mojo/common/data_pipe_utils.cc

   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 #include "mojo/common/data_pipe_utils.h"
   6
   7 #include <stdio.h>
   8
   9 #include "base/files/file_path.h"
  10 #include "base/files/file_util.h"
  11 #include "base/files/scoped_file.h"
  12 #include "base/message_loop/message_loop.h"
  13 #include "base/task_runner_util.h"
  14
  15 namespace mojo {
  16 namespace common {
  17 namespace {
  18
  19 bool BlockingCopyHelper(ScopedDataPipeConsumerHandle source,
  20     const base::Callback<size_t(const void*, uint32_t)>& write_bytes) {
  21   for (;;) {
  22     const void* buffer;
  23     uint32_t num_bytes;
  24     MojoResult result = BeginReadDataRaw(
  25         source.get(), &buffer, &num_bytes, MOJO_READ_DATA_FLAG_NONE);
  26     if (result == MOJO_RESULT_OK) {
  27       size_t bytes_written = write_bytes.Run(buffer, num_bytes);
  28       result = EndReadDataRaw(source.get(), num_bytes);
  29       if (bytes_written < num_bytes || result != MOJO_RESULT_OK)
  30         return false;
  31     } else if (result == MOJO_RESULT_SHOULD_WAIT) {
  32       result = Wait(source.get(),
  33                     MOJO_HANDLE_SIGNAL_READABLE,
  34                     MOJO_DEADLINE_INDEFINITE);
  35       if (result != MOJO_RESULT_OK) {
  36         // If the producer handle was closed, then treat as EOF.
  37         return result == MOJO_RESULT_FAILED_PRECONDITION;
  38       }
  39     } else if (result == MOJO_RESULT_FAILED_PRECONDITION) {
  40       // If the producer handle was closed, then treat as EOF.
  41       return true;
  42     } else {
  43       // Some other error occurred.
  44       break;
  45     }
  46   }
  47
  48   return false;
  49 }
  50
  51 size_t CopyToStringHelper(
  52     std::string* result, const void* buffer, uint32_t num_bytes) {
  53   result->append(static_cast<const char*>(buffer), num_bytes);
  54   return num_bytes;
  55 }
  56
  57 size_t CopyToFileHelper(FILE* fp, const void* buffer, uint32_t num_bytes) {
  58   return fwrite(buffer, 1, num_bytes, fp);
  59 }
  60
  61 } // namespace
  62
  63
  64 // TODO(hansmuller): Add a max_size parameter.
  65 bool BlockingCopyToString(ScopedDataPipeConsumerHandle source,
  66                           std::string* result) {
  67   CHECK(result);
  68   result->clear();
  69   return BlockingCopyHelper(
  70       source.Pass(), base::Bind(&CopyToStringHelper, result));
  71 }
  72
  73 bool BlockingCopyToFile(ScopedDataPipeConsumerHandle source,
  74                         const base::FilePath& destination) {
  75   base::ScopedFILE fp(base::OpenFile(destination, "wb"));
  76   if (!fp)
  77     return false;
  78   return BlockingCopyHelper(
  79       source.Pass(), base::Bind(&CopyToFileHelper, fp.get()));
  80 }
  81
  82 void CopyToFile(ScopedDataPipeConsumerHandle source,
  83                 const base::FilePath& destination,
  84                 base::TaskRunner* task_runner,
  85                 const base::Callback<void(bool)>& callback) {
  86   base::PostTaskAndReplyWithResult(
  87       task_runner,
  88       FROM_HERE,
  89       base::Bind(&BlockingCopyToFile, base::Passed(&source), destination),
  90       callback);
  91 }
  92
  93 }  // namespace common
  94 }  // namespace mojo