Only schedule one job per constraint set.

app/src/main/java/org/thoughtcrime/securesms/jobmanager/Constraint.java

@@ -3,6 +3,7 @@ package org.thoughtcrime.securesms.jobmanager;
 import android.app.job.JobInfo;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 
 public interface Constraint {
@@ -14,6 +15,15 @@ public interface Constraint {
   @RequiresApi(26)
   void applyToJobInfo(@NonNull JobInfo.Builder jobInfoBuilder);
 
+  /**
+   * If you do something in {@link #applyToJobInfo} you should return something here.
+   * <p>
+   * It is sorted and concatenated with other constraints key parts to form a unique job id.
+   */
+  default @Nullable String getJobSchedulerKeyPart() {
+    return null;
+  }
+
   interface Factory<T extends Constraint> {
     T create();
   }

app/src/main/java/org/thoughtcrime/securesms/jobmanager/JobSchedulerScheduler.java

@@ -6,26 +6,23 @@ import android.app.job.JobParameters;
 import android.app.job.JobScheduler;
 import android.app.job.JobService;
 import android.content.ComponentName;
-import android.content.Context;
-import android.content.SharedPreferences;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.RequiresApi;
 
+import com.annimon.stream.Collectors;
+import com.annimon.stream.Stream;
+
 import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
 
 import java.util.List;
+import java.util.Locale;
 
 @RequiresApi(26)
-public class JobSchedulerScheduler implements Scheduler {
+public final class JobSchedulerScheduler implements Scheduler {
 
-  private static final String TAG = JobSchedulerScheduler.class.getSimpleName();
-
-  private static final String PREF_NAME    = "JobSchedulerScheduler_prefs";
-  private static final String PREF_NEXT_ID = "pref_next_id";
-
-  private static final int MAX_ID = 20;
+  private static final String TAG = Log.tag(JobSchedulerScheduler.class);
 
   private final Application application;
 
@@ -37,14 +34,23 @@ public class JobSchedulerScheduler implements Scheduler {
   @Override
   public void schedule(long delay, @NonNull List<Constraint> constraints) {
     JobScheduler jobScheduler = application.getSystemService(JobScheduler.class);
-    int          currentId    = getCurrentId();
 
-    if (constraints.isEmpty() && jobScheduler.getPendingJob(currentId) != null) {
-      Log.d(TAG, "Skipping JobScheduler enqueue because we have no constraints and there's already one pending.");
+    String constraintNames = constraints.isEmpty() ? ""
+                                                   : Stream.of(constraints)
+                                                           .map(Constraint::getJobSchedulerKeyPart)
+                                                           .withoutNulls()
+                                                           .sorted()
+                                                           .collect(Collectors.joining("-"));
+
+    int jobId = constraintNames.hashCode();
+
+    if (jobScheduler.getPendingJob(jobId) != null) {
       return;
     }
 
-    JobInfo.Builder jobInfoBuilder = new JobInfo.Builder(getAndUpdateNextId(), new ComponentName(application, SystemService.class))
+    Log.i(TAG, String.format(Locale.US, "JobScheduler enqueue of %s (%d)", constraintNames, jobId));
+
+    JobInfo.Builder jobInfoBuilder = new JobInfo.Builder(jobId, new ComponentName(application, SystemService.class))
                                                 .setMinimumLatency(delay)
                                                 .setPersisted(true);
 
@@ -55,21 +61,6 @@ public class JobSchedulerScheduler implements Scheduler {
     jobScheduler.schedule(jobInfoBuilder.build());
   }
 
-  private int getCurrentId() {
-    SharedPreferences prefs = application.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
-    return prefs.getInt(PREF_NEXT_ID, 0);
-  }
-
-  private int getAndUpdateNextId() {
-    SharedPreferences prefs      = application.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
-    int               returnedId = prefs.getInt(PREF_NEXT_ID, 0);
-    int               nextId     = returnedId + 1 > MAX_ID ? 0 : returnedId + 1;
-
-    prefs.edit().putInt(PREF_NEXT_ID, nextId).apply();
-
-    return returnedId;
-  }
-
   @RequiresApi(api = 26)
   public static class SystemService extends JobService {
 
@@ -77,6 +68,8 @@ public class JobSchedulerScheduler implements Scheduler {
     public boolean onStartJob(JobParameters params) {
       JobManager jobManager = ApplicationDependencies.getJobManager();
 
+      Log.i(TAG, "Waking due to job: " + params.getJobId());
+
       jobManager.addOnEmptyQueueListener(new JobManager.EmptyQueueListener() {
         @Override
         public void onQueueEmpty() {

app/src/main/java/org/thoughtcrime/securesms/jobmanager/impl/ChargingConstraint.java

@@ -33,6 +33,11 @@ public class ChargingConstraint implements Constraint {
     jobInfoBuilder.setRequiresCharging(true);
   }
 
+  @Override
+  public String getJobSchedulerKeyPart() {
+    return "CHARGING";
+  }
+
   public static final class Factory implements Constraint.Factory<ChargingConstraint> {
 
     @Override

app/src/main/java/org/thoughtcrime/securesms/jobmanager/impl/NetworkConstraint.java

@@ -7,6 +7,7 @@ import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 
 import org.thoughtcrime.securesms.jobmanager.Constraint;
@@ -37,6 +38,11 @@ public class NetworkConstraint implements Constraint {
     jobInfoBuilder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY);
   }
 
+  @Override
+  public String getJobSchedulerKeyPart() {
+    return "NETWORK";
+  }
+
   public static boolean isMet(@NonNull Context context) {
     ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
     NetworkInfo         activeNetworkInfo   = connectivityManager.getActiveNetworkInfo();