diff options
| -rw-r--r-- | lib/spack/llnl/util/lock.py | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/spack/llnl/util/lock.py b/lib/spack/llnl/util/lock.py index 6e49bf74e6..dcca37687e 100644 --- a/lib/spack/llnl/util/lock.py +++ b/lib/spack/llnl/util/lock.py @@ -95,10 +95,15 @@ class Lock(object): order, but the POSIX lock is held until all local read and write locks are released. + Returns True if it is the first acquire and actually acquires + the POSIX lock, False if it is a nested transaction. + """ - if self._reads == 0 and self._writes == 0: - self._lock(fcntl.LOCK_SH, timeout) self._reads += 1 + if self._reads == 1 and self._writes == 0: + self._lock(fcntl.LOCK_SH, timeout) + return True + return False def acquire_write(self, timeout=_default_timeout): @@ -107,10 +112,16 @@ class Lock(object): Read and write locks can be acquired and released in arbitrary order, but the POSIX lock is held until all local read and write locks are released. + + Returns True if it is the first acquire and actually acquires + the POSIX lock, False if it is a nested transaction. + """ - if self._writes == 0: - self._lock(fcntl.LOCK_EX, timeout) self._writes += 1 + if self._writes == 1: + self._lock(fcntl.LOCK_EX, timeout) + return True + return False def release_read(self): |