feat/shaper helper dedup

packages/glyph/rust/shaper/src/engine/cluster_state.rs

@@ -9,8 +9,9 @@ use crate::{FontGlyphExtents, FontMetrics, unicode::UnicodeAnalysis};
 use super::{
     EngineError, FrameFault,
     frame::{WRAP_CHARACTER, WRAP_NONE, WRAP_WORD},
-    identity_index::{IdentityIndex, IdentityIndexError},
+    identity_index::{IdentityIndex, identity_index_error},
     line_composition::Correction,
+    reserve_vec as reserve,
     run_local::{NumericBlockSpan, RunLocalArena},
     shaping_state::{ShapeArena, ShapingRun},
     style_state::{ResolvedStyle, StyleArena, StyleSegment},
@@ -1975,15 +1976,6 @@ fn is_hard_break(text: &[u16], start: u32) -> Result<bool, EngineError> {
     ))
 }
 
-fn reserve<T>(values: &mut Vec<T>, capacity: usize) -> Result<(), EngineError> {
-    if values.capacity() < capacity {
-        values
-            .try_reserve_exact(capacity.saturating_sub(values.len()))
-            .map_err(|_| EngineError::ResultTooLarge)?;
-    }
-    Ok(())
-}
-
 /// True exactly when the build scatter's destination equals every glyph's own
 /// index: the shaped runs tile the glyph array in array order and the source
 /// cluster ids never decrease across it, so per-cluster ordinals assign
@@ -2398,15 +2390,6 @@ fn glyph_slice<T>(values: &[T], range: core::ops::Range<usize>) -> Result<&[T],
     values.get(range).ok_or(EngineError::InvalidRequest)
 }
 
-fn identity_index_error(error: IdentityIndexError) -> EngineError {
-    match error {
-        IdentityIndexError::AllocationFailed | IdentityIndexError::ArithmeticOverflow => {
-            EngineError::ResultTooLarge
-        }
-        IdentityIndexError::DuplicateIdentity => EngineError::InvalidRequest,
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

packages/glyph/rust/shaper/src/engine/flow_composition.rs

@@ -921,7 +921,7 @@ impl FlowLayoutArena {
                 self.clear();
                 return Ok(false);
             }
-            let first_fragments = line_fragments(previous, line_index)?;
+            let first_fragments = previous.line_fragments(line_index)?;
             let Some(first_fragment) = first_fragments.first() else {
                 self.clear();
                 return Ok(false);
@@ -1281,7 +1281,8 @@ impl FlowLayoutArena {
             .iter()
             .rposition(|line| line.flow_thread_id == constraint.flow_thread_id);
         let cursor_start = if let Some(line_index) = previous_thread_line {
-            line_fragments(previous, line_index)?
+            previous
+                .line_fragments(line_index)?
                 .last()
                 .and_then(|fragment| usize::try_from(fragment.line.cluster_end).ok())
                 .ok_or(EngineError::InvalidRequest)?
@@ -2005,13 +2006,6 @@ fn shrink_for_flow_thread(
         .ok_or(EngineError::InvalidRequest)
 }
 
-fn line_fragments(
-    flow: &FlowLayoutArena,
-    line_index: usize,
-) -> Result<RopeRange<'_, FlowFragment>, EngineError> {
-    flow.line_fragments(line_index)
-}
-
 fn same_flow_line_records(
     left_line: FlowLine,
     left_fragments: &RopeRange<'_, FlowFragment>,

packages/glyph/rust/shaper/src/engine/identity_index.rs

@@ -2,13 +2,24 @@
 
 use alloc::vec::Vec;
 
+use super::EngineError;
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub(crate) enum IdentityIndexError {
     AllocationFailed,
     ArithmeticOverflow,
     DuplicateIdentity,
 }
 
+pub(super) fn identity_index_error(error: IdentityIndexError) -> EngineError {
+    match error {
+        IdentityIndexError::AllocationFailed | IdentityIndexError::ArithmeticOverflow => {
+            EngineError::ResultTooLarge
+        }
+        IdentityIndexError::DuplicateIdentity => EngineError::InvalidRequest,
+    }
+}
+
 #[derive(Default)]
 pub(crate) struct IdentityIndex {
     keys: Vec<u32>,

packages/glyph/rust/shaper/src/engine/mod.rs

@@ -3,6 +3,8 @@
 //! The public types in this module are available to native consumers. Wasm memory ownership and
 //! pointer validation stay in the target-gated transport module.
 
+use alloc::vec::Vec;
+
 mod cluster_state;
 #[cfg_attr(not(test), allow(dead_code))]
 mod flow_composition;
@@ -60,3 +62,12 @@ mod work_attribution;
 
 pub(crate) use positioning::SemanticGlyph;
 pub use state::{EngineError, FrameFault, TextEngine};
+
+fn reserve_vec<T>(values: &mut Vec<T>, capacity: usize) -> Result<(), EngineError> {
+    if values.capacity() < capacity {
+        values
+            .try_reserve_exact(capacity.saturating_sub(values.len()))
+            .map_err(|_| EngineError::ResultTooLarge)?;
+    }
+    Ok(())
+}

packages/glyph/rust/shaper/src/engine/positioning.rs

@@ -18,9 +18,10 @@ use super::{
     codec_gather::{LayoutGlyph, PAINT_LAYER_GLYPH},
     flow_composition::{FlowDropCap, FlowFragment, FlowLayoutArena, FlowLine},
     frame::{ALIGN_CENTER, ALIGN_END, ALIGN_JUSTIFY, ALIGN_START},
-    identity_index::{IdentityIndex, IdentityIndexError},
+    identity_index::{IdentityIndex, identity_index_error},
     line_composition::ComposedLine,
     placement_slot_arena::PlacementHandle,
+    reserve_vec as reserve,
     retained_rope::{RopeCursor, RopeCursorRange},
     run_local::{
         ClusterFinish, RunLocalArena, RunLocalBuildError, RunLocalGlyph, RunLocalGlyphInput,
@@ -4541,24 +4542,6 @@ fn nonnegative_f32(value: f64) -> Result<f32, EngineError> {
         .ok_or(EngineError::InvalidRequest)
 }
 
-fn identity_index_error(error: IdentityIndexError) -> EngineError {
-    match error {
-        IdentityIndexError::AllocationFailed | IdentityIndexError::ArithmeticOverflow => {
-            EngineError::ResultTooLarge
-        }
-        IdentityIndexError::DuplicateIdentity => EngineError::InvalidRequest,
-    }
-}
-
-fn reserve<T>(values: &mut Vec<T>, capacity: usize) -> Result<(), EngineError> {
-    if values.capacity() < capacity {
-        values
-            .try_reserve_exact(capacity.saturating_sub(values.len()))
-            .map_err(|_| EngineError::ResultTooLarge)?;
-    }
-    Ok(())
-}
-
 #[cfg(test)]
 mod tests {
     use super::super::{

packages/glyph/rust/shaper/src/engine/shaping_state.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 
 use super::{
-    EngineError,
+    EngineError, reserve_vec,
     style_state::{ResolvedStyle, StyleArena, StyleSegment},
 };
 
@@ -92,12 +92,7 @@ pub(crate) struct BoundaryShapeArena {
 
 impl ShapingRunArena {
     pub(crate) fn reserve(&mut self, capacity: usize) -> Result<(), EngineError> {
-        if self.runs.capacity() < capacity {
-            self.runs
-                .try_reserve_exact(capacity.saturating_sub(self.runs.len()))
-                .map_err(|_| EngineError::ResultTooLarge)?;
-        }
-        Ok(())
+        reserve_vec(&mut self.runs, capacity)
     }
 
     pub(crate) fn build(
@@ -580,15 +575,6 @@ impl BoundaryShapeArena {
     }
 }
 
-fn reserve_vec<T>(values: &mut Vec<T>, capacity: usize) -> Result<(), EngineError> {
-    if values.capacity() < capacity {
-        values
-            .try_reserve_exact(capacity.saturating_sub(values.len()))
-            .map_err(|_| EngineError::ResultTooLarge)?;
-    }
-    Ok(())
-}
-
 fn direction(style: ResolvedStyle, level: u8) -> u8 {
     if style.bidi_override {
         u8::from(style.direction == 2)