From 403dfdc24b0a22f14ded69f6eb4f15dc529f6f10 Mon Sep 17 00:00:00 2001
From: Pavel Roskin <proski@gnu.org>
Date: Tue, 14 Aug 2001 04:48:26 +0000
Subject: [PATCH] * key.h (define_sequence): Change declaration to return int.
 * key.c (define_sequence): Return 1 on success, 0 on error. * learn.c
 (learn_button): Don't accept sequence if define_sequence() has failed.

---
 src/ChangeLog |  7 +++++++
 src/key.c     | 23 +++++++++++++++++------
 src/key.h     |  2 +-
 src/learn.c   | 10 ++++++++--
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index 1a151c8b6..b4f41bd74 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2001-08-14  Pavel Roskin  <proski@gnu.org>
+
+	* key.h (define_sequence): Change declaration to return int.
+	* key.c (define_sequence): Return 1 on success, 0 on error.
+	* learn.c (learn_button): Don't accept sequence if
+	define_sequence() has failed.
+
 2001-08-12  Pavel Roskin  <proski@gnu.org>
 
 	* learn.c (learn_save): Fix memory leak.
diff --git a/src/key.c b/src/key.c
index 817315c12..b2d2517cd 100644
--- a/src/key.c
+++ b/src/key.c
@@ -370,24 +370,28 @@ static int push_char (int c)
     return 1;
 }
 
-void define_sequence (int code, char *seq, int action)
+/*
+ * Return 1 on success, 0 on error.
+ * An error happens if SEQ is a beginning of an existing longer sequence.
+ */
+int define_sequence (int code, char *seq, int action)
 {
     key_def *base;
 
     if (strlen (seq) > sizeof (seq_buffer)-1)
-	return;
+	return 0;
     
     for (base = keys; (base != 0) && *seq; ){
 	if (*seq == base->ch){
 	    if (base->child == 0){
 		if (*(seq+1)){
 		    base->child = create_sequence (seq+1, code, action);
-		    return;
+		    return 1;
 		} else {
-		    /* The sequence clashes */
+		    /* The sequence matches an existing one.  */
                     base->code = code;
                     base->action = action;
-		    return;
+		    return 1;
 		}
 	    } else {
 		base = base->child;
@@ -398,11 +402,18 @@ void define_sequence (int code, char *seq, int action)
 		base = base->next;
 	    else {
 		base->next = create_sequence (seq, code, action);
-		return;
+		return 1;
 	    }
 	}
     }
+
+    if (!*seq) {
+	/* Attempt to redefine a sequence with a shorter sequence.  */
+	return 0;
+    }
+
     keys = create_sequence (seq, code, action);
+    return 1;
 }
 
 static int *pending_keys;
diff --git a/src/key.h b/src/key.h
index 558f1c14b..32bd8356c 100644
--- a/src/key.h
+++ b/src/key.h
@@ -63,7 +63,7 @@ int is_quit_char (int c);
 #define MCKEY_MOUSE     -2
 
 void do_define_key (int code, char *strcap);
-void define_sequence (int code, char *seq, int action);
+int define_sequence (int code, char *seq, int action);
 
 /* internally used in key.c, defined in keyxtra.c */
 void load_xtra_key_defines (void);
diff --git a/src/learn.c b/src/learn.c
index 2246c8bd9..4a0d06179 100644
--- a/src/learn.c
+++ b/src/learn.c
@@ -107,6 +107,8 @@ _("Please press the %s\n"
 	/* Esc hides the dialog and do not allow definitions of
 	 * regular characters
 	 */
+	int seq_ok;
+
 	if (*seq && strcmp (seq, "\\e") && strcmp (seq, "\\e\\e")
 	    && strcmp (seq, "^m" ) 
             && (seq [1] || (*seq < ' ' || *seq > '~'))){
@@ -114,9 +116,13 @@ _("Please press the %s\n"
 	    learnchanged = 1;
 	    learnkeys [action - B_USER].sequence = seq;
 	    seq = convert_controls (seq);
-	    define_sequence (key_name_conv_tab [action - B_USER].code, seq, 
-			     MCKEY_NOACTION);
+	    seq_ok = define_sequence (key_name_conv_tab [action - B_USER].code,
+				      seq, MCKEY_NOACTION);
 	} else {
+	    seq_ok = 0;
+	}
+
+	if (!seq_ok) {
 	    message (0, _(" Cannot accept this key "),
 		_(" You have entered \"%s\""), seq);
 	}