From fec5f50a85e1bfc7bb4fa12d04ffa7526c79fad7 Mon Sep 17 00:00:00 2001
From: Jeff Sharkey <jsharkey@android.com>
Date: Wed, 28 Nov 2012 14:35:40 -0800
Subject: Improve download remaining time calculation.

Calculate remaining time in DownloadNotifier so we always use the
most recent progress data, which avoids showing stale times.

Weight speed calculation to prefer historical data so remaining time
is smoother on bumpy network connections.

Bug: 7631948
Change-Id: I497be0899e65086356745340b19d3987c6185bdd
---
 src/com/android/providers/downloads/DownloadHandler.java | 16 ++++++----------
 .../android/providers/downloads/DownloadNotifier.java    | 11 ++++++-----
 src/com/android/providers/downloads/DownloadThread.java  | 13 ++-----------
 3 files changed, 14 insertions(+), 26 deletions(-)

(limited to 'src')

diff --git a/src/com/android/providers/downloads/DownloadHandler.java b/src/com/android/providers/downloads/DownloadHandler.java
index dff09eb0..2f02864e 100644
--- a/src/com/android/providers/downloads/DownloadHandler.java
+++ b/src/com/android/providers/downloads/DownloadHandler.java
@@ -37,7 +37,7 @@ public class DownloadHandler {
     private final HashMap<Long, DownloadInfo> mDownloadsInProgress =
             new HashMap<Long, DownloadInfo>();
     @GuardedBy("this")
-    private final LongSparseArray<Long> mRemainingMillis = new LongSparseArray<Long>();
+    private final LongSparseArray<Long> mCurrentSpeed = new LongSparseArray<Long>();
 
     private final int mMaxConcurrentDownloadsAllowed = Resources.getSystem().getInteger(
             com.android.internal.R.integer.config_MaxConcurrentDownloadsAllowed);
@@ -82,23 +82,19 @@ public class DownloadHandler {
 
     public synchronized void dequeueDownload(long id) {
         mDownloadsInProgress.remove(id);
-        mRemainingMillis.remove(id);
+        mCurrentSpeed.remove(id);
         startDownloadThreadLocked();
         if (mDownloadsInProgress.size() == 0 && mDownloadsQueue.size() == 0) {
             notifyAll();
         }
     }
 
-    public synchronized void setRemainingMillis(long id, long millis) {
-        mRemainingMillis.put(id, millis);
+    public synchronized void setCurrentSpeed(long id, long speed) {
+        mCurrentSpeed.put(id, speed);
     }
 
-    /**
-     * Return remaining time until given {@link DownloadInfo} finishes, in
-     * milliseconds, or -1 if unknown.
-     */
-    public synchronized long getRemainingMillis(long id) {
-        return mRemainingMillis.get(id, -1L);
+    public synchronized long getCurrentSpeed(long id) {
+        return mCurrentSpeed.get(id, -1L);
     }
 
     // right now this is only used by tests. but there is no reason why it can't be used
diff --git a/src/com/android/providers/downloads/DownloadNotifier.java b/src/com/android/providers/downloads/DownloadNotifier.java
index f6e7a2ee..f89d2d02 100644
--- a/src/com/android/providers/downloads/DownloadNotifier.java
+++ b/src/com/android/providers/downloads/DownloadNotifier.java
@@ -163,23 +163,24 @@ public class DownloadNotifier {
 
                 long current = 0;
                 long total = 0;
-                long remainingMillis = -1;
+                long speed = 0;
                 for (DownloadInfo info : cluster) {
                     if (info.mTotalBytes != -1) {
                         current += info.mCurrentBytes;
                         total += info.mTotalBytes;
-                        remainingMillis = Math.max(
-                                handler.getRemainingMillis(info.mId), remainingMillis);
+                        speed += handler.getCurrentSpeed(info.mId);
                     }
                 }
 
                 if (total > 0) {
                     final int percent = (int) ((current * 100) / total);
-                    if (remainingMillis != -1) {
+                    percentText = res.getString(R.string.download_percent, percent);
+
+                    if (speed > 0) {
+                        final long remainingMillis = ((total - current) * 1000) / speed;
                         remainingText = res.getString(R.string.download_remaining,
                                 DateUtils.formatDuration(remainingMillis));
                     }
-                    percentText = res.getString(R.string.download_percent, percent);
 
                     builder.setProgress(100, percent, false);
                 } else {
diff --git a/src/com/android/providers/downloads/DownloadThread.java b/src/com/android/providers/downloads/DownloadThread.java
index 2bd3d362..34bc8e34 100644
--- a/src/com/android/providers/downloads/DownloadThread.java
+++ b/src/com/android/providers/downloads/DownloadThread.java
@@ -107,8 +107,6 @@ public class DownloadThread extends Thread {
         public long mSpeedSampleStart;
         /** Bytes transferred since current sample started. */
         public long mSpeedSampleBytes;
-        /** Estimated time until finished. */
-        public long mRemainingMillis;
 
         public State(DownloadInfo info) {
             mMimeType = Intent.normalizeMimeType(info.mMimeType);
@@ -443,20 +441,13 @@ public class DownloadThread extends Thread {
             if (state.mSpeed == 0) {
                 state.mSpeed = sampleSpeed;
             } else {
-                state.mSpeed = (state.mSpeed + sampleSpeed) / 2;
+                state.mSpeed = ((state.mSpeed * 3) + sampleSpeed) / 4;
             }
 
             state.mSpeedSampleStart = now;
             state.mSpeedSampleBytes = state.mCurrentBytes;
 
-            if (state.mSpeed != 0) {
-                state.mRemainingMillis = ((state.mTotalBytes - state.mCurrentBytes) * 1000)
-                        / state.mSpeed;
-            } else {
-                state.mRemainingMillis = -1;
-            }
-
-            DownloadHandler.getInstance().setRemainingMillis(mInfo.mId, state.mRemainingMillis);
+            DownloadHandler.getInstance().setCurrentSpeed(mInfo.mId, state.mSpeed);
         }
 
         if (state.mCurrentBytes - state.mBytesNotified > Constants.MIN_PROGRESS_STEP &&
-- 
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