From 49e4aa4158a73417061e811b1c920fdb89558312 Mon Sep 17 00:00:00 2001
From: Kagami Hiiragi <kagami@genshiken.org>
Date: Mon, 16 Feb 2015 19:47:19 +0300
Subject: [PATCH] Add object.validate API

---
 lib/structs.js | 53 +++++++++++++++++++++++++++++++++++++++++++++-----
 tests/unit.js  | 19 +++++++++++++++++-
 2 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/lib/structs.js b/lib/structs.js
index 6ce66bb..5c240ce 100644
--- a/lib/structs.js
+++ b/lib/structs.js
@@ -316,12 +316,13 @@ var object = exports.object = {
    * @param {Object=} opts - Decoding options
    * @param {boolean} opts.allowExpired - Allow expired objects
    * @param {boolean} opts.skipPow - Do not validate object POW
-   * @return {DecodeResult}
-   * [Decoded `object` structure.]{@link module:bitmessage/structs.object.DecodeResult}
+   * @return {DecodeResult} [Decoded `object` structure.]{@link
+   * module:bitmessage/structs.object.DecodeResult}
+   * @throws {Error} Invalid object
    */
   decode: function(buf, opts) {
     var decoded = message.decode(buf);
-    assert(decoded.command === "object", "Bad command");
+    assert(decoded.command === "object", "Given message is not an object");
     return object.decodePayload(decoded.payload, opts);
   },
 
@@ -331,11 +332,15 @@ var object = exports.object = {
    */
   decodePayload: function(buf, opts) {
     opts = opts || {};
+
     // 8 + 8 + 4 + (1+) + (1+)
     assert(buf.length >= 22, "object message payload is too small");
     assert(buf.length <= 262144, "object message payload is too big");
-    var nonce = new Buffer(8);
-    buf.copy(nonce, 0, 0, 8);
+    var nonce;
+    if (!opts._validate) {
+      nonce = new Buffer(8);
+      buf.copy(nonce, 0, 0, 8);
+    }
 
     // TTL.
     var expiresTime = util.readTimestamp64BE(buf.slice(8, 16));
@@ -358,6 +363,9 @@ var object = exports.object = {
     var decodedVersion = var_int.decode(buf.slice(20));
     var decodedStream = var_int.decode(decodedVersion.rest);
     var headerLength = 20 + decodedVersion.length + decodedStream.length;
+
+    if (opts._validate) { return; }
+
     var objectPayload = new Buffer(decodedStream.rest.length);
     decodedStream.rest.copy(objectPayload);
 
@@ -372,6 +380,41 @@ 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
+   * @return {?Error} Return an error with description if object is
+   * invalid.
+   */
+  validate: function(buf, opts) {
+    var decoded;
+    try {
+      decoded = message.decode(buf);
+    } catch(e) {
+      return e;
+    }
+    if (decoded.command !== "object") {
+      return new Error("Given message is not an object");
+    }
+    return object.validatePayload(decoded.payload, opts);
+  },
+
+  /**
+   * Check whether `object` message payload is valid.
+   * The same as [validate]{@link
+   * module:bitmessage/structs.object.validate}.
+   */
+  validatePayload: function(buf, opts) {
+    opts = objectAssign({}, opts, {_validate: true});
+    try {
+      object.decodePayload(buf, opts);
+    } catch(e) {
+      return e;
+    }
+  },
+
   /**
    * Encode `object` message.
    * @param {Object} opts - Object options
diff --git a/tests/unit.js b/tests/unit.js
index 21d0574..ca921b1 100644
--- a/tests/unit.js
+++ b/tests/unit.js
@@ -114,7 +114,6 @@ describe("Crypto", function() {
   });
 });
 
-// TODO(Kagami): Add tests for encodePayload/decodePayload as well.
 describe("Common structures", function() {
   describe("message", function() {
     it("should decode", function() {
@@ -246,6 +245,24 @@ describe("Common structures", function() {
         objectPayload: Buffer("test"),
       }))).to.throw(/insufficient/i);
     });
+
+    it("should allow to validate object", function() {
+      var verackmsg = message.encode("verack");
+      var err = object.validate(verackmsg);
+      expect(err.message).to.match(/not an object/i);
+
+      var obj = object.encodePayload({
+        nonce: Buffer(8),
+        ttl: 111,
+        type: object.MSG,
+        version: 1,
+        objectPayload: Buffer(0),
+      });
+      err = object.validatePayload(obj);
+      expect(err.message).to.match(/insufficient pow/i);
+
+      expect(object.validatePayload(obj, {skipPow: true})).to.not.exist;
+    });
   });
 
   describe("var_int", function() {