Reland: Add some handle read/write helpers to mojo/common/test/test_utils.h

mojo/common/test/test_utils_win.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/test/test_utils.h"
+
+#include <windows.h>
+
+#include "mojo/system/embedder/platform_handle.h"
+
+namespace mojo {
+namespace test {
+
+bool BlockingWrite(const embedder::PlatformHandle& handle,
+                   const void* buffer,
+                   size_t bytes_to_write,
+                   size_t* bytes_written) {
+  OVERLAPPED overlapped = { 0 };
+  DWORD bytes_written_dword = 0;
+
+  if (!WriteFile(handle.handle, buffer, static_cast<DWORD>(bytes_to_write),
+                 &bytes_written_dword, &overlapped)) {
+    if (GetLastError() != ERROR_IO_PENDING ||
+        !GetOverlappedResult(handle.handle, &overlapped, &bytes_written_dword,
+                             TRUE)) {
+      return false;
+    }
+  }
+
+  *bytes_written = bytes_written_dword;
+  return true;
+}
+
+bool BlockingRead(const embedder::PlatformHandle& handle,
+                  void* buffer,
+                  size_t buffer_size,
+                  size_t* bytes_read) {
+  OVERLAPPED overlapped = { 0 };
+  DWORD bytes_read_dword = 0;
+
+  if (!ReadFile(handle.handle, buffer, static_cast<DWORD>(buffer_size),
+                &bytes_read_dword, &overlapped)) {
+    if (GetLastError() != ERROR_IO_PENDING ||
+        !GetOverlappedResult(handle.handle, &overlapped, &bytes_read_dword,
+                             TRUE)) {
+      return false;
+    }
+  }
+
+  *bytes_read = bytes_read_dword;
+  return true;
+}
+
+bool NonBlockingRead(const embedder::PlatformHandle& handle,
+                     void* buffer,
+                     size_t buffer_size,
+                     size_t* bytes_read) {
+  OVERLAPPED overlapped = { 0 };
+  DWORD bytes_read_dword = 0;
+
+  if (!ReadFile(handle.handle, buffer, static_cast<DWORD>(buffer_size),
+                &bytes_read_dword, &overlapped)) {
+    if (GetLastError() != ERROR_IO_PENDING)
+      return false;
+
+    CancelIo(handle.handle);
+
+    if (!GetOverlappedResult(handle.handle, &overlapped, &bytes_read_dword,
+                             TRUE)) {
+      *bytes_read = 0;
+      return true;
+    }
+  }
+
+  *bytes_read = bytes_read_dword;
+  return true;
+}
+
+}  // namespace test
+}  // namespace mojo