Merge pull request #138 from ospencer/oscar/js-buffer-size

Fix typed array canonical list lowering in JS bindgen

Author: alexcrichton

crates/gen-js/src/lib.rs

@@ -1734,7 +1734,7 @@ impl Bindgen for FunctionBindgen<'_> {
                         ));
                         // TODO: this is the wrong endianness
                         self.src.js(&format!(
-                            "(new Uint8Array(memory.buffer, ptr{}, len{0} * {})).set(new Uint8Array(val{0}.buffer));\n",
+                            "(new Uint8Array(memory.buffer, ptr{0}, len{0} * {1})).set(new Uint8Array(val{0}.buffer, val{0}.byteOffset, len{0} * {1}));\n",
                             tmp, size,
                         ));
                     }

tests/runtime/lists/exports.wit

@@ -9,4 +9,5 @@ list-result: function() -> list<u8>
 list-result2: function() -> string
 list-result3: function() -> list<string>
 
+list-roundtrip: function(a: list<u8>) -> list<u8>
 string-roundtrip: function(a: string) -> string

tests/runtime/lists/host.py

@@ -28,6 +28,9 @@ def list_result2(self) -> str:
     def list_result3(self) -> List[str]:
         return ['hello,', 'world!']
 
+    def list_roundtrip(self, a: bytes) -> bytes:
+        return a
+
     def string_roundtrip(self, a: str) -> str:
         return a
 

tests/runtime/lists/host.rs

@@ -43,6 +43,10 @@ impl Imports for MyImports {
         vec!["hello,".to_string(), "world!".to_string()]
     }
 
+    fn list_roundtrip(&mut self, list: &[u8]) -> Vec<u8> {
+        list.to_vec()
+    }
+
     fn string_roundtrip(&mut self, s: &str) -> String {
         s.to_string()
     }

tests/runtime/lists/host.ts

@@ -25,6 +25,7 @@ async function run() {
     },
     listResult2() { return 'hello!'; },
     listResult3() { return ['hello,', 'world!']; },
+    listRoundtrip(x) { return x; },
     stringRoundtrip(x) { return x; },
 
     unalignedRoundtrip1(u16, u32, u64, flag32, flag64) {
@@ -119,6 +120,12 @@ async function run() {
   assert.deepStrictEqual(Array.from(wasm.listResult()), [1, 2, 3, 4, 5]);
   assert.deepStrictEqual(wasm.listResult2(), "hello!");
   assert.deepStrictEqual(wasm.listResult3(), ["hello,", "world!"]);
+  
+  const buffer = new ArrayBuffer(8);
+  (new Uint8Array(buffer)).set(new Uint8Array([1, 2, 3, 4]), 2);
+  // Create a view of the four bytes in the middle of the buffer
+  const view = new Uint8Array(buffer, 2, 4);
+  assert.deepStrictEqual(Array.from(wasm.listRoundtrip(view)), [1, 2, 3, 4]);
 
   assert.deepStrictEqual(wasm.stringRoundtrip("x"), "x");
   assert.deepStrictEqual(wasm.stringRoundtrip(""), "");

tests/runtime/lists/imports.wit

@@ -30,6 +30,8 @@ list-minmax32: function(a: list<u32>, b: list<s32>) -> (list<u32>, list<s32>)
 list-minmax64: function(a: list<u64>, b: list<s64>) -> (list<u64>, list<s64>)
 list-minmax-float: function(a: list<f32>, b: list<f64>) -> (list<f32>, list<f64>)
 
+list-roundtrip: function(a: list<u8>) -> list<u8>
+
 string-roundtrip: function(a: string) -> string
 
 unaligned-roundtrip1: function(a: list<u16>, b: list<u32>, c: list<u64>, d: list<flag32>, e: list<flag64>)

tests/runtime/lists/wasm.c

@@ -283,6 +283,10 @@ void exports_list_result3(exports_list_string_t *ret0) {
   exports_string_dup(&ret0->ptr[1], "world!");
 }
 
+void exports_list_roundtrip(exports_list_u8_t *a, exports_list_u8_t *ret0) {
+  *ret0 = *a;
+}
+
 void exports_string_roundtrip(exports_string_t *a, exports_string_t *ret0) {
   *ret0 = *a;
 }

tests/runtime/lists/wasm.rs

@@ -159,6 +159,10 @@ impl exports::Exports for Exports {
         vec!["hello,".to_string(), "world!".to_string()]
     }
 
+    fn list_roundtrip(x: Vec<u8>) -> Vec<u8> {
+        x.clone()
+    }
+
     fn string_roundtrip(x: String) -> String {
         x.clone()
     }