Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 163 insertions, 0 deletions

diff --git a/dom/bindings/DOMJSProxyHandler.h b/dom/bindings/DOMJSProxyHandler.h
new file mode 100644
index 0000000000..8e68b32980
--- /dev/null
+++ b/dom/bindings/DOMJSProxyHandler.h
@@ -0,0 +1,163 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_DOMJSProxyHandler_h
+#define mozilla_dom_DOMJSProxyHandler_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Maybe.h"
+
+#include "jsapi.h"
+#include "js/Object.h"  // JS::GetClass
+#include "js/Proxy.h"
+
+namespace mozilla::dom {
+
+/**
+ * DOM proxies store the expando object in the private slot.
+ *
+ * The expando object is a plain JSObject whose properties correspond to
+ * "expandos" (custom properties set by the script author).
+ *
+ * The exact value stored in the proxy's private slot depends on whether the
+ * interface is annotated with the [OverrideBuiltins] extended attribute.
+ *
+ * If it is, the proxy is initialized with a PrivateValue, which contains a
+ * pointer to a JS::ExpandoAndGeneration object; this contains a pointer to
+ * the actual expando object as well as the "generation" of the object.  The
+ * proxy handler will trace the expando object stored in the
+ * JS::ExpandoAndGeneration while the proxy itself is alive.
+ *
+ * If it is not, the proxy is initialized with an UndefinedValue. In
+ * EnsureExpandoObject, it is set to an ObjectValue that points to the
+ * expando object directly. (It is set back to an UndefinedValue only when
+ * the object is about to die.)
+ */
+
+class BaseDOMProxyHandler : public js::BaseProxyHandler {
+ public:
+  explicit constexpr BaseDOMProxyHandler(const void* aProxyFamily,
+                                         bool aHasPrototype = false)
+      : js::BaseProxyHandler(aProxyFamily, aHasPrototype) {}
+
+  // Implementations of methods that can be implemented in terms of
+  // other lower-level methods.
+  bool getOwnPropertyDescriptor(
+      JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+      JS::MutableHandle<Maybe<JS::PropertyDescriptor>> desc) const override;
+  virtual bool ownPropertyKeys(
+      JSContext* cx, JS::Handle<JSObject*> proxy,
+      JS::MutableHandleVector<jsid> props) const override;
+
+  virtual bool getPrototypeIfOrdinary(
+      JSContext* cx, JS::Handle<JSObject*> proxy, bool* isOrdinary,
+      JS::MutableHandle<JSObject*> proto) const override;
+
+  // We override getOwnEnumerablePropertyKeys() and implement it directly
+  // instead of using the default implementation, which would call
+  // ownPropertyKeys and then filter out the non-enumerable ones. This avoids
+  // unnecessary work during enumeration.
+  virtual bool getOwnEnumerablePropertyKeys(
+      JSContext* cx, JS::Handle<JSObject*> proxy,
+      JS::MutableHandleVector<jsid> props) const override;
+
+ protected:
+  // Hook for subclasses to implement shared ownPropertyKeys()/keys()
+  // functionality.  The "flags" argument is either JSITER_OWNONLY (for keys())
+  // or JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS (for
+  // ownPropertyKeys()).
+  virtual bool ownPropNames(JSContext* cx, JS::Handle<JSObject*> proxy,
+                            unsigned flags,
+                            JS::MutableHandleVector<jsid> props) const = 0;
+
+  // Hook for subclasses to allow set() to ignore named props while other things
+  // that look at property descriptors see them.  This is intentionally not
+  // named getOwnPropertyDescriptor to avoid subclasses that override it hiding
+  // our public getOwnPropertyDescriptor.
+  virtual bool getOwnPropDescriptor(
+      JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+      bool ignoreNamedProps,
+      JS::MutableHandle<Maybe<JS::PropertyDescriptor>> desc) const = 0;
+};
+
+class DOMProxyHandler : public BaseDOMProxyHandler {
+ public:
+  constexpr DOMProxyHandler() : BaseDOMProxyHandler(&family) {}
+
+  bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy,
+                      JS::Handle<jsid> id,
+                      JS::Handle<JS::PropertyDescriptor> desc,
+                      JS::ObjectOpResult& result) const override {
+    bool unused;
+    return defineProperty(cx, proxy, id, desc, result, &unused);
+  }
+  virtual bool defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy,
+                              JS::Handle<jsid> id,
+                              JS::Handle<JS::PropertyDescriptor> desc,
+                              JS::ObjectOpResult& result, bool* done) const;
+  bool delete_(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+               JS::ObjectOpResult& result) const override;
+  bool preventExtensions(JSContext* cx, JS::Handle<JSObject*> proxy,
+                         JS::ObjectOpResult& result) const override;
+  bool isExtensible(JSContext* cx, JS::Handle<JSObject*> proxy,
+                    bool* extensible) const override;
+  bool set(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+           JS::Handle<JS::Value> v, JS::Handle<JS::Value> receiver,
+           JS::ObjectOpResult& result) const override;
+
+  /*
+   * If assigning to proxy[id] hits a named setter with OverrideBuiltins or
+   * an indexed setter, call it and set *done to true on success. Otherwise, set
+   * *done to false.
+   */
+  virtual bool setCustom(JSContext* cx, JS::Handle<JSObject*> proxy,
+                         JS::Handle<jsid> id, JS::Handle<JS::Value> v,
+                         bool* done) const;
+
+  /*
+   * Get the expando object for the given DOM proxy.
+   */
+  static JSObject* GetExpandoObject(JSObject* obj);
+
+  /*
+   * Clear the expando object for the given DOM proxy and return it.  This
+   * function will ensure that the returned object is exposed to active JS if
+   * the given object is exposed.
+   *
+   * GetAndClearExpandoObject does not DROP or clear the preserving wrapper
+   * flag.
+   */
+  static JSObject* GetAndClearExpandoObject(JSObject* obj);
+
+  /*
+   * Ensure that the given proxy (obj) has an expando object, and return it.
+   * Returns null on failure.
+   */
+  static JSObject* EnsureExpandoObject(JSContext* cx,
+                                       JS::Handle<JSObject*> obj);
+
+  static const char family;
+};
+
+// Class used by shadowing handlers (the ones that have [OverrideBuiltins].
+// This handles tracing the expando in JS::ExpandoAndGeneration.
+class ShadowingDOMProxyHandler : public DOMProxyHandler {
+  virtual void trace(JSTracer* trc, JSObject* proxy) const override;
+};
+
+inline bool IsDOMProxy(JSObject* obj) {
+  return js::IsProxy(obj) &&
+         js::GetProxyHandler(obj)->family() == &DOMProxyHandler::family;
+}
+
+inline const DOMProxyHandler* GetDOMProxyHandler(JSObject* obj) {
+  MOZ_ASSERT(IsDOMProxy(obj));
+  return static_cast<const DOMProxyHandler*>(js::GetProxyHandler(obj));
+}
+
+}  // namespace mozilla::dom
+
+#endif /* mozilla_dom_DOMProxyHandler_h */