Use external editor in 'commands' command

[Alfredo Ortega <ortegaalfredo@gmail.com>]

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Hi all,

I have made a small patch to the 'commands' command to allow the use
of an external editor to add or modify commands. This is convenient if
you are dealing with many commands per breakpoint.
The editor follows the behavior of the 'edit' command (/bin/ex by
default, or the 'EDITOR' environment variable)

Tested on i686-pc-linux-gnu, please tell me what do you think about it.

2009-01-14 Alfredo Ortega <ortegaalfredo@gmail.com>
    * breakpoint.c (commands_command,_initialize_breakpoint):
    Add the 'edit' keyword to the 'commands' command to allow the
    use of an external editor to add or modify commands.

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--- OLD/gdb/breakpoint.c	2009-01-14 17:46:26.000000000 -0200
+++ NEW/gdb/breakpoint.c	2009-01-14 19:32:40.000000000 -0200
@@ -585,14 +585,20 @@ condition_command (char *arg, int from_t
   error (_("No breakpoint number %d."), bnum);
 }
 
+#define COMMANDS_EDCOMMAND "edit"
+
 static void
 commands_command (char *arg, int from_tty)
 {
   struct breakpoint *b;
   char *p;
-  int bnum;
+  int bnum,fsize;
   struct command_line *l;
-
+  char vitmp[50];
+  char cmdline[100];
+  FILE *tmpstream=NULL;
+  char *editor;
+  
   /* If we allowed this, we would have problems with when to
      free the storage, if we change the commands currently
      being read from.  */
@@ -602,6 +608,41 @@ commands_command (char *arg, int from_tt
 
   p = arg;
   bnum = get_number (&p);
+  vitmp[0]=0;
+  /* Edit commands with external editor */
+  if (!strcmp(COMMANDS_EDCOMMAND,p))	{
+	/* Generates the temporal file name*/
+	/* vitmp = tempnam(NULL,".gdb"); this is more secure according to man mkstemp, but gcc complains... */
+	p=NULL;
+	strcpy(vitmp,"/tmp/.gdbXXXXXX");
+	if (mkstemp(vitmp)<0) return;
+	ALL_BREAKPOINTS (b)
+		if (b->number == bnum)
+			{
+			if (&b->commands)	{
+				/* commands exists, must dump them to the temporal file */
+				tmpstream=fopen(vitmp,"w");
+				l = b->commands;
+				while(l)	{
+					fsize=0;
+					fsize+=fwrite(l->line,1,strlen(l->line),tmpstream);
+					fsize+=fwrite("\n",1,strlen("\n"),tmpstream);
+					if (fsize<strlen(l->line)+1) {
+						fclose(tmpstream);
+						unlink(vitmp);
+						return;
+						};
+					l = l->next;
+					}
+				fclose(tmpstream);
+				}
+			/* Edit the file */
+			if ((editor = (char *) getenv ("EDITOR")) == NULL)
+				editor = "/bin/ex";
+			snprintf(cmdline,sizeof(cmdline),"%s \"%s\"",editor,vitmp);
+			if (system(cmdline)<0) return;
+    			}
+	}
 
   if (p && *p)
     error (_("Unexpected extra arguments following breakpoint number."));
@@ -609,17 +650,31 @@ commands_command (char *arg, int from_tt
   ALL_BREAKPOINTS (b)
     if (b->number == bnum)
       {
-	char *tmpbuf = xstrprintf ("Type commands for when breakpoint %d is hit, one per line.", 
+	if(vitmp[0])	{
+		/* redirect instream */
+		tmpstream=instream;
+		instream=fopen(vitmp,"r");
+		l = read_command_lines (NULL, from_tty, 1);
+		}
+	else	{
+		char *tmpbuf = xstrprintf ("Type commands for when breakpoint %d is hit, one per line.", 
 				 bnum);
-	struct cleanup *cleanups = make_cleanup (xfree, tmpbuf);
-	l = read_command_lines (tmpbuf, from_tty, 1);
-	do_cleanups (cleanups);
+		struct cleanup *cleanups = make_cleanup (xfree, tmpbuf);
+		l = read_command_lines (tmpbuf, from_tty, 1);
+		do_cleanups (cleanups);
+		}
 	free_command_lines (&b->commands);
 	b->commands = l;
 	breakpoints_changed ();
 	observer_notify_breakpoint_modified (b->number);
+	if(vitmp[0])	{
+		/* restore instream */
+		instream=tmpstream;
+		/* erase temporal file */
+		unlink(vitmp);
+		}
 	return;
-    }
+       }
   error (_("No breakpoint number %d."), bnum);
 }
 
@@ -8103,6 +8158,9 @@ Usage is `ignore N COUNT'."));
   add_com ("commands", class_breakpoint, commands_command, _("\
 Set commands to be executed when a breakpoint is hit.\n\
 Give breakpoint number as argument after \"commands\".\n\
+After the command number you can enter the `edit' keyword, and then you can \n\
+use the external editor to add or modify commands.\n\
+Uses EDITOR environment variable contents as editor (or ex as default).\n\
 With no argument, the targeted breakpoint is the last one set.\n\
 The commands themselves follow starting on the next line.\n\
 Type a line containing \"end\" to indicate the end of them.\n\