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/macros.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
15namespace mojo {
16namespace 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_|.
21class MOJO_SYSTEM_IMPL_EXPORT LocalDataPipe : public DataPipe {
22 public:
23  // |validated_options| should be the output of |DataPipe::ValidateOptions()|.
24  // In particular: |struct_size| is ignored (so |validated_options| must be the
25  // current version of the struct) and |capacity_num_bytes| must be nonzero.
26  explicit LocalDataPipe(const MojoCreateDataPipeOptions& validated_options);
27
28 private:
29  friend class base::RefCountedThreadSafe<LocalDataPipe>;
30  virtual ~LocalDataPipe();
31
32  // |DataPipe| implementation:
33  virtual void ProducerCloseImplNoLock() OVERRIDE;
34  virtual MojoResult ProducerWriteDataImplNoLock(
35      UserPointer<const void> elements,
36      UserPointer<uint32_t> num_bytes,
37      uint32_t max_num_bytes_to_write,
38      uint32_t min_num_bytes_to_write) OVERRIDE;
39  virtual MojoResult ProducerBeginWriteDataImplNoLock(
40      UserPointer<void*> buffer,
41      UserPointer<uint32_t> buffer_num_bytes,
42      uint32_t min_num_bytes_to_write) OVERRIDE;
43  virtual MojoResult ProducerEndWriteDataImplNoLock(
44      uint32_t num_bytes_written) OVERRIDE;
45  virtual HandleSignalsState ProducerGetHandleSignalsStateImplNoLock()
46      const OVERRIDE;
47  virtual void ConsumerCloseImplNoLock() OVERRIDE;
48  virtual MojoResult ConsumerReadDataImplNoLock(
49      UserPointer<void> elements,
50      UserPointer<uint32_t> num_bytes,
51      uint32_t max_num_bytes_to_read,
52      uint32_t min_num_bytes_to_read) OVERRIDE;
53  virtual MojoResult ConsumerDiscardDataImplNoLock(
54      UserPointer<uint32_t> num_bytes,
55      uint32_t max_num_bytes_to_discard,
56      uint32_t min_num_bytes_to_discard) OVERRIDE;
57  virtual MojoResult ConsumerQueryDataImplNoLock(
58      UserPointer<uint32_t> num_bytes) OVERRIDE;
59  virtual MojoResult ConsumerBeginReadDataImplNoLock(
60      UserPointer<const void*> buffer,
61      UserPointer<uint32_t> buffer_num_bytes,
62      uint32_t min_num_bytes_to_read) OVERRIDE;
63  virtual MojoResult ConsumerEndReadDataImplNoLock(
64      uint32_t num_bytes_read) OVERRIDE;
65  virtual HandleSignalsState ConsumerGetHandleSignalsStateImplNoLock()
66      const OVERRIDE;
67
68  void EnsureBufferNoLock();
69  void DestroyBufferNoLock();
70
71  // Get the maximum (single) write/read size right now (in number of elements);
72  // result fits in a |uint32_t|.
73  size_t GetMaxNumBytesToWriteNoLock();
74  size_t GetMaxNumBytesToReadNoLock();
75
76  // Marks the given number of bytes as consumed/discarded. |num_bytes| must be
77  // greater than |current_num_bytes_|.
78  void MarkDataAsConsumedNoLock(size_t num_bytes);
79
80  // The members below are protected by |DataPipe|'s |lock_|:
81  scoped_ptr<char, base::AlignedFreeDeleter> buffer_;
82  // Circular buffer.
83  size_t start_index_;
84  size_t current_num_bytes_;
85
86  DISALLOW_COPY_AND_ASSIGN(LocalDataPipe);
87};
88
89}  // namespace system
90}  // namespace mojo
91
92#endif  // MOJO_SYSTEM_LOCAL_DATA_PIPE_H_
93