Add memoryUsage() to ElementProxy and MemberProxy (fixes #1730)

CHANGELOG.md

@@ -1,6 +1,12 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Add `ElementProxy::memoryUsage()`
+* Add `MemberProxy::memoryUsage()` (issue #1730)
+
 v6.19.3 (2022-03-08)
 -------
 

extras/tests/JsonDocument/DynamicJsonDocument.cpp

@@ -205,4 +205,26 @@ TEST_CASE("DynamicJsonDocument assignment") {
     REQUIRE_JSON(doc2, "42");
     REQUIRE(doc2.capacity() == 4096);
   }
+
+  SECTION("Assign from MemberProxy") {
+    StaticJsonDocument<200> doc1;
+    doc1["value"] = 42;
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = doc1["value"];
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == 4096);
+  }
+
+  SECTION("Assign from ElementProxy") {
+    StaticJsonDocument<200> doc1;
+    doc1[0] = 42;
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = doc1[0];
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == 4096);
+  }
 }

extras/tests/JsonDocument/ElementProxy.cpp

@@ -188,6 +188,21 @@ TEST_CASE("ElementProxy::size()") {
   }
 }
 
+TEST_CASE("ElementProxy::memoryUsage()") {
+  DynamicJsonDocument doc(4096);
+  doc.addElement();
+  ElementProxy<JsonDocument&> ep = doc[0];
+
+  SECTION("returns 0 for null") {
+    REQUIRE(ep.memoryUsage() == 0);
+  }
+
+  SECTION("returns size for string") {
+    ep.set(std::string("hello"));
+    REQUIRE(ep.memoryUsage() == 6);
+  }
+}
+
 TEST_CASE("ElementProxy::operator[]") {
   DynamicJsonDocument doc(4096);
   ElementProxy<JsonDocument&> ep = doc[1];

extras/tests/JsonDocument/MemberProxy.cpp

@@ -229,6 +229,20 @@ TEST_CASE("MemberProxy::size()") {
   }
 }
 
+TEST_CASE("MemberProxy::memoryUsage()") {
+  DynamicJsonDocument doc(4096);
+  MemberProxy<JsonDocument &, const char *> mp = doc["hello"];
+
+  SECTION("returns 0 when null") {
+    REQUIRE(mp.memoryUsage() == 0);
+  }
+
+  SECTION("return the size for a string") {
+    mp.set(std::string("hello"));
+    REQUIRE(mp.memoryUsage() == 6);
+  }
+}
+
 TEST_CASE("MemberProxy::operator[]") {
   DynamicJsonDocument doc(4096);
   MemberProxy<JsonDocument &, const char *> mp = doc["hello"];

src/ArduinoJson/Array/ElementProxy.hpp

@@ -118,6 +118,10 @@ class ElementProxy : public VariantOperators<ElementProxy<TArray> >,
     return getUpstreamElement().size();
   }
 
+  FORCE_INLINE size_t memoryUsage() const {
+    return getUpstreamElement().memoryUsage();
+  }
+
   template <typename TNestedKey>
   VariantRef getMember(TNestedKey* key) const {
     return getUpstreamElement().getMember(key);

src/ArduinoJson/Object/MemberProxy.hpp

@@ -94,6 +94,10 @@ class MemberProxy : public VariantOperators<MemberProxy<TObject, TStringRef> >,
     return getUpstreamMember().size();
   }
 
+  FORCE_INLINE size_t memoryUsage() const {
+    return getUpstreamMember().memoryUsage();
+  }
+
   FORCE_INLINE void remove(size_t index) const {
     getUpstreamMember().remove(index);
   }