diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/handler_stack.coffee | 60 |
1 files changed, 37 insertions, 23 deletions
diff --git a/lib/handler_stack.coffee b/lib/handler_stack.coffee index 2a44d26b..c17be24f 100644 --- a/lib/handler_stack.coffee +++ b/lib/handler_stack.coffee @@ -9,16 +9,22 @@ class HandlerStack # A handler should return this value to immediately discontinue bubbling and pass the event on to the # underlying page. - @stopBubblingAndTrue = new Object() + @passEventToPage = new Object() # A handler should return this value to indicate that the event has been consumed, and no further # processing should take place. The event does not propagate to the underlying page. - @stopBubblingAndFalse = new Object() + @suppressPropagation = new Object() # A handler should return this value to indicate that bubbling should be restarted. Typically, this is # used when, while bubbling an event, a new mode is pushed onto the stack. @restartBubbling = new Object() + # A handler should return this value to continue bubbling the event. + @continueBubbling = true + + # A handler should return this value to suppress an event. + @suppressEvent = false + # Adds a handler to the top of the stack. Returns a unique ID for that handler that can be used to remove it # later. push: (handler) -> @@ -34,27 +40,35 @@ class HandlerStack handler.id = ++@counter # Called whenever we receive a key or other event. Each individual handler has the option to stop the - # event's propagation by returning a falsy value, or stop bubbling by returning @stopBubblingAndFalse or - # @stopBubblingAndTrue. + # event's propagation by returning a falsy value, or stop bubbling by returning @suppressPropagation or + # @passEventToPage. bubbleEvent: (type, event) -> @eventNumber += 1 eventNumber = @eventNumber - # We take a copy of the array in order to avoid interference from concurrent removes (for example, to - # avoid calling the same handler twice, because elements have been spliced out of the array by remove). for handler in @stack[..].reverse() - # A handler may have been removed (handler.id == null), so check. - if handler?.id and handler[type] + # A handler might have been removed (handler.id == null), so check; or there might just be no handler + # for this type of event. + unless handler?.id and handler[type] + @logResult eventNumber, type, event, handler, "skip [#{handler[type]?}]" if @debug + else @currentId = handler.id result = handler[type].call this, event @logResult eventNumber, type, event, handler, result if @debug - if not result + if result == @passEventToPage + return true + else if result == @suppressPropagation + DomUtils.suppressPropagation event + return false + else if result == @restartBubbling + return @bubbleEvent type, event + else if result == @continueBubbling or (result and result != @suppressEvent) + true # Do nothing, but continue bubbling. + else + # result is @suppressEvent or falsy. DomUtils.suppressEvent event if @isChromeEvent event return false - return true if result == @stopBubblingAndTrue - return false if result == @stopBubblingAndFalse - return @bubbleEvent type, event if result == @restartBubbling - else - @logResult eventNumber, type, event, handler, "skip" if @debug + + # None of our handlers care about this event, so pass it to the page. true remove: (id = @currentId) -> @@ -74,21 +88,21 @@ class HandlerStack # Convenience wrappers. Handlers must return an approriate value. These are wrappers which handlers can # use to always return the same value. This then means that the handler itself can be implemented without # regard to its return value. - alwaysContinueBubbling: (handler) -> - handler() - true + alwaysContinueBubbling: (handler = null) -> + handler?() + @continueBubbling - neverContinueBubbling: (handler) -> - handler() - false + alwaysSuppressPropagation: (handler = null) -> + handler?() + @suppressPropagation # Debugging. logResult: (eventNumber, type, event, handler, result) -> label = switch result - when @stopBubblingAndTrue then "stop/true" - when @stopBubblingAndFalse then "stop/false" - when @restartBubbling then "rebubble" + when @passEventToPage then "passEventToPage" + when @suppressPropagation then "suppressPropagation" + when @restartBubbling then "restartBubbling" when "skip" then "skip" when true then "continue" label ||= if result then "continue/truthy" else "suppress" |