Move wm_flow off of views and onto Sky

mojo/common/data_pipe_utils.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/common/data_pipe_utils.h"
 
 #include <stdio.h>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/message_loop/message_loop.h"
 #include "base/task_runner_util.h"
 #include "base/threading/platform_thread.h"
 
 namespace mojo {
 namespace common {
 namespace {
 
 bool BlockingCopyHelper(ScopedDataPipeConsumerHandle source,
     const base::Callback<size_t(const void*, uint32_t)>& write_bytes) {
   for (;;) {
     const void* buffer = nullptr;
     uint32_t num_bytes = 0;
     MojoResult result = BeginReadDataRaw(
         source.get(), &buffer, &num_bytes, MOJO_READ_DATA_FLAG_NONE);
     if (result == MOJO_RESULT_OK) {
       size_t bytes_written = write_bytes.Run(buffer, num_bytes);
+      if (bytes_written < num_bytes) {
+        LOG(ERROR) << "write_bytes callback wrote fewer bytes ("
+                   << bytes_written << ") written than expected (" << num_bytes
+                   << ") in BlockingCopyHelper "
+                   << "(pipe closed? out of disk space?)" << std::endl;
+        return false;
+      }
       result = EndReadDataRaw(source.get(), num_bytes);
-      if (bytes_written < num_bytes || result != MOJO_RESULT_OK)
+      if (result != MOJO_RESULT_OK) {
+        LOG(ERROR) << "EndReadDataRaw error (" << result
+                   << ") in BlockingCopyHelper" << std::endl;
         return false;
+      }
     } else if (result == MOJO_RESULT_SHOULD_WAIT) {
       result = Wait(source.get(),
                     MOJO_HANDLE_SIGNAL_READABLE,
                     MOJO_DEADLINE_INDEFINITE);
       if (result != MOJO_RESULT_OK) {
         // If the producer handle was closed, then treat as EOF.
         return result == MOJO_RESULT_FAILED_PRECONDITION;
       }
     } else if (result == MOJO_RESULT_FAILED_PRECONDITION) {
       // If the producer handle was closed, then treat as EOF.
       return true;
     } else {
+      LOG(ERROR) << "Unhandled error " << result << " in BlockingCopyHelper"
+                 << std::endl;
       // Some other error occurred.
       break;
     }
   }
 
   return false;
 }
 
 size_t CopyToStringHelper(
     std::string* result, const void* buffer, uint32_t num_bytes) {
@@ skipping 59 matching lines @@
                           std::string* result) {
   CHECK(result);
   result->clear();
   return BlockingCopyHelper(
       source.Pass(), base::Bind(&CopyToStringHelper, result));
 }
 
 bool BlockingCopyToFile(ScopedDataPipeConsumerHandle source,
                         const base::FilePath& destination) {
   base::ScopedFILE fp(base::OpenFile(destination, "wb"));
-  if (!fp)
+  if (!fp) {
+    LOG(ERROR) << "OpenFile('" << destination.value()
+               << "'failed in BlockingCopyToFile" << std::endl;
     return false;
+  }
   return BlockingCopyHelper(
       source.Pass(), base::Bind(&CopyToFileHelper, fp.get()));
 }
 
 void CopyToFile(ScopedDataPipeConsumerHandle source,
                 const base::FilePath& destination,
                 base::TaskRunner* task_runner,
                 const base::Callback<void(bool)>& callback) {
   base::PostTaskAndReplyWithResult(
       task_runner,
       FROM_HERE,
       base::Bind(&BlockingCopyToFile, base::Passed(&source), destination),
       callback);
 }
 
 void CopyFromFile(const base::FilePath& source,
                   ScopedDataPipeProducerHandle destination,
                   uint32_t skip,
                   base::TaskRunner* task_runner,
                   const base::Callback<void(bool)>& callback) {
   base::PostTaskAndReplyWithResult(task_runner, FROM_HERE,
                                    base::Bind(&BlockingCopyFromFile, source,
                                               base::Passed(&destination), skip),
                                    callback);
 }
 
 }  // namespace common
 }  // namespace mojo