Initial version of new file wrapper

webrtc/base/file_win.cc

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/base/file.h"
+
+#include <io.h>
+
+#include <limits>
+
+#include "webrtc/base/checks.h"
+
+#if defined(WEBRTC_WIN)
+#include <windows.h>
+#endif
+
+namespace rtc {
+
+size_t File::WriteNoBestEffort(const uint8_t* data, size_t length) {
+  RTC_CHECK_LT(length, std::numeric_limits<DWORD>::max());
+  DWORD bytes_written;
+  if (::WriteFile(file_, data, static_cast<DWORD>(length), &bytes_written,
+                  nullptr))
+    return bytes_written;
+  return 0;
+}
+
+size_t File::ReadNoBestEffort(uint8_t* buffer, size_t length) {
+  RTC_CHECK_LT(length, std::numeric_limits<DWORD>::max());
+  DWORD bytes_read;
+  if (::ReadFile(file_, buffer, static_cast<DWORD>(length), &bytes_read,
+                 nullptr))
+    return bytes_read;
+  return 0;
+}
+
+size_t File::WriteAtNoBestEffort(const uint8_t* data,
+                                 size_t length,
+                                 size_t offset) {
+  RTC_CHECK_LT(length, std::numeric_limits<DWORD>::max());
+  LARGE_INTEGER offset_li;
+  offset_li.QuadPart = offset;
+
+  OVERLAPPED overlapped = {0};
+  overlapped.Offset = offset_li.LowPart;
+  overlapped.OffsetHigh = offset_li.HighPart;
+
+  DWORD bytes_written;
+  if (::WriteFile(file_, data, static_cast<DWORD>(length), &bytes_written,
+                  &overlapped)) {
+    return bytes_written;
+  }
+  return 0;
+}
+
+size_t File::ReadAtNoBestEffort(uint8_t* data, size_t length, size_t offset) {
+  RTC_CHECK_LT(length, std::numeric_limits<DWORD>::max());
+  LARGE_INTEGER offset_li;
+  offset_li.QuadPart = offset;
+
+  OVERLAPPED overlapped = {0};
+  overlapped.Offset = offset_li.LowPart;
+  overlapped.OffsetHigh = offset_li.HighPart;
+
+  DWORD bytes_read;
+  if (::ReadFile(file_, data, static_cast<DWORD>(length), &bytes_read,
+                 &overlapped)) {
+    return bytes_read;
+  }
+  return 0;
+}
+
+bool File::Seek(size_t offset) {
+  LARGE_INTEGER distance;
+  distance.QuadPart = offset;
+  return SetFilePointerEx(file_, distance, nullptr, FILE_BEGIN) != 0;
+}
+
+bool File::Close() {
+  if (file_ == rtc::kInvalidPlatformFileValue)
+    return false;
+  bool ret = CloseHandle(file_) != 0;
+  file_ = rtc::kInvalidPlatformFileValue;
+  return ret;
+}
+
+}  // namespace rtc