Use Python scripts for better portability

Makefile

@@ -111,19 +111,10 @@ youtube-dl.tar.gz: youtube-dl README.md README.txt youtube-dl.1 youtube-dl.bash-
 		youtube-dl
 
 update-po: po/youtube_dl.pot
-	for file in po/*.po ; do \
-		lang=$$(echo $$file | sed -e 's#.*/\([^/]\+\).po#\1#') ; \
-		mv $$file $$file.old ; \
-		msgmerge -N $$file.old po/youtube_dl.pot > $$file ; \
-	done
+	$(PYTHON) devscripts/i18n.py update-po
 
 po/youtube_dl.pot: youtube_dl/*.py youtube_dl/*/*.py
-	touch po/youtube_dl.pot && \
-		xgettext -d youtube_dl -j -k -kg --from-code=utf-8 -o $@ youtube_dl/*.py youtube_dl/*/*.py
+	$(PYTHON) devscripts/i18n.py update-pot
 
 update-gmo:
-	for file in po/*.po ; do \
-		lang=$$(echo $$file | sed -e 's#.*/\([^/]\+\).po#\1#') ; \
-		install -d share/locale/$$lang/LC_MESSAGES; \
-		msgfmt -o share/locale/$$lang/LC_MESSAGES/youtube_dl.mo $$file; \
-	done
+	$(PYTHON) devscripts/i18n.py update-gmo

devscripts/i18n.py

@@ -0,0 +1,79 @@
+import errno
+import glob
+import os
+import subprocess
+import sys
+
+
+def mkdir_p(path):
+    try:
+        os.makedirs(path)
+    except OSError as e:
+        if e.errno == errno.EEXIST and os.path.isdir(path):
+            pass
+        else:
+            raise
+
+
+class I18N_Utils(object):
+    GETTEXT_DOMAIN = 'youtube_dl'
+
+    def get_po_root(self):
+        return 'po/'
+
+    def get_pot_filename(self):
+        return os.path.join(self.get_po_root(), '%s.pot' % self.GETTEXT_DOMAIN)
+
+    @staticmethod
+    def _run_subprocess(cmds):
+        print(' '.join(cmds))
+        subprocess.check_call(cmds)
+
+    def update_gmo_internal(self, lang, po_file):
+        locale_dir = 'share/locale/%s/LC_MESSAGES' % lang
+        mkdir_p(locale_dir)
+        self._run_subprocess([
+            'msgfmt', '-o',
+            os.path.join(locale_dir, 'youtube_dl.mo'),
+            po_file])
+
+    def update_po_internal(self, lang, po_file):
+        old_po_file = po_file + '.old'
+        os.rename(po_file, old_po_file)
+        self._run_subprocess([
+            'msgmerge', '-N', old_po_file, '-o', po_file, self.get_pot_filename()])
+
+    def for_all_po(self, callback):
+        for f in os.listdir(self.get_po_root()):
+            name, ext = os.path.splitext(f)
+            if ext != '.po':
+                continue
+
+            callback(name, os.path.join(self.get_po_root(), f))
+
+    def update_gmo(self):
+        self.for_all_po(self.update_gmo_internal)
+
+    def update_po(self):
+        self.for_all_po(self.update_po_internal)
+
+    def update_pot(self):
+        self._run_subprocess
+        cmds = [
+            'xgettext', '-d', self.GETTEXT_DOMAIN, '-j', '-k', '-kg', '--from-code=utf-8', '-o',
+            self.get_pot_filename()]
+        cmds.extend(glob.glob('youtube_dl/*.py') + glob.glob('youtube_dl/*/*.py'))
+        self._run_subprocess(cmds)
+
+
+def main(argv):
+    instance = I18N_Utils()
+    if argv[1] == 'update-po':
+        instance.update_po()
+    elif argv[1] == 'update-gmo':
+        instance.update_gmo()
+    elif argv[1] == 'update-pot':
+        instance.update_pot()
+
+if __name__ == '__main__':
+    main(sys.argv)