From 41155280f86a3048d4d09dba83d560436d18f9a9 Mon Sep 17 00:00:00 2001
From: Arun Isaac
Date: Mon, 20 Feb 2017 13:58:40 +0530
Subject: Support read/write of multiple tags

* el-exiftool.el (el-exiftool-read): Support reading multiple tags.
(el-exiftool-write): Support writing multiple tags.
* el-exiftool-tests.el (read-write-test): Accommodate new function prototypes.
---
 el-exiftool-tests.el |  9 ++++-----
 el-exiftool.el       | 30 ++++++++++++++++++++++--------
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/el-exiftool-tests.el b/el-exiftool-tests.el
index dd6380c..0dd0cc6 100644
--- a/el-exiftool-tests.el
+++ b/el-exiftool-tests.el
@@ -20,10 +20,9 @@
   (let ((test-filename "test1.png"))
     (let ((temp-filename (make-temp-file "el-exiftool-"
 					 nil (concat "-" test-filename)))
-	  (tag "xmp:Marked")
-	  (value "True"))
+	  (tag-value-alist '(("Marked" . "True"))))
       (copy-file test-filename temp-filename t)
-      (el-exiftool-write temp-filename (cons tag value))
-      (should (equal (el-exiftool-read temp-filename tag)
-		     value))
+      (apply 'el-exiftool-write temp-filename tag-value-alist)
+      (should (equal (el-exiftool-read temp-filename (caar tag-value-alist))
+		     tag-value-alist))
       (delete-file temp-filename))))
diff --git a/el-exiftool.el b/el-exiftool.el
index 61d7630..2e62dfd 100644
--- a/el-exiftool.el
+++ b/el-exiftool.el
@@ -15,6 +15,7 @@
 ;; You should have received a copy of the GNU General Public License
 ;; along with el-exiftool.  If not, see <http://www.gnu.org/licenses/>.
 
+(require 'subr)
 (require 'subr-x)
 (require 'cl)
 
@@ -41,9 +42,17 @@
 			   "\n-execute\n")
 		suffix))))))
 
-(defun el-exiftool-read (filepath tag)
-  (el-exiftool-command
-   "-s" "-s" "-s" (format "-%s" tag) filepath))
+(defun el-exiftool-read (filepath &rest tags)
+  (mapcar
+   (lambda (line)
+     (apply 'cons (split-string line ": ")))
+   (split-string
+    (apply 'el-exiftool-command
+	   "-s" "-s"
+	   (append
+	    (mapcar (apply-partially 'format "-%s") tags)
+	    (list filepath)))
+    "\n+")))
 
 (defun el-exiftool-copy (source destination)
   (el-exiftool-command "-overwrite_original"
@@ -52,10 +61,15 @@
   (message "Tags from %s copied to %s" source destination)
   destination)
 
-(cl-defun el-exiftool-write (filepath (tag . value))
-  (unless (string-blank-p value)
-    (el-exiftool-command
-     "-m" "-overwrite_original"
-     (format "-%s=%s" tag value) filepath)))
+(defun el-exiftool-write (filepath &rest tag-value-alist)
+  (apply 'el-exiftool-command
+	 "-m" "-overwrite_original"
+	 (append
+	  (mapcar
+	   (cl-function
+	    (lambda ((tag . value))
+	      (format "-%s=%s" tag value)))
+	   tag-value-alist)
+	  (list filepath))))
 
 (provide 'el-exiftool)
-- 
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