Merge pull request #281 from byexamples/Issue-280-Fix-Log-Lock-With-a-Non-None-Dummy-Lock

Issue 280 fix log lock with a non none dummy lock

Author: eldipa

.check-secrets.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+if [ -x .check-secrets-impl.sh ]; then
+    . .check-secrets-impl.sh
+elif [ -f .check-secrets-impl.sh ]; then
+    exit 1
+else
+    exit 0
+fi

.gitignore

@@ -17,3 +17,4 @@ prof-traces
 .workflow-log
 test/ds/good.args
 test/autocomplete_byexample.sh
+.check-secrets-impl.sh

.pre-commit-config.yaml

@@ -42,3 +42,13 @@ repos:
     rev: v2.29.0
     hooks:
     -   id: commitizen
+
+-   repo: local
+    hooks:
+    -   id: check-secrets
+        name: check secrets in files
+        language: script
+        entry: .check-secrets.sh
+        always_run: true
+        verbose: true
+        stages: ["push"]

byexample/log.py

@@ -334,6 +334,35 @@ def log_with(logger_name, child=True):
     finally:
         _logger_stack.pop()
 
+class _DummyRLock:
+    '''
+    A dummy reentrant lock to emulate a lock (acquire/release) but without
+    any overhead. Of course, without any mutual exclusion either!
+
+    We use _DummyRLock for XStreamHandler where we are OK with a thread-unsafe
+    implementation because XStreamHandler's emit() will handle the thread-safety
+    or it will delegate the call to someone than manages the thread-safety itself
+    (the concerns set).
+    '''
+    def __init__(self):
+        self._cnt = 0
+
+    def acquire(self, *args, **kargs):
+        self._cnt += 1
+
+    def release(self):
+        self._cnt -= 1
+        self._cnt = max(self._cnt, 0)
+
+    def locked(self):
+        return self._cnt > 0
+
+    def __enter__(self):
+        self.acquire()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.release()
 
 class XStreamHandler(logging.StreamHandler):
     def __init__(self, *args, **kargs):
@@ -366,13 +395,7 @@ def emit(self, record):
             self.handleError(record)
 
     def createLock(self):
-        self.lock = None
-
-    def acquire(self):
-        return
-
-    def release(self):
-        return
+        self.lock = _DummyRLock()
 
     def handleError(self, record):
         # handleError is called when an error happend during the logging.