refactor(android): share UTF-16-safe truncation

steipete · steipete · commit 74386e4c7e56 · 2026-07-09T20:44:55.000+01:00
diff --git a/apps/android/app/src/main/java/ai/openclaw/app/Utf16Text.kt b/apps/android/app/src/main/java/ai/openclaw/app/Utf16Text.kt
@@ -0,0 +1,8 @@
+package ai.openclaw.app
+
+internal fun String.takeUtf16Safe(maxChars: Int): String {
+  if (length <= maxChars) return this
+  // Keep the code-unit cap without leaving a high surrogate at its boundary.
+  val endsOnHighSurrogate = maxChars > 0 && Character.isHighSurrogate(this[maxChars - 1])
+  return take(if (endsOnHighSurrogate) maxChars - 1 else maxChars)
+}
diff --git a/apps/android/app/src/main/java/ai/openclaw/app/node/DeviceNotificationListenerService.kt b/apps/android/app/src/main/java/ai/openclaw/app/node/DeviceNotificationListenerService.kt
@@ -4,6 +4,7 @@ import ai.openclaw.app.NotificationBurstLimiter
 import ai.openclaw.app.SecurePrefs
 import ai.openclaw.app.allowsPackage
 import ai.openclaw.app.isWithinQuietHours
+import ai.openclaw.app.takeUtf16Safe
 import android.app.Notification
 import android.app.NotificationManager
 import android.app.RemoteInput
@@ -30,17 +31,6 @@ internal fun sanitizeNotificationText(value: CharSequence?): String? {
   return normalized.takeUtf16Safe(MAX_NOTIFICATION_TEXT_CHARS).ifEmpty { null }
 }
 
-private fun String.takeUtf16Safe(maxChars: Int): String {
-  if (length <= maxChars) return this
-  val end =
-    if (maxChars > 0 && Character.isHighSurrogate(this[maxChars - 1])) {
-      maxChars - 1
-    } else {
-      maxChars
-    }
-  return take(end)
-}
-
 /**
  * Stable notification snapshot entry exposed through the Android notifications command.
  */
diff --git a/apps/android/app/src/main/java/ai/openclaw/app/ui/chat/ChatLinkPreview.kt b/apps/android/app/src/main/java/ai/openclaw/app/ui/chat/ChatLinkPreview.kt
@@ -1,5 +1,6 @@
 package ai.openclaw.app.ui.chat
 
+import ai.openclaw.app.takeUtf16Safe
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.util.LruCache
@@ -527,17 +528,6 @@ private fun sanitizeMetadataText(
   return sanitized.takeUtf16Safe(maxChars).takeIf(String::isNotEmpty)
 }
 
-private fun String.takeUtf16Safe(maxChars: Int): String {
-  if (length <= maxChars) return this
-  val end =
-    if (maxChars > 0 && Character.isHighSurrogate(this[maxChars - 1])) {
-      maxChars - 1
-    } else {
-      maxChars
-    }
-  return take(end)
-}
-
 private fun findTitle(html: String): String? =
   Regex("(?is)<title(?:\\s[^>]*)?>(.*?)</title\\s*>")
     .find(html)
diff --git a/apps/android/app/src/test/java/ai/openclaw/app/ui/chat/ChatLinkPreviewTest.kt b/apps/android/app/src/test/java/ai/openclaw/app/ui/chat/ChatLinkPreviewTest.kt
@@ -167,7 +167,7 @@ class ChatLinkPreviewTest {
   @Test
   fun metadataTruncationPreservesUtf16Boundaries() {
     val titlePrefix = "t".repeat(LINK_PREVIEW_TITLE_MAX_CHARS - 1)
-    val descriptionPrefix = "d".repeat(LINK_PREVIEW_DESCRIPTION_MAX_CHARS - 1)
+    val descriptionPrefix = "d".repeat(LINK_PREVIEW_DESCRIPTION_MAX_CHARS - 2)
     val result =
       parseOpenGraph(
         "<meta property='og:title' content='$titlePrefix\uD83D\uDE80 trailing'>" +
@@ -176,7 +176,7 @@ class ChatLinkPreviewTest {
       ) as LinkPreviewResult.Loaded
 
     assertEquals(titlePrefix, result.metadata.title)
-    assertEquals(descriptionPrefix, result.metadata.description)
+    assertEquals("$descriptionPrefix\uD83D\uDE80", result.metadata.description)
   }
 
   @Test
