dawn.node: Detach buffer mappings on GPUBuffer.destroy.

Bug: dawn:1123
Change-Id: I662c60346a5c57030e932d636ea2f9d8519c5fc8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86142
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/dawn/node/binding/GPUBuffer.cpp

@@ -139,23 +139,32 @@ namespace wgpu::binding {
     }
 
     void GPUBuffer::unmap(Napi::Env env) {
+        buffer_.Unmap();
+
+        if (state_ != State::Destroyed && state_ != State::Unmapped) {
+            DetachMappings();
+            state_ = State::Unmapped;
+        }
+    }
+
+    void GPUBuffer::destroy(Napi::Env) {
         if (state_ == State::Destroyed) {
-            device_.InjectError(wgpu::ErrorType::Validation,
-                                "unmap() called on a destroyed buffer");
             return;
         }
 
+        if (state_ != State::Unmapped) {
+            DetachMappings();
+        }
+
+        buffer_.Destroy();
+        state_ = State::Destroyed;
+    }
+
+    void GPUBuffer::DetachMappings() {
         for (auto& mapping : mapped_) {
             mapping.buffer.Value().Detach();
         }
         mapped_.clear();
-        buffer_.Unmap();
-        state_ = State::Unmapped;
-    }
-
-    void GPUBuffer::destroy(Napi::Env) {
-        buffer_.Destroy();
-        state_ = State::Destroyed;
     }
 
     std::variant<std::string, interop::UndefinedType> GPUBuffer::getLabel(Napi::Env) {

src/dawn/node/binding/GPUBuffer.h

@@ -55,6 +55,8 @@ namespace wgpu::binding {
         void setLabel(Napi::Env, std::variant<std::string, interop::UndefinedType> value) override;
 
       private:
+        void DetachMappings();
+
         struct Mapping {
             uint64_t start;
             uint64_t end;