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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_LOCAL_DATA_PIPE_H_
6 #define MOJO_SYSTEM_LOCAL_DATA_PIPE_H_
7 
8 #include "base/basictypes.h"
9 #include "base/memory/aligned_memory.h"
10 #include "base/memory/ref_counted.h"
11 #include "base/memory/scoped_ptr.h"
12 #include "mojo/system/data_pipe.h"
13 #include "mojo/system/system_impl_export.h"
14 
15 namespace mojo {
16 namespace system {
17 
18 // |LocalDataPipe| is a subclass that "implements" |DataPipe| for data pipes
19 // whose producer and consumer are both local. This class is thread-safe (with
20 // protection provided by |DataPipe|'s |lock_|.
21 class MOJO_SYSTEM_IMPL_EXPORT LocalDataPipe : public DataPipe {
22  public:
23   LocalDataPipe();
24 
25   MojoResult Init(const MojoCreateDataPipeOptions* options);
26 
27  private:
28   friend class base::RefCountedThreadSafe<LocalDataPipe>;
29   virtual ~LocalDataPipe();
30 
31   // |DataPipe| implementation:
32   virtual void ProducerCloseImplNoLock() OVERRIDE;
33   virtual MojoResult ProducerBeginWriteDataImplNoLock(
34       void** buffer,
35       uint32_t* buffer_num_elements,
36       MojoWriteDataFlags flags) OVERRIDE;
37   virtual MojoResult ProducerEndWriteDataImplNoLock(
38       uint32_t num_elements_written) OVERRIDE;
39   virtual MojoWaitFlags ProducerSatisfiedFlagsNoLock() OVERRIDE;
40   virtual MojoWaitFlags ProducerSatisfiableFlagsNoLock() OVERRIDE;
41   virtual void ConsumerCloseImplNoLock() OVERRIDE;
42   virtual MojoResult ConsumerDiscardDataNoLock(uint32_t* num_elements,
43                                                bool all_or_none) OVERRIDE;
44   virtual MojoResult ConsumerQueryDataNoLock(uint32_t* num_elements) OVERRIDE;
45   virtual MojoResult ConsumerBeginReadDataImplNoLock(
46       const void** buffer,
47       uint32_t* buffer_num_elements,
48       MojoReadDataFlags flags) OVERRIDE;
49   virtual MojoResult ConsumerEndReadDataImplNoLock(
50       uint32_t num_elements_read) OVERRIDE;
51   virtual MojoWaitFlags ConsumerSatisfiedFlagsNoLock() OVERRIDE;
52   virtual MojoWaitFlags ConsumerSatisfiableFlagsNoLock() OVERRIDE;
53 
54   void EnsureBufferNoLock();
55 
56   // Get the maximum (single) write/read size right now (in number of elements);
57   // result fits in a |uint32_t|.
58   size_t GetMaxElementsToWriteNoLock();
59   size_t GetMaxElementsToReadNoLock();
60 
61   // The members below are protected by |DataPipe|'s |lock_|:
62   bool producer_open_;
63   bool consumer_open_;
64 
65   scoped_ptr_malloc<char, base::ScopedPtrAlignedFree> buffer_;
66   // Circular buffer.
67   size_t buffer_first_element_index_;
68   size_t buffer_current_num_elements_;
69 
70   uint32_t two_phase_max_elements_written_;
71   uint32_t two_phase_max_elements_read_;
72 
73   DISALLOW_COPY_AND_ASSIGN(LocalDataPipe);
74 };
75 
76 }  // namespace system
77 }  // namespace mojo
78 
79 #endif  // MOJO_SYSTEM_LOCAL_DATA_PIPE_H_
80