Dear screen developers,
I see a bug with auto-aka feature in screen 4.0.3. To reproduce:
0. use bash or another shell with prompt ending in '$ '. Ensure that
the null title command, "<esc>k<esc><backslash>", is included in
the shell prompt.
Below, ^A means ctrl+a. Press the following key sequence:
1. ^A:shelltitle "$ |foo"
2. ^Ac
3. ^AA bar
4. sleep 2
Expected:
1. Sets the default title for new windows to 'foo'
2. Opens a new window with title 'foo'
3. Overrides the title of the new window to 'bar'
4. Invokes a sleep command in the new window
We expect at this point the window's title to turn into 'sleep' for 2
seconds, then return back to 'bar' as requested interactively by the
user. However, screen-4.0.3 erroneously resets the title to the
session-wide default 'foo'.
The attached patch is a proposal for a fix of this issue. Moreover,
the arguments to the "title" command, the "-t" option, and the
"<esc>kWINDOWTITLE<esc>\" terminal sequence now undergo a similar
parsing of SEARCH|TITLE as known from "shelltitle". This enables
interactive and programmatic changes to windows in auto-aka state,
like in
/bin/echo -ne \\033k`pwd|sed 's/.*\///'`\\033\\\\
or in more sophisticated applications. Use the special title "|TITLE"
to disable the auto-aka heuristic in a window.
H-C
There is a small bug with screen's auto-aka feature. To reproduce:
0. use bash or another shell with prompt ending in '$ '. Ensure that
the null title command, "<esc>k<esc><backslash>", is included in
the shell prompt.
Below, ^A means ctrl+a. Press the following key sequence:
1. ^A:shelltitle "$ |foo"
2. ^Ac
3. ^AA bar
4. sleep 2
Expected:
1. Sets the default title for new windows to 'foo'
2. Opens a new window with title 'foo'
3. Overrides the title of the new window to 'bar'
4. Invokes a sleep command in the new window
We expect at this point the window's title to turn into 'sleep' for 2
seconds, then return back to 'bar' as requested interactively by the
user. However, screen-4.0.3 erroneously resets the title to the
session-wide default 'foo'.
The attached patch is a proposal for a fix of this issue. Moreover,
the special SEARCH|TITLE parsing of window names known from
"shelltitle" command is now also applied to
- the interactive "title" command,
- the "-t" option, and
- the "<esc>kWINDOWTITLE<esc>\" terminal sequence. (The latter can be
used in applications like
/bin/echo -ne \\033k`pwd|sed 's/.*\///'`\\033\\\\
to programmitically set the title of the current window.)
Use the special title "|TITLE" to disable the auto-aka heuristic in a
window.
h...@gmx.de
------------------------------------------------------------
--- screen-4.0.3.orig/ansi.c 2003-12-05 14:57:05.000000000 +0100
+++ screen-4.0.3/ansi.c 2009-07-23 16:28:38.000000000 +0200
@@ -1557,12 +1557,21 @@
LAY_DISPLAYS(&curr->w_layer, AddStr(curr->w_string));
break;
case AKA:
- if (curr->w_title == curr->w_akabuf && !*curr->w_string)
- break;
- ChangeAKA(curr, curr->w_string, strlen(curr->w_string));
- if (!*curr->w_string)
- curr->w_autoaka = curr->w_y + 1;
+ if (*curr->w_string)
+ {
+ ChangeAKA(curr, NULL, 0); /* reset current command aka */
+ ProcessDefaultAKA(curr, curr->w_string);
+ ChangeAKA(curr, NULL, 0);
+ }
+ else
+ {
+ if (curr->w_title == curr->w_akabuf) break;
+
+ ChangeAKA(curr, NULL, 0);
+ curr->w_autoaka = curr->w_y + 1;
+ }
break;
+
default:
break;
}
@@ -2191,10 +2200,13 @@
p->w_akachange[i++] = c;
}
p->w_akachange[i] = 0;
- p->w_title = p->w_akachange;
- if (p->w_akachange != p->w_akabuf)
- if (p->w_akachange[0] == 0 || p->w_akachange[-1] == ':')
- p->w_title = p->w_akabuf + strlen(p->w_akabuf) + 1;
+ if (p->w_title != p->w_akabuf)
+ {
+ p->w_title = p->w_akachange;
+ if (p->w_akachange != p->w_akabuf)
+ if (p->w_akachange[0] == 0 || p->w_akachange[-1] == ':')
+ p->w_title = p->w_akabuf + strlen(p->w_akabuf) + 1;
+ }
WindowChanged(p, 't');
WindowChanged((struct win *)0, 'w');
WindowChanged((struct win *)0, 'W');
@@ -2208,6 +2220,8 @@
register int len = strlen(wp->w_akabuf);
int y;
+ if (!len || wp->w_title == wp->w_akabuf) return;
+
y = (wp->w_autoaka > 0 && wp->w_autoaka <= wp->w_height) ? wp->w_autoaka - 1 : wp->w_y;
cols = wp->w_width;
try_line:
--- screen-4.0.3.orig/doc/screen.1 2003-12-05 14:51:57.000000000 +0100
+++ screen-4.0.3/doc/screen.1 2009-07-23 16:04:11.000000000 +0200
@@ -2885,6 +2885,15 @@
.I screen
prompts for one. This command was known as `aka' in previous
releases.
+.PP
+\fIwindowtitle\fP can be in the form \*Q\fIsearch|name\fP\*U
+in which case the special heuristic for displaying the currently
+running command is enabled. In a window under this heuristic,
+subsequent \fIwindowtitle\fP changes only affect the \fIname\fP part
+and thus leave the heuristic enabled. Use \fI|name\fP to disable the
+heuristic again.
+For further details about this heuristic, see the discussion
+entitled \*QTITLES (naming windows)\*U.
.sp
.ne 3
.BI "unsetenv " var
--- screen-4.0.3.orig/doc/screen.texinfo 2003-12-05 14:51:46.000000000 +0100
+++ screen-4.0.3/doc/screen.texinfo 2009-07-23 16:10:01.000000000 +0200
@@ -1943,6 +1943,14 @@
(@kbd{C-a A})@*
Set the name of the current window to @var{windowtitle}. If no name is
specified, screen prompts for one.
+
+...@var{windowtitle} can be in the form @var{search|name} in which case the
+special heuristic for displaying the currently running command is
+enabled (@pxref{Dynamic Titles}). In a window under this heuristic,
+subsequent @var{windowtitle} changes only affect the @var{name} part and
+thus leave the heuristic enabled. Use @var{|name} to disable the
+heuristic again.
+
@end deffn
@node Dynamic Titles, Title Prompts, Title Command, Naming Windows
@@ -1955,7 +1963,9 @@
the @var{name} ends in a @samp{:} @code{screen} will add what it
believes to be the current command running in the window to the end of
the specified name (e.g. @var{name:cmd}). Otherwise the current
-command name supersedes the shell name while it is running.
+command name supersedes the shell name while it is running. In a window
+under this heuristic the interactive title command (C-a A) changes only
+the @var{name} portion.
Here's how it works: you must modify your shell prompt to output a null
title-escape-sequence (@key{ESC} k @key{ESC} \) as a part of your prompt.
--- screen-4.0.3.orig/extern.h 2003-08-22 14:27:57.000000000 +0200
+++ screen-4.0.3/extern.h 2009-07-23 15:00:27.000000000 +0200
@@ -213,6 +213,8 @@
extern void ApplyAttrColor __P((int, struct mchar *));
extern void SwitchWindow __P((int));
extern int StuffKey __P((int));
+extern void ProcessDefaultAKA __P((struct win *, char *));
+
/* termcap.c */
extern int InitTermcap __P((int, int));
--- screen-4.0.3.orig/process.c 2003-09-18 14:53:54.000000000 +0200
+++ screen-4.0.3/process.c 2009-07-29 13:20:48.000000000 +0200
@@ -33,7 +33,6 @@
#include <sys/ioctl.h>
#endif
-
#include "config.h"
/* for solaris 2.1, Unixware (SVR4.2) and possibly others: */
@@ -124,7 +123,9 @@
static void Colonfin __P((char *, int, char *));
static void InputSelect __P((void));
static void InputSetenv __P((char *));
-static void InputAKA __P((void));
+static void SetDefaultAKA __P((char *));
+void ProcessDefaultAKA __P((struct win *, char *));
+static void InputDefaultAKA __P((void));
#ifdef MULTIUSER
static int InputSu __P((struct win *, struct acluser **, char *));
static void su_fin __P((char *, int, char *));
@@ -1886,9 +1887,12 @@
break;
case RC_TITLE:
if (*args == 0)
- InputAKA();
+ InputDefaultAKA();
else
- ChangeAKA(fore, *args, strlen(*args));
+ {
+ SetDefaultAKA(*args);
+ ChangeAKA(fore, NULL, 0);
+ }
break;
case RC_COLON:
Input(":", 100, INP_COOKED, Colonfin, NULL);
@@ -5046,6 +5050,62 @@
Msg(0, "%s", buf);
}
+/* Here's briefly how I think the autoaka feature is implemented.
+
+ w_akabuf is the buffer containing the raw title string.
+ w_title points to the current title.
+ w_akachange points to the null terminating w_title.
+
+ user title string > |bash > |root: bash
+
+ 1) at shell prompt (triggered in ansi.c by \033k\033\\ sequence)
+
+ w_akabuf > \0bash\0 > \0root:\0 bash\0
+ w_title bash\0 root:\0 bash\0
+ w_akachange \0 \0 bash\0
+
+ 2) when executing command (triggered in ansi.c by \n sequence)
+
+ w_akabuf > \0bashvi\0 > \0root:vi\0 bash\0
+ w_title vi\0 root:vi\0 bash\0
+ w_akachange vi\0 vi\0 bash\0
+
+*/
+
+static void
+SetDefaultAKA(buf)
+ char *buf;
+{
+ ProcessDefaultAKA(fore, buf);
+}
+
+void
+ProcessDefaultAKA(f, buf)
+ struct win *f;
+ char *buf;
+{
+ char *p;
+
+ if ((p = rindex(buf, '|')) != NULL)
+ {
+ if (p == buf) buf++; /* empty lookup, switch autoaka off again */
+ strncpy(f->w_akabuf, buf, sizeof(f->w_akabuf)-1);
+ p = f->w_akabuf + (p - buf);
+ if (p >= f->w_akabuf) *p = '\0';
+ p++;
+ f->w_title = p;
+ }
+ else
+ {
+ strncpy(f->w_title, buf,
+ sizeof(f->w_akabuf) - (f->w_title - f->w_akabuf));
+ }
+ f->w_akabuf[sizeof(f->w_akabuf)-1] = '\0';
+ f->w_akachange = f->w_title + strlen(f->w_title);
+
+ f->w_autoaka = f->w_y + 1;
+}
+
static void
AKAfin(buf, len, data)
char *buf;
@@ -5053,12 +5113,14 @@
char *data; /* dummy */
{
ASSERT(display);
- if (len && fore)
- ChangeAKA(fore, buf, strlen(buf));
+ if (len && fore) {
+ SetDefaultAKA(buf);
+ ChangeAKA(fore, NULL, 0);
+ }
}
static void
-InputAKA()
+InputDefaultAKA()
{
char *s, *ss;
int n;
