The Tor Browser: comparison dom/base/ScriptSettings.cpp

--1:000000000000
+:131f3e28a9d5
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+// vim: ft=cpp tw=78 sw=2 et ts=2
+/* 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/ScriptSettings.h"
+#include "mozilla/ThreadLocal.h"
+#include "mozilla/Assertions.h"
+#include "jsapi.h"
+#include "xpcpublic.h"
+#include "nsIGlobalObject.h"
+#include "nsIScriptGlobalObject.h"
+#include "nsIScriptContext.h"
+#include "nsContentUtils.h"
+#include "nsTArray.h"
+#include "nsJSUtils.h"
+namespace mozilla {
+namespace dom {
+class ScriptSettingsStack;
+static mozilla::ThreadLocal<ScriptSettingsStack*> sScriptSettingsTLS;
+ScriptSettingsStackEntry ScriptSettingsStackEntry::NoJSAPISingleton;
+class ScriptSettingsStack {
+public:
+static ScriptSettingsStack& Ref() {
+return *sScriptSettingsTLS.get();
+}
+ScriptSettingsStack() {};
+void Push(ScriptSettingsStackEntry* aSettings) {
+// The bottom-most entry must always be a candidate entry point.
+MOZ_ASSERT_IF(mStack.Length() == 0 || mStack.LastElement()->NoJSAPI(),
+aSettings->mIsCandidateEntryPoint);
+mStack.AppendElement(aSettings);
+}
+void PushNoJSAPI() {
+mStack.AppendElement(&ScriptSettingsStackEntry::NoJSAPISingleton);
+}
+void Pop() {
+MOZ_ASSERT(mStack.Length() > 0);
+mStack.RemoveElementAt(mStack.Length() - 1);
+}
+ScriptSettingsStackEntry* Incumbent() {
+if (!mStack.Length()) {
+return nullptr;
+}
+return mStack.LastElement();
+}
+nsIGlobalObject* IncumbentGlobal() {
+ScriptSettingsStackEntry *entry = Incumbent();
+return entry ? entry->mGlobalObject : nullptr;
+}
+ScriptSettingsStackEntry* EntryPoint() {
+if (!mStack.Length())
+return nullptr;
+for (int i = mStack.Length() - 1; i >= 0; --i) {
+if (mStack[i]->mIsCandidateEntryPoint) {
+return mStack[i];
+}
+}
+MOZ_ASSUME_UNREACHABLE("Non-empty stack should always have an entry point");
+}
+nsIGlobalObject* EntryGlobal() {
+ScriptSettingsStackEntry *entry = EntryPoint();
+return entry ? entry->mGlobalObject : nullptr;
+}
+private:
+// These pointers are caller-owned.
+nsTArray<ScriptSettingsStackEntry*> mStack;
+};
+void
+InitScriptSettings()
+{
+if (!sScriptSettingsTLS.initialized()) {
+bool success = sScriptSettingsTLS.init();
+if (!success) {
+MOZ_CRASH();
+}
+}
+ScriptSettingsStack* ptr = new ScriptSettingsStack();
+sScriptSettingsTLS.set(ptr);
+}
+void DestroyScriptSettings()
+{
+ScriptSettingsStack* ptr = sScriptSettingsTLS.get();
+MOZ_ASSERT(ptr);
+sScriptSettingsTLS.set(nullptr);
+delete ptr;
+}
+// This mostly gets the entry global, but doesn't entirely match the spec in
+// certain edge cases. It's good enough for some purposes, but not others. If
+// you want to call this function, ping bholley and describe your use-case.
+nsIGlobalObject*
+BrokenGetEntryGlobal()
+{
+// We need the current JSContext in order to check the JS for
+// scripted frames that may have appeared since anyone last
+// manipulated the stack. If it's null, that means that there
+// must be no entry global on the stack.
+JSContext *cx = nsContentUtils::GetCurrentJSContextForThread();
+if (!cx) {
+MOZ_ASSERT(ScriptSettingsStack::Ref().EntryGlobal() == nullptr);
+return nullptr;
+}
+return nsJSUtils::GetDynamicScriptGlobal(cx);
+}
+// Note: When we're ready to expose it, GetEntryGlobal will look similar to
+// GetIncumbentGlobal below.
+nsIGlobalObject*
+GetIncumbentGlobal()
+{
+// We need the current JSContext in order to check the JS for
+// scripted frames that may have appeared since anyone last
+// manipulated the stack. If it's null, that means that there
+// must be no entry global on the stack, and therefore no incumbent
+// global either.
+JSContext *cx = nsContentUtils::GetCurrentJSContextForThread();
+if (!cx) {
+MOZ_ASSERT(ScriptSettingsStack::Ref().EntryGlobal() == nullptr);
+return nullptr;
+}
+// See what the JS engine has to say. If we've got a scripted caller
+// override in place, the JS engine will lie to us and pretend that
+// there's nothing on the JS stack, which will cause us to check the
+// incumbent script stack below.
+if (JSObject *global = JS::GetScriptedCallerGlobal(cx)) {
+return xpc::GetNativeForGlobal(global);
+}
+// Ok, nothing from the JS engine. Let's use whatever's on the
+// explicit stack.
+return ScriptSettingsStack::Ref().IncumbentGlobal();
+}
+nsIPrincipal*
+GetWebIDLCallerPrincipal()
+{
+MOZ_ASSERT(NS_IsMainThread());
+ScriptSettingsStackEntry *entry = ScriptSettingsStack::Ref().EntryPoint();
+// If we have an entry point that is not the NoJSAPI singleton, we know it
+// must be an AutoEntryScript.
+if (!entry || entry->NoJSAPI()) {
+return nullptr;
+}
+AutoEntryScript* aes = static_cast<AutoEntryScript*>(entry);
+// We can't yet rely on the Script Settings Stack to properly determine the
+// entry script, because there are still lots of places in the tree where we
+// don't yet use an AutoEntryScript (bug 951991 tracks this work). In the
+// mean time though, we can make some observations to hack around the
+// problem:
+//
+// (1) All calls into JS-implemented WebIDL go through CallSetup, which goes
+//     through AutoEntryScript.
+// (2) The top candidate entry point in the Script Settings Stack is the
+//     entry point if and only if no other JSContexts have been pushed on
+//     top of the push made by that entry's AutoEntryScript.
+//
+// Because of (1), all of the cases where we might return a non-null
+// WebIDL Caller are guaranteed to have put an entry on the Script Settings
+// Stack, so we can restrict our search to that. Moreover, (2) gives us a
+// criterion to determine whether an entry in the Script Setting Stack means
+// that we should return a non-null WebIDL Caller.
+//
+// Once we fix bug 951991, this can all be simplified.
+if (!aes->CxPusherIsStackTop()) {
+return nullptr;
+}
+return aes->mWebIDLCallerPrincipal;
+}
+static JSContext*
+FindJSContext(nsIGlobalObject* aGlobalObject)
+{
+MOZ_ASSERT(NS_IsMainThread());
+JSContext *cx = nullptr;
+nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(aGlobalObject);
+if (sgo && sgo->GetScriptContext()) {
+cx = sgo->GetScriptContext()->GetNativeContext();
+}
+if (!cx) {
+cx = nsContentUtils::GetSafeJSContext();
+}
+return cx;
+}
+AutoJSAPI::AutoJSAPI()
+: mCx(nsContentUtils::GetDefaultJSContextForThread())
+{
+if (NS_IsMainThread()) {
+mCxPusher.construct(mCx);
+}
+// Leave the cx in a null compartment.
+mNullAc.construct(mCx);
+}
+AutoJSAPI::AutoJSAPI(JSContext *aCx, bool aIsMainThread, bool aSkipNullAc)
+: mCx(aCx)
+{
+MOZ_ASSERT_IF(aIsMainThread, NS_IsMainThread());
+if (aIsMainThread) {
+mCxPusher.construct(mCx);
+}
+// In general we want to leave the cx in a null compartment, but we let
+// subclasses skip this if they plan to immediately enter a compartment.
+if (!aSkipNullAc) {
+mNullAc.construct(mCx);
+}
+}
+AutoJSAPIWithErrorsReportedToWindow::AutoJSAPIWithErrorsReportedToWindow(nsIScriptContext* aScx)
+: AutoJSAPI(aScx->GetNativeContext(), /* aIsMainThread = */ true)
+{
+}
+AutoJSAPIWithErrorsReportedToWindow::AutoJSAPIWithErrorsReportedToWindow(nsIGlobalObject* aGlobalObject)
+: AutoJSAPI(FindJSContext(aGlobalObject), /* aIsMainThread = */ true)
+{
+}
+AutoEntryScript::AutoEntryScript(nsIGlobalObject* aGlobalObject,
+bool aIsMainThread,
+JSContext* aCx)
+: AutoJSAPI(aCx ? aCx : FindJSContext(aGlobalObject), aIsMainThread, /* aSkipNullAc = */ true)
+, ScriptSettingsStackEntry(aGlobalObject, /* aCandidate = */ true)
+, mAc(cx(), aGlobalObject->GetGlobalJSObject())
+, mStack(ScriptSettingsStack::Ref())
+{
+MOZ_ASSERT(aGlobalObject);
+MOZ_ASSERT_IF(!aCx, aIsMainThread); // cx is mandatory off-main-thread.
+MOZ_ASSERT_IF(aCx && aIsMainThread, aCx == FindJSContext(aGlobalObject));
+mStack.Push(this);
+}
+AutoEntryScript::~AutoEntryScript()
+{
+MOZ_ASSERT(mStack.Incumbent() == this);
+mStack.Pop();
+}
+AutoIncumbentScript::AutoIncumbentScript(nsIGlobalObject* aGlobalObject)
+: ScriptSettingsStackEntry(aGlobalObject, /* aCandidate = */ false)
+, mStack(ScriptSettingsStack::Ref())
+, mCallerOverride(nsContentUtils::GetCurrentJSContextForThread())
+{
+mStack.Push(this);
+}
+AutoIncumbentScript::~AutoIncumbentScript()
+{
+MOZ_ASSERT(mStack.Incumbent() == this);
+mStack.Pop();
+}
+AutoNoJSAPI::AutoNoJSAPI(bool aIsMainThread)
+: mStack(ScriptSettingsStack::Ref())
+{
+MOZ_ASSERT_IF(nsContentUtils::GetCurrentJSContextForThread(),
+!JS_IsExceptionPending(nsContentUtils::GetCurrentJSContextForThread()));
+if (aIsMainThread) {
+mCxPusher.construct(static_cast<JSContext*>(nullptr),
+/* aAllowNull = */ true);
+}
+mStack.PushNoJSAPI();
+}
+AutoNoJSAPI::~AutoNoJSAPI()
+{
+mStack.Pop();
+}
+} // namespace dom
+} // namespace mozilla

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comparison: dom/base/ScriptSettings.cpp

dom/base/ScriptSettings.cpp