Fix Facsimile Hit Testing Bugs (facebook#52065)

Summary:
Pull Request resolved: facebook#52065

1. We can crash when tapping at the boundary between two spans. Previous ReactTextView had some custom heuristic for overlapping ReactTags, assuming they could be nested, which never happens (We only have a single tag per AttributedString fragment), but spans may overlap at a single character, where one is meant to be exclusive, and the other inclusive. We add logic for that.
2. We don't incorporate the offset of the text layout within the view for hit testing, needed for padding or `textAlignVertical`.

Changelog: [Internal]

Reviewed By: joevilches

Differential Revision: D76764051

Author: NickGerleman

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/PreparedLayoutTextView.kt

@@ -162,7 +162,7 @@ internal class PreparedLayoutTextView(context: Context) : ViewGroup(context), Re
     val x = event.x.toInt()
     val y = event.y.toInt()
 
-    val clickableSpan = getClickableSpanInCoords(x, y)
+    val clickableSpan = getSpanInCoords(x, y, ClickableSpan::class.java)
 
     if (clickableSpan == null) {
       clearSelection()
@@ -182,33 +182,53 @@ internal class PreparedLayoutTextView(context: Context) : ViewGroup(context), Re
     return true
   }
 
-  /**
-   * Get the clickable span that is at the exact coordinates
-   *
-   * @param x x-position of the click
-   * @param y y-position of the click
-   * @return a clickable span that's located where the click occurred, or: `null` if no clickable
-   *   span was located there
-   */
-  private fun getClickableSpanInCoords(x: Int, y: Int): ClickableSpan? {
+  private fun <T> getSpanInCoords(x: Int, y: Int, clazz: Class<T>): T? {
     val offset = getTextOffsetAt(x, y)
     if (offset < 0) {
       return null
     }
 
     val spanned = text as? Spanned ?: return null
 
-    val clickableSpans = spanned.getSpans(offset, offset, ClickableSpan::class.java)
-    if (clickableSpans.isNotEmpty()) {
-      return clickableSpans[0]
+    val spans = spanned.getSpans(offset, offset, clazz)
+    if (spans.isEmpty()) {
+      return null
+    }
+
+    // When we have multiple spans marked with SPAN_EXCLUSIVE_INCLUSIVE next to each other, both
+    // spans are returned by getSpans
+    check(spans.size <= 2)
+    for (span in spans) {
+      val spanFlags = spanned.getSpanFlags(span)
+      val inclusiveStart =
+          if ((spanFlags and Spanned.SPAN_INCLUSIVE_INCLUSIVE) != 0 ||
+              (spanFlags and Spanned.SPAN_INCLUSIVE_EXCLUSIVE) != 0) {
+            spanned.getSpanStart(span)
+          } else {
+            spanned.getSpanStart(span) + 1
+          }
+      val inclusiveEnd =
+          if ((spanFlags and Spanned.SPAN_INCLUSIVE_INCLUSIVE) != 0 ||
+              (spanFlags and Spanned.SPAN_EXCLUSIVE_INCLUSIVE) != 0) {
+            spanned.getSpanEnd(span)
+          } else {
+            spanned.getSpanEnd(span) - 1
+          }
+
+      if (offset >= inclusiveStart && offset <= inclusiveEnd) {
+        return span
+      }
     }
 
     return null
   }
 
   private fun getTextOffsetAt(x: Int, y: Int): Int {
+    val layoutX = x - paddingLeft
+    val layoutY = y - (paddingTop + (preparedLayout?.verticalOffset?.roundToInt() ?: 0))
+
     val layout = preparedLayout?.layout ?: return -1
-    val line = layout.getLineForVertical(y)
+    val line = layout.getLineForVertical(layoutY)
 
     val left: Float
     val right: Float
@@ -238,12 +258,12 @@ internal class PreparedLayoutTextView(context: Context) : ViewGroup(context), Re
       right = if (rtl) layout.getParagraphRight(line).toFloat() else layout.getLineMax(line)
     }
 
-    if (x < left || x > right) {
+    if (layoutX < left || layoutX > right) {
       return -1
     }
 
     return try {
-      layout.getOffsetForHorizontal(line, x.toFloat())
+      layout.getOffsetForHorizontal(line, layoutX.toFloat())
     } catch (e: ArrayIndexOutOfBoundsException) {
       // This happens for bidi text on Android 7-8.
       // See
@@ -332,20 +352,6 @@ internal class PreparedLayoutTextView(context: Context) : ViewGroup(context), Re
     }
   }
 
-  override fun reactTagForTouch(touchX: Float, touchY: Float): Int {
-    val offset = getTextOffsetAt(touchX.roundToInt(), touchY.roundToInt())
-    if (offset < 0) {
-      return id
-    }
-
-    val spanned = text as? Spanned ?: return id
-    val reactSpans = spanned.getSpans(offset, offset, ReactTagSpan::class.java)
-    check(reactSpans.size <= 1)
-
-    return if (reactSpans.isNotEmpty()) {
-      reactSpans[0].reactTag
-    } else {
-      id
-    }
-  }
+  override fun reactTagForTouch(touchX: Float, touchY: Float): Int =
+      getSpanInCoords(x.roundToInt(), y.roundToInt(), ReactTagSpan::class.java)?.reactTag ?: id
 }