Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/lldb/packages/Python/lldbsuite/test/lock.py

@@ -0,0 +1,28 @@
+"""
+Interprocess mutex based on file locks
+"""
+
+import fcntl
+import os
+
+
+class Lock:
+
+    def __init__(self, filename):
+        self.filename = filename
+        # This will create it if it does not exist already
+        unbuffered = 0
+        self.handle = open(filename, 'a+', unbuffered)
+
+    def acquire(self):
+        fcntl.flock(self.handle, fcntl.LOCK_EX)
+
+    # will throw IOError if unavailable
+    def try_acquire(self):
+        fcntl.flock(self.handle, fcntl.LOCK_NB | fcntl.LOCK_EX)
+
+    def release(self):
+        fcntl.flock(self.handle, fcntl.LOCK_UN)
+
+    def __del__(self):
+        self.handle.close()