blob: 69c678a9d6f9eeea46814b5ae792ad4134bcf8ad [file] [log] [blame]
// Copyright 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 "content/browser/dom_storage/session_storage_database.h"
#include <inttypes.h>
#include <stddef.h>
#include <utility>
#include <vector>
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/process_memory_dump.h"
#include "build/build_config.h"
#include "content/browser/dom_storage/session_storage_metadata.h"
#include "third_party/leveldatabase/env_chromium.h"
#include "third_party/leveldatabase/leveldb_chrome.h"
#include "third_party/leveldatabase/src/include/leveldb/db.h"
#include "third_party/leveldatabase/src/include/leveldb/iterator.h"
#include "third_party/leveldatabase/src/include/leveldb/options.h"
#include "third_party/leveldatabase/src/include/leveldb/status.h"
#include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
#include "url/gurl.h"
#include "url/origin.h"
namespace {
const char session_storage_uma_name[] = "SessionStorageDatabase.Open";
enum SessionStorageUMA {
SESSION_STORAGE_UMA_SUCCESS,
SESSION_STORAGE_UMA_RECREATED,
SESSION_STORAGE_UMA_RECREATE_FAIL, // Deprecated in M56 (issue 183679)
SESSION_STORAGE_UMA_RECREATE_NOT_FOUND,
SESSION_STORAGE_UMA_RECREATE_NOT_SUPPORTED,
SESSION_STORAGE_UMA_RECREATE_CORRUPTION,
SESSION_STORAGE_UMA_RECREATE_INVALID_ARGUMENT,
SESSION_STORAGE_UMA_RECREATE_IO_ERROR,
SESSION_STORAGE_UMA_MAX
};
} // namespace
// Layout of the database:
// | key | value |
// -----------------------------------------------------------------------
// | map-1- | 2 (refcount, start of map-1-* keys)|
// | map-1-a | b (a = b in map 1) |
// | ... | |
// | namespace- | dummy (start of namespace-* keys) |
// | namespace-1- (1 = namespace id)| dummy (start of namespace-1-* keys)|
// | namespace-1-origin1 | 1 (mapid) |
// | namespace-1-origin2 | 2 |
// | namespace-2- | dummy |
// | namespace-2-origin1 | 1 (shallow copy) |
// | namespace-2-origin2 | 2 (shallow copy) |
// | namespace-3- | dummy |
// | namespace-3-origin1 | 3 (deep copy) |
// | namespace-3-origin2 | 2 (shallow copy) |
// | next-map-id | 4 |
namespace content {
// This class keeps track of ongoing operations across different threads. When
// DB inconsistency is detected, we need to 1) make sure no new operations start
// 2) wait until all current operations finish, and let the last one of them
// close the DB and delete the data. The DB will remain empty for the rest of
// the run, and will be recreated during the next run. We cannot hope to recover
// during this run, since the upper layer will have a different idea about what
// should be in the database.
class SessionStorageDatabase::DBOperation {
public:
explicit DBOperation(SessionStorageDatabase* session_storage_database)
: session_storage_database_(session_storage_database) {
base::AutoLock auto_lock(session_storage_database_->db_lock_);
++session_storage_database_->operation_count_;
}
~DBOperation() {
base::AutoLock auto_lock(session_storage_database_->db_lock_);
--session_storage_database_->operation_count_;
if ((session_storage_database_->is_inconsistent_ ||
session_storage_database_->db_error_) &&
session_storage_database_->operation_count_ == 0 &&
!session_storage_database_->invalid_db_deleted_) {
// No other operations are ongoing and the data is bad -> delete it now.
session_storage_database_->db_.reset();
leveldb::DestroyDB(session_storage_database_->file_path_.AsUTF8Unsafe(),
leveldb_env::Options());
session_storage_database_->invalid_db_deleted_ = true;
}
}
private:
SessionStorageDatabase* session_storage_database_;
};
SessionStorageDatabase::SessionStorageDatabase(
const base::FilePath& file_path,
scoped_refptr<base::SequencedTaskRunner> commit_task_runner)
: RefCountedDeleteOnSequence<SessionStorageDatabase>(
std::move(commit_task_runner)),
file_path_(file_path),
db_error_(false),
is_inconsistent_(false),
invalid_db_deleted_(false),
operation_count_(0) {
DETACH_FROM_SEQUENCE(sequence_checker_);
}
SessionStorageDatabase::~SessionStorageDatabase() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
base::ScopedAllowBaseSyncPrimitives allow_base_sync_primitives;
db_.reset();
}
void SessionStorageDatabase::ReadAreaValues(
const std::string& namespace_id,
const std::vector<std::string>& original_permanent_namespace_ids,
const url::Origin& origin,
DOMStorageValuesMap* result) {
// We don't create a database if it doesn't exist. In that case, there is
// nothing to be added to the result.
if (!LazyOpen(false))
return;
DBOperation operation(this);
// While ReadAreaValues is in progress, another thread can call
// CommitAreaChanges. CommitAreaChanges might update map ref count key while
// this thread is iterating over the map ref count key. To protect the reading
// operation, create a snapshot and read from it.
leveldb::ReadOptions options;
options.snapshot = db_->GetSnapshot();
std::string map_id;
bool exists;
if (GetMapForArea(namespace_id, origin.GetURL().spec(), options, &exists,
&map_id) &&
exists)
ReadMap(map_id, options, result, false);
if (exists) {
db_->ReleaseSnapshot(options.snapshot);
return;
}
// If the area does not exist, |namespace_id| might refer to a clone that
// is not yet created. Reading from the original database is expected to be
// consistent because tasks posted on commit sequence after clone did not
// run before capturing the snapshot.
for (const auto& original_db_id : original_permanent_namespace_ids) {
map_id.clear();
if (GetMapForArea(original_db_id, origin.GetURL().spec(), options, &exists,
&map_id) &&
exists) {
ReadMap(map_id, options, result, false);
}
if (exists)
break;
}
db_->ReleaseSnapshot(options.snapshot);
}
bool SessionStorageDatabase::CommitAreaChanges(
const std::string& namespace_id,
const url::Origin& origin,
bool clear_all_first,
const DOMStorageValuesMap& changes) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// Even if |changes| is empty, we need to write the appropriate placeholders
// in the database, so that it can be later shallow-copied successfully.
if (!LazyOpen(true))
return false;
DBOperation operation(this);
leveldb::WriteBatch batch;
// Ensure that the keys "namespace-" "namespace-N" (see the schema above)
// exist.
const bool kOkIfExists = true;
if (!CreateNamespace(namespace_id, kOkIfExists, &batch))
return false;
std::string map_id;
bool exists;
if (!GetMapForArea(namespace_id, origin.GetURL().spec(),
leveldb::ReadOptions(), &exists, &map_id))
return false;
if (exists) {
int64_t ref_count;
if (!GetMapRefCount(map_id, &ref_count))
return false;
if (ref_count > 1) {
if (!DeepCopyArea(namespace_id, origin, !clear_all_first,
&map_id, &batch))
return false;
} else if (clear_all_first) {
if (!ClearMap(map_id, &batch))
return false;
}
} else {
// Map doesn't exist, create it now if needed.
if (!changes.empty()) {
if (!CreateMapForArea(namespace_id, origin, &map_id, &batch))
return false;
}
}
WriteValuesToMap(map_id, changes, &batch);
base::ScopedAllowBaseSyncPrimitives allow_base_sync_primitives;
leveldb::Status s = db_->Write(leveldb::WriteOptions(), &batch);
UMA_HISTOGRAM_ENUMERATION("SessionStorageDatabase.Commit",
leveldb_env::GetLevelDBStatusUMAValue(s),
leveldb_env::LEVELDB_STATUS_MAX);
return DatabaseErrorCheck(s.ok());
}
bool SessionStorageDatabase::CloneNamespace(
const std::string& namespace_id,
const std::string& new_namespace_id) {
// Go through all origins in the namespace |namespace_id|, create placeholders
// for them in |new_namespace_id|, and associate them with the existing maps.
// Example, data before shallow copy:
// | map-1- | 1 (refcount) |
// | map-1-a | b |
// | namespace-1- (1 = namespace id)| dummy |
// | namespace-1-origin1 | 1 (mapid) |
// Example, data after shallow copy:
// | map-1- | 2 (inc. refcount) |
// | map-1-a | b |
// | namespace-1-(1 = namespace id) | dummy |
// | namespace-1-origin1 | 1 (mapid) |
// | namespace-2- | dummy |
// | namespace-2-origin1 | 1 (mapid) << references the same map
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (!LazyOpen(true))
return false;
DBOperation operation(this);
leveldb::WriteBatch batch;
const bool kOkIfExists = false;
if (!CreateNamespace(new_namespace_id, kOkIfExists, &batch))
return false;
std::map<std::string, std::string> areas;
if (!GetAreasInNamespace(namespace_id, &areas))
return false;
for (std::map<std::string, std::string>::const_iterator it = areas.begin();
it != areas.end(); ++it) {
const std::string& origin = it->first;
const std::string& map_id = it->second;
if (!IncreaseMapRefCount(map_id, &batch))
return false;
AddAreaToNamespace(new_namespace_id, origin, map_id, &batch);
}
base::ScopedAllowBaseSyncPrimitives allow_base_sync_primitives;
leveldb::Status s = db_->Write(leveldb::WriteOptions(), &batch);
return DatabaseErrorCheck(s.ok());
}
bool SessionStorageDatabase::DeleteArea(const std::string& namespace_id,
const url::Origin& origin) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (!LazyOpen(false)) {
// No need to create the database if it doesn't exist.
return true;
}
DBOperation operation(this);
leveldb::WriteBatch batch;
if (!DeleteAreaHelper(namespace_id, origin.GetURL().spec(), &batch))
return false;
base::ScopedAllowBaseSyncPrimitives allow_base_sync_primitives;
leveldb::Status s = db_->Write(leveldb::WriteOptions(), &batch);
return DatabaseErrorCheck(s.ok());
}
bool SessionStorageDatabase::DeleteNamespace(const std::string& namespace_id) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
{
// The caller should have called other methods to open the DB before this
// function. Otherwise, DB stores nothing interesting related to the
// specified namespace.
// Do nothing if the DB is not open (or we know it has failed already),
base::AutoLock auto_lock(db_lock_);
if (!IsOpen() || db_error_ || is_inconsistent_)
return false;
}
DBOperation operation(this);
// Itereate through the areas in the namespace.
leveldb::WriteBatch batch;
std::map<std::string, std::string> areas;
if (!GetAreasInNamespace(namespace_id, &areas))
return false;
for (std::map<std::string, std::string>::const_iterator it = areas.begin();
it != areas.end(); ++it) {
const std::string& origin = it->first;
if (!DeleteAreaHelper(namespace_id, origin, &batch))
return false;
}
batch.Delete(NamespaceStartKey(namespace_id));
base::ScopedAllowBaseSyncPrimitives allow_base_sync_primitives;
leveldb::Status s = db_->Write(leveldb::WriteOptions(), &batch);
return DatabaseErrorCheck(s.ok());
}
bool SessionStorageDatabase::ReadNamespacesAndOrigins(
std::map<std::string, std::vector<url::Origin>>* namespaces_and_origins) {
if (!LazyOpen(true))
return false;
DBOperation operation(this);
// While ReadNamespacesAndOrigins is in progress, another thread can call
// CommitAreaChanges. To protect the reading operation, create a snapshot and
// read from it.
leveldb::ReadOptions options;
options.snapshot = db_->GetSnapshot();
std::string namespace_prefix = NamespacePrefix();
std::unique_ptr<leveldb::Iterator> it(db_->NewIterator(options));
it->Seek(namespace_prefix);
// If the key is not found, the status of the iterator won't be IsNotFound(),
// but the iterator will be invalid.
if (!it->Valid()) {
db_->ReleaseSnapshot(options.snapshot);
return true;
}
if (!DatabaseErrorCheck(it->status().ok())) {
db_->ReleaseSnapshot(options.snapshot);
return false;
}
// Skip the dummy entry "namespace-" and iterate the namespaces.
std::string current_namespace_start_key;
std::string current_namespace_id;
for (it->Next(); it->Valid(); it->Next()) {
std::string key = it->key().ToString();
if (!base::StartsWith(key, namespace_prefix,
base::CompareCase::SENSITIVE)) {
// Iterated past the "namespace-" keys.
break;
}
// For each namespace, the first key is "namespace-<namespaceid>-", and the
// subsequent keys are "namespace-<namespaceid>-<origin>". Read the unique
// "<namespaceid>" parts from the keys.
if (current_namespace_start_key.empty() ||
key.substr(0, current_namespace_start_key.length()) !=
current_namespace_start_key) {
// The key is of the form "namespace-<namespaceid>-" for a new
// <namespaceid>.
current_namespace_start_key = key;
current_namespace_id =
key.substr(namespace_prefix.length(),
key.length() - namespace_prefix.length() - 1);
// Ensure that we keep track of the namespace even if it doesn't contain
// any origins.
namespaces_and_origins->insert(
std::make_pair(current_namespace_id, std::vector<url::Origin>()));
} else {
// The key is of the form "namespace-<namespaceid>-<origin>".
std::string origin = key.substr(current_namespace_start_key.length());
(*namespaces_and_origins)[current_namespace_id].push_back(
url::Origin::Create(GURL(origin)));
}
}
db_->ReleaseSnapshot(options.snapshot);
return true;
}
void SessionStorageDatabase::OnMemoryDump(
base::trace_event::ProcessMemoryDump* pmd) {
base::AutoLock lock(db_lock_);
if (!db_)
return;
// All leveldb databases are already dumped by leveldb_env::DBTracker. Add
// an edge to the existing dump.
auto* tracker_dump =
leveldb_env::DBTracker::GetOrCreateAllocatorDump(pmd, db_.get());
if (!tracker_dump)
return;
auto* mad = pmd->CreateAllocatorDump(
base::StringPrintf("site_storage/session_storage/0x%" PRIXPTR,
reinterpret_cast<uintptr_t>(this)));
pmd->AddOwnershipEdge(mad->guid(), tracker_dump->guid());
mad->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
base::trace_event::MemoryAllocatorDump::kUnitsBytes,
tracker_dump->GetSizeInternal());
}
void SessionStorageDatabase::SetDatabaseForTesting(
std::unique_ptr<leveldb::DB> db) {
CHECK(!db_);
db_ = std::move(db);
}
bool SessionStorageDatabase::LazyOpen(bool create_if_needed) {
base::AutoLock auto_lock(db_lock_);
if (db_error_ || is_inconsistent_) {
// Don't try to open a database that we know has failed already.
return false;
}
if (IsOpen())
return true;
if (!create_if_needed &&
(!base::PathExists(file_path_) || base::IsDirectoryEmpty(file_path_))) {
// If the directory doesn't exist already and we haven't been asked to
// create a file on disk, then we don't bother opening the database. This
// means we wait until we absolutely need to put something onto disk before
// we do so.
return false;
}
leveldb::Status s = TryToOpen(&db_);
if (!s.ok()) {
LOG(WARNING) << "Failed to open leveldb in " << file_path_.value()
<< ", error: " << s.ToString();
// Clear the directory and try again.
s = leveldb_chrome::DeleteDB(file_path_, leveldb_env::Options());
if (!s.ok()) {
LOG(WARNING) << "Failed to delete leveldb in " << file_path_.value()
<< ", error: " << s.ToString();
}
s = TryToOpen(&db_);
if (!s.ok()) {
LOG(WARNING) << "Failed to open leveldb in " << file_path_.value()
<< ", error: " << s.ToString();
if (s.IsNotFound()) {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATE_NOT_FOUND,
SESSION_STORAGE_UMA_MAX);
} else if (s.IsNotSupportedError()) {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATE_NOT_SUPPORTED,
SESSION_STORAGE_UMA_MAX);
} else if (s.IsCorruption()) {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATE_CORRUPTION,
SESSION_STORAGE_UMA_MAX);
} else if (s.IsInvalidArgument()) {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATE_INVALID_ARGUMENT,
SESSION_STORAGE_UMA_MAX);
} else if (s.IsIOError()) {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATE_IO_ERROR,
SESSION_STORAGE_UMA_MAX);
} else {
NOTREACHED();
}
db_error_ = true;
return false;
}
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_RECREATED,
SESSION_STORAGE_UMA_MAX);
} else {
UMA_HISTOGRAM_ENUMERATION(session_storage_uma_name,
SESSION_STORAGE_UMA_SUCCESS,
SESSION_STORAGE_UMA_MAX);
}
return true;
}
leveldb::Status SessionStorageDatabase::TryToOpen(
std::unique_ptr<leveldb::DB>* db) {
leveldb_env::Options options;
// The directory exists but a valid leveldb database might not exist inside it
// (e.g., a subset of the needed files might be missing). Handle this
// situation gracefully by creating the database now.
options.max_open_files = 0; // Use minimum.
options.create_if_missing = true;
// Default write_buffer_size is 4 MB but that might leave a 3.999
// memory allocation in RAM from a log file recovery.
options.write_buffer_size = 64 * 1024;
options.block_cache = leveldb_chrome::GetSharedWebBlockCache();
std::string db_name = file_path_.AsUTF8Unsafe();
#if defined(OS_ANDROID)
// On Android there is no support for session storage restoring, and since
// the restoring code is responsible for database cleanup, we must manually
// delete the old database here before we open it.
leveldb::DestroyDB(db_name, options);
#endif
leveldb::Status s = leveldb_env::OpenDB(options, db_name, db);
if (!s.ok())
return s;
// If there is a version entry from the new implementation, treat the database
// as corrupt.
leveldb::Slice version_key =
leveldb::Slice(reinterpret_cast<const char*>(
SessionStorageMetadata::kDatabaseVersionBytes),
sizeof(SessionStorageMetadata::kDatabaseVersionBytes));
std::string dummy;
s = (*db)->Get(leveldb::ReadOptions(), version_key, &dummy);
if (s.IsNotFound())
return leveldb::Status::OK();
db->reset();
return leveldb::Status::Corruption(
"Cannot read a database that is a higher schema version.", dummy);
}
bool SessionStorageDatabase::IsOpen() const {
return db_.get() != nullptr;
}
bool SessionStorageDatabase::CallerErrorCheck(bool ok) const {
DCHECK(ok);
return ok;
}
bool SessionStorageDatabase::ConsistencyCheck(bool ok) {
if (ok)
return true;
base::AutoLock auto_lock(db_lock_);
// We cannot recover the database during this run, e.g., the upper layer can
// have a different understanding of the database state (shallow and deep
// copies). Make further operations fail. The next operation that finishes
// will delete the data, and next run will recerate the database.
is_inconsistent_ = true;
return false;
}
bool SessionStorageDatabase::DatabaseErrorCheck(bool ok) {
if (ok)
return true;
base::AutoLock auto_lock(db_lock_);
// Make further operations fail. The next operation that finishes
// will delete the data, and next run will recerate the database.
db_error_ = true;
return false;
}
bool SessionStorageDatabase::CreateNamespace(const std::string& namespace_id,
bool ok_if_exists,
leveldb::WriteBatch* batch) {
leveldb::Slice namespace_prefix = NamespacePrefix();
std::string dummy;
leveldb::Status s = db_->Get(leveldb::ReadOptions(), namespace_prefix,
&dummy);
if (!DatabaseErrorCheck(s.ok() || s.IsNotFound()))
return false;
if (s.IsNotFound())
batch->Put(namespace_prefix, "");
std::string namespace_start_key = NamespaceStartKey(namespace_id);
s = db_->Get(leveldb::ReadOptions(), namespace_start_key, &dummy);
if (!DatabaseErrorCheck(s.ok() || s.IsNotFound()))
return false;
if (s.IsNotFound()) {
batch->Put(namespace_start_key, "");
return true;
}
return CallerErrorCheck(ok_if_exists);
}
bool SessionStorageDatabase::GetAreasInNamespace(
const std::string& namespace_id,
std::map<std::string, std::string>* areas) {
std::string namespace_start_key = NamespaceStartKey(namespace_id);
std::unique_ptr<leveldb::Iterator> it(
db_->NewIterator(leveldb::ReadOptions()));
it->Seek(namespace_start_key);
// If the key is not found, the status of the iterator won't be IsNotFound(),
// but the iterator will be invalid.
if (!it->Valid()) {
// The namespace_start_key is not found when the namespace doesn't contain
// any areas. We don't need to do anything.
return true;
}
if (!DatabaseErrorCheck(it->status().ok()))
return false;
// Skip the dummy entry "namespace-<namespaceid>-" and iterate the origins.
for (it->Next(); it->Valid(); it->Next()) {
std::string key = it->key().ToString();
if (!base::StartsWith(key, namespace_start_key,
base::CompareCase::SENSITIVE)) {
// Iterated past the origins for this namespace.
break;
}
std::string origin = key.substr(namespace_start_key.length());
std::string map_id = it->value().ToString();
(*areas)[origin] = map_id;
}
return true;
}
void SessionStorageDatabase::AddAreaToNamespace(const std::string& namespace_id,
const std::string& origin,
const std::string& map_id,
leveldb::WriteBatch* batch) {
std::string namespace_key = NamespaceKey(namespace_id, origin);
batch->Put(namespace_key, map_id);
}
bool SessionStorageDatabase::DeleteAreaHelper(
const std::string& namespace_id,
const std::string& origin,
leveldb::WriteBatch* batch) {
std::string map_id;
bool exists;
if (!GetMapForArea(namespace_id, origin, leveldb::ReadOptions(), &exists,
&map_id))
return false;
if (!exists)
return true; // Nothing to delete.
if (!DecreaseMapRefCount(map_id, 1, batch))
return false;
std::string namespace_key = NamespaceKey(namespace_id, origin);
batch->Delete(namespace_key);
// If this was the only area in the namespace, delete the namespace start key,
// too.
std::string namespace_start_key = NamespaceStartKey(namespace_id);
std::unique_ptr<leveldb::Iterator> it(
db_->NewIterator(leveldb::ReadOptions()));
it->Seek(namespace_start_key);
if (!ConsistencyCheck(it->Valid()))
return false;
// Advance the iterator 2 times (we still haven't really deleted
// namespace_key).
it->Next();
if (!ConsistencyCheck(it->Valid()))
return false;
it->Next();
if (!it->Valid())
return true;
std::string key = it->key().ToString();
if (!base::StartsWith(key, namespace_start_key, base::CompareCase::SENSITIVE))
batch->Delete(namespace_start_key);
return true;
}
bool SessionStorageDatabase::GetMapForArea(const std::string& namespace_id,
const std::string& origin,
const leveldb::ReadOptions& options,
bool* exists, std::string* map_id) {
std::string namespace_key = NamespaceKey(namespace_id, origin);
leveldb::Status s = db_->Get(options, namespace_key, map_id);
if (s.IsNotFound()) {
*exists = false;
return true;
}
*exists = true;
return DatabaseErrorCheck(s.ok());
}
bool SessionStorageDatabase::CreateMapForArea(const std::string& namespace_id,
const url::Origin& origin,
std::string* map_id,
leveldb::WriteBatch* batch) {
leveldb::Slice next_map_id_key = NextMapIdKey();
leveldb::Status s = db_->Get(leveldb::ReadOptions(), next_map_id_key, map_id);
if (!DatabaseErrorCheck(s.ok() || s.IsNotFound()))
return false;
int64_t next_map_id = 0;
if (s.IsNotFound()) {
*map_id = "0";
} else {
bool conversion_ok = base::StringToInt64(*map_id, &next_map_id);
if (!ConsistencyCheck(conversion_ok))
return false;
}
batch->Put(next_map_id_key, base::NumberToString(++next_map_id));
std::string namespace_key =
NamespaceKey(namespace_id, origin.GetURL().spec());
batch->Put(namespace_key, *map_id);
batch->Put(MapRefCountKey(*map_id), "1");
return true;
}
bool SessionStorageDatabase::ReadMap(const std::string& map_id,
const leveldb::ReadOptions& options,
DOMStorageValuesMap* result,
bool only_keys) {
std::unique_ptr<leveldb::Iterator> it(db_->NewIterator(options));
std::string map_start_key = MapRefCountKey(map_id);
it->Seek(map_start_key);
// If the key is not found, the status of the iterator won't be IsNotFound(),
// but the iterator will be invalid. The map needs to exist, otherwise we have
// a stale map_id in the database.
if (!ConsistencyCheck(it->Valid()))
return false;
if (!DatabaseErrorCheck(it->status().ok()))
return false;
// Skip the dummy entry "map-<mapid>-".
for (it->Next(); it->Valid(); it->Next()) {
std::string key = it->key().ToString();
if (!base::StartsWith(key, map_start_key, base::CompareCase::SENSITIVE)) {
// Iterated past the keys in this map.
break;
}
// Key is of the form "map-<mapid>-<key>".
base::string16 key16 =
base::UTF8ToUTF16(key.substr(map_start_key.length()));
if (only_keys) {
(*result)[key16] = base::NullableString16();
} else {
// Convert the raw data stored in std::string (it->value()) to raw data
// stored in base::string16.
size_t len = it->value().size() / sizeof(base::char16);
const base::char16* data_ptr =
reinterpret_cast<const base::char16*>(it->value().data());
(*result)[key16] =
base::NullableString16(base::string16(data_ptr, len), false);
}
}
return true;
}
void SessionStorageDatabase::WriteValuesToMap(const std::string& map_id,
const DOMStorageValuesMap& values,
leveldb::WriteBatch* batch) {
for (auto it = values.begin(); it != values.end(); ++it) {
base::NullableString16 value = it->second;
std::string key = MapKey(map_id, base::UTF16ToUTF8(it->first));
if (value.is_null()) {
batch->Delete(key);
} else {
// Convert the raw data stored in base::string16 to raw data stored in
// std::string.
const char* data = reinterpret_cast<const char*>(value.string().data());
size_t size = value.string().size() * 2;
batch->Put(key, leveldb::Slice(data, size));
}
}
}
bool SessionStorageDatabase::GetMapRefCount(const std::string& map_id,
int64_t* ref_count) {
std::string ref_count_string;
leveldb::Status s = db_->Get(leveldb::ReadOptions(),
MapRefCountKey(map_id), &ref_count_string);
if (!ConsistencyCheck(s.ok()))
return false;
bool conversion_ok = base::StringToInt64(ref_count_string, ref_count);
return ConsistencyCheck(conversion_ok);
}
bool SessionStorageDatabase::IncreaseMapRefCount(const std::string& map_id,
leveldb::WriteBatch* batch) {
// Increase the ref count for the map.
int64_t old_ref_count;
if (!GetMapRefCount(map_id, &old_ref_count))
return false;
batch->Put(MapRefCountKey(map_id), base::NumberToString(++old_ref_count));
return true;
}
bool SessionStorageDatabase::DecreaseMapRefCount(const std::string& map_id,
int decrease,
leveldb::WriteBatch* batch) {
// Decrease the ref count for the map.
int64_t ref_count;
if (!GetMapRefCount(map_id, &ref_count))
return false;
if (!ConsistencyCheck(decrease <= ref_count))
return false;
ref_count -= decrease;
if (ref_count > 0) {
batch->Put(MapRefCountKey(map_id), base::NumberToString(ref_count));
} else {
// Clear all keys in the map.
if (!ClearMap(map_id, batch))
return false;
batch->Delete(MapRefCountKey(map_id));
}
return true;
}
bool SessionStorageDatabase::ClearMap(const std::string& map_id,
leveldb::WriteBatch* batch) {
DOMStorageValuesMap values;
if (!ReadMap(map_id, leveldb::ReadOptions(), &values, true))
return false;
for (DOMStorageValuesMap::const_iterator it = values.begin();
it != values.end(); ++it)
batch->Delete(MapKey(map_id, base::UTF16ToUTF8(it->first)));
return true;
}
bool SessionStorageDatabase::DeepCopyArea(const std::string& namespace_id,
const url::Origin& origin,
bool copy_data,
std::string* map_id,
leveldb::WriteBatch* batch) {
// Example, data before deep copy:
// | namespace-1- (1 = namespace id)| dummy |
// | namespace-1-origin1 | 1 (mapid) |
// | namespace-2- | dummy |
// | namespace-2-origin1 | 1 (mapid) << references the same map
// | map-1- | 2 (refcount) |
// | map-1-a | b |
// Example, data after deep copy copy:
// | namespace-1-(1 = namespace id) | dummy |
// | namespace-1-origin1 | 1 (mapid) |
// | namespace-2- | dummy |
// | namespace-2-origin1 | 2 (mapid) << references the new map
// | map-1- | 1 (dec. refcount) |
// | map-1-a | b |
// | map-2- | 1 (refcount) |
// | map-2-a | b |
// Read the values from the old map here. If we don't need to copy the data,
// this can stay empty.
DOMStorageValuesMap values;
if (copy_data && !ReadMap(*map_id, leveldb::ReadOptions(), &values, false))
return false;
if (!DecreaseMapRefCount(*map_id, 1, batch))
return false;
// Create a new map (this will also break the association to the old map) and
// write the old data into it. This will write the id of the created map into
// |map_id|.
if (!CreateMapForArea(namespace_id, origin, map_id, batch))
return false;
WriteValuesToMap(*map_id, values, batch);
return true;
}
std::string SessionStorageDatabase::NamespaceStartKey(
const std::string& namespace_id) {
return base::StringPrintf("namespace-%s-", namespace_id.c_str());
}
std::string SessionStorageDatabase::NamespaceKey(
const std::string& namespace_id, const std::string& origin) {
return base::StringPrintf("namespace-%s-%s", namespace_id.c_str(),
origin.c_str());
}
const char* SessionStorageDatabase::NamespacePrefix() {
return "namespace-";
}
std::string SessionStorageDatabase::MapRefCountKey(const std::string& map_id) {
return base::StringPrintf("map-%s-", map_id.c_str());
}
std::string SessionStorageDatabase::MapKey(const std::string& map_id,
const std::string& key) {
return base::StringPrintf("map-%s-%s", map_id.c_str(), key.c_str());
}
const char* SessionStorageDatabase::NextMapIdKey() {
return "next-map-id";
}
} // namespace content