mojo/public/cpp/system/data_pipe.h

   1 // Copyright 2014 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_PUBLIC_CPP_SYSTEM_DATA_PIPE_H_
   6 #define MOJO_PUBLIC_CPP_SYSTEM_DATA_PIPE_H_
   7
   8 #include <assert.h>
   9
  10 #include "mojo/public/c/system/data_pipe.h"
  11 #include "mojo/public/cpp/system/handle.h"
  12 #include "mojo/public/cpp/system/macros.h"
  13
  14 namespace mojo {
  15
  16 // DataPipeProducerHandle and DataPipeConsumerHandle ---------------------------
  17
  18 class DataPipeProducerHandle : public Handle {
  19  public:
  20   DataPipeProducerHandle() {}
  21   explicit DataPipeProducerHandle(MojoHandle value) : Handle(value) {}
  22
  23   // Copying and assignment allowed.
  24 };
  25
  26 MOJO_COMPILE_ASSERT(sizeof(DataPipeProducerHandle) == sizeof(Handle),
  27                     bad_size_for_cpp_DataPipeProducerHandle);
  28
  29 typedef ScopedHandleBase<DataPipeProducerHandle> ScopedDataPipeProducerHandle;
  30 MOJO_COMPILE_ASSERT(sizeof(ScopedDataPipeProducerHandle) ==
  31                         sizeof(DataPipeProducerHandle),
  32                     bad_size_for_cpp_ScopedDataPipeProducerHandle);
  33
  34 class DataPipeConsumerHandle : public Handle {
  35  public:
  36   DataPipeConsumerHandle() {}
  37   explicit DataPipeConsumerHandle(MojoHandle value) : Handle(value) {}
  38
  39   // Copying and assignment allowed.
  40 };
  41
  42 MOJO_COMPILE_ASSERT(sizeof(DataPipeConsumerHandle) == sizeof(Handle),
  43                     bad_size_for_cpp_DataPipeConsumerHandle);
  44
  45 typedef ScopedHandleBase<DataPipeConsumerHandle> ScopedDataPipeConsumerHandle;
  46 MOJO_COMPILE_ASSERT(sizeof(ScopedDataPipeConsumerHandle) ==
  47                         sizeof(DataPipeConsumerHandle),
  48                     bad_size_for_cpp_ScopedDataPipeConsumerHandle);
  49
  50 inline MojoResult CreateDataPipe(
  51     const MojoCreateDataPipeOptions* options,
  52     ScopedDataPipeProducerHandle* data_pipe_producer,
  53     ScopedDataPipeConsumerHandle* data_pipe_consumer) {
  54   assert(data_pipe_producer);
  55   assert(data_pipe_consumer);
  56   DataPipeProducerHandle producer_handle;
  57   DataPipeConsumerHandle consumer_handle;
  58   MojoResult rv = MojoCreateDataPipe(options, producer_handle.mutable_value(),
  59                                      consumer_handle.mutable_value());
  60   // Reset even on failure (reduces the chances that a "stale"/incorrect handle
  61   // will be used).
  62   data_pipe_producer->reset(producer_handle);
  63   data_pipe_consumer->reset(consumer_handle);
  64   return rv;
  65 }
  66
  67 inline MojoResult WriteDataRaw(DataPipeProducerHandle data_pipe_producer,
  68                                const void* elements,
  69                                uint32_t* num_bytes,
  70                                MojoWriteDataFlags flags) {
  71   return MojoWriteData(data_pipe_producer.value(), elements, num_bytes, flags);
  72 }
  73
  74 inline MojoResult BeginWriteDataRaw(DataPipeProducerHandle data_pipe_producer,
  75                                     void** buffer,
  76                                     uint32_t* buffer_num_bytes,
  77                                     MojoWriteDataFlags flags) {
  78   return MojoBeginWriteData(data_pipe_producer.value(), buffer,
  79                             buffer_num_bytes, flags);
  80 }
  81
  82 inline MojoResult EndWriteDataRaw(DataPipeProducerHandle data_pipe_producer,
  83                                   uint32_t num_bytes_written) {
  84   return MojoEndWriteData(data_pipe_producer.value(), num_bytes_written);
  85 }
  86
  87 inline MojoResult ReadDataRaw(DataPipeConsumerHandle data_pipe_consumer,
  88                               void* elements,
  89                               uint32_t* num_bytes,
  90                               MojoReadDataFlags flags) {
  91   return MojoReadData(data_pipe_consumer.value(), elements, num_bytes, flags);
  92 }
  93
  94 inline MojoResult BeginReadDataRaw(DataPipeConsumerHandle data_pipe_consumer,
  95                                    const void** buffer,
  96                                    uint32_t* buffer_num_bytes,
  97                                    MojoReadDataFlags flags) {
  98   return MojoBeginReadData(data_pipe_consumer.value(), buffer, buffer_num_bytes,
  99                            flags);
 100 }
 101
 102 inline MojoResult EndReadDataRaw(DataPipeConsumerHandle data_pipe_consumer,
 103                                  uint32_t num_bytes_read) {
 104   return MojoEndReadData(data_pipe_consumer.value(), num_bytes_read);
 105 }
 106
 107 // A wrapper class that automatically creates a data pipe and owns both handles.
 108 // TODO(vtl): Make an even more friendly version? (Maybe templatized for a
 109 // particular type instead of some "element"? Maybe functions that take
 110 // vectors?)
 111 class DataPipe {
 112  public:
 113   DataPipe();
 114   explicit DataPipe(const MojoCreateDataPipeOptions& options);
 115   ~DataPipe();
 116
 117   ScopedDataPipeProducerHandle producer_handle;
 118   ScopedDataPipeConsumerHandle consumer_handle;
 119 };
 120
 121 inline DataPipe::DataPipe() {
 122   MojoResult result MOJO_ALLOW_UNUSED =
 123       CreateDataPipe(NULL, &producer_handle, &consumer_handle);
 124   assert(result == MOJO_RESULT_OK);
 125 }
 126
 127 inline DataPipe::DataPipe(const MojoCreateDataPipeOptions& options) {
 128   MojoResult result MOJO_ALLOW_UNUSED =
 129       CreateDataPipe(&options, &producer_handle, &consumer_handle);
 130   assert(result == MOJO_RESULT_OK);
 131 }
 132
 133 inline DataPipe::~DataPipe() {
 134 }
 135
 136 }  // namespace mojo
 137
 138 #endif  // MOJO_PUBLIC_CPP_SYSTEM_DATA_PIPE_H_