source: Dev/trunk/src/client/util/build/transforms/writeCss.js

define([
        "../buildControl",
        "../fileUtils",
        "../fs"
], function(bc, fileUtils, fs){
        return function(resource, callback){
                var
                        waitCount = 0,

                        errors = [],

                        onWriteComplete = function(err){
                                if(err){
                                        errors.push(err);
                                }
                                if(--waitCount==0){
                                        callback(resource, errors.length && errors);
                                }
                        },

                        doWrite = function(filename, text, encoding){
                                fileUtils.ensureDirectoryByFilename(filename);
                                waitCount++;
                                fs.writeFile(filename, bc.newlineFilter(text, resource, "writeCss"), encoding || "utf8", onWriteComplete);
                                // this must go *after* the async call
                        },

                        wroteExterns = 0;

                try{
                        doWrite(resource.dest, resource.text);
                        if(resource.compactDest!=resource.dest){
                                doWrite(resource.compactDest, resource.compactText);
                        }

                        // only need to tranverse bc.destDirToExternSet once...
                        if(wroteExterns){
                                return callback;
                        }
                        wroteExterns = 1;
                        // bc.destDirToExternSet is a map from dest directory name to resourceSet;
                        // resourceSet is a map from src filename (complete with path) to dest filename (name only)
                        // bc.destDirToExternSet[dir][src]= dest implies copy filename src to dir + "/" + dest
                        var
                                destDirToExternSet = bc.destDirToExternSet,
                                dir, resourceSet, src;
                        for(dir in destDirToExternSet){
                                resourceSet = destDirToExternSet[dir];
                                for(src in resourceSet){
                                        doWrite(dir + "/" + resourceSet[src], bc.resources[src].text, resource.encoding);
                                }
                        }
                }catch(e){
                        if(waitCount){
                                // can't return the error since there are async processes already going
                                errors.push(e);
                                return 0;
                        }else{
                                return e;
                        }
                }
                return callback;
        };
});