Update LLHTTP and apply patch to support C++ interop (#3216)

### Motivation

C++ interop support in Xcode has started to dislike the header files
from llhttp. While a bug has been filed upstream at
nodejs/llparse#71 it doesn't seem as though
there is any movement on that fix upstream. As a result, we need to
apply a patch.

To keep the code maintainable, we'd like to apply that patch in an
automated fashion, so we should do so by amending the "update and patch"
script. Along the way, we should update LLHTTP to the latest code.

### Modifications

The modifications are split into separate commits.

1. Modify the script to fix some bugs that have crept in.
2. Run the script to update LLHTTP to latest, without the patch.
3. Fix up the tests to account for the fact that we get some different
errors from LLHTTP now.
4. Apply the patch suggested by @postmechanical in #3093
5. Re-run the script, which only applies the patch

### Result

C++ interop should be working again. Resolves #3093.

---------

Co-authored-by: George Barnett <gbarnett@apple.com>

Author: Lukasa

.licenseignore

@@ -32,7 +32,7 @@ Dockerfile
 **/Dockerfile
 Snippets/*
 Sources/CNIOAtomics/src/cpp_magic.h
-Sources/CNIOLLHTTP/LICENSE-MIT
+Sources/CNIOLLHTTP/LICENSE
 Sources/CNIOLLHTTP/c_nio_api.c
 Sources/CNIOLLHTTP/c_nio_http.c
 Sources/CNIOLLHTTP/c_nio_llhttp.c

Sources/CNIOLLHTTP/LICENSE-MIT renamed to Sources/CNIOLLHTTP/LICENSE

@@ -60,29 +60,14 @@ static int wasm_on_headers_complete_wrap(llhttp_t* p) {
 }
 
 const llhttp_settings_t wasm_settings = {
-  wasm_on_message_begin,
-  wasm_on_url,
-  wasm_on_status,
-  NULL,
-  NULL,
-  wasm_on_header_field,
-  wasm_on_header_value,
-  NULL,
-  NULL,
-  wasm_on_headers_complete_wrap,
-  wasm_on_body,
-  wasm_on_message_complete,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
+  .on_message_begin = wasm_on_message_begin,
+  .on_url = wasm_on_url,
+  .on_status = wasm_on_status,
+  .on_header_field = wasm_on_header_field,
+  .on_header_value = wasm_on_header_value,
+  .on_headers_complete = wasm_on_headers_complete_wrap,
+  .on_body = wasm_on_body,
+  .on_message_complete = wasm_on_message_complete,
 };
 
 
@@ -129,7 +114,7 @@ void c_nio_llhttp_reset(llhttp_t* parser) {
   llhttp_type_t type = parser->type;
   const llhttp_settings_t* settings = parser->settings;
   void* data = parser->data;
-  uint8_t lenient_flags = parser->lenient_flags;
+  uint16_t lenient_flags = parser->lenient_flags;
 
   c_nio_llhttp__internal_init(parser);
 
@@ -318,6 +303,22 @@ void c_nio_llhttp_set_lenient_optional_crlf_after_chunk(llhttp_t* parser, int en
   }
 }
 
+void c_nio_llhttp_set_lenient_optional_cr_before_lf(llhttp_t* parser, int enabled) {
+  if (enabled) {
+    parser->lenient_flags |= LENIENT_OPTIONAL_CR_BEFORE_LF;
+  } else {
+    parser->lenient_flags &= ~LENIENT_OPTIONAL_CR_BEFORE_LF;
+  }
+}
+
+void c_nio_llhttp_set_lenient_spaces_after_chunk_size(llhttp_t* parser, int enabled) {
+  if (enabled) {
+    parser->lenient_flags |= LENIENT_SPACES_AFTER_CHUNK_SIZE;
+  } else {
+    parser->lenient_flags &= ~LENIENT_SPACES_AFTER_CHUNK_SIZE;
+  }
+}
+
 /* Callbacks */
 
 
@@ -328,6 +329,20 @@ int c_nio_llhttp__on_message_begin(llhttp_t* s, const char* p, const char* endp)
 }
 
 
+int c_nio_llhttp__on_protocol(llhttp_t* s, const char* p, const char* endp) {
+  int err;
+  SPAN_CALLBACK_MAYBE(s, on_protocol, p, endp - p);
+  return err;
+}
+
+
+int c_nio_llhttp__on_protocol_complete(llhttp_t* s, const char* p, const char* endp) {
+  int err;
+  CALLBACK_MAYBE(s, on_protocol_complete);
+  return err;
+}
+
+
 int c_nio_llhttp__on_url(llhttp_t* s, const char* p, const char* endp) {
   int err;
   SPAN_CALLBACK_MAYBE(s, on_url, p, endp - p);

Sources/CNIOLLHTTP/c_nio_api.c

@@ -42,13 +42,33 @@ int c_nio_llhttp__after_headers_complete(llhttp_t* parser, const char* p,
   int hasBody;
 
   hasBody = parser->flags & F_CHUNKED || parser->content_length > 0;
-  if (parser->upgrade && (parser->method == HTTP_CONNECT ||
-                          (parser->flags & F_SKIPBODY) || !hasBody)) {
+  if (
+      (parser->upgrade && (parser->method == HTTP_CONNECT ||
+                          (parser->flags & F_SKIPBODY) || !hasBody)) ||
+      /* See RFC 2616 section 4.4 - 1xx e.g. Continue */
+      (parser->type == HTTP_RESPONSE && parser->status_code == 101)
+  ) {
     /* Exit, the rest of the message is in a different protocol. */
     return 1;
   }
 
-  if (parser->flags & F_SKIPBODY) {
+  if (parser->type == HTTP_RESPONSE && parser->status_code == 100) {
+    /* No body, restart as the message is complete */
+    return 0;
+  }
+
+  /* See RFC 2616 section 4.4 */
+  if (
+    parser->flags & F_SKIPBODY ||         /* response to a HEAD request */
+    (
+      parser->type == HTTP_RESPONSE && (
+        parser->status_code == 102 ||     /* Processing */
+        parser->status_code == 103 ||     /* Early Hints */
+        parser->status_code == 204 ||     /* No Content */
+        parser->status_code == 304        /* Not Modified */
+      )
+    )
+  ) {
     return 0;
   } else if (parser->flags & F_CHUNKED) {
     /* chunked encoding - ignore Content-Length header, prepare for a chunk */