Refactor our SimpleIndex file format and serialization to use Pickle instead of the previously bugg…

net/disk_cache/simple/simple_index_file.cc

+// Copyright (c) 2013 The Chromium 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 "net/disk_cache/simple/simple_index_file.h"
+
+#include "base/file_util.h"
+#include "base/hash.h"
+#include "base/logging.h"
+#include "base/pickle.h"
+#include "net/disk_cache/simple/simple_disk_format.h"
+#include "net/disk_cache/simple/simple_index_util.h"
+#include "third_party/zlib/zlib.h"
+
+namespace {
+
+const uint64 kMaxEntiresInIndex = 100000000;
+
+uint32 CalculatePickleCRC(const Pickle& pickle) {
+  return crc32(crc32(0, Z_NULL, 0),
+               reinterpret_cast<const Bytef*>(pickle.payload()),
+               implicit_cast<uInt>(pickle.payload_size()));
+}
+
+}  // namespace
+
+namespace disk_cache {
+
+SimpleIndexFile::IndexMetadata::IndexMetadata() :
+    initial_magic_number_(kSimpleIndexInitialMagicNumber),
+    version_(kSimpleVersion),
+    number_of_entries_(0),
+    cache_size_(0) {}
+
+SimpleIndexFile::IndexMetadata::IndexMetadata(
+    uint64 number_of_entries, uint64 cache_size) :
+    initial_magic_number_(kSimpleIndexInitialMagicNumber),
+    version_(kSimpleVersion),
+    number_of_entries_(number_of_entries),
+    cache_size_(cache_size) {}
+
+void SimpleIndexFile::IndexMetadata::Serialize(Pickle* pickle) const {
+  DCHECK(pickle);
+  pickle->WriteUInt64(initial_magic_number_);
+  pickle->WriteUInt32(version_);
+  pickle->WriteUInt64(number_of_entries_);
+  pickle->WriteUInt64(cache_size_);
+}
+
+bool SimpleIndexFile::IndexMetadata::DeSerialize(PickleIterator* it) {
+  DCHECK(it);
+  return it->ReadUInt64(&initial_magic_number_) &&
+      it->ReadUInt32(&version_) &&
+      it->ReadUInt64(&number_of_entries_)&&
+      it->ReadUInt64(&cache_size_);
+}
+
+bool SimpleIndexFile::IndexMetadata::CheckIndexMetadata() {
+  return number_of_entries_ <= kMaxEntiresInIndex &&
+      initial_magic_number_ == disk_cache::kSimpleIndexInitialMagicNumber &&
+      version_ == disk_cache::kSimpleVersion;
+}
+
+// static
+scoped_ptr<EntrySet> SimpleIndexFile::LoadFromDisk(
+    const base::FilePath& index_filename) {
+  std::string contents;
+  if(!file_util::ReadFileToString(index_filename, &contents)) {
+    LOG(WARNING) << "Could not read Simple Index file.";
+    return scoped_ptr<EntrySet>(NULL);
+  }
+
+  Pickle pickle(contents.data(), contents.size());
+  PickleIterator pickle_it(pickle);
+
+  SimpleIndexFile::PickleHeader* header_p =
+      pickle.headerT<SimpleIndexFile::PickleHeader>();
+  const uint32 crc_read = header_p->crc;
+  const uint32 crc_calculated = CalculatePickleCRC(pickle);
+
+  if (crc_read != crc_calculated) {
+    LOG(WARNING) << "Invalid CRC in Simple Index file.";
+    return scoped_ptr<EntrySet>(NULL);
+  }
+
+  SimpleIndexFile::IndexMetadata index_metadata;
+  if (!index_metadata.DeSerialize(&pickle_it)) {
+    LOG(ERROR) << "Invalid index_metadata on Simple Cache Index.";
+    return scoped_ptr<EntrySet>(NULL);
+  }
+
+  if (!index_metadata.CheckIndexMetadata()) {
+    LOG(ERROR) << "Invalid index_metadata on Simple Cache Index.";
+    return scoped_ptr<EntrySet>(NULL);
+  }
+
+  scoped_ptr<EntrySet> index_file_entries(new EntrySet());
+  while (index_file_entries->size() < index_metadata.GetNumberOfEntries()) {
+    EntryMetadata entry_metadata;
+    if (!entry_metadata.DeSerialize(&pickle_it)) {
+      LOG(WARNING) << "Invalid EntryMetadata in Simple Index file.";
+      return scoped_ptr<EntrySet>(NULL);
+    }
+    InsertInEntrySet(entry_metadata,
+                     index_file_entries.get());
+  }
+
+  return index_file_entries.Pass();
+}
+
+// static
+scoped_ptr<Pickle> SimpleIndexFile::Serialize(
+    const SimpleIndexFile::IndexMetadata& index_metadata,
+    const EntrySet& entries) {
+  scoped_ptr<Pickle> pickle(new Pickle(sizeof(SimpleIndexFile::PickleHeader)));
+
+  index_metadata.Serialize(pickle.get());
+  for (EntrySet::const_iterator it = entries.begin();
+       it != entries.end(); ++it) {
+    it->second.Serialize(pickle.get());
+  }
+  SimpleIndexFile::PickleHeader* header_p =
+      pickle->headerT<SimpleIndexFile::PickleHeader>();
+  header_p->crc = CalculatePickleCRC(*pickle);
+  return pickle.Pass();
+}
+
+// static
+void SimpleIndexFile::WriteToDisk(const base::FilePath& index_filename,
+                                  const Pickle& pickle) {
+  const base::FilePath temp_filename =
+      index_filename.DirName().AppendASCII("index_temp");
+  int bytes_written = file_util::WriteFile(
+      temp_filename,
+      reinterpret_cast<const char*>(pickle.data()),
+      pickle.size());
+  DCHECK_EQ(bytes_written, implicit_cast<int>(pickle.size()));
+  if (bytes_written != static_cast<int>(pickle.size())) {
+    // TODO(felipeg): Add better error handling.
+    LOG(ERROR) << "Could not write Simple Cache index to temporary file: "
+               << temp_filename.value();
+    file_util::Delete(temp_filename, /* recursive = */ false);
+    return;
+  }
+  // Swap temp and index_file.
+  bool result = file_util::ReplaceFile(temp_filename, index_filename);
+  DCHECK(result);
+}
+
+}  // namespace disk_cache