如何在(javascript）Firefox插件中有效地存储传入数据

请求某个URL时，我想保存传入的markdown，将其转换为HTML，然后将其传递给显示。如果使用观察器，我可以获取通道，并通过 nsiTraceableChannel 将通道的侦听器设置为我的特殊"覆盖"侦听器，然后将数据传递给原始侦听器进行显示，但我很困惑此时该怎么做。onDataAvailable 方法传递一个 nsiInputStream，该流无法在 JavaScript 代码中读取。虽然我可以将其包装在 nsiScriptableInputStream 中并从中读取，但这似乎会引入大量围绕可能重复多次的简单读取操作的包装。我宁愿一次用漂亮的封闭二进制代码阅读它。

我想做的是使用 NetUtils.asyncCopy 将该输入流复制到存储流，并在完成后将存储流的结果转换为传递原始侦听器的内容。但是，这不会也继续使用 onDataAvailable 调用我的覆盖侦听器吗？文档说onDataAvalilable必须在返回之前从inputStream中准确读取那么多字节，所以我想使用nsiScriptableInputStream是强制性的吗？我是否只是从可编写脚本的输入流中读取，然后忽略并丢弃它，而异步副本在后台继续？asyncCopy 是用自己的侦听器替换我的覆盖侦听器，这很好，还是它们堆叠，这会很糟糕？

理想情况下，我想要一个接受输出流的东西，并返回一个流侦听器以传递给 nsiTraceableChannel.setInputStream，但我找不到类似的东西，甚至找不到实现 nsiStreamListener 的列表。

所以，像这样：

var {classes: Cc, interfaces: Ci, results: Cr, Constructor: CC, utils: Cu } = Components;
var hack = 3;
/* 
   0 = use nsiScriptableInputStream
   1 = use NetUtil.asyncCopy, and then use nsiScriptableInputStream but ignore
   2 = use NetUtil.asyncCopy, and it overrides our own override listener from then on
   3 = use NetUtil.asyncCopy, but our own override listener keeps getting onDataAvailable, but we just ignore it
*/
var ScriptableInputStream;
if(hack == 0 || hack == 1)  {
    ScriptableInputStream =  CC("@mozilla.org/scriptableinputstream;1","nsIScriptableInputStream", "init");
}
var StorageStream;
var NetUtil;
if(hack != 0) {
    StorageStream = Cc["@mozilla.org/storagestream;1"];
    Cu.import("resource://gre/modules/NetUtil.jsm");
}
function HTMLRestyler(tracingChannel) {
    this.originalListener = tracingChannel.setNewListener(this);
    if(hack == 0) {
        this.data = "";
    } else {
        /* I wonder if creating one of these is as expensive as creating a
           nsiScriptableInputStream for every read operation? */
        this.storage = StorageStream.createInstance(Ci.nsIStorageStream);
        this.storage.init(256,256,null);
        this.data = this.storage.getOutputStream(0);
    }
}
HTMLRestyler.prototype = {
    QueryInterface: function(id)
    {
            if (id.equals(Components.interfaces.nsIStreamListener) ||
                id.equals(Components.interfaces.nsISupportsWeakReference) ||
                id.equals(Components.interfaces.nsISupports))
                return this;
        throw Components.results.NS_NOINTERFACE;
    }
    onDataAvailable: function(request, context, inputStream, offset, count)
    {
        if(hack == 0) {
            var scriptStream = new ScriptableInputStream(inputStream);
            this.data += scriptStream.read(count);
            scriptStream.close();
            /* the easy way (ow my CPU cycles) */
        } else if(hack == 1) {
            if(!this.iscopying) {
                NetUtils.asyncCopy(inputStream,this.data,this.finished);
                this.iscopying = true;
            }
            /* still have to read the data twice once in asyncCopy, once here
               is there any point to doing this? */
            var scriptStream = new ScriptableInputStream(inputStream);
            var ignored = scriptStream.read(count);
            scriptStream.close();
        } else if(hack == 2) {
            NetUtils.asyncCopy(inputStream,this.data,this.finished);
            /* the "best" way
               (probably doesn't work)
               onDataAvailable and onStopRequest no longer called from here on, 
               as this listener has been overridden */
        } else if(hack == 3) {
            if(!this.iscopying) {
                NetUtils.asyncCopy(inputStream,this.data,this.finished);
                this.iscopying = true;
            }
            /* but no scriptable input stream needed because it's ok to just ignore 
               the inputStream here in the override listener and not read data*/
        }
    }
    onStartRequest: function(request, context) {
        this.request = request;
        this.context = context;
    },
    onStopRequest: function(request, context, statusCode) {
        if(hack != 2) {
            this.finished(statusCode);
        }
    },
    finished: function(status) {
        this.originalListener.onStartRequest(this.request,this.context);
        if(hack != 0) {
            var scriptStream = new ScriptableInputStream(this.storage.newInputStream(1));
            this.data = scriptStream.read(1000);
            this.storage.close();
        }
        this.originalListener.onDataAvailable(this.transform(this.data));
        this.originalListener.onStopRequest(this.request, this.context, status);
    },
    transform: function(data) {
        return "derp "+ data;
    }
}