From 635e8e8e5ce907597515f0729d1a860d78a22750 Mon Sep 17 00:00:00 2001
From: snktd <90648681+snktd@users.noreply.github.com>
Date: Tue, 7 Jun 2022 18:05:50 -0500
Subject: [PATCH] Create wrapper object for ScriptExtensions array return value
  #1536 (#1990)

* Create wrapper object for ScriptExtensions array return value #1536

* #1536 Create wrapper object for ScriptExtensions array return value

* Resolving a minor issue with code comments.

* Update components/properties/src/script.rs

Co-authored-by: Shane F. Carr <shane@unicode.org>

* Addressing review comments.

* Making ScriptExtensionsSet.values private

* Addressing a minor review comment.

Co-authored-by: Shane F. Carr <shane@unicode.org>
---
 components/properties/src/script.rs           | 66 ++++++++++++++++---
 .../datagen/src/transform/uprops/script.rs    | 61 ++++++++++++-----
 2 files changed, 102 insertions(+), 25 deletions(-)

diff --git a/components/properties/src/script.rs b/components/properties/src/script.rs
index eeaec44b648..a20f2af1314 100644
--- a/components/properties/src/script.rs
+++ b/components/properties/src/script.rs
@@ -174,6 +174,55 @@ impl From<ScriptWithExt> for Script {
     }
 }
 
+/// A data structure that wraps ScriptExtensions array return value.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub struct ScriptExtensionsSet<'a> {
+    values: &'a ZeroSlice<Script>,
+}
+
+impl ScriptExtensionsSet<'_> {
+    /// Returns whether this set contains the given script.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use icu::properties::{script, Script};
+    /// let provider = icu_testdata::get_provider();
+    /// let payload = script::get_script_with_extensions(&provider).expect("The data should be valid");
+    /// let data_struct = payload.get();
+    /// let swe = &data_struct.data;
+    ///
+    /// assert!(swe
+    ///    .get_script_extensions_val(0x11303) // GRANTHA SIGN VISARGA
+    ///    .contains(&Script::Grantha));
+    /// ```
+    pub fn contains(&self, x: &Script) -> bool {
+        ZeroSlice::binary_search(&*self.values, x).is_ok()
+    }
+
+    /// Gets an iterator over the elements.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use icu::properties::{script, Script};
+    /// let provider = icu_testdata::get_provider();
+    /// let payload = script::get_script_with_extensions(&provider).expect("The data should be valid");
+    /// let data_struct = payload.get();
+    /// let swe = &data_struct.data;
+    ///
+    /// assert_eq!(
+    ///     swe.get_script_extensions_val('௫' as u32) // U+0BEB TAMIL DIGIT FIVE
+    ///         .iter()
+    ///         .collect::<Vec<Script>>(),
+    ///     vec![Script::Tamil, Script::Grantha]
+    /// );
+    /// ```
+    pub fn iter(&self) -> impl DoubleEndedIterator<Item = Script> + '_ {
+        ZeroSlice::iter(&*self.values)
+    }
+}
+
 /// A data structure that represents the data for both Script and
 /// Script_Extensions properties in an efficient way. This structure matches
 /// the data and data structures that are stored in the corresponding ICU data
@@ -317,12 +366,12 @@ impl<'data> ScriptWithExtensions<'data> {
     ///
     /// If `code_point` has Script_Extensions, then return the Script codes in
     /// the Script_Extensions. In this case, the Script property value
-    /// (normally Common or Inherited) is not included in the [`ZeroSlice`].
+    /// (normally Common or Inherited) is not included in the [`ScriptExtensionsSet`].
     ///
     /// If c does not have Script_Extensions, then the one Script code is put
-    /// into the [`ZeroSlice`] and also returned.
+    /// into the [`ScriptExtensionsSet`] and also returned.
     ///
-    /// If c is not a valid code point, then return an empty [`ZeroSlice`].
+    /// If c is not a valid code point, then return an empty [`ScriptExtensionsSet`].
     ///
     /// # Examples
     ///
@@ -360,15 +409,16 @@ impl<'data> ScriptWithExtensions<'data> {
     ///     vec![Script::Tamil, Script::Grantha]
     /// );
     /// ```
-    pub fn get_script_extensions_val(&self, code_point: u32) -> &ZeroSlice<Script> {
+    pub fn get_script_extensions_val(&self, code_point: u32) -> ScriptExtensionsSet {
         let sc_with_ext_ule = self.trie.get_ule(code_point);
 
-        match sc_with_ext_ule {
-            Some(ule_ref) => self.get_scx_val_using_trie_val(ule_ref),
-            None => ZeroSlice::from_ule_slice(&[]),
+        ScriptExtensionsSet {
+            values: match sc_with_ext_ule {
+                Some(ule_ref) => self.get_scx_val_using_trie_val(ule_ref),
+                None => ZeroSlice::from_ule_slice(&[]),
+            },
         }
     }
-
     /// Returns whether `script` is contained in the Script_Extensions
     /// property value if the code_point has Script_Extensions, otherwise
     /// if the code point does not have Script_Extensions then returns
diff --git a/provider/datagen/src/transform/uprops/script.rs b/provider/datagen/src/transform/uprops/script.rs
index a0ffff79b05..c0cf484295e 100644
--- a/provider/datagen/src/transform/uprops/script.rs
+++ b/provider/datagen/src/transform/uprops/script.rs
@@ -115,8 +115,6 @@ mod tests {
 
     #[test]
     fn test_scx_array_from_script_extensions() {
-        use zerovec::ZeroVec;
-
         let provider = ScriptWithExtensionsPropertyProvider::from(&SourceData::for_test());
 
         let payload: DataPayload<ScriptWithExtensionsPropertyV1Marker> = provider
@@ -131,34 +129,63 @@ mod tests {
         let swe: &ScriptWithExtensions = &payload.get().data;
 
         assert_eq!(
-            swe.get_script_extensions_val('𐓐' as u32).as_zerovec(), /* U+104D0 OSAGE CAPITAL LETTER KHA */
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Osage])
+            swe.get_script_extensions_val('𐓐' as u32) /* U+104D0 OSAGE CAPITAL LETTER KHA */
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Osage]
+        );
+        assert_eq!(
+            swe.get_script_extensions_val('🥳' as u32) /* U+1F973 FACE WITH PARTY HORN AND PARTY HAT */
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Common]
         );
         assert_eq!(
-            swe.get_script_extensions_val('🥳' as u32).as_zerovec(), /* U+1F973 FACE WITH PARTY HORN AND PARTY HAT */
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Common])
+            swe.get_script_extensions_val(0x200D) // ZERO WIDTH JOINER
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Inherited]
         );
         assert_eq!(
-            swe.get_script_extensions_val(0x200D).as_zerovec(), // ZERO WIDTH JOINER
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Inherited])
+            swe.get_script_extensions_val('௫' as u32) // U+0BEB TAMIL DIGIT FIVE
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Tamil, Script::Grantha]
         );
         assert_eq!(
-            swe.get_script_extensions_val('௫' as u32).as_zerovec(), // U+0BEB TAMIL DIGIT FIVE
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Tamil, Script::Grantha])
+            swe.get_script_extensions_val(0x11303) // GRANTHA SIGN VISARGA
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Tamil, Script::Grantha]
         );
         assert_eq!(
-            swe.get_script_extensions_val(0x11303).as_zerovec(), // GRANTHA SIGN VISARGA
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Tamil, Script::Grantha])
+            swe.get_script_extensions_val(0x30A0) // KATAKANA-HIRAGANA DOUBLE HYPHEN
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Hiragana, Script::Katakana]
         );
+
         assert_eq!(
-            swe.get_script_extensions_val(0x30A0).as_zerovec(), // KATAKANA-HIRAGANA DOUBLE HYPHEN
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Hiragana, Script::Katakana])
+            swe.get_script_extensions_val(0x200D) // ZERO WIDTH JOINER
+                .iter()
+                .next(),
+            Some(Script::Inherited)
         );
 
-        // Invalid code point
+        assert!(swe
+            .get_script_extensions_val(0x11303) // GRANTHA SIGN VISARGA
+            .contains(&Script::Grantha));
+
+        assert!(!swe
+            .get_script_extensions_val(0x11303) // GRANTHA SIGN VISARGA
+            .contains(&Script::Common));
+
+        // // Invalid code point
         assert_eq!(
-            swe.get_script_extensions_val(0x11_0000).as_zerovec(), // CODE_POINT_MAX + 1 is invalid
-            ZeroVec::<Script>::alloc_from_slice(&[Script::Unknown])
+            swe.get_script_extensions_val(0x11_0000) // CODE_POINT_MAX + 1 is invalid
+                .iter()
+                .collect::<Vec<Script>>(),
+            vec![Script::Unknown]
         );
     }