cvs.zerfleddert.de Git - micropolis/blob - src/tk/tkatom.c

   1 /*
   2  * tkAtom.c --
   3  *
   4  *      This file manages a cache of X Atoms in order to avoid
   5  *      interactions with the X server.  It's much like the Xmu
   6  *      routines, except it has a cleaner interface (caller
   7  *      doesn't have to provide permanent storage for atom names,
   8  *      for example).
   9  *
  10  * Copyright 1990 Regents of the University of California.
  11  * Permission to use, copy, modify, and distribute this
  12  * software and its documentation for any purpose and without
  13  * fee is hereby granted, provided that the above copyright
  14  * notice appear in all copies.  The University of California
  15  * makes no representations about the suitability of this
  16  * software for any purpose.  It is provided "as is" without
  17  * express or implied warranty.
  18  */
  19
  20 #ifndef lint
  21 static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkAtom.c,v 1.6 92/05/07 09:51:06 ouster Exp $ SPRITE (Berkeley)";
  22 #endif
  23
  24 #include "tkconfig.h"
  25 #include "tkint.h"
  26
  27 /*
  28  * Forward references to procedures defined in this file:
  29  */
  30
  31 static void     AtomInit _ANSI_ARGS_((TkDisplay *dispPtr));
  32 \f
  33 /*
  34  *--------------------------------------------------------------
  35  *
  36  * Tk_InternAtom --
  37  *
  38  *      Given a string, produce the equivalent X atom.  This
  39  *      procedure is equivalent to XInternAtom, except that it
  40  *      keeps a local cache of atoms.  Once a name is known,
  41  *      the server need not be contacted again for that name.
  42  *
  43  * Results:
  44  *      The return value is the Atom corresponding to name.
  45  *
  46  * Side effects:
  47  *      A new entry may be added to the local atom cache.
  48  *
  49  *--------------------------------------------------------------
  50  */
  51
  52 Atom
  53 Tk_InternAtom (
  54     Tk_Window tkwin,            /* Window token;  map name to atom
  55                                  * for this window's display. */
  56     char *name                  /* Name to turn into atom. */
  57 )
  58 {
  59     register TkDisplay *dispPtr;
  60     register Tcl_HashEntry *hPtr;
  61     int new;
  62
  63     dispPtr = ((TkWindow *) tkwin)->dispPtr;
  64     if (!dispPtr->atomInit) {
  65         AtomInit(dispPtr);
  66     }
  67
  68     hPtr = Tcl_CreateHashEntry(&dispPtr->nameTable, name, &new);
  69     if (new) {
  70         Tcl_HashEntry *hPtr2;
  71         Atom atom;
  72
  73         atom = XInternAtom(dispPtr->display, name, False);
  74         Tcl_SetHashValue(hPtr, atom);
  75         hPtr2 = Tcl_CreateHashEntry(&dispPtr->atomTable, (char *) atom,
  76                 &new);
  77         Tcl_SetHashValue(hPtr2, Tcl_GetHashKey(&dispPtr->nameTable, hPtr));
  78     }
  79     return (Atom) Tcl_GetHashValue(hPtr);
  80 }
  81 \f
  82 /*
  83  *--------------------------------------------------------------
  84  *
  85  * Tk_GetAtomName --
  86  *
  87  *      This procedure is equivalent to XGetAtomName except that
  88  *      it uses the local atom cache to avoid contacting the
  89  *      server.
  90  *
  91  * Results:
  92  *      The return value is a character string corresponding to
  93  *      the atom given by "atom".  This string's storage space
  94  *      is static:  it need not be freed by the caller, and should
  95  *      not be modified by the caller.  If "atom" doesn't exist
  96  *      on tkwin's display, then the string "?bad atom?" is returned.
  97  *
  98  * Side effects:
  99  *      None.
 100  *
 101  *--------------------------------------------------------------
 102  */
 103
 104 char *
 105 Tk_GetAtomName (
 106     Tk_Window tkwin,            /* Window token;  map atom to name
 107                                  * relative to this window's
 108                                  * display. */
 109     Atom atom                   /* Atom whose name is wanted. */
 110 )
 111 {
 112     register TkDisplay *dispPtr;
 113     register Tcl_HashEntry *hPtr;
 114
 115     dispPtr = ((TkWindow *) tkwin)->dispPtr;
 116     if (!dispPtr->atomInit) {
 117         AtomInit(dispPtr);
 118     }
 119
 120     hPtr = Tcl_FindHashEntry(&dispPtr->atomTable, (char *) atom);
 121     if (hPtr == NULL) {
 122         char *name;
 123         Tk_ErrorHandler handler;
 124         int new;
 125
 126         handler= Tk_CreateErrorHandler(dispPtr->display, BadAtom,
 127                 -1, -1, (int (*)(int *, XErrorEvent *)) NULL, (ClientData) NULL);
 128         name = XGetAtomName(dispPtr->display, atom);
 129         if (name == NULL) {
 130             name = "?bad atom?";
 131         }
 132         Tk_DeleteErrorHandler(handler);
 133         hPtr = Tcl_CreateHashEntry(&dispPtr->nameTable, (char *) name,
 134                 &new);
 135         Tcl_SetHashValue(hPtr, atom);
 136         name = Tcl_GetHashKey(&dispPtr->nameTable, hPtr);
 137         hPtr = Tcl_CreateHashEntry(&dispPtr->atomTable, (char *) atom,
 138                 &new);
 139         Tcl_SetHashValue(hPtr, name);
 140     }
 141     return (char *) Tcl_GetHashValue(hPtr);
 142 }
 143 \f
 144 /*
 145  *--------------------------------------------------------------
 146  *
 147  * AtomInit --
 148  *
 149  *      Initialize atom-related information for a display.
 150  *
 151  * Results:
 152  *      None.
 153  *
 154  * Side effects:
 155  *      Tables get initialized, etc. etc..
 156  *
 157  *--------------------------------------------------------------
 158  */
 159
 160 static void
 161 AtomInit (
 162     register TkDisplay *dispPtr /* Display to initialize. */
 163 )
 164 {
 165     dispPtr->atomInit = 1;
 166     Tcl_InitHashTable(&dispPtr->nameTable, TCL_STRING_KEYS);
 167     Tcl_InitHashTable(&dispPtr->atomTable, TCL_ONE_WORD_KEYS);
 168 }