Change signature of array_list::pop().

src/rt/rust_task.cpp

@@ -400,7 +400,8 @@ rust_task::notify_tasks_waiting_to_join() {
     while (tasks_waiting_to_join.is_empty() == false) {
         log(rust_log::TASK, "notify_tasks_waiting_to_join: %d",
             tasks_waiting_to_join.size());
-        maybe_proxy<rust_task> *waiting_task = tasks_waiting_to_join.pop();
+        maybe_proxy<rust_task> *waiting_task;
+        tasks_waiting_to_join.pop(&waiting_task);
         if (waiting_task->is_proxy()) {
             notify_message::send(notify_message::WAKEUP, "wakeup",
                                  this, waiting_task->as_proxy());

src/rt/util/array_list.h

@@ -15,7 +15,7 @@ public:
     size_t size();
     int32_t append(T value);
     int32_t push(T value);
-    T pop();
+    bool pop(T *value);
     bool replace(T old_value, T new_value);
     int32_t index_of(T value);
     bool is_empty();
@@ -54,10 +54,17 @@ array_list<T>::push(T value) {
     return _size - 1;
 }
 
-template<typename T> T
-array_list<T>::pop() {
-    T value = _data[-- _size];
-    return value;
+template<typename T> bool
+array_list<T>::pop(T *value) {
+    if (_size == 0) {
+        return false;
+    }
+    if (value != NULL) {
+        *value = _data[-- _size];
+    } else {
+        -- _size;
+    }
+    return true;
 }
 
 /**

src/rt/util/indexed_list.h

@@ -24,6 +24,7 @@ template<typename T> class indexed_list {
 public:
     indexed_list(memory_region &region) : region(region) {}
     virtual int32_t append(T *value);
+    virtual bool pop(T **value);
     virtual size_t length() {
         return list.size();
     }
@@ -48,7 +49,8 @@ indexed_list<T>::remove(T *value) {
     assert (value->list_index >= 0);
     assert (value->list_index < (int32_t)list.size());
     int32_t removeIndex = value->list_index;
-    T *last = list.pop();
+    T *last;
+    list.pop(&last);
     if (last->list_index == removeIndex) {
         last->list_index = -1;
         return removeIndex;
@@ -60,6 +62,11 @@ indexed_list<T>::remove(T *value) {
     }
 }
 
+template<typename T> bool
+indexed_list<T>::pop(T **value) {
+    return list.pop(value);
+}
+
 template <typename T> T *
 indexed_list<T>::operator[](int32_t index) {
     T *value = list[index];