[stdlib] Implement native grapheme breaking for String (swiftlang#37864)

* Implement GraphemeWalker that does native grapheme breaking

* Bridged strings use native grapheme breaking for forward strides

* Implement bidirectional native grapheme breaking for native and foreign strings

* Remove ICU's grapheme breaking support

* Use UnicodeScalarView to implement GraphemeWalker

use an Iterator approach

remove Iterator conformance

* Incorporate Michael's feedback

more comments addressed

fix crlf bug

* Try bringing back some old fast paths

* Parameterize nextBoundary and previousBoundary

Parameterize nextBoundary and previousBoundary

* Implement Michael's suggestions

Author: Azoy

stdlib/public/SwiftShims/UnicodeData.h

@@ -40,6 +40,9 @@ __swift_intptr_t _swift_stdlib_getMphIdx(__swift_uint32_t scalar,
                                          const __swift_uint16_t * const *ranks,
                                          const __swift_uint16_t * const sizes);
 
+SWIFT_RUNTIME_STDLIB_INTERNAL
+__swift_uint8_t _swift_stdlib_getGraphemeBreakProperty(__swift_uint32_t scalar);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

stdlib/public/SwiftShims/UnicodeShims.h

@@ -29,39 +29,6 @@
 extern "C" {
 #endif
 
-SWIFT_RUNTIME_STDLIB_API
-const __swift_uint8_t *_swift_stdlib_GraphemeClusterBreakPropertyTrie;
-
-struct _swift_stdlib_GraphemeClusterBreakPropertyTrieMetadataTy {
-  unsigned BMPFirstLevelIndexBits;
-  unsigned BMPDataOffsetBits;
-  unsigned SuppFirstLevelIndexBits;
-  unsigned SuppSecondLevelIndexBits;
-  unsigned SuppDataOffsetBits;
-
-  unsigned BMPLookupBytesPerEntry;
-  unsigned BMPDataBytesPerEntry;
-  unsigned SuppLookup1BytesPerEntry;
-  unsigned SuppLookup2BytesPerEntry;
-  unsigned SuppDataBytesPerEntry;
-
-  unsigned TrieSize;
-
-  unsigned BMPLookupBytesOffset;
-  unsigned BMPDataBytesOffset;
-  unsigned SuppLookup1BytesOffset;
-  unsigned SuppLookup2BytesOffset;
-  unsigned SuppDataBytesOffset;
-};
-
-SWIFT_RUNTIME_STDLIB_API
-const struct _swift_stdlib_GraphemeClusterBreakPropertyTrieMetadataTy
-_swift_stdlib_GraphemeClusterBreakPropertyTrieMetadata;
-
-SWIFT_RUNTIME_STDLIB_API
-const __swift_uint16_t *
-_swift_stdlib_ExtendedGraphemeClusterNoBoundaryRulesMatrix;
-
 SWIFT_RUNTIME_STDLIB_API
 __swift_int32_t _swift_stdlib_unicode_strToUpper(
   __swift_uint16_t *Destination, __swift_int32_t DestinationCapacity,
@@ -362,17 +329,6 @@ typedef enum __swift_stdlib_UErrorCode {
   __swift_stdlib_U_ERROR_LIMIT = __swift_stdlib_U_PLUGIN_ERROR_LIMIT
 } __swift_stdlib_UErrorCode;
 
-typedef enum __swift_stdlib_UBreakIteratorType {
-  __swift_stdlib_UBRK_CHARACTER = 0,
-  __swift_stdlib_UBRK_WORD = 1,
-  __swift_stdlib_UBRK_LINE = 2,
-  __swift_stdlib_UBRK_SENTENCE = 3,
-#ifndef U_HIDE_DEPRECATED_API
-  __swift_stdlib_UBRK_TITLE = 4,
-#endif
-  __swift_stdlib_UBRK_COUNT = 5
-} __swift_stdlib_UBreakIteratorType;
-
 typedef enum __swift_stdlib_UCharCategory {
   __swift_stdlib_U_UNASSIGNED              = 0,
   __swift_stdlib_U_GENERAL_OTHER_TYPES     = 0,
@@ -447,47 +403,6 @@ typedef __swift_uint16_t __swift_stdlib_UChar;
 typedef __swift_uint8_t
     __swift_stdlib_UVersionInfo[__SWIFT_STDLIB_U_MAX_VERSION_LENGTH];
 
-SWIFT_RUNTIME_STDLIB_API
-void __swift_stdlib_ubrk_close(__swift_stdlib_UBreakIterator *bi);
-
-SWIFT_RUNTIME_STDLIB_API
-__swift_stdlib_UBreakIterator *
-__swift_stdlib_ubrk_open(__swift_stdlib_UBreakIteratorType type,
-                         const char *_Nullable locale,
-                         const __swift_stdlib_UChar *_Null_unspecified text,
-                         __swift_int32_t textLength,
-                         __swift_stdlib_UErrorCode *status);
-
-SWIFT_RUNTIME_STDLIB_API
-void __swift_stdlib_ubrk_setUText(__swift_stdlib_UBreakIterator *bi,
-                                  __swift_stdlib_UText *text,
-                                  __swift_stdlib_UErrorCode *status);
-
-SWIFT_RUNTIME_STDLIB_API
-void __swift_stdlib_ubrk_setText(__swift_stdlib_UBreakIterator *bi,
-                                 const __swift_stdlib_UChar *text,
-                                 __swift_int32_t textLength,
-                                 __swift_stdlib_UErrorCode *status);
-
-SWIFT_RUNTIME_STDLIB_API
-__swift_stdlib_UText *
-__swift_stdlib_utext_openUTF8(__swift_stdlib_UText *_Nullable, const char *,
-                              __swift_int64_t, __swift_stdlib_UErrorCode *);
-
-SWIFT_RUNTIME_STDLIB_API
-__swift_stdlib_UText *
-__swift_stdlib_utext_openUChars(__swift_stdlib_UText *_Nullable,
-                                const __swift_stdlib_UChar *, __swift_int64_t,
-                                __swift_stdlib_UErrorCode *);
-
-SWIFT_RUNTIME_STDLIB_API
-__swift_int32_t __swift_stdlib_ubrk_preceding(__swift_stdlib_UBreakIterator *bi,
-                                              __swift_int32_t offset);
-
-SWIFT_RUNTIME_STDLIB_API
-__swift_int32_t __swift_stdlib_ubrk_following(__swift_stdlib_UBreakIterator *bi,
-                                              __swift_int32_t offset);
-
 SWIFT_RUNTIME_STDLIB_API
 __swift_stdlib_UBool
     __swift_stdlib_u_hasBinaryProperty(__swift_stdlib_UChar32,

stdlib/public/core/CMakeLists.txt

@@ -177,6 +177,7 @@ set(SWIFTLIB_ESSENTIAL
   UnavailableStringAPIs.swift
   UnicodeData.swift
   UnicodeEncoding.swift
+  UnicodeGraphemeBreakProperty.swift
   UnicodeHelpers.swift
   UnicodeParser.swift
   UnicodeScalarProperties.swift

stdlib/public/core/GroupInfo.json

@@ -45,6 +45,7 @@
     "Unicode.swift",
     "UnicodeData.swift",
     "UnicodeEncoding.swift",
+    "UnicodeGraphemeBreakProperty.swift",
     "UnicodeHelpers.swift",
     "UnicodeParser.swift",
     "UnicodeScalar.swift",