3 files changed, 21 insertions, 13 deletions
diff --git a/include/cru/platform/exception.hpp b/include/cru/platform/exception.hpp
index 6dae08c5..b1e505e0 100644
--- a/include/cru/platform/exception.hpp
+++ b/include/cru/platform/exception.hpp
@@ -6,6 +6,15 @@
 namespace cru::platform {
 class PlatformException : public std::runtime_error {
  public:
-  using runtime_error::runtime_error; // inherent constructors
+  using runtime_error::runtime_error;  // inherit constructors
+};
+
+// This exception is throwed when a resource has been disposed and not usable
+// again.
+// For example, calling Build twice on a GeometryBuild will lead to this
+// exception.
+class ReuseException : public std::runtime_error {
+ public:
+  using runtime_error::runtime_error;  // inherit constructors
 };
 }  // namespace cru::platform
diff --git a/include/cru/win/graph/direct/geometry.hpp b/include/cru/win/graph/direct/geometry.hpp
index f40db7af..1ee60247 100644
--- a/include/cru/win/graph/direct/geometry.hpp
+++ b/include/cru/win/graph/direct/geometry.hpp
@@ -3,6 +3,7 @@
 #include "direct_factory.hpp"
 #include "platform_id.hpp"
 
+#include "cru/platform/exception.hpp"
 #include "cru/platform/graph/geometry.hpp"
 
 namespace cru::platform::graph::win::direct {
@@ -16,7 +17,7 @@ class D2DGeometryBuilder : public GeometryBuilder {
   D2DGeometryBuilder(D2DGeometryBuilder&& other) = delete;
   D2DGeometryBuilder& operator=(D2DGeometryBuilder&& other) = delete;
 
-  ~D2DGeometryBuilder() override;
+  ~D2DGeometryBuilder() override = default;
 
   CRU_PLATFORMID_IMPLEMENT_DIRECT
 
@@ -31,6 +32,10 @@ class D2DGeometryBuilder : public GeometryBuilder {
 
  private:
   bool IsValid() { return geometry_ != nullptr; }
+  void CheckValidation() {
+    if (!IsValid())
+      throw ReuseException("The geometry builder is already disposed.");
+  }
 
  private:
   Microsoft::WRL::ComPtr<ID2D1PathGeometry> geometry_;
diff --git a/src/win/graph/direct/geometry.cpp b/src/win/graph/direct/geometry.cpp
index 6b827906..470addee 100644
--- a/src/win/graph/direct/geometry.cpp
+++ b/src/win/graph/direct/geometry.cpp
@@ -12,37 +12,31 @@ D2DGeometryBuilder::D2DGeometryBuilder(IDirectFactory* factory) {
   ThrowIfFailed(geometry_->Open(&geometry_sink_));
 }
 
-D2DGeometryBuilder::~D2DGeometryBuilder() {
-  if (geometry_sink_) {
-    ThrowIfFailed(geometry_sink_->Close());
-  }
-}
-
 void D2DGeometryBuilder::BeginFigure(const Point& point) {
-  assert(IsValid());
+  CheckValidation();
   geometry_sink_->BeginFigure(Convert(point), D2D1_FIGURE_BEGIN_FILLED);
 }
 
 void D2DGeometryBuilder::LineTo(const Point& point) {
-  assert(IsValid());
+  CheckValidation();
   geometry_sink_->AddLine(Convert(point));
 }
 
 void D2DGeometryBuilder::QuadraticBezierTo(const Point& control_point,
                                            const Point& end_point) {
-  assert(IsValid());
+  CheckValidation();
   geometry_sink_->AddQuadraticBezier(
       D2D1::QuadraticBezierSegment(Convert(control_point), Convert(end_point)));
 }
 
 void D2DGeometryBuilder::CloseFigure(bool close) {
-  assert(IsValid());
+  CheckValidation();
   geometry_sink_->EndFigure(close ? D2D1_FIGURE_END_CLOSED
                                   : D2D1_FIGURE_END_OPEN);
 }
 
 Geometry* D2DGeometryBuilder::Build() {
-  assert(IsValid());
+  CheckValidation();
   ThrowIfFailed(geometry_sink_->Close());
   geometry_sink_ = nullptr;
   const auto geometry = new D2DGeometry(std::move(geometry_));