diff options
Diffstat (limited to 'src/server/PreProcessor.cpp')
| -rw-r--r-- | src/server/PreProcessor.cpp | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/server/PreProcessor.cpp b/src/server/PreProcessor.cpp index aa4f0b06..f786ca10 100644 --- a/src/server/PreProcessor.cpp +++ b/src/server/PreProcessor.cpp @@ -56,6 +56,8 @@ PreProcessor::event(Event* const ev) assert(!ev->is_prepared()); assert(!ev->next()); + /* Note that tail is only used here, not in process(). The head must be + checked first here, since if it is NULL the tail pointer is junk. */ Event* const head = _head.load(); if (!head) { _head = ev; @@ -105,9 +107,9 @@ PreProcessor::process(ProcessContext& context, PostProcessor& dest, size_t limit // Since _head was not NULL, we know it hasn't been changed since _head = next; - /* If next is NULL, then _tail may now be invalid. However, in this - case _head is also NULL so event() will not read _tail. Since it - could cause a race with event(), _tail is not set to NULL here. */ + /* If next is NULL, then _tail may now be invalid. However, it would cause + a race to reset _tail here. Instead, append() checks only _head for + emptiness, and resets the tail appropriately. */ } return n_processed; |