/*
 * Copyright (C) 2011 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. AND ITS CONTRIBUTORS ``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 ITS 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 "StorageTracker.h"

#include "StorageThread.h"
#include "StorageTrackerClient.h"
#include "WebStorageNamespaceProvider.h"
#include <WebCore/SQLiteDatabaseTracker.h>
#include <WebCore/SQLiteStatement.h>
#include <WebCore/SecurityOrigin.h>
#include <WebCore/SecurityOriginData.h>
#include <pal/text/TextEncoding.h>
#include <wtf/FileSystem.h>
#include <wtf/MainThread.h>
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>
#include <wtf/text/CString.h>

#if PLATFORM(IOS_FAMILY)
#include <pal/spi/ios/SQLite3SPI.h>
#endif

using namespace WebCore;

namespace WebKit {

static StorageTracker* storageTracker = nullptr;

// If there is no document referencing a storage database, close the underlying database
// after it has been idle for m_StorageDatabaseIdleInterval seconds.
static const Seconds defaultStorageDatabaseIdleInterval { 300_s };
    
void StorageTracker::initializeTracker(const String& storagePath, StorageTrackerClient* client)
{
    ASSERT(isMainThread());
    ASSERT(!storageTracker || !storageTracker->m_client);
    
    if (!storageTracker)
        storageTracker = new StorageTracker(storagePath);
    
    storageTracker->m_client = client;
    storageTracker->m_needsInitialization = true;
}

void StorageTracker::internalInitialize()
{
    m_needsInitialization = false;

    ASSERT(isMainThread());

    // Make sure text encoding maps have been built on the main thread, as the StorageTracker thread might try to do it there instead.
    // FIXME (<rdar://problem/9127819>): Is there a more explicit way of doing this besides accessing the UTF8Encoding?
    PAL::UTF8Encoding();
    
    storageTracker->setIsActive(true);
    storageTracker->m_thread->start();  
    storageTracker->importOriginIdentifiers();

    m_thread->dispatch([this] {
        FileSystem::deleteFile(FileSystem::pathByAppendingComponent(m_storageDirectoryPath, "StorageTracker.db"_s));
    });
}

StorageTracker& StorageTracker::tracker()
{
    if (!storageTracker)
        storageTracker = new StorageTracker(emptyString());
    if (storageTracker->m_needsInitialization)
        storageTracker->internalInitialize();
    
    return *storageTracker;
}

StorageTracker::StorageTracker(const String& storagePath)
    : m_storageDirectoryPath(storagePath.isolatedCopy())
    , m_client(0)
    , m_thread(makeUnique<StorageThread>())
    , m_isActive(false)
    , m_needsInitialization(false)
    , m_StorageDatabaseIdleInterval(defaultStorageDatabaseIdleInterval)
{
}

String StorageTracker::trackerDatabasePath()
{
    ASSERT(!m_databaseMutex.tryLock());
    return FileSystem::pathByAppendingComponent(m_storageDirectoryPath, "LegacyStorageTracker.db"_s);
}

static bool ensureDatabaseFileExists(const String& fileName, bool createIfDoesNotExist)
{
    if (createIfDoesNotExist)
        return FileSystem::makeAllDirectories(FileSystem::parentPath(fileName));

    return FileSystem::fileExists(fileName);
}

void StorageTracker::openTrackerDatabase(bool createIfDoesNotExist)
{
    ASSERT(m_isActive);
    ASSERT(!isMainThread());

    SQLiteTransactionInProgressAutoCounter transactionCounter;

    ASSERT(!m_databaseMutex.tryLock());

    if (m_database.isOpen())
        return;
    
    String databasePath = trackerDatabasePath();
    
    if (!ensureDatabaseFileExists(databasePath, createIfDoesNotExist)) {
        if (createIfDoesNotExist)
            LOG_ERROR("Failed to create database file '%s'", databasePath.ascii().data());
        return;
    }
    
    if (!m_database.open(databasePath)) {
        LOG_ERROR("Failed to open databasePath %s.", databasePath.ascii().data());
        return;
    }
    
    m_database.disableThreadingChecks();
    
    if (!m_database.tableExists("Origins"_s)) {
        if (!m_database.executeCommand("CREATE TABLE Origins (origin TEXT UNIQUE ON CONFLICT REPLACE, path TEXT);"_s))
            LOG_ERROR("Failed to create Origins table.");
    }
}

void StorageTracker::importOriginIdentifiers()
{   
    if (!m_isActive)
        return;
    
    ASSERT(isMainThread());
    ASSERT(m_thread);

    m_thread->dispatch([this] {
        syncImportOriginIdentifiers();
    });
}

void StorageTracker::finishedImportingOriginIdentifiers()
{
    Locker locker { m_databaseMutex };
    if (m_client)
        m_client->didFinishLoadingOrigins();
}

void StorageTracker::syncImportOriginIdentifiers()
{
    ASSERT(m_isActive);
    
    ASSERT(!isMainThread());

    {
        Locker locker { m_databaseMutex };

        // Don't force creation of StorageTracker's db just because a tracker
        // was initialized. It will be created if local storage dbs are found
        // by syncFileSystemAndTrackerDatabse() or the next time a local storage
        // db is created by StorageAreaSync.
        openTrackerDatabase(false);

        if (m_database.isOpen()) {
            SQLiteTransactionInProgressAutoCounter transactionCounter;

            auto statement = m_database.prepareStatement("SELECT origin FROM Origins"_s);
            if (!statement) {
                LOG_ERROR("Failed to prepare statement.");
                return;
            }
            
            int result;
            
            {
                Locker lockOrigins { m_originSetMutex };
                while ((result = statement->step()) == SQLITE_ROW)
                    m_originSet.add(statement->columnText(0).isolatedCopy());
            }
            
            if (result != SQLITE_DONE) {
                LOG_ERROR("Failed to read in all origins from the database.");
                return;
            }
        }
    }
    
    syncFileSystemAndTrackerDatabase();
    
    {
        Locker locker { m_clientMutex };

        if (m_client) {
            Locker locker { m_originSetMutex };
            OriginSet::const_iterator end = m_originSet.end();
            for (OriginSet::const_iterator it = m_originSet.begin(); it != end; ++it)
                m_client->dispatchDidModifyOrigin(*it);
        }
    }

    callOnMainThread([this] {
        finishedImportingOriginIdentifiers();
    });
}
    
void StorageTracker::syncFileSystemAndTrackerDatabase()
{
    ASSERT(!isMainThread());

    SQLiteTransactionInProgressAutoCounter transactionCounter;

    ASSERT(m_isActive);

    Vector<String> fileNames;
    {
        Locker locker { m_databaseMutex };
        fileNames = FileSystem::listDirectory(m_storageDirectoryPath);
    }

    // Use a copy of m_originSet to find expired entries and to schedule their
    // deletions from disk and from m_originSet.
    OriginSet originSetCopy;
    {
        Locker locker { m_originSetMutex };
        for (OriginSet::const_iterator it = m_originSet.begin(), end = m_originSet.end(); it != end; ++it)
            originSetCopy.add((*it).isolatedCopy());
    }
    
    // Add missing StorageTracker records.
    OriginSet foundOrigins;
    String fileExtension = ".localstorage"_s;

    for (auto& fileName : fileNames) {
        if (fileName.length() <= fileExtension.length() || !fileName.endsWith(fileExtension))
            continue;

        auto filePath = FileSystem::pathByAppendingComponent(m_storageDirectoryPath, fileName);
        String originIdentifier = fileName.left(fileName.length() - fileExtension.length());
        if (!originSetCopy.contains(originIdentifier))
            syncSetOriginDetails(originIdentifier, filePath);

        foundOrigins.add(originIdentifier);
    }

    // Delete stale StorageTracker records.
    for (OriginSet::const_iterator it = originSetCopy.begin(), end = originSetCopy.end(); it != end; ++it) {
        const String& originIdentifier = *it;
        if (foundOrigins.contains(originIdentifier))
            continue;

        callOnMainThread([this, originIdentifier = originIdentifier.isolatedCopy()] {
            deleteOriginWithIdentifier(originIdentifier);
        });
    }
}

void StorageTracker::setOriginDetails(const String& originIdentifier, const String& databaseFile)
{
    if (!m_isActive)
        return;

    {
        Locker locker { m_originSetMutex };

        if (m_originSet.contains(originIdentifier))
            return;

        m_originSet.add(originIdentifier);
    }

    auto function = [this, originIdentifier = originIdentifier.isolatedCopy(), databaseFile = databaseFile.isolatedCopy()] {
        syncSetOriginDetails(originIdentifier, databaseFile);
    };

    // FIXME: This weird ping-ponging was done to fix a deadlock. We should figure out a cleaner way to avoid it instead.
    ensureOnMainThread([this, function = WTFMove(function)]() mutable {
        m_thread->dispatch(WTFMove(function));
    });
}

void StorageTracker::syncSetOriginDetails(const String& originIdentifier, const String& databaseFile)
{
    ASSERT(!isMainThread());

    SQLiteTransactionInProgressAutoCounter transactionCounter;

    Locker locker { m_databaseMutex };

    openTrackerDatabase(true);
    
    if (!m_database.isOpen())
        return;

    auto statement = m_database.prepareStatement("INSERT INTO Origins VALUES (?, ?)"_s);
    if (!statement) {
        LOG_ERROR("Unable to establish origin '%s' in the tracker", originIdentifier.ascii().data());
        return;
    } 
    
    statement->bindText(1, originIdentifier);
    statement->bindText(2, databaseFile);
    
    if (statement->step() != SQLITE_DONE)
        LOG_ERROR("Unable to establish origin '%s' in the tracker", originIdentifier.ascii().data());

    {
        Locker locker { m_originSetMutex };
        if (!m_originSet.contains(originIdentifier))
            m_originSet.add(originIdentifier);
    }

    {
        Locker locker { m_clientMutex };
        if (m_client)
            m_client->dispatchDidModifyOrigin(originIdentifier);
    }
}

Vector<SecurityOriginData> StorageTracker::origins()
{
    ASSERT(m_isActive);
    
    if (!m_isActive)
        return { };

    Locker locker { m_originSetMutex };

    Vector<SecurityOriginData> result;
    result.reserveInitialCapacity(m_originSet.size());
    for (auto& identifier : m_originSet) {
        auto origin = SecurityOriginData::fromDatabaseIdentifier(identifier);
        if (!origin) {
            ASSERT_NOT_REACHED();
            continue;
        }
        result.uncheckedAppend(origin.value());
    }
    return result;
}

void StorageTracker::deleteAllOrigins()
{
    ASSERT(m_isActive);
    ASSERT(isMainThread());
    ASSERT(m_thread);
    
    if (!m_isActive)
        return;

    {
        Locker locker { m_originSetMutex };
        willDeleteAllOrigins();
        m_originSet.clear();
    }

    WebStorageNamespaceProvider::clearLocalStorageForAllOrigins();

    m_thread->dispatch([this] {
        syncDeleteAllOrigins();
    });
}

#if PLATFORM(IOS_FAMILY)
static void truncateDatabaseFile(SQLiteDatabase& database)
{
    sqlite3_file_control(database.sqlite3Handle(), 0, SQLITE_TRUNCATE_DATABASE, 0);
}
#endif

void StorageTracker::syncDeleteAllOrigins()
{
    ASSERT(!isMainThread());

    SQLiteTransactionInProgressAutoCounter transactionCounter;
    
    Locker locker { m_databaseMutex };
    
    openTrackerDatabase(false);
    if (!m_database.isOpen())
        return;
    
    auto statement = m_database.prepareStatement("SELECT origin, path FROM Origins"_s);
    if (!statement) {
        LOG_ERROR("Failed to prepare statement.");
        return;
    }
    
    int result;
    while ((result = statement->step()) == SQLITE_ROW) {
        if (!canDeleteOrigin(statement->columnText(0)))
            continue;

        FileSystem::deleteFile(statement->columnText(1));

        {
            Locker locker { m_clientMutex };
            if (m_client)
                m_client->dispatchDidModifyOrigin(statement->columnText(0));
        }
    }
    
    if (result != SQLITE_DONE)
        LOG_ERROR("Failed to read in all origins from the database.");

    if (m_database.isOpen()) {
#if PLATFORM(IOS_FAMILY)
        truncateDatabaseFile(m_database);
#endif
        m_database.close();
    }

#if !PLATFORM(IOS_FAMILY)
    if (!FileSystem::deleteFile(trackerDatabasePath())) {
        // In the case where it is not possible to delete the database file (e.g some other program
        // like a virus scanner is accessing it), make sure to remove all entries.
        openTrackerDatabase(false);
        if (!m_database.isOpen())
            return;
        auto deleteStatement = m_database.prepareStatement("DELETE FROM Origins"_s);
        if (!deleteStatement) {
            LOG_ERROR("Unable to prepare deletion of all origins");
            return;
        }
        if (!deleteStatement->executeCommand()) {
            LOG_ERROR("Unable to execute deletion of all origins");
            return;
        }
    }
    FileSystem::deleteEmptyDirectory(m_storageDirectoryPath);
#endif
}

void StorageTracker::deleteOriginWithIdentifier(const String& originIdentifier)
{
    auto origin = SecurityOriginData::fromDatabaseIdentifier(originIdentifier);
    if (!origin) {
        ASSERT_NOT_REACHED();
        return;
    }
    deleteOrigin(origin.value());
}

void StorageTracker::deleteOrigin(const SecurityOriginData& origin)
{    
    ASSERT(m_isActive);
    ASSERT(isMainThread());
    ASSERT(m_thread);
    
    if (!m_isActive)
        return;

    // Before deleting database, we need to clear in-memory local storage data
    // in StorageArea, and to close the StorageArea db. It's possible for an
    // item to be added immediately after closing the db and cause StorageAreaSync
    // to reopen the db before the db is deleted by a StorageTracker thread.
    // In this case, reopening the db in StorageAreaSync will cancel a pending
    // StorageTracker db deletion.
    WebStorageNamespaceProvider::clearLocalStorageForOrigin(origin);

    String originId = origin.databaseIdentifier();
    
    {
        Locker locker { m_originSetMutex };
        willDeleteOrigin(originId);
        m_originSet.remove(originId);
    }

    m_thread->dispatch([this, originId = WTFMove(originId).isolatedCopy()] {
        syncDeleteOrigin(originId);
    });
}

void StorageTracker::syncDeleteOrigin(const String& originIdentifier)
{
    ASSERT(!isMainThread());

    SQLiteTransactionInProgressAutoCounter transactionCounter;

    Locker locker { m_databaseMutex };
    
    if (!canDeleteOrigin(originIdentifier)) {
        LOG_ERROR("Attempted to delete origin '%s' while it was being created\n", originIdentifier.ascii().data());
        return;
    }
    
    openTrackerDatabase(false);
    if (!m_database.isOpen())
        return;

    String path = databasePathForOrigin(originIdentifier);
    if (path.isEmpty()) {
        // It is possible to get a request from the API to delete the storage for an origin that
        // has no such storage.
        return;
    }
    
    {
        auto deleteStatement = m_database.prepareStatement("DELETE FROM Origins where origin=?"_s);
        if (!deleteStatement) {
            LOG_ERROR("Unable to prepare deletion of origin '%s'", originIdentifier.ascii().data());
            return;
        }
        deleteStatement->bindText(1, originIdentifier);
        if (!deleteStatement->executeCommand()) {
            LOG_ERROR("Unable to execute deletion of origin '%s'", originIdentifier.ascii().data());
            return;
        }
    }

    FileSystem::deleteFile(path);
    
    bool shouldDeleteTrackerFiles = false;
    {
        Locker locker { m_originSetMutex };
        m_originSet.remove(originIdentifier);
        shouldDeleteTrackerFiles = m_originSet.isEmpty();
    }

    if (shouldDeleteTrackerFiles) {
#if PLATFORM(IOS_FAMILY)
        truncateDatabaseFile(m_database);
#endif
        m_database.close();
#if !PLATFORM(IOS_FAMILY)
        FileSystem::deleteFile(trackerDatabasePath());
        FileSystem::deleteEmptyDirectory(m_storageDirectoryPath);
#endif
    }

    {
        Locker locker { m_clientMutex };
        if (m_client)
            m_client->dispatchDidModifyOrigin(originIdentifier);
    }
}
    
void StorageTracker::willDeleteAllOrigins()
{
    ASSERT(!m_originSetMutex.tryLock());

    OriginSet::const_iterator end = m_originSet.end();
    for (OriginSet::const_iterator it = m_originSet.begin(); it != end; ++it)
        m_originsBeingDeleted.add((*it).isolatedCopy());
}

void StorageTracker::willDeleteOrigin(const String& originIdentifier)
{
    ASSERT(isMainThread());
    ASSERT(!m_originSetMutex.tryLock());

    m_originsBeingDeleted.add(originIdentifier);
}
    
bool StorageTracker::canDeleteOrigin(const String& originIdentifier)
{
    ASSERT(!m_databaseMutex.tryLock());
    Locker locker { m_originSetMutex };
    return m_originsBeingDeleted.contains(originIdentifier);
}

void StorageTracker::cancelDeletingOrigin(const String& originIdentifier)
{
    if (!m_isActive)
        return;

    Locker locker { m_databaseMutex };
    {
        Locker locker { m_originSetMutex };
        if (!m_originsBeingDeleted.isEmpty())
            m_originsBeingDeleted.remove(originIdentifier);
    }
}

bool StorageTracker::isActive()
{
    return m_isActive;
}

void StorageTracker::setIsActive(bool flag)
{
    m_isActive = flag;
}
    
String StorageTracker::databasePathForOrigin(const String& originIdentifier)
{
    ASSERT(!m_databaseMutex.tryLock());
    ASSERT(m_isActive);
    
    if (!m_database.isOpen())
        return String();

    SQLiteTransactionInProgressAutoCounter transactionCounter;

    auto pathStatement = m_database.prepareStatement("SELECT path FROM Origins WHERE origin=?"_s);
    if (!pathStatement) {
        LOG_ERROR("Unable to prepare selection of path for origin '%s'", originIdentifier.ascii().data());
        return String();
    }
    pathStatement->bindText(1, originIdentifier);
    int result = pathStatement->step();
    if (result != SQLITE_ROW)
        return String();

    return pathStatement->columnText(0);
}
    
uint64_t StorageTracker::diskUsageForOrigin(SecurityOrigin* origin)
{
    if (!m_isActive)
        return 0;

    Locker locker { m_databaseMutex };

    String path = databasePathForOrigin(origin->data().databaseIdentifier());
    if (path.isEmpty())
        return 0;

    return FileSystem::fileSize(path).value_or(0);
}

} // namespace WebCore