1 files changed, 152 insertions, 0 deletions
diff --git a/webapp/django/core/cache/backends/filebased.py b/webapp/django/core/cache/backends/filebased.py
new file mode 100644
index 0000000000..181197a8d7
--- /dev/null
+++ b/webapp/django/core/cache/backends/filebased.py
@@ -0,0 +1,152 @@
+"File-based cache backend"
+
+import os
+import time
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+from django.core.cache.backends.base import BaseCache
+from django.utils.hashcompat import md5_constructor
+
+class CacheClass(BaseCache):
+    def __init__(self, dir, params):
+        BaseCache.__init__(self, params)
+
+        max_entries = params.get('max_entries', 300)
+        try:
+            self._max_entries = int(max_entries)
+        except (ValueError, TypeError):
+            self._max_entries = 300
+
+        cull_frequency = params.get('cull_frequency', 3)
+        try:
+            self._cull_frequency = int(cull_frequency)
+        except (ValueError, TypeError):
+            self._cull_frequency = 3
+
+        self._dir = dir
+        if not os.path.exists(self._dir):
+            self._createdir()
+
+    def add(self, key, value, timeout=None):
+        if self.has_key(key):
+            return False
+
+        self.set(key, value, timeout)
+        return True
+
+    def get(self, key, default=None):
+        fname = self._key_to_file(key)
+        try:
+            f = open(fname, 'rb')
+            exp = pickle.load(f)
+            now = time.time()
+            if exp < now:
+                f.close()
+                self._delete(fname)
+            else:
+                return pickle.load(f)
+        except (IOError, OSError, EOFError, pickle.PickleError):
+            pass
+        return default
+
+    def set(self, key, value, timeout=None):
+        fname = self._key_to_file(key)
+        dirname = os.path.dirname(fname)
+
+        if timeout is None:
+            timeout = self.default_timeout
+
+        self._cull()
+
+        try:
+            if not os.path.exists(dirname):
+                os.makedirs(dirname)
+
+            f = open(fname, 'wb')
+            now = time.time()
+            pickle.dump(now + timeout, f, pickle.HIGHEST_PROTOCOL)
+            pickle.dump(value, f, pickle.HIGHEST_PROTOCOL)
+        except (IOError, OSError):
+            pass
+
+    def delete(self, key):
+        try:
+            self._delete(self._key_to_file(key))
+        except (IOError, OSError):
+            pass
+
+    def _delete(self, fname):
+        os.remove(fname)
+        try:
+            # Remove the 2 subdirs if they're empty
+            dirname = os.path.dirname(fname)
+            os.rmdir(dirname)
+            os.rmdir(os.path.dirname(dirname))
+        except (IOError, OSError):
+            pass
+
+    def has_key(self, key):
+        fname = self._key_to_file(key)
+        try:
+            f = open(fname, 'rb')
+            exp = pickle.load(f)
+            now = time.time()
+            if exp < now:
+                f.close()
+                self._delete(fname)
+                return False
+            else:
+                return True
+        except (IOError, OSError, EOFError, pickle.PickleError):
+            return False
+
+    def _cull(self):
+        if int(self._num_entries) < self._max_entries:
+            return
+
+        try:
+            filelist = os.listdir(self._dir)
+        except (IOError, OSError):
+            return
+
+        if self._cull_frequency == 0:
+            doomed = filelist
+        else:
+            doomed = [os.path.join(self._dir, k) for (i, k) in enumerate(filelist) if i % self._cull_frequency == 0]
+
+        for topdir in doomed:
+            try:
+                for root, _, files in os.walk(topdir):
+                    for f in files:
+                        self._delete(os.path.join(root, f))
+            except (IOError, OSError):
+                pass
+
+    def _createdir(self):
+        try:
+            os.makedirs(self._dir)
+        except OSError:
+            raise EnvironmentError, "Cache directory '%s' does not exist and could not be created'" % self._dir
+
+    def _key_to_file(self, key):
+        """
+        Convert the filename into an md5 string. We'll turn the first couple
+        bits of the path into directory prefixes to be nice to filesystems
+        that have problems with large numbers of files in a directory.
+
+        Thus, a cache key of "foo" gets turnned into a file named
+        ``{cache-dir}ac/bd/18db4cc2f85cedef654fccc4a4d8``.
+        """
+        path = md5_constructor(key.encode('utf-8')).hexdigest()
+        path = os.path.join(path[:2], path[2:4], path[4:])
+        return os.path.join(self._dir, path)
+
+    def _get_num_entries(self):
+        count = 0
+        for _,_,files in os.walk(self._dir):
+            count += len(files)
+        return count
+    _num_entries = property(_get_num_entries)