Refactor minidump test utilities for MinidumpWritable, …

minidump/minidump_file_writer_test.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 18 matching lines @@
 namespace crashpad {
 namespace test {
 namespace {
 
 TEST(MinidumpFileWriter, Empty) {
   MinidumpFileWriter minidump_file;
   StringFileWriter file_writer;
   ASSERT_TRUE(minidump_file.WriteEverything(&file_writer));
   ASSERT_EQ(sizeof(MINIDUMP_HEADER), file_writer.string().size());
 
+  const MINIDUMP_DIRECTORY* directory;
   const MINIDUMP_HEADER* header =
-      reinterpret_cast<const MINIDUMP_HEADER*>(&file_writer.string()[0]);
-
+      MinidumpHeaderAtStart(file_writer.string(), &directory);
   ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 0, 0));
+  EXPECT_FALSE(directory);
 }
 
 class TestStream final : public internal::MinidumpStreamWriter {
  public:
   TestStream(MinidumpStreamType stream_type,
              size_t stream_size,
              uint8_t stream_value)
       : stream_data_(stream_size, stream_value), stream_type_(stream_type) {}
 
   ~TestStream() {}
@@ skipping 35 matching lines @@
 
   StringFileWriter file_writer;
   ASSERT_TRUE(minidump_file.WriteEverything(&file_writer));
 
   const size_t kDirectoryOffset = sizeof(MINIDUMP_HEADER);
   const size_t kStreamOffset = kDirectoryOffset + sizeof(MINIDUMP_DIRECTORY);
   const size_t kFileSize = kStreamOffset + kStreamSize;
 
   ASSERT_EQ(kFileSize, file_writer.string().size());
 
+  const MINIDUMP_DIRECTORY* directory;
   const MINIDUMP_HEADER* header =
-      reinterpret_cast<const MINIDUMP_HEADER*>(&file_writer.string()[0]);
+      MinidumpHeaderAtStart(file_writer.string(), &directory);
+  ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, kTimestamp));
+  ASSERT_TRUE(directory);
 
-  ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, kTimestamp));
-
-  const MINIDUMP_DIRECTORY* directory =
-      reinterpret_cast<const MINIDUMP_DIRECTORY*>(
-          &file_writer.string()[kDirectoryOffset]);
-
-  EXPECT_EQ(kStreamType, directory->StreamType);
-  EXPECT_EQ(kStreamSize, directory->Location.DataSize);
-  EXPECT_EQ(kStreamOffset, directory->Location.Rva);
+  EXPECT_EQ(kStreamType, directory[0].StreamType);
+  EXPECT_EQ(kStreamSize, directory[0].Location.DataSize);
+  EXPECT_EQ(kStreamOffset, directory[0].Location.Rva);
 
   const uint8_t* stream_data =
       reinterpret_cast<const uint8_t*>(&file_writer.string()[kStreamOffset]);
 
   std::string expected_stream(kStreamSize, kStreamValue);
   EXPECT_EQ(0, memcmp(stream_data, expected_stream.c_str(), kStreamSize));
 }
 
 TEST(MinidumpFileWriter, ThreeStreams) {
   MinidumpFileWriter minidump_file;
@@ skipping 28 matching lines @@
   const size_t kStream1Offset =
       kDirectoryOffset + 3 * sizeof(MINIDUMP_DIRECTORY);
   const size_t kStream2Padding = 3;
   const size_t kStream2Offset = kStream1Offset + kStream1Size + kStream2Padding;
   const size_t kStream3Padding = 1;
   const size_t kStream3Offset = kStream2Offset + kStream2Size + kStream3Padding;
   const size_t kFileSize = kStream3Offset + kStream3Size;
 
   ASSERT_EQ(kFileSize, file_writer.string().size());
 
+  const MINIDUMP_DIRECTORY* directory;
   const MINIDUMP_HEADER* header =
-      reinterpret_cast<const MINIDUMP_HEADER*>(&file_writer.string()[0]);
-
+      MinidumpHeaderAtStart(file_writer.string(), &directory);
   ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 3, kTimestamp));
-
-  const MINIDUMP_DIRECTORY* directory =
-      reinterpret_cast<const MINIDUMP_DIRECTORY*>(
-          &file_writer.string()[kDirectoryOffset]);
+  ASSERT_TRUE(directory);
 
   EXPECT_EQ(kStream1Type, directory[0].StreamType);
   EXPECT_EQ(kStream1Size, directory[0].Location.DataSize);
   EXPECT_EQ(kStream1Offset, directory[0].Location.Rva);
   EXPECT_EQ(kStream2Type, directory[1].StreamType);
   EXPECT_EQ(kStream2Size, directory[1].Location.DataSize);
   EXPECT_EQ(kStream2Offset, directory[1].Location.Rva);
   EXPECT_EQ(kStream3Type, directory[2].StreamType);
   EXPECT_EQ(kStream3Size, directory[2].Location.DataSize);
   EXPECT_EQ(kStream3Offset, directory[2].Location.Rva);
@@ skipping 34 matching lines @@
 
   StringFileWriter file_writer;
   ASSERT_TRUE(minidump_file.WriteEverything(&file_writer));
 
   const size_t kDirectoryOffset = sizeof(MINIDUMP_HEADER);
   const size_t kStreamOffset = kDirectoryOffset + sizeof(MINIDUMP_DIRECTORY);
   const size_t kFileSize = kStreamOffset + kStreamSize;
 
   ASSERT_EQ(kFileSize, file_writer.string().size());
 
+  const MINIDUMP_DIRECTORY* directory;
   const MINIDUMP_HEADER* header =
-      reinterpret_cast<const MINIDUMP_HEADER*>(&file_writer.string()[0]);
+      MinidumpHeaderAtStart(file_writer.string(), &directory);
+  ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, 0));
+  ASSERT_TRUE(directory);
 
-  ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, 0));
-
-  const MINIDUMP_DIRECTORY* directory =
-      reinterpret_cast<const MINIDUMP_DIRECTORY*>(
-          &file_writer.string()[kDirectoryOffset]);
-
-  EXPECT_EQ(kStreamType, directory->StreamType);
-  EXPECT_EQ(kStreamSize, directory->Location.DataSize);
-  EXPECT_EQ(kStreamOffset, directory->Location.Rva);
+  EXPECT_EQ(kStreamType, directory[0].StreamType);
+  EXPECT_EQ(kStreamSize, directory[0].Location.DataSize);
+  EXPECT_EQ(kStreamOffset, directory[0].Location.Rva);
 }
 
 TEST(MinidumpFileWriterDeathTest, SameStreamType) {
   MinidumpFileWriter minidump_file;
 
   const size_t kStream1Size = 5;
   const MinidumpStreamType kStream1Type = static_cast<MinidumpStreamType>(0x4d);
   const uint8_t kStream1Value = 0x5a;
   TestStream stream1(kStream1Type, kStream1Size, kStream1Value);
   minidump_file.AddStream(&stream1);
 
   // It is an error to add a second stream of the same type.
   const size_t kStream2Size = 3;
   const MinidumpStreamType kStream2Type = static_cast<MinidumpStreamType>(0x4d);
   const uint8_t kStream2Value = 0xa5;
   TestStream stream2(kStream2Type, kStream2Size, kStream2Value);
   ASSERT_DEATH(minidump_file.AddStream(&stream2), "already present");
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad