perf(replay): Use hash set for mask view class lookups (#6410)

* perf(replay): Use hash set for mask view class lookups

maskViewClasses and unmaskViewClasses were backed by a
CopyOnWriteArraySet, whose contains() is a linear scan. The view
hierarchy traversal checks both sets for every superclass of every
view on the main thread, so capture cost grew with the size of the
configured class lists.

Back both sets with a ConcurrentHashMap key set for O(1) lookups
while keeping thread-safe, non-throwing iteration.

Co-Authored-By: Roman Zavarnitsyn <roman.zavarnitsyn@sentry.io>

* changelog

Co-Authored-By: Roman Zavarnitsyn <roman.zavarnitsyn@sentry.io>

* fix(replay): Ignore null mask view class names

ConcurrentHashMap-backed sets reject null keys, while the previous
CopyOnWriteArraySet accepted them. Hybrid SDKs (e.g. React Native via
ReadableArray.getString) can pass null despite the @NotNull annotation,
which would now throw during SDK init.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: Roman Zavarnitsyn <roman.zavarnitsyn@sentry.io>
Co-authored-by: Roman Zavarnitsyn <rom4ek93@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: 3 people

CHANGELOG.md

@@ -7,6 +7,10 @@
 - Added `Environment` to the `Scope`, allowing you to overwrite the `Environment` set on the options ([#5772](https://github.com/getsentry/sentry-java/pull/5772))
   - The scope `Environment` is also applied to the trace envelope header (DSC), logs, metrics and profiles, so all telemetry of a trace reports the same environment
 
+### Improvements
+
+- Speed up Session Replay and screenshot masking for large `maskViewClasses`/`unmaskViewClasses` lists by using constant-time class lookups ([#6410](https://github.com/getsentry/sentry-java/pull/6410))
+
 ### Fixes
 
 - Keep UI profiling running when `startProfiler` is called before a requested stop takes effect at the end of the current chunk ([#6291](https://github.com/getsentry/sentry-java/pull/6291))

sentry-android-replay/src/test/java/io/sentry/android/replay/capture/SessionCaptureStrategyTest.kt

@@ -46,7 +46,6 @@ import java.util.concurrent.ScheduledExecutorService
 import java.util.concurrent.TimeUnit.MILLISECONDS
 import java.util.concurrent.TimeUnit.SECONDS
 import kotlin.test.Test
-import kotlin.test.assertContentEquals
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
 import kotlin.test.assertNull
@@ -696,8 +695,8 @@ class SessionCaptureStrategyTest {
           assertEquals(true, optionsEvent[0].optionsPayload["maskAllText"])
           assertEquals(false, optionsEvent[0].optionsPayload["maskAllImages"])
           assertEquals("high", optionsEvent[0].optionsPayload["quality"])
-          assertContentEquals(
-            listOf(
+          assertThat(optionsEvent[0].optionsPayload["maskedViewClasses"] as Collection<*>)
+            .containsExactly(
               "android.widget.TextView",
               "android.webkit.WebView",
               "android.widget.VideoView",
@@ -706,13 +705,9 @@ class SessionCaptureStrategyTest {
               "com.google.android.exoplayer2.ui.PlayerView",
               "com.google.android.exoplayer2.ui.StyledPlayerView",
               "my.custom.View",
-            ),
-            optionsEvent[0].optionsPayload["maskedViewClasses"] as Collection<*>,
-          )
-          assertContentEquals(
-            listOf("android.widget.ImageView"),
-            optionsEvent[0].optionsPayload["unmaskedViewClasses"] as Collection<*>,
-          )
+            )
+          assertThat(optionsEvent[0].optionsPayload["unmaskedViewClasses"] as Collection<*>)
+            .containsExactly("android.widget.ImageView")
         },
       )
   }

sentry/src/main/java/io/sentry/SentryMaskingOptions.java

@@ -1,7 +1,8 @@
 package io.sentry;
 
+import java.util.Collections;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.ConcurrentHashMap;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -32,7 +33,7 @@ public abstract class SentryMaskingOptions {
    *
    * <p>Default is empty.
    */
-  protected Set<String> maskViewClasses = new CopyOnWriteArraySet<>();
+  protected Set<String> maskViewClasses = Collections.newSetFromMap(new ConcurrentHashMap<>());
 
   /**
    * Ignore all views with the specified class names from masking. The class name is the fully
@@ -44,7 +45,7 @@ public abstract class SentryMaskingOptions {
    *
    * <p>Default is empty.
    */
-  protected Set<String> unmaskViewClasses = new CopyOnWriteArraySet<>();
+  protected Set<String> unmaskViewClasses = Collections.newSetFromMap(new ConcurrentHashMap<>());
 
   /** The class name of the view container that masks all of its children. */
   protected @Nullable String maskViewContainerClass = null;
@@ -92,6 +93,10 @@ public Set<String> getMaskViewClasses() {
   }
 
   public void addMaskViewClass(final @NotNull String className) {
+    // Hybrid SDKs may pass null despite the annotation, and the backing set rejects null keys
+    if (className == null) {
+      return;
+    }
     this.maskViewClasses.add(className);
     this.unmaskViewClasses.remove(className);
   }
@@ -102,6 +107,10 @@ public Set<String> getUnmaskViewClasses() {
   }
 
   public void addUnmaskViewClass(final @NotNull String className) {
+    // Hybrid SDKs may pass null despite the annotation, and the backing set rejects null keys
+    if (className == null) {
+      return;
+    }
     this.unmaskViewClasses.add(className);
     this.maskViewClasses.remove(className);
   }

sentry/src/test/java/io/sentry/SentryMaskingOptionsTest.kt

@@ -40,6 +40,26 @@ class SentryMaskingOptionsTest {
     assertTrue(options.unmaskViewClasses.contains("com.example.MyView"))
   }
 
+  @Test
+  fun `addMaskViewClass ignores null`() {
+    val options = TestMaskingOptions()
+    SentryMaskingOptions::class
+      .java
+      .getMethod("addMaskViewClass", String::class.java)
+      .invoke(options, null)
+    assertTrue(options.maskViewClasses.isEmpty())
+  }
+
+  @Test
+  fun `addUnmaskViewClass ignores null`() {
+    val options = TestMaskingOptions()
+    SentryMaskingOptions::class
+      .java
+      .getMethod("addUnmaskViewClass", String::class.java)
+      .invoke(options, null)
+    assertTrue(options.unmaskViewClasses.isEmpty())
+  }
+
   @Test
   fun `setMaskAllText true adds TextView to maskViewClasses`() {
     val options = TestMaskingOptions()