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Cleaned up time estimation and file progress calculation. Constrain

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progress notification to once every 2.5 seconds in an attempt to reduce
jiggery-pokery when we're just crossing a minute's border and our transfer
rate fluctuates slightly.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1791 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Walter Korman
2002-10-08 23:42:21 +00:00
parent 1684f64408
commit ed52a5a04a
1 changed files with 86 additions and 41 deletions
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src/java/com/threerings/resource/DownloadManager.java
+86 -41
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@@ -1,5 +1,5 @@
//
// $Id: DownloadManager.java,v 1.4 2002/09/30 09:36:22 shaper Exp $
// $Id: DownloadManager.java,v 1.5 2002/10/08 23:42:21 shaper Exp $
package com.threerings.resource;
@@ -182,7 +182,7 @@ public class DownloadManager
// check the size and last-modified information for each file to
// ascertain whether our local copy needs to be refreshed
ArrayList fetch = new ArrayList();
long totalSize = 0;
ProgressInfo pinfo = new ProgressInfo();
int size = descriptors.size();
for (int ii = 0; ii < size; ii++) {
DownloadDescriptor desc = (DownloadDescriptor)descriptors.get(ii);
@@ -224,7 +224,7 @@ public class DownloadManager
(desc.destLastModified < (desc.lastModified - DELTA)) ||
(desc.destLastModified > (desc.lastModified + DELTA))) {
// increment the total file size to be fetched
totalSize += desc.fileSize;
pinfo.totalSize += desc.fileSize;
// add the file to the list of files to be fetched
fetch.add(desc);
Log.debug("File deemed stale " +
@@ -245,18 +245,11 @@ public class DownloadManager
// download all stale files
size = fetch.size();
long currentSize = 0;
long start = System.currentTimeMillis();
long bytesPerSecond = 0;
boolean complete = false;
pinfo.start = System.currentTimeMillis();
for (int ii = 0; ii < size; ii++) {
DownloadDescriptor desc = (DownloadDescriptor)fetch.get(ii);
try {
complete = processDownload(
desc, obs, currentSize, totalSize, start, bytesPerSecond);
currentSize += desc.fileSize;
bytesPerSecond = calculateXferRate(currentSize, start);
processDownload(desc, obs, pinfo);
} catch (IOException ioe) {
obs.downloadFailed(desc, ioe);
if (fragile) {
@@ -267,18 +260,16 @@ public class DownloadManager
// make sure to always let the observer know that we've wrapped up
// by reporting 100% completion
if (!complete) {
if (!pinfo.complete) {
obs.downloadProgress(100, 0L);
}
}
/**
* Processes a single download descriptor. Returns whether the
* download observer was notified of a 100% complete progress update.
* Processes a single download descriptor.
*/
protected boolean processDownload (
DownloadDescriptor desc, DownloadObserver obs, long currentSize,
long totalSize, long start, long bytesPerSecond)
protected void processDownload (
DownloadDescriptor desc, DownloadObserver obs, ProgressInfo pinfo)
throws IOException
{
// download the resource bundle from the specified URL
@@ -289,7 +280,6 @@ public class DownloadManager
InputStream in = ucon.getInputStream();
FileOutputStream out = new FileOutputStream(desc.destFile);
int read;
boolean complete = false;
// read in the file data
while ((read = in.read(_buffer)) != -1) {
@@ -297,18 +287,26 @@ public class DownloadManager
out.write(_buffer, 0, read);
// report our progress to the download observer as a
// percentage of the total file data to be transferred
currentSize += read;
int pctdone = (int)((currentSize / (float)totalSize) * 100f);
complete = (pctdone >= 100);
pinfo.currentSize += read;
int pctdone = pinfo.getPercentDone();
pinfo.complete = (pctdone >= 100);
// if we've finished downloading everything, hold off on
// notifying the observer until we're done working with the
// file to ensure that any action the observer may take with
// respect to the downloaded files can be safely undertaken
if (!complete) {
bytesPerSecond = calculateXferRate(currentSize, start);
long remaining = (bytesPerSecond == 0) ? -1 :
(totalSize - currentSize) / bytesPerSecond;
obs.downloadProgress(pctdone, remaining);
if (!pinfo.complete) {
// update the transfer rate to reflect the bit of data we
// just transferred
long now = System.currentTimeMillis();
pinfo.updateXferRate(now);
// notify the progress observer if it's been sufficiently
// long since our last notification
if ((now - pinfo.lastUpdate) >= UPDATE_DELAY) {
pinfo.lastUpdate = now;
long remaining = pinfo.getXferTimeRemaining();
obs.downloadProgress(pctdone, remaining);
}
}
}
@@ -325,24 +323,11 @@ public class DownloadManager
}
}
if (complete) {
if (pinfo.complete) {
// let the observer know we're finished now that we've
// finished all of our work with the file
obs.downloadProgress(100, 0L);
}
return complete;
}
/**
* Returns the current transfer rate in bytes per second based on
* transferring the specified quantity of data starting at the given
* time.
*/
protected long calculateXferRate (long size, long start)
{
long secs = (System.currentTimeMillis() - start) / 1000L;
return (secs == 0) ? 0 : (size / secs);
}
/**
@@ -360,6 +345,62 @@ public class DownloadManager
public boolean fragile;
}
/**
* A record detailing the progress of a download request.
*/
protected class ProgressInfo
{
/** The total file size in bytes to be transferred. */
public long totalSize;
/** The file size in bytes transferred thus far. */
public long currentSize;
/** The time at which the file transfer began. */
public long start;
/** The current transfer rate in bytes per second. */
public long bytesPerSecond;
/** The time at which the last progress update was posted to the
* progress observer. */
public long lastUpdate;
/** Whether the download has completed and the progress observer
* notified. */
public boolean complete;
/**
* Returns the percent completion, based on data size transferred,
* of the file transfer.
*/
public int getPercentDone ()
{
return (int)((currentSize / (float)totalSize) * 100f);
}
/**
* Updates the bytes per second transfer rate for the download
* associated with this progress info record.
*/
public void updateXferRate (long now)
{
long secs = (now - start) / 1000L;
bytesPerSecond = (secs == 0) ? 0 : (currentSize / secs);
}
/**
* Returns the estimated transfer time remaining for the download
* associated with this progress info record, or <code>-1</code> if
* the transfer time cannot currently be estimated.
*/
public long getXferTimeRemaining ()
{
return (bytesPerSecond == 0) ? -1 :
(totalSize - currentSize) / bytesPerSecond;
}
}
/** The downloading thread. */
protected Thread _dlthread;
@@ -376,4 +417,8 @@ public class DownloadManager
* source and destination file without considering the destination
* file to be out of date. */
protected static final long DELTA = 5000L;
/** The delay in milliseconds between notifying progress observers of
* file download progress. */
protected static final long UPDATE_DELAY = 2500L;
}