--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/piecrust/processing/util.py	Sun Jan 18 12:13:28 2015 -0800
@@ -0,0 +1,83 @@
+import os.path
+import time
+import logging
+import yaml
+from piecrust.processing.base import Processor
+
+
+logger = logging.getLogger(__name__)
+
+
+class _ConcatInfo(object):
+    timestamp = 0
+    files = None
+    delim = "\n"
+
+
+class ConcatProcessor(Processor):
+    PROCESSOR_NAME = 'concat'
+
+    def __init__(self):
+        super(ConcatProcessor, self).__init__()
+        self._cache = {}
+
+    def matches(self, path):
+        return path.endswith('.concat')
+
+    def getDependencies(self, path):
+        info = self._load(path)
+        return info.files
+
+    def getOutputFilenames(self, filename):
+        return [filename[:-7]]
+
+    def process(self, path, out_dir):
+        dirname, filename = os.path.split(path)
+        out_path = os.path.join(out_dir, filename[:-7])
+        info = self._load(path)
+        if not info.files:
+            raise Exception("No files specified in: %s" %
+                            os.path.relpath(path, self.app.root_dir))
+
+        logger.debug("Concatenating %d files to: %s" %
+                     (len(info.files), out_path))
+        encoded_delim = info.delim.encode('utf8')
+        with open(out_path, 'wb') as ofp:
+            for p in info.files:
+                with open(p, 'rb') as ifp:
+                    ofp.write(ifp.read())
+                if info.delim:
+                    ofp.write(encoded_delim)
+        return True
+
+    def _load(self, path):
+        cur_time = time.time()
+        info = self._cache.get(path)
+        if (info is not None and
+                (cur_time - info.timestamp <= 1 or
+                 os.path.getmtime(path) < info.timestamp)):
+            return info
+
+        if info is None:
+            info = _ConcatInfo()
+            self._cache[path] = info
+
+        with open(path, 'r') as fp:
+            config = yaml.load(fp)
+
+        info.files = config.get('files', [])
+        info.delim = config.get('delim', "\n")
+        info.timestamp = cur_time
+
+        path_mode = config.get('path_mode', 'relative')
+        if path_mode == 'relative':
+            dirname, _ = os.path.split(path)
+            info.files = [os.path.join(dirname, f) for f in info.files]
+        elif path_mode == 'absolute':
+            info.files = [os.path.join(self.app.root_dir, f)
+                          for f in info.files]
+        else:
+            raise Exception("Unknown path mode: %s" % path_mode)
+
+        return info
+