Revert function pointers for rl_complete() and rl_list_possib() introduced in 0.2.2.

Instead merge afd8b4de9dca8ec6afc3 from http://github.com/heimdal/heimdal.git project.
This lets rl_complete() and rl_list_possib() become wrapper functions calling a set of
function pointers, set using rl_set_complete_func() and rl_set_list_possib_funct().

Each wrapper has a fallback to do filename completion, which in turn can be disabled
by leaving out --enable-default-complete from the configure line.

This change, admittedly quite intrusive for a library, is a better implementation in
many ways.  For one it is much more readable, but it also enables further adoption of
other editline forks as well as a simpler implementation of GNU Readline function
pointers rl_completion_entry_function and rl_attempted_completion_function at a later
stage.

My apologies to everyone for whom this change breaks backwards compatibility.  For
help on converting your code, please see examples/cli.c.

examples/cli.c

@@ -84,8 +84,8 @@ int main(int ac __attribute__ ((unused)), char *av[] __attribute__ ((unused)))
    char	*prompt = "cli> ";
 
    /* Setup callbacks */
-   rl_complete = &my_rl_complete;
-   rl_list_possib = &my_rl_list_possib;
+   rl_set_complete_func(&my_rl_complete);
+   rl_set_list_possib_func(&my_rl_list_possib);
 
    while ((line = readline(prompt)) != NULL) {
       (void)printf("\t\t\t|%s|\n", line);

include/editline.h

@@ -21,12 +21,18 @@
 #ifndef __EDITLINE_H__
 #define __EDITLINE_H__
 
+/* Editline specific types, despite rl_ prefix.  From Heimdal project. */
+typedef char* (*rl_complete_func_t)(char*, int*);
+typedef int (*rl_list_possib_func_t)(char*, char***);
+
 /* Display print 8-bit chars as `M-x' or as the actual 8-bit char?  (Default:1) */
 extern int rl_meta_chars;
 
-/* Assign these to get command completion, see cli.c for example usage. */
-extern char *(*rl_complete)   (char *token, int *match);
-extern int   (*rl_list_possib)(char *token, char ***av);
+/* Use these functions to set custom command/file completion, see cli.c for example usage. */
+rl_complete_func_t    rl_set_complete_func(rl_complete_func_t func);
+rl_list_possib_func_t rl_set_list_possib_func(rl_list_possib_func_t func);
+
+/* Editline specific functions. */
 
 /* For compatibility with FSF readline. */
 extern int         rl_point;

src/complete.c

@@ -156,9 +156,19 @@ static int SplitPath(char *path, char **dirpart, char **filepart)
     return 0;
 }
 
+static rl_complete_func_t el_complete_func = NULL;
+
+/* For compatibility with the Heimdal project. */
+rl_complete_func_t rl_set_complete_func(rl_complete_func_t func)
+{
+    rl_complete_func_t old = el_complete_func;
+    el_complete_func = func;
+    return old;
+}
+
 /* Attempt to complete the pathname, returning an allocated copy.
- * Fill in *unique if we completed it, or set it to 0 if ambiguous. */
-char *default_rl_complete(char *pathname, int *unique)
+ * Fill in *match if we completed it, or set it to 0 if ambiguous. */
+char *el_filename_complete(char *pathname, int *match)
 {
     char        **av;
     char        *dir;
@@ -185,7 +195,7 @@ char *default_rl_complete(char *pathname, int *unique)
     len = strlen(file);
     if (ac == 1) {
         /* Exactly one match -- finish it off. */
-        *unique = 1;
+        *match = 1;
         j = strlen(av[0]) - len + 2;
 	p = malloc(sizeof(char) * (j + 1));
         if (p) {
@@ -200,7 +210,7 @@ char *default_rl_complete(char *pathname, int *unique)
         }
     }
     else {
-        *unique = 0;
+        *match = 0;
         if (len) {
             /* Find largest matching substring. */
             for (i = len, end = strlen(av[0]); i < end; i++)
@@ -229,8 +239,30 @@ char *default_rl_complete(char *pathname, int *unique)
     return p;
 }
 
-/* Return all possible completions. */
-int default_rl_list_possib(char *pathname, char ***avp)
+char *rl_complete(char *token, int *match)
+{
+    if (el_complete_func)
+	return el_complete_func(token, match);
+
+#ifdef CONFIG_DEFAULT_COMPLETE
+    return el_filename_complete(token, match);
+#else
+    return NULL;
+#endif
+}
+
+static rl_list_possib_func_t el_list_possib_func = NULL;
+
+/* For compatibility with the Heimdal project. */
+rl_list_possib_func_t rl_set_list_possib_func(rl_list_possib_func_t func)
+{
+    rl_list_possib_func_t old = el_list_possib_func;
+    el_list_possib_func = func;
+    return old;
+}
+
+/* Default possible completions. */
+int el_filename_list_possib(char *pathname, char ***av)
 {
     char        *dir;
     char        *file;
@@ -239,13 +271,27 @@ int default_rl_list_possib(char *pathname, char ***avp)
     if (SplitPath(pathname, &dir, &file) < 0)
         return 0;
 
-    ac = FindMatches(dir, file, avp);
+    ac = FindMatches(dir, file, av);
     free(dir);
     free(file);
 
     return ac;
 }
 
+/* Return all possible completions. */
+int rl_list_possib(char *token, char ***av)
+{
+    if (el_list_possib_func)
+	return el_list_possib_func(token, av);
+
+#ifdef CONFIG_DEFAULT_COMPLETE
+    return el_filename_list_possib(token, av);
+#else
+    return 0;
+#endif
+}
+
+
 /**
  * Local Variables:
  *  version-control: t

src/editline.c

@@ -115,8 +115,6 @@ const char       *rl_readline_name;/* Set by calling program, for conditional pa
 
 /* User definable callbacks. */
 char **(*rl_attempted_completion_function)(const char *token, int start, int end);
-char  *(*rl_comlete)(char *token, int *match);
-int    (*rl_list_possib)(char *token, char ***av);
 
 /* Declarations. */
 static char     *editinput(void);
@@ -1018,20 +1016,6 @@ void rl_reset_terminal(char *p __attribute__((__unused__)))
 
 void rl_initialize(void)
 {
-#ifdef CONFIG_DEFAULT_COMPLETE
-    int done = 0;
-
-    if (!done)
-    {
-        if (!rl_complete)
-            rl_complete = &default_rl_complete;
-
-        if (!rl_list_possib)
-            rl_list_possib = &default_rl_list_possib;
-
-        done = 1;
-    }
-#endif
 }
 
 char *readline(const char *prompt)
@@ -1155,10 +1139,6 @@ static el_status_t c_possible(void)
     char        *word;
     int         ac;
 
-    if (!rl_list_possib) {
-        return ring_bell();
-    }
-
     word = find_word();
     ac = rl_list_possib((char *)word, (char ***)&av);
     if (word)
@@ -1171,6 +1151,7 @@ static el_status_t c_possible(void)
 
         return CSmove;
     }
+
     return ring_bell();
 }
 
@@ -1182,10 +1163,6 @@ static el_status_t c_complete(void)
     int         unique;
     el_status_t s = 0;
 
-    if (!rl_complete) {
-        return ring_bell();
-    }
-
     word = find_word();
     p = (char *)rl_complete((char *)word, &unique);
     if (word)

src/editline.h

@@ -73,12 +73,10 @@ extern int	rl_quit;
 #ifdef CONFIG_SIGSTOP
 extern int	rl_susp;
 #endif
-#ifdef CONFIG_DEFAULT_COMPLETE
-extern char	*default_rl_complete(char *pathname, int *unique);
-extern int	default_rl_list_possib(char *pathname, char ***avp);
-#endif
-extern void     rl_ttyset(int Reset);
-extern void	rl_add_slash(char *path, char *p);
+void  rl_ttyset(int Reset);
+void  rl_add_slash(char *path, char *p);
+char *rl_complete(char *token, int *match);
+int   rl_list_possib(char *token, char ***av);
 
 #ifndef HAVE_STDLIB_H
 extern char	*getenv(const char *name);