Separate arena for state during parsing

src/commit_request.cpp

@@ -495,23 +495,28 @@ CommitRequest::ParseStatus CommitRequest::parse_chunk(char *data, size_t len) {
 }
 
 CommitRequest::ParseStatus CommitRequest::finish_streaming_parse() {
+
+  CommitRequest::ParseStatus result;
   if (!json_parser_) {
-    return ParseStatus::Error;
-  }
-
-  if (parser_context_.parse_error) {
-    return ParseStatus::Error;
-  }
-
-  // Signal end of input
-  WeaselJsonStatus status = WeaselJsonParser_parse(json_parser_, nullptr, 0);
-
-  if (status == WeaselJson_OK && parser_context_.parse_complete &&
-      !parser_context_.parse_error) {
-    return ParseStatus::Complete;
+    result = ParseStatus::Error;
+  } else if (parser_context_.parse_error) {
+    result = ParseStatus::Error;
   } else {
-    parser_context_.parse_error =
-        "JSON parsing incomplete or failed during finalization";
-    return ParseStatus::Error;
+
+    // Signal end of input
+    WeaselJsonStatus status = WeaselJsonParser_parse(json_parser_, nullptr, 0);
+
+    if (status == WeaselJson_OK && parser_context_.parse_complete &&
+        !parser_context_.parse_error) {
+      result = ParseStatus::Complete;
+    } else {
+      parser_context_.parse_error =
+          "JSON parsing incomplete or failed during finalization";
+      result = ParseStatus::Error;
+    }
   }
+  // Clear the memory used only during parsing
+  parser_context_.reset_arena_memory();
+
+  return result;
 }

src/commit_request.hpp

@@ -42,6 +42,7 @@ class CommitRequest {
   struct PreconditionParseState {
     Precondition::Type type;
     std::optional<uint64_t> version;
+    // These are owned by CommitRequest::arena
     std::optional<std::string_view> key;
     std::optional<std::string_view> begin;
     std::optional<std::string_view> end;
@@ -52,6 +53,7 @@ class CommitRequest {
    */
   struct OperationParseState {
     Operation::Type type;
+    // These are owned by CommitRequest::arena
     std::optional<std::string_view> key;
     std::optional<std::string_view> value;
     std::optional<std::string_view> begin;
@@ -83,6 +85,7 @@ public:
     using ArenaStateStack =
         std::stack<ParseState,
                    std::vector<ParseState, ArenaStlAllocator<ParseState>>>;
+    ArenaAllocator arena;
 
     ArenaStateStack state_stack;
     ArenaString current_key;
@@ -101,14 +104,27 @@ public:
     ArenaString operation_type;
 
     // Constructor to initialize arena-allocated containers
-    explicit ParserContext(ArenaAllocator *arena)
+    explicit ParserContext()
         : state_stack(ArenaStateStack::container_type(
-              ArenaStlAllocator<ParseState>(arena))),
-          current_key(ArenaStlAllocator<char>(arena)),
-          current_string(ArenaStlAllocator<char>(arena)),
-          current_number(ArenaStlAllocator<char>(arena)),
-          precondition_type(ArenaStlAllocator<char>(arena)),
-          operation_type(ArenaStlAllocator<char>(arena)) {}
+              ArenaStlAllocator<ParseState>(&arena))),
+          current_key(ArenaStlAllocator<char>(&arena)),
+          current_string(ArenaStlAllocator<char>(&arena)),
+          current_number(ArenaStlAllocator<char>(&arena)),
+          precondition_type(ArenaStlAllocator<char>(&arena)),
+          operation_type(ArenaStlAllocator<char>(&arena)) {}
+    void reset_arena_memory() {
+      arena.reset();
+      current_key = ArenaString{ArenaStlAllocator<char>(&arena)};
+      current_string = ArenaString{ArenaStlAllocator<char>(&arena)};
+      current_number = ArenaString{ArenaStlAllocator<char>(&arena)};
+      in_key = false;
+      current_precondition = {};
+      current_operation = {};
+      precondition_type = ArenaString{ArenaStlAllocator<char>(&arena)};
+      operation_type = ArenaString{ArenaStlAllocator<char>(&arena)};
+      state_stack = ArenaStateStack{ArenaStateStack::container_type(
+          ArenaStlAllocator<ParseState>(&arena))};
+    }
   };
 
 private:
@@ -131,8 +147,7 @@ public:
    */
   explicit CommitRequest()
       : arena_(), preconditions_(ArenaStlAllocator<Precondition>(&arena_)),
-        operations_(ArenaStlAllocator<Operation>(&arena_)),
-        parser_context_(&arena_) {}
+        operations_(ArenaStlAllocator<Operation>(&arena_)), parser_context_() {}
 
   /**
    * @brief Destructor - cleans up any active parser.
@@ -297,8 +312,10 @@ public:
     if (json_parser_) {
       WeaselJsonParser_reset(json_parser_);
     }
-    parser_context_ = ParserContext(&arena_);
+    parser_context_.reset_arena_memory();
     parser_context_.state_stack.push(ParseState::Root);
+    parser_context_.parse_error = nullptr;
+    parser_context_.parse_complete = false;
   }
 
   // Weaseljson callbacks (public for global callbacks)