Fix: make Filter compute take self instead of &self (#5248)

Signed-off-by: Connor Tsui <connor.tsui20@gmail.com>

Author: connortsui20

vortex-compute/src/filter/bitbuffer.rs

@@ -10,12 +10,14 @@ use crate::filter::Filter;
 // TODO(ngates): we need more experimentation to determine the best threshold here.
 const FILTER_SLICES_DENSITY_THRESHOLD: f64 = 0.8;
 
-impl Filter for BitBuffer {
-    fn filter(&self, mask: &Mask) -> Self {
+impl Filter for &BitBuffer {
+    type Output = BitBuffer;
+
+    fn filter(self, mask: &Mask) -> BitBuffer {
         assert_eq!(mask.len(), self.len());
         match mask {
             Mask::AllTrue(_) => self.clone(),
-            Mask::AllFalse(_) => Self::empty(),
+            Mask::AllFalse(_) => BitBuffer::empty(),
             Mask::Values(v) => match v.threshold_iter(FILTER_SLICES_DENSITY_THRESHOLD) {
                 MaskIter::Indices(indices) => filter_indices(self, indices),
                 MaskIter::Slices(slices) => filter_slices(self, mask.true_count(), slices),

vortex-compute/src/filter/bool.rs

@@ -7,14 +7,16 @@ use vortex_vector::bool::BoolVector;
 
 use crate::filter::Filter;
 
-impl Filter for BoolVector {
-    fn filter(&self, mask: &Mask) -> Self {
+impl Filter for &BoolVector {
+    type Output = BoolVector;
+
+    fn filter(self, mask: &Mask) -> BoolVector {
         let filtered_bits = self.bits().filter(mask);
         let filtered_validity = self.validity().filter(mask);
 
         // SAFETY: We filter the bits and validity with the same mask, and since they came from an
         // existing and valid `BoolVector`, we know that the filtered output must have the same
         // length.
-        unsafe { Self::new_unchecked(filtered_bits, filtered_validity) }
+        unsafe { BoolVector::new_unchecked(filtered_bits, filtered_validity) }
     }
 }

vortex-compute/src/filter/buffer.rs

@@ -9,12 +9,14 @@ use crate::filter::Filter;
 // This is modeled after the constant with the equivalent name in arrow-rs.
 const FILTER_SLICES_SELECTIVITY_THRESHOLD: f64 = 0.8;
 
-impl<T: Copy> Filter for Buffer<T> {
-    fn filter(&self, mask: &Mask) -> Self {
+impl<T: Copy> Filter for &Buffer<T> {
+    type Output = Buffer<T>;
+
+    fn filter(self, mask: &Mask) -> Buffer<T> {
         assert_eq!(mask.len(), self.len());
         match mask {
             Mask::AllTrue(_) => self.clone(),
-            Mask::AllFalse(_) => Self::empty(),
+            Mask::AllFalse(_) => Buffer::empty(),
             Mask::Values(v) => match v.threshold_iter(FILTER_SLICES_SELECTIVITY_THRESHOLD) {
                 MaskIter::Indices(indices) => filter_indices(self.as_slice(), indices),
                 MaskIter::Slices(slices) => {

vortex-compute/src/filter/mask.rs

@@ -5,16 +5,18 @@ use vortex_mask::Mask;
 
 use crate::filter::Filter;
 
-impl Filter for Mask {
-    fn filter(&self, mask: &Mask) -> Self {
+impl Filter for &Mask {
+    type Output = Mask;
+
+    fn filter(self, mask: &Mask) -> Mask {
         assert_eq!(self.len(), mask.len());
 
         match (self, mask) {
             (Mask::AllTrue(_), _) => Mask::AllTrue(mask.true_count()),
             (Mask::AllFalse(_), _) => Mask::AllFalse(mask.true_count()),
 
             (Mask::Values(_), Mask::AllTrue(_)) => self.clone(),
-            (Mask::Values(_), Mask::AllFalse(_)) => Self::new_true(0),
+            (Mask::Values(_), Mask::AllFalse(_)) => Mask::new_true(0),
             (Mask::Values(v1), Mask::Values(_)) => Mask::from(v1.bit_buffer().filter(mask)),
         }
     }

vortex-compute/src/filter/mod.rs

@@ -12,12 +12,15 @@ use vortex_mask::Mask;
 
 /// Function for filtering based on a selection mask.
 pub trait Filter {
+    /// The result type after performing the operation.
+    type Output;
+
     /// Filters the vector using the provided mask, returning a new value.
     ///
     /// The result value will have length equal to the true count of the provided mask.
     ///
     /// # Panics
     ///
     /// If the length of the mask does not equal the length of the value being filtered.
-    fn filter(&self, mask: &Mask) -> Self;
+    fn filter(self, mask: &Mask) -> Self::Output;
 }