1 files changed, 53 insertions, 0 deletions
diff --git a/js/src/rust/wasm.rs b/js/src/rust/wasm.rs
new file mode 100644
index 0000000000..73c7057b66
--- /dev/null
+++ b/js/src/rust/wasm.rs
@@ -0,0 +1,53 @@
+/* Copyright 2020 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#[no_mangle]
+pub unsafe extern "C" fn wasm_text_to_binary(
+    text: *const u16,
+    text_len: usize,
+    out_bytes: *mut *mut u8,
+    out_bytes_len: *mut usize,
+    out_error: *mut *mut u8,
+    out_error_len: *mut usize,
+) -> bool {
+    let text_slice = std::slice::from_raw_parts(text, text_len);
+    let text = String::from_utf16_lossy(text_slice);
+
+    match text_to_binary(&text) {
+        Ok(bytes) => {
+            let bytes_box = bytes.into_boxed_slice();
+            let bytes_slice = Box::leak(bytes_box);
+            out_bytes.write(bytes_slice.as_mut_ptr());
+            out_bytes_len.write(bytes_slice.len());
+            true
+        }
+        Err(error) => {
+            let error = Box::leak(format!("{}\0", error).into_boxed_str());
+            out_error.write(error.as_mut_ptr());
+            out_error_len.write(error.len());
+            false
+        }
+    }
+}
+
+fn text_to_binary(text: &str) -> Result<Vec<u8>, wast::Error> {
+    let mut lexer = wast::lexer::Lexer::new(text);
+    // The 'names.wast' spec test has confusable unicode, so disable detection.
+    // This protection is not very useful for a shell testing function anyways.
+    lexer.allow_confusing_unicode(true);
+    let buf = wast::parser::ParseBuffer::new_with_lexer(lexer)?;
+    let mut ast = wast::parser::parse::<wast::Wat>(&buf)?;
+    return ast.encode();
+}