Refactor graphics interop around RAII-mapped buffers

cuda_core/cuda/core/_cpp/resource_handles.cpp

@@ -57,6 +57,7 @@ decltype(&cuLibraryUnload) p_cuLibraryUnload = nullptr;
 decltype(&cuLibraryGetKernel) p_cuLibraryGetKernel = nullptr;
 
 // GL interop pointers
+decltype(&cuGraphicsUnmapResources) p_cuGraphicsUnmapResources = nullptr;
 decltype(&cuGraphicsUnregisterResource) p_cuGraphicsUnregisterResource = nullptr;
 
 // NVRTC function pointers
@@ -569,6 +570,23 @@ DevicePtrHandle deviceptr_create_with_owner(CUdeviceptr ptr, PyObject* owner) {
     return DevicePtrHandle(box, &box->resource);
 }
 
+DevicePtrHandle deviceptr_create_mapped_graphics(
+    CUdeviceptr ptr,
+    const GraphicsResourceHandle& h_resource,
+    const StreamHandle& h_stream
+) {
+    auto box = std::shared_ptr<DevicePtrBox>(
+        new DevicePtrBox{ptr, h_stream},
+        [h_resource](DevicePtrBox* b) {
+            GILReleaseGuard gil;
+            CUgraphicsResource resource = as_cu(h_resource);
+            p_cuGraphicsUnmapResources(1, &resource, as_cu(b->h_stream));
+            delete b;
+        }
+    );
+    return DevicePtrHandle(box, &box->resource);
+}
+
 // ============================================================================
 // MemoryResource-owned Device Pointer Handles
 // ============================================================================

cuda_core/cuda/core/_cpp/resource_handles.hpp

@@ -73,6 +73,7 @@ extern decltype(&cuLibraryUnload) p_cuLibraryUnload;
 extern decltype(&cuLibraryGetKernel) p_cuLibraryGetKernel;
 
 // Graphics interop
+extern decltype(&cuGraphicsUnmapResources) p_cuGraphicsUnmapResources;
 extern decltype(&cuGraphicsUnregisterResource) p_cuGraphicsUnregisterResource;
 
 // ============================================================================
@@ -244,6 +245,16 @@ DevicePtrHandle deviceptr_create_ref(CUdeviceptr ptr);
 // If owner is nullptr, equivalent to deviceptr_create_ref.
 DevicePtrHandle deviceptr_create_with_owner(CUdeviceptr ptr, PyObject* owner);
 
+// Create a device pointer handle for a mapped graphics resource.
+// The pointer structurally depends on the provided graphics resource handle.
+// When the last reference is released, cuGraphicsUnmapResources is called on
+// the stored stream, then the graphics resource may be unregistered when its
+// own handle is released.
+DevicePtrHandle deviceptr_create_mapped_graphics(
+    CUdeviceptr ptr,
+    const GraphicsResourceHandle& h_resource,
+    const StreamHandle& h_stream);
+
 // Callback type for MemoryResource deallocation.
 // Called from the shared_ptr deleter when a handle created via
 // deviceptr_create_with_mr is destroyed.  The implementation is responsible

cuda_core/cuda/core/_graphics.pxd

@@ -9,6 +9,8 @@ cdef class GraphicsResource:
 
     cdef:
         GraphicsResourceHandle _handle
-        bint _mapped
+        object _mapped_buffer
+        object _context_manager_stream
+        object _entered_buffer
 
-    cpdef close(self)
+    cpdef close(self, stream=*)