Extend WavReader and WavWriter API.

Add ability to read and write wav files using rtc::PlatformFile instead
of file name.

Bug: webrtc:8946
Change-Id: If18d9465f2155a33547f800edbdac45971a0e878
Reviewed-on: https://webrtc-review.googlesource.com/61424
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22497}

rtc_base/platform_file_unittest.cc

@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) 2018 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 "rtc_base/platform_file.h"
+#include "test/gtest.h"
+#include "test/testsupport/fileutils.h"
+
+namespace rtc {
+
+void FillWithDummyDataAndClose(FILE* const file, const std::string& filename) {
+  EXPECT_GT(fprintf(file, "%s", "Dummy data"), 0)
+      << "Failed to write to file: " << filename;
+  fclose(file);
+}
+
+TEST(PlatformFileTest, CreateWriteAndDelete) {
+  const std::string filename = webrtc::test::GenerateTempFilename(
+      webrtc::test::OutputPath(), ".testfile");
+  const PlatformFile fd = rtc::CreatePlatformFile(filename);
+  ASSERT_NE(fd, rtc::kInvalidPlatformFileValue)
+      << "Failed to create file descriptor for file: " << filename;
+  FILE* const file = rtc::FdopenPlatformFile(fd, "w");
+  ASSERT_TRUE(file != nullptr) << "Failed to open file: " << filename;
+  FillWithDummyDataAndClose(file, filename);
+  webrtc::test::RemoveFile(filename);
+}
+
+TEST(PlatformFileTest, OpenExistingWriteAndDelete) {
+  const std::string filename = webrtc::test::GenerateTempFilename(
+      webrtc::test::OutputPath(), ".testfile");
+
+  // Create file with dummy data.
+  FILE* file = fopen(filename.c_str(), "wb");
+  ASSERT_TRUE(file != nullptr) << "Failed to open file: " << filename;
+  FillWithDummyDataAndClose(file, filename);
+
+  // Open it for write, write and delete.
+  const PlatformFile fd = rtc::OpenPlatformFile(filename);
+  ASSERT_NE(fd, rtc::kInvalidPlatformFileValue)
+      << "Failed to open file descriptor for file: " << filename;
+  file = rtc::FdopenPlatformFile(fd, "w");
+  ASSERT_TRUE(file != nullptr) << "Failed to open file: " << filename;
+  FillWithDummyDataAndClose(file, filename);
+  webrtc::test::RemoveFile(filename);
+}
+
+TEST(PlatformFileTest, OpenExistingReadOnlyAndDelete) {
+  const std::string filename = webrtc::test::GenerateTempFilename(
+      webrtc::test::OutputPath(), ".testfile");
+
+  // Create file with dummy data.
+  FILE* file = fopen(filename.c_str(), "wb");
+  ASSERT_TRUE(file != nullptr) << "Failed to open file: " << filename;
+  FillWithDummyDataAndClose(file, filename);
+
+  // Open it for read, read and delete.
+  const PlatformFile fd = rtc::OpenPlatformFileReadOnly(filename);
+  ASSERT_NE(fd, rtc::kInvalidPlatformFileValue)
+      << "Failed to open file descriptor for file: " << filename;
+  file = rtc::FdopenPlatformFile(fd, "r");
+  ASSERT_TRUE(file != nullptr) << "Failed to open file: " << filename;
+
+  int buf[]{0};
+  ASSERT_GT(fread(&buf, 1, 1, file), 0u)
+      << "Failed to read from file: " << filename;
+  fclose(file);
+  webrtc::test::RemoveFile(filename);
+}
+
+}  // namespace rtc