Add highlight style, title style, fputs_highlighted. Improve 'show style'

Have 'show style' and its subcommands using a style to style its output.
This allows the GDB user or developer to use 'show style' to visually see
with one command how all the current styles look like.

Add 2 new styles highlight style, title style and fputs_highlighted function.

Highlight style is used by fputs_highlighted to highlight the parts of
its char *STR argument that match a HIGHLIGHT regexp.
This (and the title style) will be used in a following patch.

2 files changed, 104 insertions, 34 deletions

diff --git a/gdb/cli/cli-style.c b/gdb/cli/cli-style.c
index f6f6c7b..fb6486b 100644
--- a/gdb/cli/cli-style.c
+++ b/gdb/cli/cli-style.c
@@ -61,29 +61,50 @@ static const char * const cli_intensities[] = {
 
 /* See cli-style.h.  */
 
-cli_style_option file_name_style (ui_file_style::GREEN);
+cli_style_option file_name_style ("filename", ui_file_style::GREEN);
 
 /* See cli-style.h.  */
 
-cli_style_option function_name_style (ui_file_style::YELLOW);
+cli_style_option function_name_style ("function", ui_file_style::YELLOW);
 
 /* See cli-style.h.  */
 
-cli_style_option variable_name_style (ui_file_style::CYAN);
+cli_style_option variable_name_style ("variable", ui_file_style::CYAN);
 
 /* See cli-style.h.  */
 
-cli_style_option address_style (ui_file_style::BLUE);
+cli_style_option address_style ("address", ui_file_style::BLUE);
 
 /* 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]),
+cli_style_option highlight_style ("highlight", ui_file_style::RED);
+
+/* See cli-style.h.  */
+
+cli_style_option title_style ("title", ui_file_style::BOLD);
+
+/* See cli-style.h.  */
+
+cli_style_option::cli_style_option (const char *name,
+				    ui_file_style::basic_color fg)
+  : m_name (name),
+    m_foreground (cli_colors[fg - ui_file_style::NONE]),
     m_background (cli_colors[0]),
     m_intensity (cli_intensities[ui_file_style::NORMAL])
 {
 }
 
+/* See cli-style.h.  */
+
+cli_style_option::cli_style_option (const char *name,
+				    ui_file_style::intensity i)
+  : m_name (name),
+    m_foreground (cli_colors[0]),
+    m_background (cli_colors[0]),
+    m_intensity (cli_intensities[i])
+{
+}
+
 /* Return the color number corresponding to COLOR.  */
 
 static int
@@ -118,6 +139,21 @@ cli_style_option::style () const
   return ui_file_style (fg, bg, intensity);
 }
 
+/* Implements the cli_style_option::do_show_* functions.
+   WHAT and VALUE are the property and value to show.
+   The style for which WHAT is shown is retrieved from CMD context.  */
+
+static void
+do_show (const char *what, struct ui_file *file,
+	 struct cmd_list_element *cmd,
+	 const char *value)
+{
+  cli_style_option *cso = (cli_style_option *) get_cmd_context (cmd);
+  fputs_filtered (_("The "), file);
+  fprintf_styled (file, cso->style (), _("\"%s\" style"), cso->name ());
+  fprintf_filtered (file, _(" %s is: %s\n"), what, value);
+}
+
 /* See cli-style.h.  */
 
 void
@@ -125,9 +161,7 @@ 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);
+  do_show (_("foreground color"), file, cmd, value);
 }
 
 /* See cli-style.h.  */
@@ -137,9 +171,7 @@ 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);
+  do_show (_("background color"), file, cmd, value);
 }
 
 /* See cli-style.h.  */
@@ -149,16 +181,13 @@ 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);
+  do_show (_("display intensity"), file, cmd, value);
 }
 
 /* See cli-style.h.  */
 
 void
-cli_style_option::add_setshow_commands (const char *name,
-					enum command_class theclass,
+cli_style_option::add_setshow_commands (enum command_class theclass,
 					const char *prefix_doc,
 					struct cmd_list_element **set_list,
 					void (*do_set) (const char *args,
@@ -167,12 +196,12 @@ cli_style_option::add_setshow_commands (const char *name,
 					void (*do_show) (const char *args,
 							 int from_tty))
 {
-  m_set_prefix = std::string ("set style ") + name + " ";
-  m_show_prefix = std::string ("show style ") + name + " ";
+  m_set_prefix = std::string ("set style ") + m_name + " ";
+  m_show_prefix = std::string ("show style ") + m_name + " ";
 
-  add_prefix_cmd (name, no_class, do_set, prefix_doc, &m_set_list,
+  add_prefix_cmd (m_name, no_class, do_set, prefix_doc, &m_set_list,
 		  m_set_prefix.c_str (), 0, set_list);
-  add_prefix_cmd (name, no_class, do_show, prefix_doc, &m_show_list,
+  add_prefix_cmd (m_name, no_class, do_show, prefix_doc, &m_show_list,
 		  m_show_prefix.c_str (), 0, show_list);
 
   add_setshow_enum_cmd ("foreground", theclass, cli_colors,
@@ -182,7 +211,7 @@ cli_style_option::add_setshow_commands (const char *name,
 			nullptr,
 			nullptr,
 			do_show_foreground,
-			&m_set_list, &m_show_list, (void *) name);
+			&m_set_list, &m_show_list, (void *) this);
   add_setshow_enum_cmd ("background", theclass, cli_colors,
 			&m_background,
 			_("Set the background color for this property"),
@@ -190,7 +219,7 @@ cli_style_option::add_setshow_commands (const char *name,
 			nullptr,
 			nullptr,
 			do_show_background,
-			&m_set_list, &m_show_list, (void *) name);
+			&m_set_list, &m_show_list, (void *) this);
   add_setshow_enum_cmd ("intensity", theclass, cli_intensities,
 			&m_intensity,
 			_("Set the display intensity for this property"),
@@ -198,7 +227,7 @@ cli_style_option::add_setshow_commands (const char *name,
 			nullptr,
 			nullptr,
 			do_show_intensity,
-			&m_set_list, &m_show_list, (void *) name);
+			&m_set_list, &m_show_list, (void *) this);
 }
 
 static cmd_list_element *style_set_list;
@@ -245,6 +274,18 @@ show_style_sources (struct ui_file *file, int from_tty,
     fprintf_filtered (file, _("Source code styling is disabled.\n"));
 }
 
+/* Builds the "set style NAME " prefix.  */
+
+static std::string
+set_style_name (const char *name)
+{
+  std::string result ("set style ");
+
+  result += name;
+  result += " ";
+  return result;
+}
+
 void
 _initialize_cli_style ()
 {
@@ -278,14 +319,14 @@ it was not linked against GNU Source Highlight."
 			   ), set_style_enabled, show_style_sources,
 			   &style_set_list, &style_show_list);
 
-#define STYLE_ADD_SETSHOW_COMMANDS(STYLE, NAME, PREFIX_DOC)	  \
-  STYLE.add_setshow_commands (NAME, no_class, PREFIX_DOC,		\
+#define STYLE_ADD_SETSHOW_COMMANDS(STYLE, PREFIX_DOC)	  \
+  STYLE.add_setshow_commands (no_class, PREFIX_DOC,		\
 			      &style_set_list,				\
 			      [] (const char *args, int from_tty)	\
 			      {						\
 				help_list				\
 				  (STYLE.set_list (),			\
-				   "set style " NAME " ",		\
+				   set_style_name (STYLE.name ()).c_str (), \
 				   all_commands,			\
 				   gdb_stdout);				\
 			      },					\
@@ -298,23 +339,37 @@ it was not linked against GNU Source Highlight."
 				   "");					\
 			      })
 
-  STYLE_ADD_SETSHOW_COMMANDS (file_name_style, "filename",
+  STYLE_ADD_SETSHOW_COMMANDS (file_name_style,
 			      _("\
 Filename display styling\n\
 Configure filename colors and display intensity."));
 
-  STYLE_ADD_SETSHOW_COMMANDS (function_name_style, "function",
+  STYLE_ADD_SETSHOW_COMMANDS (function_name_style,
 			      _("\
 Function name display styling\n\
 Configure function name colors and display intensity"));
 
-  STYLE_ADD_SETSHOW_COMMANDS (variable_name_style, "variable",
+  STYLE_ADD_SETSHOW_COMMANDS (variable_name_style,
 			      _("\
 Variable name display styling\n\
 Configure variable name colors and display intensity"));
 
-  STYLE_ADD_SETSHOW_COMMANDS (address_style, "address",
+  STYLE_ADD_SETSHOW_COMMANDS (address_style,
 			      _("\
 Address display styling\n\
 Configure address colors and display intensity"));
+
+  STYLE_ADD_SETSHOW_COMMANDS (title_style,
+			      _("\
+Title display styling\n\
+Configure title colors and display intensity\n\
+Some commands (such as \"apropos -v REGEXP\") use the title style to improve\n\
+readability."));
+
+  STYLE_ADD_SETSHOW_COMMANDS (highlight_style,
+			      _("\
+Highlight display styling\n\
+Configure highlight colors and display intensity\n\
+Some commands use the highlight style to draw the attention to a part\n\
+of their output."));
 }
diff --git a/gdb/cli/cli-style.h b/gdb/cli/cli-style.h
index c0520f9..6ae265e 100644
--- a/gdb/cli/cli-style.h
+++ b/gdb/cli/cli-style.h
@@ -28,15 +28,20 @@ class cli_style_option
 public:
 
   /* Construct a CLI style option with a foreground color.  */
-  cli_style_option (ui_file_style::basic_color fg);
+  cli_style_option (const char *name, ui_file_style::basic_color fg);
+
+  /* Construct a CLI style option with an intensity.  */
+  cli_style_option (const char *name, ui_file_style::intensity i);
 
   /* Return a ui_file_style corresponding to the settings in this CLI
      style.  */
   ui_file_style style () const;
 
+  /* Return the style name.  */
+  const char *name () { return m_name; };
+
   /* Call once to register this CLI style with the CLI engine.  */
-  void add_setshow_commands (const char *name,
-			     enum command_class theclass,
+  void add_setshow_commands (enum command_class theclass,
 			     const char *prefix_doc,
 			     struct cmd_list_element **set_list,
 			     void (*do_set) (const char *args, int from_tty),
@@ -52,6 +57,9 @@ public:
 
 private:
 
+  /* The style name.  */
+  const char *m_name;
+
   /* The foreground.  */
   const char *m_foreground;
   /* The background.  */
@@ -93,6 +101,13 @@ extern cli_style_option variable_name_style;
 /* The address style.  */
 extern cli_style_option address_style;
 
+/* The highlight style.  */
+extern cli_style_option highlight_style;
+
+/* The title style.  */
+extern cli_style_option title_style;
+
+
 /* True if source styling is enabled.  */
 extern int source_styling;