Rev 3826: Serialize the common lookup prefix, so that we don't have to compute it during deserialization. in http://bzr.arbash-meinel.com/branches/bzr/brisbane/hack

[John Arbash Meinel]

At http://bzr.arbash-meinel.com/branches/bzr/brisbane/hack

------------------------------------------------------------
revno: 3826
revision-id: john at arbash-meinel.com-20081224192457-80lac61kjh2lin23
parent: john at arbash-meinel.com-20081224180554-7qe1csn2l400xz2h
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: hack
timestamp: Wed 2008-12-24 13:24:57 -0600
message:
  Serialize the common lookup prefix, so that we don't have to compute it during deserialization.
-------------- next part --------------
=== modified file 'bzrlib/chk_map.py'
--- a/bzrlib/chk_map.py	2008-12-24 17:20:36 +0000
+++ b/bzrlib/chk_map.py	2008-12-24 19:24:57 +0000
@@ -511,10 +511,15 @@
             prefix_len = len(self._common_serialised_prefix)
             # prefix_len = 0
             bytes_for_items = (self._raw_size - (prefix_len * self._len))
+        if self._lookup_prefix is None:
+            lookup_len = 0
+        else:
+            lookup_len = len(self._lookup_prefix)
         return (9 # 'chkleaf:\n'
             + len(str(self._maximum_size)) + 1
             + len(str(self._key_width)) + 1
             + len(str(self._len)) + 1
+            + lookup_len + 1
             + prefix_len + 1
             + bytes_for_items)
 
@@ -534,10 +539,13 @@
         maximum_size = int(lines[1])
         width = int(lines[2])
         length = int(lines[3])
-        pos = 5
-        prefix = lines[4]
+        lookup_prefix = lines[4]
+        assert lookup_prefix[-1] == '\n'
+        lookup_prefix = lookup_prefix[:-1] # Remove the trailing newline
+        prefix = lines[5]
         assert prefix[-1] == '\n'
         prefix = prefix[:-1] # Remove the trailing newline
+        pos = 6
         while pos < len(lines):
             elements = (prefix + lines[pos]).split('\x00')
             assert len(elements) == width + 1
@@ -560,10 +568,18 @@
         result._key = key
         result._orig_key = key
         result._key_width = width
-        result._raw_size = (sum(map(len, lines[5:])) # the length of the suffix
+        result._raw_size = (sum(map(len, lines[6:])) # the length of the suffix
             + (length)*(len(prefix))) # prefix
-        result._compute_lookup_prefix()
-        result._compute_serialised_prefix()
+        if result._len == 0:
+            result._common_serialised_prefix = None
+            result._lookup_prefix = None
+        else:
+            result._common_serialised_prefix = prefix
+            result._lookup_prefix = lookup_prefix
+        # result._compute_lookup_prefix()
+        # assert result._lookup_prefix == lookup_prefix
+        # result._compute_serialised_prefix()
+        # assert result._common_serialised_prefix == prefix
         if len(bytes) != result._current_size():
             import pdb; pdb.set_trace()
         assert len(bytes) == result._current_size()
@@ -684,6 +700,10 @@
         lines.append("%d\n" % self._maximum_size)
         lines.append("%d\n" % self._key_width)
         lines.append("%d\n" % self._len)
+        if self._lookup_prefix is None:
+            lines.append('\n')
+        else:
+            lines.append('%s\n' % (self._lookup_prefix,))
         if self._common_serialised_prefix is None:
             lines.append('\n')
         else:
@@ -691,6 +711,7 @@
             # prefix_len = 0
             lines.append('%s\n' % (self._common_serialised_prefix,))
             prefix_len = len(self._common_serialised_prefix)
+
         for key, value in sorted(self._items.items()):
             value_lines = osutils.chunks_to_lines([value + '\n'])
             serialized = "%s\x00%s\n" % (self._serialise_key(key),
@@ -864,6 +885,7 @@
         result._raw_size = None # len(bytes)
         result._node_width = len(prefix)
         result._compute_lookup_prefix()
+        assert result._lookup_prefix == common_prefix
         return result
 
     def iteritems(self, store, key_filter=None):