From 745bebcbb5063200b7905279d43947bb1daa9140 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvarkus@gmail.com>
Date: Thu, 13 Jun 2019 11:22:54 -0400
Subject: [PATCH] Move buffer state tracking into a module, add unit tests

---
 wgpu-native/src/track/buffer.rs | 99 +++++++++++++++++++++++++++++++++
 wgpu-native/src/track/mod.rs    | 78 +-------------------------
 2 files changed, 102 insertions(+), 75 deletions(-)
 create mode 100644 wgpu-native/src/track/buffer.rs

diff --git a/wgpu-native/src/track/buffer.rs b/wgpu-native/src/track/buffer.rs
new file mode 100644
index 0000000000..f22a371e37
--- /dev/null
+++ b/wgpu-native/src/track/buffer.rs
@@ -0,0 +1,99 @@
+use crate::{
+    conv,
+    resource::BufferUsage,
+    BufferId,
+};
+use super::{PendingTransition, ResourceState, Stitch, Unit};
+use std::ops::Range;
+
+//TODO: store `hal::buffer::State` here to avoid extra conversions
+pub type BufferState = Unit<BufferUsage>;
+
+impl PendingTransition<BufferState> {
+    pub fn to_states(&self) -> Range<hal::buffer::State> {
+        conv::map_buffer_state(self.usage.start) ..
+        conv::map_buffer_state(self.usage.end)
+    }
+}
+
+impl Default for BufferState {
+    fn default() -> Self {
+        BufferState {
+            init: BufferUsage::empty(),
+            last: BufferUsage::empty(),
+        }
+    }
+}
+
+impl ResourceState for BufferState {
+    type Id = BufferId;
+    type Selector = ();
+    type Usage = BufferUsage;
+
+    fn query(
+        &self,
+        _selector: Self::Selector,
+    ) -> Option<Self::Usage> {
+        Some(self.last)
+    }
+
+    fn change(
+        &mut self,
+        id: Self::Id,
+        _selector: Self::Selector,
+        usage: Self::Usage,
+        output: Option<&mut Vec<PendingTransition<Self>>>,
+    ) -> Result<(), PendingTransition<Self>> {
+        let old = self.last;
+        if usage != old {
+            let pending = PendingTransition {
+                id,
+                selector: (),
+                usage: old .. usage,
+            };
+            self.last = match output {
+                Some(transitions) => {
+                    transitions.push(pending);
+                    usage
+                }
+                None =>  {
+                    if !old.is_empty() && BufferUsage::WRITE_ALL.intersects(old | usage) {
+                        return Err(pending);
+                    }
+                    old | usage
+                }
+            };
+        }
+        Ok(())
+    }
+
+    fn merge(
+        &mut self,
+        id: Self::Id,
+        other: &Self,
+        stitch: Stitch,
+        output: Option<&mut Vec<PendingTransition<Self>>>,
+    ) -> Result<(), PendingTransition<Self>> {
+        let usage = other.select(stitch);
+        self.change(id, (), usage, output)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::TypedId;
+    use super::*;
+
+    #[test]
+    fn change() {
+        let mut bs = Unit {
+            init: BufferUsage::INDEX,
+            last: BufferUsage::STORAGE,
+        };
+        let id = TypedId::new(0, 0);
+        assert!(bs.change(id, (), BufferUsage::VERTEX, None).is_err());
+        bs.change(id, (), BufferUsage::VERTEX, Some(&mut Vec::new())).unwrap();
+        bs.change(id, (), BufferUsage::INDEX, None).unwrap();
+        assert_eq!(bs.last, BufferUsage::VERTEX | BufferUsage::INDEX);
+    }
+}
diff --git a/wgpu-native/src/track/mod.rs b/wgpu-native/src/track/mod.rs
index 9acbcca85e..842fef8104 100644
--- a/wgpu-native/src/track/mod.rs
+++ b/wgpu-native/src/track/mod.rs
@@ -1,11 +1,11 @@
+mod buffer;
 mod range;
 
 use crate::{
     conv,
     device::MAX_MIP_LEVELS,
     hub::Storage,
-    resource::{BufferUsage, TextureUsage},
-    BufferId,
+    resource::{TextureUsage},
     Epoch,
     Index,
     RefCount,
@@ -26,6 +26,7 @@ use std::{
     vec::Drain,
 };
 
+use buffer::BufferState;
 use range::RangedStates;
 
 
@@ -289,79 +290,6 @@ impl<S: ResourceState> ResourceTracker<S> {
     }
 }
 
-//TODO: store `hal::buffer::State` here to avoid extra conversions
-pub type BufferState = Unit<BufferUsage>;
-
-impl PendingTransition<BufferState> {
-    pub fn to_states(&self) -> Range<hal::buffer::State> {
-        conv::map_buffer_state(self.usage.start) ..
-        conv::map_buffer_state(self.usage.end)
-    }
-}
-
-impl Default for BufferState {
-    fn default() -> Self {
-        BufferState {
-            init: BufferUsage::empty(),
-            last: BufferUsage::empty(),
-        }
-    }
-}
-
-impl ResourceState for BufferState {
-    type Id = BufferId;
-    type Selector = ();
-    type Usage = BufferUsage;
-
-    fn query(
-        &self,
-        _selector: Self::Selector,
-    ) -> Option<Self::Usage> {
-        Some(self.last)
-    }
-
-    fn change(
-        &mut self,
-        id: Self::Id,
-        _selector: Self::Selector,
-        usage: Self::Usage,
-        output: Option<&mut Vec<PendingTransition<Self>>>,
-    ) -> Result<(), PendingTransition<Self>> {
-        let old = self.last;
-        if usage != old {
-            let pending = PendingTransition {
-                id,
-                selector: (),
-                usage: old .. usage,
-            };
-            self.last = match output {
-                Some(transitions) => {
-                    transitions.push(pending);
-                    usage
-                }
-                None =>  {
-                    if !old.is_empty() && BufferUsage::WRITE_ALL.intersects(old | usage) {
-                        return Err(pending);
-                    }
-                    old | usage
-                }
-            };
-        }
-        Ok(())
-    }
-
-    fn merge(
-        &mut self,
-        id: Self::Id,
-        other: &Self,
-        stitch: Stitch,
-        output: Option<&mut Vec<PendingTransition<Self>>>,
-    ) -> Result<(), PendingTransition<Self>> {
-        let usage = other.select(stitch);
-        self.change(id, (), usage, output)
-    }
-}
-
 
 type PlaneStates<T> = RangedStates<hal::image::Layer, T>;