cli-script.c: Simplify using std::string, eliminate cleanups

gdb/ChangeLog:
2016-11-08  Pedro Alves  <palves@redhat.com>

	* cli/cli-script.c (execute_control_command): Use std::string
	instead of cleanups.
	(locate_arg): Constify return type.
	(insert_args): Constify paremeter.  Simplify using std::string.
	Return a std::string.

2 files changed, 41 insertions, 76 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b71248a..8b3efe8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
 2016-11-08  Pedro Alves  <palves@redhat.com>
 
+	* cli/cli-script.c (execute_control_command): Use std::string
+	instead of cleanups.
+	(locate_arg): Constify return type.
+	(insert_args): Constify paremeter.  Simplify using std::string.
+	Return a std::string.
+
+2016-11-08  Pedro Alves  <palves@redhat.com>
+
 	* breakpoint.c (struct commands_info) <arg>: Constify.
 	(commands_command_1): Constify 'arg' parameter.  Use std::string
 	and string_printf.
diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index e5cf20b..7b73832 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -41,7 +41,7 @@ recurse_read_control_structure (char * (*read_next_line_func) (void),
 				void (*validator)(char *, void *),
 				void *closure);
 
-static char *insert_args (char *line);
+static std::string insert_args (const char *line);
 
 static struct cleanup * setup_user_args (char *p);
 
@@ -447,7 +447,6 @@ execute_control_command (struct command_line *cmd)
   struct value *val_mark;
   int loop;
   enum command_control_type ret;
-  char *new_line;
 
   /* Start by assuming failure, if a problem is detected, the code
      below will simply "break" out of the switch.  */
@@ -456,12 +455,13 @@ execute_control_command (struct command_line *cmd)
   switch (cmd->control_type)
     {
     case simple_control:
-      /* A simple command, execute it and return.  */
-      new_line = insert_args (cmd->line);
-      make_cleanup (free_current_contents, &new_line);
-      execute_command (new_line, 0);
-      ret = cmd->control_type;
-      break;
+      {
+	/* A simple command, execute it and return.  */
+	std::string new_line = insert_args (cmd->line);
+	execute_command (&new_line[0], 0);
+	ret = cmd->control_type;
+	break;
+      }
 
     case continue_control:
       print_command_trace ("loop_continue");
@@ -488,9 +488,8 @@ execute_control_command (struct command_line *cmd)
 	print_command_trace (buffer);
 
 	/* Parse the loop control expression for the while statement.  */
-	new_line = insert_args (cmd->line);
-	make_cleanup (free_current_contents, &new_line);
-	expr = parse_expression (new_line);
+	std::string new_line = insert_args (cmd->line);
+	expr = parse_expression (new_line.c_str ());
 	make_cleanup (free_current_contents, &expr);
 
 	ret = simple_control;
@@ -554,10 +553,9 @@ execute_control_command (struct command_line *cmd)
 	xsnprintf (buffer, len, "if %s", cmd->line);
 	print_command_trace (buffer);
 
-	new_line = insert_args (cmd->line);
-	make_cleanup (free_current_contents, &new_line);
 	/* Parse the conditional for the if statement.  */
-	expr = parse_expression (new_line);
+	std::string new_line = insert_args (cmd->line);
+	expr = parse_expression (new_line.c_str ());
 	make_cleanup (free_current_contents, &expr);
 
 	current = NULL;
@@ -597,9 +595,8 @@ execute_control_command (struct command_line *cmd)
       {
 	/* Breakpoint commands list, record the commands in the
 	   breakpoint's command list and return.  */
-	new_line = insert_args (cmd->line);
-	make_cleanup (free_current_contents, &new_line);
-	ret = commands_from_control_command (new_line, cmd);
+	std::string new_line = insert_args (cmd->line);
+	ret = commands_from_control_command (new_line.c_str (), cmd);
 	break;
       }
 
@@ -778,8 +775,8 @@ setup_user_args (char *p)
 /* Given character string P, return a point to the first argument
    ($arg), or NULL if P contains no arguments.  */
 
-static char *
-locate_arg (char *p)
+static const char *
+locate_arg (const char *p)
 {
   while ((p = strchr (p, '$')))
     {
@@ -792,92 +789,52 @@ locate_arg (char *p)
 }
 
 /* Insert the user defined arguments stored in user_arg into the $arg
-   arguments found in line, with the updated copy being placed into
-   nline.  */
+   arguments found in line.  */
 
-static char *
-insert_args (char *line)
+static std::string
+insert_args (const char *line)
 {
-  char *p, *save_line, *new_line;
-  unsigned len, i;
-
   /* If we are not in a user-defined function, treat $argc, $arg0, et
      cetera as normal convenience variables.  */
   if (user_args == NULL)
-    return xstrdup (line);
+    return line;
 
-  /* First we need to know how much memory to allocate for the new
-     line.  */
-  save_line = line;
-  len = 0;
-  while ((p = locate_arg (line)))
-    {
-      len += p - line;
-      i = p[4] - '0';
-
-      if (p[4] == 'c')
-	{
-	  /* $argc.  Number will be <=10.  */
-	  len += user_args->count == 10 ? 2 : 1;
-	}
-      else if (i >= user_args->count)
-	{
-	  error (_("Missing argument %d in user function."), i);
-	}
-      else
-	{
-	  len += user_args->a[i].len;
-	}
-      line = p + 5;
-    }
-
-  /* Don't forget the tail.  */
-  len += strlen (line);
-
-  /* Allocate space for the new line and fill it in.  */
-  new_line = (char *) xmalloc (len + 1);
-
-  /* Restore pointer to beginning of old line.  */
-  line = save_line;
-
-  /* Save pointer to beginning of new line.  */
-  save_line = new_line;
+  std::string new_line;
+  const char *p;
 
   while ((p = locate_arg (line)))
     {
       int i, len;
 
-      memcpy (new_line, line, p - line);
-      new_line += p - line;
+      new_line.append (line, p - line);
 
       if (p[4] == 'c')
 	{
 	  gdb_assert (user_args->count >= 0 && user_args->count <= 10);
 	  if (user_args->count == 10)
 	    {
-	      *(new_line++) = '1';
-	      *(new_line++) = '0';
+	      new_line += '1';
+	      new_line += '0';
 	    }
 	  else
-	    *(new_line++) = user_args->count + '0';
+	    new_line += user_args->count + '0';
 	}
       else
 	{
 	  i = p[4] - '0';
+	  if (i >= user_args->count)
+	    error (_("Missing argument %d in user function."), i);
+
 	  len = user_args->a[i].len;
-	  if (len)
-	    {
-	      memcpy (new_line, user_args->a[i].arg, len);
-	      new_line += len;
-	    }
+	  if (len > 0)
+	    new_line.append (user_args->a[i].arg, len);
 	}
       line = p + 5;
     }
   /* Don't forget the tail.  */
-  strcpy (new_line, line);
+  new_line.append (line);
 
-  /* Return a pointer to the beginning of the new line.  */
-  return save_line;
+  return new_line;
 }