Fixed JsonBuffer::parse() nesting limit (fixes #693)

CHANGELOG.md

@@ -1,6 +1,12 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Fixed `JsonBuffer::parse()` not respecting nesting limit correctly (issue #693)
+* Fixed inconsistencies in nesting level counting (PR #695 from Zhenyu Wu)
+
 v5.13.1
 -------
 

src/ArduinoJson/Deserialization/JsonParser.hpp

@@ -44,7 +44,6 @@ class JsonParser {
 
   const char *parseString();
   bool parseAnythingTo(JsonVariant *destination);
-  FORCE_INLINE bool parseAnythingToUnsafe(JsonVariant *destination);
 
   inline bool parseArrayTo(JsonVariant *destination);
   inline bool parseObjectTo(JsonVariant *destination);

src/ArduinoJson/Deserialization/JsonParserImpl.hpp

@@ -20,17 +20,6 @@ template <typename TReader, typename TWriter>
 inline bool
 ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseAnythingTo(
     JsonVariant *destination) {
-  if (_nestingLimit == 0) return false;
-  _nestingLimit--;
-  bool success = parseAnythingToUnsafe(destination);
-  _nestingLimit++;
-  return success;
-}
-
-template <typename TReader, typename TWriter>
-inline bool
-ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseAnythingToUnsafe(
-    JsonVariant *destination) {
   skipSpacesAndComments(_reader);
 
   switch (_reader.current()) {
@@ -48,6 +37,9 @@ ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseAnythingToUnsafe(
 template <typename TReader, typename TWriter>
 inline ArduinoJson::JsonArray &
 ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseArray() {
+  if (_nestingLimit == 0) return JsonArray::invalid();
+  _nestingLimit--;
+
   // Create an empty array
   JsonArray &array = _buffer->createArray();
 
@@ -69,6 +61,7 @@ ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseArray() {
 
 SUCCESS_EMPTY_ARRAY:
 SUCCES_NON_EMPTY_ARRAY:
+  _nestingLimit++;
   return array;
 
 ERROR_INVALID_VALUE:
@@ -91,6 +84,9 @@ inline bool ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseArrayTo(
 template <typename TReader, typename TWriter>
 inline ArduinoJson::JsonObject &
 ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseObject() {
+  if (_nestingLimit == 0) return JsonObject::invalid();
+  _nestingLimit--;
+
   // Create an empty object
   JsonObject &object = _buffer->createObject();
 
@@ -117,6 +113,7 @@ ArduinoJson::Internals::JsonParser<TReader, TWriter>::parseObject() {
 
 SUCCESS_EMPTY_OBJECT:
 SUCCESS_NON_EMPTY_OBJECT:
+  _nestingLimit++;
   return object;
 
 ERROR_INVALID_KEY:

test/JsonBuffer/nestingLimit.cpp

@@ -5,44 +5,62 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-bool tryParseArray(const char *json, uint8_t nestingLimit) {
+#define SHOULD_WORK(expression) REQUIRE(true == expression.success());
-  DynamicJsonBuffer buffer;
+#define SHOULD_FAIL(expression) REQUIRE(false == expression.success());
-  return buffer.parseArray(json, nestingLimit).success();
-}
-
-bool tryParseObject(const char *json, uint8_t nestingLimit) {
-  DynamicJsonBuffer buffer;
-  return buffer.parseObject(json, nestingLimit).success();
-}
 
 TEST_CASE("JsonParser nestingLimit") {
-  SECTION("ParseArrayWithNestingLimit0") {
+  DynamicJsonBuffer jb;
-    REQUIRE(true == tryParseArray("[]", 0));
+
-    REQUIRE(false == tryParseArray("[[]]", 0));
+  SECTION("parseArray()") {
+    SECTION("limit = 0") {
+      SHOULD_FAIL(jb.parseArray("[]", 0));
+    }
+
+    SECTION("limit = 1") {
+      SHOULD_WORK(jb.parseArray("[]", 1));
+      SHOULD_FAIL(jb.parseArray("[[]]", 1));
+    }
+
+    SECTION("limit = 2") {
+      SHOULD_WORK(jb.parseArray("[[]]", 2));
+      SHOULD_FAIL(jb.parseArray("[[[]]]", 2));
+    }
   }
 
-  SECTION("ParseArrayWithNestingLimit1") {
+  SECTION("parseObject()") {
-    REQUIRE(true == tryParseArray("[[]]", 1));
+    SECTION("limit = 0") {
-    REQUIRE(false == tryParseArray("[[[]]]", 1));
+      SHOULD_FAIL(jb.parseObject("{}", 0));
+    }
+
+    SECTION("limit = 1") {
+      SHOULD_WORK(jb.parseObject("{\"key\":42}", 1));
+      SHOULD_FAIL(jb.parseObject("{\"key\":{\"key\":42}}", 1));
+    }
+
+    SECTION("limit = 2") {
+      SHOULD_WORK(jb.parseObject("{\"key\":{\"key\":42}}", 2));
+      SHOULD_FAIL(jb.parseObject("{\"key\":{\"key\":{\"key\":42}}}", 2));
+    }
   }
 
-  SECTION("ParseArrayWithNestingLimit2") {
+  SECTION("parse()") {
-    REQUIRE(true == tryParseArray("[[[]]]", 2));
+    SECTION("limit = 0") {
-    REQUIRE(false == tryParseArray("[[[[]]]]", 2));
+      SHOULD_WORK(jb.parse("\"toto\"", 0));
-  }
+      SHOULD_WORK(jb.parse("123", 0));
+      SHOULD_WORK(jb.parse("true", 0));
+      SHOULD_FAIL(jb.parse("[]", 0));
+      SHOULD_FAIL(jb.parse("{}", 0));
+      SHOULD_FAIL(jb.parse("[\"toto\"]", 0));
+      SHOULD_FAIL(jb.parse("{\"toto\":1}", 0));
+    }
 
-  SECTION("ParseObjectWithNestingLimit0") {
+    SECTION("limit = 1") {
-    REQUIRE(true == tryParseObject("{}", 0));
+      SHOULD_WORK(jb.parse("[\"toto\"]", 1));
-    REQUIRE(false == tryParseObject("{\"key\":{}}", 0));
+      SHOULD_WORK(jb.parse("{\"toto\":1}", 1));
-  }
+      SHOULD_FAIL(jb.parse("{\"toto\":{}}", 1));
-
+      SHOULD_FAIL(jb.parse("{\"toto\":[]}", 1));
-  SECTION("ParseObjectWithNestingLimit1") {
+      SHOULD_FAIL(jb.parse("[[\"toto\"]]", 1));
-    REQUIRE(true == tryParseObject("{\"key\":{}}", 1));
+      SHOULD_FAIL(jb.parse("[{\"toto\":1}]", 1));
-    REQUIRE(false == tryParseObject("{\"key\":{\"key\":{}}}", 1));
+    }
-  }
-
-  SECTION("ParseObjectWithNestingLimit2") {
-    REQUIRE(true == tryParseObject("{\"key\":{\"key\":{}}}", 2));
-    REQUIRE(false == tryParseObject("{\"key\":{\"key\":{\"key\":{}}}}", 2));
   }
 }