Patchwork TUI: Expand TABs into spaces

login
register
mail settings
Submitter Eli Zaretskii
Date Jan. 31, 2015, 8:57 a.m.
Message ID <83wq43jpjk.fsf@gnu.org>
Download mbox | patch
Permalink /patch/4856/
State New
Headers show

Comments

Eli Zaretskii - Jan. 31, 2015, 8:57 a.m.
> From: Doug Evans <xdje42@gmail.com>
> Cc: gdb-patches@sourceware.org
> Date: Tue, 27 Jan 2015 00:06:12 -0800
> 
> > I did that below, but since tui_register_format is its only user,
> > keeping that function in tui-regs.c would have allowed us to make it
> > static.  Wouldn't that be slightly better?
> 
> That's not an invalid viewpoint, and if you want to go
> that route, fine by me.  One argument for going that route
> is that if another user comes along one can always make
> it public later.  Alas that doesn't always happen, and one
> ends up writing something that already exists.
> [If a year from now I need something like that the last
> place I'm going to look is tui-regs.c, whereas I will at least look
> through all the headers and generic-looking files for something.
> I wish I had a previous example at hand, I've paged out the details
> from memory and all that's left is wanting to avoid that.
> IIRC we've even had cases where something generic was used by
> multiple callers, then only one, and then someone moved it and
> made it static.  If there were multiple callers once there may
> be again (depending on the situation of course) so if I'm given the
> choice I wouldn't have made that move.]
> [Also, one could argue that this function isn't even tui-specific
> and thus should go in something like gdb/utils.c or even libiberty.
> Keeping it in tui just violates what I said above about being in
> the last place someone would look.
> I opted for not getting too carried away with things: I don't
> yet see a need for expanding tabs to spaces outside of tui,
> but I could be wrong of course.  Plus I wouldn't impose spending
> any time going back and forth picking the absolute best location,
> there are far more important things, and one could argue I've made
> you read too much already.]
> [OTOOH :-), if I hadn't said at least some of this the probability
> is too high that someone else would.  Bleah.
> [Not saying it would be you though!]]
> 
> So to make a long story short, feel free to leave it where it is or
> make it static.

I left it where it is, given that the pros and cons are inconclusive.

> > +/* Utility function to expand TABs in a STRING into spaces.  STRING
> > +   will be displayed starting at column COL.  The returned expanded
> > +   string is malloc'ed.  */
> 
> blank line between function comment and definition
> [I realize tui_get_register doesn't do that, but best do that with
> new code.]

Done.

> Also, I'm guessing that newlines in STRING isn't supported here, right?
> If so, mention that in the function comment.

Done.

> One could even add an assert like:
> 
>   gdb_assert (strchr (string, '\n') == NULL);
> 
> or some such.

I didn't do this, I think that'd be too much.  Having a slightly
messed-up screen is far better than having to abort the debug session,
if we ever get to this problem.  The mess-up will most probably be
reported, and we will fix it.

> > +/* Expand TABs into spaces.  */
> 
> For reference sake, there are multiple schools of thought, and no
> fixed convention in gdb, for whether to put a comment here, and
> what it should look like.  No need to change anything, and I can
> go into details if you want.  Just wanted to mention the issue,
> and the acceptable choice of not having any comment here.

I had in the past requests to add such comments, so at least some of
the maintainers favor them.  I left that comment intact.

The patch as I pushed it appears below.  Thanks again for reviewing
it.

commit 312809f8838911dabff84d7ad3ccf341307d2b19
Author: Eli Zaretskii <eliz@gnu.org>
Date:   Sat Jan 31 10:47:14 2015 +0200

    Make sure TABs are expanded in TUI windows on MS-Windows.
    
    gdb/
    2015-01-31  Eli Zaretskii  <eliz@gnu.org>
    
    	* tui/tui-io.c (tui_expand_tabs): New function.
    	(tui_puts, tui_redisplay_readline): Expand TABs into the
    	appropriate number of spaces.
    	* tui/tui-regs.c: Include tui-io.h.
    	(tui_register_format): Call tui_expand_tabs to expand TABs into
    	the appropriate number of spaces.
    	* tui/tui-io.h: Add prototype for tui_expand_tabs.

Patch

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 58f5a7b..51f1714 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@ 
+2015-01-31  Eli Zaretskii  <eliz@gnu.org>
+
+	* tui/tui-io.c (tui_expand_tabs): New function.
+	(tui_puts, tui_redisplay_readline): Expand TABs into the
+	appropriate number of spaces.
+	* tui/tui-regs.c: Include tui-io.h.
+	(tui_register_format): Call tui_expand_tabs to expand TABs into
+	the appropriate number of spaces.
+	* tui/tui-io.h: Add prototype for tui_expand_tabs.
+
 2015-01-30  Doug Evans  <dje@google.com>
 
 	* NEWS: "info source" command now display producer string if present.
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 7e8a3bc..19e9485 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -178,7 +178,20 @@ 
       else if (tui_skip_line != 1)
         {
           tui_skip_line = -1;
-          waddch (w, c);
+	  /* Expand TABs, since ncurses on MS-Windows doesn't.  */
+	  if (c == '\t')
+	    {
+	      int line, col;
+
+	      getyx (w, line, col);
+	      do
+		{
+		  waddch (w, ' ');
+		  col++;
+		} while ((col % 8) != 0);
+	    }
+	  else
+	    waddch (w, c);
         }
       else if (c == '\n')
         tui_skip_line = -1;
@@ -256,6 +269,16 @@ 
           waddch (w, '^');
           waddch (w, CTRL_CHAR (c) ? UNCTRL (c) : '?');
 	}
+      else if (c == '\t')
+	{
+	  /* Expand TABs, since ncurses on MS-Windows doesn't.  */
+	  getyx (w, line, col);
+	  do
+	    {
+	      waddch (w, ' ');
+	      col++;
+	    } while ((col % 8) != 0);
+	}
       else
 	{
           waddch (w, c);
@@ -724,6 +747,59 @@ 
   return ch;
 }
 
+/* Utility function to expand TABs in a STRING into spaces.  STRING
+   will be displayed starting at column COL, and is assumed to include
+   no newlines.  The returned expanded string is malloc'ed.  */
+
+char *
+tui_expand_tabs (const char *string, int col)
+{
+  int n_adjust;
+  const char *s;
+  char *ret, *q;
+
+  /* 1. How many additional characters do we need?  */
+  for (n_adjust = 0, s = string; s; )
+    {
+      s = strpbrk (s, "\t");
+      if (s)
+	{
+	  col += (s - string) + n_adjust;
+	  /* Adjustment for the next tab stop, minus one for the TAB
+	     we replace with spaces.  */
+	  n_adjust += 8 - (col % 8) - 1;
+	  s++;
+	}
+    }
+
+  /* Allocate the copy.  */
+  ret = q = xmalloc (strlen (string) + n_adjust + 1);
+
+  /* 2. Copy the original string while replacing TABs with spaces.  */
+  for (s = string; s; )
+    {
+      char *s1 = strpbrk (s, "\t");
+      if (s1)
+	{
+	  if (s1 > s)
+	    {
+	      strncpy (q, s, s1 - s);
+	      q += s1 - s;
+	      col += s1 - s;
+	    }
+	  do {
+	    *q++ = ' ';
+	    col++;
+	  } while ((col % 8) != 0);
+	  s1++;
+	}
+      else
+	strcpy (q, s);
+      s = s1;
+    }
+
+  return ret;
+}
 
 /* Cleanup when a resize has occured.
    Returns the character that must be processed.  */
diff --git a/gdb/tui/tui-io.h b/gdb/tui/tui-io.h
index 8f96cfe..3154eee 100644
--- a/gdb/tui/tui-io.h
+++ b/gdb/tui/tui-io.h
@@ -41,6 +41,9 @@ 
    changed the edited text.  */
 extern void tui_redisplay_readline (void);
 
+/* Expand TABs into spaces.  */
+extern char *tui_expand_tabs (const char *, int);
+
 extern struct ui_out *tui_out;
 extern struct ui_out *tui_old_uiout;
 
diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index b523e90..961491f 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -36,6 +36,7 @@ 
 #include "tui/tui-wingeneral.h"
 #include "tui/tui-file.h"
 #include "tui/tui-regs.h"
+#include "tui/tui-io.h"
 #include "reggroups.h"
 #include "valprint.h"
 
@@ -693,7 +694,9 @@  static enum tui_status tui_get_register (struct frame_info *frame,
   if (s && s[1] == 0)
     *s = 0;
 
-  ret = xstrdup (p);
+  /* Expand tabs into spaces, since ncurses on MS-Windows doesn't.  */
+  ret = tui_expand_tabs (p, 0);
+
   do_cleanups (cleanups);
 
   return ret;