loader/icon/IconDatabaseBase.h

/*
 * 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 COMPUTER, 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 COMPUTER, 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.
 */

#ifndef IconDatabaseBase_h
#define IconDatabaseBase_h

#include "SharedBuffer.h"

#include <wtf/Forward.h>
#include <wtf/Noncopyable.h>
#include <wtf/PassRefPtr.h>

namespace WebCore {

class DocumentLoader;
class IconDatabaseClient;
class Image;
class IntSize;

enum IconLoadDecision {
    IconLoadYes,
    IconLoadNo,
    IconLoadUnknown
};

class CallbackBase : public RefCounted<CallbackBase> {
public:
    virtual ~CallbackBase()
    {
    }

    uint64_t callbackID() const { return m_callbackID; }

protected:
    CallbackBase(void* context)
        : m_context(context)
        , m_callbackID(generateCallbackID())
    {
    }

    void* context() const { return m_context; }

private:
    static uint64_t generateCallbackID()
    {
        static uint64_t uniqueCallbackID = 1;
        return uniqueCallbackID++;
    }

    void* m_context;
    uint64_t m_callbackID;
};

template<typename EnumType>
class EnumCallback : public CallbackBase {
public:
    typedef void (*CallbackFunction)(EnumType, void*);

    static PassRefPtr<EnumCallback> create(void* context, CallbackFunction callback)
    {
        return adoptRef(new EnumCallback(context, callback));
    }

    virtual ~EnumCallback()
    {
        ASSERT(!m_callback);
    }

    void performCallback(EnumType result)
    {
        if (!m_callback)
            return;
        m_callback(result, context());
        m_callback = 0;
    }

    void invalidate()
    {
        m_callback = 0;
    }

private:
    EnumCallback(void* context, CallbackFunction callback)
        : CallbackBase(context)
        , m_callback(callback)
    {
        ASSERT(m_callback);
    }

    CallbackFunction m_callback;
};

template<typename ObjectType>
class ObjectCallback : public CallbackBase {
public:
    typedef void (*CallbackFunction)(ObjectType, void*);

    static PassRefPtr<ObjectCallback> create(void* context, CallbackFunction callback)
    {
        return adoptRef(new ObjectCallback(context, callback));
    }

    virtual ~ObjectCallback()
    {
        ASSERT(!m_callback);
    }

    void performCallback(ObjectType result)
    {
        if (!m_callback)
            return;
        m_callback(result, context());
        m_callback = 0;
    }

    void invalidate()
    {
        m_callback = 0;
    }

private:
    ObjectCallback(void* context, CallbackFunction callback)
        : CallbackBase(context)
        , m_callback(callback)
    {
        ASSERT(m_callback);
    }

    CallbackFunction m_callback;
};

typedef EnumCallback<IconLoadDecision> IconLoadDecisionCallback;
typedef ObjectCallback<SharedBuffer*> IconDataCallback;

class IconDatabaseBase {
    WTF_MAKE_NONCOPYABLE(IconDatabaseBase);

protected:
    IconDatabaseBase() { }

public:
    virtual ~IconDatabaseBase() { }

    // Used internally by WebCore
    virtual bool isEnabled() const { return false; }

    virtual void retainIconForPageURL(const String&) { }
    virtual void releaseIconForPageURL(const String&) { }

    virtual void setIconURLForPageURL(const String&, const String&) { }
    virtual void setIconDataForIconURL(PassRefPtr<SharedBuffer>, const String&) { }

    // Synchronous calls used internally by WebCore.
    // Usage should be replaced by asynchronous calls.
    virtual String synchronousIconURLForPageURL(const String&);
    virtual bool synchronousIconDataKnownForIconURL(const String&) { return false; }
    virtual IconLoadDecision synchronousLoadDecisionForIconURL(const String&, DocumentLoader*) { return IconLoadNo; }
    virtual Image* synchronousIconForPageURL(const String&, const IntSize&) { return 0; }

    // Asynchronous calls we should use to replace the above when supported.
    virtual bool supportsAsynchronousMode() { return false; }
    virtual void loadDecisionForIconURL(const String&, PassRefPtr<IconLoadDecisionCallback>) { }
    virtual void iconDataForIconURL(const String&, PassRefPtr<IconDataCallback>) { }


    // Used within one or more WebKit ports.
    // We should try to remove these dependencies from the IconDatabaseBase class.
    virtual void setEnabled(bool) { }

    virtual Image* defaultIcon(const IntSize&) { return 0; }

    virtual size_t pageURLMappingCount() { return 0; }
    virtual size_t retainedPageURLCount() { return 0; }
    virtual size_t iconRecordCount() { return 0; }
    virtual size_t iconRecordCountWithData() { return 0; }

    virtual void importIconURLForPageURL(const String&, const String&) { }
    virtual void importIconDataForIconURL(PassRefPtr<SharedBuffer>, const String&) { }
    virtual bool shouldStopThreadActivity() const { return true; }

    virtual bool open(const String& directory, const String& filename);
    virtual void close() { }
    virtual void removeAllIcons() { }

    virtual void setPrivateBrowsingEnabled(bool) { }
    virtual void setClient(IconDatabaseClient*) { }

    virtual bool isOpen() const { return false; }
    virtual String databasePath() const;

};

// Functions to get/set the global icon database.
IconDatabaseBase& iconDatabase();
void setGlobalIconDatabase(IconDatabaseBase*);

} // namespace WebCore

#endif // IconDatabaseBase_h