Add a dummy padding argument to work around a Rust bug.

rust-lang/rust#25594

Author: SimonSapin

html5ever/__init__.py

@@ -139,8 +139,8 @@ def create_comment(parser, data):
     return parser._keep_alive(Comment(str_from_slice(data)))
 
 
-@ffi.callback('int(ParserUserData*, Utf8Slice, Utf8Slice, Utf8Slice)', error=-1)
-def append_doctype_to_document(parser, name, public_id, system_id):
+@ffi.callback('int(ParserUserData*, uintptr_t, Utf8Slice, Utf8Slice, Utf8Slice)', error=-1)
+def append_doctype_to_document(parser, _dummy, name, public_id, system_id):
     parser = ffi.from_handle(ffi.cast('void*', parser))
     parser.document.children.append(Doctype(
         str_from_slice(name),

html5ever/_build_ffi.py

@@ -28,7 +28,7 @@
         Node* (*get_template_contents)(ParserUserData*, Node*),
         int (*add_attribute_if_missing)(ParserUserData*, Node*, Utf8Slice, Utf8Slice, Utf8Slice),
         Node* (*create_comment)(ParserUserData*, Utf8Slice),
-        int (*append_doctype_to_document)(ParserUserData*, Utf8Slice, Utf8Slice, Utf8Slice),
+        int (*append_doctype_to_document)(ParserUserData*, uintptr_t, Utf8Slice, Utf8Slice, Utf8Slice),
 
         int (*append_node)(ParserUserData*, Node*, Node*),
         int (*append_text)(ParserUserData*, Node*, Utf8Slice),

rust-glue/lib.rs

@@ -16,7 +16,7 @@ use tendril::StrTendril;
 
 /// When given as a function parameter, only valid for the duration of the call.
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 #[allow(raw_pointer_derive)]
 pub struct BytesSlice {
     ptr: *const u8,
@@ -38,7 +38,7 @@ impl BytesSlice {
 
 /// When given as a function parameter, only valid for the duration of the call.
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct Utf8Slice(BytesSlice);
 
 impl Utf8Slice {
@@ -207,6 +207,7 @@ impl TreeSink for CallbackTreeSink {
                                   public_id: StrTendril,
                                   system_id: StrTendril) {
         check_int(call!(self, append_doctype_to_document(
+            0,
             Utf8Slice::from_str(&name),
             Utf8Slice::from_str(&public_id),
             Utf8Slice::from_str(&system_id))));
@@ -319,6 +320,9 @@ declare_with_callbacks! {
 
     /// Create a doctype node and append it to the document.
     callback append_doctype_to_document: extern "C" fn(*const OpaqueParserUserData,
+        // Work around https://github.com/rust-lang/rust/pull/27017
+        // Add some padding so that the last Utf8Slice is not split between registers and the stack.
+        usize,
         Utf8Slice, Utf8Slice, Utf8Slice) -> c_int
 
     callback append_node: extern "C" fn(*const OpaqueParserUserData,