/*

 * Copyright (C) 2010 Google, 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. 

 */

#ifndef HTMLScriptRunner_h

#define HTMLScriptRunner_h

#include "CachedResourceClient.h"

#include "CachedResourceHandle.h"

#include <wtf/Noncopyable.h>

#include <wtf/PassRefPtr.h>

namespace WebCore {

class CachedResourceClient;

class CachedScript;

class Document;

class Element;

class Frame;

class HTMLScriptRunnerHost;

class ScriptSourceCode;

class HTMLScriptRunner : public Noncopyable {

public:

    HTMLScriptRunner(Document*, HTMLScriptRunnerHost*);

    ~HTMLScriptRunner();

    // Processes the passed in script and any pending scripts if possible.

    bool execute(PassRefPtr<Element> scriptToProcess, int scriptStartLine);

    bool executeScriptsWaitingForLoad(CachedResource*);

    bool hasScriptsWaitingForStylesheets() const { return m_hasScriptsWaitingForStylesheets; }

    bool executeScriptsWaitingForStylesheets();

    bool inScriptExecution() { return !!m_scriptNestingLevel; }

private:

    // A container for an external script which may be loaded and executed.

    //

    // A CachedResourceHandle alone does not prevent the underlying CachedResource

    // from purging its data buffer. This class holds a dummy client open for its

    // lifetime in order to guarantee that the data buffer will not be purged.

    //

    // FIXME: Finish turning this into a proper class.

    class PendingScript : public CachedResourceClient, Noncopyable {

    public:

        PendingScript()

            : startingLineNumber(0)

            , m_watchingForLoad(false)

        {

        }

        ~PendingScript();

        PassRefPtr<Element> releaseElementAndClear();

        bool watchingForLoad() const { return m_watchingForLoad; }

        void setWatchingForLoad(bool b) { m_watchingForLoad = b; }

        CachedScript* cachedScript() const;

        void setCachedScript(CachedScript*);

        virtual void notifyFinished(CachedResource*)

        {

        }

        RefPtr<Element> element;

        int startingLineNumber; // Only used for inline script tags.

        // HTML5 has an isReady parameter, however isReady ends up equivalent to

        // m_document->haveStylesheetsLoaded() && cachedScript->isLoaded()

    private:

        bool m_watchingForLoad;

        CachedResourceHandle<CachedScript> m_cachedScript;

    };

    Frame* frame() const;

    bool haveParsingBlockingScript() const;

    bool executeParsingBlockingScripts();

    void executePendingScript();

    void requestScript(Element*);

    void runScript(Element*, int startingLineNumber);

    // Helpers for dealing with HTMLScriptRunnerHost

    void watchForLoad(PendingScript&);

    void stopWatchingForLoad(PendingScript&);

    void executeScript(Element*, const ScriptSourceCode&);

    bool isPendingScriptReady(const PendingScript&);

    ScriptSourceCode sourceFromPendingScript(const PendingScript&, bool& errorOccurred);

    Document* m_document;

    HTMLScriptRunnerHost* m_host;

    PendingScript m_parsingBlockingScript;

    unsigned m_scriptNestingLevel;

    // We only want stylesheet loads to trigger script execution if script

    // execution is currently stopped due to stylesheet loads, otherwise we'd

    // cause nested script execution when parsing <style> tags since </style>

    // tags can cause Document to call executeScriptsWaitingForStylesheets.

    bool m_hasScriptsWaitingForStylesheets;

};

}

#endif