Disable-do-trace-method-evaluation-when-PYUSB-DEBUG-LEVEL-is-not-defined.patch

From fac469a6320b7d6649f52b76ff4955c8e787d834 Mon Sep 17 00:00:00 2001
From: Emmanuel Blot <eblot@neotion.com>
Date: Tue, 5 Apr 2011 12:10:18 +0200
Subject: [PATCH] Disable do_trace method evaluation when PYUSB_DEBUG_LEVEL is not defined

---
 usb/__init__.py |    2 ++
 usb/_debug.py   |   10 ++++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/usb/__init__.py b/usb/__init__.py
index 7d820d0..27f7c71 100644
--- a/usb/__init__.py
+++ b/usb/__init__.py
@@ -47,10 +47,12 @@ __all__ = ['legacy', 'core', 'backend', 'util']
 
 
 def _setup_log():
+    from usb import _debug
     logger = logging.getLogger('usb')
     debug_level = os.getenv('PYUSB_DEBUG_LEVEL')
 
     if debug_level is not None:
+        _debug.enable_tracing(True)
         filename = os.getenv('PYUSB_LOG_FILENAME')
 
         LEVELS = {'debug': logging.DEBUG,
diff --git a/usb/_debug.py b/usb/_debug.py
index 0b3f765..13b0ced 100644
--- a/usb/_debug.py
+++ b/usb/_debug.py
@@ -33,6 +33,12 @@ __all__ = ['methodtrace', 'functiontrace']
 import logging
 import usb._interop as _interop
 
+_enable_tracing = False
+
+def enable_tracing(enable):
+    global _enable_tracing
+    _enable_tracing = enable
+
 def _trace_function_call(logger, fname, *args, **named_args):
     logger.debug(
                 # TODO: check if 'f' is a method or a free function
@@ -44,6 +50,8 @@ def _trace_function_call(logger, fname, *args, **named_args):
 # decorator for methods calls tracing
 def methodtrace(logger):
     def decorator_logging(f):
+        if not _enable_tracing:
+            return f
         def do_trace(*args, **named_args):
             # this if is just a optimization to avoid unecessary string formatting
             if logging.DEBUG >= logger.getEffectiveLevel():
@@ -57,6 +65,8 @@ def methodtrace(logger):
 # decorator for methods calls tracing
 def functiontrace(logger):
     def decorator_logging(f):
+        if not _enable_tracing:
+            return f
         def do_trace(*args, **named_args):
             # this if is just a optimization to avoid unecessary string formatting
             if logging.DEBUG >= logger.getEffectiveLevel():
-- 
1.7.4.1+GitX