Module Name: src
Committed By: christos
Date: Mon May 9 21:25:11 UTC 2016
Modified Files:
src/lib/libedit: readline.c
Log Message:
The libedit implementation of history_get() also differs from the GNU
implementation: libedit goes to the entry with the given number
stored in the HistEvent structure, while GNU subtracts history_base,
then advances that many entries from the oldest one. If entries were
removed in between, GNU advances further than libedit.
The call sequence H_CURR, H_DELDATA, H_CURR, H_NEXT_EVDATA looks
weird, as if part of that must somehow be redundant. But actually,
the user interface is so counter-intuitive that every single step
is really required.
- The first H_CURR is needed to be able to go back after an error.
- The H_DELDATA is needed to move the cursor. Even though it takes
a pointer to ev, that structure is not filled in when the call
succeeds. H_DELDATA only moves the cursor, it doesn't tell us
the new event number.
- Consequently, the second H_CURR is required to get ev.num filled
in. But it doesn't return the data because ev has no field for
that.
- So even though the cursor is already positioned correctly,
H_NEXT_EVDATA is needed as the final step merely to get the data.
(Ingo Schwarze)
To generate a diff of this commit:
cvs rdiff -u -r1.130 -r1.131 src/lib/libedit/readline.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libedit/readline.c
diff -u src/lib/libedit/readline.c:1.130 src/lib/libedit/readline.c:1.131
--- src/lib/libedit/readline.c:1.130 Sun May 8 16:15:00 2016
+++ src/lib/libedit/readline.c Mon May 9 17:25:11 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: readline.c,v 1.130 2016/05/08 20:15:00 christos Exp $ */
+/* $NetBSD: readline.c,v 1.131 2016/05/09 21:25:11 christos Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
#include "config.h"
#if !defined(lint) && !defined(SCCSID)
-__RCSID("$NetBSD: readline.c,v 1.130 2016/05/08 20:15:00 christos Exp $");
+__RCSID("$NetBSD: readline.c,v 1.131 2016/05/09 21:25:11 christos Exp $");
#endif /* not lint && not SCCSID */
#include <sys/types.h>
@@ -1400,25 +1400,37 @@ history_get(int num)
if (h == NULL || e == NULL)
rl_initialize();
+ if (num < history_base)
+ return NULL;
+
/* save current position */
if (history(h, &ev, H_CURR) != 0)
return NULL;
curr_num = ev.num;
- /* start from the oldest */
- if (history(h, &ev, H_LAST) != 0)
- return NULL; /* error */
-
- /* look forwards for event matching specified offset */
- if (history(h, &ev, H_NEXT_EVDATA, num, &she.data))
- return NULL;
+ /*
+ * use H_DELDATA to set to nth history (without delete) by passing
+ * (void **)-1 -- as in history_set_pos
+ */
+ if (history(h, &ev, H_DELDATA, num - history_base, (void **)-1) != 0)
+ goto out;
+ /* get current entry */
+ if (history(h, &ev, H_CURR) != 0)
+ goto out;
+ if (history(h, &ev, H_NEXT_EVDATA, ev.num, &she.data) != 0)
+ goto out;
she.line = ev.str;
/* restore pointer to where it was */
(void)history(h, &ev, H_SET, curr_num);
return &she;
+
+out:
+ /* restore pointer to where it was */
+ (void)history(h, &ev, H_SET, curr_num);
+ return NULL;
}
