require-dust.js

/**
 * AMD implementation for dust.js
 * This is based on require-cs code.
 * see: http://github.com/jrburke/require-cs for details
 */

/*jslint */
/*global define, window, XMLHttpRequest, importScripts, Packages, java,
  ActiveXObject, process, require */

define(['dust'], function(dust) {
    'use strict';
    var fs, getXhr,
        progIds = ['Msxml2.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.4.0'],
        fetchText = function () {
            throw new Error('Environment unsupported.');
        },
        buildMap = {};
    
    dust || (dust = exports);

    if (typeof process !== "undefined" &&
               process.versions &&
               !!process.versions.node) {
        //Using special require.nodeRequire, something added by r.js.
        fs = require.nodeRequire('fs');
        fetchText = function (path, callback) {
            callback(fs.readFileSync(path, 'utf8'));
        };
    } else if ((typeof window !== "undefined" && window.navigator && window.document) || typeof importScripts !== "undefined") {
        // Browser action
        getXhr = function () {
            //Would love to dump the ActiveX crap in here. Need IE 6 to die first.
            var xhr, i, progId;
            if (typeof XMLHttpRequest !== "undefined") {
                return new XMLHttpRequest();
            } else {
                for (i = 0; i < 3; i++) {
                    progId = progIds[i];
                    try {
                        xhr = new ActiveXObject(progId);
                    } catch (e) {}

                    if (xhr) {
                        progIds = [progId];  // so faster next time
                        break;
                    }
                }
            }

            if (!xhr) {
                throw new Error("getXhr(): XMLHttpRequest not available");
            }

            return xhr;
        };

        fetchText = function (url, callback) {
            var xhr = getXhr();
            xhr.open('GET', url, true);
            xhr.onreadystatechange = function (evt) {
                //Do not explicitly handle errors, those should be
                //visible via console output in the browser.
                if (xhr.readyState === 4) {
                    callback(xhr.responseText);
                }
            };
            xhr.send(null);
        };
        // end browser.js adapters
    } else if (typeof Packages !== 'undefined') {
        //Why Java, why is this so awkward?
        fetchText = function (path, callback) {
            var encoding = "utf-8",
                file = new java.io.File(path),
                lineSeparator = java.lang.System.getProperty("line.separator"),
                input = new java.io.BufferedReader(new java.io.InputStreamReader(new java.io.FileInputStream(file), encoding)),
                stringBuffer, line,
                content = '';
            try {
                stringBuffer = new java.lang.StringBuffer();
                line = input.readLine();

                // Byte Order Mark (BOM) - The Unicode Standard, version 3.0, page 324
                // http://www.unicode.org/faq/utf_bom.html

                // Note that when we use utf-8, the BOM should appear as "EF BB BF", but it doesn't due to this bug in the JDK:
                // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4508058
                if (line && line.length() && line.charAt(0) === 0xfeff) {
                    // Eat the BOM, since we've already found the encoding on this file,
                    // and we plan to concatenating this buffer with others; the BOM should
                    // only appear at the top of a file.
                    line = line.substring(1);
                }

                stringBuffer.append(line);

                while ((line = input.readLine()) !== null) {
                    stringBuffer.append(lineSeparator);
                    stringBuffer.append(line);
                }
                //Make sure we return a JavaScript string and not a Java string.
                content = String(stringBuffer.toString()); //String
            } finally {
                input.close();
            }
            callback(content);
        };
    }

    return {
        write: function (pluginName, name, write) {
            if (buildMap.hasOwnProperty(name)) {
                var text = buildMap[name];
                write.asModule(pluginName + "!" + name, text);
            }
        },

        load: function (name, parentRequire, load, config) {
            var path = parentRequire.toUrl(name + '.dust');
            fetchText(path, function (text) {
                //Do dust transform.
                try {
                  text = "define(['dust'],function(dust){"+dust.compile(text, name)+" return {render: function(context, callback) {return dust.render('"+name+"', context, callback)}}})";
                }
                catch (err) {
                  err.message = "In " + path + ", " + err.message;
                  throw(err);
                }

                //Hold on to the transformed text if a build.
                if (config.isBuild) {
                    buildMap[name] = text;
                }

                //IE with conditional comments on cannot handle the
                //sourceURL trick, so skip it if enabled.
                /*@if (@_jscript) @else @*/
                if (!config.isBuild) {
                    text += "\r\n//@ sourceURL=" + path;
                }
                /*@end@*/

                load.fromText('rdust!' + name, text);
            });
        }
    };
});