From fbffadb2cf787129b539f9241c40418f7693e737 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Thu, 13 Feb 2020 16:54:18 +0100
Subject: [PATCH] Moved nesting decrement logic to class NestingLimit

---
 .../Deserialization/NestingLimit.hpp          | 20 ++++-
 .../Deserialization/deserialize.hpp           | 18 ++---
 src/ArduinoJson/Json/JsonDeserializer.hpp     | 74 ++++++++-----------
 .../MsgPack/MsgPackDeserializer.hpp           | 60 ++++++++-------
 4 files changed, 88 insertions(+), 84 deletions(-)

diff --git a/src/ArduinoJson/Deserialization/NestingLimit.hpp b/src/ArduinoJson/Deserialization/NestingLimit.hpp
index a5fa4357..8f33b6c7 100644
--- a/src/ArduinoJson/Deserialization/NestingLimit.hpp
+++ b/src/ArduinoJson/Deserialization/NestingLimit.hpp
@@ -5,13 +5,25 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
+#include <ArduinoJson/Polyfills/assert.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-struct NestingLimit {
-  NestingLimit() : value(ARDUINOJSON_DEFAULT_NESTING_LIMIT) {}
-  explicit NestingLimit(uint8_t n) : value(n) {}
+class NestingLimit {
+ public:
+  NestingLimit() : _value(ARDUINOJSON_DEFAULT_NESTING_LIMIT) {}
+  explicit NestingLimit(uint8_t n) : _value(n) {}
 
-  uint8_t value;
+  NestingLimit decrement() const {
+    ARDUINOJSON_ASSERT(_value > 0);
+    return NestingLimit(static_cast<uint8_t>(_value - 1));
+  }
+
+  bool reached() const {
+    return _value == 0;
+  }
+
+ private:
+  uint8_t _value;
 };
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Deserialization/deserialize.hpp b/src/ArduinoJson/Deserialization/deserialize.hpp
index 98435de9..f80f587b 100644
--- a/src/ArduinoJson/Deserialization/deserialize.hpp
+++ b/src/ArduinoJson/Deserialization/deserialize.hpp
@@ -15,9 +15,9 @@ namespace ARDUINOJSON_NAMESPACE {
 template <template <typename, typename> class TDeserializer, typename TReader,
           typename TWriter>
 TDeserializer<TReader, TWriter> makeDeserializer(MemoryPool &pool,
-                                                 TReader reader, TWriter writer,
-                                                 uint8_t nestingLimit) {
-  return TDeserializer<TReader, TWriter>(pool, reader, writer, nestingLimit);
+                                                 TReader reader,
+                                                 TWriter writer) {
+  return TDeserializer<TReader, TWriter>(pool, reader, writer);
 }
 
 // deserialize(JsonDocument&, const std::string&, NestingLimit, Filter);
@@ -34,8 +34,8 @@ deserialize(JsonDocument &doc, const TString &input, NestingLimit nestingLimit,
   doc.clear();
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), reader,
-             makeStringStorage(doc.memoryPool(), input), nestingLimit.value)
-      .parse(doc.data(), filter);
+             makeStringStorage(doc.memoryPool(), input))
+      .parse(doc.data(), filter, nestingLimit);
 }
 //
 // deserialize(JsonDocument&, char*, size_t, NestingLimit, Filter);
@@ -50,8 +50,8 @@ DeserializationError deserialize(JsonDocument &doc, TChar *input,
   doc.clear();
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), reader,
-             makeStringStorage(doc.memoryPool(), input), nestingLimit.value)
-      .parse(doc.data(), filter);
+             makeStringStorage(doc.memoryPool(), input))
+      .parse(doc.data(), filter, nestingLimit);
 }
 //
 // deserialize(JsonDocument&, std::istream&, NestingLimit, Filter);
@@ -64,8 +64,8 @@ DeserializationError deserialize(JsonDocument &doc, TStream &input,
   doc.clear();
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), reader,
-             makeStringStorage(doc.memoryPool(), input), nestingLimit.value)
-      .parse(doc.data(), filter);
+             makeStringStorage(doc.memoryPool(), input))
+      .parse(doc.data(), filter, nestingLimit);
 }
 
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/JsonDeserializer.hpp b/src/ArduinoJson/Json/JsonDeserializer.hpp
index 9c363d77..01603cc9 100644
--- a/src/ArduinoJson/Json/JsonDeserializer.hpp
+++ b/src/ArduinoJson/Json/JsonDeserializer.hpp
@@ -23,15 +23,13 @@ class JsonDeserializer {
 
  public:
   JsonDeserializer(MemoryPool &pool, TReader reader,
-                   TStringStorage stringStorage, uint8_t nestingLimit)
-      : _pool(&pool),
-        _stringStorage(stringStorage),
-        _nestingLimit(nestingLimit),
-        _latch(reader) {}
+                   TStringStorage stringStorage)
+      : _pool(&pool), _stringStorage(stringStorage), _latch(reader) {}
 
   template <typename TFilter>
-  DeserializationError parse(VariantData &variant, TFilter filter) {
-    DeserializationError err = parseVariant(variant, filter);
+  DeserializationError parse(VariantData &variant, TFilter filter,
+                             NestingLimit nestingLimit) {
+    DeserializationError err = parseVariant(variant, filter, nestingLimit);
 
     if (!err && _latch.last() != 0 && !variant.isEnclosed()) {
       // We don't detect trailing characters earlier, so we need to check now
@@ -59,22 +57,23 @@ class JsonDeserializer {
   }
 
   template <typename TFilter>
-  DeserializationError parseVariant(VariantData &variant, TFilter filter) {
+  DeserializationError parseVariant(VariantData &variant, TFilter filter,
+                                    NestingLimit nestingLimit) {
     DeserializationError err = skipSpacesAndComments();
     if (err) return err;
 
     switch (current()) {
       case '[':
         if (filter.allowArray())
-          return parseArray(variant.toArray(), filter);
+          return parseArray(variant.toArray(), filter, nestingLimit);
         else
-          return skipArray();
+          return skipArray(nestingLimit);
 
       case '{':
         if (filter.allowObject())
-          return parseObject(variant.toObject(), filter);
+          return parseObject(variant.toObject(), filter, nestingLimit);
         else
-          return skipObject();
+          return skipObject(nestingLimit);
 
       case '\"':
       case '\'':
@@ -91,16 +90,16 @@ class JsonDeserializer {
     }
   }
 
-  DeserializationError skipVariant() {
+  DeserializationError skipVariant(NestingLimit nestingLimit) {
     DeserializationError err = skipSpacesAndComments();
     if (err) return err;
 
     switch (current()) {
       case '[':
-        return skipArray();
+        return skipArray(nestingLimit);
 
       case '{':
-        return skipObject();
+        return skipObject(nestingLimit);
 
       case '\"':
       case '\'':
@@ -112,8 +111,9 @@ class JsonDeserializer {
   }
 
   template <typename TFilter>
-  DeserializationError parseArray(CollectionData &array, TFilter filter) {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
+  DeserializationError parseArray(CollectionData &array, TFilter filter,
+                                  NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
 
     // Check opening braket
     if (!eat('[')) return DeserializationError::InvalidInput;
@@ -135,14 +135,10 @@ class JsonDeserializer {
         if (!value) return DeserializationError::NoMemory;
 
         // 1 - Parse value
-        _nestingLimit--;
-        err = parseVariant(*value, memberFilter);
-        _nestingLimit++;
+        err = parseVariant(*value, memberFilter, nestingLimit.decrement());
         if (err) return err;
       } else {
-        _nestingLimit--;
-        err = skipVariant();
-        _nestingLimit++;
+        err = skipVariant(nestingLimit.decrement());
         if (err) return err;
       }
 
@@ -156,8 +152,8 @@ class JsonDeserializer {
     }
   }
 
-  DeserializationError skipArray() {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
+  DeserializationError skipArray(NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
 
     // Check opening braket
     if (!eat('[')) return DeserializationError::InvalidInput;
@@ -165,9 +161,7 @@ class JsonDeserializer {
     // Read each value
     for (;;) {
       // 1 - Skip value
-      _nestingLimit--;
-      DeserializationError err = skipVariant();
-      _nestingLimit++;
+      DeserializationError err = skipVariant(nestingLimit.decrement());
       if (err) return err;
 
       // 2 - Skip spaces
@@ -181,8 +175,9 @@ class JsonDeserializer {
   }
 
   template <typename TFilter>
-  DeserializationError parseObject(CollectionData &object, TFilter filter) {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
+  DeserializationError parseObject(CollectionData &object, TFilter filter,
+                                   NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
 
     // Check opening brace
     if (!eat('{')) return DeserializationError::InvalidInput;
@@ -221,15 +216,11 @@ class JsonDeserializer {
         }
 
         // Parse value
-        _nestingLimit--;
-        err = parseVariant(*variant, memberFilter);
-        _nestingLimit++;
+        err = parseVariant(*variant, memberFilter, nestingLimit.decrement());
         if (err) return err;
       } else {
         _stringStorage.reclaim(key);
-        _nestingLimit--;
-        err = skipVariant();
-        _nestingLimit++;
+        err = skipVariant(nestingLimit.decrement());
         if (err) return err;
       }
 
@@ -247,8 +238,8 @@ class JsonDeserializer {
     }
   }
 
-  DeserializationError skipObject() {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
+  DeserializationError skipObject(NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
 
     // Check opening brace
     if (!eat('{')) return DeserializationError::InvalidInput;
@@ -263,7 +254,7 @@ class JsonDeserializer {
     // Read each key value pair
     for (;;) {
       // Skip key
-      err = skipVariant();
+      err = skipVariant(nestingLimit.decrement());
       if (err) return err;
 
       // Skip spaces
@@ -272,9 +263,7 @@ class JsonDeserializer {
       if (!eat(':')) return DeserializationError::InvalidInput;
 
       // Skip value
-      _nestingLimit--;
-      err = skipVariant();
-      _nestingLimit++;
+      err = skipVariant(nestingLimit.decrement());
       if (err) return err;
 
       // Skip spaces
@@ -538,7 +527,6 @@ class JsonDeserializer {
 
   MemoryPool *_pool;
   TStringStorage _stringStorage;
-  uint8_t _nestingLimit;
   Latch<TReader> _latch;
 };
 
diff --git a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
index 47f895cf..aba92920 100644
--- a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
@@ -20,15 +20,16 @@ class MsgPackDeserializer {
 
  public:
   MsgPackDeserializer(MemoryPool &pool, TReader reader,
-                      TStringStorage stringStorage, uint8_t nestingLimit)
-      : _pool(&pool),
-        _reader(reader),
-        _stringStorage(stringStorage),
-        _nestingLimit(nestingLimit) {}
+                      TStringStorage stringStorage)
+      : _pool(&pool), _reader(reader), _stringStorage(stringStorage) {}
 
   // TODO: add support for filter
-  DeserializationError parse(VariantData &variant,
-                             AllowAllFilter = AllowAllFilter()) {
+  DeserializationError parse(VariantData &variant, AllowAllFilter,
+                             NestingLimit nestingLimit) {
+    return parse(variant, nestingLimit);
+  }
+
+  DeserializationError parse(VariantData &variant, NestingLimit nestingLimit) {
     uint8_t code;
     if (!readByte(code)) return DeserializationError::IncompleteInput;
 
@@ -48,11 +49,11 @@ class MsgPackDeserializer {
     }
 
     if ((code & 0xf0) == 0x90) {
-      return readArray(variant.toArray(), code & 0x0F);
+      return readArray(variant.toArray(), code & 0x0F, nestingLimit);
     }
 
     if ((code & 0xf0) == 0x80) {
-      return readObject(variant.toObject(), code & 0x0F);
+      return readObject(variant.toObject(), code & 0x0F, nestingLimit);
     }
 
     switch (code) {
@@ -116,16 +117,16 @@ class MsgPackDeserializer {
         return readString<uint32_t>(variant);
 
       case 0xdc:
-        return readArray<uint16_t>(variant.toArray());
+        return readArray<uint16_t>(variant.toArray(), nestingLimit);
 
       case 0xdd:
-        return readArray<uint32_t>(variant.toArray());
+        return readArray<uint32_t>(variant.toArray(), nestingLimit);
 
       case 0xde:
-        return readObject<uint16_t>(variant.toObject());
+        return readObject<uint16_t>(variant.toObject(), nestingLimit);
 
       case 0xdf:
-        return readObject<uint32_t>(variant.toObject());
+        return readObject<uint32_t>(variant.toObject(), nestingLimit);
 
       default:
         return DeserializationError::NotSupported;
@@ -242,36 +243,40 @@ class MsgPackDeserializer {
   }
 
   template <typename TSize>
-  DeserializationError readArray(CollectionData &array) {
+  DeserializationError readArray(CollectionData &array,
+                                 NestingLimit nestingLimit) {
     TSize size;
     if (!readInteger(size)) return DeserializationError::IncompleteInput;
-    return readArray(array, size);
+    return readArray(array, size, nestingLimit);
   }
 
-  DeserializationError readArray(CollectionData &array, size_t n) {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
-    --_nestingLimit;
+  DeserializationError readArray(CollectionData &array, size_t n,
+                                 NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
+
     for (; n; --n) {
       VariantData *value = array.add(_pool);
       if (!value) return DeserializationError::NoMemory;
 
-      DeserializationError err = parse(*value);
+      DeserializationError err = parse(*value, nestingLimit.decrement());
       if (err) return err;
     }
-    ++_nestingLimit;
+
     return DeserializationError::Ok;
   }
 
   template <typename TSize>
-  DeserializationError readObject(CollectionData &object) {
+  DeserializationError readObject(CollectionData &object,
+                                  NestingLimit nestingLimit) {
     TSize size;
     if (!readInteger(size)) return DeserializationError::IncompleteInput;
-    return readObject(object, size);
+    return readObject(object, size, nestingLimit);
   }
 
-  DeserializationError readObject(CollectionData &object, size_t n) {
-    if (_nestingLimit == 0) return DeserializationError::TooDeep;
-    --_nestingLimit;
+  DeserializationError readObject(CollectionData &object, size_t n,
+                                  NestingLimit nestingLimit) {
+    if (nestingLimit.reached()) return DeserializationError::TooDeep;
+
     for (; n; --n) {
       VariantSlot *slot = object.addSlot(_pool);
       if (!slot) return DeserializationError::NoMemory;
@@ -281,10 +286,10 @@ class MsgPackDeserializer {
       if (err) return err;
       slot->setOwnedKey(make_not_null(key));
 
-      err = parse(*slot->data());
+      err = parse(*slot->data(), nestingLimit.decrement());
       if (err) return err;
     }
-    ++_nestingLimit;
+
     return DeserializationError::Ok;
   }
 
@@ -312,7 +317,6 @@ class MsgPackDeserializer {
   MemoryPool *_pool;
   TReader _reader;
   TStringStorage _stringStorage;
-  uint8_t _nestingLimit;
 };
 
 template <typename TInput>