New cli-utils.h/.c function extract_info_print_args

New cli-utils.h/.c function extract_info_print_args factorizes
the extraction of the args '[-q] [-t TYPEREGEXP] [NAMEREGEXP]'.
New cli-utils.h/.c function report_unrecognized_option_error
factorizes reporting an unknown option for a command.

These functions will be used by the commands
  info [args|functions|locals|variables]

As extract_info_print_args will be used for 'info functions|variables' which
already have the NAMEREGEXP arg, it provides a backward compatible
behaviour.

cli-utils.c has a new static function extract_arg_maybe_quoted
that extracts an argument, possibly quoted.  The behaviour of this
function is similar to the parsing done by gdb_argv.

gdb/ChangeLog
2018-10-27  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* cli-utils.c (extract_arg_maybe_quoted): New function.
	(extract_info_print_args): New function.
	(info_print_args_help): New function.
	(report_unrecognized_option_error): New function.
	* cli-utils.h (extract_arg_maybe_quoted): New function.
	(extract_info_print_args): New function.
	(info_print_args_help): New function.
	(report_unrecognized_option_error): New function.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2018-10-27  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
+
+	* cli-utils.c (extract_arg_maybe_quoted): New function.
+	(extract_info_print_args): New function.
+	(info_print_args_help): New function.
+	(report_unrecognized_option_error): New function.
+	* cli-utils.h (extract_arg_maybe_quoted): New function.
+	(extract_info_print_args): New function.
+	(info_print_args_help): New function.
+	(report_unrecognized_option_error): New function.
+
 2018-10-26  Tom Tromey  <tom@tromey.com>
 
 	* dwarf2read.c (recursively_compute_inclusions): Use std::vector.

gdb/cli/cli-utils.c

@@ -23,6 +23,8 @@
 
 #include <ctype.h>
 
+static std::string extract_arg_maybe_quoted (const char **arg);
+
 /* See documentation in cli-utils.h.  */
 
 int
@@ -128,6 +130,70 @@ get_number (char **pp)
 
 /* See documentation in cli-utils.h.  */
 
+bool
+extract_info_print_args (const char **args,
+			 bool *quiet,
+			 std::string *regexp,
+			 std::string *t_regexp)
+{
+  /* Check for NAMEREGEXP or -- NAMEREGEXP.  */
+  if (**args != '-' || check_for_argument (args, "--", 2))
+    {
+      *args = skip_spaces (*args);
+      *regexp = *args;
+      *args = NULL;
+      return true;
+    }
+
+  if (check_for_argument (args, "-t", 2))
+    {
+      *t_regexp = extract_arg_maybe_quoted (args);
+      *args = skip_spaces (*args);
+      return true;
+    }
+
+  if (check_for_argument (args, "-q", 2))
+    {
+      *quiet = true;
+      *args = skip_spaces (*args);
+      return true;
+    }
+
+  return false;
+}
+
+/* See documentation in cli-utils.h.  */
+
+void
+report_unrecognized_option_error (const char *command, const char *args)
+{
+  std::string option = extract_arg (&args);
+
+  error (_("Unrecognized option '%s' to %s command.  "
+	   "Try \"help %s\"."), option.c_str (),
+	 command, command);
+}
+
+/* See documentation in cli-utils.h.  */
+
+const char *
+info_print_args_help (const char *prefix,
+		      const char *entity_kind)
+{
+  return xstrprintf (_("\
+%sIf NAMEREGEXP is provided, only prints the %s whose name\n\
+matches NAMEREGEXP.\n\
+If -t TYPEREGEXP is provided, only prints the %s whose type\n\
+matches TYPEREGEXP.  Note that the matching is done with the type\n\
+printed by the 'whatis' command.\n\
+By default, the command might produce headers and/or messages indicating\n\
+why no %s can be printed.\n\
+The flag -q disables the production of these headers and messages."),
+		     prefix, entity_kind, entity_kind, entity_kind);
+}
+
+/* See documentation in cli-utils.h.  */
+
 number_or_range_parser::number_or_range_parser (const char *string)
 {
   init (string);
@@ -283,6 +349,69 @@ remove_trailing_whitespace (const char *start, const char *s)
   return s;
 }
 
+/* A helper function to extract an argument from *ARG.  An argument is
+   delimited by whitespace, but it can also be optionally quoted.
+   The quoting and special characters are handled similarly to
+   the parsing done by gdb_argv.
+   The return value is empty if no argument was found.  */
+
+static std::string
+extract_arg_maybe_quoted (const char **arg)
+{
+  bool squote = false;
+  bool dquote = false;
+  bool bsquote = false;
+  std::string result;
+  const char *p = *arg;
+
+  /* Find the start of the argument.  */
+  p = skip_spaces (p);
+
+  /* Parse p similarly to gdb_argv buildargv function.  */
+  while (*p != '\0')
+    {
+      if (isspace (*p) && !squote && !dquote && !bsquote)
+	  break;
+      else
+	{
+	  if (bsquote)
+	    {
+	      bsquote = false;
+	      result += *p;
+	    }
+	  else if (*p == '\\')
+	      bsquote = true;
+	  else if (squote)
+	    {
+	      if (*p == '\'')
+		  squote = false;
+	      else
+		  result += *p;
+	    }
+	  else if (dquote)
+	    {
+	      if (*p == '"')
+		  dquote = false;
+	      else
+		  result += *p;
+	    }
+	  else
+	    {
+	      if (*p == '\'')
+		  squote = true;
+	      else if (*p == '"')
+		  dquote = true;
+	      else
+		  result += *p;
+	    }
+	  p++;
+	}
+    }
+
+  *arg = p;
+  return result;
+}
+
 /* See documentation in cli-utils.h.  */
 
 std::string

gdb/cli/cli-utils.h

@@ -39,6 +39,36 @@ extern int get_number (const char **);
 
 extern int get_number (char **);
 
+/* Extract from ARGS the arguments [-q] [-t TYPEREGEXP] [--] NAMEREGEXP.
+
+   The caller is responsible to initialize *QUIET to false, *REGEXP
+   and *T_REGEXP to "".
+   extract_info_print_args can then be called iteratively to search
+   for valid arguments, as part of a 'main parsing loop' searching for
+   -q/-t/-- arguments together with other flags and options.
+
+   Returns true and updates *ARGS + one of *QUIET, *REGEXP, *T_REGEXP if
+   it finds a valid argument.
+   Returns false if no valid argument is found at the beginning of ARGS.  */
+
+extern bool extract_info_print_args (const char **args,
+				     bool *quiet,
+				     std::string *regexp,
+				     std::string *t_regexp);
+
+/* Throws an error telling the user that ARGS starts with an option
+   unrecognized by COMMAND.  */
+
+extern void report_unrecognized_option_error (const char *command,
+					      const char *args);
+
+
+/* Builds the help string for a command documented by PREFIX,
+   followed by the extract_info_print_args help for ENTITY_KIND.  */
+
+const char *info_print_args_help (const char *prefix,
+				  const char *entity_kind);
+
 /* Parse a number or a range.
    A number will be of the form handled by get_number.
    A range will be of the form <number1> - <number2>, and