[bindings] Update eq/clone trait fns to take object, not this_arg

When a trait is required to implement eq/clone (eg in the case of
`SocketDescriptor`), the generated trait struct contains an
eq/clone function which takes a `this_arg` pointer. Since the trait
object can always be read to get the `this_arg` pointer, there is
no loss of generality to pass the trait object itself, and it
provides a bit more flexibility when the trait could be one of
several implementations (which we use in the Java higher-level
bindings).

diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index be3d36724853425184f0dc9fa78b5b91cde60850..4193f6d36206c14bc47c3aa733b23b355f5e529e 100644 (file)
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -226,7 +226,8 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                        generated_fields.push("clone".to_owned());
                },
                ("std::cmp::Eq", _) => {
-                       writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: *const c_void) -> bool,").unwrap();
+                       writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
+                       writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap();
                        generated_fields.push("eq".to_owned());
                },
                ("std::hash::Hash", _) => {
@@ -251,21 +252,25 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                ("std::cmp::Eq", _) => {
                        writeln!(w, "impl std::cmp::Eq for {} {{}}", trait_name).unwrap();
                        writeln!(w, "impl std::cmp::PartialEq for {} {{", trait_name).unwrap();
-                       writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o.this_arg) }}\n}}").unwrap();
+                       writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
                },
                ("std::hash::Hash", _) => {
                        writeln!(w, "impl std::hash::Hash for {} {{", trait_name).unwrap();
                        writeln!(w, "\tfn hash<H: std::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
                },
                ("Clone", _) => {
-                       writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
-                       writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
-                       writeln!(w, "\t\tSelf {{").unwrap();
-                       writeln!(w, "\t\tthis_arg: if let Some(f) = self.clone {{ (f)(self.this_arg) }} else {{ self.this_arg }},").unwrap();
+                       writeln!(w, "#[no_mangle]").unwrap();
+                       writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
+                       writeln!(w, "\t{} {{", trait_name).unwrap();
+                       writeln!(w, "\t\tthis_arg: if let Some(f) = orig.clone {{ (f)(orig.this_arg) }} else {{ orig.this_arg }},").unwrap();
                        for field in generated_fields.iter() {
-                               writeln!(w, "\t\t\t{}: self.{}.clone(),", field, field).unwrap();
+                               writeln!(w, "\t\t{}: orig.{}.clone(),", field, field).unwrap();
                        }
-                       writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
+                       writeln!(w, "\t}}\n}}").unwrap();
+                       writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
+                       writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
+                       writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
+                       writeln!(w, "\t}}\n}}").unwrap();
                },
                (s, i) => {
                        if s != "util::events::MessageSendEventsProvider" { unimplemented!(); }

diff --git a/lightning-c-bindings/demo.cpp b/lightning-c-bindings/demo.cpp
index 36a11a783a2e02add690b7c2c866b0aabe526942..84d7904f8e62e59e7e0ee156d326ec078a62f083 100644 (file)
--- a/lightning-c-bindings/demo.cpp
+++ b/lightning-c-bindings/demo.cpp
@@ -191,8 +191,8 @@ uintptr_t sock_send_data(void *this_arg, LDKu8slice data, bool resume_read) {
 void sock_disconnect_socket(void *this_arg) {
        close((int)((long)this_arg));
 }
-bool sock_eq(const void *this_arg, const void *other_arg) {
-       return this_arg == other_arg;
+bool sock_eq(const void *this_arg, const LDKSocketDescriptor *other_arg) {
+       return this_arg == other_arg->this_arg;
 }
 uint64_t sock_hash(const void *this_arg) {
        return (uint64_t)this_arg;