[tor-commits] [meek/master] Read data before bailing out in onDataAvailable.

[dcf at torproject.org]

commit 1f88a0e204433d28a33e7df66681bd74f27f3b0a
Author: David Fifield <david at bamsoftware.com>
Date:   Sun Feb 22 15:14:07 2015 -0800

    Read data before bailing out in onDataAvailable.
    
    https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/NsIStreamListener#onDataAvailable%28%29
    says "Your implementation of this method must read exactly aCount bytes
    of data before returning."
    
    It's already downloaded, so it doesn't cost much to read it out of the
    buffer. Without this, I got "http channel Listener OnDataAvailable
    contract violation" in the console. (I had to purposely induce an
    overlong download to get it to happen.)
---
 firefox/components/main.js |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/firefox/components/main.js b/firefox/components/main.js
index b851d49..0ec6831 100644
--- a/firefox/components/main.js
+++ b/firefox/components/main.js
@@ -434,15 +434,15 @@ MeekHTTPHelper.HttpStreamListener.prototype = {
     // https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIStreamListener
     onDataAvailable: function(request, context, stream, sourceOffset, length) {
         // dump("onDataAvailable " + length + " bytes\n");
-        if (this.length + length > 1000000) {
-            request.cancel(Components.results.NS_ERROR_ILLEGAL_VALUE);
-            return;
-        }
         this.length += length;
         let input = Components.classes["@mozilla.org/binaryinputstream;1"]
             .createInstance(Components.interfaces.nsIBinaryInputStream);
         input.setInputStream(stream);
         this.body.push(String.fromCharCode.apply(null, input.readByteArray(length)));
+        if (this.length > 1000000) {
+            request.cancel(Components.results.NS_ERROR_ILLEGAL_VALUE);
+            return;
+        }
     },
 };