feat: support struct and pointer return types (#41)

Co-authored-by: Divy Srivastava <[email protected]>
denoland · Jan 10, 2022 · ccbd96e · ccbd96e
1 parent 2e91011
commit ccbd96e
Show file tree

Hide file tree

Showing 8 changed files with 312 additions and 116 deletions.
diff --git a/Makefile b/Makefile
@@ -3,4 +3,4 @@ fmt:
 	deno fmt --ignore=target/,example/target/,example/bindings/
 
 test:
-	cd example && deno_bindgen && deno test -A --unstable
+	cd example && deno run -A ../cli.ts && deno test -A --unstable
diff --git a/codegen.ts b/codegen.ts
@@ -42,6 +42,7 @@ const BufferTypes: Record<string, string> = {
   str: "string",
   buffer: "Uint8Array",
   buffermut: "Uint8Array",
+  ptr: "Uint8Array",
 };
 
 enum Encoder {
@@ -53,6 +54,7 @@ const BufferTypeEncoders: Record<keyof typeof BufferTypes, Encoder> = {
   str: Encoder.None,
   buffer: Encoder.None,
   buffermut: Encoder.None,
+  ptr: Encoder.None,
 };
 
 type TypeDef = Record<string, Record<string, string>>;
@@ -90,8 +92,12 @@ type Options = {
   release?: boolean;
 };
 
+function isTypeDef(p: any) {
+  return typeof p !== "string";
+}
+
 function isBufferType(p: any) {
-  return typeof p !== "string" || BufferTypes[p] !== undefined;
+  return isTypeDef(p) || BufferTypes[p] !== undefined;
 }
 
 // @littledivy is a dumb kid!
@@ -125,7 +131,10 @@ function encode(v: string | Uint8Array): Uint8Array {
   if (typeof v !== "string") return v;
   return new TextEncoder().encode(v);
 }
-function decode(v: any): Uint8Array {
+function decode(v: Uint8Array): string {
+  return new TextDecoder().decode(v);
+}
+function read_pointer(v: any): Uint8Array {
   const ptr = new Deno.UnsafePointerView(v as Deno.UnsafePointer)
   const lengthBe = new Uint8Array(4);
   const view = new DataView(lengthBe.buffer);
@@ -156,14 +165,14 @@ const _lib = await prepare(opts, {
     } });
 ${Object.keys(decl).map((def) => typescript[def]).join("\n")}
 ${
-      Object.keys(signature).map((sig) =>
-        `export function ${sig}(${
-          signature[sig].parameters.map((p, i) =>
-            `a${i}: ${resolveType(decl, p)}`
-          ).join(",")
+      Object.keys(signature).map((sig) => {
+        const { parameters, result, nonBlocking } = signature[sig];
+
+        return `export function ${sig}(${
+          parameters.map((p, i) => `a${i}: ${resolveType(decl, p)}`).join(",")
         }) {
   ${
-          signature[sig].parameters.map((p, i) =>
+          parameters.map((p, i) =>
             isBufferType(p)
               ? `const a${i}_buf = encode(${
                 BufferTypeEncoders[p] ?? Encoder.JsonStringify
@@ -172,18 +181,40 @@ ${
           ).filter((c) => c !== null).join("\n")
         }
   let result = _lib.symbols.${sig}(${
-          signature[sig].parameters.map((p, i) =>
+          parameters.map((p, i) =>
             isBufferType(p) ? `a${i}_buf, a${i}_buf.byteLength` : `a${i}`
           ).join(", ")
         }) as ${
-          signature[sig].nonBlocking
-            ? `Promise<${resolveType(decl, signature[sig].result)}>`
-            : resolveType(decl, signature[sig].result)
+          nonBlocking
+            ? `Promise<${
+              isTypeDef(result)
+                ? "Uint8Array"
+                : resolveType(decl, result)
+            }>`
+            : isTypeDef(result)
+            ? "Uint8Array"
+            : resolveType(decl, result)
         }
-  ${isBufferType(signature[sig].result) ? `result = decode(result);` : ""}
-  return result;
-}`
-      ).join("\n")
+  ${
+          isBufferType(result)
+            ? nonBlocking
+              ? `result = result.then(read_pointer)`
+              : `result = read_pointer(result)`
+            : ""
+        };
+  ${
+          isTypeDef(result)
+            ? nonBlocking
+              ? `return result.then(r => JSON.parse(decode(r))) as Promise<${
+                resolveType(decl, result)
+              }>`
+              : `return JSON.parse(decode(result)) as ${
+                resolveType(decl, result)
+              }`
+            : "return result"
+        };
+}`;
+      }).join("\n")
     }
  `,
   );

diff --git a/deno_bindgen_macro/src/derive_fn.rs b/deno_bindgen_macro/src/derive_fn.rs
@@ -88,6 +88,7 @@ pub fn process_function(
   let result = match &function.sig.output {
     ReturnType::Default => Type::Void,
     ReturnType::Type(_, ref ty) => match ty.as_ref() {
+      syn::Type::Ptr(_) => Type::Ptr,
       syn::Type::Path(ref ty) => {
         let segment = ty.path.segments.first().unwrap();
         let ident = segment.ident.to_string();
@@ -105,7 +106,12 @@ pub fn process_function(
           "isize" => Type::Isize,
           "f32" => Type::F32,
           "f64" => Type::F64,
-          _ => panic!("{} return type not supported by Deno FFI", ident),
+          _ => {
+            match metadata.type_defs.get(&ident) {
+              Some(_) => Type::StructEnum { ident },
+              None => panic!("{} return type not supported by Deno FFI", ident)
+            } 
+          }
         }
       }
       syn::Type::Reference(ref ty) => match *ty.elem {

diff --git a/deno_bindgen_macro/src/lib.rs b/deno_bindgen_macro/src/lib.rs
@@ -146,11 +146,30 @@ pub fn deno_bindgen(attr: TokenStream, input: TokenStream) -> TokenStream {
             let result = v.as_ptr();
             // Leak the result to JS land.
             ::std::mem::forget(v);
+            result
           };
 
           (ty, transformer)
         }
-        _ => (syn::Type::from(symbol.result), quote! {}),
+        Type::StructEnum { .. } => {
+          let ty = parse_quote! { *const u8 };
+          let transformer = quote! {
+            let json = deno_bindgen::serde_json::to_string(&result).expect("Failed to serialize as JSON");
+            let encoded = json.into_bytes();
+            let length = (encoded.len() as u32).to_be_bytes();
+            let mut v = length.to_vec();
+            v.extend(encoded.clone());
+
+            let ret = v.as_ptr();
+            // Leak the result to JS land.
+            ::std::mem::forget(v);
+            ret
+          };
+
+          (ty, transformer)
+        }, 
+        Type::Ptr => (parse_quote! { *const u8 }, quote! { result }),
+        _ => (syn::Type::from(symbol.result), quote! { result }),
       };
 
       let name = &func.sig.ident;
@@ -174,7 +193,6 @@ pub fn deno_bindgen(attr: TokenStream, input: TokenStream) -> TokenStream {
           #overrides
           let result = __inner_impl(#(#input_idents, ) *);
           #transformer
-          result
         }
       })
     }
@@ -187,7 +205,7 @@ pub fn deno_bindgen(attr: TokenStream, input: TokenStream) -> TokenStream {
         .unwrap();
 
       TokenStream::from(quote! {
-        #[derive(::serde::Deserialize)]
+        #[derive(::serde::Deserialize,::serde::Serialize)]
         #input
       })
     }

diff --git a/deno_bindgen_macro/src/meta.rs b/deno_bindgen_macro/src/meta.rs
@@ -27,6 +27,7 @@ pub enum Type {
   Buffer,
   BufferMut,
   Str,
+  Ptr,
 
   /// Not-so straightforward types that
   /// `deno_bingen` maps to.
-Original file line number
+Diff line change
@@ Expand Up / @@ -27,6 +27,7 @@ pub enum Type { @@
       Buffer,
       BufferMut,
       Str,
+      Ptr,
       /// Not-so straightforward types that
       /// `deno_bingen` maps to.
@@ Expand Down @@