More work on diff xmit, not finished yet

luprex/core/cpp/animqueue.cpp

@@ -447,23 +447,22 @@ void AnimQueue::deserialize(StreamBuffer *sb) {
     }
 }
 
-bool AnimQueue::make_patch(const AnimQueue &auth, StreamBuffer *sb) const {
+bool AnimQueue::need_patch(const AnimQueue &auth) const {
     // Sanity check.
     assert(valid());
     assert(auth.valid());
-    
+
     // Fast path to detect equivalence.
     if (version_number_ == auth.version_number_) {
-        sb->write_uint8(0);
         return false;
     }
 
-    // Special case: if we're already a perfect match.
-    if (size_and_steps_equal(auth)) {
-        sb->write_uint8(0);
-        return false;
-    }
-    
+    // Otherwise, do a direct comparison.
+    return !size_and_steps_equal(auth);
+}
+
+
+void AnimQueue::diff(const AnimQueue &auth, StreamBuffer *sb) const {
     // Write the first element.
     sb->write_uint8(auth.steps_.size());
     sb->write_uint8(auth.size_limit_);
@@ -502,14 +501,10 @@ bool AnimQueue::make_patch(const AnimQueue &auth, StreamBuffer *sb) const {
             }
         }
     }
-    return true;
 }
 
-void AnimQueue::apply_patch(StreamBuffer *sb) {
+void AnimQueue::patch(StreamBuffer *sb) {
     int len = sb->read_uint8();
-    if (len == 0) {
-        return;
-    }
     size_limit_ = sb->read_uint8();
     // Decode the diff, stop at eof.
     std::deque<AnimStep> old = std::move(steps_);
@@ -545,8 +540,8 @@ const AnimStep &AnimQueue::back() const {
 
 static bool diff_works(const AnimQueue &master, AnimQueue &sync) {
     StreamBuffer sb;
-    sync.make_patch(master, &sb);
-    sync.apply_patch(&sb);
+    sync.diff(master, &sb);
+    sync.patch(&sb);
     return sync.size_and_steps_equal(master);
 }
 
@@ -647,10 +642,8 @@ LuaDefine(unittests_animqueue, "c") {
     LuaAssert(L, diff_works(aq, aqds));
 
     // compare again, should be no differences.
-    sb.clear();
-    LuaAssert(L, !aqds.make_patch(aq, &sb));
-    aqds.apply_patch(&sb);
-    LuaAssert(L, aqds.size_and_steps_equal(aq));
+    LuaAssert(L, !aqds.need_patch(aq));
+    LuaAssert(L, diff_works(aq, aqds));
 
     // Discard all but the last action.
     aq.set_limit(1);