Implements non-virtual destructor

README.md

@@ -4,14 +4,16 @@ This is a Rust crate to generate binding to C++ functions and methods with **zer
 
 The goal of this crate is to allows efficient integration between Rust and C++, which mean most of the generated code will be unsafe. You need to know how the C++ code you are going to use is working otherwise you will be hit by undefined behaviors.
 
+Only x86-64 Linux is supported at the moment. A PR to adds supports for other platforms is welcome!
+
 ## Requirements
 
 - C++11 and its toolchain.
 
 ## Limitations
 
 - Rust cannot access an instance variable directly. You need to create a getter/setter for each variable you want to access.
-- Inline method is not supported. That mean you cannot define a method you want to use inside a class declaration.
+- Inline method is not supported (including constructors and destructor that auto generated by C++ compiler). You need to create a method definition outside a class declaration.
 
 ## Usage
 

example/src/main.cpp

@@ -6,6 +6,7 @@ class class1 {
 public:
     class1();
     class1(const char *v1);
+    ~class1();
 protected:
     std::string v1;
 };
@@ -19,3 +20,7 @@ class1::class1()
 class1::class1(const char *v1) : v1(v1)
 {
 }
+
+class1::~class1()
+{
+}

example/src/main.rs

@@ -1,6 +1,7 @@
 use cppbind::cpp;
 
 fn main() {
+    // Construct class1 directly on Rust stack.
     let mut v1 = class1_memory::new();
     let v1 = unsafe { class1::new1(&mut v1) };
 }

macros/src/cpp.rs

@@ -63,7 +63,7 @@ fn render_class(item: Class) -> syn::Result<TokenStream> {
 
     for (i, ctor) in item.ctors.iter().enumerate() {
         let name = format_ident!("new{}", i + 1, span = ctor.span);
-        let ffi = format_ident!("{}_new{}", class, i + 1, span = Span::call_site());
+        let ffi = format_ident!("{}_ctor{}", class, i + 1, span = Span::call_site());
 
         impls.extend(quote! {
             pub unsafe fn #name(mut this: T) -> Self {
@@ -98,7 +98,7 @@ fn render_class(item: Class) -> syn::Result<TokenStream> {
         // Render.
         let sym = Symbol::new(name, Some(Signature::new(params)));
         let sym = sym.to_itanium();
-        let name = format_ident!("{}_new{}", class, i + 1, span = Span::call_site());
+        let name = format_ident!("{}_ctor{}", class, i + 1, span = Span::call_site());
 
         externs.extend(quote! {
             unsafe extern "C-unwind" {
@@ -108,6 +108,21 @@ fn render_class(item: Class) -> syn::Result<TokenStream> {
         });
     }
 
+    // Generate destructor FFI.
+    let dtor = format_ident!("{}_dtor", class, span = Span::call_site());
+    let sym = Symbol::new(
+        vec![Segment::Ident(name.as_str().into()), Segment::Dtor],
+        Some(Signature::new(vec![Type::Void])),
+    )
+    .to_itanium();
+
+    externs.extend(quote! {
+        unsafe extern "C-unwind" {
+            #[link_name = #sym]
+            fn #dtor(this: *mut (), __in_chrg: ::std::ffi::c_int);
+        }
+    });
+
     // Compose.
     let align = Literal::usize_unsuffixed(align);
     let mem = if name.chars().next().unwrap().is_uppercase() {
@@ -118,7 +133,7 @@ fn render_class(item: Class) -> syn::Result<TokenStream> {
 
     Ok(quote! {
         #[allow(non_camel_case_types)]
-        pub struct #class<T> {
+        pub struct #class<T: ::cppbind::Memory<Class = Self>> {
             mem: T,
             phantom: ::std::marker::PhantomData<::std::rc::Rc<()>>,
         }
@@ -127,6 +142,12 @@ fn render_class(item: Class) -> syn::Result<TokenStream> {
             #impls
         }
 
+        impl<T: ::cppbind::Memory<Class = Self>> Drop for #class<T> {
+            fn drop(&mut self) {
+                unsafe { #dtor(self.mem.as_mut_ptr(), 0) };
+            }
+        }
+
         #[allow(non_camel_case_types)]
         #[repr(C, align(#align))]
         pub struct #mem([::std::mem::MaybeUninit<u8>; #size]);

macros/src/symbol.rs

@@ -44,6 +44,7 @@ impl<'a> Symbol<'a> {
                 Segment::Ident(v) => write!(name, "{}{}", v.len(), v).unwrap(),
                 Segment::TemplateArg(_) => todo!(),
                 Segment::Ctor => name.push_str("C1"),
+                Segment::Dtor => name.push_str("D1"),
             }
         }
 
@@ -68,6 +69,7 @@ pub enum Segment<'a> {
     Ident(Cow<'a, str>),
     TemplateArg(TemplateArg<'a>),
     Ctor,
+    Dtor,
 }
 
 /// Argument of a template instantiation.