diff options
| -rw-r--r-- | src/server/PreProcessor.cpp | 46 |
1 files changed, 21 insertions, 25 deletions
diff --git a/src/server/PreProcessor.cpp b/src/server/PreProcessor.cpp index 08d7bb4d..34ae48e7 100644 --- a/src/server/PreProcessor.cpp +++ b/src/server/PreProcessor.cpp @@ -33,8 +33,7 @@ PreProcessor::PreProcessor() } PreProcessor::~PreProcessor() -{ -} +{} void PreProcessor::event(Event* const ev) @@ -47,14 +46,12 @@ PreProcessor::event(Event* const ev) assert(!ev->next()); Event* const head = _head.get(); - Event* const tail = _tail.get(); - if (!head) { _head = ev; _tail = ev; } else { + _tail.get()->next(ev); _tail = ev; - tail->next(ev); } if (!_prepared_back.get()) { @@ -72,18 +69,14 @@ PreProcessor::process(ProcessContext& context, PostProcessor& dest, bool limit) return 0; } - /* Limit the maximum number of queued events to process per cycle. This - makes the process callback (more) realtime-safe by preventing being - choked by events coming in faster than they can be processed. - FIXME: test this and figure out a good value - */ - const size_t MAX_QUEUED_EVENTS = context.nframes() / 32; - - size_t num_events_processed = 0; - - Event* ev = head; - Event* last = ev; + /* Limit the maximum number of events to process each cycle to ensure the + process callback is real-time safe. TODO: Parameterize this and/or + figure out a good default value. */ + const size_t MAX_EVENTS_PER_CYCLE = context.nframes() / 4; + size_t n_processed = 0; + Event* ev = head; + Event* last = ev; while (ev && ev->is_prepared() && ev->time() < context.end()) { if (ev->time() < context.start()) { // Didn't get around to executing in time, oh well... @@ -91,26 +84,29 @@ PreProcessor::process(ProcessContext& context, PostProcessor& dest, bool limit) } ev->execute(context); last = ev; - ev = (Event*)ev->next(); - ++num_events_processed; - if (limit && (num_events_processed > MAX_QUEUED_EVENTS)) + ev = ev->next(); + ++n_processed; + if (limit && (n_processed > MAX_EVENTS_PER_CYCLE)) { break; + } } - if (num_events_processed > 0) { + if (n_processed > 0) { Event* next = (Event*)last->next(); last->next(NULL); dest.append(context, head, last); + + // Since _head was not NULL, we know it hasn't been changed since _head = next; - if (!next) { - _tail = NULL; - } + + /* 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. */ } - return num_events_processed; + return n_processed; } -/** Pre-process a single event */ void PreProcessor::_run() { |