Re: [PATCH] [gdb/tui] Fix tui compact-source a bit more

[Tom de Vries <tdevries@suse.de>]

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On 5/11/23 16:55, Simon Marchi wrote:
> On 5/10/23 09:21, Tom de Vries via Gdb-patches wrote:
>> Andrew pointed out that the behaviour as tested in gdb.tui/compact-source.exp
>> is incorrect:
>> ...
>> 0 +-compact-source.c--------------------------------------------------------+
>> 1 |___3_{                                                                   |
>> 2 |___4_  return 0;                                                         |
>> 3 |___5_}                                                                   |
>> 4 |___6_                                                                    |
>> 5 |___7_                                                                    |
>> 6 |___8_                                                                    |
>> 7 |___9_                                                                    |
>> 8 +-------------------------------------------------------------------------+
>> ...
>>
>> The last line number in the source file is 5, and there are 7 lines to display
>> source lines, so if we'd scroll all the way down, the first line number in the
>> source window would be 5, and the last one would be 11.
>>
>> To represent 11 we'd need 2 digits, so we expect to see ___04_ here instead of
>> ___4_, even though all line numbers currently in the src window (3-9) can be
>> represented with only 1 digit.
> 
> Just wondering: it makes sense to let the user scroll down all the way,
> until the point where line 5 is the first line in the window.  However,
> do we need to print line numbers for lines that are after the end of the
> source file?  In other words, could we leave lines 6-11 blank, and
> therefore we could keep using just one digit?

This demonstrator patch implements that approach.

Thanks,
- Tom

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From 31b7ab1f107b36bf440f89f732e4b46d96d0faa2 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Thu, 11 May 2023 19:43:32 +0200
Subject: [PATCH] [gdb/tui] Don't show line number for lines not in source file

---
 gdb/testsuite/gdb.tui/compact-source.exp |  2 +-
 gdb/tui/tui-source.c                     | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/gdb/testsuite/gdb.tui/compact-source.exp b/gdb/testsuite/gdb.tui/compact-source.exp
index f972d961d72..59e858a503f 100644
--- a/gdb/testsuite/gdb.tui/compact-source.exp
+++ b/gdb/testsuite/gdb.tui/compact-source.exp
@@ -64,7 +64,7 @@ foreach_with_prefix src_window_size {7 8} {
     if { $max_line_nr_in_source_window == 9 } {
 	set re_left_margin "___4_"
     } elseif { $max_line_nr_in_source_window == 10 }  {
-	set re_left_margin "___04_"
+	set re_left_margin "___4_"
     } else {
 	error "unhandled max_line_nr_in_source_window"
     }
diff --git a/gdb/tui/tui-source.c b/gdb/tui/tui-source.c
index 9d0376000de..57f9a62c659 100644
--- a/gdb/tui/tui-source.c
+++ b/gdb/tui/tui-source.c
@@ -80,7 +80,7 @@ tui_source_window::set_contents (struct gdbarch *arch,
       /* Solaris 11+gcc 5.5 has ambiguous overloads of log10, so we
 	 cast to double to get the right one.  */
       int lines_in_file = offsets->size ();
-      int max_line_nr = lines_in_file + nlines - 1;
+      int max_line_nr = lines_in_file;
       int digits_needed = 1 + (int)log10 ((double) max_line_nr);
       int trailing_space = 1;
       m_digits = digits_needed + trailing_space;
@@ -100,6 +100,8 @@ tui_source_window::set_contents (struct gdbarch *arch,
 	  text = tui_copy_source_line (&iter, &line_len);
 	  m_max_length = std::max (m_max_length, line_len);
 	}
+      else
+	cur_line_no = -1;
 
       /* Set whether element is the execution point
 	 and whether there is a break point on it.  */
@@ -233,11 +235,19 @@ tui_source_window::display_start_addr (struct gdbarch **gdbarch_p,
 void
 tui_source_window::show_line_number (int offset) const
 {
-  int lineno = m_content[0].line_or_addr.u.line_no + offset;
+  int lineno = m_content[offset].line_or_addr.u.line_no;
   char text[20];
   char space = tui_left_margin_verbose ? '_' : ' ';
-  xsnprintf (text, sizeof (text),
-	     tui_left_margin_verbose ? "%0*d%c" : "%*d%c", m_digits - 1,
-	     lineno, space);
+  if (lineno == -1)
+    {
+      for (int i = 0; i <= m_digits; ++i)
+	text[i] = (i == m_digits) ? '\0' : space;
+    }
+  else
+    {
+      xsnprintf (text, sizeof (text),
+		 tui_left_margin_verbose ? "%0*d%c" : "%*d%c", m_digits - 1,
+		 lineno, space);
+    }
   waddstr (handle.get (), text);
 }

base-commit: 38b95a529385e32adc39428231c6fc8b0e8d6f21
-- 
2.35.3