Paul Kingston

Paul Kingston

CS 91.592 Spring 2002

Final Report (02s592 Project)

Abstract: This report gives a brief overview of the contributions made to bde this semester. The following is a list of high-level tasks undertaken:

· Evaluation of platform-independent GUI toolkits.

· Prototype demonstration using the FOX GUI toolkit.

· Demonstration and addition of various Xt callback functions.

· Testing of bde remotely via X server software.

· Evaluation of named pipes for use in bde.

Details: The following explains each of the above bulleted items in greater detail.

Evaluation of platform-independent GUI toolkits (PIGUIs):

At the beginning of the semester some bde porting issues were discussed. Particularly the desire to make bde a cross-platform application. That is, to satisfy the widest range of users, it is desirable for bde to be able to be built and run on a variety of platforms. Several ports of bde already exist including a Windows version and a Java version. However these ports are not as well maintained as the flagship OSF-UNIX version of bde. In an effort to develop a single bde source tree which can be more easily built for a variety of platforms, it was determined that bde could benefit from a platform-independent toolkit from which to code the user interface. With the UI written with such a toolkit, bde could take the first large steps toward the goal of a single source tree supporting multiple platforms.

First a variety of online sources were consulted to assemble a master list of available PIGUIs. Next the list was filtered based on several factors, including number of platforms supported, licensing and support availability. The toolkits in the filtered list were then evaluated individually. This list is included in this report as Appendix A.

Prototype demonstration using the FOX GUI toolkit:

The recommendation after the above-outlined evaluation was to use the FOX toolkit (http://www.fox-toolkit.org/fox.html). A prototype bde GUI was then composed to demonstrate feasibility. The source code file, MyFOXApp.cpp is located in the following directory:

/usr/proj3/case/02s592/pkingsto/bde/extra/FOX

After presenting the prototype it was determined that the focus for the semester should be on other bde tasks, and so the PIGUI porting effort was abandoned.

Demonstration and addition of various Xt callback functions:

Introducing replay functionality into bde necessitated the need for new Xt callback functions which would initiate the stepping through the replay log. There were three Xt callback functions which were good candidates for providing this functionality: XtAppAddInput(), XtAppAddTimeOut() and XtAppAddWorkProc(). A brief description of these function is given here:

XtAppAddInput: The procedure passed as an argument is executed when the contents of the specified file change. Note that for use with bde, the file specified was <sdtin>, meaning that the passed procedure would execute whenever the <enter> key was pressed.

XtAppAddTimeOut: The procedure passed as an argument is executed after the specified time period has elapsed.

XtAppAddWorkProc: The procedure passed as an argument is executed when there are no other events in the application’s event queue.

Proof of concept programs were written for each of the three functions listed above. The source code for these programs is located in the following directory:

/usr/proj3/case/02s592/pkingsto/bde/extra/callbacks

These functions were then customized for use with bde. Their definitions reside in the bde source code file init.cc. Because it makes no sense to have more than one of these active at any one time, so it was determined that the XtAppAddTimeOut() function should be active by default. The remaining two callback functions are listed in init.cc but are commented out.

Listing of code additions for these Xt callback functions is given in Appendix B, build logs are given in Appendix C and testing information is given in Appendix D.

Testing of bde remotely via X server software:

In a distributed-bde system there will be users accessing bde from a variety of platforms and locations. Determining the processing load the current version of bde introduces when accessed remotely is important when designing future distributed versions. The current version of bde was tested remotely over a cable modem connection using Windows X server software. Test runs were tried at varying times of day from 6AM to 2AM. The results were dramatic – the response time of the system running bde was far too slow to be usable.

Evaluation of named pipes for use in bde:

It was proposed that client applications, rather than writing to a log file, could instead directly send replay messages to bde via an inter-process communication mechanism such as a named pipe. A pair of demonstration programs were found which demonstrate the use of a named pipe (called FIFOs in UNIX). These demonstration programs are located in the following directory:

/usr/proj3/case/02s592/pkingsto/bde/extra/fifo

Appendix A: Report Submitted on PIGUIs

Evaluation of OpenGL Cross-Platform GUI Toolkits

Of the 100 or so OpenGL cross-platform windowing toolkits listed on the OpenGL web page:

http://www.opengl.org/users/apps.hardware/applications/devtools.html

the following four appear to be the most promising. I have summed up the features of each below:

· GLT http://www.nigels.com/glt/

Type of toolkit: C++ interface to GLUT with extra features

Platforms supported: Same as GLUT - Win32, X11

Pros: Has a menu class

Cons: Should be considered an Alpha release

Support: Mailing list

License: GNU LGPL

· GLUI http://www.cs.unc.edu/~rademach/glui/

Type of toolkit: C++ wrapper for GLUT with extra features

Platforms supported: Same as GLUT - Win32, X11

Pros: Very rich set of widgets, Support for multiple user interface windows

Cons: No additional menu support

Support: Single email address

License: GNU LGPL

· FLTK (Fast Lightweight Toolkit) http://www.fltk.org/

Type of toolkit: C++ GUI toolkit with OpenGL

Platforms supported: Same as GLUT - Win32, X11 and MacOS

Pros: Has a UI builder called "FLUID", menu support

Cons: Not sure about multiple windows and external events

Support: Newsgroups

License: GNU PL

· FOX http://www.fox-toolkit.org/fox.html

Type of toolkit: C++ interface to OpenGL

Platforms supported: Same as GLUT - Win32, X11 and most UNIX flavors were mentioned

Pros: Support for external events, multiple windows

Cons: Not sure if there are any

Support: Mailing list with archives

License: GNU LGPL

Recommendation:

Of the four above, the last candidate, "FOX" appears to be the best choice. A large number of platforms are supported and external events and multiple windows are supported. The “FLTK” toolkit appears to be likewise promising. I would recommend that both these toolkits be evaluated further to see if they can be employed in bde development.

Appendix B: Code Additions for Xt Callbacks

The following is the output of a diff command showing the code additions made to init.cc and fileio.cc to implement the Xt callback functions.

init.cc

saturn.cs.uml.edu> diff ./init.cc ~lechner/bde2alpha_rl/sandbox/bde/src/init.cc

185,186d184

< #include <stdio.h>

< #include <stdlib.h>

190,191d187

< #include <Xm/Xm.h>

< #include <Xm/Label.h>

205,207d200

< ///////////////// Constants ////////////////////////////////////////

< #define XTAPPADDTIMEOUT_INTERVAL 5000

227c220

< extern void ReplayFunc();

---

246,251d238

< static void TimerFunc ( XtPointer clientData, XtIntervalId *id );

< static void InputFunc ( XtPointer clientData, int *fid, XtInputId *id );

< static Boolean WorkProcFunc ( XtPointer clientData );

517,525c504

< ////////////////////////Replay callbacks////////////////////////

< TimerFunc( ( XtPointer) canvas, NULL );

< /* Other X11 callbacks - uncomment as needed

< XtAppAddWorkProc( app, WorkProcFunc, canvas );

< XtAppAddInput( app, fileno ( stdin ), (XtPointer)XtInputReadMask,

< InputFunc, canvas );

< */

---

623,702d601

< /******************************************************

< * Function: ReplayFunc

< *

< * Description: Calls the replay_log() function.

< ******************************************************

< void ReplayFunc()

< {

< if(ReplayReady == 1)

< {

< if( replay_log() == STATE2 )

< ReplayReady = 0;

< }

< */

< /******************************************************

< * Function: TimerFunc

< *

< * Description: Calls ReplayFunc() repeatedly at a time interval

< * specified by the constant XTAPPADDTIMEOUT_INTERVAL.

< ******************************************************/

< static void TimerFunc( XtPointer clientData, XtIntervalId *id )

< {

< Widget w = (Widget)clientData;

< /* call ReplayFunc */

< ReplayFunc();

< /* re-register this timeout function to be called again */

< XtAppAddTimeOut ( XtWidgetToApplicationContext ( w ),

< XTAPPADDTIMEOUT_INTERVAL,

< TimerFunc, ( XtPointer ) w );

< }

< /******************************************************

< * Function: WorkProcFunc

< *

< * Description: Calls ReplayFunc() repeatedly when the system is idle.

< ******************************************************/

< static Boolean WorkProcFunc ( XtPointer clientData )

< {

< Widget w = (Widget)clientData;

< /* call ReplayFunc */

< ReplayFunc();

< if(ReplayReady == 1)

< return (FALSE); /* return FALSE if there's still work to do */

< else

< return (TRUE);

< }

< /******************************************************

< * Function: InputFunc

< *

< * Description: Calls ReplayFunc() whenever the <Return> key is pressed

< ******************************************************/

< static void InputFunc( XtPointer clientData, int *fid, XtInputId *id )

< {

< char buf[1024];

< Widget w = (Widget)clientData;

< /* call ReplayFunc */

< ReplayFunc();

< /* clean out the stdin buffer */

< /* fread( buf, sizeof(char), 1024, *fid ); */

< /* read(*fid, buf, 1024); */

< char ch;

< for (;;)

< {

< ch = getchar();

< if(ch == EOF)

< break;

< }

fileio.cc:

saturn.cs.uml.edu> diff ./fileio.cc ~lechner/bde2alpha_rl/sandbox/bde/src/fileio.cc

559c559

< void ReplayFunc();

---

2230,2242c2230

< /**************************************************************************

< * Function : ReplayFunc

< *

< * Description: Calls the replay_log() function.

< **************************************************************************/

< void ReplayFunc()

< {

< if(ReplayReady == 1)

< {

< if( replay_log() == STATE2 )

< ReplayReady = 0;

< }

---

Appendix C: Build Log

To build bde successfully, the following steps can be taken:

1) Copy entire source tree from ~lechner/bde2alpha_rl/sandbox/bde to a local directory:

saturn.cs.uml.edu> cp –R ~lechner/bde2alpha_rl/sandbox/bde .

2) Edit source files to include the code changes listed in Appendix B.

3) From your local bde directory, run make:

saturn.cs.uml.edu> make

The build procedure should show the following output:

saturn.cs.uml.edu> make

making all in ./pr_util...

making all in ./src...

g++ -c -DDEBUG -DString_REDEFINE_NOT_NEEDED -DBDE_SCHEMA="96subde_schema.h" -DBDE_VIEW="94sbdeview" -DS94LC -DLCWC -DDEFAULT_LIB_PATH=\"../lib\" -DBDELOG -g -Wall -I/usr/include -I../include -I../pr_util -I/usr/local/lib/g++-include bendpt.cc

bendpt.cc:143: warning: `char rcsid[59]' defined but not used