Re: [PATCH 00/16] Add styling to the gdb CLI and TUI

Eli Zaretskii
2019-03-03T15:42:47Z

> From: Tom Tromey <tom@tromey.com>
> Cc: Tom Tromey <tom@tromey.com>, gdb-patches@sourceware.org
> Date: Fri, 01 Mar 2019 14:03:58 -0700
>
> Another way would be to just make a new function and implement it
> differently in mingw-hdep.c and in posix-hdep.c.

Here's a working prototype I'm currently testing. If this
implementation strategy is acceptable, I will post a proper patch
soon.

Thanks for the guidance.

--- ./gdb/cli/cli-style.c~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/cli/cli-style.c 2019-03-03 17:26:34.122234300 +0200
@@ -24,7 +24,7 @@

/* True if styling is enabled. */

-#if defined(_WIN32) || defined (__CYGWIN__)
+#if defined (__MSDOS__) || defined (__CYGWIN__)
int cli_styling = 0;
#else
int cli_styling = 1;
--- ./gdb/mingw-hdep.c~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/mingw-hdep.c 2019-03-03 17:15:24.608418300 +0200
@@ -177,3 +177,166 @@ gdb_select (int n, fd_set *readfds, fd_s

return num_ready;
}
+
+/* Zero if not yet initialized, 1 if stdout is a console device, else -1. */
+static int mingw_console_initialized;
+
+/* Handle to stdout . */
+static HANDLE hstdout = INVALID_HANDLE_VALUE;
+
+/* Text attribute to use for normal text (the "none" pseudo-color). */
+static SHORT norm_attr;
+
+/* The most recently applied style. */
+static ui_file_style last_style;
+
+/* Alternative for the libc 'fputs' which handles embedded SGR
+ sequences in support of styling. */
+
+int
+gdb_console_fputs (const char *linebuf, FILE *fstream)
+{
+ if (!mingw_console_initialized)
+ {
+ hstdout = (HANDLE)_get_osfhandle (fileno (fstream));
+ DWORD cmode;
+ CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+ if (hstdout != INVALID_HANDLE_VALUE
+ && GetConsoleMode (hstdout, &cmode) != 0
+ && GetConsoleScreenBufferInfo (hstdout, &csbi))
+ {
+ norm_attr = csbi.wAttributes;
+ mingw_console_initialized = 1;
+ }
+ else if (hstdout != INVALID_HANDLE_VALUE)
+ mingw_console_initialized = -1; /* valid, but not a console device */
+ }
+ /* If our stdout is not a console device, let the default 'fputs'
+ handle the task. */
+ if (mingw_console_initialized <= 0)
+ return 0;
+
+ /* Mapping between 8 ANSI colors and Windows console attributes. */
+ static int fg_color[] = {
+ 0, /* black */
+ FOREGROUND_RED, /* red */
+ FOREGROUND_GREEN, /* green */
+ FOREGROUND_GREEN | FOREGROUND_RED, /* yellow */
+ FOREGROUND_BLUE, /* blue */
+ FOREGROUND_BLUE | FOREGROUND_RED, /* magenta */
+ FOREGROUND_BLUE | FOREGROUND_GREEN, /* cyan */
+ FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE /* gray */
+ };
+ static int bg_color[] = {
+ 0, /* black */
+ BACKGROUND_RED, /* red */
+ BACKGROUND_GREEN, /* green */
+ BACKGROUND_GREEN | BACKGROUND_RED, /* yellow */
+ BACKGROUND_BLUE, /* blue */
+ BACKGROUND_BLUE | BACKGROUND_RED, /* magenta */
+ BACKGROUND_BLUE | BACKGROUND_GREEN, /* cyan */
+ BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE /* gray */
+ };
+
+ ui_file_style style = last_style;
+ unsigned char c;
+ size_t n_read;
+
+ for ( ; (c = *linebuf) != 0; linebuf += n_read)
+ {
+ if (c == '\033')
+ {
+ fflush (fstream);
+ bool parsed = style.parse (linebuf, &n_read);
+ if (n_read <= 0) /* should never happen */
+ n_read = 1;
+ if (!parsed)
+ {
+ /* This means we silently swallow SGR sequences we
+ cannot parse. */
+ continue;
+ }
+ /* Colors. */
+ const ui_file_style::color &fg = style.get_foreground ();
+ const ui_file_style::color &bg = style.get_background ();
+ int fgcolor, bgcolor, bright, inverse;
+ if (fg.is_none ())
+ fgcolor = norm_attr & 15;
+ else
+ fgcolor = fg_color[fg.get_value () & 15];
+ if (bg.is_none ())
+ bgcolor = norm_attr & (15 << 4);
+ else
+ bgcolor = bg_color[bg.get_value () & 15];
+
+ /* Intensity. */
+ switch (style.get_intensity ())
+ {
+ case ui_file_style::NORMAL:
+ case ui_file_style::DIM:
+ bright = 0;
+ break;
+ case ui_file_style::BOLD:
+ bright = 1;
+ break;
+ default:
+ gdb_assert_not_reached ("invalid intensity");
+ }
+
+ /* Inverse video. */
+ if (style.is_reverse ())
+ inverse = 1;
+ else
+ inverse = 0;
+
+ /* Construct the attribute. */
+ if (inverse)
+ {
+ int t = fgcolor;
+ fgcolor = (bgcolor >> 4);
+ bgcolor = (t << 4);
+ }
+ if (bright)
+ fgcolor |= FOREGROUND_INTENSITY;
+
+ SHORT attr = (bgcolor & (15 << 4)) | (fgcolor & 15);
+
+ /* Apply the attribute. */
+ SetConsoleTextAttribute (hstdout, attr);
+ }
+ else
+ {
+ /* When we are about to write newline, we need to clear to
+ EOL with the normal attribute, to avoid spilling the
+ colors to the next screen line. We assume here that no
+ non-default attribute extends beyond the newline. */
+ if (c == '\n')
+ {
+ DWORD nchars;
+ COORD start_pos;
+ DWORD written;
+ CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+ fflush (fstream);
+ GetConsoleScreenBufferInfo (hstdout, &csbi);
+
+ if (csbi.wAttributes != norm_attr)
+ {
+ start_pos = csbi.dwCursorPosition;
+ nchars = csbi.dwSize.X - start_pos.X;
+
+ FillConsoleOutputAttribute (hstdout, norm_attr, nchars,
+ start_pos, &written);
+ FillConsoleOutputCharacter (hstdout, ' ', nchars,
+ start_pos, &written);
+ }
+ }
+ fputc (c, fstream);
+ n_read = 1;
+ }
+ }
+
+ last_style = style;
+ return 1;
+}
--- ./gdb/posix-hdep.c~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/posix-hdep.c 2019-03-03 17:34:32.870539500 +0200
@@ -30,3 +30,11 @@ gdb_select (int n, fd_set *readfds, fd_s
{
return select (n, readfds, writefds, exceptfds, timeout);
}
+
+/* Host-dependent console fputs method. POSIX platforms always return
+ zero, to use the default C 'fputs'. */
+int
+gdb_console_fputs (const char *buf, FILE *f)
+{
+ return 0;
+}
--- ./gdb/ui-file.c~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/ui-file.c 2019-03-03 17:32:02.526701100 +0200
@@ -236,6 +236,12 @@ stdio_file::write_async_safe (const char
void
stdio_file::puts (const char *linebuffer)
{
+ /* This host-dependent function (with implementations in
+ posix-hdep.c and mingw-hdep.c) is given the opportunity to
+ process the output first in host-dependent way. If it does, it
+ should return non-zero, to avoid calling fputs below. */
+ if (gdb_console_fputs (linebuffer, m_file))
+ return;
/* Calling error crashes when we are called from the exception framework. */
if (fputs (linebuffer, m_file))
{
--- ./gdb/ui-file.h~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/ui-file.h 2019-03-03 17:40:00.605222700 +0200
@@ -101,6 +101,8 @@

extern long ui_file_read (struct ui_file *file, char *buf, long length_buf);

+extern int gdb_console_fputs (const char *, FILE *);
+
/* A std::string-based ui_file. Can be used as a scratch buffer for
collecting output. */

--- ./gdb/utils.c~1 2019-02-27 06:51:50.000000000 +0200
+++ ./gdb/utils.c 2019-03-03 17:39:30.222675900 +0200
@@ -1456,8 +1456,18 @@ can_emit_style_escape (struct ui_file *s
|| !ui_file_isatty (stream))
return false;
const char *term = getenv ("TERM");
+ /* Windows doesn't by default define $TERM, but can support styles
+ regardless. */
+#ifndef _WIN32
if (term == nullptr || !strcmp (term, "dumb"))
return false;
+#else
+ /* But if they do define $TERM, let us behave the same as on Posix
+ platforms, for the benefit of programs which invoke GDB as their
+ back-end. */
+ if (term && !strcmp (term, "dumb"))
+ return false;
+#endif
return true;
}