Bug 1331092 - Part 2: Implement Async Generator except yield*.

Tag #1287

1 files changed, 78 insertions, 18 deletions

diff --git a/js/src/jsfun.cpp b/js/src/jsfun.cpp
index 65d44cba7..ce1ca33fe 100644
--- a/js/src/jsfun.cpp
+++ b/js/src/jsfun.cpp
@@ -41,6 +41,7 @@
 #include "js/CallNonGenericMethod.h"
 #include "js/Proxy.h"
 #include "vm/AsyncFunction.h"
+#include "vm/AsyncIteration.h"
 #include "vm/Debugger.h"
 #include "vm/GlobalObject.h"
 #include "vm/Interpreter.h"
@@ -312,6 +313,8 @@ CallerGetterImpl(JSContext* cx, const CallArgs& args)
         JSFunction* callerFun = &callerObj->as<JSFunction>();
         if (IsWrappedAsyncFunction(callerFun))
             callerFun = GetUnwrappedAsyncFunction(callerFun);
+        else if (IsWrappedAsyncGenerator(callerFun))
+            callerFun = GetUnwrappedAsyncGenerator(callerFun);
         MOZ_ASSERT(!callerFun->isBuiltin(), "non-builtin iterator returned a builtin?");
 
         if (callerFun->strict()) {
@@ -364,13 +367,15 @@ static const JSPropertySpec function_properties[] = {
 static bool
 ResolveInterpretedFunctionPrototype(JSContext* cx, HandleFunction fun, HandleId id)
 {
-    MOZ_ASSERT(fun->isInterpreted() || fun->isAsmJSNative());
+    bool isAsyncGenerator = IsWrappedAsyncGenerator(fun);
+
+    MOZ_ASSERT_IF(!isAsyncGenerator, fun->isInterpreted() || fun->isAsmJSNative());
     MOZ_ASSERT(id == NameToId(cx->names().prototype));
 
     // Assert that fun is not a compiler-created function object, which
     // must never leak to script or embedding code and then be mutated.
     // Also assert that fun is not bound, per the ES5 15.3.4.5 ref above.
-    MOZ_ASSERT(!IsInternalFunctionObject(*fun));
+    MOZ_ASSERT_IF(!isAsyncGenerator, !IsInternalFunctionObject(*fun));
     MOZ_ASSERT(!fun->isBoundFunction());
 
     // Make the prototype object an instance of Object with the same parent as
@@ -380,7 +385,9 @@ ResolveInterpretedFunctionPrototype(JSContext* cx, HandleFunction fun, HandleId
     bool isStarGenerator = fun->isStarGenerator();
     Rooted<GlobalObject*> global(cx, &fun->global());
     RootedObject objProto(cx);
-    if (isStarGenerator)
+    if (isAsyncGenerator)
+        objProto = GlobalObject::getOrCreateAsyncGeneratorPrototype(cx, global);
+    else if (isStarGenerator)
         objProto = GlobalObject::getOrCreateStarGeneratorObjectPrototype(cx, global);
     else
         objProto = GlobalObject::getOrCreateObjectPrototype(cx, global);
@@ -396,7 +403,7 @@ ResolveInterpretedFunctionPrototype(JSContext* cx, HandleFunction fun, HandleId
     // non-enumerable, and writable.  However, per the 15 July 2013 ES6 draft,
     // section 15.19.3, the .prototype of a generator function does not link
     // back with a .constructor.
-    if (!isStarGenerator) {
+    if (!isStarGenerator && !isAsyncGenerator) {
         RootedValue objVal(cx, ObjectValue(*fun));
         if (!DefineProperty(cx, proto, cx->names().constructor, objVal, nullptr, nullptr, 0))
             return false;
@@ -446,11 +453,13 @@ fun_resolve(JSContext* cx, HandleObject obj, HandleId id, bool* resolvedp)
          * - Arrow functions
          * - Function.prototype
          */
-        if (fun->isBuiltin())
-            return true;
-        if (!fun->isConstructor()) {
-            if (!fun->isStarGenerator() && !fun->isLegacyGenerator() && !fun->isAsync())
+        if (!IsWrappedAsyncGenerator(fun)) {
+            if (fun->isBuiltin())
                 return true;
+            if (!fun->isConstructor()) {
+                if (!fun->isStarGenerator() && !fun->isLegacyGenerator() && !fun->isAsync())
+                    return true;
+            }
         }
 
         if (!ResolveInterpretedFunctionPrototype(cx, fun, id))
@@ -946,6 +955,11 @@ js::FunctionToString(JSContext* cx, HandleFunction fun, bool prettyPrint)
         return FunctionToString(cx, unwrapped, prettyPrint);
     }
 
+    if (IsWrappedAsyncGenerator(fun)) {
+        RootedFunction unwrapped(cx, GetUnwrappedAsyncGenerator(fun));
+        return FunctionToString(cx, unwrapped, prettyPrint);
+    }
+
     StringBuffer out(cx);
     RootedScript script(cx);
 
@@ -1606,10 +1620,14 @@ FunctionConstructor(JSContext* cx, const CallArgs& args, GeneratorKind generator
                                          &mutedErrors);
 
     const char* introductionType = "Function";
-    if (isAsync)
-        introductionType = "AsyncFunction";
-    else if (generatorKind != NotGenerator)
+    if (isAsync) {
+        if (isStarGenerator)
+            introductionType = "AsyncGenerator";
+        else
+            introductionType = "AsyncFunction";
+    } else if (generatorKind != NotGenerator) {
         introductionType = "GeneratorFunction";
+    }
 
     const char* introducerFilename = filename;
     if (maybeScript && maybeScript->scriptSource()->introducerFilename())
@@ -1737,12 +1755,20 @@ FunctionConstructor(JSContext* cx, const CallArgs& args, GeneratorKind generator
                                               : SourceBufferHolder::NoOwnership;
     bool ok;
     SourceBufferHolder srcBuf(chars.begin().get(), chars.length(), ownership);
-    if (isAsync)
-        ok = frontend::CompileStandaloneAsyncFunction(cx, &fun, options, srcBuf, parameterListEnd);
-    else if (isStarGenerator)
-        ok = frontend::CompileStandaloneGenerator(cx, &fun, options, srcBuf, parameterListEnd);
-    else
-        ok = frontend::CompileStandaloneFunction(cx, &fun, options, srcBuf, parameterListEnd);
+    if (isAsync) {
+        if (isStarGenerator) {
+            ok = frontend::CompileStandaloneAsyncGenerator(cx, &fun, options, srcBuf,
+                                                           parameterListEnd);
+        } else {
+            ok = frontend::CompileStandaloneAsyncFunction(cx, &fun, options, srcBuf,
+                                                          parameterListEnd);
+        }
+    } else {
+        if (isStarGenerator)
+            ok = frontend::CompileStandaloneGenerator(cx, &fun, options, srcBuf, parameterListEnd);
+        else
+            ok = frontend::CompileStandaloneFunction(cx, &fun, options, srcBuf, parameterListEnd);
+    }
 
     // Step 33.
     args.rval().setObject(*fun);
@@ -1768,7 +1794,7 @@ js::AsyncFunctionConstructor(JSContext* cx, unsigned argc, Value* vp)
 {
     CallArgs args = CallArgsFromVp(argc, vp);
 
-    // Save the callee before its reset in FunctionConstructor().
+    // Save the callee before it's reset in FunctionConstructor().
     RootedObject newTarget(cx);
     if (args.isConstructing())
         newTarget = &args.newTarget().toObject();
@@ -1801,6 +1827,40 @@ js::AsyncFunctionConstructor(JSContext* cx, unsigned argc, Value* vp)
 }
 
 bool
+js::AsyncGeneratorConstructor(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    // Save the callee before its reset in FunctionConstructor().
+    RootedObject newTarget(cx);
+    if (args.isConstructing())
+        newTarget = &args.newTarget().toObject();
+    else
+        newTarget = &args.callee();
+
+    if (!FunctionConstructor(cx, args, StarGenerator, AsyncFunction))
+        return false;
+
+    RootedObject proto(cx);
+    if (!GetPrototypeFromConstructor(cx, newTarget, &proto))
+        return false;
+
+    if (!proto) {
+        proto = GlobalObject::getOrCreateAsyncGenerator(cx, cx->global());
+        if (!proto)
+            return false;
+    }
+
+    RootedFunction unwrapped(cx, &args.rval().toObject().as<JSFunction>());
+    RootedObject wrapped(cx, WrapAsyncGeneratorWithProto(cx, unwrapped, proto));
+    if (!wrapped)
+        return false;
+
+    args.rval().setObject(*wrapped);
+    return true;
+}
+
+bool
 JSFunction::isBuiltinFunctionConstructor()
 {
     return maybeNative() == Function || maybeNative() == Generator;