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/*
* Copyright (C) 2008, 2009, 2010 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "StorageAreaSync.h"
#include "StorageAreaImpl.h"
#include "StorageSyncManager.h"
#include "StorageTracker.h"
#include <WebCore/SQLiteDatabaseTracker.h>
#include <WebCore/SQLiteStatement.h>
#include <WebCore/SQLiteTransaction.h>
#include <WebCore/SuddenTermination.h>
#include <wtf/FileSystem.h>
#include <wtf/MainThread.h>
using namespace WebCore;
namespace WebKit {
// If the StorageArea undergoes rapid changes, don't sync each change to disk.
// Instead, queue up a batch of items to sync and actually do the sync at the following interval.
static const Seconds StorageSyncInterval { 1_s };
// A sane limit on how many items we'll schedule to sync all at once. This makes it
// much harder to starve the rest of LocalStorage and the OS's IO subsystem in general.
static const int MaxiumItemsToSync = 100;
inline StorageAreaSync::StorageAreaSync(RefPtr<StorageSyncManager>&& storageSyncManager, Ref<StorageAreaImpl>&& storageArea, const String& databaseIdentifier)
: m_syncTimer(*this, &StorageAreaSync::syncTimerFired)
, m_itemsCleared(false)
, m_finalSyncScheduled(false)
, m_storageArea(WTFMove(storageArea))
, m_syncManager(WTFMove(storageSyncManager))
, m_databaseIdentifier(databaseIdentifier.isolatedCopy())
, m_clearItemsWhileSyncing(false)
, m_syncScheduled(false)
, m_syncInProgress(false)
, m_databaseOpenFailed(false)
, m_syncCloseDatabase(false)
, m_importComplete(false)
{
ASSERT(isMainThread());
ASSERT(m_storageArea);
ASSERT(m_syncManager);
// FIXME: If it can't import, then the default WebKit behavior should be that of private browsing,
// not silently ignoring it. https://bugs.webkit.org/show_bug.cgi?id=25894
RefPtr<StorageAreaSync> protector(this);
m_syncManager->dispatch([protector] {
protector->performImport();
});
}
Ref<StorageAreaSync> StorageAreaSync::create(RefPtr<StorageSyncManager>&& storageSyncManager, Ref<StorageAreaImpl>&& storageArea, const String& databaseIdentifier)
{
return adoptRef(*new StorageAreaSync(WTFMove(storageSyncManager), WTFMove(storageArea), databaseIdentifier));
}
StorageAreaSync::~StorageAreaSync()
{
ASSERT(isMainThread());
ASSERT(!m_syncTimer.isActive());
ASSERT(m_finalSyncScheduled);
}
void StorageAreaSync::scheduleFinalSync()
{
ASSERT(isMainThread());
// FIXME: We do this to avoid races, but it'd be better to make things safe without blocking.
blockUntilImportComplete();
m_storageArea = nullptr; // This is done in blockUntilImportComplete() but this is here as a form of documentation that we must be absolutely sure the ref count cycle is broken.
if (m_syncTimer.isActive())
m_syncTimer.stop();
else {
// The following is balanced by the call to enableSuddenTermination in the
// syncTimerFired function.
disableSuddenTermination();
}
// FIXME: This is synchronous. We should do it on the background process, but
// we should do it safely.
m_finalSyncScheduled = true;
syncTimerFired();
RefPtr<StorageAreaSync> protector(this);
m_syncManager->dispatch([protector] {
protector->deleteEmptyDatabase();
});
}
void StorageAreaSync::scheduleItemForSync(const String& key, const String& value)
{
ASSERT(isMainThread());
ASSERT(!m_finalSyncScheduled);
m_changedItems.set(key, value);
if (!m_syncTimer.isActive()) {
m_syncTimer.startOneShot(StorageSyncInterval);
// The following is balanced by the call to enableSuddenTermination in the
// syncTimerFired function.
disableSuddenTermination();
}
}
void StorageAreaSync::scheduleClear()
{
ASSERT(isMainThread());
ASSERT(!m_finalSyncScheduled);
m_changedItems.clear();
m_itemsCleared = true;
if (!m_syncTimer.isActive()) {
m_syncTimer.startOneShot(StorageSyncInterval);
// The following is balanced by the call to enableSuddenTermination in the
// syncTimerFired function.
disableSuddenTermination();
}
}
void StorageAreaSync::scheduleCloseDatabase()
{
ASSERT(isMainThread());
ASSERT(!m_finalSyncScheduled);
if (!m_database.isOpen())
return;
m_syncCloseDatabase = true;
if (!m_syncTimer.isActive()) {
m_syncTimer.startOneShot(StorageSyncInterval);
// The following is balanced by the call to enableSuddenTermination in the
// syncTimerFired function.
disableSuddenTermination();
}
}
void StorageAreaSync::syncTimerFired()
{
ASSERT(isMainThread());
bool partialSync = false;
{
Locker locker { m_syncLock };
// Do not schedule another sync if we're still trying to complete the
// previous one. But, if we're shutting down, schedule it anyway.
if (m_syncInProgress && !m_finalSyncScheduled) {
ASSERT(!m_syncTimer.isActive());
m_syncTimer.startOneShot(StorageSyncInterval);
return;
}
if (m_itemsCleared) {
m_itemsPendingSync.clear();
m_clearItemsWhileSyncing = true;
m_itemsCleared = false;
}
HashMap<String, String>::iterator changed_it = m_changedItems.begin();
HashMap<String, String>::iterator changed_end = m_changedItems.end();
for (int count = 0; changed_it != changed_end; ++count, ++changed_it) {
if (count >= MaxiumItemsToSync && !m_finalSyncScheduled) {
partialSync = true;
break;
}
m_itemsPendingSync.set(changed_it->key.isolatedCopy(), changed_it->value.isolatedCopy());
}
if (partialSync) {
// We can't do the fast path of simply clearing all items, so we'll need to manually
// remove them one by one. Done under lock since m_itemsPendingSync is modified by
// the background thread.
HashMap<String, String>::iterator pending_it = m_itemsPendingSync.begin();
HashMap<String, String>::iterator pending_end = m_itemsPendingSync.end();
for (; pending_it != pending_end; ++pending_it)
m_changedItems.remove(pending_it->key);
}
if (!m_syncScheduled) {
m_syncScheduled = true;
// The following is balanced by the call to enableSuddenTermination in the
// performSync function.
disableSuddenTermination();
RefPtr<StorageAreaSync> protector(this);
m_syncManager->dispatch([protector] {
protector->performSync();
});
}
}
if (partialSync) {
// If we didn't finish syncing, then we need to finish the job later.
ASSERT(!m_syncTimer.isActive());
m_syncTimer.startOneShot(StorageSyncInterval);
} else {
// The following is balanced by the calls to disableSuddenTermination in the
// scheduleItemForSync, scheduleClear, and scheduleFinalSync functions.
enableSuddenTermination();
m_changedItems.clear();
}
}
void StorageAreaSync::openDatabase(OpenDatabaseParamType openingStrategy)
{
ASSERT(!isMainThread());
ASSERT(!m_database.isOpen());
ASSERT(!m_databaseOpenFailed);
SQLiteTransactionInProgressAutoCounter transactionCounter;
String databaseFilename = m_syncManager->fullDatabaseFilename(m_databaseIdentifier);
if (!FileSystem::fileExists(databaseFilename) && openingStrategy == SkipIfNonExistent)
return;
if (databaseFilename.isEmpty()) {
LOG_ERROR("Filename for local storage database is empty - cannot open for persistent storage");
markImported();
m_databaseOpenFailed = true;
return;
}
// A StorageTracker thread may have been scheduled to delete the db we're
// reopening, so cancel possible deletion.
StorageTracker::tracker().cancelDeletingOrigin(m_databaseIdentifier);
if (!m_database.open(databaseFilename)) {
LOG_ERROR("Failed to open database file %s for local storage", databaseFilename.utf8().data());
markImported();
m_databaseOpenFailed = true;
return;
}
migrateItemTableIfNeeded();
if (!m_database.executeCommand("CREATE TABLE IF NOT EXISTS ItemTable (key TEXT UNIQUE ON CONFLICT REPLACE, value BLOB NOT NULL ON CONFLICT FAIL)"_s)) {
LOG_ERROR("Failed to create table ItemTable for local storage");
markImported();
m_databaseOpenFailed = true;
return;
}
StorageTracker::tracker().setOriginDetails(m_databaseIdentifier, databaseFilename);
}
void StorageAreaSync::migrateItemTableIfNeeded()
{
if (!m_database.tableExists("ItemTable"))
return;
{
auto query = m_database.prepareStatement("SELECT value FROM ItemTable LIMIT 1"_s);
// this query isn't ever executed.
if (query && query->isColumnDeclaredAsBlob(0))
return;
}
// alter table for backward compliance, change the value type from TEXT to BLOB.
static const ASCIILiteral commands[] = {
"DROP TABLE IF EXISTS ItemTable2"_s,
"CREATE TABLE ItemTable2 (key TEXT UNIQUE ON CONFLICT REPLACE, value BLOB NOT NULL ON CONFLICT FAIL)"_s,
"INSERT INTO ItemTable2 SELECT * from ItemTable"_s,
"DROP TABLE ItemTable"_s,
"ALTER TABLE ItemTable2 RENAME TO ItemTable"_s,
ASCIILiteral::null(),
};
SQLiteTransaction transaction(m_database, false);
transaction.begin();
for (size_t i = 0; commands[i]; ++i) {
if (!m_database.executeCommand(commands[i])) {
LOG_ERROR("Failed to migrate table ItemTable for local storage when executing: %s", commands[i].characters());
transaction.rollback();
// finally it will try to keep a backup of ItemTable for the future restoration.
// NOTICE: this will essentially DELETE the current database, but that's better
// than continually hitting this case and never being able to use the local storage.
// if this is ever hit, it's definitely a bug.
ASSERT_NOT_REACHED();
if (!m_database.executeCommand("ALTER TABLE ItemTable RENAME TO Backup_ItemTable"_s))
LOG_ERROR("Failed to save ItemTable after migration job failed.");
return;
}
}
transaction.commit();
}
void StorageAreaSync::performImport()
{
ASSERT(!isMainThread());
ASSERT(!m_database.isOpen());
openDatabase(SkipIfNonExistent);
if (!m_database.isOpen()) {
markImported();
return;
}
auto query = m_database.prepareStatement("SELECT key, value FROM ItemTable"_s);
if (!query) {
LOG_ERROR("Unable to select items from ItemTable for local storage");
markImported();
return;
}
HashMap<String, String> itemMap;
int result = query->step();
while (result == SQLITE_ROW) {
itemMap.set(query->columnText(0), query->columnBlobAsString(1));
result = query->step();
}
if (result != SQLITE_DONE) {
LOG_ERROR("Error reading items from ItemTable for local storage");
markImported();
return;
}
m_storageArea->importItems(WTFMove(itemMap));
markImported();
}
void StorageAreaSync::markImported()
{
Locker locker { m_importLock };
m_importComplete = true;
m_importCondition.notifyOne();
}
// FIXME: In the future, we should allow use of StorageAreas while it's importing (when safe to do so).
// Blocking everything until the import is complete is by far the simplest and safest thing to do, but
// there is certainly room for safe optimization: Key/length will never be able to make use of such an
// optimization (since the order of iteration can change as items are being added). Get can return any
// item currently in the map. Get/remove can work whether or not it's in the map, but we'll need a list
// of items the import should not overwrite. Clear can also work, but it'll need to kill the import
// job first.
void StorageAreaSync::blockUntilImportComplete()
{
ASSERT(isMainThread());
// Fast path. We set m_storageArea to 0 only after m_importComplete being true.
if (!m_storageArea)
return;
Locker locker { m_importLock };
while (!m_importComplete)
m_importCondition.wait(m_importLock);
m_storageArea = nullptr;
}
void StorageAreaSync::sync(bool clearItems, const HashMap<String, String>& items)
{
ASSERT(!isMainThread());
if (items.isEmpty() && !clearItems && !m_syncCloseDatabase)
return;
if (m_databaseOpenFailed)
return;
if (!m_database.isOpen() && m_syncCloseDatabase) {
m_syncCloseDatabase = false;
return;
}
if (!m_database.isOpen())
openDatabase(CreateIfNonExistent);
if (!m_database.isOpen())
return;
// Closing this db because it is about to be deleted by StorageTracker.
// The delete will be cancelled if StorageAreaSync needs to reopen the db
// to write new items created after the request to delete the db.
if (m_syncCloseDatabase) {
m_syncCloseDatabase = false;
m_database.close();
return;
}
SQLiteTransactionInProgressAutoCounter transactionCounter;
// If the clear flag is set, then we clear all items out before we write any new ones in.
if (clearItems) {
auto clear = m_database.prepareStatement("DELETE FROM ItemTable"_s);
if (!clear) {
LOG_ERROR("Failed to prepare clear statement - cannot write to local storage database");
return;
}
int result = clear->step();
if (result != SQLITE_DONE) {
LOG_ERROR("Failed to clear all items in the local storage database - %i", result);
return;
}
}
auto insert = m_database.prepareStatement("INSERT INTO ItemTable VALUES (?, ?)"_s);
if (!insert) {
LOG_ERROR("Failed to prepare insert statement - cannot write to local storage database");
return;
}
auto remove = m_database.prepareStatement("DELETE FROM ItemTable WHERE key=?"_s);
if (!remove) {
LOG_ERROR("Failed to prepare delete statement - cannot write to local storage database");
return;
}
HashMap<String, String>::const_iterator end = items.end();
SQLiteTransaction transaction(m_database);
transaction.begin();
for (HashMap<String, String>::const_iterator it = items.begin(); it != end; ++it) {
// Based on the null-ness of the second argument, decide whether this is an insert or a delete.
auto& query = it->value.isNull() ? remove : insert;
query->bindText(1, it->key);
// If the second argument is non-null, we're doing an insert, so bind it as the value.
if (!it->value.isNull())
query->bindBlob(2, it->value);
int result = query->step();
if (result != SQLITE_DONE) {
LOG_ERROR("Failed to update item in the local storage database - %i", result);
break;
}
query->reset();
}
transaction.commit();
}
void StorageAreaSync::performSync()
{
ASSERT(!isMainThread());
bool clearItems;
HashMap<String, String> items;
{
Locker locker { m_syncLock };
ASSERT(m_syncScheduled);
clearItems = m_clearItemsWhileSyncing;
m_itemsPendingSync.swap(items);
m_clearItemsWhileSyncing = false;
m_syncScheduled = false;
m_syncInProgress = true;
}
sync(clearItems, items);
{
Locker locker { m_syncLock };
m_syncInProgress = false;
}
// The following is balanced by the call to disableSuddenTermination in the
// syncTimerFired function.
enableSuddenTermination();
}
void StorageAreaSync::deleteEmptyDatabase()
{
ASSERT(!isMainThread());
if (!m_database.isOpen())
return;
auto count = [&] {
auto query = m_database.prepareStatement("SELECT COUNT(*) FROM ItemTable"_s);
if (!query) {
LOG_ERROR("Unable to count number of rows in ItemTable for local storage");
return -1;
}
int result = query->step();
if (result != SQLITE_ROW) {
LOG_ERROR("No results when counting number of rows in ItemTable for local storage");
return -1;
}
return query->columnInt(0);
}();
if (count)
return;
m_database.close();
if (StorageTracker::tracker().isActive()) {
callOnMainThread([databaseIdentifier = m_databaseIdentifier.isolatedCopy()] {
StorageTracker::tracker().deleteOriginWithIdentifier(databaseIdentifier);
});
} else {
String databaseFilename = m_syncManager->fullDatabaseFilename(m_databaseIdentifier);
if (!FileSystem::deleteFile(databaseFilename))
LOG_ERROR("Failed to delete database file %s\n", databaseFilename.utf8().data());
}
}
void StorageAreaSync::scheduleSync()
{
syncTimerFired();
}
} // namespace WebCore