Move DownloadManager to use JobScheduler.

JobScheduler is in a much better position to coordinate tasks across
the platform to optimize battery and RAM usage.  This change removes
a bunch of manual scheduling logic by representing each download as
a separate job with relevant scheduling constraints.  Requested
network types, retry backoff timing, and newly added charging and
idle constraints are plumbed through as job parameters.

When a job times out, we halt the download and schedule it to resume
later.  The majority of downloads should have ETag values to enable
resuming like this.

Remove local wakelocks, since the platform now acquires and blames
our jobs on the requesting app.

When an active download is pushing updates to the database, check for
both paused and cancelled state to quickly halt an ongoing download.

Shift DownloadNotifier to update directly based on a Cursor, since we
no longer have the overhead of fully-parsed DownloadInfo objects.

Unify a handful of worker threads into a single shared thread.

Remove legacy "large download" activity that was thrown in the face
of the user; the UX best-practice is to go through notification, and
update that dialog to let the user override and continue if under
the hard limit.

Bug: 28098882, 26571724
Change-Id: I33ebe59b3c2ea9c89ec526f70b1950c734abc4a7

1 files changed, 21 insertions, 0 deletions

diff --git a/src/com/android/providers/downloads/DownloadScanner.java b/src/com/android/providers/downloads/DownloadScanner.java
index ca795062..37f51143 100644
--- a/src/com/android/providers/downloads/DownloadScanner.java
+++ b/src/com/android/providers/downloads/DownloadScanner.java
@@ -35,6 +35,8 @@ import com.android.internal.annotations.GuardedBy;
 import com.google.common.collect.Maps;
 
 import java.util.HashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Manages asynchronous scanning of completed downloads.
@@ -66,11 +68,26 @@ public class DownloadScanner implements MediaScannerConnectionClient {
     @GuardedBy("mConnection")
     private HashMap<String, ScanRequest> mPending = Maps.newHashMap();
 
+    private CountDownLatch mLatch;
+
     public DownloadScanner(Context context) {
         mContext = context;
         mConnection = new MediaScannerConnection(context, this);
     }
 
+    public static void requestScanBlocking(Context context, DownloadInfo info) {
+        final DownloadScanner scanner = new DownloadScanner(context);
+        scanner.mLatch = new CountDownLatch(1);
+        scanner.requestScan(info);
+        try {
+            scanner.mLatch.await(SCAN_TIMEOUT, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        } finally {
+            scanner.shutdown();
+        }
+    }
+
     /**
      * Check if requested scans are still pending. Scans may timeout after an
      * internal duration.
@@ -153,5 +170,9 @@ public class DownloadScanner implements MediaScannerConnectionClient {
             // so clean up now-orphaned media entry.
             resolver.delete(uri, null, null);
         }
+
+        if (mLatch != null) {
+            mLatch.countDown();
+        }
     }
 }