Allow using less horizontal space in TUI source window

The source window currently uses a field width of 6 for line numbers,
and it further aligns to the next tab stop.  This seemed a bit
wasteful of horizontal space to me, so I changed that in an earlier
patch.

However, that change wasn't universally popular.  This patch instead
adds the option to use less horizontal space in the TUI source window.

gdb/ChangeLog
2019-12-01  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.h (tui_copy_source_line): Add "ndigits"
	parameter.
	* tui/tui-winsource.c (tui_copy_source_line): Add "ndigits"
	parameter.
	* tui/tui-win.h (compact_source): Declare.
	* tui/tui-win.c (compact_source): New global.
	(tui_set_compact_source, tui_show_compact_source): New functions.
	(_initialize_tui_win): Add "compact-source" setting.
	* tui/tui-source.c (tui_source_window::set_contents): Handle
	compact_source setting.
	* tui/tui-disasm.c (tui_disasm_window::set_contents): Update.
	* NEWS: Document new setting.

gdb/doc/ChangeLog
2019-12-01  Tom Tromey  <tom@tromey.com>

	* gdb.texinfo (TUI Configuration): Document new setting.

Change-Id: I46ce9a68b12c9c79332d510f9c14b3c84b7efadd

6 files changed, 67 insertions, 11 deletions

diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c
index 8d5512e..9819cb9 100644
--- a/gdb/tui/tui-disasm.c
+++ b/gdb/tui/tui-disasm.c
@@ -245,7 +245,7 @@ tui_disasm_window::set_contents (struct gdbarch *arch,
 	   + asm_lines[i].insn);
 
       const char *ptr = line.c_str ();
-      src->line = tui_copy_source_line (&ptr, -1, offset, line_width);
+      src->line = tui_copy_source_line (&ptr, -1, offset, line_width, 0);
 
       src->line_or_addr.loa = LOA_ADDRESS;
       src->line_or_addr.u.addr = asm_lines[i].addr;
diff --git a/gdb/tui/tui-source.c b/gdb/tui/tui-source.c
index 915f9e3..32877d7 100644
--- a/gdb/tui/tui-source.c
+++ b/gdb/tui/tui-source.c
@@ -20,6 +20,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include <math.h>
 #include <ctype.h>
 #include "symtab.h"
 #include "frame.h"
@@ -33,6 +34,7 @@
 #include "tui/tui-data.h"
 #include "tui/tui-io.h"
 #include "tui/tui-stack.h"
+#include "tui/tui-win.h"
 #include "tui/tui-winsource.h"
 #include "tui/tui-source.h"
 #include "gdb_curses.h"
@@ -59,8 +61,10 @@ tui_source_window::set_contents (struct gdbarch *arch,
       nlines = (line_no + (height - 2)) - line_no;
 
       std::string srclines;
+      const std::vector<off_t> *offsets;
       if (!g_source_cache.get_source_lines (s, line_no, line_no + nlines,
-					    &srclines))
+					    &srclines)
+	  || !g_source_cache.get_line_charpos (s, &offsets))
 	ret = TUI_FAILURE;
       else
 	{
@@ -78,6 +82,13 @@ tui_source_window::set_contents (struct gdbarch *arch,
 	  start_line_or_addr.loa = LOA_LINE;
 	  cur_line_no = start_line_or_addr.u.line_no = line_no;
 
+	  int digits = 0;
+	  if (compact_source)
+	    {
+	      double l = log10 (offsets->size ());
+	      digits = 1 + (int) l;
+	    }
+
 	  const char *iter = srclines.c_str ();
 	  content.resize (nlines);
 	  while (cur_line < nlines)
@@ -89,7 +100,7 @@ tui_source_window::set_contents (struct gdbarch *arch,
 	      if (*iter != '\0')
 		text = tui_copy_source_line (&iter, cur_line_no,
 					     horizontal_offset,
-					     line_width);
+					     line_width, digits);
 
 	      /* Set whether element is the execution point
 		 and whether there is a break point on it.  */
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index f47dad8..576f9a5 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -927,6 +927,29 @@ tui_show_tab_width (struct ui_file *file, int from_tty,
 
 }
 
+/* See tui-win.h.  */
+
+bool compact_source = false;
+
+/* Callback for "set tui compact-source".  */
+
+static void
+tui_set_compact_source (const char *ignore, int from_tty,
+			struct cmd_list_element *c)
+{
+  if (TUI_SRC_WIN != nullptr)
+    TUI_SRC_WIN->refill ();
+}
+
+/* Callback for "show tui compact-source".  */
+
+static void
+tui_show_compact_source (struct ui_file *file, int from_tty,
+			 struct cmd_list_element *c, const char *value)
+{
+  printf_filtered (_("TUI source window compactness is %s.\n"), value);
+}
+
 /* Set the tab width of the specified window.  */
 static void
 tui_set_tab_width_command (const char *arg, int from_tty)
@@ -1484,4 +1507,14 @@ When enabled GDB will print a message when the terminal is resized."),
 			   show_tui_resize_message,
 			   &maintenance_set_cmdlist,
 			   &maintenance_show_cmdlist);
+
+  add_setshow_boolean_cmd ("compact-source", class_tui,
+			   &compact_source, _("\
+Set whether the TUI source window is compact."), _("\
+Show whether the TUI source window is compact."), _("\
+This variable controls whether the TUI source window is shown\n\
+in a compact form.  The compact form puts the source closer to\n\
+the line numbers and uses less horizontal space."),
+			   tui_set_compact_source, tui_show_compact_source,
+			   &tui_setlist, &tui_showlist);
 }
diff --git a/gdb/tui/tui-win.h b/gdb/tui/tui-win.h
index 81b7dac..1ffe683 100644
--- a/gdb/tui/tui-win.h
+++ b/gdb/tui/tui-win.h
@@ -54,4 +54,7 @@ extern void tui_update_gdb_sizes (void);
 /* Create or get the TUI command list.  */
 struct cmd_list_element **tui_get_cmd_list (void);
 
+/* Whether compact source display should be used.  */
+extern bool compact_source;
+
 #endif /* TUI_TUI_WIN_H */
diff --git a/gdb/tui/tui-winsource.c b/gdb/tui/tui-winsource.c
index 3ca723c..81937c1 100644
--- a/gdb/tui/tui-winsource.c
+++ b/gdb/tui/tui-winsource.c
@@ -69,7 +69,7 @@ tui_display_main ()
 
 std::string
 tui_copy_source_line (const char **ptr, int line_no, int first_col,
-		      int line_width)
+		      int line_width, int ndigits)
 {
   const char *lineptr = *ptr;
 
@@ -78,10 +78,15 @@ tui_copy_source_line (const char **ptr, int line_no, int first_col,
 
   if (line_no > 0)
     {
-      result = string_printf ("%-6d", line_no);
-      int len = result.size ();
-      len = len - ((len / tui_tab_width) * tui_tab_width);
-      result.append (len, ' ');
+      if (ndigits > 0)
+	result = string_printf ("%*d ", ndigits, line_no);
+      else
+	{
+	  result = string_printf ("%-6d", line_no);
+	  int len = result.size ();
+	  len = len - ((len / tui_tab_width) * tui_tab_width);
+	  result.append (len, ' ');
+	}
     }
 
   int column = 0;
diff --git a/gdb/tui/tui-winsource.h b/gdb/tui/tui-winsource.h
index 7c3c626..8b96200 100644
--- a/gdb/tui/tui-winsource.h
+++ b/gdb/tui/tui-winsource.h
@@ -238,12 +238,16 @@ extern void tui_update_source_windows_with_line (struct symtab *,
 /* Extract some source text from PTR.  LINE_NO is the line number.  If
    it is positive, it is printed at the start of the line.  FIRST_COL
    is the first column to extract, and LINE_WIDTH is the number of
-   characters to display.  Returns a string holding the desired text.
-   PTR is updated to point to the start of the next line.  */
+   characters to display.  NDIGITS is used to format the line number
+   (if it is positive).  If NDIGITS is greater than 0, then that many
+   digits are used; otherwise the line number is formatted with 6
+   digits and the text is aligned to the next tab stop.  Returns a
+   string holding the desired text.  PTR is updated to point to the
+   start of the next line.  */
 
 extern std::string tui_copy_source_line (const char **ptr,
 					 int line_no, int first_col,
-					 int line_width);
+					 int line_width, int ndigits);
 
 /* Constant definitions. */
 #define SCROLL_THRESHOLD 2	/* Threshold for lazy scroll.  */