Rev 2329: Tune the pack_stat step to not go through as many layers of indirection when possible. in file:///home/robertc/source/baz/dirstate2/

[Robert Collins]

At file:///home/robertc/source/baz/dirstate2/

------------------------------------------------------------
revno: 2329
revision-id: robertc at robertcollins.net-20070309213148-mmgmddc0a2yheitu
parent: robertc at robertcollins.net-20070309155213-fciselcj7bjb6swy
committer: Robert Collins <robertc at robertcollins.net>
branch nick: dirstate2
timestamp: Sat 2007-03-10 08:31:48 +1100
message:
  Tune the pack_stat step to not go through as many layers of indirection when possible.
modified:
  bzrlib/path_info_python.py     path_info_python.py-20070309041626-f8val8ukxzzzyudi-2
=== modified file 'bzrlib/path_info_python.py'
--- a/bzrlib/path_info_python.py	2007-03-09 14:30:19 +0000
+++ b/bzrlib/path_info_python.py	2007-03-09 21:31:48 +0000
@@ -21,7 +21,7 @@
 
 __all__ = ['pack_stat', 'path_info']
 
-import base64
+import binascii
 import errno
 import os
 import stat
@@ -35,19 +35,24 @@
 kind_file = sys.modules['bzrlib.path_info'].kind_file
 
 
-def pack_stat(st, _encode=base64.encodestring, _pack=struct.pack):
-    """Convert stat values into a packed representation."""
-    # jam 20060614 it isn't really worth removing more entries if we
-    # are going to leave it in packed form.
-    # With only st_mtime and st_mode filesize is 5.5M and read time is 275ms
-    # With all entries filesize is 5.9M and read time is mabye 280ms
-    # well within the noise margin
-
-    # base64.encode always adds a final newline, so strip it off
-    return _encode(_pack('>llllll'
-        , st.st_size, int(st.st_mtime), int(st.st_ctime)
-        , st.st_dev, st.st_ino, st.st_mode))[:-1]
-
+if not getattr(struct, '_compile', None):
+    def pack_stat(st, _b2a_base64=binascii.b2a_base64, _pack=struct.pack):
+        """Convert stat values into a packed representation."""
+        # base64.encode always adds a final newline, so strip it off
+        return _b2a_base64(_pack('>llllll'
+            , st.st_size, int(st.st_mtime), int(st.st_ctime)
+            , st.st_dev, st.st_ino, st.st_mode))[:-1]
+else:
+    # compile the struct compiler we need, because bytecode sucks.
+    from _struct import Struct
+    stat_packer = Struct('>llllll').pack
+    def pack_stat(st, _b2a_base64=binascii.b2a_base64, _pack=stat_packer):
+        """Convert stat values into a packed representation."""
+        # base64.encode always adds a final newline, so strip it off
+        return _b2a_base64(_pack(
+            st.st_size, int(st.st_mtime), int(st.st_ctime),
+            st.st_dev, st.st_ino, st.st_mode))[:-1]
+         
 
 def path_info(abspath, _lstat=os.lstat, _mapper=file_kind_from_stat_mode,
     _S_IEXEC=stat.S_IEXEC, _ENOENT=errno.ENOENT, _kind_missing=kind_missing,