Add m-esr52 at 52.6.0

1 files changed, 331 insertions, 0 deletions

diff --git a/dom/bindings/CallbackObject.cpp b/dom/bindings/CallbackObject.cpp
new file mode 100644
index 000000000..7c7d2c6b4
--- /dev/null
+++ b/dom/bindings/CallbackObject.cpp
@@ -0,0 +1,331 @@
+/* -*- 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 "mozilla/dom/CallbackObject.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "jsfriendapi.h"
+#include "nsIScriptGlobalObject.h"
+#include "nsIXPConnect.h"
+#include "nsIScriptContext.h"
+#include "nsPIDOMWindow.h"
+#include "nsJSUtils.h"
+#include "xpcprivate.h"
+#include "WorkerPrivate.h"
+#include "nsGlobalWindow.h"
+#include "WorkerScope.h"
+#include "jsapi.h"
+#include "nsJSPrincipals.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CallbackObject)
+  NS_INTERFACE_MAP_ENTRY(mozilla::dom::CallbackObject)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(CallbackObject)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(CallbackObject)
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(CallbackObject)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CallbackObject)
+  tmp->DropJSObjects();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mIncumbentGlobal)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CallbackObject)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIncumbentGlobal)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CallbackObject)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mCallback)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mCreationStack)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mIncumbentJSGlobal)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+void
+CallbackObject::Trace(JSTracer* aTracer)
+{
+  JS::TraceEdge(aTracer, &mCallback, "CallbackObject.mCallback");
+  JS::TraceEdge(aTracer, &mCreationStack, "CallbackObject.mCreationStack");
+  JS::TraceEdge(aTracer, &mIncumbentJSGlobal,
+                "CallbackObject.mIncumbentJSGlobal");
+}
+
+void
+CallbackObject::HoldJSObjectsIfMoreThanOneOwner()
+{
+  MOZ_ASSERT(mRefCnt.get() > 0);
+  if (mRefCnt.get() > 1) {
+    mozilla::HoldJSObjects(this);
+  } else {
+    // We can just forget all our stuff.
+    ClearJSReferences();
+  }
+}
+
+CallbackObject::CallSetup::CallSetup(CallbackObject* aCallback,
+                                     ErrorResult& aRv,
+                                     const char* aExecutionReason,
+                                     ExceptionHandling aExceptionHandling,
+                                     JSCompartment* aCompartment,
+                                     bool aIsJSImplementedWebIDL)
+  : mCx(nullptr)
+  , mCompartment(aCompartment)
+  , mErrorResult(aRv)
+  , mExceptionHandling(aExceptionHandling)
+  , mIsMainThread(NS_IsMainThread())
+{
+  if (mIsMainThread) {
+    nsContentUtils::EnterMicroTask();
+  }
+
+  // Compute the caller's subject principal (if necessary) early, before we
+  // do anything that might perturb the relevant state.
+  nsIPrincipal* webIDLCallerPrincipal = nullptr;
+  if (aIsJSImplementedWebIDL) {
+    webIDLCallerPrincipal = nsContentUtils::SubjectPrincipalOrSystemIfNativeCaller();
+  }
+
+  // First, find the real underlying callback.
+  JSObject* realCallback = js::UncheckedUnwrap(aCallback->CallbackPreserveColor());
+  nsIGlobalObject* globalObject = nullptr;
+
+  JSContext* cx;
+  {
+    // Bug 955660: we cannot do "proper" rooting here because we need the
+    // global to get a context. Everything here is simple getters that cannot
+    // GC, so just paper over the necessary dataflow inversion.
+    JS::AutoSuppressGCAnalysis nogc;
+
+    // Now get the global for this callback. Note that for the case of
+    // JS-implemented WebIDL we never have a window here.
+    nsGlobalWindow* win = mIsMainThread && !aIsJSImplementedWebIDL
+                        ? xpc::WindowGlobalOrNull(realCallback)
+                        : nullptr;
+    if (win) {
+      MOZ_ASSERT(win->IsInnerWindow());
+      // We don't want to run script in windows that have been navigated away
+      // from.
+      if (!win->AsInner()->HasActiveDocument()) {
+        aRv.ThrowDOMException(NS_ERROR_DOM_NOT_SUPPORTED_ERR,
+          NS_LITERAL_CSTRING("Refusing to execute function from window "
+                             "whose document is no longer active."));
+        return;
+      }
+      globalObject = win;
+    } else {
+      // No DOM Window. Store the global.
+      JSObject* global = js::GetGlobalForObjectCrossCompartment(realCallback);
+      globalObject = xpc::NativeGlobal(global);
+      MOZ_ASSERT(globalObject);
+    }
+
+    // Bail out if there's no useful global. This seems to happen intermittently
+    // on gaia-ui tests, probably because nsInProcessTabChildGlobal is returning
+    // null in some kind of teardown state.
+    if (!globalObject->GetGlobalJSObject()) {
+      aRv.ThrowDOMException(NS_ERROR_DOM_NOT_SUPPORTED_ERR,
+        NS_LITERAL_CSTRING("Refusing to execute function from global which is "
+                           "being torn down."));
+      return;
+    }
+
+    mAutoEntryScript.emplace(globalObject, aExecutionReason, mIsMainThread);
+    mAutoEntryScript->SetWebIDLCallerPrincipal(webIDLCallerPrincipal);
+    nsIGlobalObject* incumbent = aCallback->IncumbentGlobalOrNull();
+    if (incumbent) {
+      // The callback object traces its incumbent JS global, so in general it
+      // should be alive here. However, it's possible that we could run afoul
+      // of the same IPC global weirdness described above, wherein the
+      // nsIGlobalObject has severed its reference to the JS global. Let's just
+      // be safe here, so that nobody has to waste a day debugging gaia-ui tests.
+      if (!incumbent->GetGlobalJSObject()) {
+      aRv.ThrowDOMException(NS_ERROR_DOM_NOT_SUPPORTED_ERR,
+        NS_LITERAL_CSTRING("Refusing to execute function because our "
+                           "incumbent global is being torn down."));
+        return;
+      }
+      mAutoIncumbentScript.emplace(incumbent);
+    }
+
+    cx = mAutoEntryScript->cx();
+
+    // Unmark the callable (by invoking Callback() and not the CallbackPreserveColor()
+    // variant), and stick it in a Rooted before it can go gray again.
+    // Nothing before us in this function can trigger a CC, so it's safe to wait
+    // until here it do the unmark. This allows us to construct mRootedCallable
+    // with the cx from mAutoEntryScript, avoiding the cost of finding another
+    // JSContext. (Rooted<> does not care about requests or compartments.)
+    mRootedCallable.emplace(cx, aCallback->Callback());
+  }
+
+  // JS-implemented WebIDL is always OK to run, since it runs with Chrome
+  // privileges anyway.
+  if (mIsMainThread && !aIsJSImplementedWebIDL) {
+    // Check that it's ok to run this callback at all.
+    // Make sure to use realCallback to get the global of the callback object,
+    // not the wrapper.
+    bool allowed = xpc::Scriptability::Get(realCallback).Allowed();
+
+    if (!allowed) {
+      aRv.ThrowDOMException(NS_ERROR_DOM_NOT_SUPPORTED_ERR,
+        NS_LITERAL_CSTRING("Refusing to execute function from global in which "
+                           "script is disabled."));
+      return;
+    }
+  }
+
+  mAsyncStack.emplace(cx, aCallback->GetCreationStack());
+  if (*mAsyncStack) {
+    mAsyncStackSetter.emplace(cx, *mAsyncStack, aExecutionReason);
+  }
+
+  // Enter the compartment of our callback, so we can actually work with it.
+  //
+  // Note that if the callback is a wrapper, this will not be the same
+  // compartment that we ended up in with mAutoEntryScript above, because the
+  // entry point is based off of the unwrapped callback (realCallback).
+  mAc.emplace(cx, *mRootedCallable);
+
+  // And now we're ready to go.
+  mCx = cx;
+}
+
+bool
+CallbackObject::CallSetup::ShouldRethrowException(JS::Handle<JS::Value> aException)
+{
+  if (mExceptionHandling == eRethrowExceptions) {
+    if (!mCompartment) {
+      // Caller didn't ask us to filter for only exceptions we subsume.
+      return true;
+    }
+
+    // On workers, we don't have nsIPrincipals to work with.  But we also only
+    // have one compartment, so check whether mCompartment is the same as the
+    // current compartment of mCx.
+    if (mCompartment == js::GetContextCompartment(mCx)) {
+      return true;
+    }
+
+    MOZ_ASSERT(NS_IsMainThread());
+
+    // At this point mCx is in the compartment of our unwrapped callback, so
+    // just check whether the principal of mCompartment subsumes that of the
+    // current compartment/global of mCx.
+    nsIPrincipal* callerPrincipal =
+      nsJSPrincipals::get(JS_GetCompartmentPrincipals(mCompartment));
+    nsIPrincipal* calleePrincipal = nsContentUtils::SubjectPrincipal();
+    if (callerPrincipal->SubsumesConsideringDomain(calleePrincipal)) {
+      return true;
+    }
+  }
+
+  MOZ_ASSERT(mCompartment);
+
+  // Now we only want to throw an exception to the caller if the object that was
+  // thrown is in the caller compartment (which we stored in mCompartment).
+
+  if (!aException.isObject()) {
+    return false;
+  }
+
+  JS::Rooted<JSObject*> obj(mCx, &aException.toObject());
+  obj = js::UncheckedUnwrap(obj, /* stopAtWindowProxy = */ false);
+  return js::GetObjectCompartment(obj) == mCompartment;
+}
+
+CallbackObject::CallSetup::~CallSetup()
+{
+  // To get our nesting right we have to destroy our JSAutoCompartment first.
+  // In particular, we want to do this before we try reporting any exceptions,
+  // so we end up reporting them while in the compartment of our entry point,
+  // not whatever cross-compartment wrappper mCallback might be.
+  // Be careful: the JSAutoCompartment might not have been constructed at all!
+  mAc.reset();
+
+  // Now, if we have a JSContext, report any pending errors on it, unless we
+  // were told to re-throw them.
+  if (mCx) {
+    bool needToDealWithException = mAutoEntryScript->HasException();
+    if ((mCompartment && mExceptionHandling == eRethrowContentExceptions) ||
+        mExceptionHandling == eRethrowExceptions) {
+      mErrorResult.MightThrowJSException();
+      if (needToDealWithException) {
+        JS::Rooted<JS::Value> exn(mCx);
+        if (mAutoEntryScript->PeekException(&exn) &&
+            ShouldRethrowException(exn)) {
+          mAutoEntryScript->ClearException();
+          MOZ_ASSERT(!mAutoEntryScript->HasException());
+          mErrorResult.ThrowJSException(mCx, exn);
+          needToDealWithException = false;
+        }
+      }
+    }
+
+    if (needToDealWithException) {
+      // Either we're supposed to report our exceptions, or we're supposed to
+      // re-throw them but we failed to get the exception value.  Either way,
+      // we'll just report the pending exception, if any, once ~mAutoEntryScript
+      // runs.  Note that we've already run ~mAc, effectively, so we don't have
+      // to worry about ordering here.
+      if (mErrorResult.IsJSContextException()) {
+        // XXXkhuey bug 1117269.  When this is fixed, please consider fixing
+        // ThrowExceptionValueIfSafe over in Exceptions.cpp in the same way.
+
+        // IsJSContextException shouldn't be true anymore because we will report
+        // the exception on the JSContext ... so throw something else.
+        mErrorResult.Throw(NS_ERROR_UNEXPECTED);
+      }
+    }
+  }
+
+  mAutoIncumbentScript.reset();
+  mAutoEntryScript.reset();
+
+  // It is important that this is the last thing we do, after leaving the
+  // compartment and undoing all our entry/incumbent script changes
+  if (mIsMainThread) {
+    nsContentUtils::LeaveMicroTask();
+  }
+}
+
+already_AddRefed<nsISupports>
+CallbackObjectHolderBase::ToXPCOMCallback(CallbackObject* aCallback,
+                                          const nsIID& aIID) const
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!aCallback) {
+    return nullptr;
+  }
+
+  // We don't init the AutoJSAPI with our callback because we don't want it
+  // reporting errors to its global's onerror handlers.
+  AutoJSAPI jsapi;
+  jsapi.Init();
+  JSContext* cx = jsapi.cx();
+
+  JS::Rooted<JSObject*> callback(cx, aCallback->Callback());
+
+  JSAutoCompartment ac(cx, callback);
+  RefPtr<nsXPCWrappedJS> wrappedJS;
+  nsresult rv =
+    nsXPCWrappedJS::GetNewOrUsed(callback, aIID, getter_AddRefs(wrappedJS));
+  if (NS_FAILED(rv) || !wrappedJS) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsISupports> retval;
+  rv = wrappedJS->QueryInterface(aIID, getter_AddRefs(retval));
+  if (NS_FAILED(rv)) {
+    return nullptr;
+  }
+
+  return retval.forget();
+}
+
+} // namespace dom
+} // namespace mozilla