Add JsonVariant::link()

extras/tests/JsonDocument/ElementProxy.cpp

@@ -245,3 +245,11 @@ TEST_CASE("ElementProxy cast to JsonVariant") {
 
   CHECK(doc.as<std::string>() == "[\"toto\"]");
 }
+
+TEST_CASE("ElementProxy::link()") {
+  StaticJsonDocument<1024> doc1, doc2;
+  doc1[0].link(doc2);
+  doc2["hello"] = "world";
+
+  CHECK(doc1.as<std::string>() == "[{\"hello\":\"world\"}]");
+}

extras/tests/JsonDocument/MemberProxy.cpp

@@ -285,3 +285,43 @@ TEST_CASE("MemberProxy cast to JsonVariant") {
 
   CHECK(doc.as<std::string>() == "{\"hello\":\"toto\"}");
 }
+
+TEST_CASE("MemberProxy::createNestedArray()") {
+  StaticJsonDocument<1024> doc;
+  JsonArray arr = doc["items"].createNestedArray();
+  arr.add(42);
+
+  CHECK(doc["items"][0][0] == 42);
+}
+
+TEST_CASE("MemberProxy::createNestedArray(key)") {
+  StaticJsonDocument<1024> doc;
+  JsonArray arr = doc["weather"].createNestedArray("temp");
+  arr.add(42);
+
+  CHECK(doc["weather"]["temp"][0] == 42);
+}
+
+TEST_CASE("MemberProxy::createNestedObject()") {
+  StaticJsonDocument<1024> doc;
+  JsonObject obj = doc["items"].createNestedObject();
+  obj["value"] = 42;
+
+  CHECK(doc["items"][0]["value"] == 42);
+}
+
+TEST_CASE("MemberProxy::createNestedObject(key)") {
+  StaticJsonDocument<1024> doc;
+  JsonObject obj = doc["status"].createNestedObject("weather");
+  obj["temp"] = 42;
+
+  CHECK(doc["status"]["weather"]["temp"] == 42);
+}
+
+TEST_CASE("MemberProxy::link()") {
+  StaticJsonDocument<1024> doc1, doc2;
+  doc1["obj"].link(doc2);
+  doc2["hello"] = "world";
+
+  CHECK(doc1.as<std::string>() == "{\"obj\":{\"hello\":\"world\"}}");
+}

extras/tests/JsonVariant/CMakeLists.txt

@@ -8,11 +8,12 @@ add_executable(JsonVariantTests
 	clear.cpp
 	compare.cpp
 	containsKey.cpp
-	copy.cpp
 	converters.cpp
+	copy.cpp
 	createNested.cpp
 	is.cpp
 	isnull.cpp
+	link.cpp
 	memoryUsage.cpp
 	misc.cpp
 	nesting.cpp
@@ -20,6 +21,7 @@ add_executable(JsonVariantTests
 	overflow.cpp
 	remove.cpp
 	set.cpp
+	size.cpp
 	subscript.cpp
 	types.cpp
 	unbound.cpp

extras/tests/JsonVariant/add.cpp

@@ -43,4 +43,14 @@ TEST_CASE("JsonVariant::add()") {
 
     REQUIRE(var.as<std::string>() == "{\"val\":123}");
   }
+
+  SECTION("add to linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2.add(42);
+    var.link(doc2);
+
+    var.add(666);  // no-op
+
+    CHECK(var.as<std::string>() == "[42]");
+  }
 }

extras/tests/JsonVariant/as.cpp

@@ -267,4 +267,97 @@ TEST_CASE("JsonVariant::as()") {
 
     REQUIRE(variant.as<MY_ENUM>() == ONE);
   }
+
+  SECTION("linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
+
+    SECTION("as<std::string>()") {
+      CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+    }
+
+    SECTION("as<JsonArray>()") {
+      JsonArray a = variant.as<JsonArray>();
+      CHECK(a.isNull() == true);
+    }
+
+    SECTION("as<JsonObject>()") {
+      JsonObject o = variant.as<JsonObject>();
+      CHECK(o.isNull() == true);
+    }
+
+    SECTION("as<JsonObjectConst>()") {
+      JsonObjectConst o = variant.as<JsonObjectConst>();
+      CHECK(o.isNull() == false);
+      CHECK(o.size() == 1);
+      CHECK(o["hello"] == "world");
+    }
+  }
+
+  SECTION("linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2.add("hello");
+    doc2.add("world");
+    variant.link(doc2);
+
+    SECTION("as<std::string>()") {
+      CHECK(variant.as<std::string>() == "[\"hello\",\"world\"]");
+    }
+
+    SECTION("as<JsonArray>()") {
+      JsonArray a = variant.as<JsonArray>();
+      CHECK(a.isNull() == true);
+    }
+
+    SECTION("as<JsonArrayConst>()") {
+      JsonArrayConst a = variant.as<JsonArrayConst>();
+      CHECK(a.isNull() == false);
+      CHECK(a.size() == 2);
+      CHECK(a[0] == "hello");
+      CHECK(a[1] == "world");
+    }
+
+    SECTION("as<JsonObject>()") {
+      JsonObject o = variant.as<JsonObject>();
+      CHECK(o.isNull() == true);
+    }
+  }
+
+  SECTION("linked int") {
+    StaticJsonDocument<128> doc2;
+    doc2.set(42);
+    variant.link(doc2);
+
+    CHECK(variant.as<int>() == 42);
+    CHECK(variant.as<double>() == 42.0);
+  }
+
+  SECTION("linked double") {
+    StaticJsonDocument<128> doc2;
+    doc2.set(42.0);
+    variant.link(doc2);
+
+    CHECK(variant.as<int>() == 42);
+    CHECK(variant.as<double>() == 42.0);
+  }
+
+  SECTION("linked string") {
+    StaticJsonDocument<128> doc2;
+    doc2.set("hello");
+    variant.link(doc2);
+
+    CHECK(variant.as<std::string>() == "hello");
+  }
+
+  SECTION("linked bool") {
+    StaticJsonDocument<128> doc2;
+    variant.link(doc2);
+
+    doc2.set(true);
+    CHECK(variant.as<bool>() == true);
+
+    doc2.set(false);
+    CHECK(variant.as<bool>() == false);
+  }
 }

extras/tests/JsonVariant/clear.cpp

@@ -23,4 +23,15 @@ TEST_CASE("JsonVariant::clear()") {
 
     REQUIRE(var.isNull() == true);
   }
+
+  SECTION("doesn't alter linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    var.clear();
+
+    CHECK(var.isNull() == true);
+    CHECK(doc2.as<std::string>() == "{\"hello\":\"world\"}");
+  }
 }

extras/tests/JsonVariant/compare.cpp

@@ -34,6 +34,20 @@ TEST_CASE("Compare JsonVariant with value") {
     CHECK_FALSE(a < b);
     CHECK_FALSE(a > b);
   }
+
+  SECTION("linked 42 vs 42") {
+    StaticJsonDocument<128> doc2;
+    doc2.set(42);
+    a.link(doc2);
+    int b = 42;
+
+    CHECK(a == b);
+    CHECK(a <= b);
+    CHECK(a >= b);
+    CHECK_FALSE(a != b);
+    CHECK_FALSE(a < b);
+    CHECK_FALSE(a > b);
+  }
 }
 
 TEST_CASE("Compare JsonVariant with JsonVariant") {
@@ -313,4 +327,19 @@ TEST_CASE("Compare JsonVariant with JsonVariant") {
     CHECK_FALSE(a > b);
     CHECK_FALSE(a >= b);
   }
+
+  SECTION("linked 42 vs link 42") {
+    StaticJsonDocument<128> doc2, doc3;
+    doc2.set(42);
+    doc3.set(42);
+    a.link(doc2);
+    b.link(doc3);
+
+    CHECK(a == b);
+    CHECK(a <= b);
+    CHECK(a >= b);
+    CHECK_FALSE(a != b);
+    CHECK_FALSE(a < b);
+    CHECK_FALSE(a > b);
+  }
 }

extras/tests/JsonVariant/containsKey.cpp

@@ -12,19 +12,28 @@ TEST_CASE("JsonVariant::containsKey()") {
   DynamicJsonDocument doc(4096);
   JsonVariant var = doc.to<JsonVariant>();
 
-  SECTION("containsKey(const char*) returns true") {
+  SECTION("containsKey(const char*)") {
     var["hello"] = "world";
 
     REQUIRE(var.containsKey("hello") == true);
     REQUIRE(var.containsKey("world") == false);
   }
 
-  SECTION("containsKey(std::string) returns true") {
+  SECTION("containsKey(std::string)") {
     var["hello"] = "world";
 
     REQUIRE(var.containsKey(std::string("hello")) == true);
     REQUIRE(var.containsKey(std::string("world")) == false);
   }
+
+  SECTION("linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    CHECK(var.containsKey("hello") == true);
+    CHECK(var.containsKey("world") == false);
+  }
 }
 
 TEST_CASE("JsonVariantConst::containsKey()") {

extras/tests/JsonVariant/copy.cpp

@@ -84,6 +84,16 @@ TEST_CASE("JsonVariant::set(JsonVariant)") {
     REQUIRE(doc2.memoryUsage() == JSON_STRING_SIZE(7));
   }
 
+  SECTION("stores linked object by pointer") {
+    StaticJsonDocument<128> doc3;
+    doc3["hello"] = "world";
+    var1.link(doc3);
+    var2.set(var1);
+
+    REQUIRE(doc1.memoryUsage() == 0);
+    REQUIRE(doc2.memoryUsage() == 0);
+  }
+
   SECTION("destination is unbound") {
     JsonVariant unboundVariant;
 

extras/tests/JsonVariant/createNested.cpp

@@ -19,11 +19,15 @@ TEST_CASE("JsonVariant::createNestedObject()") {
     REQUIRE(obj.isNull() == false);
   }
 
-  SECTION("works on MemberProxy") {
-    JsonObject obj = variant["items"].createNestedObject();
-    obj["value"] = 42;
+  SECTION("does nothing on linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2[0] = 42;
+    variant.link(doc2);
 
-    REQUIRE(variant["items"][0]["value"] == 42);
+    variant.createNestedObject();
+
+    CHECK(variant.size() == 1);
+    CHECK(variant[0] == 42);
   }
 }
 
@@ -38,11 +42,15 @@ TEST_CASE("JsonVariant::createNestedArray()") {
     REQUIRE(arr.isNull() == false);
   }
 
-  SECTION("works on MemberProxy") {
-    JsonArray arr = variant["items"].createNestedArray();
-    arr.add(42);
+  SECTION("does nothing on linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2[0] = 42;
+    variant.link(doc2);
 
-    REQUIRE(variant["items"][0][0] == 42);
+    variant.createNestedArray();
+
+    CHECK(variant.size() == 1);
+    CHECK(variant[0] == 42);
   }
 }
 
@@ -58,11 +66,15 @@ TEST_CASE("JsonVariant::createNestedObject(key)") {
     REQUIRE(variant["weather"]["temp"] == 42);
   }
 
-  SECTION("works on MemberProxy") {
-    JsonObject obj = variant["status"].createNestedObject("weather");
-    obj["temp"] = 42;
+  SECTION("does nothing on linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
 
-    REQUIRE(variant["status"]["weather"]["temp"] == 42);
+    variant.createNestedObject("weather");
+
+    CHECK(variant.size() == 1);
+    CHECK(variant["hello"] == "world");
   }
 }
 
@@ -77,10 +89,14 @@ TEST_CASE("JsonVariant::createNestedArray(key)") {
     REQUIRE(arr.isNull() == false);
   }
 
-  SECTION("works on MemberProxy") {
-    JsonArray arr = variant["weather"].createNestedArray("temp");
-    arr.add(42);
+  SECTION("does nothing on linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
 
-    REQUIRE(variant["weather"]["temp"][0] == 42);
+    variant.createNestedArray("items");
+
+    CHECK(variant.size() == 1);
+    CHECK(variant["hello"] == "world");
   }
 }

extras/tests/JsonVariant/is.cpp

@@ -144,6 +144,24 @@ TEST_CASE("JsonVariant::is<T>()") {
     CHECK(variant.is<MYENUM2>() == false);
   }
 
+  SECTION("linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2[0] = "world";
+    variant.link(doc2);
+
+    CHECK(variant.is<JsonArray>() == false);
+    CHECK(variant.is<JsonArrayConst>() == true);
+    CHECK(variant.is<JsonVariant>() == true);
+    CHECK(variant.is<JsonVariantConst>() == true);
+    CHECK(variant.is<JsonObject>() == false);
+    CHECK(variant.is<JsonObjectConst>() == false);
+    CHECK(variant.is<int>() == false);
+    CHECK(variant.is<float>() == false);
+    CHECK(variant.is<bool>() == false);
+    CHECK(variant.is<const char *>() == false);
+    CHECK(variant.is<MYENUM2>() == false);
+  }
+
   SECTION("JsonObject") {
     variant.to<JsonObject>();
 
@@ -161,6 +179,44 @@ TEST_CASE("JsonVariant::is<T>()") {
     CHECK(variant.is<JsonVariant>() == true);
     CHECK(variant.is<JsonVariantConst>() == true);
   }
+
+  SECTION("linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
+
+    CHECK(variant.is<JsonObject>() == false);
+    CHECK(variant.is<JsonObjectConst>() == true);
+    CHECK(variant.is<JsonVariant>() == true);
+    CHECK(variant.is<JsonVariantConst>() == true);
+    CHECK(variant.is<JsonArray>() == false);
+    CHECK(variant.is<JsonArrayConst>() == false);
+    CHECK(variant.is<int>() == false);
+    CHECK(variant.is<float>() == false);
+    CHECK(variant.is<bool>() == false);
+    CHECK(variant.is<const char *>() == false);
+    CHECK(variant.is<MYENUM2>() == false);
+    CHECK(variant.is<JsonVariant>() == true);
+    CHECK(variant.is<JsonVariantConst>() == true);
+  }
+
+  SECTION("linked int") {
+    StaticJsonDocument<1024> doc2;
+    doc2.set(42);
+    variant.link(doc2);
+
+    CHECK(variant.is<JsonObjectConst>() == false);
+    CHECK(variant.is<JsonVariantConst>() == true);
+    CHECK(variant.is<JsonObject>() == false);
+    CHECK(variant.is<JsonVariant>() == true);
+    CHECK(variant.is<JsonArray>() == false);
+    CHECK(variant.is<JsonArrayConst>() == false);
+    CHECK(variant.is<int>() == true);
+    CHECK(variant.is<float>() == false);
+    CHECK(variant.is<bool>() == false);
+    CHECK(variant.is<const char *>() == false);
+    CHECK(variant.is<MYENUM2>() == true);
+  }
 }
 
 TEST_CASE("JsonVariantConst::is<T>()") {
@@ -316,4 +372,58 @@ TEST_CASE("JsonVariantConst::is<T>()") {
     CHECK(cvariant.is<const char *>() == false);
     CHECK(cvariant.is<MYENUM2>() == false);
   }
+
+  SECTION("linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2[0] = "world";
+    variant.link(doc2);
+
+    CHECK(cvariant.is<JsonArrayConst>() == true);
+    CHECK(cvariant.is<JsonVariantConst>() == true);
+    CHECK(cvariant.is<JsonArray>() == false);
+    CHECK(cvariant.is<JsonVariant>() == false);
+    CHECK(cvariant.is<JsonObject>() == false);
+    CHECK(cvariant.is<JsonObjectConst>() == false);
+    CHECK(cvariant.is<int>() == false);
+    CHECK(cvariant.is<float>() == false);
+    CHECK(cvariant.is<bool>() == false);
+    CHECK(cvariant.is<const char *>() == false);
+    CHECK(cvariant.is<MYENUM2>() == false);
+  }
+
+  SECTION("linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
+
+    CHECK(cvariant.is<JsonObjectConst>() == true);
+    CHECK(cvariant.is<JsonVariantConst>() == true);
+    CHECK(cvariant.is<JsonObject>() == false);
+    CHECK(cvariant.is<JsonVariant>() == false);
+    CHECK(cvariant.is<JsonArray>() == false);
+    CHECK(cvariant.is<JsonArrayConst>() == false);
+    CHECK(cvariant.is<int>() == false);
+    CHECK(cvariant.is<float>() == false);
+    CHECK(cvariant.is<bool>() == false);
+    CHECK(cvariant.is<const char *>() == false);
+    CHECK(cvariant.is<MYENUM2>() == false);
+  }
+
+  SECTION("linked int") {
+    StaticJsonDocument<1024> doc2;
+    doc2.set(42);
+    variant.link(doc2);
+
+    CHECK(cvariant.is<JsonObjectConst>() == false);
+    CHECK(cvariant.is<JsonVariantConst>() == true);
+    CHECK(cvariant.is<JsonObject>() == false);
+    CHECK(cvariant.is<JsonVariant>() == false);
+    CHECK(cvariant.is<JsonArray>() == false);
+    CHECK(cvariant.is<JsonArrayConst>() == false);
+    CHECK(cvariant.is<int>() == true);
+    CHECK(cvariant.is<float>() == false);
+    CHECK(cvariant.is<bool>() == false);
+    CHECK(cvariant.is<const char *>() == false);
+    CHECK(cvariant.is<MYENUM2>() == true);
+  }
 }

extras/tests/JsonVariant/isnull.cpp

@@ -9,17 +9,17 @@ TEST_CASE("JsonVariant::isNull()") {
   DynamicJsonDocument doc(4096);
   JsonVariant variant = doc.to<JsonVariant>();
 
-  SECTION("return true when Undefined") {
+  SECTION("returns true when Undefined") {
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return false when Integer") {
+  SECTION("returns false when Integer") {
     variant.set(42);
 
     REQUIRE(variant.isNull() == false);
   }
 
-  SECTION("return false when EmptyArray") {
+  SECTION("returns false when EmptyArray") {
     DynamicJsonDocument doc2(4096);
     JsonArray array = doc2.to<JsonArray>();
 
@@ -27,7 +27,7 @@ TEST_CASE("JsonVariant::isNull()") {
     REQUIRE(variant.isNull() == false);
   }
 
-  SECTION("return false when EmptyObject") {
+  SECTION("returns false when EmptyObject") {
     DynamicJsonDocument doc2(4096);
     JsonObject obj = doc2.to<JsonObject>();
 
@@ -35,41 +35,54 @@ TEST_CASE("JsonVariant::isNull()") {
     REQUIRE(variant.isNull() == false);
   }
 
-  SECTION("return true after set(JsonArray())") {
+  SECTION("returns true after set(JsonArray())") {
     variant.set(JsonArray());
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return true after set(JsonObject())") {
+  SECTION("returns true after set(JsonObject())") {
     variant.set(JsonObject());
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return false after set('hello')") {
+  SECTION("returns false after set('hello')") {
     variant.set("hello");
     REQUIRE(variant.isNull() == false);
   }
 
-  SECTION("return true after set((char*)0)") {
+  SECTION("returns true after set((char*)0)") {
     variant.set(static_cast<char*>(0));
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return true after set((const char*)0)") {
+  SECTION("returns true after set((const char*)0)") {
     variant.set(static_cast<const char*>(0));
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return true after set(serialized((char*)0))") {
+  SECTION("returns true after set(serialized((char*)0))") {
     variant.set(serialized(static_cast<char*>(0)));
     REQUIRE(variant.isNull() == true);
   }
 
-  SECTION("return true after set(serialized((const char*)0))") {
+  SECTION("returns true after set(serialized((const char*)0))") {
     variant.set(serialized(static_cast<const char*>(0)));
     REQUIRE(variant.isNull() == true);
   }
 
+  SECTION("returns true for a linked null") {
+    StaticJsonDocument<128> doc2;
+    variant.link(doc2);
+    CHECK(variant.isNull() == true);
+  }
+
+  SECTION("returns false for a linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2[0] = 42;
+    variant.link(doc2);
+    CHECK(variant.isNull() == false);
+  }
+
   SECTION("works with JsonVariantConst") {
     variant.set(42);
 

extras/tests/JsonVariant/link.cpp

@@ -0,0 +1,77 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonVariant::link()") {
+  StaticJsonDocument<1024> doc1, doc2;
+  JsonVariant variant = doc1.to<JsonVariant>();
+
+  SECTION("JsonVariant::link(JsonDocument&)") {
+    doc2["hello"] = "world";
+
+    variant.link(doc2);
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+    CHECK(variant.memoryUsage() == 0);
+
+    // altering the linked document should change the result
+    doc2["hello"] = "WORLD!";
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"WORLD!\"}");
+  }
+
+  SECTION("JsonVariant::link(MemberProxy)") {
+    doc2["obj"]["hello"] = "world";
+
+    variant.link(doc2["obj"]);
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+    CHECK(variant.memoryUsage() == 0);
+
+    // altering the linked document should change the result
+    doc2["obj"]["hello"] = "WORLD!";
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"WORLD!\"}");
+  }
+
+  SECTION("JsonVariant::link(ElementProxy)") {
+    doc2[0]["hello"] = "world";
+
+    variant.link(doc2[0]);
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+    CHECK(variant.memoryUsage() == 0);
+
+    // altering the linked document should change the result
+    doc2[0]["hello"] = "WORLD!";
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"WORLD!\"}");
+  }
+
+  SECTION("target is unbound") {
+    JsonVariant unbound;
+    variant["hello"] = "world";
+
+    variant.link(unbound);
+
+    CHECK(variant.isUnbound() == false);
+    CHECK(variant.isNull() == true);
+    CHECK(variant.memoryUsage() == 0);
+    CHECK(variant.size() == 0);
+  }
+
+  SECTION("variant is unbound") {
+    JsonVariant unbound;
+    doc2["hello"] = "world";
+
+    unbound.link(doc2);
+
+    CHECK(unbound.isUnbound() == true);
+    CHECK(unbound.isNull() == true);
+    CHECK(unbound.memoryUsage() == 0);
+    CHECK(unbound.size() == 0);
+  }
+}

extras/tests/JsonVariant/memoryUsage.cpp

@@ -38,4 +38,12 @@ TEST_CASE("JsonVariant::memoryUsage()") {
     REQUIRE(var.memoryUsage() == 6);
     REQUIRE(var.memoryUsage() == doc.memoryUsage());
   }
+
+  SECTION("ignore size of linked document") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+    CHECK(var.memoryUsage() == 0);
+    CHECK(var.memoryUsage() == doc.memoryUsage());
+  }
 }

extras/tests/JsonVariant/nesting.cpp

@@ -28,4 +28,12 @@ TEST_CASE("JsonVariant::nesting()") {
     var.to<JsonArray>();
     REQUIRE(var.nesting() == 1);
   }
+
+  SECTION("return depth of linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2[0][0] = 42;
+    var.link(doc2);
+
+    CHECK(var.nesting() == 2);
+  }
 }

extras/tests/JsonVariant/or.cpp

@@ -156,4 +156,12 @@ TEST_CASE("JsonVariant::operator|()") {
     int result = variant | 42;
     REQUIRE(result == 42);
   }
+
+  SECTION("linked int | int") {
+    StaticJsonDocument<128> doc2;
+    doc2.set(42);
+    variant.link(doc2);
+    int result = variant | 666;
+    CHECK(result == 42);
+  }
 }

extras/tests/JsonVariant/remove.cpp

@@ -39,4 +39,24 @@ TEST_CASE("JsonVariant::remove()") {
 
     REQUIRE(var.as<std::string>() == "{\"a\":1}");
   }
+
+  SECTION("linked array") {
+    StaticJsonDocument<128> doc2;
+    doc2[0] = 42;
+    var.link(doc2);
+
+    var.remove(0);
+
+    CHECK(var.as<std::string>() == "[42]");
+  }
+
+  SECTION("linked object") {
+    StaticJsonDocument<128> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    var.remove("hello");
+
+    CHECK(var.as<std::string>() == "{\"hello\":\"world\"}");
+  }
 }

extras/tests/JsonVariant/set.cpp

@@ -155,18 +155,21 @@ TEST_CASE("JsonVariant::set() with not enough memory") {
   }
 }
 
-TEST_CASE("JsonVariant::set(DynamicJsonDocument)") {
-  DynamicJsonDocument doc1(1024);
-  doc1["hello"] = "world";
+TEST_CASE("Copy/link from other document") {
+  StaticJsonDocument<1024> doc1, doc2;
+  JsonVariant variant = doc1.to<JsonVariant>();
 
-  DynamicJsonDocument doc2(1024);
-  JsonVariant v = doc2.to<JsonVariant>();
+  SECTION("JsonVariant::set(JsonDocument&)") {
+    doc2["hello"] = "world";
 
-  // Should copy the doc
-  v.set(doc1);
-  doc1.clear();
+    variant.set(doc2);
 
-  std::string json;
-  serializeJson(doc2, json);
-  REQUIRE(json == "{\"hello\":\"world\"}");
+    CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+    CHECK(variant.memoryUsage() == JSON_OBJECT_SIZE(1));
+
+    // altering the copied document should change the result
+    doc2["hello"] = "WORLD!";
+
+    CHECK(variant.as<std::string>() == "{\"hello\":\"world\"}");
+  }
 }

extras/tests/JsonVariant/size.cpp

@@ -0,0 +1,53 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonVariant::size()") {
+  DynamicJsonDocument doc(4096);
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  SECTION("unbound reference") {
+    JsonVariant unbound;
+
+    CHECK(unbound.size() == 0);
+  }
+
+  SECTION("int") {
+    variant.set(42);
+
+    CHECK(variant.size() == 0);
+  }
+
+  SECTION("string") {
+    variant.set("hello");
+
+    CHECK(variant.size() == 0);
+  }
+
+  SECTION("object") {
+    variant["a"] = 1;
+    variant["b"] = 2;
+
+    CHECK(variant.size() == 2);
+  }
+
+  SECTION("linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    variant.link(doc2);
+
+    CHECK(variant.size() == 1);
+  }
+
+  SECTION("linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2.add(1);
+    doc2.add(2);
+    variant.link(doc2);
+
+    CHECK(variant.size() == 2);
+  }
+}

extras/tests/JsonVariant/subscript.cpp

@@ -129,6 +129,44 @@ TEST_CASE("JsonVariant::operator[]") {
     REQUIRE(std::string("world") == variant[vla]);
   }
 #endif
+
+  SECTION("get value from linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    CHECK(var["hello"].as<std::string>() == "world");
+  }
+
+  SECTION("set value to linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    var["tutu"] = "toto";  // no-op
+
+    CHECK(doc.as<std::string>() == "{\"hello\":\"world\"}");
+    CHECK(doc2.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+
+  SECTION("get value from linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2.add(42);
+    var.link(doc2);
+
+    CHECK(var[0].as<int>() == 42);
+  }
+
+  SECTION("set value to linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2.add(42);
+    var.link(doc2);
+
+    var[0] = 666;  // no-op
+
+    CHECK(doc.as<std::string>() == "[42]");
+    CHECK(doc2.as<std::string>() == "[42]");
+  }
 }
 
 TEST_CASE("JsonVariantConst::operator[]") {
@@ -201,4 +239,20 @@ TEST_CASE("JsonVariantConst::operator[]") {
     REQUIRE(var.is<JsonObject>() == false);
     REQUIRE(value == 0);
   }
+
+  SECTION("get value from linked object") {
+    StaticJsonDocument<1024> doc2;
+    doc2["hello"] = "world";
+    var.link(doc2);
+
+    CHECK(cvar["hello"].as<std::string>() == "world");
+  }
+
+  SECTION("get value from linked array") {
+    StaticJsonDocument<1024> doc2;
+    doc2.add(42);
+    var.link(doc2);
+
+    CHECK(cvar[0].as<int>() == 42);
+  }
 }

src/ArduinoJson/Array/ArrayRef.hpp

@@ -207,7 +207,7 @@ struct Converter<ArrayRef> {
 
   static bool checkJson(VariantRef src) {
     VariantData* data = getData(src);
-    return data && data->isArray();
+    return data && data->isArrayStrict();
   }
 };
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Array/ElementProxy.hpp

@@ -92,6 +92,10 @@ class ElementProxy : public VariantOperators<ElementProxy<TArray> >,
     return getOrAddUpstreamElement().template to<T>();
   }
 
+  FORCE_INLINE void link(VariantConstRef value) const {
+    getOrAddUpstreamElement().link(value);
+  }
+
   // Replaces the value
   //
   // bool set(const TValue&)

src/ArduinoJson/Object/MemberProxy.hpp

@@ -117,6 +117,10 @@ class MemberProxy : public VariantOperators<MemberProxy<TObject, TStringRef> >,
     getUpstreamMember().remove(key);
   }
 
+  FORCE_INLINE void link(VariantConstRef value) {
+    getOrAddUpstreamMember().link(value);
+  }
+
   template <typename TValue>
   FORCE_INLINE typename VariantTo<TValue>::type to() {
     return getOrAddUpstreamMember().template to<TValue>();

src/ArduinoJson/Object/ObjectRef.hpp

@@ -276,7 +276,7 @@ struct Converter<ObjectRef> {
 
   static bool checkJson(VariantRef src) {
     VariantData* data = getData(src);
-    return data && data->isObject();
+    return data && data->isObjectStrict();
   }
 };
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Variant/VariantContent.hpp

@@ -31,6 +31,8 @@ enum {
   VALUE_IS_SIGNED_INTEGER = 0x0A,
   VALUE_IS_FLOAT = 0x0C,
 
+  VALUE_IS_POINTER = 0x10,
+
   COLLECTION_MASK = 0x60,
   VALUE_IS_OBJECT = 0x20,
   VALUE_IS_ARRAY = 0x40,
@@ -49,6 +51,7 @@ union VariantContent {
   UInt asUnsignedInteger;
   Integer asSignedInteger;
   CollectionData asCollection;
+  const class VariantData *asPointer;
   struct {
     const char *data;
     size_t size;

src/ArduinoJson/Variant/VariantData.hpp

@@ -68,6 +68,10 @@ class VariantData {
       case VALUE_IS_BOOLEAN:
         return visitor.visitBoolean(_content.asBoolean != 0);
 
+      case VALUE_IS_POINTER:
+        ARDUINOJSON_ASSERT(_content.asPointer != 0);
+        return _content.asPointer->accept(visitor);
+
       default:
         return visitor.visitNull();
     }
@@ -84,24 +88,35 @@ class VariantData {
   bool asBoolean() const;
 
   CollectionData *asArray() {
-    return isArray() ? &_content.asCollection : 0;
+    return isArrayStrict() ? &_content.asCollection : 0;
   }
 
   const CollectionData *asArray() const {
+    if (isPointer())
+      return _content.asPointer->asArray();
     return const_cast<VariantData *>(this)->asArray();
   }
 
   CollectionData *asObject() {
-    return isObject() ? &_content.asCollection : 0;
+    return isObjectStrict() ? &_content.asCollection : 0;
   }
 
   const CollectionData *asObject() const {
+    if (isPointer())
+      return _content.asPointer->asObject();
     return const_cast<VariantData *>(this)->asObject();
   }
 
   bool copyFrom(const VariantData &src, MemoryPool *pool);
 
   bool isArray() const {
+    if (isPointer())
+      return _content.asPointer->isArray();
+    else
+      return isArrayStrict();
+  }
+
+  bool isArrayStrict() const {
     return (_flags & VALUE_IS_ARRAY) != 0;
   }
 
@@ -113,8 +128,14 @@ class VariantData {
     return (_flags & COLLECTION_MASK) != 0;
   }
 
+  bool isPointer() const {
+    return type() == VALUE_IS_POINTER;
+  }
+
   template <typename T>
   bool isInteger() const {
+    if (isPointer())
+      return _content.asPointer->isInteger<T>();
     switch (type()) {
       case VALUE_IS_UNSIGNED_INTEGER:
         return canConvertNumber<T>(_content.asUnsignedInteger);
@@ -136,10 +157,18 @@ class VariantData {
   }
 
   bool isObject() const {
+    if (isPointer())
+      return _content.asPointer->isObject();
+    return isObjectStrict();
+  }
+
+  bool isObjectStrict() const {
     return (_flags & VALUE_IS_OBJECT) != 0;
   }
 
   bool isNull() const {
+    if (isPointer())
+      return _content.asPointer->isNull();
     return type() == VALUE_IS_NULL;
   }
 
@@ -148,13 +177,13 @@ class VariantData {
   }
 
   void remove(size_t index) {
-    if (isArray())
+    if (isArrayStrict())
       _content.asCollection.removeElement(index);
   }
 
   template <typename TAdaptedString>
   void remove(TAdaptedString key) {
-    if (isObject())
+    if (isObjectStrict())
       _content.asCollection.removeMember(key);
   }
 
@@ -208,6 +237,12 @@ class VariantData {
     setType(VALUE_IS_NULL);
   }
 
+  void setPointer(const VariantData *p) {
+    ARDUINOJSON_ASSERT(p);
+    setType(VALUE_IS_POINTER);
+    _content.asPointer = p;
+  }
+
   void setString(String s) {
     ARDUINOJSON_ASSERT(s);
     if (s.isLinked())
@@ -246,36 +281,42 @@ class VariantData {
   }
 
   size_t nesting() const {
+    if (isPointer())
+      return _content.asPointer->nesting();
     return isCollection() ? _content.asCollection.nesting() : 0;
   }
 
   size_t size() const {
+    if (isPointer())
+      return _content.asPointer->size();
     return isCollection() ? _content.asCollection.size() : 0;
   }
 
   VariantData *addElement(MemoryPool *pool) {
     if (isNull())
       toArray();
-    if (!isArray())
+    if (!isArrayStrict())
       return 0;
     return _content.asCollection.addElement(pool);
   }
 
   VariantData *getElement(size_t index) const {
-    return isArray() ? _content.asCollection.getElement(index) : 0;
+    const CollectionData *col = asArray();
+    return col ? col->getElement(index) : 0;
   }
 
   VariantData *getOrAddElement(size_t index, MemoryPool *pool) {
     if (isNull())
       toArray();
-    if (!isArray())
+    if (!isArrayStrict())
       return 0;
     return _content.asCollection.getOrAddElement(index, pool);
   }
 
   template <typename TAdaptedString>
   VariantData *getMember(TAdaptedString key) const {
-    return isObject() ? _content.asCollection.getMember(key) : 0;
+    const CollectionData *col = asObject();
+    return col ? col->getMember(key) : 0;
   }
 
   template <typename TAdaptedString, typename TStoragePolicy>
@@ -283,7 +324,7 @@ class VariantData {
                               TStoragePolicy storage_policy) {
     if (isNull())
       toObject();
-    if (!isObject())
+    if (!isObjectStrict())
       return 0;
     return _content.asCollection.getOrAddMember(key, pool, storage_policy);
   }

src/ArduinoJson/Variant/VariantImpl.hpp

@@ -29,6 +29,8 @@ inline T VariantData::asIntegral() const {
       return parseNumber<T>(_content.asString.data);
     case VALUE_IS_FLOAT:
       return convertNumber<T>(_content.asFloat);
+    case VALUE_IS_POINTER:
+      return _content.asPointer->asIntegral<T>();
     default:
       return 0;
   }
@@ -45,6 +47,8 @@ inline bool VariantData::asBoolean() const {
       return _content.asFloat != 0;
     case VALUE_IS_NULL:
       return false;
+    case VALUE_IS_POINTER:
+      return _content.asPointer->asBoolean();
     default:
       return true;
   }
@@ -65,6 +69,8 @@ inline T VariantData::asFloat() const {
       return parseNumber<T>(_content.asString.data);
     case VALUE_IS_FLOAT:
       return static_cast<T>(_content.asFloat);
+    case VALUE_IS_POINTER:
+      return _content.asPointer->asFloat<T>();
     default:
       return 0;
   }
@@ -78,6 +84,8 @@ inline String VariantData::asString() const {
     case VALUE_IS_OWNED_STRING:
       return String(_content.asString.data, _content.asString.size,
                     String::Copied);
+    case VALUE_IS_POINTER:
+      return _content.asPointer->asString();
     default:
       return String();
   }
@@ -181,4 +189,13 @@ bool CopyStringStoragePolicy::store(TAdaptedString str, MemoryPool *pool,
   return copy != 0;
 }
 
+inline void VariantRef::link(VariantConstRef target) {
+  if (!_data)
+    return;
+  if (target._data)
+    _data->setPointer(target._data);
+  else
+    _data->setNull();
+}
+
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Variant/VariantRef.hpp

@@ -198,6 +198,8 @@ class VariantRef : public VariantRefBase<VariantData>,
   template <typename TString>
   FORCE_INLINE VariantRef getOrAddMember(const TString &) const;
 
+  void link(class VariantConstRef var);
+
   FORCE_INLINE void remove(size_t index) const {
     if (_data)
       _data->remove(index);