editor.html now boots with a bit of the plugin system

plugins/pilot/lib/promise.js

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+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (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.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Skywriter.
+ *
+ * The Initial Developer of the Original Code is
+ * Mozilla.
+ * Portions created by the Initial Developer are Copyright (C) 2009
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Joe Walker (jwalker@mozilla.com)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+define(function(require, exports, module) {
+
+var console = require("pilot/console");
+var Trace = require('pilot/stacktrace').Trace;
+
+/**
+ * A promise can be in one of 2 states.
+ * The ERROR and SUCCESS states are terminal, the PENDING state is the only
+ * start state.
+ */
+var ERROR = -1;
+var PENDING = 0;
+var SUCCESS = 1;
+
+/**
+ * We give promises and ID so we can track which are outstanding
+ */
+var _nextId = 0;
+
+/**
+ * Debugging help if 2 things try to complete the same promise.
+ * This can be slow (especially on chrome due to the stack trace unwinding) so
+ * we should leave this turned off in normal use.
+ */
+var _traceCompletion = false;
+
+/**
+ * Outstanding promises. Handy list for debugging only.
+ */
+var _outstanding = [];
+
+/**
+ * Recently resolved promises. Also for debugging only.
+ */
+var _recent = [];
+
+/**
+ * Create an unfulfilled promise
+ */
+Promise = function () {
+    this._status = PENDING;
+    this._value = undefined;
+    this._onSuccessHandlers = [];
+    this._onErrorHandlers = [];
+
+    // Debugging help
+    this._id = _nextId++;
+    //this._createTrace = new Trace(new Error());
+    _outstanding[this._id] = this;
+};
+
+/**
+ * Yeay for RTTI.
+ */
+Promise.prototype.isPromise = true;
+
+/**
+ * Have we either been resolve()ed or reject()ed?
+ */
+Promise.prototype.isComplete = function() {
+    return this._status != PENDING;
+};
+
+/**
+ * Have we resolve()ed?
+ */
+Promise.prototype.isResolved = function() {
+    return this._status == SUCCESS;
+};
+
+/**
+ * Have we reject()ed?
+ */
+Promise.prototype.isRejected = function() {
+    return this._status == ERROR;
+};
+
+/**
+ * Take the specified action of fulfillment of a promise, and (optionally)
+ * a different action on promise rejection.
+ */
+Promise.prototype.then = function(onSuccess, onError) {
+    if (typeof onSuccess === 'function') {
+        if (this._status === SUCCESS) {
+            onSuccess.call(null, this._value);
+        } else if (this._status === PENDING) {
+            this._onSuccessHandlers.push(onSuccess);
+        }
+    }
+
+    if (typeof onError === 'function') {
+        if (this._status === ERROR) {
+            onError.call(null, this._value);
+        } else if (this._status === PENDING) {
+            this._onErrorHandlers.push(onError);
+        }
+    }
+
+    return this;
+};
+
+/**
+ * Like then() except that rather than returning <tt>this</tt> we return
+ * a promise which
+ */
+Promise.prototype.chainPromise = function(onSuccess) {
+    var chain = new Promise();
+    chain._chainedFrom = this;
+    this.then(function(data) {
+        try {
+            chain.resolve(onSuccess(data));
+        } catch (ex) {
+            chain.reject(ex);
+        }
+    }, function(ex) {
+        chain.reject(ex);
+    });
+    return chain;
+};
+
+/**
+ * Supply the fulfillment of a promise
+ */
+Promise.prototype.resolve = function(data) {
+    return this._complete(this._onSuccessHandlers, SUCCESS, data, 'resolve');
+};
+
+/**
+ * Renege on a promise
+ */
+Promise.prototype.reject = function(data) {
+    return this._complete(this._onErrorHandlers, ERROR, data, 'reject');
+};
+
+/**
+ * Internal method to be called on resolve() or reject().
+ * @private
+ */
+Promise.prototype._complete = function(list, status, data, name) {
+    // Complain if we've already been completed
+    if (this._status != PENDING) {
+        console.group('Promise already closed');
+        console.error('Attempted ' + name + '() with ', data);
+        console.error('Previous status = ', this._status,
+                ', previous value = ', this._value);
+        console.trace();
+
+        if (this._completeTrace) {
+            console.error('Trace of previous completion:');
+            this._completeTrace.log(5);
+        }
+        console.groupEnd();
+        return this;
+    }
+
+    if (_traceCompletion) {
+        this._completeTrace = new Trace(new Error());
+    }
+
+    this._status = status;
+    this._value = data;
+
+    // Call all the handlers, and then delete them
+    list.forEach(function(handler) {
+        handler.call(null, this._value);
+    }, this);
+    this._onSuccessHandlers.length = 0;
+    this._onErrorHandlers.length = 0;
+
+    // Remove the given {promise} from the _outstanding list, and add it to the
+    // _recent list, pruning more than 20 recent promises from that list.
+    delete _outstanding[this._id];
+    _recent.push(this);
+    while (_recent.length > 20) {
+        _recent.shift();
+    }
+
+    return this;
+};
+
+/**
+ * Takes an array of promises and returns a promise that that is fulfilled once
+ * all the promises in the array are fulfilled
+ * @param group The array of promises
+ * @return the promise that is fulfilled when all the array is fulfilled
+ */
+Promise.group = function(promiseList) {
+    if (!(promiseList instanceof Array)) {
+        promiseList = Array.prototype.slice.call(arguments);
+    }
+
+    // If the original array has nothing in it, return now to avoid waiting
+    if (promiseList.length === 0) {
+        return new Promise().resolve([]);
+    }
+
+    var groupPromise = new Promise();
+    var results = [];
+    var fulfilled = 0;
+
+    var onSuccessFactory = function(index) {
+        return function(data) {
+            results[index] = data;
+            fulfilled++;
+            // If the group has already failed, silently drop extra results
+            if (groupPromise._status !== ERROR) {
+                if (fulfilled === promiseList.length) {
+                    groupPromise.resolve(results);
+                }
+            }
+        };
+    };
+
+    promiseList.forEach(function(promise, index) {
+        var onSuccess = onSuccessFactory(index);
+        var onError = groupPromise.reject.bind(groupPromise);
+        promise.then(onSuccess, onError);
+    });
+
+    return groupPromise;
+};
+
+exports.Promise = Promise;
+exports._outstanding = _outstanding;
+exports._recent = _recent;
+
+});