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** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the QtScript module of the Qt Toolkit.

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** $QT_BEGIN_LICENSE:LGPL-ONLY$

** GNU Lesser General Public License Usage

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#include "config.h"

#include "qscriptengineagent.h"

#include "qscriptengineagent_p.h"

#include "qscriptengine.h"

#include "qscriptengine_p.h"

#include "CodeBlock.h"

#include "Instruction.h"

QT_BEGIN_NAMESPACE

/*!

  \since 4.4

  \class QScriptEngineAgent

  \brief The QScriptEngineAgent class provides an interface to report events pertaining to QScriptEngine execution.

  \ingroup script

  The QScriptEngineAgent class is the basis of tools that monitor and/or control the execution of a

  QScriptEngine, such as debuggers and profilers.

  To process script loading and unloading events, reimplement the

  scriptLoad() and scriptUnload() functions. scriptLoad() is called

  after the input to QScriptEngine::evaluate() has been parsed, right

  before the given script is executed. The engine assigns each

  script an ID, which is available as one of the arguments to

  scriptLoad(); subsequently, other event handlers can use the ID to

  identify a particular script. One common usage of scriptLoad() is

  to retain the script text, filename and base line number (the

  original input to QScriptEngine::evaluate()), so that other event

  handlers can e.g. map a line number to the corresponding line of

  text.

  scriptUnload() is called when the QScriptEngine has no further use

  for a script; the QScriptEngineAgent may at this point safely

  discard any resources associated with the script (such as the

  script text). Note that after scriptUnload() has been called, the

  QScriptEngine may reuse the relevant script ID for new scripts

  (i.e. as argument to a subsequent call to scriptLoad()).

  Evaluating the following script will result in scriptUnload()

  being called immediately after evaluation has completed:

  \snippet doc/src/snippets/code/src_script_qscriptengineagent.cpp 0

  Evaluating the following script will \b{not} result in a call to

  scriptUnload() when evaluation has completed:

  \snippet doc/src/snippets/code/src_script_qscriptengineagent.cpp 1

  The script isn't unloaded because it defines a function (\c{cube})

  that remains in the script environment after evaluation has

  completed. If a subsequent script removed the \c{cube} function

  (e.g. by setting it to \c{null}), scriptUnload() would be called

  when the function is garbage collected. In general terms, a script

  isn't unloaded until the engine has determined that none of its

  contents is referenced.

  To process script function calls and returns, reimplement the

  functionEntry() and functionExit() functions. functionEntry() is

  called when a script function is about to be executed;

  functionExit() is called when a script function is about to return,

  either normally or due to an exception.

  To process individual script statements, reimplement

  positionChange(). positionChange() is called each time the engine is

  about to execute a new statement of a script, and thus offers the

  finest level of script monitoring.

  To process exceptions, reimplement exceptionThrow() and

  exceptionCatch(). exceptionThrow() is called when a script exception

  is thrown, before it has been handled. exceptionCatch() is called

  when an exception handler is present, and execution is about to be

  resumed at the handler code.

  \sa QScriptEngine::setAgent(), QScriptContextInfo

*/

/*!

  \enum QScriptEngineAgent::Extension

  This enum specifies the possible extensions to a QScriptEngineAgent.

  \value DebuggerInvocationRequest The agent handles \c{debugger} script statements.

  \sa extension()

*/

void QScriptEngineAgentPrivate::attach()

{

    if (engine->originalGlobalObject()->debugger())

        engine->originalGlobalObject()->setDebugger(0);

    JSC::Debugger::attach(engine->originalGlobalObject());

}

void QScriptEngineAgentPrivate::detach()

{

    JSC::Debugger::detach(engine->originalGlobalObject());

}

void QScriptEngineAgentPrivate::returnEvent(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, int lineno)

{

    Q_UNUSED(frame);

    Q_UNUSED(lineno);

    Q_UNUSED(sourceID);

}

void QScriptEngineAgentPrivate::exceptionThrow(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, bool hasHandler)

{

    JSC::CallFrame *oldFrame = engine->currentFrame;

    engine->currentFrame = frame.callFrame();

    QScriptValue value(engine->scriptValueFromJSCValue(frame.exception()));

    q_ptr->exceptionThrow(sourceID, value, hasHandler);

    engine->currentFrame = oldFrame;

    engine->setCurrentException(value);

};

void QScriptEngineAgentPrivate::exceptionCatch(const JSC::DebuggerCallFrame& frame, intptr_t sourceID)

{

    JSC::CallFrame *oldFrame = engine->currentFrame;

    engine->currentFrame = frame.callFrame();

    QScriptValue value(engine->scriptValueFromJSCValue(frame.exception()));

    q_ptr->exceptionCatch(sourceID, value);

    engine->currentFrame = oldFrame;

    engine->clearCurrentException();

}

void QScriptEngineAgentPrivate::atStatement(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, int lineno, int column)

{

    QScript::UStringSourceProviderWithFeedback *source = engine->loadedScripts.value(sourceID);

    if (!source) {

        // QTBUG-6108: We don't have the source for this script, so ignore.

        return;

    }

    column = source->columnNumberFromOffset(column);

    JSC::CallFrame *oldFrame = engine->currentFrame;

    int oldAgentLineNumber = engine->agentLineNumber;

    engine->currentFrame = frame.callFrame();

    engine->agentLineNumber = lineno;

    q_ptr->positionChange(sourceID, lineno, column);

    engine->currentFrame = oldFrame;

    engine->agentLineNumber = oldAgentLineNumber;

}

void QScriptEngineAgentPrivate::functionExit(const JSC::JSValue& returnValue, intptr_t sourceID)

{

    QScriptValue result = engine->scriptValueFromJSCValue(returnValue);

    q_ptr->functionExit(sourceID, result);

    q_ptr->contextPop();

}

void QScriptEngineAgentPrivate::evaluateStop(const JSC::JSValue& returnValue, intptr_t sourceID)

{

    QScriptValue result = engine->scriptValueFromJSCValue(returnValue);

    q_ptr->functionExit(sourceID, result);

}

void QScriptEngineAgentPrivate::didReachBreakpoint(const JSC::DebuggerCallFrame& frame,

                                                   intptr_t sourceID, int lineno, int column)

{

    if (q_ptr->supportsExtension(QScriptEngineAgent::DebuggerInvocationRequest)) {

        QScript::UStringSourceProviderWithFeedback *source = engine->loadedScripts.value(sourceID);

        if (!source) {

            // QTBUG-6108: We don't have the source for this script, so ignore.

            return;

        }

        column = source->columnNumberFromOffset(column);

        JSC::CallFrame *oldFrame = engine->currentFrame;

        int oldAgentLineNumber = engine->agentLineNumber;

        engine->currentFrame = frame.callFrame();

        engine->agentLineNumber = lineno;

        QList<QVariant> args;

        args << qint64(sourceID) << lineno << column;

        q_ptr->extension(QScriptEngineAgent::DebuggerInvocationRequest, args);

        engine->currentFrame = oldFrame;

        engine->agentLineNumber = oldAgentLineNumber;

    }

};

/*!

    Constructs a QScriptEngineAgent object for the given \a engine.

    The engine takes ownership of the agent.

    Call QScriptEngine::setAgent() to make this agent the active

    agent.

*/

QScriptEngineAgent::QScriptEngineAgent(QScriptEngine *engine)

        : d_ptr(new QScriptEngineAgentPrivate())

{

    d_ptr->q_ptr = this;

    d_ptr->engine = QScriptEnginePrivate::get(engine);

    d_ptr->engine->ownedAgents.append(this);

}

/*!

  \internal

*/

QScriptEngineAgent::QScriptEngineAgent(QScriptEngineAgentPrivate &dd, QScriptEngine *engine)

    : d_ptr(&dd)

{

    d_ptr->q_ptr = this;

    d_ptr->engine = QScriptEnginePrivate::get(engine);

}

/*!

  Destroys this QScriptEngineAgent.

*/

QScriptEngineAgent::~QScriptEngineAgent()

{

    d_ptr->engine->agentDeleted(this); //### TODO: Can this throw?

}

/*!

  This function is called when the engine has parsed a script and has

  associated it with the given \a id. The id can be used to identify

  this particular script in subsequent event notifications.

  \a program, \a fileName and \a baseLineNumber are the original

  arguments to the QScriptEngine::evaluate() call that triggered this

  event.

  This function is called just before the script is about to be

  evaluated.

  You can reimplement this function to record information about the

  script; for example, by retaining the script text, you can obtain

  the line of text corresponding to a line number in a subsequent

  call to positionChange().

  The default implementation does nothing.

  \sa scriptUnload()

*/

void QScriptEngineAgent::scriptLoad(qint64 id, const QString &program,

                                    const QString &fileName, int baseLineNumber)

{

    Q_UNUSED(id);

    Q_UNUSED(program);

    Q_UNUSED(fileName);

    Q_UNUSED(baseLineNumber);

}

/*!

  This function is called when the engine has discarded the script

  identified by the given \a id.

  You can reimplement this function to clean up any resources you have

  associated with the script.

  The default implementation does nothing.

  \sa scriptLoad()

*/

void QScriptEngineAgent::scriptUnload(qint64 id)

{

    Q_UNUSED(id);

}

/*!

  This function is called when a new script context has been pushed.

  The default implementation does nothing.

  \sa contextPop(), functionEntry()

*/

void QScriptEngineAgent::contextPush()

{

}

/*!

  This function is called when the current script context is about to

  be popped.

  The default implementation does nothing.

  \sa contextPush(), functionExit()

*/

void QScriptEngineAgent::contextPop()

{

}

/*!

  This function is called when a script function is called in the

  engine. If the script function is not a native Qt Script function,

  it resides in the script identified by \a scriptId; otherwise, \a

  scriptId is -1.

  This function is called just before execution of the script function

  begins.  You can obtain the QScriptContext associated with the

  function call with QScriptEngine::currentContext(). The arguments

  passed to the function are available.

  Reimplement this function to handle this event. For example, a

  debugger implementation could reimplement this function (and

  functionExit()) to keep track of the call stack and provide

  step-over functionality.

  The default implementation does nothing.

  \sa functionExit(), positionChange(), QScriptEngine::currentContext()

*/

void QScriptEngineAgent::functionEntry(qint64 scriptId)

{

    Q_UNUSED(scriptId);

}

/*!

  This function is called when the currently executing script function

  is about to return. If the script function is not a native Qt Script

  function, it resides in the script identified by \a scriptId;

  otherwise, \a scriptId is -1. The \a returnValue is the value that

  the script function will return.

  This function is called just before the script function returns.

  You can still access the QScriptContext associated with the

  script function call with QScriptEngine::currentContext().

  If the engine's

  \l{QScriptEngine::hasUncaughtException()}{hasUncaughtException}()

  function returns true, the script function is exiting due to an

  exception; otherwise, the script function is returning normally.

  Reimplement this function to handle this event; typically you will

  then also want to reimplement functionEntry().

  The default implementation does nothing.

  \sa functionEntry(), QScriptEngine::hasUncaughtException()

*/

void QScriptEngineAgent::functionExit(qint64 scriptId,

                                      const QScriptValue &returnValue)

{

    Q_UNUSED(scriptId);

    Q_UNUSED(returnValue);

}

/*!

  This function is called when the engine is about to execute a new

  statement in the script identified by \a scriptId.  The statement

  begins on the line and column specified by \a lineNumber and \a

  columnNumber.  This event is not generated for native Qt Script

  functions.

  Reimplement this function to handle this event. For example, a

  debugger implementation could reimplement this function to provide

  line-by-line stepping, and a profiler implementation could use it to

  count the number of times each statement is executed.

  The default implementation does nothing.

  \sa scriptLoad(), functionEntry()

*/

void QScriptEngineAgent::positionChange(qint64 scriptId,

                                        int lineNumber, int columnNumber)

{

    Q_UNUSED(scriptId);

    Q_UNUSED(lineNumber);

    Q_UNUSED(columnNumber);

}

/*!

  This function is called when the given \a exception has occurred in

  the engine, in the script identified by \a scriptId. If the

  exception was thrown by a native Qt Script function, \a scriptId is

  -1.

  If \a hasHandler is true, there is a \c{catch} or \c{finally} block

  that will handle the exception. If \a hasHandler is false, there is

  no handler for the exception.

  Reimplement this function if you want to handle this event. For

  example, a debugger can notify the user when an uncaught exception

  occurs (i.e. \a hasHandler is false).

  The default implementation does nothing.

  \sa exceptionCatch()

*/

void QScriptEngineAgent::exceptionThrow(qint64 scriptId,

                                        const QScriptValue &exception,

                                        bool hasHandler)

{

    Q_UNUSED(scriptId);

    Q_UNUSED(exception);

    Q_UNUSED(hasHandler);

}

/*!

  This function is called when the given \a exception is about to be

  caught, in the script identified by \a scriptId.

  Reimplement this function if you want to handle this event.

  The default implementation does nothing.

  \sa exceptionThrow()

*/

void QScriptEngineAgent::exceptionCatch(qint64 scriptId,

                                        const QScriptValue &exception)

{

    Q_UNUSED(scriptId);

    Q_UNUSED(exception);

}

#if 0

/*!

  This function is called when a property of the given \a object has

  been added, changed or removed.

  Reimplement this function if you want to handle this event.

  The default implementation does nothing.

*/

void QScriptEngineAgent::propertyChange(qint64 scriptId,

                                        const QScriptValue &object,

                                        const QString &propertyName,

                                        PropertyChange change)

{

    Q_UNUSED(scriptId);

    Q_UNUSED(object);

    Q_UNUSED(propertyName);

    Q_UNUSED(change);

}

#endif

/*!

  Returns true if the QScriptEngineAgent supports the given \a

  extension; otherwise, false is returned. By default, no extensions

  are supported.

  \sa extension()

*/

bool QScriptEngineAgent::supportsExtension(Extension extension) const

{

    Q_UNUSED(extension);

    return false;

}

/*!

  This virtual function can be reimplemented in a QScriptEngineAgent

  subclass to provide support for extensions. The optional \a argument

  can be provided as input to the \a extension; the result must be

  returned in the form of a QVariant. You can call supportsExtension()

  to check if an extension is supported by the QScriptEngineAgent.  By

  default, no extensions are supported, and this function returns an

  invalid QVariant.

  If you implement the DebuggerInvocationRequest extension, Qt Script

  will call this function when a \c{debugger} statement is encountered

  in a script. The \a argument is a QVariantList containing three

  items: The first item is the scriptId (a qint64), the second item is

  the line number (an int), and the third item is the column number

  (an int).

  \sa supportsExtension()

*/

QVariant QScriptEngineAgent::extension(Extension extension,

                                       const QVariant &argument)

{

    Q_UNUSED(extension);

    Q_UNUSED(argument);

    return QVariant();

}

/*!

  Returns the QScriptEngine that this agent is associated with.

*/

QScriptEngine *QScriptEngineAgent::engine() const

{

    Q_D(const QScriptEngineAgent);

    return QScriptEnginePrivate::get(d->engine);

}

QT_END_NAMESPACE