[binutils-gdb/gdb-8.3-branch] Fix colors in TUI mode in MS-Windows build with ncurses

[Eli Zaretskii <eliz at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=7cf3f4acfddebe44f80b71dcdf1041d870c6d100

commit 7cf3f4acfddebe44f80b71dcdf1041d870c6d100
Author: Eli Zaretskii <eliz@gnu.org>
Date:   Thu Mar 14 17:31:38 2019 +0200

    Fix colors in TUI mode in MS-Windows build with ncurses
    
    The MS-Windows port of ncurses fails to switch to a color pair if
    one or both of the colors are the implicit default colors.  This
    change records the default colors when TUI is initialized, and
    then specifies them explicitly when a color pair uses the default
    colors.  This allows color styling in TUI mode on MS-Windows.
    
    gdb/ChangeLog:
    2019-03-14  Eli Zaretskii  <eliz@gnu.org>
    
    	* tui/tui-io.c [__MINGW32__]: Include windows.h.  Declare
    	ncurses_norm_attr.
    	(tui_initialize_io) [__MINGW32__]: Record the default terminal
    	colors in ncurses_norm_attr.
    	(apply_ansi_escape) [__MINGW32__]: If a color in a color pair is
    	"none", replace it with the default color recorded in
    	ncurses_norm_attr.
    
    (cherry picked from commit 3fff2c370cd658877be8107bfe9dde8dd0470b46)

Diff:
---
 gdb/ChangeLog    | 16 ++++++++++++++++
 gdb/tui/tui-io.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2315067..4243a07 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,19 @@
+2019-03-14  Eli Zaretskii  <eliz@gnu.org>
+
+	The MS-Windows port of ncurses fails to switch to a color pair if
+	one or both of the colors are the implicit default colors.  This
+	change records the default colors when TUI is initialized, and
+	then specifies them explicitly when a color pair uses the default
+	colors.  This allows color styling in TUI mode on MS-Windows.
+
+	* tui/tui-io.c [__MINGW32__]: Include windows.h.  Declare
+	ncurses_norm_attr.
+	(tui_initialize_io) [__MINGW32__]: Record the default terminal
+	colors in ncurses_norm_attr.
+	(apply_ansi_escape) [__MINGW32__]: If a color in a color pair is
+	"none", replace it with the default color recorded in
+	ncurses_norm_attr.
+
 2019-03-14  Tom Tromey  <tromey@adacore.com>
 
 	* source-cache.h (class source_cache) <get_source_lines>: Return
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index d006e41..ef1e885 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -37,6 +37,9 @@
 #include "cli-out.h"
 #include <fcntl.h>
 #include <signal.h>
+#ifdef __MINGW32__
+#include <windows.h>
+#endif
 #include "common/filestuff.h"
 #include "completer.h"
 #include "gdb_curses.h"
@@ -47,6 +50,10 @@
    "gdb_curses.h".  */
 #include "readline/readline.h"
 
+#ifdef __MINGW32__
+static SHORT ncurses_norm_attr;
+#endif
+
 static int tui_getc (FILE *fp);
 
 static int
@@ -322,6 +329,16 @@ apply_ansi_escape (WINDOW *w, const char *buf)
       int fgi, bgi;
       if (get_color (fg, &fgi) && get_color (bg, &bgi))
 	{
+#ifdef __MINGW32__
+	  /* MS-Windows port of ncurses doesn't support implicit
+	     default foreground and background colors, so we must
+	     specify them explicitly when needed, using the colors we
+	     saw at startup.  */
+	  if (fgi == -1)
+	    fgi = ncurses_norm_attr & 15;
+	  if (bgi == -1)
+	    bgi = (ncurses_norm_attr >> 4) & 15;
+#endif
 	  int pair = get_color_pair (fgi, bgi);
 	  if (last_color_pair != -1)
 	    wattroff (w, COLOR_PAIR (last_color_pair));
@@ -807,6 +824,19 @@ tui_initialize_io (void)
 #else
   tui_rl_outstream = stdout;
 #endif
+
+#ifdef __MINGW32__
+  /* MS-Windows port of ncurses doesn't support default foreground and
+     background colors, so we must record the default colors at startup.  */
+  HANDLE hstdout = (HANDLE)_get_osfhandle (fileno (stdout));
+  DWORD cmode;
+  CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+  if (hstdout != INVALID_HANDLE_VALUE
+      && GetConsoleMode (hstdout, &cmode) != 0
+      && GetConsoleScreenBufferInfo (hstdout, &csbi))
+    ncurses_norm_attr = csbi.wAttributes;
+#endif
 }
 
 /* Get a character from the command window.  This is called from the