Make a fallback tag for listener alarms

The deprecated .set API does not allow callers to pass in a tag to
identify their listener alarms. Making a fallback with a unique format
to identify the calls from this API.

Test: Manually inspect the alarm dump.

Bug: 141785404
Change-Id: Ifacc260a53f1d3d377dc156ce3a2404cb87684cb

apex/jobscheduler/framework/java/android/app/AlarmManager.java

@@ -36,7 +36,9 @@ import android.os.Handler;
 import android.os.HandlerExecutor;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.os.Process;
 import android.os.RemoteException;
+import android.os.UserHandle;
 import android.os.WorkSource;
 import android.text.TextUtils;
 import android.util.Log;
@@ -90,6 +92,14 @@ import java.util.concurrent.Executor;
 public class AlarmManager {
     private static final String TAG = "AlarmManager";
 
+    /**
+     * Prefix used by {{@link #makeTag(long, WorkSource)}} to make a tag on behalf of the caller
+     * when the {@link #set(int, long, long, long, OnAlarmListener, Handler, WorkSource)} API is
+     * used. This prefix is a unique sequence of characters to differentiate with other tags that
+     * apps may provide to other APIs that accept a listener callback.
+     */
+    private static final String GENERATED_TAG_PREFIX = "$android.alarm.generated";
+
     /** @hide */
     @IntDef(prefix = { "RTC", "ELAPSED" }, value = {
             RTC_WAKEUP,
@@ -911,6 +921,24 @@ public class AlarmManager {
                 targetHandler, workSource, null);
     }
 
+    /**
+     * This is only used to make an identifying tag for the deprecated
+     * {@link #set(int, long, long, long, OnAlarmListener, Handler, WorkSource)} API which doesn't
+     * accept a tag. For all other APIs, the tag provided by the app is used, even if it is
+     * {@code null}.
+     */
+    private static String makeTag(long triggerMillis, WorkSource ws) {
+        final StringBuilder tagBuilder = new StringBuilder(GENERATED_TAG_PREFIX);
+
+        tagBuilder.append(":");
+        final int attributionUid =
+                (ws == null || ws.isEmpty()) ? Process.myUid() : ws.getAttributionUid();
+        tagBuilder.append(UserHandle.formatUid(attributionUid));
+        tagBuilder.append(":");
+        tagBuilder.append(triggerMillis);
+        return tagBuilder.toString();
+    }
+
     /**
      * Direct callback version of {@link #set(int, long, long, long, PendingIntent, WorkSource)}.
      * Note that repeating alarms must use the PendingIntent variant, not an OnAlarmListener.
@@ -937,8 +965,8 @@ public class AlarmManager {
     public void set(@AlarmType int type, long triggerAtMillis, long windowMillis,
             long intervalMillis, @NonNull OnAlarmListener listener, @Nullable Handler targetHandler,
             @Nullable WorkSource workSource) {
-        setImpl(type, triggerAtMillis, windowMillis, intervalMillis, 0, null, listener, null,
-                targetHandler, workSource, null);
+        setImpl(type, triggerAtMillis, windowMillis, intervalMillis, 0, null, listener,
+                makeTag(triggerAtMillis, workSource), targetHandler, workSource, null);
     }
 
     /**