Add output styles to gdb

This adds some output styling to the CLI.

A style is currently a foreground color, a background color, and an
intensity (dim or bold).  (This list could be expanded depending on
terminal capabilities.)

A style can be applied while printing.  For ui-out, this is done by
passing the style constant as an argument.  For low-level cases,
fprintf_styled and fputs_styled are provided.

Users can control the style via a number of new set/show commands.  In
the interest of not typing many nearly-identical documentation
strings, I automated this.  On the down side, this is not very
i18n-friendly.

I've chose some default colors to use.  I think it would be good to
enable this by default, so that when users start the new gdb, they
will see the new feature.

Stylizing is done if TERM is set and is not "dumb".  This could be
improved when the TUI is available by using the curses has_colors
call.  That is, the lowest layer could call this without committing to
using curses everywhere; see my other patch for TUI colorizing.

I considered adding a new "set_style" method to ui_file.  However,
because the implementation had to interact with the pager code, I
didn't take this approach.  But, one idea might be to put the isatty
check there and then have it defer to the lower layers.

gdb/ChangeLog
2018-12-28  Tom Tromey  <tom@tromey.com>

	* utils.h (set_output_style, fprintf_styled)
	(fputs_styled): Declare.
	* utils.c (applied_style, desired_style): New globals.
	(emit_style_escape, set_output_style): New function.
	(prompt_for_continue): Emit style escapes.
	(fputs_maybe_filtered): Likewise.
	(fputs_styled, fprintf_styled): New functions.
	* ui-out.h (enum class ui_out_style_kind): New.
	(class ui_out) <field_string, field_stream, do_field_string>: Add
	style parameter.
	* ui-out.c (ui_out::field_stream, ui_out::field_string): Add style
	parameter.
	* tui/tui-out.h (class tui_ui_out) <do_field_string>: Add style
	parameter.
	* tui/tui-out.c (tui_ui_out::do_field_string): Add style
	parameter.
	(tui_ui_out::do_field_string): Update.
	* tracepoint.c (print_one_static_tracepoint_marker): Style
	output.
	* stack.c (print_frame_info, print_frame): Style output.
	* source.c (print_source_lines_base): Style output.
	* skip.c (info_skip_command): Style output.
	* record-btrace.c (btrace_call_history_src_line): Style output.
	(btrace_call_history): Likewise.
	* python/py-framefilter.c (py_print_frame): Style output.
	* mi/mi-out.h (class mi_ui_out) <do_field_string>: Add style
	parameter.
	* mi/mi-out.c (mi_ui_out::do_table_header)
	(mi_ui_out::do_field_int): Update.
	(mi_ui_out::do_field_string): Update.
	* disasm.c (gdb_pretty_print_disassembler::pretty_print_insn):
	Style output.
	* cli/cli-style.h: New file.
	* cli/cli-style.c: New file.
	* cli-out.h (class cli_ui_out) <do_field_string>: Add style
	parameter.
	* cli-out.c (cli_ui_out::do_table_header)
	(cli_ui_out::do_field_int, cli_ui_out::do_field_skip): Update.
	(cli_ui_out::do_field_string): Add style parameter.  Style the
	output.
	* breakpoint.c (print_breakpoint_location): Style output.
	(update_static_tracepoint): Likewise.
	* Makefile.in (SUBDIR_CLI_SRCS): Add cli-style.c.
	(HFILES_NO_SRCDIR): Add cli-style.h.

gdb/testsuite/ChangeLog
2018-12-28  Tom Tromey  <tom@tromey.com>

	* gdb.base/style.exp: New file.
	* gdb.base/style.c: New file.

2 files changed, 346 insertions, 0 deletions

diff --git a/gdb/cli/cli-style.c b/gdb/cli/cli-style.c
new file mode 100644
index 0000000..9f16824
--- /dev/null
+++ b/gdb/cli/cli-style.c
@@ -0,0 +1,257 @@
+/* CLI colorizing
+
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "cli/cli-cmds.h"
+#include "cli/cli-style.h"
+
+/* True if styling is enabled.  */
+
+#if defined(_WIN32) || defined (__CYGWIN__)
+int cli_styling = 0;
+#else
+int cli_styling = 1;
+#endif
+
+/* Name of colors; must correspond to ui_file_style::basic_color.  */
+static const char * const cli_colors[] = {
+  "none",
+  "black",
+  "red",
+  "green",
+  "yellow",
+  "blue",
+  "magenta",
+  "cyan",
+  "white",
+  nullptr
+};
+
+/* Names of intensities; must correspond to
+   ui_file_style::intensity.  */
+static const char * const cli_intensities[] = {
+  "normal",
+  "bold",
+  "dim",
+  nullptr
+};
+
+/* See cli-style.h.  */
+
+cli_style_option file_name_style (ui_file_style::GREEN);
+
+/* See cli-style.h.  */
+
+cli_style_option function_name_style (ui_file_style::YELLOW);
+
+/* See cli-style.h.  */
+
+cli_style_option::cli_style_option (ui_file_style::basic_color fg)
+  : m_foreground (cli_colors[fg - ui_file_style::NONE]),
+    m_background (cli_colors[0]),
+    m_intensity (cli_intensities[ui_file_style::NORMAL])
+{
+}
+
+/* Return the color number corresponding to COLOR.  */
+
+static int
+color_number (const char *color)
+{
+  for (int i = 0; i < ARRAY_SIZE (cli_colors); ++i)
+    {
+      if (color == cli_colors[i])
+	return i - 1;
+    }
+  gdb_assert_not_reached ("color not found");
+}
+
+/* See cli-style.h.  */
+
+ui_file_style
+cli_style_option::style () const
+{
+  int fg = color_number (m_foreground);
+  int bg = color_number (m_background);
+  ui_file_style::intensity intensity = ui_file_style::NORMAL;
+
+  for (int i = 0; i < ARRAY_SIZE (cli_intensities); ++i)
+    {
+      if (m_intensity == cli_intensities[i])
+	{
+	  intensity = (ui_file_style::intensity) i;
+	  break;
+	}
+    }
+
+  return ui_file_style (fg, bg, intensity);
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::do_set (const char *args, int from_tty)
+{
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::do_show (const char *args, int from_tty)
+{
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::do_show_foreground (struct ui_file *file, int from_tty,
+				      struct cmd_list_element *cmd,
+				      const char *value)
+{
+  const char *name = (const char *) get_cmd_context (cmd);
+  fprintf_filtered (file, _("The \"%s\" foreground color is: %s\n"),
+		    name, value);
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::do_show_background (struct ui_file *file, int from_tty,
+				      struct cmd_list_element *cmd,
+				      const char *value)
+{
+  const char *name = (const char *) get_cmd_context (cmd);
+  fprintf_filtered (file, _("The \"%s\" background color is: %s\n"),
+		    name, value);
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::do_show_intensity (struct ui_file *file, int from_tty,
+				     struct cmd_list_element *cmd,
+				     const char *value)
+{
+  const char *name = (const char *) get_cmd_context (cmd);
+  fprintf_filtered (file, _("The \"%s\" display intensity is: %s\n"),
+		    name, value);
+}
+
+/* See cli-style.h.  */
+
+void
+cli_style_option::add_setshow_commands (const char *name,
+					enum command_class theclass,
+					const char *prefix_doc,
+					const char *prefixname,
+					struct cmd_list_element **set_list,
+					struct cmd_list_element **show_list)
+{
+  m_show_prefix = std::string ("set ") + prefixname + " ";
+  m_show_prefix = std::string ("show ") + prefixname + " ";
+
+  add_prefix_cmd (name, no_class, do_set, prefix_doc, &m_set_list,
+		  m_show_prefix.c_str (), 0, set_list);
+  add_prefix_cmd (name, no_class, do_show, prefix_doc, &m_show_list,
+		  m_set_prefix.c_str (), 0, show_list);
+
+  add_setshow_enum_cmd ("foreground", theclass, cli_colors,
+			&m_foreground,
+			_("Set the foreground color for this property"),
+			_("Show the foreground color for this property"),
+			nullptr,
+			nullptr,
+			do_show_foreground,
+			&m_set_list, &m_show_list, (void *) name);
+  add_setshow_enum_cmd ("background", theclass, cli_colors,
+			&m_background,
+			_("Set the background color for this property"),
+			_("Show the background color for this property"),
+			nullptr,
+			nullptr,
+			do_show_background,
+			&m_set_list, &m_show_list, (void *) name);
+  add_setshow_enum_cmd ("intensity", theclass, cli_intensities,
+			&m_intensity,
+			_("Set the display intensity color for this property"),
+			_("\
+Show the display intensity color for this property"),
+			nullptr,
+			nullptr,
+			do_show_intensity,
+			&m_set_list, &m_show_list, (void *) name);
+}
+
+static void
+set_style (const char *arg, int from_tty)
+{
+}
+
+static void
+show_style (const char *arg, int from_tty)
+{
+}
+
+static void
+show_style_enabled (struct ui_file *file, int from_tty,
+		    struct cmd_list_element *c, const char *value)
+{
+  if (cli_styling)
+    fprintf_filtered (file, _("CLI output styling is enabled.\n"));
+  else
+    fprintf_filtered (file, _("CLI output styling is disabled.\n"));
+}
+
+void
+_initialize_cli_style ()
+{
+  static cmd_list_element *style_set_list;
+  static cmd_list_element *style_show_list;
+
+  add_prefix_cmd ("style", no_class, set_style, _("\
+Style-specific settings\n\
+Configure various style-related variables, such as colors"),
+		  &style_set_list, "set style ", 0, &setlist);
+  add_prefix_cmd ("style", no_class, show_style, _("\
+Style-specific settings\n\
+Configure various style-related variables, such as colors"),
+		  &style_show_list, "show style ", 0, &showlist);
+
+  add_setshow_boolean_cmd ("enabled", no_class, &cli_styling, _("\
+Set whether CLI styling is enabled."), _("\
+Show whether CLI is enabled."), _("\
+If enabled, output to the terminal is styled."),
+			   NULL, show_style_enabled,
+			   &style_set_list, &style_show_list);
+
+  file_name_style.add_setshow_commands ("filename", no_class,
+					_("\
+Filename display styling\n\
+Configure filename colors and display intensity."),
+					"style filename",
+					&style_set_list,
+					&style_show_list);
+  function_name_style.add_setshow_commands ("function", no_class,
+					    _("\
+Function name display styling\n\
+Configure function name colors and display intensity"),
+					    "style function",
+					    &style_set_list,
+					    &style_show_list);
+}
diff --git a/gdb/cli/cli-style.h b/gdb/cli/cli-style.h
new file mode 100644
index 0000000..7d5370c
--- /dev/null
+++ b/gdb/cli/cli-style.h
@@ -0,0 +1,89 @@
+/* CLI stylizing
+
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef CLI_STYLE_H
+#define CLI_STYLE_H
+
+#include "ui-file.h"
+
+/* A single CLI style option.  */
+class cli_style_option
+{
+public:
+
+  /* Construct a CLI style option with a foreground color.  */
+  cli_style_option (ui_file_style::basic_color fg);
+
+  /* Return a ui_file_style corresponding to the settings in this CLI
+     style.  */
+  ui_file_style style () const;
+
+  /* Call once to register this CLI style with the CLI engine.  */
+  void add_setshow_commands (const char *name,
+			     enum command_class theclass,
+			     const char *prefix_doc,
+			     const char *prefixname,
+			     struct cmd_list_element **set_list,
+			     struct cmd_list_element **show_list);
+
+private:
+
+  /* The foreground.  */
+  const char *m_foreground;
+  /* The background.  */
+  const char *m_background;
+  /* The intensity.  */
+  const char *m_intensity;
+
+  /* Storage for prefixes needed when registering the commands.  */
+  std::string m_show_prefix;
+  std::string m_set_prefix;
+  /* Storage for command lists needed when registering
+     subcommands.  */
+  struct cmd_list_element *m_set_list = nullptr;
+  struct cmd_list_element *m_show_list = nullptr;
+
+  /* Callback to set a value.  */
+  static void do_set (const char *args, int from_tty);
+  /* Callback to show a value.  */
+  static void do_show (const char *args, int from_tty);
+  /* Callback to show the foreground.  */
+  static void do_show_foreground (struct ui_file *file, int from_tty,
+				  struct cmd_list_element *cmd,
+				  const char *value);
+  /* Callback to show the background.  */
+  static void do_show_background (struct ui_file *file, int from_tty,
+				  struct cmd_list_element *cmd,
+				  const char *value);
+  /* Callback to show the intensity.  */
+  static void do_show_intensity (struct ui_file *file, int from_tty,
+				 struct cmd_list_element *cmd,
+				 const char *value);
+};
+
+/* The file name style.  */
+extern cli_style_option file_name_style;
+
+/* The function name style.  */
+extern cli_style_option function_name_style;
+
+/* True if styling is enabled.  */
+extern int cli_styling;
+
+#endif /* CLI_STYLE_H */