minidump: stronger checking for MinidumpWritableAtRVA<>()

minidump/test/minidump_writable_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_writable_test_util.h"
 
 #include <string>
 
 #include "base/strings/string16.h"
 #include "gtest/gtest.h"
 
 namespace crashpad {
 namespace test {
 
+namespace {
+
+//! \brief Returns an untyped minidump object located within a minidump file’s
+//!     contents, where the offset of the object is known.
+//!
+//! \param[in] file_contents The contents of the minidump file.
+//! \param[in] rva The offset within the minidump file of the desired object.
+//!
+//! \return If \a rva is within the range of \a file_contents, returns a pointer
+//!     into \a file_contents at offset \a rva. Otherwise, raises a gtest
+//!     assertion failure and returns `nullptr`.
+//!
+//! Do not call this function. Use the typed version, MinidumpWritableAtRVA<>(),
+//! or another type-specific function.
 const void* MinidumpWritableAtRVAInternal(const std::string& file_contents,
                                           RVA rva) {
   if (rva >= file_contents.size()) {
     EXPECT_LT(rva, file_contents.size());
     return nullptr;
   }
 
   return &file_contents[rva];
 }
 
+}  // namespace
+
 const void* MinidumpWritableAtLocationDescriptorInternal(
     const std::string& file_contents,
     const MINIDUMP_LOCATION_DESCRIPTOR& location,
     size_t expected_size,
     bool allow_oversized_data) {
   if (location.DataSize == 0) {
     EXPECT_EQ(0u, location.Rva);
     return nullptr;
   }
 
@@ skipping 238 matching lines @@
 const MinidumpModuleCodeViewRecordPDB70*
 MinidumpWritableAtLocationDescriptor<MinidumpModuleCodeViewRecordPDB70>(
     const std::string& file_contents,
     const MINIDUMP_LOCATION_DESCRIPTOR& location) {
   return MinidumpCVPDBAtLocationDescriptor<MinidumpModuleCodeViewRecordPDB70>(
       file_contents, location);
 }
 
 }  // namespace test
 }  // namespace crashpad