Layout readers don't need a mutable context

encodings/fastlanes/src/rle/array/mod.rs

@@ -229,6 +229,7 @@ mod tests {
     use vortex_array::validity::Validity;
     use vortex_buffer::Buffer;
     use vortex_buffer::ByteBufferMut;
+    use vortex_session::registry::ReadContext;
 
     use crate::RLEArray;
     use crate::test::SESSION;
@@ -458,7 +459,7 @@ mod tests {
             .decode(
                 &DType::Primitive(PType::U32, Nullability::NonNullable),
                 2048,
-                &ctx,
+                &ReadContext::new(ctx.to_ids()),
                 &SESSION,
             )
             .unwrap();
@@ -498,7 +499,12 @@ mod tests {
 
         let parts = ArrayParts::try_from(concat).unwrap();
         let decoded = parts
-            .decode(sliced.dtype(), sliced.len(), &ctx, &SESSION)
+            .decode(
+                sliced.dtype(),
+                sliced.len(),
+                &ReadContext::new(ctx.to_ids()),
+                &SESSION,
+            )
             .unwrap();
 
         let original_data = sliced.to_primitive();

encodings/pco/src/test.rs

@@ -27,6 +27,7 @@ use vortex_buffer::BufferMut;
 use vortex_error::VortexResult;
 use vortex_mask::Mask;
 use vortex_session::VortexSession;
+use vortex_session::registry::ReadContext;
 
 static SESSION: LazyLock<VortexSession> = LazyLock::new(|| {
     let session = VortexSession::empty().with::<ArraySession>();
@@ -166,7 +167,7 @@ fn test_serde() -> VortexResult<()> {
     let decoded = parts.decode(
         &DType::Primitive(PType::I32, Nullability::NonNullable),
         1_000_000,
-        &context,
+        &ReadContext::new(context.to_ids()),
         &SESSION,
     )?;
     let mut ctx = SESSION.create_execution_ctx();

vortex-array/public-api.lock

@@ -15982,7 +15982,7 @@ pub fn vortex_array::serde::ArrayParts::buffer_lengths(&self) -> alloc::vec::Vec
 
 pub fn vortex_array::serde::ArrayParts::child(&self, idx: usize) -> vortex_array::serde::ArrayParts
 
-pub fn vortex_array::serde::ArrayParts::decode(&self, dtype: &vortex_array::dtype::DType, len: usize, ctx: &vortex_array::ArrayContext, session: &vortex_session::VortexSession) -> vortex_error::VortexResult<vortex_array::ArrayRef>
+pub fn vortex_array::serde::ArrayParts::decode(&self, dtype: &vortex_array::dtype::DType, len: usize, ctx: &vortex_session::registry::ReadContext, session: &vortex_session::VortexSession) -> vortex_error::VortexResult<vortex_array::ArrayRef>
 
 pub fn vortex_array::serde::ArrayParts::encoding_id(&self) -> u16
 

vortex-array/src/arrays/decimal/vtable/mod.rs

@@ -239,6 +239,7 @@ impl DecimalVTable {
 mod tests {
     use vortex_buffer::ByteBufferMut;
     use vortex_buffer::buffer;
+    use vortex_session::registry::ReadContext;
 
     use crate::ArrayContext;
     use crate::IntoArray;
@@ -273,7 +274,9 @@ mod tests {
         let concat = concat.freeze();
 
         let parts = ArrayParts::try_from(concat).unwrap();
-        let decoded = parts.decode(&dtype, 5, &ctx, &LEGACY_SESSION).unwrap();
+        let decoded = parts
+            .decode(&dtype, 5, &ReadContext::new(ctx.to_ids()), &LEGACY_SESSION)
+            .unwrap();
         assert!(decoded.is::<DecimalVTable>());
     }
 }

vortex-array/src/arrays/masked/vtable/mod.rs

@@ -217,6 +217,7 @@ mod tests {
     use rstest::rstest;
     use vortex_buffer::ByteBufferMut;
     use vortex_error::VortexError;
+    use vortex_session::registry::ReadContext;
 
     use crate::ArrayContext;
     use crate::Canonical;
@@ -269,7 +270,14 @@ mod tests {
         let concat = concat.freeze();
 
         let parts = ArrayParts::try_from(concat).unwrap();
-        let decoded = parts.decode(&dtype, len, &ctx, &LEGACY_SESSION).unwrap();
+        let decoded = parts
+            .decode(
+                &dtype,
+                len,
+                &ReadContext::new(ctx.to_ids()),
+                &LEGACY_SESSION,
+            )
+            .unwrap();
 
         assert!(decoded.is::<MaskedVTable>());
         assert_eq!(

vortex-array/src/lib.rs

@@ -18,14 +18,15 @@ use std::sync::LazyLock;
 pub use array::*;
 pub use canonical::*;
 pub use columnar::*;
-pub use context::*;
 pub use executor::*;
 pub use hash::*;
 pub use mask_future::*;
 pub use metadata::*;
 use vortex_session::VortexSession;
+use vortex_session::registry::Context;
 
 use crate::session::ArraySession;
+use crate::vtable::DynVTable;
 
 pub mod accessor;
 #[doc(hidden)]
@@ -39,7 +40,6 @@ pub mod builtins;
 mod canonical;
 mod columnar;
 pub mod compute;
-mod context;
 pub mod display;
 pub mod dtype;
 mod executor;
@@ -80,3 +80,5 @@ pub mod flatbuffers {
 //  here...
 pub static LEGACY_SESSION: LazyLock<VortexSession> =
     LazyLock::new(|| VortexSession::empty().with::<ArraySession>());
+
+pub type ArrayContext = Context<&'static dyn DynVTable>;

vortex-array/src/serde.rs

@@ -24,6 +24,7 @@ use vortex_flatbuffers::WriteFlatBuffer;
 use vortex_flatbuffers::array as fba;
 use vortex_flatbuffers::array::Compression;
 use vortex_session::VortexSession;
+use vortex_session::registry::ReadContext;
 use vortex_utils::aliases::hash_map::HashMap;
 
 use crate::ArrayContext;
@@ -318,7 +319,7 @@ impl ArrayParts {
         &self,
         dtype: &DType,
         len: usize,
-        ctx: &ArrayContext,
+        ctx: &ReadContext,
         session: &VortexSession,
     ) -> VortexResult<ArrayRef> {
         let encoding_idx = self.flatbuffer().encoding();
@@ -623,7 +624,7 @@ impl ArrayParts {
 
 struct ArrayPartsChildren<'a> {
     parts: &'a ArrayParts,
-    ctx: &'a ArrayContext,
+    ctx: &'a ReadContext,
     session: &'a VortexSession,
 }
 

vortex-cuda/src/layout.rs

@@ -64,6 +64,7 @@ use vortex::scalar::ScalarTruncation;
 use vortex::scalar::lower_bound;
 use vortex::scalar::upper_bound;
 use vortex::session::VortexSession;
+use vortex::session::registry::ReadContext;
 use vortex::utils::aliases::hash_map::HashMap;
 
 /// A buffer inlined into layout metadata for host-side access.
@@ -94,7 +95,7 @@ pub struct CudaFlatLayout {
     row_count: u64,
     dtype: DType,
     segment_id: SegmentId,
-    ctx: ArrayContext,
+    ctx: ReadContext,
     array_tree: ByteBuffer,
     /// Small buffers kept on host, keyed by global buffer index.
     host_buffers: Arc<HashMap<u32, ByteBuffer>>,
@@ -107,7 +108,7 @@ impl CudaFlatLayout {
     }
 
     #[inline]
-    pub fn array_ctx(&self) -> &ArrayContext {
+    pub fn array_ctx(&self) -> &ReadContext {
         &self.ctx
     }
 
@@ -195,7 +196,7 @@ impl VTable for CudaFlatVTable {
         metadata: &<Self::Metadata as DeserializeMetadata>::Output,
         segment_ids: Vec<SegmentId>,
         _children: &dyn LayoutChildren,
-        ctx: &ArrayContext,
+        ctx: &ReadContext,
     ) -> VortexResult<Self::Layout> {
         if segment_ids.len() != 1 {
             vortex_bail!("CudaFlatLayout must have exactly one segment ID");
@@ -535,7 +536,7 @@ impl LayoutStrategy for CudaFlatLayoutStrategy {
             row_count,
             dtype: stream.dtype().clone(),
             segment_id,
-            ctx: ctx.clone(),
+            ctx: ReadContext::new(ctx.to_ids()),
             array_tree,
             host_buffers: Arc::new(host_buffer_map),
         }

vortex-file/src/footer/file_layout.rs

@@ -11,12 +11,11 @@ use std::sync::Arc;
 
 use flatbuffers::FlatBufferBuilder;
 use flatbuffers::WIPOffset;
-use vortex_array::ArrayContext;
 use vortex_error::VortexResult;
 use vortex_flatbuffers::FlatBufferRoot;
 use vortex_flatbuffers::WriteFlatBuffer;
 use vortex_flatbuffers::footer as fb;
-use vortex_layout::LayoutContext;
+use vortex_session::registry::ReadContext;
 
 use crate::footer::segment::SegmentSpec;
 
@@ -26,9 +25,9 @@ use crate::footer::segment::SegmentSpec;
 /// which describes the structure of the data in the file.
 pub(crate) struct FooterFlatBufferWriter {
     /// The array context containing encodings used in the file.
-    pub(crate) ctx: ArrayContext,
+    pub(crate) ctx: ReadContext,
     /// The layout context containing the layouts used in the file.
-    pub(crate) layout_ctx: LayoutContext,
+    pub(crate) layout_ctx: ReadContext,
     /// Specifications for all segments in the file.
     pub(crate) segment_specs: Arc<[SegmentSpec]>,
 }
@@ -47,7 +46,7 @@ impl WriteFlatBuffer for FooterFlatBufferWriter {
 
         let array_specs = self
             .ctx
-            .to_ids()
+            .ids()
             .iter()
             .map(|e| {
                 let id = fbb.create_string(e.as_ref());
@@ -58,7 +57,7 @@ impl WriteFlatBuffer for FooterFlatBufferWriter {
 
         let layout_specs = self
             .layout_ctx
-            .to_ids()
+            .ids()
             .iter()
             .map(|e| {
                 let id = fbb.create_string(e.as_ref());

vortex-file/src/footer/mod.rs

@@ -24,7 +24,6 @@ pub use file_statistics::FileStatistics;
 use flatbuffers::root;
 use itertools::Itertools;
 pub use segment::*;
-use vortex_array::ArrayContext;
 use vortex_array::dtype::DType;
 use vortex_array::vtable::ArrayId;
 use vortex_buffer::ByteBuffer;
@@ -33,12 +32,12 @@ use vortex_error::vortex_bail;
 use vortex_error::vortex_err;
 use vortex_flatbuffers::FlatBuffer;
 use vortex_flatbuffers::footer as fb;
-use vortex_layout::LayoutContext;
 use vortex_layout::LayoutEncodingId;
 use vortex_layout::LayoutRef;
 use vortex_layout::layout_from_flatbuffer;
 use vortex_layout::session::LayoutSessionExt;
 use vortex_session::VortexSession;
+use vortex_session::registry::ReadContext;
 
 /// Captures the layout information of a Vortex file.
 #[derive(Debug, Clone)]
@@ -47,7 +46,7 @@ pub struct Footer {
     segments: Arc<[SegmentSpec]>,
     statistics: Option<FileStatistics>,
     // The specific arrays used within the file, in the order they were registered.
-    array_ctx: ArrayContext,
+    array_read_ctx: ReadContext,
     // The approximate size of the footer in bytes, used for caching and memory management.
     approx_byte_size: Option<usize>,
 }
@@ -57,13 +56,13 @@ impl Footer {
         root_layout: LayoutRef,
         segments: Arc<[SegmentSpec]>,
         statistics: Option<FileStatistics>,
-        array_ctx: ArrayContext,
+        array_read_ctx: ReadContext,
     ) -> Self {
         Self {
             root_layout,
             segments,
             statistics,
-            array_ctx,
+            array_read_ctx,
             approx_byte_size: None,
         }
     }
@@ -86,27 +85,27 @@ impl Footer {
 
         // Create a LayoutContext from the registry.
         let layout_specs = fb_footer.layout_specs();
-        let layout_ids = layout_specs
+        let layout_ids: Arc<[_]> = layout_specs
             .iter()
             .flat_map(|e| e.iter())
             .map(|encoding| LayoutEncodingId::new_arc(Arc::from(encoding.id())))
             .collect();
-        let layout_ctx = LayoutContext::new(layout_ids);
+        let layout_read_ctx = ReadContext::new(layout_ids);
 
         // Create an ArrayContext from the registry.
         let array_specs = fb_footer.array_specs();
-        let array_ids = array_specs
+        let array_ids: Arc<[_]> = array_specs
             .iter()
             .flat_map(|e| e.iter())
             .map(|encoding| ArrayId::new_arc(Arc::from(encoding.id())))
             .collect();
-        let array_ctx = ArrayContext::new(array_ids);
+        let array_read_ctx = ReadContext::new(array_ids);
 
         let root_layout = layout_from_flatbuffer(
             layout_bytes,
             &dtype,
-            &layout_ctx,
-            &array_ctx,
+            &layout_read_ctx,
+            &array_read_ctx,
             session.layouts().registry(),
         )?;
 
@@ -126,7 +125,7 @@ impl Footer {
             root_layout,
             segments,
             statistics,
-            array_ctx,
+            array_read_ctx,
             approx_byte_size: Some(approx_byte_size),
         })
     }

vortex-file/src/footer/serializer.rs

@@ -10,6 +10,7 @@ use vortex_flatbuffers::FlatBufferRoot;
 use vortex_flatbuffers::WriteFlatBuffer;
 use vortex_flatbuffers::WriteFlatBufferExt;
 use vortex_layout::LayoutContext;
+use vortex_session::registry::ReadContext;
 
 use crate::EOF_SIZE;
 use crate::Footer;
@@ -94,8 +95,8 @@ impl FooterSerializer {
         let (buffer, footer_segment) = write_flatbuffer(
             &mut self.offset,
             &FooterFlatBufferWriter {
-                ctx: self.footer.array_ctx.clone(),
-                layout_ctx,
+                ctx: self.footer.array_read_ctx.clone(),
+                layout_ctx: ReadContext::new(layout_ctx.to_ids()),
                 segment_specs: self.footer.segments.clone(),
             },
         )?;

vortex-file/src/writer.rs

@@ -45,6 +45,7 @@ use vortex_layout::sequence::SequentialStreamAdapter;
 use vortex_layout::sequence::SequentialStreamExt;
 use vortex_session::SessionExt;
 use vortex_session::VortexSession;
+use vortex_session::registry::ReadContext;
 
 use crate::Footer;
 use crate::MAGIC_BYTES;
@@ -211,7 +212,7 @@ impl VortexWriteOptions {
                     &dtype,
                 ))
             },
-            ctx,
+            ReadContext::new(ctx.to_ids()),
         );
 
         // Emit the footer buffers and EOF.

vortex-ipc/public-api.lock

@@ -46,7 +46,7 @@ pub mod vortex_ipc::messages
 
 pub enum vortex_ipc::messages::DecoderMessage
 
-pub vortex_ipc::messages::DecoderMessage::Array((vortex_array::serde::ArrayParts, vortex_array::context::ArrayContext, usize))
+pub vortex_ipc::messages::DecoderMessage::Array((vortex_array::serde::ArrayParts, vortex_session::registry::ReadContext, usize))
 
 pub vortex_ipc::messages::DecoderMessage::Buffer(vortex_buffer::ByteBuffer)