Source/WebCore/Modules/indexeddb/server/MemoryIndexCursor.cpp

/*
 * Copyright (C) 2015 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 "config.h"
#include "MemoryIndexCursor.h"

#if ENABLE(INDEXED_DATABASE)

#include "IDBCursorInfo.h"
#include "IDBGetResult.h"
#include "IndexValueStore.h"
#include "Logging.h"
#include "MemoryCursor.h"
#include "MemoryIndex.h"
#include "MemoryObjectStore.h"

namespace WebCore {
namespace IDBServer {

MemoryIndexCursor::MemoryIndexCursor(MemoryIndex& index, const IDBCursorInfo& info)
    : MemoryCursor(info)
    , m_index(index)
{
    LOG(IndexedDB, "MemoryIndexCursor::MemoryIndexCursor %s", info.range().loggingString().utf8().data());

    auto* valueStore = m_index.valueStore();
    if (!valueStore)
        return;

    if (m_info.isDirectionForward())
        m_currentIterator = valueStore->find(m_info.range().lowerKey, m_info.range().lowerOpen);
    else
        m_currentIterator = valueStore->reverseFind(m_info.range().upperKey, m_info.duplicity(), m_info.range().upperOpen);

    if (m_currentIterator.isValid() && m_info.range().containsKey(m_currentIterator.key())) {
        m_currentKey = m_currentIterator.key();
        m_currentPrimaryKey = m_currentIterator.primaryKey();
        m_index.cursorDidBecomeClean(*this);
    } else
        m_currentIterator.invalidate();
}

MemoryIndexCursor::~MemoryIndexCursor() = default;

void MemoryIndexCursor::currentData(IDBGetResult& getResult)
{
    if (!m_currentIterator.isValid()) {
        getResult = { };
        return;
    }

    if (m_info.cursorType() == IndexedDB::CursorType::KeyOnly)
        getResult = { m_currentKey, m_currentPrimaryKey };
    else {
        IDBValue value = { m_index.objectStore().valueForKey(m_currentPrimaryKey), { }, { } };
        getResult = { m_currentKey, m_currentPrimaryKey, WTFMove(value), m_index.objectStore().info().keyPath() };
    }
}

void MemoryIndexCursor::iterate(const IDBKeyData& key, const IDBKeyData& primaryKey, uint32_t count, IDBGetResult& getResult)
{
    LOG(IndexedDB, "MemoryIndexCursor::iterate to key %s, %u count", key.loggingString().utf8().data(), count);

#ifndef NDEBUG
    if (primaryKey.isValid())
        ASSERT(key.isValid());
#endif

    if (key.isValid()) {
        // Cannot iterate by both a count and to a key
        ASSERT(!count);

        auto* valueStore = m_index.valueStore();
        if (!valueStore) {
            m_currentKey = { };
            m_currentPrimaryKey = { };
            getResult = { };
            return;
        }

        if (primaryKey.isValid()) {
            if (m_info.isDirectionForward())
                m_currentIterator = valueStore->find(key, primaryKey);
            else
                m_currentIterator = valueStore->reverseFind(key, primaryKey, m_info.duplicity());
        } else {
            if (m_info.isDirectionForward())
                m_currentIterator = valueStore->find(key);
            else
                m_currentIterator = valueStore->reverseFind(key, m_info.duplicity());
        }

        if (m_currentIterator.isValid() && !m_info.range().containsKey(m_currentIterator.key()))
            m_currentIterator.invalidate();

        if (!m_currentIterator.isValid()) {
            m_currentKey = { };
            m_currentPrimaryKey = { };
            getResult = { };
            return;
        }

        m_index.cursorDidBecomeClean(*this);

        m_currentKey = m_currentIterator.key();
        m_currentPrimaryKey = m_currentIterator.primaryKey();
        currentData(getResult);

        return;
    }

    // If there was not a valid key argument and no positive count argument
    // that means the default iteration count of "1"
    if (!count)
        count = 1;

    if (!m_currentIterator.isValid()) {
        auto* valueStore = m_index.valueStore();
        if (!valueStore) {
            m_currentKey = { };
            m_currentPrimaryKey = { };
            getResult = { };
            return;
        }

        switch (m_info.cursorDirection()) {
        case IndexedDB::CursorDirection::Next:
            m_currentIterator = valueStore->find(m_currentKey, m_currentPrimaryKey);
            break;
        case IndexedDB::CursorDirection::Nextunique:
            m_currentIterator = valueStore->find(m_currentKey, true);
            break;
        case IndexedDB::CursorDirection::Prev:
            m_currentIterator = valueStore->reverseFind(m_currentKey, m_currentPrimaryKey, m_info.duplicity());
            break;
        case IndexedDB::CursorDirection::Prevunique:
            m_currentIterator = valueStore->reverseFind(m_currentKey, m_info.duplicity(), true);
            break;
        }

        if (!m_currentIterator.isValid()) {
            m_currentKey = { };
            m_currentPrimaryKey = { };
            getResult = { };
            return;
        }

        m_index.cursorDidBecomeClean(*this);

        // If we restored the current iterator and it does *not* match the current key/primaryKey,
        // then it is the next record in line and we should consider that an iteration.
        if (m_currentKey != m_currentIterator.key() || m_currentPrimaryKey != m_currentIterator.primaryKey())
            --count;
    }

    ASSERT(m_currentIterator.isValid());

    while (count) {
        if (m_info.duplicity() == CursorDuplicity::NoDuplicates)
            m_currentIterator.nextIndexEntry();
        else
            ++m_currentIterator;

        if (!m_currentIterator.isValid())
            break;

        --count;
    }

    if (m_currentIterator.isValid() && !m_info.range().containsKey(m_currentIterator.key()))
        m_currentIterator.invalidate();

    // Not having a valid iterator after finishing any iteration means we've reached the end of the cursor.
    if (!m_currentIterator.isValid()) {
        m_currentKey = { };
        m_currentPrimaryKey = { };
        getResult = { };
        return;
    }

    m_currentKey = m_currentIterator.key();
    m_currentPrimaryKey = m_currentIterator.primaryKey();
    currentData(getResult);
}

void MemoryIndexCursor::indexRecordsAllChanged()
{
    m_currentIterator.invalidate();
    m_index.cursorDidBecomeDirty(*this);
}

void MemoryIndexCursor::indexValueChanged(const IDBKeyData& key, const IDBKeyData& primaryKey)
{
    if (m_currentKey != key || m_currentPrimaryKey != primaryKey)
        return;

    m_currentIterator.invalidate();
    m_index.cursorDidBecomeDirty(*this);
}

} // namespace IDBServer
} // namespace WebCore

#endif // ENABLE(INDEXED_DATABASE)