Rev 4845: (mbp) remove extra buffer flushing on trace file in file:///home/pqm/archives/thelove/bzr/%2Btrunk/

[Canonical.com Patch Queue Manager]

At file:///home/pqm/archives/thelove/bzr/%2Btrunk/

------------------------------------------------------------
revno: 4845 [merge]
revision-id: pqm at pqm.ubuntu.com-20091201053552-yws5hsfrricui8b6
parent: pqm at pqm.ubuntu.com-20091201024020-8uqp6v8p2xqppu36
parent: mbp at sourcefrog.net-20091130060926-3e26u3qtibr1nolj
committer: Canonical.com Patch Queue Manager <pqm at pqm.ubuntu.com>
branch nick: +trunk
timestamp: Tue 2009-12-01 05:35:52 +0000
message:
  (mbp) remove extra buffer flushing on trace file
modified:
  NEWS                           NEWS-20050323055033-4e00b5db738777ff
  bzrlib/trace.py                trace.py-20050309040759-c8ed824bdcd4748a
=== modified file 'NEWS'
--- a/NEWS	2009-11-30 12:24:55 +0000
+++ b/NEWS	2009-12-01 05:35:52 +0000
@@ -182,6 +182,9 @@
 * Shelve command refuse to run if there is no real terminal.
   (Alexander Belchenko)
 
+* Avoid unnecessarily flushing of trace file; it's now unbuffered at the
+  Python level.  (Martin Pool)
+
 Documentation
 *************
 

=== modified file 'bzrlib/trace.py'
--- a/bzrlib/trace.py	2009-11-19 20:47:51 +0000
+++ b/bzrlib/trace.py	2009-12-01 05:35:52 +0000
@@ -1,4 +1,4 @@
-# Copyright (C) 2005, 2006, 2007, 2008 Canonical Ltd
+# Copyright (C) 2005, 2006, 2007, 2008, 2009 Canonical Ltd
 #
 # 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
@@ -153,13 +153,11 @@
     _bzr_logger.error(*args, **kwargs)
 
 
-_last_mutter_flush_time = None
-
-
 def mutter(fmt, *args):
-    global _last_mutter_flush_time
     if _trace_file is None:
         return
+    # XXX: Don't check this every time; instead anyone who closes the file
+    # ought to deregister it.  We can tolerate None.
     if (getattr(_trace_file, 'closed', None) is not None) and _trace_file.closed:
         return
 
@@ -182,15 +180,7 @@
     timestamp = '%0.3f  ' % (now - _bzr_log_start_time,)
     out = timestamp + out + '\n'
     _trace_file.write(out)
-    # We flush if we haven't flushed for a few seconds. We don't want to flush
-    # on every mutter, but when a command takes a while, it can be nice to see
-    # updates in the debug log.
-    if (_last_mutter_flush_time is None
-        or (now - _last_mutter_flush_time) > 2.0):
-        flush = getattr(_trace_file, 'flush', None)
-        if flush is not None:
-            flush()
-        _last_mutter_flush_time = now
+    # there's no explicit flushing; the file is typically line buffered.
 
 
 def mutter_callsite(stacklevel, fmt, *args):
@@ -251,7 +241,7 @@
     _bzr_log_filename = _get_bzr_log_filename()
     _rollover_trace_maybe(_bzr_log_filename)
     try:
-        bzr_log_file = open(_bzr_log_filename, 'at', 1) # line buffered
+        bzr_log_file = open(_bzr_log_filename, 'at', buffering=0) # unbuffered
         # bzr_log_file.tell() on windows always return 0 until some writing done
         bzr_log_file.write('\n')
         if bzr_log_file.tell() <= 2: