Bug 632227 - NetUtil should have a helper method to read an input stream asynchronously

r=bz
sr=biesi

netwerk/base/src/NetUtil.jsm

@@ -130,21 +130,22 @@ const NetUtil = {
 
     /**
      * Asynchronously opens a source and fetches the response.  A source can be
-     * an nsIURI, nsIFile, string spec, or nsIChannel.  The provided callback
-     * will get an input stream containing the response, the result code, and a
-     * reference to the request.
+     * an nsIURI, nsIFile, string spec, nsIChannel, or nsIInputStream.  The
+     * provided callback will get an input stream containing the response, the
+     * result code, and a reference to the request.
      *
      * @param aSource
-     *        The nsIURI, nsIFile, string spec, or nsIChannel to open.
+     *        The nsIURI, nsIFile, string spec, nsIChannel, or nsIInputStream
+     *        to open.
      *        Note: If passing an nsIChannel whose notificationCallbacks is
      *              already set, callers are responsible for implementations
      *              of nsIBadCertListener/nsISSLErrorListener.
      * @param aCallback
      *        The callback function that will be notified upon completion.  It
      *        will get two arguments:
-     *        1) An nsIInputStream containing the data from the channel, if any.
+     *        1) An nsIInputStream containing the data from aSource, if any.
      *        2) The status code from opening the source.
-     *        3) Reference to the channel (as an nsIRequest).
+     *        3) Reference to the nsIRequest.
      */
     asyncFetch: function NetUtil_asyncOpen(aSource, aCallback)
     {
@@ -174,6 +175,15 @@ const NetUtil = {
             }
         });
 
+        // Input streams are handled slightly differently from everything else.
+        if (aSource instanceof Ci.nsIInputStream) {
+            let pump = Cc["@mozilla.org/network/input-stream-pump;1"].
+                       createInstance(Ci.nsIInputStreamPump);
+            pump.init(aSource, -1, -1, 0, 0, true);
+            pump.asyncRead(listener, null);
+            return;
+        }
+
         let channel = aSource;
         if (!(channel instanceof Ci.nsIChannel)) {
             channel = this.newChannel(aSource);

netwerk/test/unit/test_NetUtil.js

@@ -16,7 +16,7 @@
  * The Original Code is Necko Test Code.
  *
  * The Initial Developer of the Original Code is
- * Mozilla Corporation.
+ * the Mozilla Foundation.
  * Portions created by the Initial Developer are Copyright (C) 2009
  * the Initial Developer. All Rights Reserved.
  *
@@ -352,6 +352,27 @@ function test_asyncFetch_with_nsIFile()
   });
 }
 
+function test_asyncFetch_with_nsIInputString()
+{
+  const TEST_DATA = "this is a test string";
+  let istream = Cc["@mozilla.org/io/string-input-stream;1"].
+                createInstance(Ci.nsIStringInputStream);
+  istream.setData(TEST_DATA, TEST_DATA.length);
+
+  // Read the input stream asynchronously.
+  NetUtil.asyncFetch(istream, function(aInputStream, aResult) {
+    // Check that we had success.
+    do_check_true(Components.isSuccessCode(aResult));
+
+    // Check that we got the right data.
+    do_check_eq(aInputStream.available(), TEST_DATA.length);
+    do_check_eq(NetUtil.readInputStreamToString(aInputStream, TEST_DATA.length),
+                TEST_DATA);
+
+    run_next_test();
+  });
+}
+
 function test_asyncFetch_does_not_block()
 {
   // Create our channel that has no data.
@@ -533,6 +554,7 @@ let tests = [
   test_asyncFetch_with_nsIURI,
   test_asyncFetch_with_string,
   test_asyncFetch_with_nsIFile,
+  test_asyncFetch_with_nsIInputString,
   test_asyncFetch_does_not_block,
   test_newChannel_no_specifier,
   test_newChannel_with_string,