Mechanism to lock compilation directory: first implementation using ugly PLearn's lock

theano/gof/compilelock.py

+# Locking mechanism.
+
+import compiledir
+import os
+from plearn.utilities.write_results import lockFile, unlockFile
+
+def get_lock():
+    """
+    Obtain lock on compilation directory.
+    """
+    if not hasattr(get_lock, 'n_lock'):
+        # Initialization.
+        get_lock.n_lock = 0
+        get_lock.lock_file = os.path.join(compiledir.get_compiledir(), 'lock')
+        if not hasattr(get_lock, 'lock_is_enabled'):
+            get_lock.lock_is_enabled = True
+    # Only really try to acquire the lock if we do not have it already.
+    if get_lock.lock_is_enabled and get_lock.n_lock == 0:
+        lockFile(get_lock.lock_file, timeout = 60, verbosity = 10)
+    get_lock.n_lock += 1
+
+def release_lock():
+    """
+    Release lock on compilation directory.
+    """
+    get_lock.n_lock -= 1
+    assert get_lock.n_lock >= 0
+    # Only really release lock once all lock requests have ended.
+    if get_lock.lock_is_enabled and get_lock.n_lock == 0:
+        unlockFile(get_lock.lock_file)
+
+def set_lock_status(use_lock):
+    """
+    Enable or disable the lock on the compilation directory (which is enabled
+    by default). Disabling may make compilation slightly faster (but is not
+    recommended for parallel execution).
+
+    @param use_lock: whether to use the compilation lock or not
+    @type  use_lock: bool
+    """
+    get_lock.lock_is_enabled = use_lock
+