GenArrayWaitHandle: verify input array in advance

Verify sanity of input array of dependencies in advance. Callers get the
error earlier and it also makes it easier to work with the array outside
of the main loop.

hphp/runtime/ext/asio/gen_array_wait_handle.cpp

@@ -34,12 +34,6 @@ namespace {
       exception_field = new_exception;
     }
   }
-
-  void putInvalidArgumentException(Object& exception_field) {
-    Object e(SystemLib::AllocInvalidArgumentExceptionObject(
-        "Expected dependencies to be an array of WaitHandle instances"));
-    putException(exception_field, e.get());
-  }
 }
 
 c_GenArrayWaitHandle::c_GenArrayWaitHandle(VM::Class* cb)
@@ -57,7 +51,6 @@ void c_GenArrayWaitHandle::t___construct() {
 
 Object c_GenArrayWaitHandle::ti_create(const char* cls, CArrRef dependencies) {
   Array deps = dependencies->copy();
-  Object exception;
   for (ssize_t iter_pos = deps->iter_begin();
        iter_pos != ArrayData::invalid_index;
        iter_pos = deps->iter_advance(iter_pos)) {
@@ -67,22 +60,37 @@ Object c_GenArrayWaitHandle::ti_create(const char* cls, CArrRef dependencies) {
       tvUnbox(current);
     }
 
+    if (!c_WaitHandle::fromTypedValue(current) &&
+        !IS_NULL_TYPE(current->m_type)) {
+      Object e(SystemLib::AllocInvalidArgumentExceptionObject(
+        "Expected dependencies to be an array of WaitHandle instances"));
+      throw e;
+    }
+  }
+
+  Object exception;
+  for (ssize_t iter_pos = deps->iter_begin();
+       iter_pos != ArrayData::invalid_index;
+       iter_pos = deps->iter_advance(iter_pos)) {
+
+    TypedValue* current = deps->nvGetValueRef(iter_pos);
     if (IS_NULL_TYPE(current->m_type)) {
       // {uninit,null} yields null
       tvWriteNull(current);
       continue;
     }
 
-    c_WaitHandle* child = c_WaitHandle::fromTypedValue(current);
-    if (UNLIKELY(!child)) {
-      putInvalidArgumentException(exception);
-    } else if (child->isSucceeded()) {
+    assert(current->m_type == KindOfObject);
+    assert(dynamic_cast<c_WaitHandle*>(current->m_data.pobj));
+    auto child = static_cast<c_WaitHandle*>(current->m_data.pobj);
+
+    if (child->isSucceeded()) {
       tvSetIgnoreRef(child->getResult(), current);
     } else if (child->isFailed()) {
       putException(exception, child->getException());
     } else {
-      c_WaitableWaitHandle* child_wh =
-        static_cast<c_WaitableWaitHandle*>(child);
+      assert(dynamic_cast<c_WaitableWaitHandle*>(child));
+      auto child_wh = static_cast<c_WaitableWaitHandle*>(child);
 
       c_GenArrayWaitHandle* my_wh = NEWOBJ(c_GenArrayWaitHandle)();
       my_wh->initialize(exception, deps, iter_pos, child_wh);
@@ -116,26 +124,23 @@ void c_GenArrayWaitHandle::onUnblocked() {
        m_iterPos = m_deps->iter_advance(m_iterPos)) {
 
     TypedValue* current = m_deps->nvGetValueRef(m_iterPos);
-    if (UNLIKELY(current->m_type == KindOfRef)) {
-      tvUnbox(current);
-    }
-
     if (IS_NULL_TYPE(current->m_type)) {
       // {uninit,null} yields null
       tvWriteNull(current);
       continue;
     }
 
-    c_WaitHandle* child = c_WaitHandle::fromTypedValue(current);
-    if (UNLIKELY(!child)) {
-      putInvalidArgumentException(m_exception);
-    } else if (child->isSucceeded()) {
+    assert(current->m_type == KindOfObject);
+    assert(dynamic_cast<c_WaitHandle*>(current->m_data.pobj));
+    auto child = static_cast<c_WaitHandle*>(current->m_data.pobj);
+
+    if (child->isSucceeded()) {
       tvSetIgnoreRef(child->getResult(), current);
     } else if (child->isFailed()) {
       putException(m_exception, child->getException());
     } else {
-      c_WaitableWaitHandle* child_wh =
-        static_cast<c_WaitableWaitHandle*>(child);
+      assert(dynamic_cast<c_WaitableWaitHandle*>(child));
+      auto child_wh = static_cast<c_WaitableWaitHandle*>(child);
 
       try {
         blockOn(child_wh);