src: port memory-tracking allocator from QUIC repo

This implements a memory-tracking allocator that can be used to
provide memory allocation facilities to several thread-safe C
libraries, including nghttp2, nghttp3, ngtcp3 and uvwasi.

Refs: https://github.com/nodejs/quic/blob/34ee0bc96f804c73cb22b2945a1a78f780938492/src/node_mem.h
Co-authored-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/30745
Refs: https://github.com/nodejs/quic/pull/126
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/src/node_mem.h b/src/node_mem.h
new file mode 100644
index 00000000000..0d3388ad476
--- /dev/null
+++ b/src/node_mem.h
@@ -0,0 +1,41 @@
+#ifndef SRC_NODE_MEM_H_
+#define SRC_NODE_MEM_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include <cstddef>
+
+namespace node {
+namespace mem {
+
+// Both ngtcp2 and nghttp2 allow custom allocators that
+// follow exactly the same structure and behavior, but
+// use different struct names. To allow for code re-use,
+// the NgLibMemoryManager template class can be used for both.
+
+template <typename Class, typename AllocatorStructName>
+class NgLibMemoryManager {
+ public:
+  // Class needs to provide these methods:
+  // void CheckAllocatedSize(size_t previous_size) const;
+  // void IncreaseAllocatedSize(size_t size);
+  // void DecreaseAllocatedSize(size_t size);
+  // Environment* env() const;
+
+  AllocatorStructName MakeAllocator();
+
+  void StopTrackingMemory(void* ptr);
+
+ private:
+  static void* ReallocImpl(void* ptr, size_t size, void* user_data);
+  static void* MallocImpl(size_t size, void* user_data);
+  static void FreeImpl(void* ptr, void* user_data);
+  static void* CallocImpl(size_t nmemb, size_t size, void* user_data);
+};
+
+}  // namespace mem
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_NODE_MEM_H_