Bug 1271650 - Implement a C++ interface for DebuggerFrame.isLive. r=fitzgen

js/src/vm/Debugger.cpp

@@ -7078,6 +7078,8 @@ DebuggerFrame::create(JSContext* cx, HandleObject proto, AbstractFramePtr refere
 DebuggerFrame::getCallee(JSContext* cx, Handle<DebuggerFrame*> frame,
                          MutableHandle<DebuggerObject*> result)
 {
+    MOZ_ASSERT(frame->isLive());
+
     AbstractFramePtr referent = DebuggerFrame::getReferent(frame);
     if (!referent.isFunctionFrame()) {
         result.set(nullptr);
@@ -7093,6 +7095,8 @@ DebuggerFrame::getCallee(JSContext* cx, Handle<DebuggerFrame*> frame,
 /* static */ bool
 DebuggerFrame::getIsConstructing(JSContext* cx, Handle<DebuggerFrame*> frame, bool& result)
 {
+    MOZ_ASSERT(frame->isLive());
+
     Maybe<ScriptFrameIter> maybeIter;
     if (!DebuggerFrame::getScriptFrameIter(cx, frame, maybeIter))
         return false;
@@ -7143,6 +7147,8 @@ UpdateFrameIterPc(FrameIter& iter)
 DebuggerFrame::getEnvironment(JSContext* cx, Handle<DebuggerFrame*> frame,
                               MutableHandle<DebuggerEnvironment*> result)
 {
+    MOZ_ASSERT(frame->isLive());
+
     Debugger* dbg = frame->owner();
 
     Maybe<ScriptFrameIter> maybeIter;
@@ -7168,6 +7174,24 @@ DebuggerFrame::getIsGenerator(Handle<DebuggerFrame*> frame)
     return DebuggerFrame::getReferent(frame).script()->isGenerator();
 }
 
+/* statuc */ bool
+DebuggerFrame::isLive() const
+{
+    return !!getPrivate();
+}
+
+/* static */ bool
+DebuggerFrame::requireLive(JSContext* cx, Handle<DebuggerFrame*> frame)
+{
+    if (!frame->isLive()) {
+        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_LIVE,
+                             "Debugger.Frame");
+        return false;
+    }
+
+    return true;
+}
+
 /* static */ AbstractFramePtr
 DebuggerFrame::getReferent(Handle<DebuggerFrame*> frame)
 {
@@ -7235,7 +7259,7 @@ DebuggerFrame::checkThis(JSContext* cx, const CallArgs& args, const char* fnname
         return nullptr;
     }
 
-    DebuggerFrame* nthisobj = &thisobj->as<DebuggerFrame>();
+    Rooted<DebuggerFrame*> frame(cx, &thisobj->as<DebuggerFrame>());
 
     /*
      * Forbid Debugger.Frame.prototype, which is of class DebuggerFrame::class_
@@ -7243,19 +7267,18 @@ DebuggerFrame::checkThis(JSContext* cx, const CallArgs& args, const char* fnname
      * is distinguished by having a nullptr private value. Also, forbid popped
      * frames.
      */
-    if (!nthisobj->getPrivate()) {
+    if (!frame->getPrivate() &&
-        if (nthisobj->getReservedSlot(JSSLOT_DEBUGFRAME_OWNER).isUndefined()) {
+        frame->getReservedSlot(JSSLOT_DEBUGFRAME_OWNER).isUndefined())
-            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
+    {
-                                 "Debugger.Frame", fnname, "prototype object");
+        JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
-            return nullptr;
+                             "Debugger.Frame", fnname, "prototype object");
-        }
+        return nullptr;
-        if (checkLive) {
-            JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_DEBUG_NOT_LIVE,
-                                 "Debugger.Frame");
-            return nullptr;
-        }
     }
-    return nthisobj;
+
+    if (checkLive && !DebuggerFrame::requireLive(cx, frame))
+        return nullptr;
+
+    return frame;
 }
 
 /*
@@ -7612,15 +7635,15 @@ DebuggerFrame_getOffset(JSContext* cx, unsigned argc, Value* vp)
     return true;
 }
 
-static bool
+/* static */ bool
-DebuggerFrame_getLive(JSContext* cx, unsigned argc, Value* vp)
+DebuggerFrame::liveGetter(JSContext* cx, unsigned argc, Value* vp)
 {
     CallArgs args = CallArgsFromVp(argc, vp);
-    NativeObject* thisobj = DebuggerFrame::checkThis(cx, args, "get live", false);
+    Rooted<DebuggerFrame*> frame(cx, DebuggerFrame::checkThis(cx, args, "get live", false));
-    if (!thisobj)
+    if (!frame)
         return false;
-    bool hasFrame = !!thisobj->getPrivate();
+
-    args.rval().setBoolean(hasFrame);
+    args.rval().setBoolean(frame->isLive());
     return true;
 }
 
@@ -7930,7 +7953,7 @@ const JSPropertySpec DebuggerFrame::properties_[] = {
     JS_PSG("constructing", DebuggerFrame::constructingGetter, 0),
     JS_PSG("environment", DebuggerFrame::environmentGetter, 0),
     JS_PSG("generator", DebuggerFrame::generatorGetter, 0),
-    JS_PSG("live", DebuggerFrame_getLive, 0),
+    JS_PSG("live", DebuggerFrame::liveGetter, 0),
     JS_PSG("offset", DebuggerFrame_getOffset, 0),
     JS_PSG("older", DebuggerFrame_getOlder, 0),
     JS_PSG("script", DebuggerFrame_getScript, 0),

js/src/vm/Debugger.h

@@ -1155,12 +1155,15 @@ class DebuggerFrame : public NativeObject
                                             MutableHandle<DebuggerEnvironment*> result);
     static bool getIsGenerator(Handle<DebuggerFrame*> frame);
 
+    bool isLive() const;
+
   private:
     static const ClassOps classOps_;
 
     static const JSPropertySpec properties_[];
     static const JSFunctionSpec methods_[];
 
+    static MOZ_MUST_USE bool requireLive(JSContext* cx, Handle<DebuggerFrame*> frame);
     static AbstractFramePtr getReferent(Handle<DebuggerFrame*> frame);
     static MOZ_MUST_USE bool getScriptFrameIter(JSContext* cx, Handle<DebuggerFrame*> frame,
                                                 mozilla::Maybe<ScriptFrameIter>& result);
@@ -1171,6 +1174,7 @@ class DebuggerFrame : public NativeObject
     static MOZ_MUST_USE bool constructingGetter(JSContext* cx, unsigned argc, Value* vp);
     static MOZ_MUST_USE bool environmentGetter(JSContext* cx, unsigned argc, Value* vp);
     static MOZ_MUST_USE bool generatorGetter(JSContext* cx, unsigned argc, Value* vp);
+    static MOZ_MUST_USE bool liveGetter(JSContext* cx, unsigned argc, Value* vp);
 
     Debugger* owner() const;
 };