cli-script.c

这个是LINUX下的GDB调度工具的源码

   loop condition is nonzero.  */

void
while_command (char *arg, int from_tty)
{
  struct command_line *command = NULL;

  control_level = 1;
  command = get_command_line (while_control, arg);

  if (command == NULL)
    return;

  execute_control_command (command);
  free_command_lines (&command);
}

/* "if" command support.  Execute either the true or false arm depending
   on the value of the if conditional.  */

void
if_command (char *arg, int from_tty)
{
  struct command_line *command = NULL;

  control_level = 1;
  command = get_command_line (if_control, arg);

  if (command == NULL)
    return;

  execute_control_command (command);
  free_command_lines (&command);
}

/* Cleanup */
static void
arg_cleanup (void *ignore)
{
  struct user_args *oargs = user_args;
  if (!user_args)
    internal_error (__FILE__, __LINE__,
		    "arg_cleanup called with no user args.\n");

  user_args = user_args->next;
  xfree (oargs);
}

/* Bind the incomming arguments for a user defined command to
   $arg0, $arg1 ... $argMAXUSERARGS.  */

static struct cleanup *
setup_user_args (char *p)
{
  struct user_args *args;
  struct cleanup *old_chain;
  unsigned int arg_count = 0;

  args = (struct user_args *) xmalloc (sizeof (struct user_args));
  memset (args, 0, sizeof (struct user_args));

  args->next = user_args;
  user_args = args;

  old_chain = make_cleanup (arg_cleanup, 0/*ignored*/);

  if (p == NULL)
    return old_chain;

  while (*p)
    {
      char *start_arg;
      int squote = 0;
      int dquote = 0;
      int bsquote = 0;

      if (arg_count >= MAXUSERARGS)
	{
	  error ("user defined function may only have %d arguments.\n",
		 MAXUSERARGS);
	  return old_chain;
	}

      /* Strip whitespace.  */
      while (*p == ' ' || *p == '\t')
	p++;

      /* P now points to an argument.  */
      start_arg = p;
      user_args->a[arg_count].arg = p;

      /* Get to the end of this argument.  */
      while (*p)
	{
	  if (((*p == ' ' || *p == '\t')) && !squote && !dquote && !bsquote)
	    break;
	  else
	    {
	      if (bsquote)
		bsquote = 0;
	      else if (*p == '\\')
		bsquote = 1;
	      else if (squote)
		{
		  if (*p == '\'')
		    squote = 0;
		}
	      else if (dquote)
		{
		  if (*p == '"')
		    dquote = 0;
		}
	      else
		{
		  if (*p == '\'')
		    squote = 1;
		  else if (*p == '"')
		    dquote = 1;
		}
	      p++;
	    }
	}

      user_args->a[arg_count].len = p - start_arg;
      arg_count++;
      user_args->count++;
    }
  return old_chain;
}

/* 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)
{
  while ((p = strchr (p, '$')))
    {
      if (strncmp (p, "$arg", 4) == 0 && isdigit (p[4]))
	return p;
      p++;
    }
  return NULL;
}

/* Insert the user defined arguments stored in user_arg into the $arg
   arguments found in line, with the updated copy being placed into nline.  */

static char *
insert_args (char *line)
{
  char *p, *save_line, *new_line;
  unsigned len, i;

  /* 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 (i >= user_args->count)
	{
	  error ("Missing argument %d in user function.\n", i);
	  return NULL;
	}
      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);
  if (new_line == NULL)
    return NULL;

  /* Restore pointer to beginning of old line.  */
  line = save_line;

  /* Save pointer to beginning of new line.  */
  save_line = new_line;

  while ((p = locate_arg (line)))
    {
      int i, len;

      memcpy (new_line, line, p - line);
      new_line += p - line;
      i = p[4] - '0';

      len = user_args->a[i].len;
      if (len)
	{
	  memcpy (new_line, user_args->a[i].arg, len);
	  new_line += len;
	}
      line = p + 5;
    }
  /* Don't forget the tail.  */
  strcpy (new_line, line);

  /* Return a pointer to the beginning of the new line.  */
  return save_line;
}


/* Expand the body_list of COMMAND so that it can hold NEW_LENGTH
   code bodies.  This is typically used when we encounter an "else"
   clause for an "if" command.  */

static void
realloc_body_list (struct command_line *command, int new_length)
{
  int n;
  struct command_line **body_list;

  n = command->body_count;

  /* Nothing to do?  */
  if (new_length <= n)
    return;

  body_list = (struct command_line **)
    xmalloc (sizeof (struct command_line *) * new_length);

  memcpy (body_list, command->body_list, sizeof (struct command_line *) * n);

  xfree (command->body_list);
  command->body_list = body_list;
  command->body_count = new_length;
}

/* Read one line from the input stream.  If the command is an "else" or
   "end", return such an indication to the caller.  */

static enum misc_command_type
read_next_line (struct command_line **command)
{
  char *p, *p1, *prompt_ptr, control_prompt[256];
  int i = 0;

  if (control_level >= 254)
    error ("Control nesting too deep!\n");

  /* Set a prompt based on the nesting of the control commands.  */
  if (instream == stdin || (instream == 0 && deprecated_readline_hook != NULL))
    {
      for (i = 0; i < control_level; i++)
	control_prompt[i] = ' ';
      control_prompt[i] = '>';
      control_prompt[i + 1] = '\0';
      prompt_ptr = (char *) &control_prompt[0];
    }
  else
    prompt_ptr = NULL;

  p = command_line_input (prompt_ptr, instream == stdin, "commands");

  /* Not sure what to do here.  */
  if (p == NULL)
    return end_command;

  /* Strip leading and trailing whitespace.  */
  while (*p == ' ' || *p == '\t')
    p++;

  p1 = p + strlen (p);
  while (p1 != p && (p1[-1] == ' ' || p1[-1] == '\t'))
    p1--;

  /* Blanks and comments don't really do anything, but we need to
     distinguish them from else, end and other commands which can be
     executed.  */
  if (p1 == p || p[0] == '#')
    return nop_command;

  /* Is this the end of a simple, while, or if control structure?  */
  if (p1 - p == 3 && !strncmp (p, "end", 3))
    return end_command;

  /* Is the else clause of an if control structure?  */
  if (p1 - p == 4 && !strncmp (p, "else", 4))
    return else_command;

  /* Check for while, if, break, continue, etc and build a new command
     line structure for them.  */
  if (p1 - p > 5 && !strncmp (p, "while", 5))
    {
      char *first_arg;
      first_arg = p + 5;
      while (first_arg < p1 && isspace (*first_arg))
        first_arg++;
      *command = build_command_line (while_control, first_arg);
    }
  else if (p1 - p > 2 && !strncmp (p, "if", 2))
    {
      char *first_arg;
      first_arg = p + 2;
      while (first_arg < p1 && isspace (*first_arg))
        first_arg++;
      *command = build_command_line (if_control, first_arg);
    }
  else if (p1 - p == 10 && !strncmp (p, "loop_break", 10))
    {
      *command = (struct command_line *)
	xmalloc (sizeof (struct command_line));
      (*command)->next = NULL;
      (*command)->line = NULL;
      (*command)->control_type = break_control;
      (*command)->body_count = 0;
      (*command)->body_list = NULL;
    }
  else if (p1 - p == 13 && !strncmp (p, "loop_continue", 13))
    {
      *command = (struct command_line *)
	xmalloc (sizeof (struct command_line));
      (*command)->next = NULL;
      (*command)->line = NULL;
      (*command)->control_type = continue_control;
      (*command)->body_count = 0;
      (*command)->body_list = NULL;
    }
  else
    {
      /* A normal command.  */
      *command = (struct command_line *)
	xmalloc (sizeof (struct command_line));
      (*command)->next = NULL;
      (*command)->line = savestring (p, p1 - p);
      (*command)->control_type = simple_control;
      (*command)->body_count = 0;
      (*command)->body_list = NULL;
    }

  /* Nothing special.  */
  return ok_command;
}

/* Recursively read in the control structures and create a command_line 
   structure from them.

   The parent_control parameter is the control structure in which the
   following commands are nested.  */

static enum command_control_type
recurse_read_control_structure (struct command_line *current_cmd)
{
  int current_body, i;
  enum misc_command_type val;
  enum command_control_type ret;
  struct command_line **body_ptr, *child_tail, *next;

  child_tail = NULL;
  current_body = 1;

  /* Sanity checks.  */
  if (current_cmd->control_type == simple_control)
    {
      error ("Recursed on a simple control type\n");
      return invalid_control;
    }

  if (current_body > current_cmd->body_count)
    {
      error ("Allocated body is smaller than this command type needs\n");
      return invalid_control;
    }

  /* Read lines from the input stream and build control structures.  */
  while (1)
    {
      dont_repeat ();

      next = NULL;
      val = read_next_line (&next);

      /* Just skip blanks and comments.  */
      if (val == nop_command)
	continue;

      if (val == end_command)
	{
	  if (current_cmd->control_type == while_control
	      || current_cmd->control_type == if_control)
	    {
	      /* Success reading an entire control structure.  */
	      ret = simple_control;
	      break;
	    }
	  else
	    {
	      ret = invalid_control;
	      break;
	    }
	}

      /* Not the end of a control structure.  */
      if (val == else_command)
	{
	  if (current_cmd->control_type == if_control
	      && current_body == 1)
	    {
	      realloc_body_list (current_cmd, 2);
	      current_body = 2;
	      child_tail = NULL;
	      continue;
	    }
	  else
	    {
	      ret = invalid_control;
	      break;
	    }
	}

      if (child_tail)
	{
	  child_tail->next = next;
	}
      else
	{
	  body_ptr = current_cmd->body_list;
	  for (i = 1; i < current_body; i++)
	    body_ptr++;

	  *body_ptr = next;

	}

      child_tail = next;

      /* If the latest line is another control structure, then recurse
         on it.  */
      if (next->control_type == while_control
	  || next->control_type == if_control)
	{
	  control_level++;