Generate source maps from Closure Compiler

(imported from commit 0e4de860b1dba85aa43b60a2c819ac44403186c5)

zephyr/lib/minify.py

@@ -0,0 +1,19 @@
+from django.conf import settings
+from hashlib     import sha1
+from os          import path
+
+from pipeline.compressors import SubProcessCompressor
+
+class ClosureSourceMapCompressor(SubProcessCompressor):
+    def compress_js(self, js):
+        # js is the full text of the JavaScript source, and we can't
+        # easily get either the input file names or the output file
+        # name.  So we just pick a unique arbitrary name.  This is
+        # okay because we can figure out from the source map file
+        # contents which JavaScript files it corresponds to.
+        source_map = path.join(settings.PIPELINE_CLOSURE_SOURCE_MAP_DIR,
+                               sha1(js).hexdigest() + '.map')
+
+        command = '%s --create_source_map %s' % (
+            settings.PIPELINE_CLOSURE_BINARY, source_map)
+        return self.execute_command(command, js)