FreeCAD/src/Base/Sequencer.h

406 lines
14 KiB
C++

/***************************************************************************
* Copyright (c) 2004 Werner Mayer <wmayer[at]users.sourceforge.net> *
* *
* This file is part of the FreeCAD CAx development system. *
* *
* This library is free software; you can redistribute it and/or *
* modify it under the terms of the GNU Library General Public *
* License as published by the Free Software Foundation; either *
* version 2 of the License, or (at your option) any later version. *
* *
* This library is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU Library General Public License for more details. *
* *
* You should have received a copy of the GNU Library General Public *
* License along with this library; see the file COPYING.LIB. If not, *
* write to the Free Software Foundation, Inc., 59 Temple Place, *
* Suite 330, Boston, MA 02111-1307, USA *
* *
***************************************************************************/
#ifndef BASE_SEQUENCER_H
#define BASE_SEQUENCER_H
#include <vector>
#include <memory>
#include <CXX/Extensions.hxx>
#include "Exception.h"
namespace Base
{
class AbortException;
class SequencerLauncher;
/**
* \brief This class gives the user an indication of the progress of an operation and
* it is used to reassure him that the application is still running.
*
* Here are some code snippets of how to use the sequencer:
* \code
*
* #include <Base/Sequencer.h>
*
* //first example
* Base::SequencerLauncher seq("my text", 10))
* for (int i=0; i<10; i++)
* {
* // do something
* seq.next ();
* }
*
* //second example
* Base::SequencerLauncher seq("my text", 10))
* do
* {
* // do something
* }
* while (seq.next());
*
* \endcode
*
* The implementation of this class also supports several nested instances
* at a time. But note, that only the first instance has an effect. Any further
* sequencer instance doesn't influence the total numer of iteration steps. This
* is simply because it's impossible to get the exact number of iteration steps
* for nested instances and thus we have either too few steps estimated then the
* sequencer may indicate 100% but the algorithm still running or we have too many
* steps estimated so that the an algorithm may stop long before the sequencer
* reaches 100%.
*
* \code
* try {
* //start the first operation
* Base::SequencerLauncher seq1("my text", 10)
* for (int i=0; i<10, i++)
* {
* // do something
*
* // start the second operation while the first one is still running
* Base::SequencerLauncher seq2("another text", 10);
* for (int j=0; j<10; j++)
* {
* // do something different
* seq2.next ();
* }
*
* seq1.next ( true ); // allow to cancel
* }
* }
* catch(const Base::AbortException&){
* // cleanup your data if needed
* }
*
* \endcode
*
* \note If using the sequencer with SequencerLauncher.next(\a true) then you must
* take into account that the exception \a AbortException could be thrown, e.g. in
* case the ESC button was pressed. So in this case it's always a good idea to use
* the sequencer within a try-catch block.
*
* \note Instances of SequencerLauncher should always be created on the stack.
* This is because if an exception somewhere is thrown the destructor is auto-
* matically called to clean-up internal data.
*
* \note It's not supported to create an instance of SequencerBase or a sub-class
* in another thread than the main thread. But you can create SequencerLauncher
* instances in other threads.
*
* \author Werner Mayer
*/
class BaseExport SequencerBase
{
friend class SequencerLauncher;
public:
/**
* Returns the last created sequencer instance.
* If you create an instance of a class inheriting SequencerBase
* this object is retrieved instead.
*
* This mechanism is very useful to have an own sequencer for each layer of FreeCAD.
* For example, if FreeCAD is running in server mode you have/need no GUI layer
* and therewith no (graphical) progress bar; in this case ConsoleSequencer is taken.
* But in cases FreeCAD is running with GUI the @ref Gui::ProgressBar is taken instead.
* @see Sequencer
*/
static SequencerBase& Instance();
/**
* Returns true if the running sequencer is blocking any user input.
* This might be only of interest of the GUI where the progress bar or dialog
* is used from a thread. If started from a thread this method should return
* false, otherwise true. The default implementation always returns true.
*/
virtual bool isBlocking() const;
/** If \a bLock is true then the sequencer gets locked. startStep() and nextStep()
* don't get invoked any more until the sequencer gets unlocked again.
* This method returns the previous lock state.
*/
bool setLocked(bool bLock);
/** Returns true if the sequencer was locked, false otherwise. */
bool isLocked() const;
/** Returns true if the sequencer is running, otherwise returns false. */
bool isRunning() const;
/**
* Returns true if the pending operation was canceled.
*/
bool wasCanceled() const;
protected:
/**
* Starts a new operation, returns false if there is already a pending operation,
* otherwise it returns true.
* In this method startStep() gets invoked that can be reimplemented in sub-classes.
*/
bool start(const char* pszStr, size_t steps);
/** Returns the number of steps. */
size_t numberOfSteps() const;
/** Returns the current state of progress in percent. */
int progressInPercent() const;
/**
* Performs the next step and returns true if the operation is not yet finished.
* But note, when 0 was passed to start() as the number of total steps this method
* always returns false.
*
* In this method nextStep() gets invoked that can be reimplemented in sub-classes.
* If \a canAbort is true then the operations can be aborted, otherwise (the default)
* the operation cannot be aborted. In case it gets aborted an exception AbortException
* is thrown.
*/
bool next(bool canAbort = false);
/**
* Stops the sequencer if all operations are finished. It returns false if
* there are still pending operations, otherwise it returns true.
*/
bool stop();
/**
* Breaks the sequencer if needed. The default implementation does nothing.
* Every pause() must eventually be followed by a corresponding @ref resume().
* @see Gui::ProgressBar.
*/
virtual void pause();
/**
* Continues with progress. The default implementation does nothing.
* @see pause(), @see Gui::ProgressBar.
*/
virtual void resume();
/**
* Try to cancel the pending operation(s).
* E.g. @ref Gui::ProgressBar calls this method after the ESC button was pressed.
*/
void tryToCancel();
/**
* If you tried to cancel but then decided to continue the operation.
* E.g. in @ref Gui::ProgressBar a dialog appears asking if you really want to
* cancel. If you decide to continue this method must be called.
*/
void rejectCancel();
protected:
/** construction */
SequencerBase();
/** Destruction */
virtual ~SequencerBase();
/**
* Sets a text what the pending operation is doing. The default implementation
* does nothing.
*/
virtual void setText (const char* pszTxt);
/**
* This method can be reimplemented in sub-classes to give the user a feedback
* when a new sequence starts. The default implementation does nothing.
*/
virtual void startStep();
/**
* This method can be reimplemented in sub-classes to give the user a feedback
* when the next is performed. The default implementation does nothing. If \a canAbort
* is true then the pending operation can aborted, otherwise not. Depending on the
* re-implementation this method can throw an AbortException if canAbort is true.
*/
virtual void nextStep(bool canAbort);
/**
* Sets the progress indicator to a certain position.
*/
virtual void setProgress(size_t);
/**
* Resets internal data.
* If you want to reimplement this method, it is very important to call it in
* the re-implemented method.
*/
virtual void resetData();
protected:
size_t nProgress; /**< Stores the current amount of progress.*/
size_t nTotalSteps; /**< Stores the total number of steps */
private:
bool _bLocked; /**< Lock/unlock sequencer. */
bool _bCanceled; /**< Is set to true if the last pending operation was canceled */
int _nLastPercentage; /**< Progress in percent. */
};
/** This special sequencer might be useful if you want to suppress any indication
* of the progress to the user.
*/
class BaseExport EmptySequencer : public Base::SequencerBase
{
public:
/** construction */
EmptySequencer();
/** Destruction */
~EmptySequencer();
};
/**
* \brief This class writes the progress to the console window.
*/
class BaseExport ConsoleSequencer : public SequencerBase
{
public:
/** construction */
ConsoleSequencer ();
/** Destruction */
~ConsoleSequencer ();
protected:
/** Starts the sequencer */
void startStep();
/** Writes the current progress to the console window. */
void nextStep(bool canAbort);
private:
/** Puts text to the console window */
void setText (const char* pszTxt);
/** Resets the sequencer */
void resetData();
};
/** The SequencerLauncher class is provided for convenience. It allows you to run an instance of the
* sequencer by instantiating an object of this class -- most suitable on the stack. So this mechanism
* can be used for try-catch-blocks to destroy the object automatically if the C++ exception mechanism
* cleans up the stack.
*
* This class has been introduced to simplify the use with the sequencer. In the FreeCAD Gui layer there
* is a subclass of SequencerBase called ProgressBar that grabs the keyboard and filters most of the incoming
* events. If the programmer uses the API of SequencerBase directly to start an instance without due diligence
* with exceptions then a not handled exception could block the whole application -- the user has to kill the
* application then.
*
* Below is an example of a not correctly used sequencer.
*
* \code
*
* #include <Base/Sequencer.h>
*
* void runOperation();
*
* void myTest()
* {
* try{
* runOperation();
* } catch(...) {
* // the programmer forgot to stop the sequencer here
* // Under circumstances the sequencer never gets stopped so the keyboard never gets ungrabbed and
* // all Gui events still gets filtered.
* }
* }
*
* void runOperation()
* {
* Base::Sequencer().start ("my text", 10);
*
* for (int i=0; i<10; i++)
* {
* // do something where an exception be thrown
* ...
* Base::Sequencer().next ();
* }
*
* Base::Sequencer().stop ();
* }
*
* \endcode
*
* To avoid such problems the SequencerLauncher class can be used as follows:
*
* \code
*
* #include <Base/Sequencer.h>
*
* void runOperation();
*
* void myTest()
* {
* try{
* runOperation();
* } catch(...) {
* // the programmer forgot to halt the sequencer here
* // If SequencerLauncher leaves its scope the object gets destructed automatically and
* // stops the running sequencer.
* }
* }
*
* void runOperation()
* {
* // create an instance on the stack (not on any terms on the heap)
* SequencerLauncher seq("my text", 10);
*
* for (int i=0; i<10; i++)
* {
* // do something (e.g. here can be thrown an exception)
* ...
* seq.next ();
* }
* }
*
* \endcode
*
* @author Werner Mayer
*/
class BaseExport SequencerLauncher
{
public:
SequencerLauncher(const char* pszStr, size_t steps);
~SequencerLauncher();
size_t numberOfSteps() const;
void setText (const char* pszTxt);
bool next(bool canAbort = false);
void setProgress(size_t);
bool wasCanceled() const;
};
/** Access to the only SequencerBase instance */
inline SequencerBase& Sequencer ()
{
return SequencerBase::Instance();
}
class BaseExport ProgressIndicatorPy : public Py::PythonExtension<ProgressIndicatorPy>
{
public:
static void init_type(void); // announce properties and methods
ProgressIndicatorPy();
~ProgressIndicatorPy();
Py::Object repr();
Py::Object start(const Py::Tuple&);
Py::Object next(const Py::Tuple&);
Py::Object stop(const Py::Tuple&);
private:
static PyObject *PyMake(struct _typeobject *, PyObject *, PyObject *);
private:
std::auto_ptr<SequencerLauncher> _seq;
};
} // namespace Base
#endif // BASE_SEQUENCER_H