QScriptEngineAgent Class

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Member Function Documentation

QScriptEngineAgent::QScriptEngineAgent(QScriptEngine *engine)

Constructs a QScriptEngineAgent object for the given engine.

The engine takes ownership of the agent.

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

[virtual] QScriptEngineAgent::~QScriptEngineAgent()

Destroys this QScriptEngineAgent.

[virtual] void QScriptEngineAgent::contextPop()

This function is called when the current script context is about to be popped.

The default implementation does nothing.

See also contextPush() and functionExit().

[virtual] void QScriptEngineAgent::contextPush()

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

The default implementation does nothing.

See also contextPop() and functionEntry().

QScriptEngine *QScriptEngineAgent::engine() const

Returns the QScriptEngine that this agent is associated with.

[virtual] void QScriptEngineAgent::exceptionCatch(qint64 scriptId, const QScriptValue &exception)

This function is called when the given exception is about to be caught, in the script identified by scriptId.

Reimplement this function if you want to handle this event.

The default implementation does nothing.

See also exceptionThrow().

[virtual] void QScriptEngineAgent::exceptionThrow(qint64 scriptId, const QScriptValue &exception, bool hasHandler)

This function is called when the given exception has occurred in the engine, in the script identified by scriptId. If the exception was thrown by a native Qt Script function, scriptId is -1.

If hasHandler is true, there is a catch or finally block that will handle the exception. If 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. hasHandler is false).

The default implementation does nothing.

See also exceptionCatch().

[virtual] QVariant QScriptEngineAgent::extension(QScriptEngineAgent::Extension extension, const QVariant &argument = QVariant())

This virtual function can be reimplemented in a QScriptEngineAgent subclass to provide support for extensions. The optional argument can be provided as input to the 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 debugger statement is encountered in a script. The 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).

See also supportsExtension().

[virtual] void QScriptEngineAgent::functionEntry(qint64 scriptId)

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 scriptId; otherwise, 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.

See also functionExit(), positionChange(), and QScriptEngine::currentContext().

[virtual] void QScriptEngineAgent::functionExit(qint64 scriptId, const QScriptValue &returnValue)

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 scriptId; otherwise, scriptId is -1. The 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 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.

See also functionEntry() and QScriptEngine::hasUncaughtException().

[virtual] void QScriptEngineAgent::positionChange(qint64 scriptId, int lineNumber, int columnNumber)

This function is called when the engine is about to execute a new statement in the script identified by scriptId. The statement begins on the line and column specified by lineNumber 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.

See also scriptLoad() and functionEntry().

[virtual] void QScriptEngineAgent::scriptLoad(qint64 id, const QString &program, const QString &fileName, int baseLineNumber)

This function is called when the engine has parsed a script and has associated it with the given id. The id can be used to identify this particular script in subsequent event notifications.

program, fileName and 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.

See also scriptUnload().

[virtual] void QScriptEngineAgent::scriptUnload(qint64 id)

This function is called when the engine has discarded the script identified by the given id.

You can reimplement this function to clean up any resources you have associated with the script.

The default implementation does nothing.

See also scriptLoad().

[virtual] bool QScriptEngineAgent::supportsExtension(QScriptEngineAgent::Extension extension) const

Returns true if the QScriptEngineAgent supports the given extension; otherwise, false is returned. By default, no extensions are supported.

See also extension().