extensions/browser/api/storage/local_value_store_cache.cc

// Copyright 2014 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 "extensions/browser/api/storage/local_value_store_cache.h"

#include <limits>

#include "base/bind.h"
#include "base/callback.h"
#include "base/files/file_path.h"
#include "content/public/browser/browser_thread.h"
#include "extensions/browser/api/storage/settings_storage_factory.h"
#include "extensions/browser/api/storage/settings_storage_quota_enforcer.h"
#include "extensions/browser/api/storage/weak_unlimited_settings_storage.h"
#include "extensions/browser/value_store/value_store.h"
#include "extensions/common/api/storage.h"
#include "extensions/common/constants.h"
#include "extensions/common/extension.h"
#include "extensions/common/permissions/api_permission.h"
#include "extensions/common/permissions/permissions_data.h"

using content::BrowserThread;

namespace extensions {

namespace {

// Returns the quota limit for local storage, taken from the schema in
// extensions/common/api/storage.json.
SettingsStorageQuotaEnforcer::Limits GetLocalQuotaLimits() {
  SettingsStorageQuotaEnforcer::Limits limits = {
    static_cast<size_t>(core_api::storage::local::QUOTA_BYTES),
    std::numeric_limits<size_t>::max(),
    std::numeric_limits<size_t>::max()
  };
  return limits;
}

}  // namespace

LocalValueStoreCache::LocalValueStoreCache(
    const scoped_refptr<SettingsStorageFactory>& factory,
    const base::FilePath& profile_path)
    : storage_factory_(factory),
      extension_base_path_(
          profile_path.AppendASCII(kLocalExtensionSettingsDirectoryName)),
      app_base_path_(profile_path.AppendASCII(kLocalAppSettingsDirectoryName)),
      quota_(GetLocalQuotaLimits()) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
}

LocalValueStoreCache::~LocalValueStoreCache() {
  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
}

void LocalValueStoreCache::RunWithValueStoreForExtension(
    const StorageCallback& callback,
    scoped_refptr<const Extension> extension) {
  DCHECK_CURRENTLY_ON(BrowserThread::FILE);

  ValueStore* storage = GetStorage(extension);

  // A neat way to implement unlimited storage; if the extension has the
  // unlimited storage permission, force through all calls to Set().
  if (extension->permissions_data()->HasAPIPermission(
          APIPermission::kUnlimitedStorage)) {
    WeakUnlimitedSettingsStorage unlimited_storage(storage);
    callback.Run(&unlimited_storage);
  } else {
    callback.Run(storage);
  }
}

void LocalValueStoreCache::DeleteStorageSoon(const std::string& extension_id) {
  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
  storage_map_.erase(extension_id);
  storage_factory_->DeleteDatabaseIfExists(app_base_path_, extension_id);
  storage_factory_->DeleteDatabaseIfExists(extension_base_path_, extension_id);
}

ValueStore* LocalValueStoreCache::GetStorage(
    scoped_refptr<const Extension> extension) {
  StorageMap::iterator iter = storage_map_.find(extension->id());
  if (iter != storage_map_.end())
    return iter->second.get();

  const base::FilePath& file_path =
      extension->is_app() ? app_base_path_ : extension_base_path_;
  linked_ptr<SettingsStorageQuotaEnforcer> storage(
      new SettingsStorageQuotaEnforcer(
          quota_, storage_factory_->Create(file_path, extension->id())));
  DCHECK(storage.get());

  storage_map_[extension->id()] = storage;
  return storage.get();
}

}  // namespace extensions