animateQueue.js

'use strict';

var NG_ANIMATE_ATTR_NAME = 'data-ng-animate';
var NG_ANIMATE_PIN_DATA = '$ngAnimatePin';
var $$AnimateQueueProvider = ['$animateProvider', function($animateProvider) {
  var PRE_DIGEST_STATE = 1;
  var RUNNING_STATE = 2;

  var rules = this.rules = {
    skip: [],
    cancel: [],
    join: []
  };

  function isAllowed(ruleType, element, currentAnimation, previousAnimation) {
    return rules[ruleType].some(function(fn) {
      return fn(element, currentAnimation, previousAnimation);
    });
  }

  function hasAnimationClasses(options, and) {
    options = options || {};
    var a = (options.addClass || '').length > 0;
    var b = (options.removeClass || '').length > 0;
    return and ? a && b : a || b;
  }

  rules.join.push(function(element, newAnimation, currentAnimation) {
    // if the new animation is class-based then we can just tack that on
    return !newAnimation.structural && hasAnimationClasses(newAnimation.options);
  });

  rules.skip.push(function(element, newAnimation, currentAnimation) {
    // there is no need to animate anything if no classes are being added and
    // there is no structural animation that will be triggered
    return !newAnimation.structural && !hasAnimationClasses(newAnimation.options);
  });

  rules.skip.push(function(element, newAnimation, currentAnimation) {
    // why should we trigger a new structural animation if the element will
    // be removed from the DOM anyway?
    return currentAnimation.event == 'leave' && newAnimation.structural;
  });

  rules.skip.push(function(element, newAnimation, currentAnimation) {
    // if there is an ongoing current animation then don't even bother running the class-based animation
    return currentAnimation.structural && currentAnimation.state === RUNNING_STATE && !newAnimation.structural;
  });

  rules.cancel.push(function(element, newAnimation, currentAnimation) {
    // there can never be two structural animations running at the same time
    return currentAnimation.structural && newAnimation.structural;
  });

  rules.cancel.push(function(element, newAnimation, currentAnimation) {
    // if the previous animation is already running, but the new animation will
    // be triggered, but the new animation is structural
    return currentAnimation.state === RUNNING_STATE && newAnimation.structural;
  });

  rules.cancel.push(function(element, newAnimation, currentAnimation) {
    var nO = newAnimation.options;
    var cO = currentAnimation.options;

    // if the exact same CSS class is added/removed then it's safe to cancel it
    return (nO.addClass && nO.addClass === cO.removeClass) || (nO.removeClass && nO.removeClass === cO.addClass);
  });

  this.$get = ['$$rAF', '$rootScope', '$rootElement', '$document', '$$HashMap',
               '$$animation', '$$AnimateRunner', '$templateRequest', '$$jqLite', '$$forceReflow',
       function($$rAF,   $rootScope,   $rootElement,   $document,   $$HashMap,
                $$animation,   $$AnimateRunner,   $templateRequest,   $$jqLite,   $$forceReflow) {

    var activeAnimationsLookup = new $$HashMap();
    var disabledElementsLookup = new $$HashMap();
    var animationsEnabled = null;

    function postDigestTaskFactory() {
      var postDigestCalled = false;
      return function(fn) {
        // we only issue a call to postDigest before
        // it has first passed. This prevents any callbacks
        // from not firing once the animation has completed
        // since it will be out of the digest cycle.
        if (postDigestCalled) {
          fn();
        } else {
          $rootScope.$$postDigest(function() {
            postDigestCalled = true;
            fn();
          });
        }
      };
    }

    // Wait until all directive and route-related templates are downloaded and
    // compiled. The $templateRequest.totalPendingRequests variable keeps track of
    // all of the remote templates being currently downloaded. If there are no
    // templates currently downloading then the watcher will still fire anyway.
    var deregisterWatch = $rootScope.$watch(
      function() { return $templateRequest.totalPendingRequests === 0; },
      function(isEmpty) {
        if (!isEmpty) return;
        deregisterWatch();

        // Now that all templates have been downloaded, $animate will wait until
        // the post digest queue is empty before enabling animations. By having two
        // calls to $postDigest calls we can ensure that the flag is enabled at the
        // very end of the post digest queue. Since all of the animations in $animate
        // use $postDigest, it's important that the code below executes at the end.
        // This basically means that the page is fully downloaded and compiled before
        // any animations are triggered.
        $rootScope.$$postDigest(function() {
          $rootScope.$$postDigest(function() {
            // we check for null directly in the event that the application already called
            // .enabled() with whatever arguments that it provided it with
            if (animationsEnabled === null) {
              animationsEnabled = true;
            }
          });
        });
      }
    );

    var callbackRegistry = {};

    // remember that the classNameFilter is set during the provider/config
    // stage therefore we can optimize here and setup a helper function
    var classNameFilter = $animateProvider.classNameFilter();
    var isAnimatableClassName = !classNameFilter
              ? function() { return true; }
              : function(className) {
                return classNameFilter.test(className);
              };

    var applyAnimationClasses = applyAnimationClassesFactory($$jqLite);

    function normalizeAnimationOptions(element, options) {
      return mergeAnimationOptions(element, options, {});
    }

    function findCallbacks(parent, element, event) {
      var targetNode = getDomNode(element);
      var targetParentNode = getDomNode(parent);

      var matches = [];
      var entries = callbackRegistry[event];
      if (entries) {
        forEach(entries, function(entry) {
          if (entry.node.contains(targetNode)) {
            matches.push(entry.callback);
          } else if (event === 'leave' && entry.node.contains(targetParentNode)) {
            matches.push(entry.callback);
          }
        });
      }

      return matches;
    }

    return {
      on: function(event, container, callback) {
        var node = extractElementNode(container);
        callbackRegistry[event] = callbackRegistry[event] || [];
        callbackRegistry[event].push({
          node: node,
          callback: callback
        });
      },

      off: function(event, container, callback) {
        var entries = callbackRegistry[event];
        if (!entries) return;

        callbackRegistry[event] = arguments.length === 1
            ? null
            : filterFromRegistry(entries, container, callback);

        function filterFromRegistry(list, matchContainer, matchCallback) {
          var containerNode = extractElementNode(matchContainer);
          return list.filter(function(entry) {
            var isMatch = entry.node === containerNode &&
                            (!matchCallback || entry.callback === matchCallback);
            return !isMatch;
          });
        }
      },

      pin: function(element, parentElement) {
        assertArg(isElement(element), 'element', 'not an element');
        assertArg(isElement(parentElement), 'parentElement', 'not an element');
        element.data(NG_ANIMATE_PIN_DATA, parentElement);
      },

      push: function(element, event, options, domOperation) {
        options = options || {};
        options.domOperation = domOperation;
        return queueAnimation(element, event, options);
      },

      // this method has four signatures:
      //  () - global getter
      //  (bool) - global setter
      //  (element) - element getter
      //  (element, bool) - element setter<F37>
      enabled: function(element, bool) {
        var argCount = arguments.length;

        if (argCount === 0) {
          // () - Global getter
          bool = !!animationsEnabled;
        } else {
          var hasElement = isElement(element);

          if (!hasElement) {
            // (bool) - Global setter
            bool = animationsEnabled = !!element;
          } else {
            var node = getDomNode(element);
            var recordExists = disabledElementsLookup.get(node);

            if (argCount === 1) {
              // (element) - Element getter
              bool = !recordExists;
            } else {
              // (element, bool) - Element setter
              bool = !!bool;
              if (!bool) {
                disabledElementsLookup.put(node, true);
              } else if (recordExists) {
                disabledElementsLookup.remove(node);
              }
            }
          }
        }

        return bool;
      }
    };

    function queueAnimation(element, event, options) {
      var node, parent;
      element = stripCommentsFromElement(element);
      if (element) {
        node = getDomNode(element);
        parent = element.parent();
      }

      options = prepareAnimationOptions(options);

      // we create a fake runner with a working promise.
      // These methods will become available after the digest has passed
      var runner = new $$AnimateRunner();

      // this is used to trigger callbacks in postDigest mode
      var runInNextPostDigestOrNow = postDigestTaskFactory();

      if (isArray(options.addClass)) {
        options.addClass = options.addClass.join(' ');
      }

      if (options.addClass && !isString(options.addClass)) {
        options.addClass = null;
      }

      if (isArray(options.removeClass)) {
        options.removeClass = options.removeClass.join(' ');
      }

      if (options.removeClass && !isString(options.removeClass)) {
        options.removeClass = null;
      }

      if (options.from && !isObject(options.from)) {
        options.from = null;
      }

      if (options.to && !isObject(options.to)) {
        options.to = null;
      }

      // there are situations where a directive issues an animation for
      // a jqLite wrapper that contains only comment nodes... If this
      // happens then there is no way we can perform an animation
      if (!node) {
        close();
        return runner;
      }

      var className = [node.className, options.addClass, options.removeClass].join(' ');
      if (!isAnimatableClassName(className)) {
        close();
        return runner;
      }

      var isStructural = ['enter', 'move', 'leave'].indexOf(event) >= 0;

      // this is a hard disable of all animations for the application or on
      // the element itself, therefore  there is no need to continue further
      // past this point if not enabled
      var skipAnimations = !animationsEnabled || disabledElementsLookup.get(node);
      var existingAnimation = (!skipAnimations && activeAnimationsLookup.get(node)) || {};
      var hasExistingAnimation = !!existingAnimation.state;

      // there is no point in traversing the same collection of parent ancestors if a followup
      // animation will be run on the same element that already did all that checking work
      if (!skipAnimations && (!hasExistingAnimation || existingAnimation.state != PRE_DIGEST_STATE)) {
        skipAnimations = !areAnimationsAllowed(element, parent, event);
      }

      if (skipAnimations) {
        close();
        return runner;
      }

      if (isStructural) {
        closeChildAnimations(element);
      }

      var newAnimation = {
        structural: isStructural,
        element: element,
        event: event,
        close: close,
        options: options,
        runner: runner
      };

      if (hasExistingAnimation) {
        var skipAnimationFlag = isAllowed('skip', element, newAnimation, existingAnimation);
        if (skipAnimationFlag) {
          if (existingAnimation.state === RUNNING_STATE) {
            close();
            return runner;
          } else {
            mergeAnimationOptions(element, existingAnimation.options, options);
            return existingAnimation.runner;
          }
        }

        var cancelAnimationFlag = isAllowed('cancel', element, newAnimation, existingAnimation);
        if (cancelAnimationFlag) {
          if (existingAnimation.state === RUNNING_STATE) {
            // this will end the animation right away and it is safe
            // to do so since the animation is already running and the
            // runner callback code will run in async
            existingAnimation.runner.end();
          } else if (existingAnimation.structural) {
            // this means that the animation is queued into a digest, but
            // hasn't started yet. Therefore it is safe to run the close
            // method which will call the runner methods in async.
            existingAnimation.close();
          } else {
            // this will merge the new animation options into existing animation options
            mergeAnimationOptions(element, existingAnimation.options, newAnimation.options);
            return existingAnimation.runner;
          }
        } else {
          // a joined animation means that this animation will take over the existing one
          // so an example would involve a leave animation taking over an enter. Then when
          // the postDigest kicks in the enter will be ignored.
          var joinAnimationFlag = isAllowed('join', element, newAnimation, existingAnimation);
          if (joinAnimationFlag && existingAnimation.state < RUNNING_STATE) {
            applyGeneratedPreparationClasses(element, isStructural ? event : null, options);

            event = newAnimation.event = existingAnimation.event;
            options = mergeAnimationOptions(element, existingAnimation.options, newAnimation.options);

            //we return the same runner since only the option values of this animation will
            //be fed into the `existingAnimation`.
            return existingAnimation.runner;
          }
        }
      } else {
        // normalization in this case means that it removes redundant CSS classes that
        // already exist (addClass) or do not exist (removeClass) on the element
        normalizeAnimationOptions(element, options);
      }

      // when the options are merged and cleaned up we may end up not having to do
      // an animation at all, therefore we should check this before issuing a post
      // digest callback. Structural animations will always run no matter what.
      var isValidAnimation = newAnimation.structural;
      if (!isValidAnimation) {
        // animate (from/to) can be quickly checked first, otherwise we check if any classes are present
        isValidAnimation = (newAnimation.event === 'animate' && Object.keys(newAnimation.options.to || {}).length > 0)
                            || hasAnimationClasses(newAnimation.options);
      }

      if (!isValidAnimation) {
        close();
        clearElementAnimationState(element);
        return runner;
      }

      // the counter keeps track of cancelled animations
      var counter = (existingAnimation.counter || 0) + 1;
      newAnimation.counter = counter;

      markElementAnimationState(element, PRE_DIGEST_STATE, newAnimation);

      $rootScope.$$postDigest(function() {
        var animationDetails = activeAnimationsLookup.get(node);
        var animationCancelled = !animationDetails;
        animationDetails = animationDetails || {};

        // if addClass/removeClass is called before something like enter then the
        // registered parent element may not be present. The code below will ensure
        // that a final value for parent element is obtained
        var parentElement = element.parent() || [];

        // animate/structural/class-based animations all have requirements. Otherwise there
        // is no point in performing an animation. The parent node must also be set.
        var isValidAnimation = parentElement.length > 0
                                && (animationDetails.event === 'animate'
                                    || animationDetails.structural
                                    || hasAnimationClasses(animationDetails.options));

        // this means that the previous animation was cancelled
        // even if the follow-up animation is the same event
        if (animationCancelled || animationDetails.counter !== counter || !isValidAnimation) {
          // if another animation did not take over then we need
          // to make sure that the domOperation and options are
          // handled accordingly
          if (animationCancelled) {
            applyAnimationClasses(element, options);
            applyAnimationStyles(element, options);
          }

          // if the event changed from something like enter to leave then we do
          // it, otherwise if it's the same then the end result will be the same too
          if (animationCancelled || (isStructural && animationDetails.event !== event)) {
            options.domOperation();
            runner.end();
          }

          // in the event that the element animation was not cancelled or a follow-up animation
          // isn't allowed to animate from here then we need to clear the state of the element
          // so that any future animations won't read the expired animation data.
          if (!isValidAnimation) {
            clearElementAnimationState(element);
          }

          return;
        }

        // this combined multiple class to addClass / removeClass into a setClass event
        // so long as a structural event did not take over the animation
        event = !animationDetails.structural && hasAnimationClasses(animationDetails.options, true)
            ? 'setClass'
            : animationDetails.event;

        markElementAnimationState(element, RUNNING_STATE);
        var realRunner = $$animation(element, event, animationDetails.options);

        realRunner.done(function(status) {
          close(!status);
          var animationDetails = activeAnimationsLookup.get(node);
          if (animationDetails && animationDetails.counter === counter) {
            clearElementAnimationState(getDomNode(element));
          }
          notifyProgress(runner, event, 'close', {});
        });

        // this will update the runner's flow-control events based on
        // the `realRunner` object.
        runner.setHost(realRunner);
        notifyProgress(runner, event, 'start', {});
      });

      return runner;

      function notifyProgress(runner, event, phase, data) {
        runInNextPostDigestOrNow(function() {
          var callbacks = findCallbacks(parent, element, event);
          if (callbacks.length) {
            // do not optimize this call here to RAF because
            // we don't know how heavy the callback code here will
            // be and if this code is buffered then this can
            // lead to a performance regression.
            $$rAF(function() {
              forEach(callbacks, function(callback) {
                callback(element, phase, data);
              });
            });
          }
        });
        runner.progress(event, phase, data);
      }

      function close(reject) { // jshint ignore:line
        clearGeneratedClasses(element, options);
        applyAnimationClasses(element, options);
        applyAnimationStyles(element, options);
        options.domOperation();
        runner.complete(!reject);
      }
    }

    function closeChildAnimations(element) {
      var node = getDomNode(element);
      var children = node.querySelectorAll('[' + NG_ANIMATE_ATTR_NAME + ']');
      forEach(children, function(child) {
        var state = parseInt(child.getAttribute(NG_ANIMATE_ATTR_NAME));
        var animationDetails = activeAnimationsLookup.get(child);
        switch (state) {
          case RUNNING_STATE:
            animationDetails.runner.end();
            /* falls through */
          case PRE_DIGEST_STATE:
            if (animationDetails) {
              activeAnimationsLookup.remove(child);
            }
            break;
        }
      });
    }

    function clearElementAnimationState(element) {
      var node = getDomNode(element);
      node.removeAttribute(NG_ANIMATE_ATTR_NAME);
      activeAnimationsLookup.remove(node);
    }

    function isMatchingElement(nodeOrElmA, nodeOrElmB) {
      return getDomNode(nodeOrElmA) === getDomNode(nodeOrElmB);
    }

    function areAnimationsAllowed(element, parentElement, event) {
      var bodyElement = jqLite($document[0].body);
      var bodyElementDetected = isMatchingElement(element, bodyElement) || element[0].nodeName === 'HTML';
      var rootElementDetected = isMatchingElement(element, $rootElement);
      var parentAnimationDetected = false;
      var animateChildren;

      var parentHost = element.data(NG_ANIMATE_PIN_DATA);
      if (parentHost) {
        parentElement = parentHost;
      }

      while (parentElement && parentElement.length) {
        if (!rootElementDetected) {
          // angular doesn't want to attempt to animate elements outside of the application
          // therefore we need to ensure that the rootElement is an ancestor of the current element
          rootElementDetected = isMatchingElement(parentElement, $rootElement);
        }

        var parentNode = parentElement[0];
        if (parentNode.nodeType !== ELEMENT_NODE) {
          // no point in inspecting the #document element
          break;
        }

        var details = activeAnimationsLookup.get(parentNode) || {};
        // either an enter, leave or move animation will commence
        // therefore we can't allow any animations to take place
        // but if a parent animation is class-based then that's ok
        if (!parentAnimationDetected) {
          parentAnimationDetected = details.structural || disabledElementsLookup.get(parentNode);
        }

        if (isUndefined(animateChildren) || animateChildren === true) {
          var value = parentElement.data(NG_ANIMATE_CHILDREN_DATA);
          if (isDefined(value)) {
            animateChildren = value;
          }
        }

        // there is no need to continue traversing at this point
        if (parentAnimationDetected && animateChildren === false) break;

        if (!rootElementDetected) {
          // angular doesn't want to attempt to animate elements outside of the application
          // therefore we need to ensure that the rootElement is an ancestor of the current element
          rootElementDetected = isMatchingElement(parentElement, $rootElement);
          if (!rootElementDetected) {
            parentHost = parentElement.data(NG_ANIMATE_PIN_DATA);
            if (parentHost) {
              parentElement = parentHost;
            }
          }
        }

        if (!bodyElementDetected) {
          // we also need to ensure that the element is or will be apart of the body element
          // otherwise it is pointless to even issue an animation to be rendered
          bodyElementDetected = isMatchingElement(parentElement, bodyElement);
        }

        parentElement = parentElement.parent();
      }

      var allowAnimation = !parentAnimationDetected || animateChildren;
      return allowAnimation && rootElementDetected && bodyElementDetected;
    }

    function markElementAnimationState(element, state, details) {
      details = details || {};
      details.state = state;

      var node = getDomNode(element);
      node.setAttribute(NG_ANIMATE_ATTR_NAME, state);

      var oldValue = activeAnimationsLookup.get(node);
      var newValue = oldValue
          ? extend(oldValue, details)
          : details;
      activeAnimationsLookup.put(node, newValue);
    }
  }];
}];