Add ArenaStlAllocator, and use arena throughout CommitRequest

src/commit_request.hpp

@@ -2,6 +2,7 @@
 
 #include "arena_allocator.hpp"
 #include <optional>
+#include <span>
 #include <stack>
 #include <string>
 #include <string_view>
@@ -61,10 +62,16 @@ public:
   };
 
   struct ParserContext {
-    std::stack<ParseState> state_stack;
-    std::string current_key;
-    std::string current_string;
-    std::string current_number;
+    using ArenaString = std::basic_string<char, std::char_traits<char>,
+                                          ArenaStlAllocator<char>>;
+    using ArenaStateStack =
+        std::stack<ParseState,
+                   std::vector<ParseState, ArenaStlAllocator<ParseState>>>;
+
+    ArenaStateStack state_stack;
+    ArenaString current_key;
+    ArenaString current_string;
+    ArenaString current_number;
     bool in_key = false;
     bool parse_error = false;
     bool parse_complete = false;
@@ -74,8 +81,18 @@ public:
     Operation current_operation{};
 
     // Parsing state for nested structures
-    std::string precondition_type;
-    std::string operation_type;
+    ArenaString precondition_type;
+    ArenaString operation_type;
+
+    // Constructor to initialize arena-allocated containers
+    explicit ParserContext(ArenaAllocator *arena)
+        : 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)) {}
   };
 
 private:
@@ -83,8 +100,8 @@ private:
   std::optional<std::string_view> request_id_;
   std::string_view leader_id_;
   uint64_t read_version_ = 0;
-  std::vector<Precondition> preconditions_;
-  std::vector<Operation> operations_;
+  std::vector<Precondition, ArenaStlAllocator<Precondition>> preconditions_;
+  std::vector<Operation, ArenaStlAllocator<Operation>> operations_;
   ParserContext parser_context_;
   WeaselJsonParser *json_parser_ = nullptr;
 
@@ -93,7 +110,11 @@ public:
    * @brief Construct a new CommitRequest with the given initial arena size.
    * @param arena_size Initial size for the arena allocator
    */
-  explicit CommitRequest(size_t arena_size = 4096) : arena_(arena_size) {}
+  explicit CommitRequest(size_t arena_size = 4096)
+      : arena_(arena_size),
+        preconditions_(ArenaStlAllocator<Precondition>(&arena_)),
+        operations_(ArenaStlAllocator<Operation>(&arena_)),
+        parser_context_(&arena_) {}
 
   /**
    * @brief Destructor - cleans up any active parser.
@@ -203,17 +224,15 @@ public:
 
   /**
    * @brief Get the preconditions.
-   * @return Vector of preconditions
+   * @return span of preconditions
    */
-  const std::vector<Precondition> &preconditions() const {
-    return preconditions_;
-  }
+  std::span<const Precondition> preconditions() const { return preconditions_; }
 
   /**
    * @brief Get the operations.
-   * @return Vector of operations
+   * @return span of operations
    */
-  const std::vector<Operation> &operations() const { return operations_; }
+  std::span<const Operation> operations() const { return operations_; }
 
   /**
    * @brief Get the total allocated bytes in the arena.
@@ -243,7 +262,7 @@ public:
       WeaselJsonParser_destroy(json_parser_);
       json_parser_ = nullptr;
     }
-    parser_context_ = ParserContext{};
+    parser_context_ = ParserContext(&arena_);
     parser_context_.state_stack.push(ParseState::Root);
   }