jpegtran plugin (like jpegoptim plugin)

This plugin may seem redundant with jpegoptim one. jpegtran allows one
to produce progressive JPEG while jpegoptim does not. On the other
hand, jpegtran only does losless compression while jpegoptim allows
one to set a maximum quality setting.

hyde/ext/plugins/jpegtran.py

@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+"""
+jpegtran plugin
+
+Almost like jpegoptim except it uses jpegtran. jpegtran allows to make
+progressive JPEG. Unfortunately, it only does lossless compression. If
+you want both, you need to combine this plugin with jpegoptim one.
+"""
+
+from hyde.plugin import CLTransformer
+from hyde.fs import File
+
+class JPEGTranPlugin(CLTransformer):
+    """
+    The plugin class for JPEGTran
+    """
+
+    def __init__(self, site):
+        super(JPEGTranPlugin, self).__init__(site)
+
+    @property
+    def plugin_name(self):
+        """
+        The name of the plugin.
+        """
+        return "jpegtran"
+
+    def option_prefix(self, option):
+        return "-"
+
+    def binary_resource_complete(self, resource):
+        """
+        If the site is in development mode, just return.
+        Otherwise, run jpegtran to compress the jpg file.
+        """
+
+        try:
+            mode = self.site.config.mode
+        except AttributeError:
+            mode = "production"
+
+        if not resource.source_file.kind == 'jpg':
+            return
+
+        if mode.startswith('dev'):
+            self.logger.debug("Skipping jpegtran in development mode.")
+            return
+
+        supported = [
+            "optimize",
+            "progressive",
+            "restart",
+            "arithmetic",
+            "perfect",
+            "copy",
+        ]
+        source = File(self.site.config.deploy_root_path.child(
+                resource.relative_deploy_path))
+        target = File.make_temp('')
+        jpegtran = self.app
+        args = [unicode(jpegtran)]
+        args.extend(self.process_args(supported))
+        args.extend(["-outfile", unicode(target), unicode(source)])
+        self.call_app(args)
+        target.copy_to(source)
+        target.delete()