;;; semantic-dep.el --- Methods for tracking dependencies (include files)

;;; Copyright (C) 2006, 2007 Eric M. Ludlam

;; Author: Eric M. Ludlam <zappo@gnu.org>
;; Keywords: syntax
;; X-RCS: $Id: semantic-dep.el,v 1.4 2007/05/17 01:41:20 zappo Exp $

;; This file is not part of GNU Emacs.

;; Semantic 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 2, or (at your option)
;; any later version.

;; This software 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:
;;
;; Include tags (dependencies for a given source file) usually have
;; some short name.  The target file that it is dependent on is
;; generally found on some sort of path controlled by the compiler or
;; project.
;;
;; EDE or even ECB can control our project dependencies, and help us
;; find file within the setting of a given project.  For system
;; dependencies, we need to depend on user supplied lists, which can
;; manifest themselves in the form of system datatabases (from
;; semanticdb.)
;;
;; Provide ways to track these different files here.

(require 'semantic-tag)

;;; Code:

;;;###autoload
(defvar semantic-dependency-include-path nil
  "Defines the include path used when searching for files.
This should be a list of directories to search which is specific
to the file being included.

If `semantic-dependency-tag-file' is overridden for a given
language, this path is most likely ignored.

The above function, reguardless of being overriden, caches the
located dependency file location in the tag property
`dependency-file'.  If you override this function, you do not
need to implement your own cache.  Each time the buffer is fully
reparsed, the cache will be reset.

TODO: use ffap.el to locate such items?

NOTE: Obsolete this, or use as special user")
(make-variable-buffer-local `semantic-dependency-include-path)

;;;###autoload
(defvar semantic-dependency-system-include-path nil
  "Defines the system include path.
This should be set with either `defvar-mode-local', or with
`semantic-add-system-include'.

When searching for a file associated with a name found in an tag of
class include, this path will be inspected for includes of type
`system'.  Some include tags are agnostic to this setting and will
check both the project and system directories.")
(make-variable-buffer-local `semantic-dependency-include-path)

;;; PATH MANAGEMENT
;;
;; Some fcns to manage paths for a give mode.
;;;###autoload
(defun semantic-add-system-include (dir &optional mode)
  "Add a system include DIR to path for MODE.
Modifies a mode-local version of
`semantic-dependency-system-include-path'."
  (interactive "DDirectory: ")
  (if (not mode) (setq mode major-mode))
  (let ((dirtmp (file-name-as-directory dir))
	(value
	 (mode-local-value mode 'semantic-dependency-system-include-path))
	)
    (add-to-list 'value dirtmp t)
    (eval `(setq-mode-local ,mode
			    semantic-dependency-system-include-path value))
    ))

;;;###autoload
(defun semantic-remove-system-include (dir &optional mode)
  "Add a system include DIR to path for MODE.
Modifies a mode-local version of
`semantic-dependency-system-include-path'."
  (interactive (list
		 (completing-read
		  "Directory to Remove: "
		  semantic-dependency-system-include-path))
	       )
  (if (not mode) (setq mode major-mode))
  (let ((dirtmp (file-name-as-directory dir))
	(value
	 (mode-local-value mode 'semantic-dependency-system-include-path))
	)
    (setq value (delete dirtmp value))
    (eval `(setq-mode-local ,mode semantic-dependency-system-include-path
			    value))
    ))

;;;###autoload
(defun semantic-reset-system-include (&optional mode)
  "Reset the system include list to empty for MODE.
Modifies a mode-local version of
`semantic-dependency-system-include-path'."
  (interactive)
  (if (not mode) (setq mode major-mode))
  (eval `(setq-mode-local ,mode semantic-dependency-system-include-path
			  nil))
  )


;;; PATH SEARCH
;;
;; methods for finding files on a provided path.
(defun semantic--dependency-find-file-on-path (file path)
  "Return an expanded file name for FILE on PATH."
  (let ((p path)
	(found nil))
    (while (and p (not found))
      (let ((f (expand-file-name file (car p))))
	(if (file-exists-p f)
	    (setq found f)))
      (setq p (cdr p)))
    found))

;;;###autoload
(defun semantic-dependency-find-file-on-path (file systemp &optional mode)
  "Return an expanded file name for FILE on available paths.
If SYSTEMP is true, then only search system paths.
If optional argument MODE is non-nil, then derive paths from the
provided mode, not from the current major mode."
  (if (not mode) (setq mode major-mode))
  (let ((sysp (mode-local-value
	       mode 'semantic-dependency-system-include-path))
	(locp (mode-local-value
	       mode 'semantic-dependency-include-path))
	(found nil))
    (when (file-exists-p file)
      (setq found file))
    (when (and (not found) (not systemp))
      (setq found (semantic--dependency-find-file-on-path file locp)))
    (when (not found)
      (setq found (semantic--dependency-find-file-on-path file sysp)))
    (if found (expand-file-name found))))


(provide 'semantic-dep)

;;; semantic-dep.el ends here