1 files changed, 114 insertions, 0 deletions
diff --git a/js/src/builtin/Generator.js b/js/src/builtin/Generator.js
new file mode 100644
index 0000000000..ada80e3006
--- /dev/null
+++ b/js/src/builtin/Generator.js
@@ -0,0 +1,114 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function GeneratorNext(val) {
+  // The IsSuspendedGenerator call below is not necessary for correctness.
+  // It's a performance optimization to check for the common case with a
+  // single call. It's also inlined in Baseline.
+
+  if (!IsSuspendedGenerator(this)) {
+    if (!IsObject(this) || !IsGeneratorObject(this)) {
+      return callFunction(
+        CallGeneratorMethodIfWrapped,
+        this,
+        val,
+        "GeneratorNext"
+      );
+    }
+
+    if (GeneratorObjectIsClosed(this)) {
+      return { value: undefined, done: true };
+    }
+
+    if (GeneratorIsRunning(this)) {
+      ThrowTypeError(JSMSG_NESTING_GENERATOR);
+    }
+  }
+
+  try {
+    return resumeGenerator(this, val, "next");
+  } catch (e) {
+    if (!GeneratorObjectIsClosed(this)) {
+      GeneratorSetClosed(this);
+    }
+    throw e;
+  }
+}
+
+function GeneratorThrow(val) {
+  if (!IsSuspendedGenerator(this)) {
+    if (!IsObject(this) || !IsGeneratorObject(this)) {
+      return callFunction(
+        CallGeneratorMethodIfWrapped,
+        this,
+        val,
+        "GeneratorThrow"
+      );
+    }
+
+    if (GeneratorObjectIsClosed(this)) {
+      throw val;
+    }
+
+    if (GeneratorIsRunning(this)) {
+      ThrowTypeError(JSMSG_NESTING_GENERATOR);
+    }
+  }
+
+  try {
+    return resumeGenerator(this, val, "throw");
+  } catch (e) {
+    if (!GeneratorObjectIsClosed(this)) {
+      GeneratorSetClosed(this);
+    }
+    throw e;
+  }
+}
+
+function GeneratorReturn(val) {
+  if (!IsSuspendedGenerator(this)) {
+    if (!IsObject(this) || !IsGeneratorObject(this)) {
+      return callFunction(
+        CallGeneratorMethodIfWrapped,
+        this,
+        val,
+        "GeneratorReturn"
+      );
+    }
+
+    if (GeneratorObjectIsClosed(this)) {
+      return { value: val, done: true };
+    }
+
+    if (GeneratorIsRunning(this)) {
+      ThrowTypeError(JSMSG_NESTING_GENERATOR);
+    }
+  }
+
+  try {
+    var rval = { value: val, done: true };
+    return resumeGenerator(this, rval, "return");
+  } catch (e) {
+    if (!GeneratorObjectIsClosed(this)) {
+      GeneratorSetClosed(this);
+    }
+    throw e;
+  }
+}
+
+function InterpretGeneratorResume(gen, val, kind) {
+  // If we want to resume a generator in the interpreter, the script containing
+  // the resumeGenerator/JSOp::Resume also has to run in the interpreter. The
+  // forceInterpreter() call below compiles to a bytecode op that prevents us
+  // from JITing this script.
+  forceInterpreter();
+  if (kind === "next") {
+    return resumeGenerator(gen, val, "next");
+  }
+  if (kind === "throw") {
+    return resumeGenerator(gen, val, "throw");
+  }
+  assert(kind === "return", "Invalid resume kind");
+  return resumeGenerator(gen, val, "return");
+}