john13@garfield.UUCP (05/03/87)
Here are the diffs to make MenuText and Restore more friendly - they will
try to detect if someone else is using UserData, and will abort as gracefully
as possible if so, with a warning not to tamper with these menus again.
Note 1: If a program does strange things to menus, creating them from arbitrary
data or something, don't try to change it. (This is only common sense)
Note 2: With all the emphasis on shared libraries, device drivers, files, etc
there really should be at least *1* shared access pointer in a window
structure. This is, of course, only my personal opinion.
Note 3: You can install the diffs (under Unix) like so:
cat diffs_1 | patch menutext.c
cat diffs_2 | patch restore.c
There is a program somewhere to do this via Edit on the Amiga itself, but I
don't know its name or where you would find it.
John
-----------------
diffs_1 - MenuText.c:
222a
if (ptr->key != MENU_KEY)
return(ABORT); /* someone else has altered UserData; abort */
.
212c
struct node *findnode(window,item) /* does item already have related node? */
.
176a
goto quit; /* only alter 1 window */
.
154c
(item->Flags & COMMSEQ ? COMMWIDTH+4 : 0);
.
130a
node->key = MENU_KEY; /* create tag value */
.
127a
if ( (node = findnode(window,item)) == ABORT) {
puts("Window structure not suitable for this program.");
goto quit;
}
/* is this the first alteration of this menuitem? */
if (node == NULL) {
.
126c
/* test that no other program has set UserData */
.
33a
short key; /* indicates valid node if key == 0x1234 */
.
20a
/* define a value which will indicate a valid node */
#define MENU_KEY 0x1234
/* define error code other than NULL for immediate exit */
#define ABORT 1
.
------------
diffs_2 - Restore.c:
88a
goto quit; /* only 1 window affected */
.
76a
/*
* De-allocate the nodes created by MENUTEXT. The program will exit with
* an error message if an invalid node (one without the proper key) is
* found while scanning the list, and attempt to repair any damage by
* pointing the window's UserData there (as that may be the original
* UserData value). This should never occur, since new menuitems will
* never be added to a window with an "altered" UserData, but you never
* know...
*
*
*/
if (ptr->key != MENU_KEY) {
window->UserData = ptr;
puts("Invalid node found. Window structure may be corrupted.");
puts("Please do not alter this program's menus again.");
goto quit;
}
.
63c
screen=IntuitionBase->FirstScreen; /* address of Workbench screen structure */
.
35,39c
struct node *next; /* list of new definitions */
short key; /* bug-repellent check value */
char text[46]; /* replacement text */
char *old_text; /* where old text is */
short old_item_width; /* what old width was */
struct MenuItem *altered; /* where old item is */
.
23a
/* this will ensure we don't de-allocate someone else's linked structure */
/* except in the case of a really, really big coincidence (this is checked */
/* when the items are added as well) */
#define MENU_KEY 0x1234
.
22d