sse_parser.h

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#pragma once
 
#include <neograph/api.h>
 
#include <cstddef>
#include <cstdint>
#include <optional>
#include <string>
#include <string_view>
#include <vector>
 
namespace neograph::async {
 
struct SseEvent {
    std::string event;   
    std::string data;    
    std::string id;      
};
 
struct SseParserOptions {
    std::size_t max_partial_line_bytes = 64u * 1024u;
    std::size_t max_event_bytes        = 1u * 1024u * 1024u;
    std::size_t max_pending_events     = 1024u;
    std::size_t max_pending_bytes      = 8u * 1024u * 1024u;
};
 
class NEOGRAPH_API SseEventParser {
public:
    explicit SseEventParser(SseParserOptions options = {});
 
    void feed(std::string_view bytes);
 
    std::vector<SseEvent> drain();
 
    const std::string& last_event_id() const noexcept { return last_id_; }
 
    std::optional<std::uint64_t> retry_ms() const noexcept { return retry_ms_; }
 
    void reset() noexcept;
 
private:
    void   consume_line(std::string_view line);
    void   finish_event();
    void   ensure_can_add(std::size_t current, std::size_t addition,
                          std::size_t limit, const char* message);
    [[noreturn]] void fail_limit(const char* message);
 
    SseParserOptions             options_;
    std::string                  raw_;              
    std::string                  cur_data_;         
    std::string                  cur_event_;        
    std::string                  last_id_;          
    std::optional<std::uint64_t> retry_ms_;
    std::size_t                  cur_event_bytes_ = 0;
    bool                         cur_has_data_ = false;
    bool                         skip_lf_ = false;  
    bool                         at_start_ = true;  
    std::vector<SseEvent>        pending_;
    std::size_t                  pending_bytes_ = 0;
    bool                         failed_ = false;
};
 
}  // namespace neograph::async