From c0af862562cc201eba7e31535833569b0fab4e3c Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Fri, 30 Apr 2021 23:41:18 +0000 Subject: [PATCH] Map enum tuple variants with no contents as unitary enum variants cbindgen maps `enum A { V() }` with a `struct A_V_Body {}` which has different size on C and C++ (0 and 1 bytes). While this is fine if a different variant has non-0 size as the union will be correctly sized. However, there isn't a lot of reason to rely on this when we can just have a unitary variant as well. --- c-bindings-gen/src/main.rs | 62 ++++++++++++++++++++++++++------------ 1 file changed, 43 insertions(+), 19 deletions(-) diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs index 81f26bf..c2ef30f 100644 --- a/c-bindings-gen/src/main.rs +++ b/c-bindings-gen/src/main.rs @@ -1159,16 +1159,26 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type } write!(w, "\t}}").unwrap(); } else if let syn::Fields::Unnamed(fields) = &var.fields { - needs_free = true; - write!(w, "(").unwrap(); - for (idx, field) in fields.unnamed.iter().enumerate() { - if export_status(&field.attrs) == ExportStatus::TestOnly { continue; } - types.write_c_type(w, &field.ty, Some(&gen_types), false); - if idx != fields.unnamed.len() - 1 { - write!(w, ",").unwrap(); + let mut empty_tuple_variant = false; + if fields.unnamed.len() == 1 { + let mut empty_check = Vec::new(); + types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false); + if empty_check.is_empty() { + empty_tuple_variant = true; + } + } + if !empty_tuple_variant { + needs_free = true; + write!(w, "(").unwrap(); + for (idx, field) in fields.unnamed.iter().enumerate() { + if export_status(&field.attrs) == ExportStatus::TestOnly { continue; } + types.write_c_type(w, &field.ty, Some(&gen_types), false); + if idx != fields.unnamed.len() - 1 { + write!(w, ",").unwrap(); + } } + write!(w, ")").unwrap(); } - write!(w, ")").unwrap(); } if var.discriminant.is_some() { unimplemented!(); } writeln!(w, ",").unwrap(); @@ -1180,6 +1190,7 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap(); for var in e.variants.iter() { write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap(); + let mut empty_tuple_variant = false; if let syn::Fields::Named(fields) = &var.fields { write!(w, "{{").unwrap(); for field in fields.named.iter() { @@ -1188,12 +1199,21 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type } write!(w, "}} ").unwrap(); } else if let syn::Fields::Unnamed(fields) = &var.fields { - write!(w, "(").unwrap(); - for (idx, field) in fields.unnamed.iter().enumerate() { - if export_status(&field.attrs) == ExportStatus::TestOnly { continue; } - write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap(); + if fields.unnamed.len() == 1 { + let mut empty_check = Vec::new(); + types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false); + if empty_check.is_empty() { + empty_tuple_variant = true; + } + } + if !empty_tuple_variant || $to_c { + write!(w, "(").unwrap(); + for (idx, field) in fields.unnamed.iter().enumerate() { + if export_status(&field.attrs) == ExportStatus::TestOnly { continue; } + write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap(); + } + write!(w, ") ").unwrap(); } - write!(w, ") ").unwrap(); } write!(w, "=>").unwrap(); @@ -1233,7 +1253,9 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type } else if let syn::Fields::Unnamed(fields) = &var.fields { write!(w, " {{\n\t\t\t\t").unwrap(); for (idx, field) in fields.unnamed.iter().enumerate() { - handle_field_a!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char)); + if !empty_tuple_variant { + handle_field_a!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char)); + } } } else { write!(w, " ").unwrap(); } @@ -1268,12 +1290,14 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type writeln!(w, "\n\t\t\t\t}}").unwrap(); write!(w, "\t\t\t}}").unwrap(); } else if let syn::Fields::Unnamed(fields) = &var.fields { - write!(w, " (").unwrap(); - for (idx, field) in fields.unnamed.iter().enumerate() { - write!(w, "\n\t\t\t\t\t").unwrap(); - handle_field_b!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char)); + if !empty_tuple_variant || !$to_c { + write!(w, " (").unwrap(); + for (idx, field) in fields.unnamed.iter().enumerate() { + write!(w, "\n\t\t\t\t\t").unwrap(); + handle_field_b!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char)); + } + writeln!(w, "\n\t\t\t\t)").unwrap(); } - writeln!(w, "\n\t\t\t\t)").unwrap(); write!(w, "\t\t\t}}").unwrap(); } writeln!(w, ",").unwrap(); -- 2.30.2