Refactor minidump test utilities for MinidumpWritable, …

minidump/minidump_exception_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 26 matching lines @@
 void GetExceptionStream(const std::string& file_contents,
                         const MINIDUMP_EXCEPTION_STREAM** exception_stream) {
   const size_t kDirectoryOffset = sizeof(MINIDUMP_HEADER);
   const size_t kExceptionStreamOffset =
       kDirectoryOffset + sizeof(MINIDUMP_DIRECTORY);
   const size_t kContextOffset =
       kExceptionStreamOffset + sizeof(MINIDUMP_EXCEPTION_STREAM);
   const size_t kFileSize = kContextOffset + sizeof(MinidumpContextX86);
   ASSERT_EQ(file_contents.size(), kFileSize);
 
+  const MINIDUMP_DIRECTORY* directory;
   const MINIDUMP_HEADER* header =
-      reinterpret_cast<const MINIDUMP_HEADER*>(&file_contents[0]);
-
+      MinidumpHeaderAtStart(file_contents, &directory);
   ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, 0));
 
-  const MINIDUMP_DIRECTORY* directory =
-      reinterpret_cast<const MINIDUMP_DIRECTORY*>(
-          &file_contents[kDirectoryOffset]);
-
   ASSERT_EQ(kMinidumpStreamTypeException, directory[0].StreamType);
   ASSERT_GE(directory[0].Location.DataSize, sizeof(MINIDUMP_EXCEPTION_STREAM));
   ASSERT_EQ(kExceptionStreamOffset, directory[0].Location.Rva);
 
   *exception_stream = reinterpret_cast<const MINIDUMP_EXCEPTION_STREAM*>(
       &file_contents[kExceptionStreamOffset]);
 }
 
 // The MINIDUMP_EXCEPTION_STREAMs |expected| and |observed| are compared against
 // each other using gtest assertions. The context will be recovered from
@@ skipping 145 matching lines @@
   MinidumpExceptionWriter exception_writer;
   std::vector<uint64_t> exception_information(EXCEPTION_MAXIMUM_PARAMETERS + 1,
                                               0x5a5a5a5a5a5a5a5a);
   ASSERT_DEATH(exception_writer.SetExceptionInformation(exception_information),
                "kMaxParameters");
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad