Replacing a value now releases the memory

test/JsonVariant/set.cpp

@@ -0,0 +1,146 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonVariant and strings") {
+  DynamicJsonDocument doc;
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  SECTION("stores const char* by reference") {
+    char str[16];
+
+    strcpy(str, "hello");
+    variant.set(static_cast<const char *>(str));
+    strcpy(str, "world");
+
+    REQUIRE(variant == "world");
+  }
+
+  SECTION("stores char* by copy") {
+    char str[16];
+
+    strcpy(str, "hello");
+    variant.set(str);
+    strcpy(str, "world");
+
+    REQUIRE(variant == "hello");
+  }
+
+  SECTION("stores unsigned char* by copy") {
+    char str[16];
+
+    strcpy(str, "hello");
+    variant.set(reinterpret_cast<unsigned char *>(str));
+    strcpy(str, "world");
+
+    REQUIRE(variant == "hello");
+  }
+
+  SECTION("stores signed char* by copy") {
+    char str[16];
+
+    strcpy(str, "hello");
+    variant.set(reinterpret_cast<signed char *>(str));
+    strcpy(str, "world");
+
+    REQUIRE(variant == "hello");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("stores VLA by copy") {
+    int n = 16;
+    char str[n];
+
+    strcpy(str, "hello");
+    variant.set(str);
+    strcpy(str, "world");
+
+    REQUIRE(variant == "hello");
+  }
+#endif
+
+  SECTION("stores std::string by copy") {
+    std::string str;
+
+    str = "hello";
+    variant.set(str);
+    str.replace(0, 5, "world");
+
+    REQUIRE(variant == "hello");
+  }
+}
+
+TEST_CASE("JsonVariant::set() should release string memory") {
+  DynamicJsonDocument doc;
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  variant.set(std::string("hello"));
+  REQUIRE(doc.memoryUsage() == JSON_STRING_SIZE(6));
+
+  SECTION("int") {
+    variant.set(-42);
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("unsigned int") {
+    variant.set(42U);
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("bool") {
+    variant.set(true);
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("float") {
+    variant.set(3.14);
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("const char*") {
+    variant.set("hello");
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("std::string") {
+    variant.set(std::string("X"));
+    REQUIRE(doc.memoryUsage() == JSON_STRING_SIZE(2));
+  }
+
+  SECTION("SerializedValue<const char*>") {
+    variant.set(serialized("[42]"));
+    REQUIRE(doc.memoryUsage() == 0);
+  }
+
+  SECTION("SerializedValue<std::string>") {
+    variant.set(serialized(std::string("42")));
+    REQUIRE(doc.memoryUsage() == JSON_STRING_SIZE(2));
+  }
+
+  SECTION("StringInMemoryPool") {
+    DeserializationError err =
+        deserializeJson(doc, std::string("{\"A\":\"hello\",\"A\":\"B\"}"));
+    REQUIRE(err == DeserializationError::Ok);
+    // it stores the key twice, but should release "hello"
+    REQUIRE(doc.memoryUsage() == JSON_OBJECT_SIZE(1) + 3 * JSON_STRING_SIZE(2));
+  }
+}
+
+TEST_CASE("JsonVariant with not enough memory") {
+  StaticJsonDocument<1> doc;
+
+  JsonVariant v = doc.to<JsonVariant>();
+
+  SECTION("std::string") {
+    v.set(std::string("hello"));
+    REQUIRE(v.isNull());
+  }
+
+  SECTION("Serialized<std::string>") {
+    v.set(serialized(std::string("hello")));
+    REQUIRE(v.isNull());
+  }
+}