1 files changed, 172 insertions, 0 deletions
diff --git a/js/xpconnect/src/JSServices.cpp b/js/xpconnect/src/JSServices.cpp
new file mode 100644
index 0000000000..cb8fe6cdca
--- /dev/null
+++ b/js/xpconnect/src/JSServices.cpp
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "xpcprivate.h"
+#include "StaticComponents.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/ProfilerLabels.h"
+#include "js/PropertyAndElement.h"  // JS_DefineProperty, JS_DefinePropertyById
+#include "js/String.h"              // JS::LinearStringHasLatin1Chars
+#include "nsJSUtils.h"
+
+using namespace mozilla;
+using namespace JS;
+
+namespace xpc {
+
+static bool Services_NewEnumerate(JSContext* cx, HandleObject obj,
+                                  MutableHandleIdVector properties,
+                                  bool enumerableOnly);
+static bool Services_Resolve(JSContext* cx, HandleObject obj, HandleId id,
+                             bool* resolvedp);
+static bool Services_MayResolve(const JSAtomState& names, jsid id,
+                                JSObject* maybeObj);
+
+static const JSClassOps sServices_ClassOps = {
+    nullptr,                // addProperty
+    nullptr,                // delProperty
+    nullptr,                // enumerate
+    Services_NewEnumerate,  // newEnumerate
+    Services_Resolve,       // resolve
+    Services_MayResolve,    // mayResolve
+    nullptr,                // finalize
+    nullptr,                // call
+    nullptr,                // construct
+    nullptr,                // trace
+};
+
+static const JSClass sServices_Class = {"JSServices", 0, &sServices_ClassOps};
+
+JSObject* NewJSServices(JSContext* cx) {
+  return JS_NewObject(cx, &sServices_Class);
+}
+
+static bool Services_NewEnumerate(JSContext* cx, HandleObject obj,
+                                  MutableHandleIdVector properties,
+                                  bool enumerableOnly) {
+  auto services = xpcom::StaticComponents::GetJSServices();
+
+  if (!properties.reserve(services.Length())) {
+    JS_ReportOutOfMemory(cx);
+    return false;
+  }
+
+  RootedId id(cx);
+  RootedString name(cx);
+  for (const auto& service : services) {
+    name = JS_AtomizeString(cx, service.Name().get());
+    if (!name || !JS_StringToId(cx, name, &id)) {
+      return false;
+    }
+    properties.infallibleAppend(id);
+  }
+
+  return true;
+}
+
+static JSLinearString* GetNameIfLatin1(jsid id) {
+  if (id.isString()) {
+    JSLinearString* name = id.toLinearString();
+    if (JS::LinearStringHasLatin1Chars(name)) {
+      return name;
+    }
+  }
+  return nullptr;
+}
+
+static bool GetServiceImpl(JSContext* cx, const xpcom::JSServiceEntry& service,
+                           JS::MutableHandleObject aObj, ErrorResult& aRv) {
+  nsresult rv;
+  nsCOMPtr<nsISupports> inst = service.Module().GetService(&rv);
+  if (!inst) {
+    aRv.Throw(rv);
+    return false;
+  }
+
+  auto ifaces = service.Interfaces();
+
+  if (ifaces.Length() == 0) {
+    // If we weren't given any interfaces, we're expecting either a WebIDL
+    // object or a wrapped JS object. In the former case, the object will handle
+    // its own wrapping, and there's nothing to do. In the latter case, we want
+    // to unwrap the underlying JS object.
+    if (nsCOMPtr<nsIXPConnectWrappedJS> wrappedJS = do_QueryInterface(inst)) {
+      aObj.set(wrappedJS->GetJSObject());
+      return !!aObj;
+    }
+  }
+
+  JS::RootedValue val(cx);
+
+  const nsIID* iid = ifaces.Length() ? ifaces[0] : nullptr;
+  xpcObjectHelper helper(inst);
+  if (!XPCConvert::NativeInterface2JSObject(cx, &val, helper, iid,
+                                            /* allowNativeWrapper */ true,
+                                            &rv)) {
+    aRv.Throw(rv);
+    return false;
+  }
+
+  if (ifaces.Length() > 1) {
+    auto* wn = XPCWrappedNative::Get(&val.toObject());
+    for (const nsIID* iid : Span(ifaces).From(1)) {
+      // Ignore any supplemental interfaces that aren't implemented. Tests do
+      // weird things with some services, and JS can generally handle the
+      // interfaces being absent.
+      Unused << wn->FindTearOff(cx, *iid);
+    }
+  }
+
+  aObj.set(&val.toObject());
+  return true;
+}
+
+static JSObject* GetService(JSContext* cx, const xpcom::JSServiceEntry& service,
+                            ErrorResult& aRv) {
+  JS::RootedObject obj(cx);
+  if (!GetServiceImpl(cx, service, &obj, aRv)) {
+    return nullptr;
+  }
+  return obj;
+}
+
+static bool Services_Resolve(JSContext* cx, HandleObject obj, HandleId id,
+                             bool* resolvedp) {
+  *resolvedp = false;
+  JSLinearString* name = GetNameIfLatin1(id);
+  if (!name) {
+    return true;
+  }
+
+  nsAutoJSLinearCString nameStr(name);
+  if (const auto* service = xpcom::JSServiceEntry::Lookup(nameStr)) {
+    AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_NONSENSITIVE("Services_Resolve",
+                                                       OTHER, service->Name());
+    *resolvedp = true;
+
+    ErrorResult rv;
+    JS::RootedValue val(cx);
+
+    val.setObjectOrNull(GetService(cx, *service, rv));
+    if (rv.MaybeSetPendingException(cx)) {
+      return false;
+    }
+
+    return JS_DefinePropertyById(cx, obj, id, val, JSPROP_ENUMERATE);
+  }
+  return true;
+}
+
+static bool Services_MayResolve(const JSAtomState& names, jsid id,
+                                JSObject* maybeObj) {
+  if (JSLinearString* name = GetNameIfLatin1(id)) {
+    nsAutoJSLinearCString nameStr(name);
+    return xpcom::JSServiceEntry::Lookup(nameStr);
+  }
+  return false;
+}
+
+}  // namespace xpc