
     65 
     66   DISALLOW_COPY_AND_ASSIGN(AwakableList);
     67 };
     68 
     69 }  // namespace edk
     70 }  // namespace mojo
     71 
     72 #endif  // MOJO_EDK_SYSTEM_AWAKABLE_LIST_H_
     73