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Implement moving ownership of struct arguments to Rust

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This commit is contained in:
David Tolnay 2020-03-06 14:14:27 -08:00
parent 33169bdd59
commit f51447e2b9
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GPG Key ID: F9BA143B95FF6D82
1 changed files with 43 additions and 4 deletions
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47
gen/write.rs
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@ -19,7 +19,7 @@ pub(super) fn gen(namespace: Vec<String>, apis: &[Api], types: &Types, header: b
}
write_includes(out, types);
write_include_cxxbridge(out, types);
write_include_cxxbridge(out, apis, types);
out.next_section();
for name in &namespace {
@ -95,7 +95,7 @@ fn write_includes(out: &mut OutFile, types: &Types) {
}
}
fn write_include_cxxbridge(out: &mut OutFile, types: &Types) {
fn write_include_cxxbridge(out: &mut OutFile, apis: &[Api], types: &Types) {
let mut needs_rust_box = false;
for ty in types {
if let Type::RustBox(_) = ty {
@ -104,16 +104,47 @@ fn write_include_cxxbridge(out: &mut OutFile, types: &Types) {
}
}
let mut needs_manually_drop = false;
'outer: for api in apis {
if let Api::RustFunction(efn) = api {
for arg in &efn.args {
if arg.ty != RustString && types.needs_indirect_abi(&arg.ty) {
needs_manually_drop = true;
break 'outer;
}
}
}
}
out.begin_block("namespace rust");
out.begin_block("inline namespace cxxbridge01");
if needs_rust_box {
if needs_rust_box || needs_manually_drop {
writeln!(out, "// #include \"cxxbridge.h\"");
}
if needs_rust_box {
out.next_section();
for line in include::get("CXXBRIDGE01_RUST_BOX").lines() {
if !line.trim_start().starts_with("//") {
writeln!(out, "{}", line);
}
}
}
if needs_manually_drop {
out.next_section();
writeln!(out, "template <typename T>");
writeln!(out, "union ManuallyDrop {{");
writeln!(out, " T value;");
writeln!(
out,
" ManuallyDrop(T &&value) : value(::std::move(value)) {{}}",
);
writeln!(out, " ~ManuallyDrop() {{}}");
writeln!(out, "}};");
}
out.end_block("namespace cxxbridge01");
out.end_block("namespace rust");
}
@ -274,6 +305,13 @@ fn write_rust_function_shim(out: &mut OutFile, efn: &ExternFn, types: &Types) {
writeln!(out, ";");
} else {
writeln!(out, " {{");
for arg in &efn.args {
if arg.ty != RustString && types.needs_indirect_abi(&arg.ty) {
write!(out, " ::rust::ManuallyDrop<");
write_type(out, &arg.ty);
writeln!(out, "> {}$(::std::move({0}));", arg.ident);
}
}
write!(out, " ");
if indirect_return {
write!(out, "char return$[sizeof(");
@ -300,10 +338,11 @@ fn write_rust_function_shim(out: &mut OutFile, efn: &ExternFn, types: &Types) {
_ => {}
}
write!(out, "{}", arg.ident);
match arg.ty {
match &arg.ty {
Type::RustBox(_) => write!(out, ".into_raw()"),
Type::UniquePtr(_) => write!(out, ".release()"),
Type::Str(_) => write!(out, ")"),
ty if ty != RustString && types.needs_indirect_abi(ty) => write!(out, "$.value"),
_ => {}
}
}