From cc5d38293042cb2a37e4c61d4f20f2095951180e Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Mon, 21 Nov 2022 09:56:16 -0800
Subject: [PATCH] client: monitor yield "complete" updates

Populate unchanged fields with most recently received value.
---
 src/clientmon.cpp | 35 +++++++++++++++++++++++++++++++++++
 test/testmon.cpp  | 33 ++++++++++++++++++++++++++++++++-
 2 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/clientmon.cpp b/src/clientmon.cpp
index eb76be6..ca20f05 100644
--- a/src/clientmon.cpp
+++ b/src/clientmon.cpp
@@ -549,6 +549,41 @@ void Connection::handle_MONITOR()
             }
             from_wire_valid(M, rxRegistry, data);
 
+            /* co-iterate data and prototype.
+             * copy   marked from data -> prototype
+             * copy unmarked from prototype -> data
+             */
+            {
+                auto delta = Value::Helper::store_ptr(data);
+                auto complete = Value::Helper::store_ptr(info->prototype);
+                auto N = Value::Helper::desc(info->prototype)->size();
+                for(size_t i=0u; i < N; i++, delta++, complete++)
+                {
+                    const auto src = delta->valid ? delta : complete;
+                    auto       dst = delta->valid ? complete : delta;
+
+                    switch(delta->code) {
+                    case StoreType::Null:
+                        break;
+                    case StoreType::Bool:
+                    case StoreType::UInteger:
+                    case StoreType::Integer:
+                    case StoreType::Real:
+                        memcpy(&dst->store, &src->store, sizeof(src->store));
+                        break;
+                    case StoreType::String:
+                        dst->as<std::string>() = src->as<std::string>();
+                        break;
+                    case StoreType::Array:
+                        dst->as<shared_array<const void>>() = src->as<shared_array<const void>>();
+                        break;
+                    case StoreType::Compound:
+                        dst->as<Value>().copyIn(&src->store, StoreType::Compound);
+                        break;
+                    }
+                }
+            }
+
             BitMask overrun;
             from_wire(M, overrun);
             for(auto i : range(overrun.wsize())) {
diff --git a/test/testmon.cpp b/test/testmon.cpp
index b0581a9..5225988 100644
--- a/test/testmon.cpp
+++ b/test/testmon.cpp
@@ -262,6 +262,36 @@ struct TestLifeCycle : public BasicTest
             testFail("Missing data update");
         }
     }
+
+    void testDelta()
+    {
+        testShow()<<__func__;
+
+        if(auto val = pop(sub, evt)) {
+            testEq(val["value"].as<int32_t>(), 42);
+            testEq(val["alarm.severity"].as<uint32_t>(), 0u);
+            testTrue(val["value"].isMarked(false));
+            testFalse(val["alarm.severity"].isMarked(false));
+        } else {
+            testFail("Missing data update");
+        }
+
+        // leave .value at 42
+        {
+            auto update(initial.cloneEmpty());
+            update["alarm.severity"] = 1;
+            mbox.post(update);
+        }
+
+        if(auto val = pop(sub, evt)) {
+            testEq(val["value"].as<int32_t>(), 42);
+            testEq(val["alarm.severity"].as<uint32_t>(), 1u);
+            testFalse(val["value"].isMarked(false));
+            testTrue(val["alarm.severity"].isMarked(false));
+        } else {
+            testFail("Missing data update");
+        }
+    }
 };
 
 struct TestReconn : public BasicTest
@@ -332,7 +362,7 @@ struct TestReconn : public BasicTest
 
 MAIN(testmon)
 {
-    testPlan(32);
+    testPlan(41);
     testSetup();
     logger_config_env();
     BasicTest().orphan();
@@ -342,6 +372,7 @@ MAIN(testmon)
     TestLifeCycle().testBasic(true);
     TestLifeCycle().testBasic(false);
     TestLifeCycle().testSecond();
+    TestLifeCycle().testDelta();
     TestReconn().testReconn(false);
     TestReconn().testReconn(true);
     cleanup_for_valgrind();