1 files changed, 125 insertions, 0 deletions
diff --git a/src/semanticstore/layoutmanager.py b/src/semanticstore/layoutmanager.py
new file mode 100644
index 0000000..11623e8
--- /dev/null
+++ b/src/semanticstore/layoutmanager.py
@@ -0,0 +1,125 @@
+# Copyright (C) 2008, One Laptop Per Child
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+import os
+import logging
+import httplib
+import urllib
+
+MAX_QUERY_LIMIT = 40960
+CURRENT_LAYOUT_VERSION = 6
+
+
+class LayoutManager(object):
+    """Provide the logic about how entries are stored inside the datastore
+    directory
+    """
+
+    def __init__(self):
+        profile = os.environ.get('SUGAR_PROFILE', 'default')
+        base_dir = os.path.join(os.path.expanduser('~'), '.sugar', profile)
+
+        self._root_path = os.path.join(base_dir, 'datastore')
+
+        if not os.path.exists(self._root_path):
+            os.makedirs(self._root_path)
+
+        self._create_if_needed(self.get_checksums_dir())
+        self._create_if_needed(self.get_queue_path())
+
+    def _create_if_needed(self, path):
+        if not os.path.exists(path):
+            os.makedirs(path)
+
+    def get_version(self):
+        version_path = os.path.join(self._root_path, 'version')
+        version = 0
+        if os.path.exists(version_path):
+            try:
+                version = int(open(version_path, 'r').read())
+            except ValueError:
+                logging.exception('Can not read layout version')
+                version = 0
+
+        return version
+
+    def set_version(self, version):
+        version_path = os.path.join(self._root_path, 'version')
+        open(version_path, 'w').write(str(version))
+
+    def get_entry_path(self, uid):
+        # os.path.join() is just too slow
+        return '%s/%s/%s' % (self._root_path, uid[:2], uid)
+
+    def get_data_path(self, uid):
+        return '%s/%s/%s/data' % (self._root_path, uid[:2], uid)
+
+    def get_metadata_path(self, uid):
+        return '%s/%s/%s/metadata' % (self._root_path, uid[:2], uid)
+
+    def get_root_path(self):
+        return self._root_path
+
+    def get_index_path(self):
+        return os.path.join(self._root_path, 'index')
+
+    def get_checksums_dir(self):
+        return os.path.join(self._root_path, 'checksums')
+
+    def get_queue_path(self):
+        return os.path.join(self.get_checksums_dir(), 'queue')
+
+    def find_all(self):
+        logging.debug('[LMA] find all')
+        uids = []
+        query = """SELECT ?uid WHERE {
+            ?s <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.org/terms#DSObject>. 
+            ?s <http://example.org/terms#uid> ?uid. 
+            }"""
+        params = {'query': query, 'format' : 'csv'}
+        headers = {'Content-Type': 'application/x-www-form-urlencoded'}
+        conn = httplib.HTTPConnection('127.0.0.1:8080')
+        conn.request("POST", "/sparql", urllib.urlencode(params), headers=headers)
+        response = conn.getresponse()
+        results = response.read().split('\n')[1:-1]
+        logging.debug(results)
+        conn.close()
+        return uids
+
+    def is_empty(self):
+        """Check if there is any existing entry.
+
+        All data store layout versions are handled. Will err on the safe
+        side (i.e. return False if there might be any entry)."""
+        if os.path.exists(os.path.join(self._root_path, 'store')):
+            # unmigrated 0.82 data store
+            return False
+
+        for f in os.listdir(self._root_path):
+            if os.path.isdir(os.path.join(self._root_path, f)) and len(f) == 2:
+                for g in os.listdir(os.path.join(self._root_path, f)):
+                    if len(g) == 36:
+                        return False
+        return True
+
+_instance = None
+
+
+def get_instance():
+    global _instance
+    if _instance is None:
+        _instance = LayoutManager()
+    return _instance