Create or assign a JsonDocument from a JsonArray/JsonObject/JsonVariant

CHANGELOG.md

@@ -15,6 +15,9 @@ HEAD
 * Replaced `JsonDocument::nestingLimit` with an additional parameter
   to `deserializeJson()` and `deserializeMsgPack()`
 * Fixed uninitialized variant in `JsonDocument`
+* Fixed `StaticJsonDocument` copy constructor and copy assignment
+* The copy constructor of `DynamicJsonDocument` chooses the capacity according to the memory usage of the source, not from the capacity of the source.
+* Added the ability to create/assign a `StaticJsonDocument`/`DynamicJsonDocument` from a `JsonArray`/`JsonObject`/`JsonVariant`
 * Added `JsonDocument::isNull()`
 
 > ### BREAKING CHANGES

src/ArduinoJson/Document/DynamicJsonDocument.hpp

@@ -13,16 +13,24 @@ namespace ARDUINOJSON_NAMESPACE {
 class DynamicJsonDocument : public JsonDocument {
  public:
   explicit DynamicJsonDocument(size_t capa)
-      : JsonDocument(allocPool(addPadding(capa))) {}
+      : JsonDocument(allocPool(capa)) {}
 
   DynamicJsonDocument(const DynamicJsonDocument& src)
-      : JsonDocument(allocPool(src.capacity())) {
-    copy(src);
+      : JsonDocument(allocPool(src.memoryUsage())) {
+    set(src);
   }
 
-  DynamicJsonDocument(const JsonDocument& src)
-      : JsonDocument(allocPool(src.capacity())) {
-    copy(src);
+  template <typename T>
+  DynamicJsonDocument(const T& src,
+                      typename enable_if<IsVisitable<T>::value>::type* = 0)
+      : JsonDocument(allocPool(src.memoryUsage())) {
+    set(src);
+  }
+
+  // disambiguate
+  DynamicJsonDocument(VariantRef src)
+      : JsonDocument(allocPool(src.memoryUsage())) {
+    set(src);
   }
 
   ~DynamicJsonDocument() {
@@ -31,19 +39,20 @@ class DynamicJsonDocument : public JsonDocument {
 
   DynamicJsonDocument& operator=(const DynamicJsonDocument& src) {
     reallocPoolIfTooSmall(src.memoryUsage());
-    copy(src);
+    set(src);
     return *this;
   }
 
   template <typename T>
-  DynamicJsonDocument& operator=(const JsonDocument& src) {
+  DynamicJsonDocument& operator=(const T& src) {
     reallocPoolIfTooSmall(src.memoryUsage());
-    copy(src);
+    set(src);
     return *this;
   }
 
  private:
-  MemoryPool allocPool(size_t capa) {
+  MemoryPool allocPool(size_t requiredSize) {
+    size_t capa = addPadding(requiredSize);
     return MemoryPool(reinterpret_cast<char*>(malloc(capa)), capa);
   }
 

src/ArduinoJson/Document/JsonDocument.hpp

@@ -5,6 +5,7 @@
 #pragma once
 
 #include "../Memory/MemoryPool.hpp"
+#include "../Object/ObjectRef.hpp"
 #include "../Variant/VariantRef.hpp"
 #include "../Variant/VariantTo.hpp"
 
@@ -53,6 +54,16 @@ class JsonDocument : public Visitable {
     return _pool.capacity();
   }
 
+  bool set(const JsonDocument& src) {
+    return to<VariantRef>().set(src.as<VariantRef>());
+  }
+
+  template <typename T>
+  typename enable_if<!is_base_of<JsonDocument, T>::value, bool>::type set(
+      const T& src) {
+    return to<VariantRef>().set(src);
+  }
+
   template <typename T>
   typename VariantTo<T>::type to() {
     clear();

src/ArduinoJson/Document/StaticJsonDocument.hpp

@@ -16,13 +16,31 @@ class StaticJsonDocument : public JsonDocument {
  public:
   StaticJsonDocument() : JsonDocument(_buffer, ACTUAL_CAPACITY) {}
 
-  StaticJsonDocument(const JsonDocument& src)
+  StaticJsonDocument(const StaticJsonDocument& src)
       : JsonDocument(_buffer, ACTUAL_CAPACITY) {
-    copy(src);
+    set(src);
   }
 
-  StaticJsonDocument operator=(const JsonDocument& src) {
-    copy(src);
+  template <typename T>
+  StaticJsonDocument(const T& src,
+                     typename enable_if<IsVisitable<T>::value>::type* = 0)
+      : JsonDocument(_buffer, ACTUAL_CAPACITY) {
+    set(src);
+  }
+
+  // disambiguate
+  StaticJsonDocument(VariantRef src) : JsonDocument(_buffer, ACTUAL_CAPACITY) {
+    set(src);
+  }
+
+  StaticJsonDocument operator=(const StaticJsonDocument& src) {
+    set(src);
+    return *this;
+  }
+
+  template <typename T>
+  StaticJsonDocument operator=(const T& src) {
+    set(src);
     return *this;
   }
 

src/ArduinoJson/Variant/VariantAs.hpp

@@ -77,6 +77,14 @@ variantAs(const VariantData* _data) {
   return _data != 0 ? _data->asString() : 0;
 }
 
+template <typename T>
+inline typename enable_if<is_same<ArrayConstRef, T>::value, T>::type variantAs(
+    const VariantData* _data);
+
+template <typename T>
+inline typename enable_if<is_same<ObjectConstRef, T>::value, T>::type variantAs(
+    const VariantData* _data);
+
 template <typename T>
 inline typename enable_if<is_same<VariantConstRef, T>::value, T>::type
 variantAs(const VariantData* _data);

src/ArduinoJson/Variant/VariantAsImpl.hpp

@@ -5,10 +5,23 @@
 #pragma once
 
 #include "../Serialization/DynamicStringWriter.hpp"
+#include "VariantFunctions.hpp"
 #include "VariantRef.hpp"
 
 namespace ARDUINOJSON_NAMESPACE {
 
+template <typename T>
+inline typename enable_if<is_same<ArrayConstRef, T>::value, T>::type variantAs(
+    const VariantData* _data) {
+  return ArrayConstRef(variantAsArray(_data));
+}
+
+template <typename T>
+inline typename enable_if<is_same<ObjectConstRef, T>::value, T>::type variantAs(
+    const VariantData* _data) {
+  return ObjectConstRef(variantAsObject(_data));
+}
+
 template <typename T>
 inline typename enable_if<is_same<VariantConstRef, T>::value, T>::type
 variantAs(const VariantData* _data) {

src/ArduinoJson/Variant/VariantData.hpp

@@ -67,10 +67,7 @@ class VariantData {
   }
 
   CollectionData *asArray() {
-    if (type() == VALUE_IS_ARRAY)
-      return &_content.asCollection;
-    else
-      return 0;
+    return type() == VALUE_IS_ARRAY ? &_content.asCollection : 0;
   }
 
   const CollectionData *asArray() const {
@@ -78,10 +75,7 @@ class VariantData {
   }
 
   CollectionData *asObject() {
-    if (type() == VALUE_IS_OBJECT)
-      return &_content.asCollection;
-    else
-      return 0;
+    return type() == VALUE_IS_OBJECT ? &_content.asCollection : 0;
   }
 
   const CollectionData *asObject() const {

src/ArduinoJson/Variant/VariantFunctions.hpp

@@ -16,6 +16,10 @@ inline void variantAccept(const VariantData *var, Visitor &visitor) {
     visitor.visitNull();
 }
 
+inline const CollectionData *variantAsArray(const VariantData *var) {
+  return var != 0 ? var->asArray() : 0;
+}
+
 inline const CollectionData *variantAsObject(const VariantData *var) {
   return var != 0 ? var->asObject() : 0;
 }

test/JsonDocument/DynamicJsonDocument.cpp

@@ -5,6 +5,14 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+using ARDUINOJSON_NAMESPACE::addPadding;
+
+static void REQUIRE_JSON(JsonDocument& doc, const std::string& expected) {
+  std::string json;
+  serializeJson(doc, json);
+  REQUIRE(json == expected);
+}
+
 TEST_CASE("DynamicJsonDocument") {
   DynamicJsonDocument doc(4096);
 
@@ -74,20 +82,62 @@ TEST_CASE("DynamicJsonDocument") {
   }
 }
 
-TEST_CASE("DynamicJsonDocument copies") {
+TEST_CASE("DynamicJsonDocument constructor") {
   SECTION("Copy constructor") {
     DynamicJsonDocument doc1(1234);
     deserializeJson(doc1, "{\"hello\":\"world\"}");
 
     DynamicJsonDocument doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc2, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
 
-    REQUIRE(doc2.capacity() == doc1.capacity());
+    REQUIRE(doc2.capacity() == addPadding(doc1.memoryUsage()));
   }
 
+  SECTION("Construct from StaticJsonDocument") {
+    StaticJsonDocument<200> doc1;
+    deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+    DynamicJsonDocument doc2 = doc1;
+
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    REQUIRE(doc2.capacity() == addPadding(doc1.memoryUsage()));
+  }
+
+  SECTION("Construct from JsonObject") {
+    StaticJsonDocument<200> doc1;
+    JsonObject obj = doc1.to<JsonObject>();
+    obj["hello"] = "world";
+
+    DynamicJsonDocument doc2 = obj;
+
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    REQUIRE(doc2.capacity() == addPadding(doc1.memoryUsage()));
+  }
+
+  SECTION("Construct from JsonArray") {
+    StaticJsonDocument<200> doc1;
+    JsonArray arr = doc1.to<JsonArray>();
+    arr.add("hello");
+
+    DynamicJsonDocument doc2 = arr;
+
+    REQUIRE_JSON(doc2, "[\"hello\"]");
+    REQUIRE(doc2.capacity() == addPadding(doc1.memoryUsage()));
+  }
+
+  SECTION("Construct from JsonVariant") {
+    StaticJsonDocument<200> doc1;
+    deserializeJson(doc1, "42");
+
+    DynamicJsonDocument doc2 = doc1.as<JsonVariant>();
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == addPadding(doc1.memoryUsage()));
+  }
+}
+
+TEST_CASE("DynamicJsonDocument assignment") {
   SECTION("Copy assignment preserves the buffer when capacity is sufficient") {
     DynamicJsonDocument doc1(1234);
     deserializeJson(doc1, "{\"hello\":\"world\"}");
@@ -95,9 +145,7 @@ TEST_CASE("DynamicJsonDocument copies") {
     DynamicJsonDocument doc2(doc1.capacity());
     doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc2, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
     REQUIRE(doc2.capacity() == doc1.capacity());
   }
 
@@ -110,34 +158,52 @@ TEST_CASE("DynamicJsonDocument copies") {
     doc2 = doc1;
     REQUIRE(doc2.capacity() >= doc1.memoryUsage());
 
-    std::string json;
-    serializeJson(doc2, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
-  }
-
-  SECTION("Construct from StaticJsonDocument") {
-    StaticJsonDocument<200> sdoc;
-    deserializeJson(sdoc, "{\"hello\":\"world\"}");
-
-    DynamicJsonDocument ddoc = sdoc;
-
-    std::string json;
-    serializeJson(ddoc, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
-    REQUIRE(ddoc.capacity() == sdoc.capacity());
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
   }
 
   SECTION("Assign from StaticJsonDocument") {
-    DynamicJsonDocument ddoc(4096);
-    ddoc.to<JsonVariant>().set(666);
+    StaticJsonDocument<200> doc1;
+    deserializeJson(doc1, "{\"hello\":\"world\"}");
+    DynamicJsonDocument doc2(4096);
+    doc2.to<JsonVariant>().set(666);
 
-    StaticJsonDocument<200> sdoc;
-    deserializeJson(sdoc, "{\"hello\":\"world\"}");
+    doc2 = doc1;
 
-    ddoc = sdoc;
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+  }
 
-    std::string json;
-    serializeJson(ddoc, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+  SECTION("Assign from JsonObject") {
+    StaticJsonDocument<200> doc1;
+    JsonObject obj = doc1.to<JsonObject>();
+    obj["hello"] = "world";
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = obj;
+
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    REQUIRE(doc2.capacity() == 4096);
+  }
+
+  SECTION("Assign from JsonArray") {
+    StaticJsonDocument<200> doc1;
+    JsonArray arr = doc1.to<JsonArray>();
+    arr.add("hello");
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = arr;
+
+    REQUIRE_JSON(doc2, "[\"hello\"]");
+    REQUIRE(doc2.capacity() == 4096);
+  }
+
+  SECTION("Assign from JsonVariant") {
+    StaticJsonDocument<200> doc1;
+    deserializeJson(doc1, "42");
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = doc1.as<JsonVariant>();
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == 4096);
   }
 }

test/JsonDocument/StaticJsonDocument.cpp

@@ -5,6 +5,12 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+static void REQUIRE_JSON(JsonDocument& doc, const std::string& expected) {
+  std::string json;
+  serializeJson(doc, json);
+  REQUIRE(json == expected);
+}
+
 TEST_CASE("StaticJsonDocument") {
   SECTION("capacity()") {
     SECTION("matches template argument") {
@@ -36,67 +42,171 @@ TEST_CASE("StaticJsonDocument") {
 
     doc1 = doc2;
 
-    std::string json;
-    serializeJson(doc1, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+    REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
   }
 
-  SECTION("Copy constructor") {
-    StaticJsonDocument<200> doc1;
-    deserializeJson(doc1, "{\"hello\":\"world\"}");
+  SECTION("Contructor") {
+    SECTION("Copy constructor") {
+      StaticJsonDocument<200> doc1;
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
 
-    StaticJsonDocument<200> doc2 = doc1;
+      StaticJsonDocument<200> doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc2, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Construct from StaticJsonDocument of different size") {
+      StaticJsonDocument<300> doc1;
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+      StaticJsonDocument<200> doc2 = doc1;
+
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Construct from DynamicJsonDocument") {
+      DynamicJsonDocument doc1(4096);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+      StaticJsonDocument<200> doc2 = doc1;
+
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Construct from JsonObject") {
+      DynamicJsonDocument doc1(4096);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+      StaticJsonDocument<200> doc2 = doc1.as<JsonObject>();
+
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Construct from JsonArray") {
+      DynamicJsonDocument doc1(4096);
+      deserializeJson(doc1, "[\"hello\",\"world\"]");
+
+      StaticJsonDocument<200> doc2 = doc1.as<JsonArray>();
+
+      deserializeJson(doc1, "[\"HELLO\",\"WORLD\"]");
+      REQUIRE_JSON(doc2, "[\"hello\",\"world\"]");
+    }
+
+    SECTION("Construct from JsonVariant") {
+      DynamicJsonDocument doc1(4096);
+      deserializeJson(doc1, "42");
+
+      StaticJsonDocument<200> doc2 = doc1.as<JsonVariant>();
+
+      REQUIRE_JSON(doc2, "42");
+    }
   }
 
-  SECTION("Assign from StaticJsonDocument of different capacity") {
-    StaticJsonDocument<200> doc1;
-    StaticJsonDocument<300> doc2;
-    doc1.to<JsonVariant>().set(666);
-    deserializeJson(doc2, "{\"hello\":\"world\"}");
+  SECTION("Assignment") {
+    SECTION("Copy assignment") {
+      StaticJsonDocument<200> doc1, doc2;
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
 
-    doc1 = doc2;
+      doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc1, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
-  }
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
 
-  SECTION("Assign from DynamicJsonDocument") {
-    StaticJsonDocument<200> doc1;
-    DynamicJsonDocument doc2(4096);
-    doc1.to<JsonVariant>().set(666);
-    deserializeJson(doc2, "{\"hello\":\"world\"}");
+    SECTION("Assign from StaticJsonDocument of different capacity") {
+      StaticJsonDocument<200> doc1;
+      StaticJsonDocument<300> doc2;
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
 
-    doc1 = doc2;
+      doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc1, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
-  }
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
 
-  SECTION("Construct from StaticJsonDocument of different size") {
-    StaticJsonDocument<300> doc2;
-    deserializeJson(doc2, "{\"hello\":\"world\"}");
+    SECTION("Assign from DynamicJsonDocument") {
+      StaticJsonDocument<200> doc1;
+      DynamicJsonDocument doc2(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
 
-    StaticJsonDocument<200> doc1 = doc2;
+      doc2 = doc1;
 
-    std::string json;
-    serializeJson(doc1, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
-  }
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
 
-  SECTION("Construct from DynamicJsonDocument") {
-    DynamicJsonDocument doc2(4096);
-    deserializeJson(doc2, "{\"hello\":\"world\"}");
+    SECTION("Assign from JsonArray") {
+      StaticJsonDocument<200> doc1;
+      DynamicJsonDocument doc2(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "[\"hello\",\"world\"]");
 
-    StaticJsonDocument<200> doc1 = doc2;
+      doc2 = doc1.as<JsonArray>();
 
-    std::string json;
-    serializeJson(doc1, json);
-    REQUIRE(json == "{\"hello\":\"world\"}");
+      deserializeJson(doc1, "[\"HELLO\",\"WORLD\"]");
+      REQUIRE_JSON(doc2, "[\"hello\",\"world\"]");
+    }
+
+    SECTION("Assign from JsonArrayConst") {
+      StaticJsonDocument<200> doc1;
+      DynamicJsonDocument doc2(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "[\"hello\",\"world\"]");
+
+      doc2 = doc1.as<JsonArrayConst>();
+
+      deserializeJson(doc1, "[\"HELLO\",\"WORLD\"]");
+      REQUIRE_JSON(doc2, "[\"hello\",\"world\"]");
+    }
+
+    SECTION("Assign from JsonObject") {
+      StaticJsonDocument<200> doc1;
+      DynamicJsonDocument doc2(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+      doc2 = doc1.as<JsonObject>();
+
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Assign from JsonObjectConst") {
+      StaticJsonDocument<200> doc1;
+      DynamicJsonDocument doc2(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+      doc2 = doc1.as<JsonObjectConst>();
+
+      deserializeJson(doc1, "{\"HELLO\":\"WORLD\"}");
+      REQUIRE_JSON(doc2, "{\"hello\":\"world\"}");
+    }
+
+    SECTION("Assign from JsonVariant") {
+      DynamicJsonDocument doc1(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "42");
+
+      StaticJsonDocument<200> doc2;
+      doc2 = doc1.as<JsonVariant>();
+
+      REQUIRE_JSON(doc2, "42");
+    }
+
+    SECTION("Assign from JsonVariantConst") {
+      DynamicJsonDocument doc1(4096);
+      doc1.to<JsonVariant>().set(666);
+      deserializeJson(doc1, "42");
+
+      StaticJsonDocument<200> doc2;
+      doc2 = doc1.as<JsonVariantConst>();
+
+      REQUIRE_JSON(doc2, "42");
+    }
   }
 }