Refactor minidump test utilities for MinidumpWritable, …

minidump/test/minidump_file_writer_test_util.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,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "minidump/test/minidump_file_writer_test_util.h"
 
 #include "gtest/gtest.h"
+#include "minidump/test/minidump_writable_test_util.h"
 
 namespace crashpad {
 namespace test {
 
+const MINIDUMP_HEADER* MinidumpHeaderAtStart(
+    const std::string& file_contents,
+    const MINIDUMP_DIRECTORY** directory) {
+  MINIDUMP_LOCATION_DESCRIPTOR location_descriptor;
+  location_descriptor.DataSize = sizeof(MINIDUMP_HEADER);
+  location_descriptor.Rva = 0;
+
+  const MINIDUMP_HEADER* header =
+      MinidumpWritableAtLocationDescriptor<MINIDUMP_HEADER>(
+          file_contents, location_descriptor);
+
+  if (header) {
+    if (header->Signature != MINIDUMP_SIGNATURE) {
+      EXPECT_EQ(static_cast<uint32_t>(MINIDUMP_SIGNATURE), header->Signature);
+      return nullptr;
+    }
+    if (header->Version != MINIDUMP_VERSION) {
+      EXPECT_EQ(static_cast<uint32_t>(MINIDUMP_VERSION), header->Version);
+      return nullptr;
+    }
+
+    location_descriptor.DataSize =
+        header->NumberOfStreams * sizeof(MINIDUMP_DIRECTORY);
+    location_descriptor.Rva = header->StreamDirectoryRva;
+    *directory = MinidumpWritableAtLocationDescriptor<MINIDUMP_DIRECTORY>(
+        file_contents, location_descriptor);
+  } else {
+    *directory = nullptr;
+  }
+
+  return header;
+}
+
 void VerifyMinidumpHeader(const MINIDUMP_HEADER* header,
                           uint32_t streams,
                           uint32_t timestamp) {
+  ASSERT_TRUE(header);
   EXPECT_EQ(static_cast<uint32_t>(MINIDUMP_SIGNATURE), header->Signature);
   EXPECT_EQ(static_cast<uint32_t>(MINIDUMP_VERSION), header->Version);
   ASSERT_EQ(streams, header->NumberOfStreams);
   ASSERT_EQ(streams ? sizeof(MINIDUMP_HEADER) : 0u, header->StreamDirectoryRva);
   EXPECT_EQ(0u, header->CheckSum);
   EXPECT_EQ(timestamp, header->TimeDateStamp);
   EXPECT_EQ(MiniDumpNormal, header->Flags);
 }
 
 }  // namespace test
 }  // namespace crashpad