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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_SYSTEM_SIMPLE_DISPATCHER_H_
6 #define MOJO_SYSTEM_SIMPLE_DISPATCHER_H_
7 
8 #include <list>
9 
10 #include "base/basictypes.h"
11 #include "mojo/system/dispatcher.h"
12 #include "mojo/system/system_impl_export.h"
13 #include "mojo/system/waiter_list.h"
14 
15 namespace mojo {
16 namespace system {
17 
18 // A base class for simple dispatchers. "Simple" means that there's a one-to-one
19 // correspondence between handles and dispatchers (see the explanatory comment
20 // in core_impl.cc). This class implements the standard waiter-signalling
21 // mechanism in that case.
22 class MOJO_SYSTEM_IMPL_EXPORT SimpleDispatcher : public Dispatcher {
23  protected:
24   SimpleDispatcher();
25 
26   friend class base::RefCountedThreadSafe<SimpleDispatcher>;
27   virtual ~SimpleDispatcher();
28 
29   // To be called by subclasses when the state changes (so
30   // |SatisfiedFlagsNoLock()| and |SatisfiableFlagsNoLock()| should be checked
31   // again). Must be called under lock.
32   void StateChangedNoLock();
33 
34   // These should return the wait flags that are satisfied by the object's
35   // current state and those that may eventually be satisfied by this object's
36   // state, respectively. They should be overridden by subclasses to reflect
37   // their notion of state. They are never called after the dispatcher has been
38   // closed. They are called under |lock_|.
39   virtual MojoWaitFlags SatisfiedFlagsNoLock() const = 0;
40   virtual MojoWaitFlags SatisfiableFlagsNoLock() const = 0;
41 
42   // |Dispatcher| implementation/overrides:
43   virtual void CancelAllWaitersNoLock() OVERRIDE;
44   virtual MojoResult AddWaiterImplNoLock(Waiter* waiter,
45                                          MojoWaitFlags flags,
46                                          MojoResult wake_result) OVERRIDE;
47   virtual void RemoveWaiterImplNoLock(Waiter* waiter) OVERRIDE;
48 
49  private:
50   // Protected by |lock()|:
51   WaiterList waiter_list_;
52 
53   DISALLOW_COPY_AND_ASSIGN(SimpleDispatcher);
54 };
55 
56 }  // namespace system
57 }  // namespace mojo
58 
59 #endif  // MOJO_SYSTEM_SIMPLE_DISPATCHER_H_
60