Decouple parser from CommitRequest

src/json_commit_request_parser.hpp

@@ -0,0 +1,147 @@
+#pragma once
+
+#include "json_token_enum.hpp"
+#include "parser_interface.hpp"
+#include <memory>
+#include <simdutf.h>
+#include <weaseljson/weaseljson.h>
+
+/**
+ * @brief JSON-specific implementation of CommitRequestParser.
+ *
+ * This parser uses the weaseljson library to parse JSON-formatted
+ * commit requests into CommitRequest objects.
+ */
+class JsonCommitRequestParser : public CommitRequestParser {
+public:
+  // Parser state
+  enum class ParseState {
+    Root,
+    PreconditionsArray,
+    PreconditionObject,
+    OperationsArray,
+    OperationObject
+  };
+
+private:
+  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;
+  };
+
+  /**
+   * @brief Internal state for parsing an operation during JSON processing.
+   */
+  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;
+    std::optional<std::string_view> end;
+  };
+
+  struct ParserContext {
+    using ArenaString = std::basic_string<char, std::char_traits<char>,
+                                          ArenaStlAllocator<char>>;
+
+    ParseState current_state = ParseState::Root;
+    JsonTokenType current_key_token;
+    // Only used if we need to accumulate the current key
+    ArenaString current_key;
+    ArenaString current_string;
+    ArenaString current_number;
+    bool in_key = false;
+    const char *parse_error = nullptr;
+    bool parse_complete = false;
+
+    // Current objects being parsed
+    PreconditionParseState current_precondition{};
+    OperationParseState current_operation{};
+
+    // Parsing state for nested structures
+    ArenaString precondition_type;
+    ArenaString operation_type;
+
+    // Constructor to initialize arena-allocated containers
+    explicit ParserContext(ArenaAllocator *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(ArenaAllocator *arena) {
+      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)};
+      current_state = ParseState::Root;
+    }
+  };
+
+  WeaselJsonParser *json_parser_ = nullptr;
+  std::unique_ptr<ParserContext> parser_context_;
+  CommitRequest *current_request_ = nullptr;
+  static const WeaselJsonCallbacks json_callbacks;
+
+public:
+  /**
+   * @brief Construct a new JsonCommitRequestParser.
+   */
+  JsonCommitRequestParser();
+
+  /**
+   * @brief Destructor - cleans up any active parser.
+   */
+  ~JsonCommitRequestParser();
+
+  // Non-copyable but movable
+  JsonCommitRequestParser(const JsonCommitRequestParser &) = delete;
+  JsonCommitRequestParser &operator=(const JsonCommitRequestParser &) = delete;
+  JsonCommitRequestParser(JsonCommitRequestParser &&other) noexcept;
+  JsonCommitRequestParser &operator=(JsonCommitRequestParser &&other) noexcept;
+
+  // CommitRequestParser interface implementation
+  bool parse(CommitRequest &request, char *data, size_t len) override;
+  bool begin_streaming_parse(CommitRequest &request) override;
+  ParseStatus parse_chunk(CommitRequest &request, char *data,
+                          size_t len) override;
+  ParseStatus finish_streaming_parse(CommitRequest &request) override;
+  bool has_parse_error() const override;
+  const char *get_parse_error() const override;
+
+  // Weaseljson callbacks (public for global callbacks)
+  static void on_begin_object(void *userdata);
+  static void on_end_object(void *userdata);
+  static void on_string_data(void *userdata, const char *buf, int len,
+                             int done);
+  static void on_key_data(void *userdata, const char *buf, int len, int done);
+  static void on_begin_array(void *userdata);
+  static void on_end_array(void *userdata);
+  static void on_number_data(void *userdata, const char *buf, int len,
+                             int done);
+  static void on_true_literal(void *userdata);
+  static void on_false_literal(void *userdata);
+  static void on_null_literal(void *userdata);
+
+private:
+  /**
+   * @brief Decode a base64 string and store it in the arena.
+   * @param base64_str The base64 encoded string
+   * @return String view of decoded data, or empty view if decoding failed
+   */
+  std::string_view decode_base64(std::string_view base64_str);
+
+  void handle_completed_string(std::string_view s);
+  void handle_completed_number(std::string_view s);
+  void on_complete();
+};