mojo/system/local_data_pipe.h

   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
  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   // |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_