Move bidi methods to BidiUtil.

core-util/src/main/java/org/signal/core/util/StringUtil.kt

@@ -4,7 +4,6 @@ import android.text.SpannableStringBuilder
 import java.io.ByteArrayOutputStream
 import java.io.IOException
 import java.nio.charset.StandardCharsets
-import java.util.regex.Pattern
 
 object StringUtil {
   private val WHITESPACE: Set<Char> = setOf(
@@ -15,34 +14,6 @@ object StringUtil {
     '\u2800' // braille blank
   )
 
-  private val ALL_ASCII_PATTERN: Pattern = Pattern.compile("^[\\x00-\\x7F]*$")
-
-  private object Bidi {
-    /** Override text direction   */
-    val OVERRIDES: Set<Int> = SetUtil.newHashSet(
-      "\u202a".codePointAt(0), /* LRE */
-      "\u202b".codePointAt(0), /* RLE */
-      "\u202d".codePointAt(0), /* LRO */
-      "\u202e".codePointAt(0) /* RLO */
-    )
-
-    /** Set direction and isolate surrounding text  */
-    val ISOLATES: Set<Int> = SetUtil.newHashSet(
-      "\u2066".codePointAt(0), /* LRI */
-      "\u2067".codePointAt(0), /* RLI */
-      "\u2068".codePointAt(0) /* FSI */
-    )
-
-    /** Closes things in [.OVERRIDES]  */
-    val PDF: Int = "\u202c".codePointAt(0)
-
-    /** Closes things in [.ISOLATES]  */
-    val PDI: Int = "\u2069".codePointAt(0)
-
-    /** Auto-detecting isolate  */
-    val FSI: Int = "\u2068".codePointAt(0)
-  }
-
   /**
    * Trims a name string to fit into the byte length requirement.
    *
@@ -172,37 +143,6 @@ object StringUtil {
     return String(Character.toChars(codePoint))
   }
 
-  /**
-   * @return True if the provided text contains a mix of LTR and RTL characters, otherwise false.
-   */
-  @JvmStatic
-  fun hasMixedTextDirection(text: CharSequence?): Boolean {
-    if (text == null) {
-      return false
-    }
-
-    var isLtr: Boolean? = null
-
-    var i = 0
-    val len = Character.codePointCount(text, 0, text.length)
-    while (i < len) {
-      val codePoint = Character.codePointAt(text, i)
-      val direction = Character.getDirectionality(codePoint)
-      val isLetter = Character.isLetter(codePoint)
-
-      if (isLtr != null && isLtr && direction != Character.DIRECTIONALITY_LEFT_TO_RIGHT && isLetter) {
-        return true
-      } else if (isLtr != null && !isLtr && direction != Character.DIRECTIONALITY_RIGHT_TO_LEFT && isLetter) {
-        return true
-      } else if (isLetter) {
-        isLtr = direction == Character.DIRECTIONALITY_LEFT_TO_RIGHT
-      }
-      i++
-    }
-
-    return false
-  }
-
   /**
    * @return True if the text is null or has a length of 0, otherwise false.
    */
@@ -211,87 +151,6 @@ object StringUtil {
     return text.isNullOrEmpty()
   }
 
-  /**
-   * Isolates bi-directional text from influencing surrounding text. You should use this whenever
-   * you're injecting user-generated text into a larger string.
-   *
-   * You'd think we'd be able to trust BidiFormatter, but unfortunately it just misses some
-   * corner cases, so here we are.
-   *
-   * The general idea is just to balance out the opening and closing codepoints, and then wrap the
-   * whole thing in FSI/PDI to isolate it.
-   *
-   * For more details, see:
-   * https://www.w3.org/International/questions/qa-bidi-unicode-controls
-   */
-  @JvmStatic
-  fun isolateBidi(text: String?): String {
-    if (text == null) {
-      return ""
-    }
-
-    if (isEmpty(text)) {
-      return text
-    }
-
-    if (ALL_ASCII_PATTERN.matcher(text).matches()) {
-      return text
-    }
-
-    var overrideCount = 0
-    var overrideCloseCount = 0
-    var isolateCount = 0
-    var isolateCloseCount = 0
-
-    var i = 0
-    val len = text.codePointCount(0, text.length)
-    while (i < len) {
-      val codePoint = text.codePointAt(i)
-
-      if (Bidi.OVERRIDES.contains(codePoint)) {
-        overrideCount++
-      } else if (codePoint == Bidi.PDF) {
-        overrideCloseCount++
-      } else if (Bidi.ISOLATES.contains(codePoint)) {
-        isolateCount++
-      } else if (codePoint == Bidi.PDI) {
-        isolateCloseCount++
-      }
-      i++
-    }
-
-    val suffix = StringBuilder()
-
-    while (overrideCount > overrideCloseCount) {
-      suffix.appendCodePoint(Bidi.PDF)
-      overrideCloseCount++
-    }
-
-    while (isolateCount > isolateCloseCount) {
-      suffix.appendCodePoint(Bidi.FSI)
-      isolateCloseCount++
-    }
-
-    val out = StringBuilder()
-
-    return out.appendCodePoint(Bidi.FSI)
-      .append(text)
-      .append(suffix)
-      .appendCodePoint(Bidi.PDI)
-      .toString()
-  }
-
-  @JvmStatic
-  fun stripBidiProtection(text: String?): String? {
-    if (text == null) return null
-
-    return text.replace("[\\u2068\\u2069\\u202c]".toRegex(), "")
-  }
-
-  fun stripBidiIndicator(text: String): String {
-    return text.replace("\u200F", "")
-  }
-
   /**
    * Trims a [CharSequence] of starting and trailing whitespace. Behavior matches
    * [String.trim] to preserve expectations around results.
@@ -341,11 +200,6 @@ object StringUtil {
     return iterator.countBreaks()
   }
 
-  @JvmStatic
-  fun forceLtr(text: CharSequence): String {
-    return "\u202a" + text + "\u202c"
-  }
-
   @JvmStatic
   fun replace(text: CharSequence, toReplace: Char, replacement: String?): CharSequence {
     var updatedText: SpannableStringBuilder? = null