SERVER-19977 Use JS_NewArrayObject directly

Rather than creating objects with stringified integer keys, just create
them directly with JS_NewArrayObject, which can take JS::CallArgs or
JS::AutoValueVector's directly.

3 files changed, 16 insertions, 30 deletions

diff --git a/src/mongo/scripting/mozjs/jsthread.cpp b/src/mongo/scripting/mozjs/jsthread.cpp
index 2e5ea289d84..b257876afc6 100644
--- a/src/mongo/scripting/mozjs/jsthread.cpp
+++ b/src/mongo/scripting/mozjs/jsthread.cpp
@@ -88,17 +88,12 @@ public:
                 "first argument must be a function",
                 args.get(0).isObject() && JS_ObjectIsFunction(cx, args.get(0).toObjectOrNull()));
 
-        JS::RootedObject robj(cx, JS_NewPlainObject(cx));
-        ObjectWrapper wobj(cx, robj);
-        for (unsigned i = 0; i < args.length(); ++i) {
-            // 10 decimal digits for a 32 bit unsigned, then 1 for the null
-            char buf[11];
-            std::sprintf(buf, "%i", i);
-
-            wobj.setValue(buf, args.get(i));
+        JS::RootedObject robj(cx, JS_NewArrayObject(cx, args));
+        if (!robj) {
+            uasserted(ErrorCodes::JSInterpreterFailure, "Failed to JS_NewArrayObject");
         }
 
-        _sharedData->_args = wobj.toBSON();
+        _sharedData->_args = ObjectWrapper(cx, robj).toBSON();
 
         _sharedData->_stack = currentJSStackToString(cx);
 
diff --git a/src/mongo/scripting/mozjs/nativefunction.cpp b/src/mongo/scripting/mozjs/nativefunction.cpp
index 6399bb60709..45e804a6feb 100644
--- a/src/mongo/scripting/mozjs/nativefunction.cpp
+++ b/src/mongo/scripting/mozjs/nativefunction.cpp
@@ -77,20 +77,12 @@ void NativeFunctionInfo::call(JSContext* cx, JS::CallArgs args) {
         return;
     }
 
-    BSONObjBuilder bob;
-    JS::RootedObject robj(cx, JS_NewPlainObject(cx));
-    ObjectWrapper wobj(cx, robj);
-
-    for (unsigned i = 0; i < args.length(); i++) {
-        // 11 is enough here.  unsigned's are only 32 bits, and 1 << 32 is only
-        // 10 decimal digits.  +1 for the null and we're only at 11.
-        char buf[11];
-        std::sprintf(buf, "%i", i);
-
-        wobj.setValue(buf, args.get(i));
+    JS::RootedObject robj(cx, JS_NewArrayObject(cx, args));
+    if (!robj) {
+        uasserted(ErrorCodes::JSInterpreterFailure, "Failed to JS_NewArrayObject");
     }
 
-    BSONObj out = holder->_func(wobj.toBSON(), holder->_ctx);
+    BSONObj out = holder->_func(ObjectWrapper(cx, robj).toBSON(), holder->_ctx);
 
     ValueReader(cx, args.rval()).fromBSONElement(out.firstElement(), out, false);
 }
diff --git a/src/mongo/scripting/mozjs/valuereader.cpp b/src/mongo/scripting/mozjs/valuereader.cpp
index b78ed461297..292bb32f936 100644
--- a/src/mongo/scripting/mozjs/valuereader.cpp
+++ b/src/mongo/scripting/mozjs/valuereader.cpp
@@ -76,20 +76,19 @@ void ValueReader::fromBSONElement(const BSONElement& elem, const BSONObj& parent
             _value.setInt32(elem.Int());
             return;
         case mongo::Array: {
-            auto arrayPtr = JS_NewArrayObject(_context, 0);
-            uassert(ErrorCodes::JSInterpreterFailure, "Failed to JS_NewArrayObject", arrayPtr);
-            JS::RootedObject array(_context, arrayPtr);
+            JS::AutoValueVector avv(_context);
 
-            unsigned i = 0;
             BSONForEach(subElem, elem.embeddedObject()) {
-                // We use an unsigned 32 bit integer, so 10 base 10 digits and
-                // 1 null byte
-                char str[11];
-                sprintf(str, "%i", i++);
                 JS::RootedValue member(_context);
 
                 ValueReader(_context, &member).fromBSONElement(subElem, parent, readOnly);
-                ObjectWrapper(_context, array).setValue(str, member);
+                if (!avv.append(member)) {
+                    uasserted(ErrorCodes::JSInterpreterFailure, "Failed to append to JS array");
+                }
+            }
+            JS::RootedObject array(_context, JS_NewArrayObject(_context, avv));
+            if (!array) {
+                uasserted(ErrorCodes::JSInterpreterFailure, "Failed to JS_NewArrayObject");
             }
             _value.setObjectOrNull(array);
             return;