retry starting new threads

Thread.start() can throw OutOfMemoryError errors and we can attempt to
start the thread again. App developers can handle onTrimMemory and might
be cleaning up memory. While the SDK can't know if this is being done
its better to retry then to crash the app.

This commit doesn't cover all new thread, just some of the most common
ones.

Also in v5 most new threads have been migrated to Kotlin coroutines so
this patch should not be used outside of this player model branch.

Author: jkasten2

OneSignalSDK/onesignal/src/main/java/com/onesignal/OSBackgroundSync.java

@@ -27,6 +27,8 @@
 
 package com.onesignal;
 
+import static com.onesignal.OSUtils.startThreadWithRetry;
+
 import android.app.AlarmManager;
 import android.app.PendingIntent;
 import android.app.job.JobInfo;
@@ -63,7 +65,7 @@ void doBackgroundSync(Context context, Runnable runnable) {
         OneSignal.onesignalLog(OneSignal.LOG_LEVEL.DEBUG, "OSBackground sync, calling initWithContext");
         OneSignal.initWithContext(context);
         syncBgThread = new Thread(runnable, getSyncTaskThreadId());
-        syncBgThread.start();
+        startThreadWithRetry(syncBgThread);
     }
 
     boolean stopSyncBgThread() {

OneSignalSDK/onesignal/src/main/java/com/onesignal/OSUtils.java

@@ -691,4 +691,18 @@ static Throwable getRootCauseThrowable(@NonNull Throwable subjectThrowable) {
    static String getRootCauseMessage(@NonNull Throwable throwable) {
       return getRootCauseThrowable(throwable).getMessage();
    }
+
+   static void startThreadWithRetry(@NonNull Thread thread) {
+      boolean started = false;
+      while (!started) {
+         try {
+            thread.start();
+            started = true;
+         } catch (OutOfMemoryError ignored) {
+            try {
+               Thread.sleep(250);
+            } catch (InterruptedException ignoreInterrupted) {}
+         }
+      }
+   }
 }

OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignal.java

@@ -75,6 +75,7 @@
 import static com.onesignal.GenerateNotification.BUNDLE_KEY_ACTION_ID;
 import static com.onesignal.GenerateNotification.BUNDLE_KEY_ANDROID_NOTIFICATION_ID;
 import static com.onesignal.NotificationBundleProcessor.newJsonArray;
+import static com.onesignal.OSUtils.startThreadWithRetry;
 
 /**
  * The main OneSignal class - this is where you will interface with the OneSignal SDK
@@ -1488,15 +1489,16 @@ private static void registerUser() {
          return;
       }
 
-      new Thread(new Runnable() {
+      Thread thread = new Thread(new Runnable() {
          public void run() {
             try {
                registerUserTask();
             } catch(JSONException t) {
                Log(LOG_LEVEL.FATAL, "FATAL Error registering device!", t);
             }
          }
-      }, "OS_REG_USER").start();
+      }, "OS_REG_USER");
+      startThreadWithRetry(thread);
    }
 
    private static void registerUserTask() throws JSONException {

OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignalRestClient.java

@@ -27,6 +27,8 @@
 
 package com.onesignal;
 
+import static com.onesignal.OSUtils.startThreadWithRetry;
+
 import android.net.TrafficStats;
 import android.os.Build;
 import androidx.annotation.NonNull;
@@ -65,27 +67,30 @@ private static int getThreadTimeout(int timeout) {
    }
 
    public static void put(final String url, final JSONObject jsonBody, final ResponseHandler responseHandler) {
-      new Thread(new Runnable() {
+      Thread thread = new Thread(new Runnable() {
          public void run() {
             makeRequest(url, "PUT", jsonBody, responseHandler, TIMEOUT, null);
          }
-      }, "OS_REST_ASYNC_PUT").start();
+      }, "OS_REST_ASYNC_PUT");
+      startThreadWithRetry(thread);
    }
 
    public static void post(final String url, final JSONObject jsonBody, final ResponseHandler responseHandler) {
-      new Thread(new Runnable() {
+      Thread thread = new Thread(new Runnable() {
          public void run() {
             makeRequest(url, "POST", jsonBody, responseHandler, TIMEOUT, null);
          }
-      }, "OS_REST_ASYNC_POST").start();
+      }, "OS_REST_ASYNC_POST");
+      startThreadWithRetry(thread);
    }
 
    public static void get(final String url, final ResponseHandler responseHandler, @NonNull final String cacheKey) {
-      new Thread(new Runnable() {
+      Thread thread = new Thread(new Runnable() {
          public void run() {
             makeRequest(url, null, null, responseHandler, GET_TIMEOUT, cacheKey);
          }
-      }, "OS_REST_ASYNC_GET").start();
+      }, "OS_REST_ASYNC_GET");
+      startThreadWithRetry(thread);
    }
 
    public static void getSync(final String url, final ResponseHandler responseHandler, @NonNull String cacheKey) {
@@ -114,8 +119,8 @@ public void run() {
             callbackThread[0] = startHTTPConnection(url, method, jsonBody, responseHandler, timeout, cacheKey);
          }
       }, "OS_HTTPConnection");
-      
-      connectionThread.start();
+
+      startThreadWithRetry(connectionThread);
 
       // getResponseCode() can hang past it's timeout setting so join it's thread to ensure it is timing out.
       try {
@@ -129,7 +134,7 @@ public void run() {
          e.printStackTrace();
       }
    }
-   
+
    private static Thread startHTTPConnection(String url, String method, JSONObject jsonBody, ResponseHandler responseHandler, int timeout, @Nullable String cacheKey) {
       int httpResponse = -1;
       HttpURLConnection con = null;
@@ -279,7 +284,7 @@ public void run() {
             handler.onSuccess(response);
          }
       }, "OS_REST_SUCCESS_CALLBACK");
-      thread.start();
+      startThreadWithRetry(thread);
 
       return thread;
    }
@@ -293,7 +298,7 @@ public void run() {
             handler.onFailure(statusCode, response, throwable);
          }
       }, "OS_REST_FAILURE_CALLBACK");
-      thread.start();
+      startThreadWithRetry(thread);
 
       return thread;
    }