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// 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 <memory>
#include <string>
#include <vector>
#include "base/files/file_path.h"
#include "base/gtest_prod_util.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/pickle.h"
#include "net/base/cache_type.h"
#include "net/base/net_export.h"
#include "net/disk_cache/simple/simple_index.h"
#include "starboard/types.h"
namespace base {
class SequencedTaskRunner;
class TaskRunner;
namespace disk_cache {
const uint64_t kSimpleIndexMagicNumber = UINT64_C(0x656e74657220796f);
struct NET_EXPORT_PRIVATE SimpleIndexLoadResult {
void Reset();
bool did_load;
SimpleIndex::EntrySet entries;
SimpleIndex::IndexWriteToDiskReason index_write_reason;
SimpleIndex::IndexInitMethod init_method;
bool flush_required;
// Simple Index File format is a pickle of IndexMetadata and EntryMetadata
// objects. The file format is as follows: one instance of |IndexMetadata|
// followed by |EntryMetadata| repeated |entry_count| times. To learn more about
// the format see |SimpleIndexFile::Serialize()| and
// |SimpleIndexFile::LoadFromDisk()|.
// The non-static methods must run on the IO thread. All the real
// work is done in the static methods, which are run on the cache thread
// or in worker threads. Synchronization between methods is the
// responsibility of the caller.
class NET_EXPORT_PRIVATE SimpleIndexFile {
class NET_EXPORT_PRIVATE IndexMetadata {
IndexMetadata(SimpleIndex::IndexWriteToDiskReason reason,
uint64_t entry_count,
uint64_t cache_size);
virtual void Serialize(base::Pickle* pickle) const;
bool Deserialize(base::PickleIterator* it);
bool CheckIndexMetadata();
SimpleIndex::IndexWriteToDiskReason reason() const { return reason_; }
uint64_t entry_count() const { return entry_count_; }
bool has_entry_in_memory_data() const { return version_ >= 8; }
FRIEND_TEST_ALL_PREFIXES(IndexMetadataTest, Basics);
FRIEND_TEST_ALL_PREFIXES(IndexMetadataTest, Serialize);
FRIEND_TEST_ALL_PREFIXES(IndexMetadataTest, ReadV6Format);
FRIEND_TEST_ALL_PREFIXES(SimpleIndexFileTest, ReadV7Format);
friend class V6IndexMetadataForTest;
friend class V7IndexMetadataForTest;
uint64_t magic_number_;
uint32_t version_;
SimpleIndex::IndexWriteToDiskReason reason_;
uint64_t entry_count_;
uint64_t cache_size_; // Total cache storage size in bytes.
SimpleIndexFile(const scoped_refptr<base::SequencedTaskRunner>& cache_runner,
const scoped_refptr<base::TaskRunner>& worker_pool,
net::CacheType cache_type,
const base::FilePath& cache_directory);
virtual ~SimpleIndexFile();
// Gets index entries based on current disk context. On error it may leave
// |out_result.did_load| untouched, but still return partial and consistent
// results in |out_result.entries|.
virtual void LoadIndexEntries(base::Time cache_last_modified,
const base::Closure& callback,
SimpleIndexLoadResult* out_result);
// Writes the specified set of entries to disk.
virtual void WriteToDisk(SimpleIndex::IndexWriteToDiskReason reason,
const SimpleIndex::EntrySet& entry_set,
uint64_t cache_size,
const base::TimeTicks& start,
bool app_on_background,
const base::Closure& callback);
friend class WrappedSimpleIndexFile;
// Used for cache directory traversal.
using EntryFileCallback = base::Callback<void(const base::FilePath&,
base::Time last_accessed,
base::Time last_modified,
int64_t size)>;
// When loading the entries from disk, add this many extra hash buckets to
// prevent reallocation on the IO thread when merging in new live entries.
static const int kExtraSizeForMerge = 512;
// Synchronous (IO performing) implementation of LoadIndexEntries.
static void SyncLoadIndexEntries(net::CacheType cache_type,
base::Time cache_last_modified,
const base::FilePath& cache_directory,
const base::FilePath& index_file_path,
SimpleIndexLoadResult* out_result);
// Load the index file from disk returning an EntrySet.
static void SyncLoadFromDisk(const base::FilePath& index_filename,
base::Time* out_last_cache_seen_by_index,
SimpleIndexLoadResult* out_result);
// Returns a scoped_ptr for a newly allocated base::Pickle containing the
// serialized
// data to be written to a file. Note: the pickle is not in a consistent state
// immediately after calling this menthod, one needs to call
// SerializeFinalData to make it ready to write to a file.
static std::unique_ptr<base::Pickle> Serialize(
const SimpleIndexFile::IndexMetadata& index_metadata,
const SimpleIndex::EntrySet& entries);
// Appends cache modification time data to the serialized format. This is
// performed on a thread accessing the disk. It is not combined with the main
// serialization path to avoid extra thread hops or copying the pickle to the
// worker thread.
static void SerializeFinalData(base::Time cache_modified,
base::Pickle* pickle);
// Given the contents of an index file |data| of length |data_len|, returns
// the corresponding EntrySet. Returns NULL on error.
static void Deserialize(const char* data, int data_len,
base::Time* out_cache_last_modified,
SimpleIndexLoadResult* out_result);
// Implemented either in or
// base::FileEnumerator turned out to be very
// expensive in terms of memory usage therefore it's used only on non-POSIX
// environments for convenience (for now). Returns whether the traversal
// succeeded.
static bool TraverseCacheDirectory(
const base::FilePath& cache_path,
const EntryFileCallback& entry_file_callback);
// Writes the index file to disk atomically.
static void SyncWriteToDisk(net::CacheType cache_type,
const base::FilePath& cache_directory,
const base::FilePath& index_filename,
const base::FilePath& temp_index_filename,
std::unique_ptr<base::Pickle> pickle,
const base::TimeTicks& start_time,
bool app_on_background);
// Scan the index directory for entries, returning an EntrySet of all entries
// found.
static void SyncRestoreFromDisk(const base::FilePath& cache_directory,
const base::FilePath& index_file_path,
SimpleIndexLoadResult* out_result);
// Determines if an index file is stale relative to the time of last
// modification of the cache directory. Obsolete, used only for a histogram to
// compare with the new method.
// TODO(pasko): remove this method after getting enough data.
static bool LegacyIsIndexFileStale(base::Time cache_last_modified,
const base::FilePath& index_file_path);
const scoped_refptr<base::SequencedTaskRunner> cache_runner_;
const scoped_refptr<base::TaskRunner> worker_pool_;
const net::CacheType cache_type_;
const base::FilePath cache_directory_;
const base::FilePath index_file_;
const base::FilePath temp_index_file_;
static const char kIndexDirectory[];
static const char kIndexFileName[];
static const char kTempIndexFileName[];
} // namespace disk_cache