Cache code cleanup

dedupestore/cache.py

@@ -1,3 +1,4 @@
+from itertools import ifilter
 import logging
 import msgpack
 import os
@@ -14,7 +15,6 @@ class Cache(object):
         self.path = os.path.join(os.path.expanduser('~'), '.dedupestore', 'cache',
                                  '%s.cache' % self.store.uuid)
         self.tid = -1
-        self.file_chunks = {}
         self.open()
         if self.tid != self.store.tid:
             self.init(crypto)
@@ -24,21 +24,17 @@ class Cache(object):
             return
         cache = msgpack.unpackb(open(self.path, 'rb').read())
         assert cache['version'] == 1
-        if cache['store'] != self.store.uuid:
-            raise Exception('Cache UUID mismatch')
-        self.chunkmap = cache['chunkmap']
+        self.chunk_counts = cache['chunk_counts']
         # Discard old file_chunks entries
-        for hash, entry in cache['file_chunks'].iteritems():
-            count = entry[0]
-            if count < 8:
-                self.file_chunks[hash] = [count + 1] + list(entry[1:])
+        self.file_chunks = cache['file_chunks']
         self.tid = cache['tid']
 
     def init(self, crypto):
         """Initializes cache by fetching and reading all archive indicies
         """
         logging.info('Initializing cache...')
-        self.chunkmap = {}
+        self.chunk_counts = {}
+        self.file_chunks = {}
         self.tid = self.store.tid
         if self.store.tid == 0:
             return
@@ -47,19 +43,19 @@ class Cache(object):
             cindex = msgpack.unpackb(data)
             for id, size in cindex['chunks']:
                 try:
-                    count, size = self.chunkmap[id]
-                    self.chunkmap[id] = count + 1, size
+                    count, size = self.chunk_counts[id]
+                    self.chunk_counts[id] = count + 1, size
                 except KeyError:
-                    self.chunkmap[id] = 1, size
+                    self.chunk_counts[id] = 1, size
         self.save()
 
     def save(self):
         assert self.store.state == self.store.OPEN
         cache = {'version': 1,
-                'store': self.store.uuid,
-                'chunkmap': self.chunkmap,
                 'tid': self.store.tid,
-                'file_chunks': self.file_chunks,
+                'chunk_counts': self.chunk_counts,
+                'file_chunks': dict(ifilter(lambda i: i[1][0] < 8,
+                                            self.file_chunks.iteritems())),
         }
         data = msgpack.packb(cache)
         cachedir = os.path.dirname(self.path)
@@ -74,31 +70,31 @@ class Cache(object):
         data, hash = crypto.encrypt_read(data)
         csize = len(data)
         self.store.put(NS_CHUNK, id, data)
-        self.chunkmap[id] = (1, csize)
+        self.chunk_counts[id] = (1, csize)
         return csize
 
     def seen_chunk(self, id):
-        count, size = self.chunkmap.get(id, (0, 0))
-        return count
+        return self.chunk_counts.get(id, (0, 0))[0]
 
     def chunk_incref(self, id):
-        count, size = self.chunkmap[id]
-        self.chunkmap[id] = (count + 1, size)
+        count, size = self.chunk_counts[id]
+        self.chunk_counts[id] = (count + 1, size)
         return size
 
     def chunk_decref(self, id):
-        count, size = self.chunkmap[id]
+        count, size = self.chunk_counts[id]
         if count == 1:
-            del self.chunkmap[id]
+            del self.chunk_counts[id]
             self.store.delete(NS_CHUNK, id)
         else:
-            self.chunkmap[id] = (count - 1, size)
+            self.chunk_counts[id] = (count - 1, size)
 
     def file_known_and_unchanged(self, path_hash, st):
         entry = self.file_chunks.get(path_hash)
-        if (entry and entry[1] == st.st_ino
-            and entry[2] == st.st_size and entry[3] == st.st_mtime):
-            entry[0] = 0 # reset entry age
+        if (entry and entry[3] == st.st_mtime
+            and entry[2] == st.st_size and entry[1] == st.st_ino):
+            # reset entry age
+            self.file_chunks[path_hash] = (0,) + entry[1:]
             return entry[4], entry[2]
         else:
             return None, 0