Program Listing Of Motif Version Of xviewfile

/* Motif Toolkit rendition of xviewfile */
/* An application to view the contents of a text file */
/* Jeff Pitchers, LUT 5/7/93 */

#include <stdio.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/stat.h>

/* Include the necessary Motif Toolkit header files */
#include <Xm/Xm.h>
#include <Xm/MainW.h>
#include <Xm/RowColumn.h>
#include <Xm/CascadeB.h>
#include <Xm/PushB.h>
#include <Xm/FileSB.h>
#include <Xm/MessageB.h>
#include <Xm/Text.h>

/* Define an application context */
XtAppContext ac;

/* Define the widgets */
Widget top, mainBox, fileText, menuBar, fileButton, fileMenu, openItem,
            helpButton, quitItem, fileDialog, quitDialog, errorDialog,
            helpDialog, temp;

/* Declare the callback functions */
int Open(), OpenFile(), Cancel(), Quit(), Ok(), Help();

XmString help;

main(argc, argv)
int argc; char **argv;
{
  /* Create the application shell widget */
  top = XtVaAppInitialize(&ac, "XViewfile", NULL, 0,& argc, argv, NULL, NULL);

  /* Create a box to hold everything */
  mainBox = XtVaCreateManagedWidget("mainBox", xmMainWindowWidgetClass,
            top, NULL);

  /* Create a menu bar within the box */
  menuBar = XmCreateMenuBar(mainBox, "menuBar", NULL, 0);
  XtManageChild(menuBar);

  /* Create a file menu, with open & quit selections */
  fileMenu = XmCreatePulldownMenu(menuBar, "fileMenu", NULL, 0);
  openItem = XtVaCreateManagedWidget("Open", xmPushButtonWidgetClass,
             fileMenu, NULL);
  quitItem = XtVaCreateManagedWidget("Quit", xmPushButtonWidgetClass,
             fileMenu, NULL);

  /* Create a file button which pops up the file menu */
  fileButton = XtVaCreateManagedWidget("File", xmCascadeButtonWidgetClass,
               menuBar,
               XmNsubMenuId, fileMenu,
               NULL);

  /* Create a popup dialog to get the filename; no help button */
  fileDialog = XmCreateFileSelectionDialog(mainBox, "fileDialog", NULL, 0);
  XtVaSetValues(fileDialog, XmNwidth, 400, NULL);
  temp = XmFileSelectionBoxGetChild(fileDialog, XmDIALOG_HELP_BUTTON);
  XtUnmanageChild(temp);

  /* Create a popup error message dialog; no cancel, no help button */
  errorDialog = XmCreateErrorDialog(mainBox, "errorDialog", NULL, 0);
  temp = XmMessageBoxGetChild(errorDialog, XmDIALOG_CANCEL_BUTTON);
  XtUnmanageChild(temp);
  temp = XmMessageBoxGetChild(errorDialog, XmDIALOG_HELP_BUTTON);
  XtUnmanageChild(temp);

  /* Create a read only, scrollable text widget, to display the file */
  fileText = XmCreateScrolledText(mainBox, "fileText", 0, NULL);
  XtVaSetValues(fileText,
                XmNeditMode, XmMULTI_LINE_EDIT,
                XmNeditable, 0,
                XmNrows, 24,
                XmNcolumns, 80,
                NULL);
  XtManageChild(fileText);

  /* Create a popup question dialog to confirm quit; no help button */
  quitDialog = XmCreateQuestionDialog(mainBox, "quitDialog", NULL, 0);
  temp = XmMessageBoxGetChild(quitDialog, XmDIALOG_HELP_BUTTON);
  XtUnmanageChild(temp);

  /* Create a help button & dialog for application; no cancel, no help button */
  helpButton = XtVaCreateManagedWidget("Help", xmCascadeButtonWidgetClass,
               menuBar, NULL);
  helpDialog = XmCreateInformationDialog(helpButton, "helpDialog", NULL, 0);
  temp = XmMessageBoxGetChild(helpDialog, XmDIALOG_HELP_BUTTON);
  XtUnmanageChild(temp);
  temp = XmMessageBoxGetChild(helpDialog, XmDIALOG_CANCEL_BUTTON);
  XtUnmanageChild(temp);

  /* Put the help text in to the help dialog */
  help = XmStringCreateSimple("To open a file, choose open from the file menu");
  XtVaSetValues(helpDialog, XmNmessageString, help, NULL);
  XmStringFree(help);

  /* Inform menuBar that this is the help button, so that it */
  /* can be positioned in the usual place for help buttons */
  XtVaSetValues(menuBar, XmNmenuHelpWidget, helpButton, NULL);

  /* Tie in the callbacks */
  XtAddCallback(openItem, XmNactivateCallback, Open, NULL);
  XtAddCallback(fileDialog, XmNokCallback, OpenFile, NULL);
  XtAddCallback(fileDialog, XmNcancelCallback, Cancel, NULL);
  XtAddCallback(quitItem, XmNactivateCallback, Quit, NULL);
  XtAddCallback(quitDialog, XmNokCallback, Ok, NULL);
  XtAddCallback(helpButton, XmNactivateCallback, Help, helpDialog, NULL);

  XtRealizeWidget(top);
  XtAppMainLoop(ac);
}

/* Callback routine when open menu item is selected from the file menu */
/* ARGSUSED */
Open(w, a, b)
Widget w; XtPointer a, b;
{
  XtManageChild(fileDialog);
}

/* Callback routine when OK is clicked in the file dialog */
/* ARGSUSED */
OpenFile(w, a, b)
Widget w; XtPointer a, b;
{
  FILE *fp, *fopen();
  struct stat stat_buf;
  off_t file_size;
  char *filename, *file_buf;
  XmString filename_sel_text, err_mess;

  /* Put the name of the file to be viewed in to the variable filename */
  XtVaGetValues(fileDialog, XmNtextString, &filename_sel_text, NULL);
  XmStringGetLtoR(filename_sel_text, XmSTRING_DEFAULT_CHARSET, &filename);
  XmStringFree(filename_sel_text);

  if ((fp = fopen(filename, "ro")) == NULL) { /* Oh oh, can't read that one */
    err_mess = XmStringCreateSimple("Can't open that file");
    XtVaSetValues(errorDialog, XmNmessageString, err_mess, NULL);
    XmStringFree(err_mess);
    XtManageChild(errorDialog);
  }
  else { /* Ok, read it */
    fstat(fileno(fp), &stat_buf);
    file_size = stat_buf.st_size;
    file_buf = malloc(file_size * sizeof(char) + 1);
    fread(file_buf, 1, file_size, fp);
    file_buf[file_size] = '\0';
    XmTextSetString(fileText, file_buf);
    free(file_buf);
    fclose(fp);
    XtUnmanageChild(fileDialog);
  }
  free(filename);
}

/* CallBack routine when cancel is clicked in the file dialog */
/* ARGSUSED */
Cancel(w, a, b)
Widget w; XtPointer a, b;
{
  XtUnmanageChild(fileDialog);
}

/* Callback routine when quit menu item is selected from the file menu */
/* ARGSUSED */
Quit(w, a, b)
Widget w; XtPointer a, b;
{
  XmString quitmess;

  quitmess = XmStringCreateSimple("Are you sure you want to quit?");
  XtVaSetValues(quitDialog, XmNmessageString, quitmess, NULL);
  XtManageChild(quitDialog);
}

/* Callback routine when OK is clicked in the quit dialog */ 
/* ARGSUSED */
Ok(w, a, b)
Widget w; XtPointer a, b;
{
  exit(0);
}

/* Callback routine to display help dialog when help button is clicked */
/* ARGSUSED */
Help(w, client_data, call_data)
Widget w;
XtPointer  client_data, call_data;
{
  XtManageChild(client_data);
}

 
Figure 22: The Motif version of xviewfile