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Unified Diff: pkg/template_binding/lib/js/observe.js

Issue 558673004: update polymer js to 0.4.0 (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: review updates Created 6 years, 3 months ago
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Index: pkg/template_binding/lib/js/observe.js
diff --git a/pkg/template_binding/lib/js/observe.js b/pkg/template_binding/lib/js/observe.js
new file mode 100644
index 0000000000000000000000000000000000000000..240e25deb472db7fd04232856fe9c4c4db74b0e8
--- /dev/null
+++ b/pkg/template_binding/lib/js/observe.js
@@ -0,0 +1,1727 @@
+// Copyright 2012 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+(function(global) {
+ 'use strict';
+
+ var testingExposeCycleCount = global.testingExposeCycleCount;
+
+ // Detect and do basic sanity checking on Object/Array.observe.
+ function detectObjectObserve() {
+ if (typeof Object.observe !== 'function' ||
+ typeof Array.observe !== 'function') {
+ return false;
+ }
+
+ var records = [];
+
+ function callback(recs) {
+ records = recs;
+ }
+
+ var test = {};
+ var arr = [];
+ Object.observe(test, callback);
+ Array.observe(arr, callback);
+ test.id = 1;
+ test.id = 2;
+ delete test.id;
+ arr.push(1, 2);
+ arr.length = 0;
+
+ Object.deliverChangeRecords(callback);
+ if (records.length !== 5)
+ return false;
+
+ if (records[0].type != 'add' ||
+ records[1].type != 'update' ||
+ records[2].type != 'delete' ||
+ records[3].type != 'splice' ||
+ records[4].type != 'splice') {
+ return false;
+ }
+
+ Object.unobserve(test, callback);
+ Array.unobserve(arr, callback);
+
+ return true;
+ }
+
+ var hasObserve = detectObjectObserve();
+
+ function detectEval() {
+ // Don't test for eval if we're running in a Chrome App environment.
+ // We check for APIs set that only exist in a Chrome App context.
+ if (typeof chrome !== 'undefined' && chrome.app && chrome.app.runtime) {
+ return false;
+ }
+
+ // Firefox OS Apps do not allow eval. This feature detection is very hacky
+ // but even if some other platform adds support for this function this code
+ // will continue to work.
+ if (navigator.getDeviceStorage) {
+ return false;
+ }
+
+ try {
+ var f = new Function('', 'return true;');
+ return f();
+ } catch (ex) {
+ return false;
+ }
+ }
+
+ var hasEval = detectEval();
+
+ function isIndex(s) {
+ return +s === s >>> 0;
+ }
+
+ function toNumber(s) {
+ return +s;
+ }
+
+ function isObject(obj) {
+ return obj === Object(obj);
+ }
+
+ var numberIsNaN = global.Number.isNaN || function(value) {
+ return typeof value === 'number' && global.isNaN(value);
+ }
+
+ function areSameValue(left, right) {
+ if (left === right)
+ return left !== 0 || 1 / left === 1 / right;
+ if (numberIsNaN(left) && numberIsNaN(right))
+ return true;
+
+ return left !== left && right !== right;
+ }
+
+ var createObject = ('__proto__' in {}) ?
+ function(obj) { return obj; } :
+ function(obj) {
+ var proto = obj.__proto__;
+ if (!proto)
+ return obj;
+ var newObject = Object.create(proto);
+ Object.getOwnPropertyNames(obj).forEach(function(name) {
+ Object.defineProperty(newObject, name,
+ Object.getOwnPropertyDescriptor(obj, name));
+ });
+ return newObject;
+ };
+
+ var identStart = '[\$_a-zA-Z]';
+ var identPart = '[\$_a-zA-Z0-9]';
+ var identRegExp = new RegExp('^' + identStart + '+' + identPart + '*' + '$');
+
+ function getPathCharType(char) {
+ if (char === undefined)
+ return 'eof';
+
+ var code = char.charCodeAt(0);
+
+ switch(code) {
+ case 0x5B: // [
+ case 0x5D: // ]
+ case 0x2E: // .
+ case 0x22: // "
+ case 0x27: // '
+ case 0x30: // 0
+ return char;
+
+ case 0x5F: // _
+ case 0x24: // $
+ return 'ident';
+
+ case 0x20: // Space
+ case 0x09: // Tab
+ case 0x0A: // Newline
+ case 0x0D: // Return
+ case 0xA0: // No-break space
+ case 0xFEFF: // Byte Order Mark
+ case 0x2028: // Line Separator
+ case 0x2029: // Paragraph Separator
+ return 'ws';
+ }
+
+ // a-z, A-Z
+ if ((0x61 <= code && code <= 0x7A) || (0x41 <= code && code <= 0x5A))
+ return 'ident';
+
+ // 1-9
+ if (0x31 <= code && code <= 0x39)
+ return 'number';
+
+ return 'else';
+ }
+
+ var pathStateMachine = {
+ 'beforePath': {
+ 'ws': ['beforePath'],
+ 'ident': ['inIdent', 'append'],
+ '[': ['beforeElement'],
+ 'eof': ['afterPath']
+ },
+
+ 'inPath': {
+ 'ws': ['inPath'],
+ '.': ['beforeIdent'],
+ '[': ['beforeElement'],
+ 'eof': ['afterPath']
+ },
+
+ 'beforeIdent': {
+ 'ws': ['beforeIdent'],
+ 'ident': ['inIdent', 'append']
+ },
+
+ 'inIdent': {
+ 'ident': ['inIdent', 'append'],
+ '0': ['inIdent', 'append'],
+ 'number': ['inIdent', 'append'],
+ 'ws': ['inPath', 'push'],
+ '.': ['beforeIdent', 'push'],
+ '[': ['beforeElement', 'push'],
+ 'eof': ['afterPath', 'push']
+ },
+
+ 'beforeElement': {
+ 'ws': ['beforeElement'],
+ '0': ['afterZero', 'append'],
+ 'number': ['inIndex', 'append'],
+ "'": ['inSingleQuote', 'append', ''],
+ '"': ['inDoubleQuote', 'append', '']
+ },
+
+ 'afterZero': {
+ 'ws': ['afterElement', 'push'],
+ ']': ['inPath', 'push']
+ },
+
+ 'inIndex': {
+ '0': ['inIndex', 'append'],
+ 'number': ['inIndex', 'append'],
+ 'ws': ['afterElement'],
+ ']': ['inPath', 'push']
+ },
+
+ 'inSingleQuote': {
+ "'": ['afterElement'],
+ 'eof': ['error'],
+ 'else': ['inSingleQuote', 'append']
+ },
+
+ 'inDoubleQuote': {
+ '"': ['afterElement'],
+ 'eof': ['error'],
+ 'else': ['inDoubleQuote', 'append']
+ },
+
+ 'afterElement': {
+ 'ws': ['afterElement'],
+ ']': ['inPath', 'push']
+ }
+ }
+
+ function noop() {}
+
+ function parsePath(path) {
+ var keys = [];
+ var index = -1;
+ var c, newChar, key, type, transition, action, typeMap, mode = 'beforePath';
+
+ var actions = {
+ push: function() {
+ if (key === undefined)
+ return;
+
+ keys.push(key);
+ key = undefined;
+ },
+
+ append: function() {
+ if (key === undefined)
+ key = newChar
+ else
+ key += newChar;
+ }
+ };
+
+ function maybeUnescapeQuote() {
+ if (index >= path.length)
+ return;
+
+ var nextChar = path[index + 1];
+ if ((mode == 'inSingleQuote' && nextChar == "'") ||
+ (mode == 'inDoubleQuote' && nextChar == '"')) {
+ index++;
+ newChar = nextChar;
+ actions.append();
+ return true;
+ }
+ }
+
+ while (mode) {
+ index++;
+ c = path[index];
+
+ if (c == '\\' && maybeUnescapeQuote(mode))
+ continue;
+
+ type = getPathCharType(c);
+ typeMap = pathStateMachine[mode];
+ transition = typeMap[type] || typeMap['else'] || 'error';
+
+ if (transition == 'error')
+ return; // parse error;
+
+ mode = transition[0];
+ action = actions[transition[1]] || noop;
+ newChar = transition[2] === undefined ? c : transition[2];
+ action();
+
+ if (mode === 'afterPath') {
+ return keys;
+ }
+ }
+
+ return; // parse error
+ }
+
+ function isIdent(s) {
+ return identRegExp.test(s);
+ }
+
+ var constructorIsPrivate = {};
+
+ function Path(parts, privateToken) {
+ if (privateToken !== constructorIsPrivate)
+ throw Error('Use Path.get to retrieve path objects');
+
+ for (var i = 0; i < parts.length; i++) {
+ this.push(String(parts[i]));
+ }
+
+ if (hasEval && this.length) {
+ this.getValueFrom = this.compiledGetValueFromFn();
+ }
+ }
+
+ // TODO(rafaelw): Make simple LRU cache
+ var pathCache = {};
+
+ function getPath(pathString) {
+ if (pathString instanceof Path)
+ return pathString;
+
+ if (pathString == null || pathString.length == 0)
+ pathString = '';
+
+ if (typeof pathString != 'string') {
+ if (isIndex(pathString.length)) {
+ // Constructed with array-like (pre-parsed) keys
+ return new Path(pathString, constructorIsPrivate);
+ }
+
+ pathString = String(pathString);
+ }
+
+ var path = pathCache[pathString];
+ if (path)
+ return path;
+
+ var parts = parsePath(pathString);
+ if (!parts)
+ return invalidPath;
+
+ var path = new Path(parts, constructorIsPrivate);
+ pathCache[pathString] = path;
+ return path;
+ }
+
+ Path.get = getPath;
+
+ function formatAccessor(key) {
+ if (isIndex(key)) {
+ return '[' + key + ']';
+ } else {
+ return '["' + key.replace(/"/g, '\\"') + '"]';
+ }
+ }
+
+ Path.prototype = createObject({
+ __proto__: [],
+ valid: true,
+
+ toString: function() {
+ var pathString = '';
+ for (var i = 0; i < this.length; i++) {
+ var key = this[i];
+ if (isIdent(key)) {
+ pathString += i ? '.' + key : key;
+ } else {
+ pathString += formatAccessor(key);
+ }
+ }
+
+ return pathString;
+ },
+
+ getValueFrom: function(obj, directObserver) {
+ for (var i = 0; i < this.length; i++) {
+ if (obj == null)
+ return;
+ obj = obj[this[i]];
+ }
+ return obj;
+ },
+
+ iterateObjects: function(obj, observe) {
+ for (var i = 0; i < this.length; i++) {
+ if (i)
+ obj = obj[this[i - 1]];
+ if (!isObject(obj))
+ return;
+ observe(obj, this[0]);
+ }
+ },
+
+ compiledGetValueFromFn: function() {
+ var str = '';
+ var pathString = 'obj';
+ str += 'if (obj != null';
+ var i = 0;
+ var key;
+ for (; i < (this.length - 1); i++) {
+ key = this[i];
+ pathString += isIdent(key) ? '.' + key : formatAccessor(key);
+ str += ' &&\n ' + pathString + ' != null';
+ }
+ str += ')\n';
+
+ var key = this[i];
+ pathString += isIdent(key) ? '.' + key : formatAccessor(key);
+
+ str += ' return ' + pathString + ';\nelse\n return undefined;';
+ return new Function('obj', str);
+ },
+
+ setValueFrom: function(obj, value) {
+ if (!this.length)
+ return false;
+
+ for (var i = 0; i < this.length - 1; i++) {
+ if (!isObject(obj))
+ return false;
+ obj = obj[this[i]];
+ }
+
+ if (!isObject(obj))
+ return false;
+
+ obj[this[i]] = value;
+ return true;
+ }
+ });
+
+ var invalidPath = new Path('', constructorIsPrivate);
+ invalidPath.valid = false;
+ invalidPath.getValueFrom = invalidPath.setValueFrom = function() {};
+
+ var MAX_DIRTY_CHECK_CYCLES = 1000;
+
+ function dirtyCheck(observer) {
+ var cycles = 0;
+ while (cycles < MAX_DIRTY_CHECK_CYCLES && observer.check_()) {
+ cycles++;
+ }
+ if (testingExposeCycleCount)
+ global.dirtyCheckCycleCount = cycles;
+
+ return cycles > 0;
+ }
+
+ function objectIsEmpty(object) {
+ for (var prop in object)
+ return false;
+ return true;
+ }
+
+ function diffIsEmpty(diff) {
+ return objectIsEmpty(diff.added) &&
+ objectIsEmpty(diff.removed) &&
+ objectIsEmpty(diff.changed);
+ }
+
+ function diffObjectFromOldObject(object, oldObject) {
+ var added = {};
+ var removed = {};
+ var changed = {};
+
+ for (var prop in oldObject) {
+ var newValue = object[prop];
+
+ if (newValue !== undefined && newValue === oldObject[prop])
+ continue;
+
+ if (!(prop in object)) {
+ removed[prop] = undefined;
+ continue;
+ }
+
+ if (newValue !== oldObject[prop])
+ changed[prop] = newValue;
+ }
+
+ for (var prop in object) {
+ if (prop in oldObject)
+ continue;
+
+ added[prop] = object[prop];
+ }
+
+ if (Array.isArray(object) && object.length !== oldObject.length)
+ changed.length = object.length;
+
+ return {
+ added: added,
+ removed: removed,
+ changed: changed
+ };
+ }
+
+ var eomTasks = [];
+ function runEOMTasks() {
+ if (!eomTasks.length)
+ return false;
+
+ for (var i = 0; i < eomTasks.length; i++) {
+ eomTasks[i]();
+ }
+ eomTasks.length = 0;
+ return true;
+ }
+
+ var runEOM = hasObserve ? (function(){
+ var eomObj = { pingPong: true };
+ var eomRunScheduled = false;
+
+ Object.observe(eomObj, function() {
+ runEOMTasks();
+ eomRunScheduled = false;
+ });
+
+ return function(fn) {
+ eomTasks.push(fn);
+ if (!eomRunScheduled) {
+ eomRunScheduled = true;
+ eomObj.pingPong = !eomObj.pingPong;
+ }
+ };
+ })() :
+ (function() {
+ return function(fn) {
+ eomTasks.push(fn);
+ };
+ })();
+
+ var observedObjectCache = [];
+
+ function newObservedObject() {
+ var observer;
+ var object;
+ var discardRecords = false;
+ var first = true;
+
+ function callback(records) {
+ if (observer && observer.state_ === OPENED && !discardRecords)
+ observer.check_(records);
+ }
+
+ return {
+ open: function(obs) {
+ if (observer)
+ throw Error('ObservedObject in use');
+
+ if (!first)
+ Object.deliverChangeRecords(callback);
+
+ observer = obs;
+ first = false;
+ },
+ observe: function(obj, arrayObserve) {
+ object = obj;
+ if (arrayObserve)
+ Array.observe(object, callback);
+ else
+ Object.observe(object, callback);
+ },
+ deliver: function(discard) {
+ discardRecords = discard;
+ Object.deliverChangeRecords(callback);
+ discardRecords = false;
+ },
+ close: function() {
+ observer = undefined;
+ Object.unobserve(object, callback);
+ observedObjectCache.push(this);
+ }
+ };
+ }
+
+ /*
+ * The observedSet abstraction is a perf optimization which reduces the total
+ * number of Object.observe observations of a set of objects. The idea is that
+ * groups of Observers will have some object dependencies in common and this
+ * observed set ensures that each object in the transitive closure of
+ * dependencies is only observed once. The observedSet acts as a write barrier
+ * such that whenever any change comes through, all Observers are checked for
+ * changed values.
+ *
+ * Note that this optimization is explicitly moving work from setup-time to
+ * change-time.
+ *
+ * TODO(rafaelw): Implement "garbage collection". In order to move work off
+ * the critical path, when Observers are closed, their observed objects are
+ * not Object.unobserve(d). As a result, it's possible that if the observedSet
+ * is kept open, but some Observers have been closed, it could cause "leaks"
+ * (prevent otherwise collectable objects from being collected). At some
+ * point, we should implement incremental "gc" which keeps a list of
+ * observedSets which may need clean-up and does small amounts of cleanup on a
+ * timeout until all is clean.
+ */
+
+ function getObservedObject(observer, object, arrayObserve) {
+ var dir = observedObjectCache.pop() || newObservedObject();
+ dir.open(observer);
+ dir.observe(object, arrayObserve);
+ return dir;
+ }
+
+ var observedSetCache = [];
+
+ function newObservedSet() {
+ var observerCount = 0;
+ var observers = [];
+ var objects = [];
+ var rootObj;
+ var rootObjProps;
+
+ function observe(obj, prop) {
+ if (!obj)
+ return;
+
+ if (obj === rootObj)
+ rootObjProps[prop] = true;
+
+ if (objects.indexOf(obj) < 0) {
+ objects.push(obj);
+ Object.observe(obj, callback);
+ }
+
+ observe(Object.getPrototypeOf(obj), prop);
+ }
+
+ function allRootObjNonObservedProps(recs) {
+ for (var i = 0; i < recs.length; i++) {
+ var rec = recs[i];
+ if (rec.object !== rootObj ||
+ rootObjProps[rec.name] ||
+ rec.type === 'setPrototype') {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ function callback(recs) {
+ if (allRootObjNonObservedProps(recs))
+ return;
+
+ var observer;
+ for (var i = 0; i < observers.length; i++) {
+ observer = observers[i];
+ if (observer.state_ == OPENED) {
+ observer.iterateObjects_(observe);
+ }
+ }
+
+ for (var i = 0; i < observers.length; i++) {
+ observer = observers[i];
+ if (observer.state_ == OPENED) {
+ observer.check_();
+ }
+ }
+ }
+
+ var record = {
+ object: undefined,
+ objects: objects,
+ open: function(obs, object) {
+ if (!rootObj) {
+ rootObj = object;
+ rootObjProps = {};
+ }
+
+ observers.push(obs);
+ observerCount++;
+ obs.iterateObjects_(observe);
+ },
+ close: function(obs) {
+ observerCount--;
+ if (observerCount > 0) {
+ return;
+ }
+
+ for (var i = 0; i < objects.length; i++) {
+ Object.unobserve(objects[i], callback);
+ Observer.unobservedCount++;
+ }
+
+ observers.length = 0;
+ objects.length = 0;
+ rootObj = undefined;
+ rootObjProps = undefined;
+ observedSetCache.push(this);
+ }
+ };
+
+ return record;
+ }
+
+ var lastObservedSet;
+
+ function getObservedSet(observer, obj) {
+ if (!lastObservedSet || lastObservedSet.object !== obj) {
+ lastObservedSet = observedSetCache.pop() || newObservedSet();
+ lastObservedSet.object = obj;
+ }
+ lastObservedSet.open(observer, obj);
+ return lastObservedSet;
+ }
+
+ var UNOPENED = 0;
+ var OPENED = 1;
+ var CLOSED = 2;
+ var RESETTING = 3;
+
+ var nextObserverId = 1;
+
+ function Observer() {
+ this.state_ = UNOPENED;
+ this.callback_ = undefined;
+ this.target_ = undefined; // TODO(rafaelw): Should be WeakRef
+ this.directObserver_ = undefined;
+ this.value_ = undefined;
+ this.id_ = nextObserverId++;
+ }
+
+ Observer.prototype = {
+ open: function(callback, target) {
+ if (this.state_ != UNOPENED)
+ throw Error('Observer has already been opened.');
+
+ addToAll(this);
+ this.callback_ = callback;
+ this.target_ = target;
+ this.connect_();
+ this.state_ = OPENED;
+ return this.value_;
+ },
+
+ close: function() {
+ if (this.state_ != OPENED)
+ return;
+
+ removeFromAll(this);
+ this.disconnect_();
+ this.value_ = undefined;
+ this.callback_ = undefined;
+ this.target_ = undefined;
+ this.state_ = CLOSED;
+ },
+
+ deliver: function() {
+ if (this.state_ != OPENED)
+ return;
+
+ dirtyCheck(this);
+ },
+
+ report_: function(changes) {
+ try {
+ this.callback_.apply(this.target_, changes);
+ } catch (ex) {
+ Observer._errorThrownDuringCallback = true;
+ console.error('Exception caught during observer callback: ' +
+ (ex.stack || ex));
+ }
+ },
+
+ discardChanges: function() {
+ this.check_(undefined, true);
+ return this.value_;
+ }
+ }
+
+ var collectObservers = !hasObserve;
+ var allObservers;
+ Observer._allObserversCount = 0;
+
+ if (collectObservers) {
+ allObservers = [];
+ }
+
+ function addToAll(observer) {
+ Observer._allObserversCount++;
+ if (!collectObservers)
+ return;
+
+ allObservers.push(observer);
+ }
+
+ function removeFromAll(observer) {
+ Observer._allObserversCount--;
+ }
+
+ var runningMicrotaskCheckpoint = false;
+
+ var hasDebugForceFullDelivery = hasObserve && hasEval && (function() {
+ try {
+ eval('%RunMicrotasks()');
+ return true;
+ } catch (ex) {
+ return false;
+ }
+ })();
+
+ global.Platform = global.Platform || {};
+
+ global.Platform.performMicrotaskCheckpoint = function() {
+ if (runningMicrotaskCheckpoint)
+ return;
+
+ if (hasDebugForceFullDelivery) {
+ eval('%RunMicrotasks()');
+ return;
+ }
+
+ if (!collectObservers)
+ return;
+
+ runningMicrotaskCheckpoint = true;
+
+ var cycles = 0;
+ var anyChanged, toCheck;
+
+ do {
+ cycles++;
+ toCheck = allObservers;
+ allObservers = [];
+ anyChanged = false;
+
+ for (var i = 0; i < toCheck.length; i++) {
+ var observer = toCheck[i];
+ if (observer.state_ != OPENED)
+ continue;
+
+ if (observer.check_())
+ anyChanged = true;
+
+ allObservers.push(observer);
+ }
+ if (runEOMTasks())
+ anyChanged = true;
+ } while (cycles < MAX_DIRTY_CHECK_CYCLES && anyChanged);
+
+ if (testingExposeCycleCount)
+ global.dirtyCheckCycleCount = cycles;
+
+ runningMicrotaskCheckpoint = false;
+ };
+
+ if (collectObservers) {
+ global.Platform.clearObservers = function() {
+ allObservers = [];
+ };
+ }
+
+ function ObjectObserver(object) {
+ Observer.call(this);
+ this.value_ = object;
+ this.oldObject_ = undefined;
+ }
+
+ ObjectObserver.prototype = createObject({
+ __proto__: Observer.prototype,
+
+ arrayObserve: false,
+
+ connect_: function(callback, target) {
+ if (hasObserve) {
+ this.directObserver_ = getObservedObject(this, this.value_,
+ this.arrayObserve);
+ } else {
+ this.oldObject_ = this.copyObject(this.value_);
+ }
+
+ },
+
+ copyObject: function(object) {
+ var copy = Array.isArray(object) ? [] : {};
+ for (var prop in object) {
+ copy[prop] = object[prop];
+ };
+ if (Array.isArray(object))
+ copy.length = object.length;
+ return copy;
+ },
+
+ check_: function(changeRecords, skipChanges) {
+ var diff;
+ var oldValues;
+ if (hasObserve) {
+ if (!changeRecords)
+ return false;
+
+ oldValues = {};
+ diff = diffObjectFromChangeRecords(this.value_, changeRecords,
+ oldValues);
+ } else {
+ oldValues = this.oldObject_;
+ diff = diffObjectFromOldObject(this.value_, this.oldObject_);
+ }
+
+ if (diffIsEmpty(diff))
+ return false;
+
+ if (!hasObserve)
+ this.oldObject_ = this.copyObject(this.value_);
+
+ this.report_([
+ diff.added || {},
+ diff.removed || {},
+ diff.changed || {},
+ function(property) {
+ return oldValues[property];
+ }
+ ]);
+
+ return true;
+ },
+
+ disconnect_: function() {
+ if (hasObserve) {
+ this.directObserver_.close();
+ this.directObserver_ = undefined;
+ } else {
+ this.oldObject_ = undefined;
+ }
+ },
+
+ deliver: function() {
+ if (this.state_ != OPENED)
+ return;
+
+ if (hasObserve)
+ this.directObserver_.deliver(false);
+ else
+ dirtyCheck(this);
+ },
+
+ discardChanges: function() {
+ if (this.directObserver_)
+ this.directObserver_.deliver(true);
+ else
+ this.oldObject_ = this.copyObject(this.value_);
+
+ return this.value_;
+ }
+ });
+
+ function ArrayObserver(array) {
+ if (!Array.isArray(array))
+ throw Error('Provided object is not an Array');
+ ObjectObserver.call(this, array);
+ }
+
+ ArrayObserver.prototype = createObject({
+
+ __proto__: ObjectObserver.prototype,
+
+ arrayObserve: true,
+
+ copyObject: function(arr) {
+ return arr.slice();
+ },
+
+ check_: function(changeRecords) {
+ var splices;
+ if (hasObserve) {
+ if (!changeRecords)
+ return false;
+ splices = projectArraySplices(this.value_, changeRecords);
+ } else {
+ splices = calcSplices(this.value_, 0, this.value_.length,
+ this.oldObject_, 0, this.oldObject_.length);
+ }
+
+ if (!splices || !splices.length)
+ return false;
+
+ if (!hasObserve)
+ this.oldObject_ = this.copyObject(this.value_);
+
+ this.report_([splices]);
+ return true;
+ }
+ });
+
+ ArrayObserver.applySplices = function(previous, current, splices) {
+ splices.forEach(function(splice) {
+ var spliceArgs = [splice.index, splice.removed.length];
+ var addIndex = splice.index;
+ while (addIndex < splice.index + splice.addedCount) {
+ spliceArgs.push(current[addIndex]);
+ addIndex++;
+ }
+
+ Array.prototype.splice.apply(previous, spliceArgs);
+ });
+ };
+
+ function PathObserver(object, path) {
+ Observer.call(this);
+
+ this.object_ = object;
+ this.path_ = getPath(path);
+ this.directObserver_ = undefined;
+ }
+
+ PathObserver.prototype = createObject({
+ __proto__: Observer.prototype,
+
+ get path() {
+ return this.path_;
+ },
+
+ connect_: function() {
+ if (hasObserve)
+ this.directObserver_ = getObservedSet(this, this.object_);
+
+ this.check_(undefined, true);
+ },
+
+ disconnect_: function() {
+ this.value_ = undefined;
+
+ if (this.directObserver_) {
+ this.directObserver_.close(this);
+ this.directObserver_ = undefined;
+ }
+ },
+
+ iterateObjects_: function(observe) {
+ this.path_.iterateObjects(this.object_, observe);
+ },
+
+ check_: function(changeRecords, skipChanges) {
+ var oldValue = this.value_;
+ this.value_ = this.path_.getValueFrom(this.object_);
+ if (skipChanges || areSameValue(this.value_, oldValue))
+ return false;
+
+ this.report_([this.value_, oldValue, this]);
+ return true;
+ },
+
+ setValue: function(newValue) {
+ if (this.path_)
+ this.path_.setValueFrom(this.object_, newValue);
+ }
+ });
+
+ function CompoundObserver(reportChangesOnOpen) {
+ Observer.call(this);
+
+ this.reportChangesOnOpen_ = reportChangesOnOpen;
+ this.value_ = [];
+ this.directObserver_ = undefined;
+ this.observed_ = [];
+ }
+
+ var observerSentinel = {};
+
+ CompoundObserver.prototype = createObject({
+ __proto__: Observer.prototype,
+
+ connect_: function() {
+ if (hasObserve) {
+ var object;
+ var needsDirectObserver = false;
+ for (var i = 0; i < this.observed_.length; i += 2) {
+ object = this.observed_[i]
+ if (object !== observerSentinel) {
+ needsDirectObserver = true;
+ break;
+ }
+ }
+
+ if (needsDirectObserver)
+ this.directObserver_ = getObservedSet(this, object);
+ }
+
+ this.check_(undefined, !this.reportChangesOnOpen_);
+ },
+
+ disconnect_: function() {
+ for (var i = 0; i < this.observed_.length; i += 2) {
+ if (this.observed_[i] === observerSentinel)
+ this.observed_[i + 1].close();
+ }
+ this.observed_.length = 0;
+ this.value_.length = 0;
+
+ if (this.directObserver_) {
+ this.directObserver_.close(this);
+ this.directObserver_ = undefined;
+ }
+ },
+
+ addPath: function(object, path) {
+ if (this.state_ != UNOPENED && this.state_ != RESETTING)
+ throw Error('Cannot add paths once started.');
+
+ var path = getPath(path);
+ this.observed_.push(object, path);
+ if (!this.reportChangesOnOpen_)
+ return;
+ var index = this.observed_.length / 2 - 1;
+ this.value_[index] = path.getValueFrom(object);
+ },
+
+ addObserver: function(observer) {
+ if (this.state_ != UNOPENED && this.state_ != RESETTING)
+ throw Error('Cannot add observers once started.');
+
+ this.observed_.push(observerSentinel, observer);
+ if (!this.reportChangesOnOpen_)
+ return;
+ var index = this.observed_.length / 2 - 1;
+ this.value_[index] = observer.open(this.deliver, this);
+ },
+
+ startReset: function() {
+ if (this.state_ != OPENED)
+ throw Error('Can only reset while open');
+
+ this.state_ = RESETTING;
+ this.disconnect_();
+ },
+
+ finishReset: function() {
+ if (this.state_ != RESETTING)
+ throw Error('Can only finishReset after startReset');
+ this.state_ = OPENED;
+ this.connect_();
+
+ return this.value_;
+ },
+
+ iterateObjects_: function(observe) {
+ var object;
+ for (var i = 0; i < this.observed_.length; i += 2) {
+ object = this.observed_[i]
+ if (object !== observerSentinel)
+ this.observed_[i + 1].iterateObjects(object, observe)
+ }
+ },
+
+ check_: function(changeRecords, skipChanges) {
+ var oldValues;
+ for (var i = 0; i < this.observed_.length; i += 2) {
+ var object = this.observed_[i];
+ var path = this.observed_[i+1];
+ var value;
+ if (object === observerSentinel) {
+ var observable = path;
+ value = this.state_ === UNOPENED ?
+ observable.open(this.deliver, this) :
+ observable.discardChanges();
+ } else {
+ value = path.getValueFrom(object);
+ }
+
+ if (skipChanges) {
+ this.value_[i / 2] = value;
+ continue;
+ }
+
+ if (areSameValue(value, this.value_[i / 2]))
+ continue;
+
+ oldValues = oldValues || [];
+ oldValues[i / 2] = this.value_[i / 2];
+ this.value_[i / 2] = value;
+ }
+
+ if (!oldValues)
+ return false;
+
+ // TODO(rafaelw): Having observed_ as the third callback arg here is
+ // pretty lame API. Fix.
+ this.report_([this.value_, oldValues, this.observed_]);
+ return true;
+ }
+ });
+
+ function identFn(value) { return value; }
+
+ function ObserverTransform(observable, getValueFn, setValueFn,
+ dontPassThroughSet) {
+ this.callback_ = undefined;
+ this.target_ = undefined;
+ this.value_ = undefined;
+ this.observable_ = observable;
+ this.getValueFn_ = getValueFn || identFn;
+ this.setValueFn_ = setValueFn || identFn;
+ // TODO(rafaelw): This is a temporary hack. PolymerExpressions needs this
+ // at the moment because of a bug in it's dependency tracking.
+ this.dontPassThroughSet_ = dontPassThroughSet;
+ }
+
+ ObserverTransform.prototype = {
+ open: function(callback, target) {
+ this.callback_ = callback;
+ this.target_ = target;
+ this.value_ =
+ this.getValueFn_(this.observable_.open(this.observedCallback_, this));
+ return this.value_;
+ },
+
+ observedCallback_: function(value) {
+ value = this.getValueFn_(value);
+ if (areSameValue(value, this.value_))
+ return;
+ var oldValue = this.value_;
+ this.value_ = value;
+ this.callback_.call(this.target_, this.value_, oldValue);
+ },
+
+ discardChanges: function() {
+ this.value_ = this.getValueFn_(this.observable_.discardChanges());
+ return this.value_;
+ },
+
+ deliver: function() {
+ return this.observable_.deliver();
+ },
+
+ setValue: function(value) {
+ value = this.setValueFn_(value);
+ if (!this.dontPassThroughSet_ && this.observable_.setValue)
+ return this.observable_.setValue(value);
+ },
+
+ close: function() {
+ if (this.observable_)
+ this.observable_.close();
+ this.callback_ = undefined;
+ this.target_ = undefined;
+ this.observable_ = undefined;
+ this.value_ = undefined;
+ this.getValueFn_ = undefined;
+ this.setValueFn_ = undefined;
+ }
+ }
+
+ var expectedRecordTypes = {
+ add: true,
+ update: true,
+ delete: true
+ };
+
+ function diffObjectFromChangeRecords(object, changeRecords, oldValues) {
+ var added = {};
+ var removed = {};
+
+ for (var i = 0; i < changeRecords.length; i++) {
+ var record = changeRecords[i];
+ if (!expectedRecordTypes[record.type]) {
+ console.error('Unknown changeRecord type: ' + record.type);
+ console.error(record);
+ continue;
+ }
+
+ if (!(record.name in oldValues))
+ oldValues[record.name] = record.oldValue;
+
+ if (record.type == 'update')
+ continue;
+
+ if (record.type == 'add') {
+ if (record.name in removed)
+ delete removed[record.name];
+ else
+ added[record.name] = true;
+
+ continue;
+ }
+
+ // type = 'delete'
+ if (record.name in added) {
+ delete added[record.name];
+ delete oldValues[record.name];
+ } else {
+ removed[record.name] = true;
+ }
+ }
+
+ for (var prop in added)
+ added[prop] = object[prop];
+
+ for (var prop in removed)
+ removed[prop] = undefined;
+
+ var changed = {};
+ for (var prop in oldValues) {
+ if (prop in added || prop in removed)
+ continue;
+
+ var newValue = object[prop];
+ if (oldValues[prop] !== newValue)
+ changed[prop] = newValue;
+ }
+
+ return {
+ added: added,
+ removed: removed,
+ changed: changed
+ };
+ }
+
+ function newSplice(index, removed, addedCount) {
+ return {
+ index: index,
+ removed: removed,
+ addedCount: addedCount
+ };
+ }
+
+ var EDIT_LEAVE = 0;
+ var EDIT_UPDATE = 1;
+ var EDIT_ADD = 2;
+ var EDIT_DELETE = 3;
+
+ function ArraySplice() {}
+
+ ArraySplice.prototype = {
+
+ // Note: This function is *based* on the computation of the Levenshtein
+ // "edit" distance. The one change is that "updates" are treated as two
+ // edits - not one. With Array splices, an update is really a delete
+ // followed by an add. By retaining this, we optimize for "keeping" the
+ // maximum array items in the original array. For example:
+ //
+ // 'xxxx123' -> '123yyyy'
+ //
+ // With 1-edit updates, the shortest path would be just to update all seven
+ // characters. With 2-edit updates, we delete 4, leave 3, and add 4. This
+ // leaves the substring '123' intact.
+ calcEditDistances: function(current, currentStart, currentEnd,
+ old, oldStart, oldEnd) {
+ // "Deletion" columns
+ var rowCount = oldEnd - oldStart + 1;
+ var columnCount = currentEnd - currentStart + 1;
+ var distances = new Array(rowCount);
+
+ // "Addition" rows. Initialize null column.
+ for (var i = 0; i < rowCount; i++) {
+ distances[i] = new Array(columnCount);
+ distances[i][0] = i;
+ }
+
+ // Initialize null row
+ for (var j = 0; j < columnCount; j++)
+ distances[0][j] = j;
+
+ for (var i = 1; i < rowCount; i++) {
+ for (var j = 1; j < columnCount; j++) {
+ if (this.equals(current[currentStart + j - 1], old[oldStart + i - 1]))
+ distances[i][j] = distances[i - 1][j - 1];
+ else {
+ var north = distances[i - 1][j] + 1;
+ var west = distances[i][j - 1] + 1;
+ distances[i][j] = north < west ? north : west;
+ }
+ }
+ }
+
+ return distances;
+ },
+
+ // This starts at the final weight, and walks "backward" by finding
+ // the minimum previous weight recursively until the origin of the weight
+ // matrix.
+ spliceOperationsFromEditDistances: function(distances) {
+ var i = distances.length - 1;
+ var j = distances[0].length - 1;
+ var current = distances[i][j];
+ var edits = [];
+ while (i > 0 || j > 0) {
+ if (i == 0) {
+ edits.push(EDIT_ADD);
+ j--;
+ continue;
+ }
+ if (j == 0) {
+ edits.push(EDIT_DELETE);
+ i--;
+ continue;
+ }
+ var northWest = distances[i - 1][j - 1];
+ var west = distances[i - 1][j];
+ var north = distances[i][j - 1];
+
+ var min;
+ if (west < north)
+ min = west < northWest ? west : northWest;
+ else
+ min = north < northWest ? north : northWest;
+
+ if (min == northWest) {
+ if (northWest == current) {
+ edits.push(EDIT_LEAVE);
+ } else {
+ edits.push(EDIT_UPDATE);
+ current = northWest;
+ }
+ i--;
+ j--;
+ } else if (min == west) {
+ edits.push(EDIT_DELETE);
+ i--;
+ current = west;
+ } else {
+ edits.push(EDIT_ADD);
+ j--;
+ current = north;
+ }
+ }
+
+ edits.reverse();
+ return edits;
+ },
+
+ /**
+ * Splice Projection functions:
+ *
+ * A splice map is a representation of how a previous array of items
+ * was transformed into a new array of items. Conceptually it is a list of
+ * tuples of
+ *
+ * <index, removed, addedCount>
+ *
+ * which are kept in ascending index order of. The tuple represents that at
+ * the |index|, |removed| sequence of items were removed, and counting forward
+ * from |index|, |addedCount| items were added.
+ */
+
+ /**
+ * Lacking individual splice mutation information, the minimal set of
+ * splices can be synthesized given the previous state and final state of an
+ * array. The basic approach is to calculate the edit distance matrix and
+ * choose the shortest path through it.
+ *
+ * Complexity: O(l * p)
+ * l: The length of the current array
+ * p: The length of the old array
+ */
+ calcSplices: function(current, currentStart, currentEnd,
+ old, oldStart, oldEnd) {
+ var prefixCount = 0;
+ var suffixCount = 0;
+
+ var minLength = Math.min(currentEnd - currentStart, oldEnd - oldStart);
+ if (currentStart == 0 && oldStart == 0)
+ prefixCount = this.sharedPrefix(current, old, minLength);
+
+ if (currentEnd == current.length && oldEnd == old.length)
+ suffixCount = this.sharedSuffix(current, old, minLength - prefixCount);
+
+ currentStart += prefixCount;
+ oldStart += prefixCount;
+ currentEnd -= suffixCount;
+ oldEnd -= suffixCount;
+
+ if (currentEnd - currentStart == 0 && oldEnd - oldStart == 0)
+ return [];
+
+ if (currentStart == currentEnd) {
+ var splice = newSplice(currentStart, [], 0);
+ while (oldStart < oldEnd)
+ splice.removed.push(old[oldStart++]);
+
+ return [ splice ];
+ } else if (oldStart == oldEnd)
+ return [ newSplice(currentStart, [], currentEnd - currentStart) ];
+
+ var ops = this.spliceOperationsFromEditDistances(
+ this.calcEditDistances(current, currentStart, currentEnd,
+ old, oldStart, oldEnd));
+
+ var splice = undefined;
+ var splices = [];
+ var index = currentStart;
+ var oldIndex = oldStart;
+ for (var i = 0; i < ops.length; i++) {
+ switch(ops[i]) {
+ case EDIT_LEAVE:
+ if (splice) {
+ splices.push(splice);
+ splice = undefined;
+ }
+
+ index++;
+ oldIndex++;
+ break;
+ case EDIT_UPDATE:
+ if (!splice)
+ splice = newSplice(index, [], 0);
+
+ splice.addedCount++;
+ index++;
+
+ splice.removed.push(old[oldIndex]);
+ oldIndex++;
+ break;
+ case EDIT_ADD:
+ if (!splice)
+ splice = newSplice(index, [], 0);
+
+ splice.addedCount++;
+ index++;
+ break;
+ case EDIT_DELETE:
+ if (!splice)
+ splice = newSplice(index, [], 0);
+
+ splice.removed.push(old[oldIndex]);
+ oldIndex++;
+ break;
+ }
+ }
+
+ if (splice) {
+ splices.push(splice);
+ }
+ return splices;
+ },
+
+ sharedPrefix: function(current, old, searchLength) {
+ for (var i = 0; i < searchLength; i++)
+ if (!this.equals(current[i], old[i]))
+ return i;
+ return searchLength;
+ },
+
+ sharedSuffix: function(current, old, searchLength) {
+ var index1 = current.length;
+ var index2 = old.length;
+ var count = 0;
+ while (count < searchLength && this.equals(current[--index1], old[--index2]))
+ count++;
+
+ return count;
+ },
+
+ calculateSplices: function(current, previous) {
+ return this.calcSplices(current, 0, current.length, previous, 0,
+ previous.length);
+ },
+
+ equals: function(currentValue, previousValue) {
+ return currentValue === previousValue;
+ }
+ };
+
+ var arraySplice = new ArraySplice();
+
+ function calcSplices(current, currentStart, currentEnd,
+ old, oldStart, oldEnd) {
+ return arraySplice.calcSplices(current, currentStart, currentEnd,
+ old, oldStart, oldEnd);
+ }
+
+ function intersect(start1, end1, start2, end2) {
+ // Disjoint
+ if (end1 < start2 || end2 < start1)
+ return -1;
+
+ // Adjacent
+ if (end1 == start2 || end2 == start1)
+ return 0;
+
+ // Non-zero intersect, span1 first
+ if (start1 < start2) {
+ if (end1 < end2)
+ return end1 - start2; // Overlap
+ else
+ return end2 - start2; // Contained
+ } else {
+ // Non-zero intersect, span2 first
+ if (end2 < end1)
+ return end2 - start1; // Overlap
+ else
+ return end1 - start1; // Contained
+ }
+ }
+
+ function mergeSplice(splices, index, removed, addedCount) {
+
+ var splice = newSplice(index, removed, addedCount);
+
+ var inserted = false;
+ var insertionOffset = 0;
+
+ for (var i = 0; i < splices.length; i++) {
+ var current = splices[i];
+ current.index += insertionOffset;
+
+ if (inserted)
+ continue;
+
+ var intersectCount = intersect(splice.index,
+ splice.index + splice.removed.length,
+ current.index,
+ current.index + current.addedCount);
+
+ if (intersectCount >= 0) {
+ // Merge the two splices
+
+ splices.splice(i, 1);
+ i--;
+
+ insertionOffset -= current.addedCount - current.removed.length;
+
+ splice.addedCount += current.addedCount - intersectCount;
+ var deleteCount = splice.removed.length +
+ current.removed.length - intersectCount;
+
+ if (!splice.addedCount && !deleteCount) {
+ // merged splice is a noop. discard.
+ inserted = true;
+ } else {
+ var removed = current.removed;
+
+ if (splice.index < current.index) {
+ // some prefix of splice.removed is prepended to current.removed.
+ var prepend = splice.removed.slice(0, current.index - splice.index);
+ Array.prototype.push.apply(prepend, removed);
+ removed = prepend;
+ }
+
+ if (splice.index + splice.removed.length > current.index + current.addedCount) {
+ // some suffix of splice.removed is appended to current.removed.
+ var append = splice.removed.slice(current.index + current.addedCount - splice.index);
+ Array.prototype.push.apply(removed, append);
+ }
+
+ splice.removed = removed;
+ if (current.index < splice.index) {
+ splice.index = current.index;
+ }
+ }
+ } else if (splice.index < current.index) {
+ // Insert splice here.
+
+ inserted = true;
+
+ splices.splice(i, 0, splice);
+ i++;
+
+ var offset = splice.addedCount - splice.removed.length
+ current.index += offset;
+ insertionOffset += offset;
+ }
+ }
+
+ if (!inserted)
+ splices.push(splice);
+ }
+
+ function createInitialSplices(array, changeRecords) {
+ var splices = [];
+
+ for (var i = 0; i < changeRecords.length; i++) {
+ var record = changeRecords[i];
+ switch(record.type) {
+ case 'splice':
+ mergeSplice(splices, record.index, record.removed.slice(), record.addedCount);
+ break;
+ case 'add':
+ case 'update':
+ case 'delete':
+ if (!isIndex(record.name))
+ continue;
+ var index = toNumber(record.name);
+ if (index < 0)
+ continue;
+ mergeSplice(splices, index, [record.oldValue], 1);
+ break;
+ default:
+ console.error('Unexpected record type: ' + JSON.stringify(record));
+ break;
+ }
+ }
+
+ return splices;
+ }
+
+ function projectArraySplices(array, changeRecords) {
+ var splices = [];
+
+ createInitialSplices(array, changeRecords).forEach(function(splice) {
+ if (splice.addedCount == 1 && splice.removed.length == 1) {
+ if (splice.removed[0] !== array[splice.index])
+ splices.push(splice);
+
+ return
+ };
+
+ splices = splices.concat(calcSplices(array, splice.index, splice.index + splice.addedCount,
+ splice.removed, 0, splice.removed.length));
+ });
+
+ return splices;
+ }
+
+ global.Observer = Observer;
+ global.Observer.runEOM_ = runEOM;
+ global.Observer.observerSentinel_ = observerSentinel; // for testing.
+ global.Observer.hasObjectObserve = hasObserve;
+ global.ArrayObserver = ArrayObserver;
+ global.ArrayObserver.calculateSplices = function(current, previous) {
+ return arraySplice.calculateSplices(current, previous);
+ };
+
+ global.ArraySplice = ArraySplice;
+ global.ObjectObserver = ObjectObserver;
+ global.PathObserver = PathObserver;
+ global.CompoundObserver = CompoundObserver;
+ global.Path = Path;
+ global.ObserverTransform = ObserverTransform;
+})(typeof global !== 'undefined' && global && typeof module !== 'undefined' && module ? global : this || window);
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