AU: SplitWriter class for parsing our full update files.

src/platform/update_engine/split_file_writer_unittest.cc

+// Copyright (c) 2010 The Chromium OS 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 <algorithm>
+#include <string>
+#include <vector>
+#include <gtest/gtest.h>
+#include "update_engine/split_file_writer.h"
+#include "update_engine/test_utils.h"
+#include "update_engine/utils.h"
+
+using std::min;
+using std::string;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+class SplitFileWriterTest : public ::testing::Test {
+ protected:
+  void DoTest(size_t bytes_per_call);
+};
+
+void SplitFileWriterTest::DoTest(size_t bytes_per_call) {
+  string first_file;
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/SplitFileWriterTestFirst.XXXXXX",
+                                  &first_file,
+                                  NULL));
+  ScopedPathUnlinker first_file_unlinker(first_file);
+  string second_file;
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/SplitFileWriterTestSecond.XXXXXX",
+                                  &second_file,
+                                  NULL));
+  ScopedPathUnlinker second_file_unlinker(second_file);
+
+  // Create joined data
+  uint64_t first_bytes = 789;
+  uint64_t second_bytes = 1000;
+
+  vector<char> buf(sizeof(uint64_t) + first_bytes + second_bytes);
+  uint64_t big_endian_first_bytes = htobe64(first_bytes);
+
+  FillWithData(&buf);
+  memcpy(&buf[0], &big_endian_first_bytes, sizeof(big_endian_first_bytes));
+  
+  // Create FileWriters
+  DirectFileWriter first_file_writer;
+  DirectFileWriter second_file_writer;
+  SplitFileWriter split_file_writer(&first_file_writer, &second_file_writer);
+
+  split_file_writer.SetFirstOpenArgs(
+      first_file.c_str(), O_CREAT | O_TRUNC | O_WRONLY, 0644);
+  EXPECT_GE(split_file_writer.Open(
+      second_file.c_str(), O_CREAT | O_TRUNC | O_WRONLY, 0644), 0);
+  ScopedFileWriterCloser closer(&split_file_writer);
+
+  size_t bytes_written_total = 0;
+  for (size_t i = 0; i < buf.size(); i += bytes_per_call) {
+    size_t bytes_this_iteration = min(bytes_per_call,
+                                      buf.size() - bytes_written_total);
+    EXPECT_EQ(bytes_this_iteration,
+              split_file_writer.Write(&buf[bytes_written_total],
+                                      bytes_this_iteration));
+    bytes_written_total += bytes_this_iteration;
+  }
+  EXPECT_EQ(buf.size(), bytes_written_total);
+
+  vector<char> first_actual_data;
+  vector<char> second_actual_data;
+  EXPECT_TRUE(utils::ReadFile(first_file, &first_actual_data));
+  EXPECT_TRUE(utils::ReadFile(second_file, &second_actual_data));
+  
+  EXPECT_EQ(first_bytes, first_actual_data.size());
+  EXPECT_EQ(second_bytes, second_actual_data.size());
+
+  vector<char> first_part_from_orig(&buf[sizeof(uint64_t)],
+                                    &buf[sizeof(uint64_t) + first_bytes]);
+  vector<char> second_part_from_orig(
+      &buf[sizeof(uint64_t) + first_bytes],
+      &buf[sizeof(uint64_t) + first_bytes + second_bytes]);
+
+  EXPECT_TRUE(ExpectVectorsEq(first_part_from_orig, first_actual_data));
+  EXPECT_TRUE(ExpectVectorsEq(second_part_from_orig, second_actual_data));
+}
+
+TEST_F(SplitFileWriterTest, SimpleTest) {
+  DoTest(1024 * 1024 * 1024);  // Something very big
+}
+
+TEST_F(SplitFileWriterTest, OneByteAtATimeTest) {
+  DoTest(1);
+}
+
+TEST_F(SplitFileWriterTest, ThreeBytesAtATimeTest) {
+  DoTest(3);
+}
+
+}  // namespace chromeos_update_engine