Introduce new Chunk iteration APIs (#8553)

* Way more ergonomic
* Same performance
* Less code
* Support for structs!
* Basis for new upcoming codegen'd deserialization APIs (...at some
point)

crates/store/re_chunk/src/lib.rs

@@ -28,7 +28,9 @@ pub use self::builder::{ChunkBuilder, TimeColumnBuilder};
 pub use self::chunk::{Chunk, ChunkComponents, ChunkError, ChunkResult, TimeColumn};
 pub use self::helpers::{ChunkShared, UnitChunkShared};
 pub use self::id::{ChunkId, RowId};
-pub use self::iter::{ChunkComponentIter, ChunkComponentIterItem, ChunkIndicesIter};
+pub use self::iter::{
+    ChunkComponentIter, ChunkComponentIterItem, ChunkComponentSlicer, ChunkIndicesIter,
+};
 pub use self::latest_at::LatestAtQuery;
 pub use self::range::{RangeQuery, RangeQueryOptions};
 pub use self::transport::TransportChunk;

crates/store/re_grpc_client/src/lib.rs

@@ -480,7 +480,7 @@ async fn stream_catalog_async(
             )))?;
 
         let recording_uri_arrays: Vec<Box<dyn Arrow2Array>> = chunk
-            .iter_string(&"id".into())
+            .iter_slices::<String>("id".into())
             .map(|id| {
                 let rec_id = &id[0]; // each component batch is of length 1 i.e. single 'id' value
 

crates/store/re_query/examples/range.rs

@@ -65,7 +65,7 @@ fn main() -> anyhow::Result<()> {
         .flat_map(|chunk| {
             izip!(
                 chunk.iter_component_indices(&query.timeline(), &MyColor::name()),
-                chunk.iter_primitive::<u32>(&MyColor::name()),
+                chunk.iter_slices::<u32>(MyColor::name()),
             )
         });
 

crates/store/re_query/tests/range.rs

@@ -1089,7 +1089,7 @@ fn query_and_compare(
             .flat_map(|chunk| {
                 itertools::izip!(
                     chunk.iter_component_indices(&query.timeline(), &MyColor::name()),
-                    chunk.iter_primitive::<u32>(&MyColor::name()),
+                    chunk.iter_slices::<u32>(MyColor::name()),
                 )
             })
             .collect_vec();

crates/store/re_types_core/src/lib.rs

@@ -345,7 +345,7 @@ pub mod external {
 ///
 #[macro_export]
 macro_rules! static_assert_struct_has_fields {
-    ($strct:ty, $($field:ident: $field_typ:ty),+) => {
+    ($strct:ty, $($field:ident: $field_typ:ty),+ $(,)?) => {
         const _: fn(&$strct) = |s: &$strct| {
             $(let _: &$field_typ = &s.$field;)+
         };

crates/viewer/re_view/src/results_ext.rs

@@ -239,9 +239,8 @@ pub trait RangeResultsExt {
     /// Returns a zero-copy iterator over all the results for the given `(timeline, component)` pair.
     ///
     /// Call one of the following methods on the returned [`HybridResultsChunkIter`]:
-    /// * [`HybridResultsChunkIter::primitive`]
-    /// * [`HybridResultsChunkIter::primitive_array`]
-    /// * [`HybridResultsChunkIter::string`]
+    /// * [`HybridResultsChunkIter::slice`]
+    /// * [`HybridResultsChunkIter::slice_from_struct_field`]
     fn iter_as(
         &self,
         timeline: Timeline,
@@ -408,7 +407,7 @@ impl RangeResultsExt for HybridResults<'_> {
 // ---
 
 use re_chunk::{ChunkComponentIterItem, RowId, TimeInt, Timeline};
-use re_chunk_store::external::{re_chunk, re_chunk::external::arrow2};
+use re_chunk_store::external::re_chunk;
 
 /// The iterator type backing [`HybridResults::iter_as`].
 pub struct HybridResultsChunkIter<'a> {
@@ -523,4 +522,33 @@ impl<'a> HybridResultsChunkIter<'a> {
             )
         })
     }
+
+    /// Iterate as indexed, sliced, deserialized component batches.
+    ///
+    /// See [`Chunk::iter_slices`] for more information.
+    pub fn slice<S: 'a + re_chunk::ChunkComponentSlicer>(
+        &'a self,
+    ) -> impl Iterator<Item = ((TimeInt, RowId), S::Item<'a>)> + 'a {
+        self.chunks.iter().flat_map(|chunk| {
+            itertools::izip!(
+                chunk.iter_component_indices(&self.timeline, &self.component_name),
+                chunk.iter_slices::<S>(self.component_name)
+            )
+        })
+    }
+
+    /// Iterate as indexed, sliced, deserialized component batches for a specific struct field.
+    ///
+    /// See [`Chunk::iter_slices_from_struct_field`] for more information.
+    pub fn slice_from_struct_field<S: 'a + re_chunk::ChunkComponentSlicer>(
+        &'a self,
+        field_name: &'a str,
+    ) -> impl Iterator<Item = ((TimeInt, RowId), S::Item<'a>)> + 'a {
+        self.chunks.iter().flat_map(|chunk| {
+            itertools::izip!(
+                chunk.iter_component_indices(&self.timeline, &self.component_name),
+                chunk.iter_slices_from_struct_field::<S>(self.component_name, field_name)
+            )
+        })
+    }
 }

crates/viewer/re_view_spatial/src/visualizers/utilities/entity_iterator.rs

@@ -130,7 +130,7 @@ where
 // ---
 
 use re_chunk::{Chunk, ChunkComponentIterItem, ComponentName, RowId};
-use re_chunk_store::external::{re_chunk, re_chunk::external::arrow2};
+use re_chunk_store::external::re_chunk;
 
 /// Iterate `chunks` as indexed deserialized batches.
 ///
@@ -239,3 +239,19 @@ pub fn iter_buffer<'a, T: arrow::datatypes::ArrowNativeType + arrow2::types::Nat
         )
     })
 }
+
+/// Iterate `chunks` as indexed primitives.
+///
+/// See [`Chunk::iter_slices`] for more information.
+pub fn iter_slices<'a, T: 'a + re_chunk::ChunkComponentSlicer>(
+    chunks: &'a std::borrow::Cow<'a, [Chunk]>,
+    timeline: Timeline,
+    component_name: ComponentName,
+) -> impl Iterator<Item = ((TimeInt, RowId), T::Item<'a>)> + 'a {
+    chunks.iter().flat_map(move |chunk| {
+        itertools::izip!(
+            chunk.iter_component_indices(&timeline, &component_name),
+            chunk.iter_slices::<T>(component_name)
+        )
+    })
+}