erlang_h1

%% Copyright (c) 2026 Benoit Chesneau.
%% SPDX-License-Identifier: Apache-2.0
%%
%% h1.hrl - HTTP/1.1 library common definitions

-ifndef(H1_HRL).
-define(H1_HRL, 1).

%% ----------------------------------------------------------------------------
%% Default parser limits
%% ----------------------------------------------------------------------------
-define(H1_MAX_METHOD_SIZE,       16).
-define(H1_MAX_URI_SIZE,          8192).
-define(H1_MAX_HEADER_NAME_SIZE,  256).
-define(H1_MAX_HEADER_VALUE_SIZE, 8192).
-define(H1_MAX_HEADERS,           100).
-define(H1_MAX_CHUNK_SIZE,        1048576).   %% 1 MB
-define(H1_MAX_BODY_SIZE,         8388608).   %% 8 MB
-define(H1_MAX_LINE_LENGTH,       16384).     %% hackney default
-define(H1_MAX_HEADER_BLOCK_SIZE, 65536).     %% total header-block bytes (DoS guard)
-define(H1_MAX_EMPTY_LINES,       10).
-define(H1_MAX_CHUNK_SIZE_HEX,    16).         %% 64-bit max, way past any legit chunk
-define(H1_MAX_CHUNK_EXT_SIZE,    4096).       %% cap chunk-extension scan (DoS guard)

%% ----------------------------------------------------------------------------
%% HTTP versions
%% ----------------------------------------------------------------------------
-define(HTTP_1_0, {1, 0}).
-define(HTTP_1_1, {1, 1}).

%% ----------------------------------------------------------------------------
%% Parser state record
%%
%% Streaming dual-mode parser (server + client). Feed bytes via
%% h1_parse_erl:execute/2 and consume events one at a time.
%% ----------------------------------------------------------------------------
-record(h1_parser, {
    %% Mode
    type             = auto :: auto | request | response,
    %% Current phase
    state            = on_first_line :: on_first_line | on_header | on_body
                                      | on_trailers | on_junk | done,
    %% Unconsumed input
    buffer           = <<>> :: binary(),
    %% Parsed metadata
    version          = undefined :: undefined | {non_neg_integer(), non_neg_integer()},
    method           = undefined :: undefined | binary(),
    status           = undefined :: undefined | 100..599,
    partial_headers  = []        :: [{binary(), binary()}],
    %% Fast-path header values (lowercased where noted).
    %% `clen' transitions: undefined -> N  (first valid value)
    %%                      N         -> N          (duplicate same value)
    %%                      N         -> conflict   (differing value)
    %%                      _         -> bad_int    (unparsable)
    clen             = undefined :: undefined | non_neg_integer() | bad_int | conflict,
    te               = undefined :: undefined | binary(),   %% lowercased
    connection       = undefined :: undefined | binary(),   %% lowercased
    ctype            = undefined :: undefined | binary(),   %% lowercased
    upgrade          = undefined :: undefined | binary(),   %% lowercased
    expect           = undefined :: undefined | binary(),   %% lowercased
    %% Framing decision computed at end-of-headers.
    body_framing     = undefined :: undefined | no_body
                                  | {content_length, non_neg_integer()}
                                  | chunked | close_delimited,
    %% Body decoder state
    body_state       = waiting :: waiting | done
                                | {stream, fun(), term(), fun()},
    body_read        = 0 :: non_neg_integer(),
    %% Limits
    max_line_length  = ?H1_MAX_LINE_LENGTH   :: pos_integer(),
    max_empty_lines  = ?H1_MAX_EMPTY_LINES   :: non_neg_integer(),
    max_header_name_size  = ?H1_MAX_HEADER_NAME_SIZE  :: pos_integer(),
    max_header_value_size = ?H1_MAX_HEADER_VALUE_SIZE :: pos_integer(),
    max_headers      = ?H1_MAX_HEADERS       :: pos_integer(),
    max_body_size    = ?H1_MAX_BODY_SIZE     :: pos_integer() | infinity,
    max_header_block_size = ?H1_MAX_HEADER_BLOCK_SIZE :: pos_integer(),
    %% Counters
    empty_lines      = 0       :: non_neg_integer(),
    header_count     = 0       :: non_neg_integer(),
    %% Total bytes consumed in the current header (or trailer) block.
    header_bytes     = 0       :: non_neg_integer()
}).

-endif.