org-attach.el: Get attachments from git annex

* org-attach.el (org-attach-use-annex): New function to check if git
  annex should be used.
  (org-attach-annex-get-maybe): New function to get a file from git
  annex if necessary.
  (org-attach-annex-auto-get): New defcustom to determine behavior
  of org-attach-annex-get-maybe.
  (org-attach-open): Automatically get attached files from git annex when
  opening if necessary.
* testing/lisp/test-org-annex.el: New file for testing org-attach. Only
  contains code for testing org-attach with git annex at the moment.
* mk/targets.mk: Fix cleantest target so it can delete git annex repos.

lisp/org-attach.el

@@ -131,6 +131,17 @@ When set to `query', ask the user instead."
 	  (const :tag "Always delete attachments" t)
 	  (const :tag "Query the user" query)))
 
+(defcustom org-attach-annex-auto-get 'ask
+  "Confirmation preference for automatically getting annex files.
+If \\='ask, prompt using `y-or-n-p'.  If t, always get.  If nil, never get."
+  :group 'org-attach
+  :package-version '(Org . "9")
+  :version "25.1"
+  :type '(choice
+	  (const :tag "confirm with `y-or-n-p'" ask)
+	  (const :tag "always get from annex if necessary" t)
+	  (const :tag "never get from annex" nil)))
+
 ;;;###autoload
 (defun org-attach ()
   "The dispatcher for attachment commands.
@@ -270,29 +281,53 @@ the ATTACH_DIR property) their own attachment directory."
   (org-entry-put nil "ATTACH_DIR_INHERIT" "t")
   (message "Children will inherit attachment directory"))
 
+(defun org-attach-use-annex ()
+  "Return non-nil if git annex can be used."
+  (let ((git-dir (vc-git-root (expand-file-name org-attach-directory))))
+    (and org-attach-git-annex-cutoff
+         (or (file-exists-p (expand-file-name "annex" git-dir))
+             (file-exists-p (expand-file-name ".git/annex" git-dir))))))
+
+(defun org-attach-annex-get-maybe (path)
+  "Call git annex get PATH (via shell) if using git annex.
+Signals an error if the file content is not available and it was not retrieved."
+  (when (and (org-attach-use-annex)
+	     (not
+	      (string-equal
+	       "found"
+	       (shell-command-to-string
+		(format "git annex find --format=found --in=here %s"
+			(shell-quote-argument path))))))
+    (let ((should-get
+	   (if (eq org-attach-annex-auto-get 'ask)
+	       (y-or-n-p (format "Run git annex get %s? " path))
+	     org-attach-annex-auto-get)))
+      (if should-get
+	  (progn (message "Running git annex get \"%s\"." path)
+		 (call-process "git" nil nil nil "annex" "get" path))
+	(error "File %s stored in git annex but it is not available, and was not retrieved"
+	       path)))))
+
 (defun org-attach-commit ()
   "Commit changes to git if `org-attach-directory' is properly initialized.
 This checks for the existence of a \".git\" directory in that directory."
   (let* ((dir (expand-file-name org-attach-directory))
 	 (git-dir (vc-git-root dir))
+	 (use-annex (org-attach-use-annex))
 	 (changes 0))
     (when (and git-dir (executable-find "git"))
       (with-temp-buffer
 	(cd dir)
-	(let ((have-annex
-	       (and org-attach-git-annex-cutoff
-		    (or (file-exists-p (expand-file-name "annex" git-dir))
-			(file-exists-p (expand-file-name ".git/annex" git-dir))))))
-	  (dolist (new-or-modified
-		   (split-string
-		    (shell-command-to-string
-		     "git ls-files -zmo --exclude-standard") "\0" t))
-	    (if (and have-annex
-		     (>= (nth 7 (file-attributes new-or-modified))
-			 org-attach-git-annex-cutoff))
-		(call-process "git" nil nil nil "annex" "add" new-or-modified)
-	      (call-process "git" nil nil nil "add" new-or-modified))
-	    (incf changes)))
+        (dolist (new-or-modified
+                 (split-string
+                  (shell-command-to-string
+                   "git ls-files -zmo --exclude-standard") "\0" t))
+          (if (and use-annex
+                   (>= (nth 7 (file-attributes new-or-modified))
+                       org-attach-git-annex-cutoff))
+              (call-process "git" nil nil nil "annex" "add" new-or-modified)
+            (call-process "git" nil nil nil "add" new-or-modified))
+	    (incf changes))
 	(dolist (deleted
 		 (split-string
 		  (shell-command-to-string "git ls-files -z --deleted") "\0" t))
@@ -465,8 +500,10 @@ If IN-EMACS is non-nil, force opening in Emacs."
 	 (file (if (= (length files) 1)
 		   (car files)
 		 (completing-read "Open attachment: "
-				  (mapcar #'list files) nil t))))
-    (org-open-file (expand-file-name file attach-dir) in-emacs)))
+				  (mapcar #'list files) nil t)))
+         (path (expand-file-name file attach-dir)))
+    (org-attach-annex-get-maybe path)
+    (org-open-file path in-emacs)))
 
 (defun org-attach-open-in-emacs ()
   "Open attachment, force opening in Emacs.

mk/targets.mk

@@ -158,4 +158,6 @@ cleandocs:
 	-$(FIND) doc -name \*~ -exec $(RM) {} \;
 
 cleantest:
+# git annex makes files 444, change to user writable so we can delete them
+	if [ -d $(testdir) ] ; then chmod u+w -R $(testdir) ; fi
 	$(RMR) $(testdir)

testing/lisp/test-org-attach.el

@@ -0,0 +1,97 @@
+;;; test-org-attach.el --- Tests for Org Attach
+;;
+;; Copyright (c) 2016 Erik Hetzner
+;; Authors: Erik Hetzner
+
+;; This file is not part of GNU Emacs.
+
+;; This program 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 3 of the License, or
+;; (at your option) any later version.
+
+;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+(require 'org-attach)
+(require 'cl-lib)
+
+(defmacro test-org-attach-annex/with-annex (&rest body)
+  `(let ((tmpdir (make-temp-file "org-annex-test" t)))
+     (unwind-protect
+	 (let ((default-directory tmpdir)
+	       (org-attach-directory tmpdir))
+	   (shell-command "git init")
+	   (shell-command "git annex init")
+	   ,@body))))
+
+(ert-deftest test-org-attach/use-annex ()
+  (org-test-for-executable "git-annex")
+  (test-org-attach-annex/with-annex
+   (let ((org-attach-git-annex-cutoff 1))
+     (should (org-attach-use-annex)))
+
+   (let ((org-attach-git-annex-cutoff nil))
+     (should-not (org-attach-use-annex))))
+
+  ;; test with non annex directory
+  (let ((tmpdir (make-temp-file "org-annex-test" t)))
+     (unwind-protect
+	 (let ((default-directory tmpdir)
+	       (org-attach-directory tmpdir))
+	   (shell-command "git init")
+	   (should-not (org-attach-use-annex)))
+       (delete-directory tmpdir 'recursive))))
+
+(ert-deftest test-org-attach/get-maybe ()
+  (org-test-for-executable "git-annex")
+  (test-org-attach-annex/with-annex
+   (let ((path (expand-file-name "test-file"))
+	 (annex-dup (make-temp-file "org-annex-test" t)))
+     (with-temp-buffer
+       (insert "hello world\n")
+       (write-file path))
+     (shell-command "git annex add test-file")
+     (shell-command "git annex sync")
+     ;; Set up remote & copy files there
+     (let ((annex-original default-directory)
+	   (default-directory annex-dup))
+       (shell-command (format "git clone %s ." (shell-quote-argument annex-original)))
+       (shell-command "git annex init dup")
+       (shell-command (format "git remote add original %s" (shell-quote-argument annex-original)))
+       (shell-command "git annex get test-file")
+       (shell-command "git annex sync"))
+     (shell-command (format "git remote add dup %s" (shell-quote-argument annex-dup)))
+     (shell-command "git annex sync")
+     (shell-command "git annex drop --force test-file")
+     ;; test getting the file from the dup when we should ALWAYS get
+     (should (not (file-exists-p (file-symlink-p (expand-file-name "test-file")))))
+     (let ((org-attach-annex-auto-get t))
+       (org-attach-annex-get-maybe (expand-file-name "test-file"))
+       ;; check that the file has the right contents
+       (with-temp-buffer
+	 (insert-file-contents path)
+	 (should (string-equal "hello world\n" (buffer-string)))))
+     ;; test getting the file from the dup when we should NEVER get
+     (shell-command "git annex drop --force test-file")
+     (let ((org-attach-annex-auto-get nil))
+       (should-error (org-attach-annex-get-maybe (expand-file-name "test-file"))))
+     (let ((org-attach-annex-auto-get 'ask)
+	   (called nil))
+       (flet ((y-or-n-p (prompt)
+			   (setq called 'was-called)
+			   t))
+	 (org-attach-annex-get-maybe (expand-file-name "test-file"))
+	 ;; check that the file has the right contents
+	 (with-temp-buffer
+	   (insert-file-contents path)
+	   (should (string-equal "hello world\n" (buffer-string))))
+	 (should (eq called 'was-called)))))))
+
+;;; test-org-attach.el ends here