fix mismatched issue if using zero_allocate

rclcpp/include/rclcpp/allocator/allocator_common.hpp

@@ -15,6 +15,7 @@
 #ifndef RCLCPP__ALLOCATOR__ALLOCATOR_COMMON_HPP_
 #define RCLCPP__ALLOCATOR__ALLOCATOR_COMMON_HPP_
 
+#include <cstring>
 #include <memory>
 
 #include "rcl/allocator.h"
@@ -39,6 +40,22 @@ void * retyped_allocate(size_t size, void * untyped_allocator)
   return std::allocator_traits<Alloc>::allocate(*typed_allocator, size);
 }
 
+template<typename Alloc>
+void * retyped_zero_allocate(size_t number_of_elem, size_t size_of_elem, void * untyped_allocator)
+{
+  auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
+  if (!typed_allocator) {
+    throw std::runtime_error("Received incorrect allocator type");
+  }
+  size_t size = number_of_elem * size_of_elem;
+  void * allocated_memory =
+    std::allocator_traits<Alloc>::allocate(*typed_allocator, size);
+  if (allocated_memory) {
+    std::memset(allocated_memory, 0, size);
+  }
+  return allocated_memory;
+}
+
 template<typename T, typename Alloc>
 void retyped_deallocate(void * untyped_pointer, void * untyped_allocator)
 {
@@ -73,6 +90,7 @@ rcl_allocator_t get_rcl_allocator(Alloc & allocator)
   rcl_allocator_t rcl_allocator = rcl_get_default_allocator();
 #ifndef _WIN32
   rcl_allocator.allocate = &retyped_allocate<Alloc>;
+  rcl_allocator.zero_allocate = &retyped_zero_allocate<Alloc>;
   rcl_allocator.deallocate = &retyped_deallocate<T, Alloc>;
   rcl_allocator.reallocate = &retyped_reallocate<T, Alloc>;
   rcl_allocator.state = &allocator;

rclcpp/test/rclcpp/allocator/test_allocator_common.cpp

@@ -51,6 +51,53 @@ TEST(TestAllocatorCommon, retyped_allocate) {
   EXPECT_NO_THROW(code2());
 }
 
+TEST(TestAllocatorCommon, retyped_zero_allocate_basic) {
+  std::allocator<int> allocator;
+  void * untyped_allocator = &allocator;
+  void * allocated_mem =
+    rclcpp::allocator::retyped_zero_allocate<std::allocator<char>>(20u, 1u, untyped_allocator);
+  ASSERT_TRUE(nullptr != allocated_mem);
+
+  auto code = [&untyped_allocator, allocated_mem]() {
+      rclcpp::allocator::retyped_deallocate<char, std::allocator<char>>(
+        allocated_mem, untyped_allocator);
+    };
+  EXPECT_NO_THROW(code());
+}
+
+TEST(TestAllocatorCommon, retyped_zero_allocate) {
+  std::allocator<int> allocator;
+  void * untyped_allocator = &allocator;
+  void * allocated_mem =
+    rclcpp::allocator::retyped_zero_allocate<std::allocator<char>>(20u, 1u, untyped_allocator);
+  // The more natural check here is ASSERT_NE(nullptr, ptr), but clang static
+  // analysis throws a false-positive memory leak warning.  Use ASSERT_TRUE instead.
+  ASSERT_TRUE(nullptr != allocated_mem);
+
+  auto code = [&untyped_allocator, allocated_mem]() {
+      rclcpp::allocator::retyped_deallocate<int, std::allocator<int>>(
+        allocated_mem, untyped_allocator);
+    };
+  EXPECT_NO_THROW(code());
+
+  allocated_mem = allocator.allocate(1);
+  // The more natural check here is ASSERT_NE(nullptr, ptr), but clang static
+  // analysis throws a false-positive memory leak warning.  Use ASSERT_TRUE instead.
+  ASSERT_TRUE(nullptr != allocated_mem);
+  void * reallocated_mem =
+    rclcpp::allocator::retyped_reallocate<int, std::allocator<int>>(
+    allocated_mem, 2u, untyped_allocator);
+  // The more natural check here is ASSERT_NE(nullptr, ptr), but clang static
+  // analysis throws a false-positive memory leak warning.  Use ASSERT_TRUE instead.
+  ASSERT_TRUE(nullptr != reallocated_mem);
+
+  auto code2 = [&untyped_allocator, reallocated_mem]() {
+      rclcpp::allocator::retyped_deallocate<int, std::allocator<int>>(
+        reallocated_mem, untyped_allocator);
+    };
+  EXPECT_NO_THROW(code2());
+}
+
 TEST(TestAllocatorCommon, get_rcl_allocator) {
   std::allocator<int> allocator;
   auto rcl_allocator = rclcpp::allocator::get_rcl_allocator<int>(allocator);