Re: PATCH: documentation on keymap selection

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx> wrote:
> It doesn't address the issue that "bindkey -lL" lies about aliased
> keymaps.

This does.  It's minor, but it's a real gap --- in addition to not
knowing which keymaps are aliases for others, you can't even find out
trivially whether you're "in emacs mode" or "in vi mode".  The inverted
commas are because technically you never are, you just have some keymap
or other linked to main which happens to have a set of emacs-like or
vi-like bindings.  However, by keeping track of names of keymaps that
aren't "main" we can give a consistent account of what's happening such
that in the normal cases it does look exactly like you're in emacs or vi
mode.

Index: Doc/Zsh/zle.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/zle.yo,v
retrieving revision 1.84
diff -p -u -r1.84 zle.yo
--- Doc/Zsh/zle.yo	1 Sep 2010 16:39:32 -0000	1.84
+++ Doc/Zsh/zle.yo	3 Sep 2010 21:53:07 -0000
@@ -175,7 +181,8 @@ startitem()
 item(tt(-l))(
 List all existing keymap names.  If the tt(-L)
 option is also used, list in the form of tt(bindkey)
-commands to create the keymaps.
+commands to create the keymaps; this combination also shows
+which keymap is linked to `tt(main)', if any.
 )
 item(tt(-d))(
 Delete all existing keymaps and reset to the default state.
Index: Src/Zle/zle_keymap.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Zle/zle_keymap.c,v
retrieving revision 1.32
diff -p -u -r1.32 zle_keymap.c
--- Src/Zle/zle_keymap.c	28 Jan 2009 09:32:01 -0000	1.32
+++ Src/Zle/zle_keymap.c	3 Sep 2010 21:53:07 -0000
@@ -58,11 +58,24 @@ struct keymapname {
     Keymap keymap;	/* the keymap itsef */
 };
 
+/* Can't be deleted (.safe) */
 #define KMN_IMMORTAL (1<<1)
 
 struct keymap {
     Thingy first[256];	/* base binding of each character */
     HashTable multi;	/* multi-character bindings */
+    /*
+     * The "real" name of this keymap.
+     * For an aliased keymap, this is the first name to be defined.
+     * If this is deleted but there are other names we randomly pick another
+     * one, avoiding the name "main".  The principal use
+     * for this is to make it clear what "main" is aliased to.
+     *
+     * If "main" is the only name for this map, this will be NULL.
+     * That's fine, there's no alias.  We'll pick a primary if we
+     * alias "main" again.
+     */
+    KeymapName primary;
     int flags;		/* various flags (see below) */
     int rc;		/* reference count */
 };
@@ -162,6 +175,70 @@ makekeymapnamnode(Keymap keymap)
     return kmn;
 }
 
+
+/*
+ * Reference a keymap from a keymapname.
+ * Used when linking keymaps.  This includes the first link to a
+ * newly created keymap.
+ */
+
+static void
+refkeymap_by_name(KeymapName kmn)
+{
+    refkeymap(kmn->keymap);
+    if (!kmn->keymap->primary && strcmp(kmn->nam, "main") != 0)
+	kmn->keymap->primary = kmn;
+}
+
+/*
+ * Communication to keymap scanner when looking for a new primary name.
+ */
+static Keymap km_rename_me;
+
+/* Find a new primary name for a keymap.  See below. */
+
+static void
+scanprimaryname(HashNode hn, int ignored)
+{
+    KeymapName n = (KeymapName) hn;
+
+    (void)ignored;
+
+    /* Check if we've already found a new primary name. */
+    if (km_rename_me->primary)
+	return;
+    /* Don't use "main". */
+    if (!strcmp(n->nam, "main"))
+	return;
+    if (n->keymap == km_rename_me)
+	km_rename_me->primary = n;
+}
+
+/*
+ * Unreference a keymap from a keymapname.
+ * Used when unlinking keymaps to ensure there is still a primary
+ * name for the keymap, unless it is an unaliased "main".
+ */
+static void
+unrefkeymap_by_name(KeymapName kmname)
+{
+    Keymap km = kmname->keymap;
+    if (unrefkeymap(km) && km->primary == kmname) {
+	/*
+	 * The primary name for the keymap has gone,
+	 * but the keymap is still referred to; find a new primary name
+	 * for it.  Sort the keymap to make the result deterministic.
+	 */
+	/* Set the primary name to NULL so we can check if we've found one */
+	km->primary = NULL;
+	km_rename_me = km;
+	scanhashtable(keymapnamtab, 1, 0, 0, scanprimaryname, 0);
+	/* Just for neatness */
+	km_rename_me = NULL;
+    }
+}
+
+
 /**/
 static void
 freekeymapnamnode(HashNode hn)
@@ -169,7 +246,7 @@ freekeymapnamnode(HashNode hn)
     KeymapName kmn = (KeymapName) hn;
 
     zsfree(kmn->nam);
-    unrefkeymap(kmn->keymap);
+    unrefkeymap_by_name(kmn);
     zfree(kmn, sizeof(*kmn));
 }
 
@@ -354,7 +431,7 @@ linkkeymap(Keymap km, char *name, int im
 	    return 1;
 	if(n->keymap == km)
 	    return 0;
-	unrefkeymap(n->keymap);
+	unrefkeymap_by_name(n);
 	n->keymap = km;
     } else {
 	n = makekeymapnamnode(km);
@@ -362,21 +439,29 @@ linkkeymap(Keymap km, char *name, int im
 	    n->flags |= KMN_IMMORTAL;
 	keymapnamtab->addnode(keymapnamtab, ztrdup(name), n);
     }
-    refkeymap(km);
+    refkeymap_by_name(n);
     return 0;
 }
 
 /**/
-void refkeymap(Keymap km)
+void
+refkeymap(Keymap km)
 {
     km->rc++;
 }
 
+/* Unreference keymap, returning new reference count, 0 if deleted */
+
 /**/
-void unrefkeymap(Keymap km)
+int
+unrefkeymap(Keymap km)
 {
-    if (!--km->rc)
+    if (!--km->rc) {
 	deletekeymap(km);
+	return 0;
+    }
+
+    return km->rc;
 }
 
 /* Select a keymap as the current ZLE keymap.  Can optionally fall back *
@@ -734,10 +819,21 @@ scanlistmaps(HashNode hn, int list)
 {
     KeymapName n = (KeymapName) hn;
 
-    if(list) {
-	fputs("bindkey -N ", stdout);
-	if(n->nam[0] == '-')
-	    fputs("-- ", stdout);
+    if (list) {
+	Keymap km = n->keymap;
+	fputs("bindkey -", stdout);
+	if (km->primary && km->primary != n) {
+	    KeymapName pn = km->primary;
+	    fputs("A ", stdout);
+	    if (pn->nam[0] == '-')
+		fputs("-- ", stdout);
+	    quotedzputs(pn->nam, stdout);
+	    fputc(' ', stdout);
+	} else {
+	    fputs("N ", stdout);
+	    if(n->nam[0] == '-')
+		fputs("-- ", stdout);
+	}
 	quotedzputs(n->nam, stdout);
     } else
 	nicezputs(n->nam, stdout);

-- 
Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/