AngularJS RootScope 源码分析

this.digestTtl = function(value) {
    if (arguments.length) {
      TTL = value;
    }
    return TTL;
  };

function Scope() {
    this.$id = nextUid();
    this.$$phase = this.$parent = this.$$watchers =
                     this.$$nextSibling = this.$$prevSibling =
                     this.$$childHead = this.$$childTail = null;
    this['this'] = this.$root =  this;
    this.$$destroyed = false;
    this.$$asyncQueue = [];
    this.$$postDigestQueue = [];
    this.$$listeners = {};
    this.$$listenerCount = {};
    this.$$isolateBindings = {};
}

var $rootScope = new Scope();

return $rootScope;

$new: function(isolate) {
        var ChildScope,
            child;

        if (isolate) {
          child = new Scope();
          child.$root = this.$root;
          // ensure that there is just one async queue per $rootScope and its children
          child.$$asyncQueue = this.$$asyncQueue;
          child.$$postDigestQueue = this.$$postDigestQueue;
        } else {
          // Only create a child scope class if somebody asks for one,
          // but cache it to allow the VM to optimize lookups.
          if (!this.$$childScopeClass) {
            this.$$childScopeClass = function() {
              this.$$watchers = this.$$nextSibling =
                  this.$$childHead = this.$$childTail = null;
              this.$$listeners = {};
              this.$$listenerCount = {};
              this.$id = nextUid();
              this.$$childScopeClass = null;
            };
            this.$$childScopeClass.prototype = this;
          }
          child = new this.$$childScopeClass();
        }
        child['this'] = child;
        child.$parent = this;
        child.$$prevSibling = this.$$childTail;
        if (this.$$childHead) {
          this.$$childTail.$$nextSibling = child;
          this.$$childTail = child;
        } else {
          this.$$childHead = this.$$childTail = child;
        }
        return child;
      }

get = compileToFn(watchExp, 'watch')

$watch: function(watchExp, listener, objectEquality) {
        var scope = this,
            get = compileToFn(watchExp, 'watch'),
            array = scope.$$watchers,
            watcher = {
              fn: listener,
              last: initWatchVal,
              get: get,
              exp: watchExp,
              eq: !!objectEquality
            };

        lastDirtyWatch = null;

        // in the case user pass string, we need to compile it, do we really need this ?
        if (!isFunction(listener)) {
          var listenFn = compileToFn(listener || noop, 'listener');
          watcher.fn = function(newVal, oldVal, scope) {listenFn(scope);};
        }

        if (typeof watchExp == 'string' && get.constant) {
          var originalFn = watcher.fn;
          watcher.fn = function(newVal, oldVal, scope) {
            originalFn.call(this, newVal, oldVal, scope);
            arrayRemove(array, watcher);
          };
        }

        if (!array) {
          array = scope.$$watchers = [];
        }
        // we use unshift since we use a while loop in $digest for speed.
        // the while loop reads in reverse order.
        array.unshift(watcher);

        return function deregisterWatch() {
          arrayRemove(array, watcher);
          lastDirtyWatch = null;
        };
      }

this.$get = ['$filter', '$sniffer', '$log', function($filter, $sniffer, $log) {
    $parseOptions.csp = $sniffer.csp;

    promiseWarning = function promiseWarningFn(fullExp) {
      if (!$parseOptions.logPromiseWarnings || promiseWarningCache.hasOwnProperty(fullExp)) return;
      promiseWarningCache[fullExp] = true;
      $log.warn('[$parse] Promise found in the expression `' + fullExp + '`. ' +
          'Automatic unwrapping of promises in Angular expressions is deprecated.');
    };

    return function(exp) {
      var parsedExpression;

      switch (typeof exp) {
        case 'string':

          if (cache.hasOwnProperty(exp)) {
            return cache[exp];
          }

          var lexer = new Lexer($parseOptions);
          var parser = new Parser(lexer, $filter, $parseOptions);
          parsedExpression = parser.parse(exp, false);

          if (exp !== 'hasOwnProperty') {
            // Only cache the value if it's not going to mess up the cache object
            // This is more performant that using Object.prototype.hasOwnProperty.call
            cache[exp] = parsedExpression;
          }

          return parsedExpression;

        case 'function':
          return exp;

        default:
          return noop;
      }
    };
  }];

var lexer = new Lexer($parseOptions);
var parser = new Parser(lexer, $filter, $parseOptions);
parsedExpression = parser.parse(exp, false);

parse: function (text, json) {
    this.text = text;

    //TODO(i): strip all the obsolte json stuff from this file
    this.json = json;

    this.tokens = this.lexer.lex(text);

    console.log(this.tokens);

    if (json) {
      // The extra level of aliasing is here, just in case the lexer misses something, so that
      // we prevent any accidental execution in JSON.
      this.assignment = this.logicalOR;

      this.functionCall =
      this.fieldAccess =
      this.objectIndex =
      this.filterChain = function() {
        this.throwError('is not valid json', {text: text, index: 0});
      };
    }

    var value = json ? this.primary() : this.statements();

    if (this.tokens.length !== 0) {
      this.throwError('is an unexpected token', this.tokens[0]);
    }

    value.literal = !!value.literal;
    value.constant = !!value.constant;

    return value;
  }

lex: function (text) {
    this.text = text;

    this.index = 0;
    this.ch = undefined;
    this.lastCh = ':'; // can start regexp

    this.tokens = [];

    var token;
    var json = [];

    while (this.index < this.text.length) {
      this.ch = this.text.charAt(this.index);
      if (this.is('"\'')) {
        this.readString(this.ch);
      } else if (this.isNumber(this.ch) || this.is('.') && this.isNumber(this.peek())) {
        this.readNumber();
      } else if (this.isIdent(this.ch)) {
        this.readIdent();
        // identifiers can only be if the preceding char was a { or ,
        if (this.was('{,') && json[0] === '{' &&
            (token = this.tokens[this.tokens.length - 1])) {
          token.json = token.text.indexOf('.') === -1;
        }
      } else if (this.is('(){}[].,;:?')) {
        this.tokens.push({
          index: this.index,
          text: this.ch,
          json: (this.was(':[,') && this.is('{[')) || this.is('}]:,')
        });
        if (this.is('{[')) json.unshift(this.ch);
        if (this.is('}]')) json.shift();
        this.index++;
      } else if (this.isWhitespace(this.ch)) {
        this.index++;
        continue;
      } else {
        var ch2 = this.ch + this.peek();
        var ch3 = ch2 + this.peek(2);
        var fn = OPERATORS[this.ch];
        var fn2 = OPERATORS[ch2];
        var fn3 = OPERATORS[ch3];
        if (fn3) {
          this.tokens.push({index: this.index, text: ch3, fn: fn3});
          this.index += 3;
        } else if (fn2) {
          this.tokens.push({index: this.index, text: ch2, fn: fn2});
          this.index += 2;
        } else if (fn) {
          this.tokens.push({
            index: this.index,
            text: this.ch,
            fn: fn,
            json: (this.was('[,:') && this.is('+-'))
          });
          this.index += 1;
        } else {
          this.throwError('Unexpected next character ', this.index, this.index + 1);
        }
      }
      this.lastCh = this.ch;
    }
    return this.tokens;
  }

readNumber: function() {
    var number = '';
    var start = this.index;
    while (this.index < this.text.length) {
      var ch = lowercase(this.text.charAt(this.index));
      if (ch == '.' || this.isNumber(ch)) {
        number += ch;
      } else {
        var peekCh = this.peek();
        if (ch == 'e' && this.isExpOperator(peekCh)) {
          number += ch;
        } else if (this.isExpOperator(ch) &&
            peekCh && this.isNumber(peekCh) &&
            number.charAt(number.length - 1) == 'e') {
          number += ch;
        } else if (this.isExpOperator(ch) &&
            (!peekCh || !this.isNumber(peekCh)) &&
            number.charAt(number.length - 1) == 'e') {
          this.throwError('Invalid exponent');
        } else {
          break;
        }
      }
      this.index++;
    }
    number = 1 * number;
    this.tokens.push({
      index: start,
      text: number,
      json: true,
      fn: function() { return number; }
    });
  }

'+':function(self, locals, a,b){
      a=a(self, locals); b=b(self, locals);
      if (isDefined(a)) {
        if (isDefined(b)) {
          return a + b;
        }
        return a;
      }
      return isDefined(b)?b:undefined;}

var value = json ? this.primary() : this.statements();

 statements: function() {
    var statements = [];
    while (true) {
      if (this.tokens.length > 0 && !this.peek('}', ')', ';', ']'))
        statements.push(this.filterChain());
      if (!this.expect(';')) {
        // optimize for the common case where there is only one statement.
        // TODO(size): maybe we should not support multiple statements?
        return (statements.length === 1)
            ? statements[0]
            : function(self, locals) {
                var value;
                for (var i = 0; i < statements.length; i++) {
                  var statement = statements[i];
                  if (statement) {
                    value = statement(self, locals);
                  }
                }
                return value;
              };
      }
    }
  }

peek: function(e1, e2, e3, e4) {
    if (this.tokens.length > 0) {
      var token = this.tokens[0];
      var t = token.text;
      if (t === e1 || t === e2 || t === e3 || t === e4 ||
          (!e1 && !e2 && !e3 && !e4)) {
        return token;
      }
    }
    return false;
  },

  expect: function(e1, e2, e3, e4){
    var token = this.peek(e1, e2, e3, e4);
    if (token) {
      if (this.json && !token.json) {
        this.throwError('is not valid json', token);
      }
      this.tokens.shift();
      return token;
    }
    return false;
  }

 additive: function() {
    var left = this.multiplicative();
    var token;
    while ((token = this.expect('+','-'))) {
      left = this.binaryFn(left, token.fn, this.multiplicative());
    }
    return left;
  }

binaryFn: function(left, fn, right) {
    return extend(function(self, locals) {
      return fn(self, locals, left, right);
    }, {
      constant:left.constant && right.constant
    });
  }

function(){ return number;}

function(self, locals, a,b){
      a=a(self, locals); b=b(self, locals);
      if (isDefined(a)) {
        if (isDefined(b)) {
          return a + b;
        }
        return a;
      }
      return isDefined(b)?b:undefined;}

return (statements.length === 1)
            ? statements[0]
            : function(self, locals) {
                var value;
                for (var i = 0; i < statements.length; i++) {
                  var statement = statements[i];
                  if (statement) {
                    value = statement(self, locals);
                  }
                }
                return value;
              }

$scope.name = '2';
$scope.$eval('1+name'); // ==> 会输出12

return $parse(expr)(this, locals);

 if (!$rootScope.$$phase && !$rootScope.$$asyncQueue.length) {
          $browser.defer(function() {
            if ($rootScope.$$asyncQueue.length) {
              $rootScope.$digest();
            }
          });
        }

this.$$asyncQueue.push({scope: this, expression: expr});

self.defer = function(fn, delay) {
    var timeoutId;
    outstandingRequestCount++;
    timeoutId = setTimeout(function() {
      delete pendingDeferIds[timeoutId];
      completeOutstandingRequest(fn);
    }, delay || 0);
    pendingDeferIds[timeoutId] = true;
    return timeoutId;
  };

this.$$postDigestQueue.push(fn);

$digest: function() {
        var watch, value, last,
            watchers,
            asyncQueue = this.$$asyncQueue,
            postDigestQueue = this.$$postDigestQueue,
            length,
            dirty, ttl = TTL,
            next, current, target = this,
            watchLog = [],
            logIdx, logMsg, asyncTask;

        beginPhase('$digest');

        lastDirtyWatch = null;

        do { // "while dirty" loop
          dirty = false;
          current = target;

          while(asyncQueue.length) {
            try {
              asyncTask = asyncQueue.shift();
              asyncTask.scope.$eval(asyncTask.expression);
            } catch (e) {
              clearPhase();
              $exceptionHandler(e);
            }
            lastDirtyWatch = null;
          }

          traverseScopesLoop:
          do { // "traverse the scopes" loop
            if ((watchers = current.$$watchers)) {
              // process our watches
              length = watchers.length;
              while (length--) {
                try {
                  watch = watchers[length];
                  // Most common watches are on primitives, in which case we can short
                  // circuit it with === operator, only when === fails do we use .equals
                  if (watch) {
                    if ((value = watch.get(current)) !== (last = watch.last) &&
                        !(watch.eq
                            ? equals(value, last)
                            : (typeof value == 'number' && typeof last == 'number'
                               && isNaN(value) && isNaN(last)))) {
                      dirty = true;
                      lastDirtyWatch = watch;
                      watch.last = watch.eq ? copy(value) : value;
                      watch.fn(value, ((last === initWatchVal) ? value : last), current);
                      if (ttl < 5) {
                        logIdx = 4 - ttl;
                        if (!watchLog[logIdx]) watchLog[logIdx] = [];
                        logMsg = (isFunction(watch.exp))
                            ? 'fn: ' + (watch.exp.name || watch.exp.toString())
                            : watch.exp;
                        logMsg += '; newVal: ' + toJson(value) + '; oldVal: ' + toJson(last);
                        watchLog[logIdx].push(logMsg);
                      }
                    } else if (watch === lastDirtyWatch) {
                      // If the most recently dirty watcher is now clean, short circuit since the remaining watchers
                      // have already been tested.
                      dirty = false;
                      break traverseScopesLoop;
                    }
                  }
                } catch (e) {
                  clearPhase();
                  $exceptionHandler(e);
                }
              }
            }

            // Insanity Warning: scope depth-first traversal
            // yes, this code is a bit crazy, but it works and we have tests to prove it!
            // this piece should be kept in sync with the traversal in $broadcast
            if (!(next = (current.$$childHead ||
                (current !== target && current.$$nextSibling)))) {
              while(current !== target && !(next = current.$$nextSibling)) {
                current = current.$parent;
              }
            }
          } while ((current = next));

          // `break traverseScopesLoop;` takes us to here

          if((dirty || asyncQueue.length) && !(ttl--)) {
            clearPhase();
            throw $rootScopeMinErr('infdig',
                '{0} $digest() iterations reached. Aborting!\n' +
                'Watchers fired in the last 5 iterations: {1}',
                TTL, toJson(watchLog));
          }

        } while (dirty || asyncQueue.length);

        clearPhase();

        while(postDigestQueue.length) {
          try {
            postDigestQueue.shift()();
          } catch (e) {
            $exceptionHandler(e);
          }
        }
      }

!(watch.eq
    ? equals(value, last)
    : (typeof value == 'number' && typeof last == 'number'
       && isNaN(value) && isNaN(last)))

if((dirty || asyncQueue.length) && !(ttl--)) {
    clearPhase();
    throw $rootScopeMinErr('infdig',
        '{0} $digest() iterations reached. Aborting!\n' +
        'Watchers fired in the last 5 iterations: {1}',
        TTL, toJson(watchLog));
}

if (ttl < 5) {
    logIdx = 4 - ttl;
    if (!watchLog[logIdx]) watchLog[logIdx] = [];
    logMsg = (isFunction(watch.exp))
        ? 'fn: ' + (watch.exp.name || watch.exp.toString())
        : watch.exp;
    logMsg += '; newVal: ' + toJson(value) + '; oldVal: ' + toJson(last);
    watchLog[logIdx].push(logMsg);
}

// Insanity Warning: scope depth-first traversal
// yes, this code is a bit crazy, but it works and we have tests to prove it!
// this piece should be kept in sync with the traversal in $broadcast
if (!(next = (current.$$childHead ||
      (current !== target && current.$$nextSibling)))) {
    while(current !== target && !(next = current.$$nextSibling)) {
      current = current.$parent;
    }
}

while ((current = next))

else if (watch === lastDirtyWatch) {
    // If the most recently dirty watcher is now clean, short circuit since the remaining watchers
    // have already been tested.
    dirty = false;
    break traverseScopesLoop;
}

while(postDigestQueue.length) {
    try {
      postDigestQueue.shift()();
    } catch (e) {
      $exceptionHandler(e);
    }
}

$apply: function(expr) {
    try {
      beginPhase('$apply');
      return this.$eval(expr);
    } catch (e) {
      $exceptionHandler(e);
    } finally {
      clearPhase();
      try {
        $rootScope.$digest();
      } catch (e) {
        $exceptionHandler(e);
        throw e;
      }
    }
}

$on: function(name, listener) {
        var namedListeners = this.$$listeners[name];
        if (!namedListeners) {
          this.$$listeners[name] = namedListeners = [];
        }
        namedListeners.push(listener);

        var current = this;
        do {
          if (!current.$$listenerCount[name]) {
            current.$$listenerCount[name] = 0;
          }
          current.$$listenerCount[name]++;
        } while ((current = current.$parent));

        var self = this;
        return function() {
          namedListeners[indexOf(namedListeners, listener)] = null;
          decrementListenerCount(self, 1, name);
        };
      }

$emit: function(name, args) {
        var empty = [],
            namedListeners,
            scope = this,
            stopPropagation = false,
            event = {
              name: name,
              targetScope: scope,
              stopPropagation: function() {stopPropagation = true;},
              preventDefault: function() {
                event.defaultPrevented = true;
              },
              defaultPrevented: false
            },
            listenerArgs = concat([event], arguments, 1),
            i, length;

        do {
          namedListeners = scope.$$listeners[name] || empty;
          event.currentScope = scope;
          for (i=0, length=namedListeners.length; i<length; i++) {

            // if listeners were deregistered, defragment the array
            if (!namedListeners[i]) {
              namedListeners.splice(i, 1);
              i--;
              length--;
              continue;
            }
            try {
              //allow all listeners attached to the current scope to run
              namedListeners[i].apply(null, listenerArgs);
            } catch (e) {
              $exceptionHandler(e);
            }
          }
          //if any listener on the current scope stops propagation, prevent bubbling
          if (stopPropagation) return event;
          //traverse upwards
          scope = scope.$parent;
        } while (scope);

        return event;
      }

$broadcast: function(name, args) {
    var target = this,
        current = target,
        next = target,
        event = {
          name: name,
          targetScope: target,
          preventDefault: function() {
            event.defaultPrevented = true;
          },
          defaultPrevented: false
        },
        listenerArgs = concat([event], arguments, 1),
        listeners, i, length;

    //down while you can, then up and next sibling or up and next sibling until back at root
    while ((current = next)) {
      event.currentScope = current;
      listeners = current.$$listeners[name] || [];
      for (i=0, length = listeners.length; i<length; i++) {
        // if listeners were deregistered, defragment the array
        if (!listeners[i]) {
          listeners.splice(i, 1);
          i--;
          length--;
          continue;
        }

        try {
          listeners[i].apply(null, listenerArgs);
        } catch(e) {
          $exceptionHandler(e);
        }
      }

      // Insanity Warning: scope depth-first traversal
      // yes, this code is a bit crazy, but it works and we have tests to prove it!
      // this piece should be kept in sync with the traversal in $digest
      // (though it differs due to having the extra check for $$listenerCount)
      if (!(next = ((current.$$listenerCount[name] && current.$$childHead) ||
          (current !== target && current.$$nextSibling)))) {
        while(current !== target && !(next = current.$$nextSibling)) {
          current = current.$parent;
        }
      }
    }

    return event;
}

$destroy: function() {
    // we can't destroy the root scope or a scope that has been already destroyed
    if (this.$$destroyed) return;
    var parent = this.$parent;

    this.$broadcast('$destroy');
    this.$$destroyed = true;
    if (this === $rootScope) return;

    forEach(this.$$listenerCount, bind(null, decrementListenerCount, this));

    // sever all the references to parent scopes (after this cleanup, the current scope should
    // not be retained by any of our references and should be eligible for garbage collection)
    if (parent.$$childHead == this) parent.$$childHead = this.$$nextSibling;
    if (parent.$$childTail == this) parent.$$childTail = this.$$prevSibling;
    if (this.$$prevSibling) this.$$prevSibling.$$nextSibling = this.$$nextSibling;
    if (this.$$nextSibling) this.$$nextSibling.$$prevSibling = this.$$prevSibling;


    // All of the code below is bogus code that works around V8's memory leak via optimized code
    // and inline caches.
    //
    // see:
    // - https://code.google.com/p/v8/issues/detail?id=2073#c26
    // - https://github.com/angular/angular.js/issues/6794#issuecomment-38648909
    // - https://github.com/angular/angular.js/issues/1313#issuecomment-10378451

    this.$parent = this.$$nextSibling = this.$$prevSibling = this.$$childHead =
        this.$$childTail = this.$root = null;

    // don't reset these to null in case some async task tries to register a listener/watch/task
    this.$$listeners = {};
    this.$$watchers = this.$$asyncQueue = this.$$postDigestQueue = [];

    // prevent NPEs since these methods have references to properties we nulled out
    this.$destroy = this.$digest = this.$apply = noop;
    this.$on = this.$watch = function() { return noop; };
}