Enforce member label emoji and text constraints.

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/MemberLabel.kt

@@ -6,6 +6,10 @@
 package org.thoughtcrime.securesms.groups.memberlabel
 
 import androidx.annotation.ColorInt
+import org.signal.core.util.BidiUtil
+import org.signal.core.util.BreakIteratorCompat
+import org.signal.core.util.StringUtil
+import org.thoughtcrime.securesms.components.emoji.EmojiUtil
 
 /**
  * A member's custom label within a group.
@@ -13,7 +17,51 @@ import androidx.annotation.ColorInt
 data class MemberLabel(
   val emoji: String?,
   val text: String
-)
+) {
+
+  /**
+   * The label text formatted for display.
+   *
+   * Use this in all rendering contexts. Use [text] only when comparing or persisting values.
+   */
+  val displayText: String get() = BidiUtil.isolateBidi(text)
+
+  companion object {
+    const val MIN_LABEL_GRAPHEMES = 1
+    const val MAX_LABEL_GRAPHEMES = 24
+    const val MAX_LABEL_BYTES = 96
+    const val MAX_EMOJI_BYTES = 48
+
+    /**
+     * Truncates label [text] to the grapheme and byte limits without any whitespace normalization.
+     */
+    @JvmStatic
+    fun truncateLabelText(text: String): String {
+      val breakIterator = BreakIteratorCompat.getInstance()
+      breakIterator.setText(text)
+      val graphemeTruncated = breakIterator.take(MAX_LABEL_GRAPHEMES).toString()
+      return StringUtil.trimToFit(graphemeTruncated, MAX_LABEL_BYTES)
+    }
+
+    /**
+     * Sanitizes and truncates label [text].
+     */
+    @JvmStatic
+    fun sanitizeLabelText(text: String): String {
+      val collapsed = StringUtil.trimToVisualBounds(text.replace(Regex("\\s+"), " "))
+      return truncateLabelText(collapsed)
+    }
+
+    /**
+     * Returns [emoji] if it is a single valid emoji within [MAX_EMOJI_BYTES], otherwise null.
+     */
+    @JvmStatic
+    fun sanitizeEmoji(emoji: String?): String? {
+      val trimmed = StringUtil.trimToFit(emoji, MAX_EMOJI_BYTES)
+      return trimmed.takeIf { it.isNotBlank() && EmojiUtil.isEmoji(it) }
+    }
+  }
+}
 
 data class StyledMemberLabel(
   val label: MemberLabel,

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/MemberLabelFragment.kt

@@ -185,7 +185,7 @@ private fun MemberLabelScreenUi(
             sender = state.recipient,
             senderNameColor = state.senderNameColor,
             labelEmoji = state.labelEmoji,
-            labelText = state.labelText,
+            labelText = state.sanitizedLabelText,
             messageText = stringResource(R.string.GroupMemberLabel__preview_sample_message)
           )
         }

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/MemberLabelPillView.kt

@@ -53,7 +53,7 @@ class MemberLabelPillView : AbstractComposeView {
     memberLabel?.let { label ->
       MemberLabelPill(
         emoji = label.emoji,
-        text = label.text,
+        text = label.displayText,
         tintColor = tintColor,
         modifier = Modifier.padding(horizontal = style.horizontalPadding, vertical = style.verticalPadding),
         textStyle = style.textStyle()

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/MemberLabelRepository.kt

@@ -68,7 +68,7 @@ class MemberLabelRepository private constructor(
 
     val aci = recipient.serviceId.orNull() as? ServiceId.ACI ?: return@withContext null
     val groupRecord = groupsTable.getGroup(groupId).orNull() ?: return@withContext null
-    return@withContext groupRecord.requireV2GroupProperties().memberLabel(aci)
+    groupRecord.requireV2GroupProperties().memberLabel(aci)?.sanitized()
   }
 
   /**
@@ -87,7 +87,7 @@ class MemberLabelRepository private constructor(
     buildMap {
       recipients.forEach { recipient ->
         val aci = recipient.serviceId.orNull() as? ServiceId.ACI
-        labelsByAci[aci]?.let { label -> put(recipient.id, label) }
+        labelsByAci[aci]?.let { label -> put(recipient.id, label.sanitized()) }
       }
     }
   }
@@ -122,6 +122,12 @@ class MemberLabelRepository private constructor(
       throw IllegalStateException("Set member label not allowed due to remote config.")
     }
 
-    GroupManager.updateMemberLabel(context, groupId, label.text, label.emoji.orEmpty())
+    val sanitizedLabel = label.sanitized()
+    GroupManager.updateMemberLabel(context, groupId, sanitizedLabel.text, sanitizedLabel.emoji.orEmpty())
   }
 }
+
+private fun MemberLabel.sanitized(): MemberLabel = this.copy(
+  emoji = MemberLabel.sanitizeEmoji(this.emoji),
+  text = MemberLabel.sanitizeLabelText(this.text)
+)

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/MemberLabelViewModel.kt

@@ -12,6 +12,7 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import org.signal.core.util.StringUtil
 import org.signal.core.util.concurrent.SignalDispatchers
 import org.thoughtcrime.securesms.conversation.colors.NameColor
 import org.thoughtcrime.securesms.groups.GroupId
@@ -19,9 +20,6 @@ import org.thoughtcrime.securesms.groups.memberlabel.MemberLabelUiState.SaveStat
 import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.recipients.RecipientId
 
-private const val MIN_LABEL_TEXT_LENGTH = 1
-private const val MAX_LABEL_TEXT_LENGTH = 24
-
 class MemberLabelViewModel(
   private val memberLabelRepo: MemberLabelRepository = MemberLabelRepository.instance,
   private val groupId: GroupId.V2,
@@ -65,11 +63,11 @@ class MemberLabelViewModel(
   }
 
   fun onLabelTextChanged(text: String) {
-    val sanitizedText = text.take(MAX_LABEL_TEXT_LENGTH)
+    val truncatedText = MemberLabel.truncateLabelText(text)
     internalUiState.update {
       it.copy(
-        labelText = sanitizedText,
-        hasChanges = hasChanges(labelEmoji = it.labelEmoji, labelText = sanitizedText)
+        labelText = truncatedText,
+        hasChanges = hasChanges(labelEmoji = it.labelEmoji, labelText = truncatedText)
       )
     }
   }
@@ -85,7 +83,7 @@ class MemberLabelViewModel(
   }
 
   private fun hasChanges(labelEmoji: String, labelText: String): Boolean {
-    return labelEmoji != originalLabelEmoji || labelText != originalLabelText
+    return labelEmoji != originalLabelEmoji || MemberLabel.sanitizeLabelText(labelText) != originalLabelText
   }
 
   fun save() {
@@ -128,13 +126,16 @@ data class MemberLabelUiState(
   val hasChanges: Boolean = false,
   val saveState: SaveState? = null
 ) {
+  val sanitizedLabelText: String get() = MemberLabel.sanitizeLabelText(labelText)
+
   val remainingCharacters: Int
-    get() = MAX_LABEL_TEXT_LENGTH - labelText.length
+    get() = MemberLabel.MAX_LABEL_GRAPHEMES - StringUtil.getGraphemeCount(sanitizedLabelText)
 
   val isSaveEnabled: Boolean
     get() {
-      val isCleared = labelText.isEmpty() && labelEmoji.isEmpty()
-      val hasValidLabel = labelText.length in MIN_LABEL_TEXT_LENGTH..MAX_LABEL_TEXT_LENGTH
+      val isCleared = sanitizedLabelText.isEmpty() && labelEmoji.isEmpty()
+      val graphemeCount = StringUtil.getGraphemeCount(sanitizedLabelText)
+      val hasValidLabel = graphemeCount in MemberLabel.MIN_LABEL_GRAPHEMES..MemberLabel.MAX_LABEL_GRAPHEMES
       return hasChanges && (hasValidLabel || isCleared) && saveState != SaveState.InProgress
     }
 

app/src/main/java/org/thoughtcrime/securesms/groups/memberlabel/SenderNameWithLabel.kt

@@ -48,7 +48,7 @@ fun SenderNameWithLabel(
     labelSlot = { label ->
       MemberLabelPill(
         emoji = label.emoji,
-        text = label.text,
+        text = label.displayText,
         tintColor = senderColor,
         modifier = defaultLabelModifier,
         textStyle = defaultLabelTextStyle()
@@ -78,7 +78,7 @@ fun SenderNameWithLabel(
     labelSlot = { label ->
       MemberLabelPill(
         emoji = label.emoji,
-        text = label.text,
+        text = label.displayText,
         textColor = labelTextColor,
         backgroundColor = labelBackgroundColor,
         modifier = defaultLabelModifier,

app/src/main/java/org/thoughtcrime/securesms/recipients/ui/about/AboutSheet.kt

@@ -381,7 +381,7 @@ private fun MemberLabelRow(
         }
 
         Text(
-          text = memberLabel.text,
+          text = memberLabel.displayText,
           style = MaterialTheme.typography.bodyLarge,
           maxLines = 1,
           overflow = TextOverflow.Ellipsis,