Cache _open() result in zc/buildout/buildout.py to accelerate extends.

CHANGES.SlapOS.txt

+1.7.1-dev-SlapOS-004
+--------------------
+
+- Cache _open() result in zc/buildout/buildout.py to accelerate extends.
+
 1.7.1-dev-SlapOS-003
 --------------------
 

setup.py

@@ -12,7 +12,7 @@
 #
 ##############################################################################
 name = "zc.buildout"
-version = "1.7.1-dev-SlapOS-003"
+version = "1.7.1-dev-SlapOS-004"
 
 import os
 from setuptools import setup

src/zc/buildout/buildout.py

@@ -1691,6 +1691,7 @@ def _save_options(section, options, f):
     for option in sorted(options.keys()):
         _save_option(option, options.get(option), f)
 
+_open_result_cache = {}
 def _open(base, filename, seen, dl_options, override, downloaded):
     """Open a configuration file and return the result as a dictionary,
 
@@ -1730,6 +1731,9 @@ def _open(base, filename, seen, dl_options, override, downloaded):
         base = os.path.dirname(filename)
     downloaded.add(filename)
 
+    if filename in _open_result_cache:
+        return _open_result_cache[filename]
+
     if filename in seen:
         if is_temp:
             fp.close()
@@ -1790,6 +1794,7 @@ def _open(base, filename, seen, dl_options, override, downloaded):
         result = _update(eresult, result)
 
     seen.pop()
+    _open_result_cache[filename] = result
     return result