Build a simple ANR detector.

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

@@ -303,7 +303,7 @@ class DeleteBuilderPart1(
   }
 
   fun run(): Int {
-    return db.delete(tableName, null, null)
+    return db.delete(tableName, null, emptyArray())
   }
 }
 

core-util/src/main/java/org/signal/core/util/concurrent/AnrDetector.kt

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.core.util.concurrent
+
+import android.os.Debug
+import android.os.Looper
+import androidx.annotation.MainThread
+import org.signal.core.util.ThreadUtil
+import org.signal.core.util.logging.Log
+import java.lang.IllegalStateException
+import java.lang.RuntimeException
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.seconds
+
+/**
+ * Attempts to detect ANR's by posting runnables to the main thread and detecting if they've been run within the [anrThreshold].
+ * If an ANR is detected, it is logged, and the [anrSaver] is called with the series of thread dumps that were taken of the main thread.
+ *
+ * The detection of an ANR will cause an internal user to crash.
+ */
+object AnrDetector {
+
+  private val TAG = Log.tag(AnrDetector::class.java)
+
+  private var thread: AnrDetectorThread? = null
+
+  private val dateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS zzz", Locale.US)
+
+  @JvmStatic
+  @MainThread
+  fun start(anrThreshold: Long = 5.seconds.inWholeMilliseconds, isInternal: () -> Boolean, anrSaver: (String) -> Unit) {
+    thread?.end()
+    thread = null
+
+    thread = AnrDetectorThread(anrThreshold.milliseconds, isInternal, anrSaver)
+    thread!!.start()
+  }
+
+  @JvmStatic
+  @MainThread
+  fun stop() {
+    thread?.end()
+    thread = null
+  }
+
+  private class AnrDetectorThread(
+    private val anrThreshold: Duration,
+    private val isInternal: () -> Boolean,
+    private val anrSaver: (String) -> Unit
+  ) : Thread("signal-anr") {
+
+    @Volatile
+    private var uiRan = false
+    private val uiRunnable = Runnable {
+      uiRan = true
+    }
+
+    @Volatile
+    private var stopped = false
+
+    override fun run() {
+      while (!stopped) {
+        uiRan = false
+        ThreadUtil.postToMain(uiRunnable)
+
+        val intervalCount = 5
+        val intervalDuration = anrThreshold.inWholeMilliseconds / intervalCount
+        if (intervalDuration == 0L) {
+          throw IllegalStateException("ANR threshold is too small!")
+        }
+
+        val dumps = mutableListOf<String>()
+
+        for (i in 1..intervalCount) {
+          if (stopped) {
+            Log.i(TAG, "Thread shutting down during intervals.")
+            return
+          }
+
+          ThreadUtil.sleep(intervalDuration)
+
+          if (!uiRan) {
+            dumps += getMainThreadDump()
+          } else {
+            dumps.clear()
+          }
+        }
+
+        if (!uiRan && !Debug.isDebuggerConnected() && !Debug.waitingForDebugger()) {
+          Log.w(TAG, "Failed to post to main in ${anrThreshold.inWholeMilliseconds} ms! Likely ANR!")
+
+          val dumpString = dumps.joinToString(separator = "\n\n")
+          Log.w(TAG, "Main thread dumps:\n$dumpString")
+
+          ThreadUtil.cancelRunnableOnMain(uiRunnable)
+          anrSaver(dumpString)
+
+          if (isInternal()) {
+            Log.e(TAG, "Internal user -- crashing!")
+            throw SignalAnrException()
+          }
+        }
+
+        dumps.clear()
+      }
+
+      Log.i(TAG, "Thread shutting down.")
+    }
+
+    fun end() {
+      stopped = true
+    }
+
+    private fun getMainThreadDump(): String {
+      val dump: Map<Thread, Array<StackTraceElement>> = Thread.getAllStackTraces()
+      val mainThread = Looper.getMainLooper().thread
+      val date = dateFormat.format(Date())
+      val dumpString = dump[mainThread]?.joinToString(separator = "\n") ?: "Not available."
+
+      return "--- $date:\n$dumpString"
+    }
+  }
+
+  private class SignalAnrException : RuntimeException()
+}