Add m-esr52 at 52.6.0

1 files changed, 268 insertions, 0 deletions

diff --git a/dom/bindings/DOMJSProxyHandler.h b/dom/bindings/DOMJSProxyHandler.h
new file mode 100644
index 000000000..1781649cc
--- /dev/null
+++ b/dom/bindings/DOMJSProxyHandler.h
@@ -0,0 +1,268 @@
+/* -*- 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/Attributes.h"
+#include "mozilla/Likely.h"
+
+#include "jsapi.h"
+#include "js/Proxy.h"
+#include "nsString.h"
+
+#define DOM_PROXY_OBJECT_SLOT js::PROXY_PRIVATE_SLOT
+
+namespace mozilla {
+namespace dom {
+
+enum {
+  /**
+   * DOM proxies have an extra slot for the expando object at index
+   * JSPROXYSLOT_EXPANDO.
+   *
+   * 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 JSPROXYSLOT_EXPANDO 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.)
+   */
+  JSPROXYSLOT_EXPANDO = 0
+};
+
+template<typename T> struct Prefable;
+
+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<JS::PropertyDescriptor> desc) const override;
+  virtual bool ownPropertyKeys(JSContext* cx, JS::Handle<JSObject*> proxy,
+                               JS::AutoIdVector &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::AutoIdVector &props) const override;
+
+  bool watch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+             JS::Handle<JSObject*> callable) const override;
+  bool unwatch(JSContext* cx, JS::Handle<JSObject*> proxy,
+               JS::Handle<jsid> id) 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::AutoIdVector& 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<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 *defined) 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 "external references" to this object.  If you are not
+   * nsWrapperCAche::ReleaseWrapper, you do NOT want to be calling this method.
+   *
+   * XXXbz if we nixed the DOM expando hash and just had a finalizer that
+   * cleared out the value in the ExpandoAndGeneration in the shadowing case,
+   * could we just get rid of this function altogether?
+   */
+  static void ClearExternalRefsForWrapperRelease(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 ExpandoAndGeneration.
+class ShadowingDOMProxyHandler : public DOMProxyHandler
+{
+  virtual void trace(JSTracer* trc, JSObject* proxy) const override;
+};
+
+inline bool IsDOMProxy(JSObject *obj)
+{
+    const js::Class* clasp = js::GetObjectClass(obj);
+    return clasp->isProxy() &&
+           js::GetProxyHandler(obj)->family() == &DOMProxyHandler::family;
+}
+
+inline const DOMProxyHandler*
+GetDOMProxyHandler(JSObject* obj)
+{
+  MOZ_ASSERT(IsDOMProxy(obj));
+  return static_cast<const DOMProxyHandler*>(js::GetProxyHandler(obj));
+}
+
+extern jsid s_length_id;
+
+// A return value of UINT32_MAX indicates "not an array index".  Note, in
+// particular, that UINT32_MAX itself is not a valid array index in general.
+inline uint32_t
+GetArrayIndexFromId(JSContext* cx, JS::Handle<jsid> id)
+{
+  // Much like js::IdIsIndex, except with a fast path for "length" and another
+  // fast path for starting with a lowercase ascii char.  Is that second one
+  // really needed?  I guess it is because StringIsArrayIndex is out of line...
+  if (MOZ_LIKELY(JSID_IS_INT(id))) {
+    return JSID_TO_INT(id);
+  }
+  if (MOZ_LIKELY(id == s_length_id)) {
+    return UINT32_MAX;
+  }
+  if (MOZ_UNLIKELY(!JSID_IS_ATOM(id))) {
+    return UINT32_MAX;
+  }
+
+  JSLinearString* str = js::AtomToLinearString(JSID_TO_ATOM(id));
+  char16_t s;
+  {
+    JS::AutoCheckCannotGC nogc;
+    if (js::LinearStringHasLatin1Chars(str)) {
+      s = *js::GetLatin1LinearStringChars(nogc, str);
+    } else {
+      s = *js::GetTwoByteLinearStringChars(nogc, str);
+    }
+  }
+  if (MOZ_LIKELY((unsigned)s >= 'a' && (unsigned)s <= 'z'))
+    return UINT32_MAX;
+
+  uint32_t i;
+  return js::StringIsArrayIndex(str, &i) ? i : UINT32_MAX;
+}
+
+inline bool
+IsArrayIndex(uint32_t index)
+{
+  return index < UINT32_MAX;
+}
+
+inline void
+FillPropertyDescriptor(JS::MutableHandle<JS::PropertyDescriptor> desc,
+                       JSObject* obj, bool readonly, bool enumerable = true)
+{
+  desc.object().set(obj);
+  desc.setAttributes((readonly ? JSPROP_READONLY : 0) |
+                     (enumerable ? JSPROP_ENUMERATE : 0));
+  desc.setGetter(nullptr);
+  desc.setSetter(nullptr);
+}
+
+inline void
+FillPropertyDescriptor(JS::MutableHandle<JS::PropertyDescriptor> desc,
+                       JSObject* obj, const JS::Value& v,
+                       bool readonly, bool enumerable = true)
+{
+  desc.value().set(v);
+  FillPropertyDescriptor(desc, obj, readonly, enumerable);
+}
+
+inline void
+FillPropertyDescriptor(JS::MutableHandle<JS::PropertyDescriptor> desc,
+                       JSObject* obj, unsigned attributes, const JS::Value& v)
+{
+  desc.object().set(obj);
+  desc.value().set(v);
+  desc.setAttributes(attributes);
+  desc.setGetter(nullptr);
+  desc.setSetter(nullptr);
+}
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_DOMProxyHandler_h */