Make UTS 46 normalization non-experimental

components/normalizer/src/lib.rs

@@ -70,6 +70,7 @@ extern crate alloc;
 mod error;
 pub mod properties;
 pub mod provider;
+pub mod uts46;
 
 pub use crate::error::NormalizerError;
 
@@ -79,7 +80,6 @@ pub use NormalizerError as Error;
 use crate::provider::CanonicalDecompositionDataV1Marker;
 use crate::provider::CompatibilityDecompositionSupplementV1Marker;
 use crate::provider::DecompositionDataV1;
-#[cfg(feature = "experimental")]
 use crate::provider::Uts46DecompositionSupplementV1Marker;
 use alloc::string::String;
 use alloc::vec::Vec;
@@ -106,20 +106,30 @@ use zerovec::{zeroslice, ZeroSlice};
 #[derive(Debug)]
 enum SupplementPayloadHolder {
  Compatibility(DataPayload<CompatibilityDecompositionSupplementV1Marker>),
- #[cfg(feature = "experimental")]
  Uts46(DataPayload<Uts46DecompositionSupplementV1Marker>),
 }
 
 impl SupplementPayloadHolder {
  fn get(&self) -> &DecompositionSupplementV1 {
  match self {
  SupplementPayloadHolder::Compatibility(d) => d.get(),
- #[cfg(feature = "experimental")]
  SupplementPayloadHolder::Uts46(d) => d.get(),
  }
  }
 }
 
+/// Treatment of the ignorable marker (0xFFFFFFFF) in data.
+#[derive(Debug, PartialEq, Eq)]
+enum IgnorableBehavior {
+ /// 0xFFFFFFFF in data is not supported.
+ Unsupported,
+ /// Ignorables are ignored.
+ Ignored,
+ /// Ignorables are treated as singleton decompositions
+ /// to the REPLACEMENT CHARACTER.
+ ReplacementCharacter,
+}
+
 /// Number of iterations allowed on the fast path before flushing.
 /// Since a typical UTF-16 iteration advances over a 2-byte BMP
 /// character, this means two memory pages.
@@ -132,6 +142,9 @@ impl SupplementPayloadHolder {
 /// passes an error through from `Write`.
 const UTF16_FAST_PATH_FLUSH_THRESHOLD: usize = 4096;
 
+/// Marker for UTS 46 ignorables.
+const IGNORABLE_MARKER: u32 = 0xFFFFFFFF;
+
 /// Marker for starters that decompose to themselves but may
 /// combine backwards under canonical composition.
 /// (Main trie only; not used in the supplementary trie.)
@@ -528,6 +541,7 @@ where
  /// 1. Decomposes to self.
  /// 2. Decomposition starts with a non-starter
  decomposition_passthrough_bound: u32, // never above 0xC0
+ ignorable_behavior: IgnorableBehavior, // Arguably should be a type parameter
 }
 
 impl<'data, I> Decomposition<'data, I>
@@ -549,7 +563,15 @@ where
  decompositions: &'data DecompositionDataV1,
  tables: &'data DecompositionTablesV1,
  ) -> Self {
- Self::new_with_supplements(delegate, decompositions, None, tables, None, 0xC0)
+ Self::new_with_supplements(
+ delegate,
+ decompositions,
+ None,
+ tables,
+ None,
+ 0xC0,
+ IgnorableBehavior::Unsupported,
+ )
  }
 
  /// Constructs a decomposing iterator adapter from a delegate
@@ -565,6 +587,7 @@ where
  tables: &'data DecompositionTablesV1,
  supplementary_tables: Option<&'data DecompositionTablesV1>,
  decomposition_passthrough_bound: u8,
+ ignorable_behavior: IgnorableBehavior,
  ) -> Self {
  let half_width_voicing_marks_become_non_starters =
  if let Some(supplementary) = supplementary_decompositions {
@@ -595,6 +618,7 @@ where
  },
  half_width_voicing_marks_become_non_starters,
  decomposition_passthrough_bound: u32::from(decomposition_passthrough_bound),
+ ignorable_behavior,
  };
  let _ = ret.next(); // Remove the U+FFFF placeholder
  ret
@@ -721,16 +745,42 @@ where
 
  fn delegate_next_no_pending(&mut self) -> Option<CharacterAndTrieValue> {
  debug_assert!(self.pending.is_none());
- let c = self.delegate.next()?;
+ loop {
+ let c = self.delegate.next()?;
 
- // TODO(#2384): Measure if this check is actually an optimization even in the
- // non-supplementary case of if this should go inside the supplementary
- // `if` below.
- if u32::from(c) < self.decomposition_passthrough_bound {
- return Some(CharacterAndTrieValue::new(c, 0));
- }
+  // TODO(#2384): Measure if this check is actually an optimization even in the
+  // non-supplementary case of if this should go inside the supplementary
+  // `if` below.
+  if u32::from(c) < self.decomposition_passthrough_bound {
+  return Some(CharacterAndTrieValue::new(c, 0));
+  }
 
- Some(self.attach_trie_value(c))
+ if let Some(supplementary) = self.supplementary_trie {
+ if let Some(value) = self.attach_supplementary_trie_value(c, supplementary) {
+ if value.trie_val == IGNORABLE_MARKER {
+ match self.ignorable_behavior {
+ IgnorableBehavior::Unsupported => {
+ debug_assert!(false);
+ }
+ IgnorableBehavior::ReplacementCharacter => {
+ return Some(CharacterAndTrieValue::new(
+ c,
+ u32::from(REPLACEMENT_CHARACTER),
+ ));
+ }
+ IgnorableBehavior::Ignored => {
+ // Else ignore this character by reading the next one from the delegate.
+ continue;
+ }
+ }
+ }
+ return Some(value);
+ }
+ }
+ let trie_val = self.trie.get(c);
+ debug_assert_ne!(trie_val, IGNORABLE_MARKER);
+ return Some(CharacterAndTrieValue::new(c, trie_val));
+ }
  }
 
  fn delegate_next(&mut self) -> Option<CharacterAndTrieValue> {
@@ -1229,6 +1279,7 @@ macro_rules! composing_normalize_to {
  ) -> core::fmt::Result {
  $prolog
  let mut $composition = self.normalize_iter($text.chars());
+ debug_assert_eq!($composition.decomposition.ignorable_behavior, IgnorableBehavior::Unsupported);
  for cc in $composition.decomposition.buffer.drain(..) {
  $sink.write_char(cc.character())?;
  }
@@ -1416,6 +1467,7 @@ macro_rules! decomposing_normalize_to {
  $prolog
 
  let mut $decomposition = self.normalize_iter($text.chars());
+ debug_assert_eq!($decomposition.ignorable_behavior, IgnorableBehavior::Unsupported);
 
  // Try to get the compiler to hoist the bound to a register.
  let $decomposition_passthrough_bound = $decomposition.decomposition_passthrough_bound;
@@ -1730,8 +1782,8 @@ impl DecomposingNormalizer {
  }
 
  #[doc(hidden)]
- #[cfg(all(feature = "experimental", feature = "compiled_data"))]
- pub const fn new_uts46_decomposed_without_ignored_and_disallowed() -> Self {
+ #[cfg(feature = "compiled_data")]
+ pub(crate) const fn new_uts46_decomposed() -> Self {
  const _: () = assert!(
  crate::provider::Baked::SINGLETON_NORMALIZER_NFDEX_V1
  .scalars16
@@ -1807,8 +1859,7 @@ impl DecomposingNormalizer {
  ///
  /// Public for testing only.
  #[doc(hidden)]
- #[cfg(feature = "experimental")]
- pub fn try_new_uts46_decomposed_without_ignored_and_disallowed_unstable<D>(
+ pub(crate) fn try_new_uts46_decomposed_unstable<D>(
  provider: &D,
  ) -> Result<Self, NormalizerError>
  where
@@ -1872,6 +1923,7 @@ impl DecomposingNormalizer {
  self.tables.get(),
  self.supplementary_tables.as_ref().map(|s| s.get()),
  self.decomposition_passthrough_bound,
+ IgnorableBehavior::Unsupported,
  )
  }
 
@@ -2241,52 +2293,27 @@ impl ComposingNormalizer {
  })
  }
 
- /// See [`Self::try_new_uts46_without_ignored_and_disallowed_unstable`].
- #[cfg(all(feature = "experimental", feature = "compiled_data"))]
- pub const fn new_uts46_without_ignored_and_disallowed() -> Self {
- ComposingNormalizer {
- decomposing_normalizer:
- DecomposingNormalizer::new_uts46_decomposed_without_ignored_and_disallowed(),
- canonical_compositions: DataPayload::from_static_ref(
- crate::provider::Baked::SINGLETON_NORMALIZER_COMP_V1,
- ),
- }
- }
-
- /// 🚧 \[Experimental\] UTS 46 constructor
- ///
  /// This is a special building block normalization for IDNA that implements parts of the Map
- /// step and the following Normalize step. The caller is responsible for performing the
- /// "disallowed", "ignored", and "deviation" parts of the Map step before passing data to
- /// this normalizer such that disallowed and ignored characters aren't passed to this
- /// normalizer.
- ///
- /// This is ICU4C's UTS 46 normalization with two exceptions: characters that UTS 46 disallows
- /// and ICU4C maps to U+FFFD and characters that UTS 46 maps to the empty string normalize as
- /// in NFC in this normalization. Making the disallowed characters behave like this is beneficial
- /// to data size, and this normalizer implementation cannot deal with a character normalizing
- /// to the empty string, which doesn't happen in NFC or NFKC as of Unicode 14.
+ /// step and the following Normalize step.
  ///
  /// Warning: In this normalization, U+0345 COMBINING GREEK YPOGEGRAMMENI exhibits a behavior
  /// that no character in Unicode exhibits in NFD, NFKD, NFC, or NFKC: Case folding turns
  /// U+0345 from a reordered character into a non-reordered character before reordering happens.
  /// Therefore, the output of this normalization may differ for different inputs that are
  /// canonically equivalents with each other if they differ by how U+0345 is ordered relative
  /// to other reorderable characters.
- ///
- /// NOTE: This method remains experimental until suitability of this feature as part of
- /// IDNA processing has been demonstrated.
- ///
- /// <div class="stab unstable">
- /// 🚧 This code is experimental; it may change at any time, in breaking or non-breaking ways,
- /// including in SemVer minor releases. It can be enabled with the "experimental" Cargo feature
- /// of the icu meta-crate. Use with caution.
- /// <a href="https://github.com/unicode-org/icu4x/issues/2614">#2614</a>
- /// </div>
- #[cfg(feature = "experimental")]
- pub fn try_new_uts46_without_ignored_and_disallowed_unstable<D>(
- provider: &D,
- ) -> Result<Self, NormalizerError>
+ #[cfg(feature = "compiled_data")]
+ pub(crate) const fn new_uts46() -> Self {
+ ComposingNormalizer {
+ decomposing_normalizer: DecomposingNormalizer::new_uts46_decomposed(),
+ canonical_compositions: DataPayload::from_static_ref(
+ crate::provider::Baked::SINGLETON_NORMALIZER_COMP_V1,
+ ),
+ }
+ }
+
+ #[doc = icu_provider::gen_any_buffer_unstable_docs!(UNSTABLE, Self::new_uts46)]
+ pub(crate) fn try_new_uts46_unstable<D>(provider: &D) -> Result<Self, NormalizerError>
  where
  D: DataProvider<CanonicalDecompositionDataV1Marker>
  + DataProvider<Uts46DecompositionSupplementV1Marker>
@@ -2297,9 +2324,7 @@ impl ComposingNormalizer {
  + ?Sized,
  {
  let decomposing_normalizer =
- DecomposingNormalizer::try_new_uts46_decomposed_without_ignored_and_disallowed_unstable(
- provider,
- )?;
+ DecomposingNormalizer::try_new_uts46_decomposed_unstable(provider)?;
 
  let canonical_compositions: DataPayload<CanonicalCompositionsV1Marker> =
  provider.load(Default::default())?.take_payload()?;
@@ -2313,6 +2338,14 @@ impl ComposingNormalizer {
  /// Wraps a delegate iterator into a composing iterator
  /// adapter by using the data already held by this normalizer.
  pub fn normalize_iter<I: Iterator<Item = char>>(&self, iter: I) -> Composition<I> {
+ self.normalize_iter_private(iter, IgnorableBehavior::Unsupported)
+ }
+
+ fn normalize_iter_private<I: Iterator<Item = char>>(
+ &self,
+ iter: I,
+ ignorable_behavior: IgnorableBehavior,
+ ) -> Composition<I> {
  Composition::new(
  Decomposition::new_with_supplements(
  iter,
@@ -2327,6 +2360,7 @@ impl ComposingNormalizer {
  .as_ref()
  .map(|s| s.get()),
  self.decomposing_normalizer.decomposition_passthrough_bound,
+ ignorable_behavior,
  ),
  ZeroFrom::zero_from(&self.canonical_compositions.get().canonical_compositions),
  self.decomposing_normalizer.composition_passthrough_bound,