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-rw-r--r--dom/xbl/nsXBLProtoImplField.cpp510
1 files changed, 510 insertions, 0 deletions
diff --git a/dom/xbl/nsXBLProtoImplField.cpp b/dom/xbl/nsXBLProtoImplField.cpp
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+++ b/dom/xbl/nsXBLProtoImplField.cpp
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+/* -*- 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 "nsIAtom.h"
+#include "nsIContent.h"
+#include "nsString.h"
+#include "nsJSUtils.h"
+#include "jsapi.h"
+#include "js/CharacterEncoding.h"
+#include "nsUnicharUtils.h"
+#include "nsReadableUtils.h"
+#include "nsXBLProtoImplField.h"
+#include "nsIScriptContext.h"
+#include "nsIURI.h"
+#include "nsXBLSerialize.h"
+#include "nsXBLPrototypeBinding.h"
+#include "mozilla/AddonPathService.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/ElementBinding.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "nsGlobalWindow.h"
+#include "xpcpublic.h"
+#include "WrapperFactory.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+nsXBLProtoImplField::nsXBLProtoImplField(const char16_t* aName, const char16_t* aReadOnly)
+ : mNext(nullptr),
+ mFieldText(nullptr),
+ mFieldTextLength(0),
+ mLineNumber(0)
+{
+ MOZ_COUNT_CTOR(nsXBLProtoImplField);
+ mName = NS_strdup(aName); // XXXbz make more sense to use a stringbuffer?
+
+ mJSAttributes = JSPROP_ENUMERATE;
+ if (aReadOnly) {
+ nsAutoString readOnly; readOnly.Assign(aReadOnly);
+ if (readOnly.LowerCaseEqualsLiteral("true"))
+ mJSAttributes |= JSPROP_READONLY;
+ }
+}
+
+
+nsXBLProtoImplField::nsXBLProtoImplField(const bool aIsReadOnly)
+ : mNext(nullptr),
+ mFieldText(nullptr),
+ mFieldTextLength(0),
+ mLineNumber(0)
+{
+ MOZ_COUNT_CTOR(nsXBLProtoImplField);
+
+ mJSAttributes = JSPROP_ENUMERATE;
+ if (aIsReadOnly)
+ mJSAttributes |= JSPROP_READONLY;
+}
+
+nsXBLProtoImplField::~nsXBLProtoImplField()
+{
+ MOZ_COUNT_DTOR(nsXBLProtoImplField);
+ if (mFieldText)
+ free(mFieldText);
+ free(mName);
+ NS_CONTENT_DELETE_LIST_MEMBER(nsXBLProtoImplField, this, mNext);
+}
+
+void
+nsXBLProtoImplField::AppendFieldText(const nsAString& aText)
+{
+ if (mFieldText) {
+ nsDependentString fieldTextStr(mFieldText, mFieldTextLength);
+ nsAutoString newFieldText = fieldTextStr + aText;
+ char16_t* temp = mFieldText;
+ mFieldText = ToNewUnicode(newFieldText);
+ mFieldTextLength = newFieldText.Length();
+ free(temp);
+ }
+ else {
+ mFieldText = ToNewUnicode(aText);
+ mFieldTextLength = aText.Length();
+ }
+}
+
+// XBL fields are represented on elements inheriting that field a bit trickily.
+// When setting up the XBL prototype object, we install accessors for the fields
+// on the prototype object. Those accessors, when used, will then (via
+// InstallXBLField below) reify a property for the field onto the actual XBL-backed
+// element.
+//
+// The accessor property is a plain old property backed by a getter function and
+// a setter function. These properties are backed by the FieldGetter and
+// FieldSetter natives; they're created by InstallAccessors. The precise field to be
+// reified is identified using two extra slots on the getter/setter functions.
+// XBLPROTO_SLOT stores the XBL prototype object that provides the field.
+// FIELD_SLOT stores the name of the field, i.e. its JavaScript property name.
+//
+// This two-step field installation process -- creating an accessor on the
+// prototype, then have that reify an own property on the actual element -- is
+// admittedly convoluted. Better would be for XBL-backed elements to be proxies
+// that could resolve fields onto themselves. But given that XBL bindings are
+// associated with elements mutably -- you can add/remove/change -moz-binding
+// whenever you want, alas -- doing so would require all elements to be proxies,
+// which isn't performant now. So we do this two-step instead.
+static const uint32_t XBLPROTO_SLOT = 0;
+static const uint32_t FIELD_SLOT = 1;
+
+bool
+ValueHasISupportsPrivate(JS::Handle<JS::Value> v)
+{
+ if (!v.isObject()) {
+ return false;
+ }
+
+ const DOMJSClass* domClass = GetDOMClass(&v.toObject());
+ if (domClass) {
+ return domClass->mDOMObjectIsISupports;
+ }
+
+ const JSClass* clasp = ::JS_GetClass(&v.toObject());
+ const uint32_t HAS_PRIVATE_NSISUPPORTS =
+ JSCLASS_HAS_PRIVATE | JSCLASS_PRIVATE_IS_NSISUPPORTS;
+ return (clasp->flags & HAS_PRIVATE_NSISUPPORTS) == HAS_PRIVATE_NSISUPPORTS;
+}
+
+#ifdef DEBUG
+static bool
+ValueHasISupportsPrivate(JSContext* cx, const JS::Value& aVal)
+{
+ JS::Rooted<JS::Value> v(cx, aVal);
+ return ValueHasISupportsPrivate(v);
+}
+#endif
+
+// Define a shadowing property on |this| for the XBL field defined by the
+// contents of the callee's reserved slots. If the property was defined,
+// *installed will be true, and idp will be set to the property name that was
+// defined.
+static bool
+InstallXBLField(JSContext* cx,
+ JS::Handle<JSObject*> callee, JS::Handle<JSObject*> thisObj,
+ JS::MutableHandle<jsid> idp, bool* installed)
+{
+ *installed = false;
+
+ // First ensure |this| is a reasonable XBL bound node.
+ //
+ // FieldAccessorGuard already determined whether |thisObj| was acceptable as
+ // |this| in terms of not throwing a TypeError. Assert this for good measure.
+ MOZ_ASSERT(ValueHasISupportsPrivate(cx, JS::ObjectValue(*thisObj)));
+
+ // But there are some cases where we must accept |thisObj| but not install a
+ // property on it, or otherwise touch it. Hence this split of |this|-vetting
+ // duties.
+ nsCOMPtr<nsISupports> native = xpc::UnwrapReflectorToISupports(thisObj);
+ if (!native) {
+ // Looks like whatever |thisObj| is it's not our nsIContent. It might well
+ // be the proto our binding installed, however, where the private is the
+ // nsXBLDocumentInfo, so just baul out quietly. Do NOT throw an exception
+ // here.
+ //
+ // We could make this stricter by checking the class maybe, but whatever.
+ return true;
+ }
+
+ nsCOMPtr<nsIContent> xblNode = do_QueryInterface(native);
+ if (!xblNode) {
+ xpc::Throw(cx, NS_ERROR_UNEXPECTED);
+ return false;
+ }
+
+ // Now that |this| is okay, actually install the field.
+
+ // Because of the possibility (due to XBL binding inheritance, because each
+ // XBL binding lives in its own global object) that |this| might be in a
+ // different compartment from the callee (not to mention that this method can
+ // be called with an arbitrary |this| regardless of how insane XBL is), and
+ // because in this method we've entered |this|'s compartment (see in
+ // Field[GS]etter where we attempt a cross-compartment call), we must enter
+ // the callee's compartment to access its reserved slots.
+ nsXBLPrototypeBinding* protoBinding;
+ nsAutoJSString fieldName;
+ {
+ JSAutoCompartment ac(cx, callee);
+
+ JS::Rooted<JSObject*> xblProto(cx);
+ xblProto = &js::GetFunctionNativeReserved(callee, XBLPROTO_SLOT).toObject();
+
+ JS::Rooted<JS::Value> name(cx, js::GetFunctionNativeReserved(callee, FIELD_SLOT));
+ if (!fieldName.init(cx, name.toString())) {
+ return false;
+ }
+
+ MOZ_ALWAYS_TRUE(JS_ValueToId(cx, name, idp));
+
+ // If a separate XBL scope is being used, the callee is not same-compartment
+ // with the xbl prototype, and the object is a cross-compartment wrapper.
+ xblProto = js::UncheckedUnwrap(xblProto);
+ JSAutoCompartment ac2(cx, xblProto);
+ JS::Value slotVal = ::JS_GetReservedSlot(xblProto, 0);
+ protoBinding = static_cast<nsXBLPrototypeBinding*>(slotVal.toPrivate());
+ MOZ_ASSERT(protoBinding);
+ }
+
+ nsXBLProtoImplField* field = protoBinding->FindField(fieldName);
+ MOZ_ASSERT(field);
+
+ nsresult rv = field->InstallField(thisObj, protoBinding->DocURI(), installed);
+ if (NS_SUCCEEDED(rv)) {
+ return true;
+ }
+
+ if (!::JS_IsExceptionPending(cx)) {
+ xpc::Throw(cx, rv);
+ }
+ return false;
+}
+
+bool
+FieldGetterImpl(JSContext *cx, const JS::CallArgs& args)
+{
+ JS::Handle<JS::Value> thisv = args.thisv();
+ MOZ_ASSERT(ValueHasISupportsPrivate(thisv));
+
+ JS::Rooted<JSObject*> thisObj(cx, &thisv.toObject());
+
+ // We should be in the compartment of |this|. If we got here via nativeCall,
+ // |this| is not same-compartment with |callee|, and it's possible via
+ // asymmetric security semantics that |args.calleev()| is actually a security
+ // wrapper. In this case, we know we want to do an unsafe unwrap, and
+ // InstallXBLField knows how to handle cross-compartment pointers.
+ bool installed = false;
+ JS::Rooted<JSObject*> callee(cx, js::UncheckedUnwrap(&args.calleev().toObject()));
+ JS::Rooted<jsid> id(cx);
+ if (!InstallXBLField(cx, callee, thisObj, &id, &installed)) {
+ return false;
+ }
+
+ if (!installed) {
+ args.rval().setUndefined();
+ return true;
+ }
+
+ return JS_GetPropertyById(cx, thisObj, id, args.rval());
+}
+
+static bool
+FieldGetter(JSContext *cx, unsigned argc, JS::Value *vp)
+{
+ JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
+ return JS::CallNonGenericMethod<ValueHasISupportsPrivate, FieldGetterImpl>
+ (cx, args);
+}
+
+bool
+FieldSetterImpl(JSContext *cx, const JS::CallArgs& args)
+{
+ JS::Handle<JS::Value> thisv = args.thisv();
+ MOZ_ASSERT(ValueHasISupportsPrivate(thisv));
+
+ JS::Rooted<JSObject*> thisObj(cx, &thisv.toObject());
+
+ // We should be in the compartment of |this|. If we got here via nativeCall,
+ // |this| is not same-compartment with |callee|, and it's possible via
+ // asymmetric security semantics that |args.calleev()| is actually a security
+ // wrapper. In this case, we know we want to do an unsafe unwrap, and
+ // InstallXBLField knows how to handle cross-compartment pointers.
+ bool installed = false;
+ JS::Rooted<JSObject*> callee(cx, js::UncheckedUnwrap(&args.calleev().toObject()));
+ JS::Rooted<jsid> id(cx);
+ if (!InstallXBLField(cx, callee, thisObj, &id, &installed)) {
+ return false;
+ }
+
+ if (installed) {
+ if (!::JS_SetPropertyById(cx, thisObj, id, args.get(0))) {
+ return false;
+ }
+ }
+ args.rval().setUndefined();
+ return true;
+}
+
+static bool
+FieldSetter(JSContext *cx, unsigned argc, JS::Value *vp)
+{
+ JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
+ return JS::CallNonGenericMethod<ValueHasISupportsPrivate, FieldSetterImpl>
+ (cx, args);
+}
+
+nsresult
+nsXBLProtoImplField::InstallAccessors(JSContext* aCx,
+ JS::Handle<JSObject*> aTargetClassObject)
+{
+ MOZ_ASSERT(js::IsObjectInContextCompartment(aTargetClassObject, aCx));
+ JS::Rooted<JSObject*> globalObject(aCx, JS_GetGlobalForObject(aCx, aTargetClassObject));
+ JS::Rooted<JSObject*> scopeObject(aCx, xpc::GetXBLScopeOrGlobal(aCx, globalObject));
+ NS_ENSURE_TRUE(scopeObject, NS_ERROR_OUT_OF_MEMORY);
+
+ // Don't install it if the field is empty; see also InstallField which also must
+ // implement the not-empty requirement.
+ if (IsEmpty()) {
+ return NS_OK;
+ }
+
+ // Install a getter/setter pair which will resolve the field onto the actual
+ // object, when invoked.
+
+ // Get the field name as an id.
+ JS::Rooted<jsid> id(aCx);
+ JS::TwoByteChars chars(mName, NS_strlen(mName));
+ if (!JS_CharsToId(aCx, chars, &id))
+ return NS_ERROR_OUT_OF_MEMORY;
+
+ // Properties/Methods have historically taken precendence over fields. We
+ // install members first, so just bounce here if the property is already
+ // defined.
+ bool found = false;
+ if (!JS_AlreadyHasOwnPropertyById(aCx, aTargetClassObject, id, &found))
+ return NS_ERROR_FAILURE;
+ if (found)
+ return NS_OK;
+
+ // FieldGetter and FieldSetter need to run in the XBL scope so that they can
+ // see through any SOWs on their targets.
+
+ // First, enter the XBL scope, and compile the functions there.
+ JSAutoCompartment ac(aCx, scopeObject);
+ JS::Rooted<JS::Value> wrappedClassObj(aCx, JS::ObjectValue(*aTargetClassObject));
+ if (!JS_WrapValue(aCx, &wrappedClassObj))
+ return NS_ERROR_OUT_OF_MEMORY;
+
+ JS::Rooted<JSObject*> get(aCx,
+ JS_GetFunctionObject(js::NewFunctionByIdWithReserved(aCx, FieldGetter,
+ 0, 0, id)));
+ if (!get) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ js::SetFunctionNativeReserved(get, XBLPROTO_SLOT, wrappedClassObj);
+ js::SetFunctionNativeReserved(get, FIELD_SLOT,
+ JS::StringValue(JSID_TO_STRING(id)));
+
+ JS::Rooted<JSObject*> set(aCx,
+ JS_GetFunctionObject(js::NewFunctionByIdWithReserved(aCx, FieldSetter,
+ 1, 0, id)));
+ if (!set) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ js::SetFunctionNativeReserved(set, XBLPROTO_SLOT, wrappedClassObj);
+ js::SetFunctionNativeReserved(set, FIELD_SLOT,
+ JS::StringValue(JSID_TO_STRING(id)));
+
+ // Now, re-enter the class object's scope, wrap the getters/setters, and define
+ // them there.
+ JSAutoCompartment ac2(aCx, aTargetClassObject);
+ if (!JS_WrapObject(aCx, &get) || !JS_WrapObject(aCx, &set)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+
+ if (!::JS_DefinePropertyById(aCx, aTargetClassObject, id, JS::UndefinedHandleValue,
+ AccessorAttributes(),
+ JS_DATA_TO_FUNC_PTR(JSNative, get.get()),
+ JS_DATA_TO_FUNC_PTR(JSNative, set.get()))) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+
+ return NS_OK;
+}
+
+nsresult
+nsXBLProtoImplField::InstallField(JS::Handle<JSObject*> aBoundNode,
+ nsIURI* aBindingDocURI,
+ bool* aDidInstall) const
+{
+ NS_PRECONDITION(aBoundNode,
+ "uh-oh, bound node should NOT be null or bad things will "
+ "happen");
+
+ *aDidInstall = false;
+
+ // Empty fields are treated as not actually present.
+ if (IsEmpty()) {
+ return NS_OK;
+ }
+
+ nsAutoMicroTask mt;
+
+ nsAutoCString uriSpec;
+ nsresult rv = aBindingDocURI->GetSpec(uriSpec);
+ if (NS_WARN_IF(NS_FAILED(rv))) {
+ return rv;
+ }
+
+ nsIGlobalObject* globalObject = xpc::WindowGlobalOrNull(aBoundNode);
+ if (!globalObject) {
+ return NS_OK;
+ }
+
+ // We are going to run script via EvaluateString, so we need a script entry
+ // point, but as this is XBL related it does not appear in the HTML spec.
+ // We need an actual JSContext to do GetScopeForXBLExecution, and it needs to
+ // be in the compartment of globalObject. But we want our XBL execution scope
+ // to be our entry global.
+ AutoJSAPI jsapi;
+ if (!jsapi.Init(globalObject)) {
+ return NS_ERROR_UNEXPECTED;
+ }
+ MOZ_ASSERT(!::JS_IsExceptionPending(jsapi.cx()),
+ "Shouldn't get here when an exception is pending!");
+
+ JSAddonId* addonId = MapURIToAddonID(aBindingDocURI);
+
+ // Note: the UNWRAP_OBJECT may mutate boundNode; don't use it after that call.
+ JS::Rooted<JSObject*> boundNode(jsapi.cx(), aBoundNode);
+ Element* boundElement = nullptr;
+ rv = UNWRAP_OBJECT(Element, &boundNode, boundElement);
+ if (NS_WARN_IF(NS_FAILED(rv))) {
+ return rv;
+ }
+
+ // First, enter the xbl scope, build the element's scope chain, and use
+ // that as the scope chain for the evaluation.
+ JS::Rooted<JSObject*> scopeObject(jsapi.cx(),
+ xpc::GetScopeForXBLExecution(jsapi.cx(), aBoundNode, addonId));
+ NS_ENSURE_TRUE(scopeObject, NS_ERROR_OUT_OF_MEMORY);
+
+ AutoEntryScript aes(scopeObject, "XBL <field> initialization", true);
+ JSContext* cx = aes.cx();
+
+ JS::Rooted<JS::Value> result(cx);
+ JS::CompileOptions options(cx);
+ options.setFileAndLine(uriSpec.get(), mLineNumber)
+ .setVersion(JSVERSION_LATEST);
+ nsJSUtils::EvaluateOptions evalOptions(cx);
+ if (!nsJSUtils::GetScopeChainForElement(cx, boundElement,
+ evalOptions.scopeChain)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ rv = nsJSUtils::EvaluateString(cx, nsDependentString(mFieldText,
+ mFieldTextLength),
+ scopeObject, options, evalOptions, &result);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+
+ if (rv == NS_SUCCESS_DOM_SCRIPT_EVALUATION_THREW) {
+ // Report the exception now, before we try using the JSContext for
+ // the JS_DefineUCProperty call. Note that this reports in our current
+ // compartment, which is the XBL scope.
+ aes.ReportException();
+ }
+
+ // Now, enter the node's compartment, wrap the eval result, and define it on
+ // the bound node.
+ JSAutoCompartment ac2(cx, aBoundNode);
+ nsDependentString name(mName);
+ if (!JS_WrapValue(cx, &result) ||
+ !::JS_DefineUCProperty(cx, aBoundNode,
+ reinterpret_cast<const char16_t*>(mName),
+ name.Length(), result, mJSAttributes)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+
+ *aDidInstall = true;
+ return NS_OK;
+}
+
+nsresult
+nsXBLProtoImplField::Read(nsIObjectInputStream* aStream)
+{
+ nsAutoString name;
+ nsresult rv = aStream->ReadString(name);
+ NS_ENSURE_SUCCESS(rv, rv);
+ mName = ToNewUnicode(name);
+
+ rv = aStream->Read32(&mLineNumber);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ nsAutoString fieldText;
+ rv = aStream->ReadString(fieldText);
+ NS_ENSURE_SUCCESS(rv, rv);
+ mFieldTextLength = fieldText.Length();
+ if (mFieldTextLength)
+ mFieldText = ToNewUnicode(fieldText);
+
+ return NS_OK;
+}
+
+nsresult
+nsXBLProtoImplField::Write(nsIObjectOutputStream* aStream)
+{
+ XBLBindingSerializeDetails type = XBLBinding_Serialize_Field;
+
+ if (mJSAttributes & JSPROP_READONLY) {
+ type |= XBLBinding_Serialize_ReadOnly;
+ }
+
+ nsresult rv = aStream->Write8(type);
+ NS_ENSURE_SUCCESS(rv, rv);
+ rv = aStream->WriteWStringZ(mName);
+ NS_ENSURE_SUCCESS(rv, rv);
+ rv = aStream->Write32(mLineNumber);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ return aStream->WriteWStringZ(mFieldText ? mFieldText : u"");
+}