Use Pin for keep-alive variables

Traverse-Research · Apr 23, 2024 · c1522a9 · c1522a9
1 parent d784ef6
commit c1522a9
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Showing 2 changed files with 15 additions and 19 deletions.
diff --git a/src/ispc/mod.rs b/src/ispc/mod.rs
@@ -2,7 +2,7 @@
 
 use ispc_rt::ispc_module;
 
-use std::rc::Rc;
+use std::{pin::Pin, rc::Rc};
 
 use crate::CachedWeight;
 pub use downsample_ispc::*;
@@ -25,10 +25,10 @@ pub(crate) struct WeightCollection {
     ispc_representation: downsample_ispc::WeightCollection,
 
     // Keep these because we need to keep them in memory
-    _starts: Vec<u32>,
-    _weight_counts: Vec<u32>,
-    _weights: Vec<Rc<Vec<f32>>>,
-    _weights_ptrs: Vec<*const f32>,
+    _starts: Pin<Vec<u32>>,
+    _weight_counts: Pin<Vec<u32>>,
+    _weights: Pin<Vec<Rc<Vec<f32>>>>,
+    _weights_ptrs: Pin<Vec<*const f32>>,
 }
 
 impl WeightCollection {
@@ -51,10 +51,10 @@ impl WeightCollection {
                 weight_counts: counts.as_ptr(),
                 values: weights_ptrs.as_ptr(),
             },
-            _starts: starts,
-            _weight_counts: counts,
-            _weights: weights,
-            _weights_ptrs: weights_ptrs,
+            _starts: Pin::new(starts),
+            _weight_counts: Pin::new(counts),
+            _weights: Pin::new(weights),
+            _weights_ptrs: Pin::new(weights_ptrs),
         })
     }
 
@@ -66,8 +66,9 @@ impl WeightCollection {
 pub(crate) struct Weights {
     ispc_representation: SampleWeights,
 
-    _horizontal_weights: Rc<WeightCollection>,
-    _vertical_weights: Rc<WeightCollection>,
+    // Need to be kept alive because the ispc_representation holds pointers to them
+    _horizontal_weights: Pin<Rc<WeightCollection>>,
+    _vertical_weights: Pin<Rc<WeightCollection>>,
 }
 
 impl Weights {
@@ -80,8 +81,8 @@ impl Weights {
                 vertical_weights: vertical_weights.ispc_representation(),
                 horizontal_weights: horizontal_weights.ispc_representation(),
             },
-            _vertical_weights: vertical_weights,
-            _horizontal_weights: horizontal_weights,
+            _vertical_weights: Pin::new(vertical_weights),
+            _horizontal_weights: Pin::new(horizontal_weights),
         }
     }
 

diff --git a/src/lib.rs b/src/lib.rs
@@ -73,7 +73,7 @@ impl NormalMapFormat {
 }
 
 impl From<NormalMapFormat> for ispc::NormalMapFormat {
-    fn from(value: NormalMapFormat) -> i32 {
+    fn from(value: NormalMapFormat) -> ispc::NormalMapFormat {
         match value {
             NormalMapFormat::R8g8b8 => ispc::NormalMapFormat_R8g8b8,
             NormalMapFormat::R8g8TangentSpaceReconstructedZ => {
@@ -257,11 +257,6 @@ fn precompute_lanczos_weights(
     };
 
     ispc::Weights::new(width_weights, height_weights)
-
-    // ispc::SampleWeights {
-    //     vertical_weights: height_weights.ispc_representation(),
-    //     horizontal_weights: width_weights.ispc_representation(),
-    // }
 }
 
 /// Version of [downsample] which allows for a custom filter scale, thus trading between speed and final image quality.