Expose objects and functions from the JavaScript global scope

Cargo.toml

@@ -17,7 +17,8 @@ test = false
 doctest = false
 
 [features]
-default = ["spans", "std"]
+default = ["spans", "std", "js_globals"]
+js_globals = []
 spans = ["wasm-bindgen-macro/spans"]
 std = []
 serde-serialize = ["serde", "serde_json", "std"]

crates/backend/src/codegen.rs

@@ -266,6 +266,7 @@ impl ToTokens for ast::StructField {
             }
 
             #[no_mangle]
+            #[doc(hidden)]
             pub extern fn #desc() {
                 use wasm_bindgen::describe::*;
                 <#ty as WasmDescribe>::describe();
@@ -445,6 +446,7 @@ impl ToTokens for ast::Export {
             // binary along with anything it references.
             #[no_mangle]
             #[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
+            #[doc(hidden)]
             pub extern fn #descriptor_name() {
                 use wasm_bindgen::describe::*;
                 inform(FUNCTION);
@@ -726,6 +728,7 @@ impl<'a> ToTokens for DescribeImport<'a> {
         (quote! {
             #[no_mangle]
             #[allow(non_snake_case)]
+            #[doc(hidden)]
             pub extern fn #describe_name() {
                 use wasm_bindgen::describe::*;
                 inform(FUNCTION);

crates/cli-support/src/js/mod.rs

@@ -29,7 +29,7 @@ pub struct Context<'a> {
     pub imported_names: HashSet<String>,
     pub exported_classes: HashMap<String, ExportedClass>,
     pub function_table_needed: bool,
-    pub run_descriptor: &'a Fn(&str) -> Vec<u32>,
+    pub run_descriptor: &'a Fn(&str) -> Option<Vec<u32>>,
     pub module_versions: Vec<(String, String)>,
 }
 
@@ -474,7 +474,10 @@ impl<'a> Context<'a> {
         for field in class.fields.iter() {
             let wasm_getter = shared::struct_field_get(name, &field.name);
             let wasm_setter = shared::struct_field_set(name, &field.name);
-            let descriptor = self.describe(&wasm_getter);
+            let descriptor = match self.describe(&wasm_getter) {
+                None => continue,
+                Some(d) => d,
+            };
 
             let set = {
                 let mut cx = Js2Rust::new(&field.name, self);
@@ -1393,10 +1396,9 @@ impl<'a> Context<'a> {
         Ok(())
     }
 
-    fn describe(&self, name: &str) -> Descriptor {
+    fn describe(&self, name: &str) -> Option<Descriptor> {
         let name = format!("__wbindgen_describe_{}", name);
-        let ret = (self.run_descriptor)(&name);
-        Descriptor::decode(&ret)
+        (self.run_descriptor)(&name).map(|d| Descriptor::decode(&d))
     }
 
     fn global(&mut self, s: &str) {
@@ -1474,7 +1476,12 @@ impl<'a, 'b> SubContext<'a, 'b> {
         if let Some(ref class) = export.class {
             return self.generate_export_for_class(class, export);
         }
-        let descriptor = self.cx.describe(&export.function.name);
+
+        let descriptor = match self.cx.describe(&export.function.name) {
+            None => return Ok(()),
+            Some(d) => d,
+        };
+
         let (js, ts) = Js2Rust::new(&export.function.name, self.cx)
             .process(descriptor.unwrap_function())?
             .finish("function", &format!("wasm.{}", export.function.name));
@@ -1492,7 +1499,12 @@ impl<'a, 'b> SubContext<'a, 'b> {
         export: &shared::Export,
     ) -> Result<(), Error> {
         let wasm_name = shared::struct_function_export_name(class_name, &export.function.name);
-        let descriptor = self.cx.describe(&wasm_name);
+
+        let descriptor = match self.cx.describe(&wasm_name) {
+            None => return Ok(()),
+            Some(d) => d,
+        };
+
         let (js, ts) = Js2Rust::new(&export.function.name, self.cx)
             .method(export.method)
             .process(descriptor.unwrap_function())?
@@ -1603,7 +1615,10 @@ impl<'a, 'b> SubContext<'a, 'b> {
                                 import: &shared::ImportFunction)
         -> Result<(), Error>
     {
-        let descriptor = self.cx.describe(&import.shim);
+        let descriptor = match self.cx.describe(&import.shim) {
+            None => return Ok(()),
+            Some(d) => d,
+        };
 
         let target = match import.class {
             Some(ref class) if import.js_new => {

crates/cli-support/src/lib.rs

@@ -140,11 +140,19 @@ impl Bindgen {
                 module_versions: Default::default(),
                 run_descriptor: &|name| {
                     let mut v = MyExternals(Vec::new());
-                    let ret = instance
-                        .invoke_export(name, &[], &mut v)
-                        .expect("failed to run export");
-                    assert!(ret.is_none());
-                    v.0
+                    match instance.invoke_export(name, &[], &mut v) {
+                        Ok(None) => Some(v.0),
+                        Ok(Some(_)) => {
+                            unreachable!(
+                                "there is only one export, and we only return None from it"
+                            )
+                        },
+                        // Allow missing exported describe functions. This can
+                        // happen when a nested dependency crate exports things
+                        // but the root crate doesn't use them.
+                        Err(wasmi::Error::Function(_)) => None,
+                        Err(e) => panic!("unexpected error running descriptor: {}", e),
+                    }
                 },
             };
             for program in programs.iter() {
@@ -342,6 +350,7 @@ impl wasmi::ImportResolver for MyResolver {
 }
 
 struct MyExternals(Vec<u32>);
+
 #[derive(Debug)]
 struct MyError(String);
 

crates/webidl/tests/expected/Event.rs

@@ -55,6 +55,7 @@ impl From<Event> for ::wasm_bindgen::JsValue {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_new_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -104,6 +105,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_event_phase_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -147,6 +149,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_stop_propagation_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -186,6 +189,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_stop_immediate_propagation_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -225,6 +229,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_bubbles_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -268,6 +273,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_cancelable_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -311,6 +317,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_prevent_default_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -350,6 +357,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_default_prevented_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -393,6 +401,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_default_prevented_by_chrome_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -436,6 +445,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_default_prevented_by_content_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -479,6 +489,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_composed_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -522,6 +533,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_is_trusted_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -565,6 +577,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_time_stamp_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -608,6 +621,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_init_event_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -661,6 +675,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_cancel_bubble_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -704,6 +719,7 @@ impl Event {
 }
 #[no_mangle]
 #[allow(non_snake_case)]
+#[doc(hidden)]
 pub extern "C" fn __wbindgen_describe___widl_f_set_cancel_bubble_Event() {
     use wasm_bindgen::describe::*;
     inform(FUNCTION);
@@ -753,4 +769,4 @@ pub type DOMHighResTimeStamp = f64;
 pub type EventInit = bool;
 #[allow(non_upper_case_globals)]
 #[wasm_custom_section = "__wasm_bindgen_unstable"]
-const __WASM_BINDGEN_GENERATED_wasm_bindgen_webidl_0_2_11_0 : [ u8 ; 4451usize ] = * b"_\x11\0\0{\"exports\":[],\"enums\":[],\"imports\":[{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"type\"}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_new_Event\",\"catch\":false,\"method\":false,\"js_new\":true,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"new\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_event_phase_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"eventPhase\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"eventPhase\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_stop_propagation_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"stopPropagation\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_stop_immediate_propagation_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"stopImmediatePropagation\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_bubbles_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"bubbles\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"bubbles\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_cancelable_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"cancelable\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"cancelable\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_prevent_default_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"preventDefault\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPrevented\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPrevented\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_by_chrome_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPreventedByChrome\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPreventedByChrome\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_by_content_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPreventedByContent\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPreventedByContent\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_composed_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"composed\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"composed\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_is_trusted_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"isTrusted\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"isTrusted\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_time_stamp_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"timeStamp\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"timeStamp\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_init_event_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"initEvent\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_cancel_bubble_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"cancelBubble\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"cancelBubble\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_set_cancel_bubble_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":\"cancelBubble\",\"class\":\"Event\",\"function\":{\"name\":\"set_CancelBubble\"}}}],\"structs\":[],\"version\":\"0.2.11 (0cd767c9d)\",\"schema_version\":\"4\"}" ;
+const __WASM_BINDGEN_GENERATED_wasm_bindgen_webidl_0_2_11_0 : [ u8 ; 4451usize ] = * b"_\x11\0\0{\"exports\":[],\"enums\":[],\"imports\":[{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"type\"}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_new_Event\",\"catch\":false,\"method\":false,\"js_new\":true,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"new\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_event_phase_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"eventPhase\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"eventPhase\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_stop_propagation_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"stopPropagation\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_stop_immediate_propagation_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"stopImmediatePropagation\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_bubbles_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"bubbles\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"bubbles\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_cancelable_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"cancelable\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"cancelable\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_prevent_default_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"preventDefault\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPrevented\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPrevented\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_by_chrome_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPreventedByChrome\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPreventedByChrome\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_default_prevented_by_content_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"defaultPreventedByContent\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"defaultPreventedByContent\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_composed_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"composed\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"composed\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_is_trusted_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"isTrusted\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"isTrusted\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_time_stamp_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"timeStamp\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"timeStamp\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_init_event_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"initEvent\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_cancel_bubble_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":\"cancelBubble\",\"setter\":null,\"class\":\"Event\",\"function\":{\"name\":\"cancelBubble\"}}},{\"module\":null,\"version\":null,\"js_namespace\":null,\"kind\":{\"kind\":\"function\",\"shim\":\"__widl_f_set_cancel_bubble_Event\",\"catch\":false,\"method\":true,\"js_new\":false,\"structural\":false,\"getter\":null,\"setter\":\"cancelBubble\",\"class\":\"Event\",\"function\":{\"name\":\"set_CancelBubble\"}}}],\"structs\":[],\"version\":\"0.2.11 (161fce9d5)\",\"schema_version\":\"4\"}" ;