Merge pull request #3477 from wasmerio/js-custom-sections

Added support for Wasm Module custom sections in js

lib/api/src/js/module.rs

@@ -566,17 +566,14 @@ impl Module {
     /// custom sections. That's why an iterator (rather than one element)
     /// is returned.
     pub fn custom_sections<'a>(&'a self, name: &'a str) -> impl Iterator<Item = Box<[u8]>> + 'a {
-        // TODO: implement on JavaScript
-        DefaultCustomSectionsIterator {}
-    }
-}
-
-pub struct DefaultCustomSectionsIterator {}
-
-impl Iterator for DefaultCustomSectionsIterator {
-    type Item = Box<[u8]>;
-    fn next(&mut self) -> Option<Self::Item> {
-        None
+        WebAssembly::Module::custom_sections(&self.module, name)
+            .iter()
+            .map(move |(buf_val)| {
+                let typebuf: js_sys::Uint8Array = js_sys::Uint8Array::new(&buf_val);
+                typebuf.to_vec().into_boxed_slice()
+            })
+            .collect::<Vec<Box<[u8]>>>()
+            .into_iter()
     }
 }
 

lib/api/tests/module.rs

@@ -275,3 +275,18 @@ fn calling_host_functions_with_negative_values_works() -> Result<(), String> {
 
     Ok(())
 }
+
+#[universal_test]
+fn module_custom_sections() -> Result<(), String> {
+    let store = Store::default();
+    let custom_section_wasm_bytes = include_bytes!("simple-name-section.wasm");
+    let module = Module::new(&store, custom_section_wasm_bytes).map_err(|e| format!("{e:?}"))?;
+    let sections = module.custom_sections("name");
+    let sections_vec: Vec<Box<[u8]>> = sections.collect();
+    assert_eq!(sections_vec.len(), 1);
+    assert_eq!(
+        sections_vec[0],
+        vec![2, 2, 36, 105, 1, 0, 0, 0].into_boxed_slice()
+    );
+    Ok(())
+}

lib/compiler/src/translator/module.rs

@@ -99,11 +99,15 @@ pub fn translate_module<'data>(
                 data,
                 data_offset,
                 ..
-            } => parse_name_section(
-                NameSectionReader::new(data, data_offset)
-                    .map_err(from_binaryreadererror_wasmerror)?,
-                environ,
-            )?,
+            } => {
+                // We still add the custom section data, but also read it as name section reader
+                environ.custom_section("name", data)?;
+                parse_name_section(
+                    NameSectionReader::new(data, data_offset)
+                        .map_err(from_binaryreadererror_wasmerror)?,
+                    environ,
+                )?
+            }
 
             Payload::CustomSection { name, data, .. } => environ.custom_section(name, data)?,