Add option to check stream in object.validate

lib/structs.js

@@ -367,7 +367,7 @@ var object = exports.object = {
     var decodedStream = var_int.decode(decodedVersion.rest);
     var headerLength = 20 + decodedVersion.length + decodedStream.length;
 
-    if (opts._validate) { return; }
+    if (opts._validate) { return {stream: decodedStream.value}; }
 
     var objectPayload = new Buffer(decodedStream.rest.length);
     decodedStream.rest.copy(objectPayload);
@@ -387,7 +387,8 @@ var object = exports.object = {
    * Check whether given `object` message is valid.
    * @param {Buffer} buf - Message
    * @param {Object=} opts - Any of [object.decode]{@link
-   * module:bitmessage/structs.object.decode} options
+   * module:bitmessage/structs.object.decode} options and:
+   * @param {number} opts.stream - Expected object's stream
    * @return {?Error} Return an error with description if object is
    * invalid.
    */
@@ -411,11 +412,18 @@ var object = exports.object = {
    */
   validatePayload: function(buf, opts) {
     opts = objectAssign({}, opts, {_validate: true});
+    var decoded;
     try {
-      object.decodePayload(buf, opts);
+      decoded = object.decodePayload(buf, opts);
     } catch(e) {
       return e;
     }
+    if (opts.stream && decoded.stream !== opts.stream) {
+      return new Error(
+        "The stream number " + opts.stream +
+        " is not the one we are interested in"
+      );
+    }
   },
 
   /**

test.js

@@ -261,7 +261,19 @@ describe("Common structures", function() {
       err = object.validatePayload(obj);
       expect(err.message).to.match(/insufficient pow/i);
 
-      expect(object.validatePayload(obj, {skipPow: true})).to.not.exist;
+      expect(object.validatePayload(obj, skipPow)).to.not.exist;
+    });
+
+    it("should allow to validate stream", function() {
+      var obj = object.encodePayload({
+        nonce: Buffer(8),
+        ttl: 111,
+        type: object.MSG,
+        version: 1,
+        objectPayload: Buffer(0),
+      });
+      var err = object.validatePayload(obj, {skipPow: true, stream: 3});
+      expect(err.message).to.match(/stream.*is not the one/i);
     });
   });