--- /dev/null
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2018 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.net;
+
+import java.io.File;
+import java.io.IOException;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import com.threerings.getdown.data.Resource;
+
+import static com.threerings.getdown.Log.log;
+
+/**
+ * Handles the download of a collection of files, first issuing HTTP head requests to obtain size
+ * information and then downloading the files individually, reporting progress back via protected
+ * callback methods. <em>Note:</em> these methods are all called arbitrary download threads, so
+ * implementors must take care to only execute thread-safe code or simply pass a message to the AWT
+ * thread, for example.
+ */
+public abstract class Downloader
+{
+ /**
+ * Start the downloading process.
+ * @param resources the resources to download.
+ * @param maxConcurrent the maximum number of concurrent downloads allowed.
+ * @return true if the download completed, false if it was aborted (via {@link #abort}).
+ */
+ public boolean download (Collection<Resource> resources, int maxConcurrent)
+ {
+ // first compute the total size of our download
+ resolvingDownloads();
+ for (Resource rsrc : resources) {
+ try {
+ _sizes.put(rsrc, Math.max(checkSize(rsrc), 0L));
+ } catch (IOException ioe) {
+ downloadFailed(rsrc, ioe);
+ }
+ }
+
+ long totalSize = sum(_sizes.values());
+ log.info("Downloading " + resources.size() + " resources",
+ "totalBytes", totalSize, "maxConcurrent", maxConcurrent);
+
+ // make a note of the time at which we started the download
+ _start = System.currentTimeMillis();
+
+ // start the downloads
+ ExecutorService exec = Executors.newFixedThreadPool(maxConcurrent);
+ for (final Resource rsrc : resources) {
+ // make sure the resource's target directory exists
+ File parent = new File(rsrc.getLocal().getParent());
+ if (!parent.exists() && !parent.mkdirs()) {
+ log.warning("Failed to create target directory for resource '" + rsrc + "'.");
+ }
+
+ exec.execute(new Runnable() {
+ @Override public void run () {
+ try {
+ if (_state != State.ABORTED) {
+ download(rsrc);
+ }
+ } catch (IOException ioe) {
+ _state = State.FAILED;
+ downloadFailed(rsrc, ioe);
+ }
+ }
+ });
+ }
+ exec.shutdown();
+
+ // wait for the downloads to complete
+ try {
+ exec.awaitTermination(10, TimeUnit.DAYS);
+
+ // report download completion if we did not already do so via our final resource
+ if (_state == State.DOWNLOADING) {
+ downloadProgress(100, 0);
+ }
+
+ } catch (InterruptedException ie) {
+ exec.shutdownNow();
+ downloadFailed(null, ie);
+ }
+
+ return _state != State.ABORTED;
+ }
+
+ /**
+ * Aborts the in-progress download.
+ */
+ public void abort () {
+ _state = State.ABORTED;
+ }
+
+ /**
+ * Called before the downloader begins the series of HTTP head requests to determine the
+ * size of the files it needs to download.
+ */
+ protected void resolvingDownloads () {}
+
+ /**
+ * Reports ongoing progress toward completion of the overall downloading task. One call is
+ * guaranteed to be made reporting 100% completion if the download is not aborted and no
+ * resources fail.
+ *
+ * @param percent the percent completion of the complete download process (based on total bytes
+ * downloaded versus total byte size of all resources).
+ * @param remaining the estimated download time remaining in seconds, or {@code -1} if the time
+ * can not yet be determined.
+ */
+ protected void downloadProgress (int percent, long remaining) {}
+
+ /**
+ * Called if a failure occurs while downloading a resource. No progress will be reported after
+ * a download fails, but additional download failures may be reported.
+ *
+ * @param rsrc the resource that failed to download, or null if the download failed due to
+ * thread interruption.
+ * @param cause the exception detailing the failure.
+ */
+ protected void downloadFailed (Resource rsrc, Exception cause) {}
+
+ /**
+ * Performs the protocol-specific portion of checking download size.
+ */
+ protected abstract long checkSize (Resource rsrc) throws IOException;
+
+ /**
+ * Periodically called by the protocol-specific downloaders to update their progress. This
+ * should be called at least once for each resource to be downloaded, with the total downloaded
+ * size for that resource. It can also be called periodically along the way for each resource
+ * to communicate incremental progress.
+ *
+ * @param rsrc the resource currently being downloaded.
+ * @param currentSize the number of bytes currently downloaded for said resource.
+ * @param actualSize the size reported for this resource now that we're actually downloading
+ * it. Some web servers lie about Content-length when doing a HEAD request, so by reporting
+ * updated sizes here we can recover from receiving bogus information in the earlier
+ * {@link #checkSize} phase.
+ */
+ protected synchronized void reportProgress (Resource rsrc, long currentSize, long actualSize)
+ {
+ // update the actual size for this resource (but don't let it shrink)
+ _sizes.put(rsrc, actualSize = Math.max(actualSize, _sizes.get(rsrc)));
+
+ // update the current downloaded size for said resource; don't allow the downloaded bytes
+ // to exceed the original claimed size of the resource, otherwise our progress will get
+ // booched and we'll end up back on the Daily WTF: http://tinyurl.com/29wt4oq
+ _downloaded.put(rsrc, Math.min(actualSize, currentSize));
+
+ // notify the observer if it's been sufficiently long since our last notification
+ long now = System.currentTimeMillis();
+ if ((now - _lastUpdate) >= UPDATE_DELAY) {
+ _lastUpdate = now;
+
+ // total up our current and total bytes
+ long downloaded = sum(_downloaded.values());
+ long totalSize = sum(_sizes.values());
+
+ // compute our bytes per second
+ long secs = (now - _start) / 1000L;
+ long bps = (secs == 0) ? 0 : (downloaded / secs);
+
+ // compute our percentage completion
+ int pctdone = (totalSize == 0) ? 0 : (int)((downloaded * 100f) / totalSize);
+
+ // estimate our time remaining
+ long remaining = (bps <= 0 || totalSize == 0) ? -1 : (totalSize - downloaded) / bps;
+
+ // if we're complete or failed, when we don't want to report again
+ if (_state == State.DOWNLOADING) {
+ if (pctdone == 100) _state = State.COMPLETE;
+ downloadProgress(pctdone, remaining);
+ }
+ }
+ }
+
+ /**
+ * Sums the supplied values.
+ */
+ protected static long sum (Iterable<Long> values)
+ {
+ long acc = 0L;
+ for (Long value : values) {
+ acc += value;
+ }
+ return acc;
+ }
+
+ protected enum State { DOWNLOADING, COMPLETE, FAILED, ABORTED }
+
+ /**
+ * Accomplishes the copying of the resource from remote location to local location using
+ * protocol-specific code. This method should periodically check whether {@code _state} is set
+ * to aborted and abort any in-progress download if so.
+ */
+ protected abstract void download (Resource rsrc) throws IOException;
+
+ /** The reported sizes of our resources. */
+ protected Map<Resource, Long> _sizes = new HashMap<>();
+
+ /** The bytes downloaded for each resource. */
+ protected Map<Resource, Long> _downloaded = new HashMap<>();
+
+ /** The time at which the file transfer began. */
+ protected long _start;
+
+ /** The current transfer rate in bytes per second. */
+ protected long _bytesPerSecond;
+
+ /** The time at which the last progress update was posted to the progress observer. */
+ protected long _lastUpdate;
+
+ /** A wee state machine to ensure we call our callbacks sanely. */
+ protected volatile State _state = State.DOWNLOADING;
+
+ /** The delay in milliseconds between notifying progress observers of file download
+ * progress. */
+ protected static final long UPDATE_DELAY = 500L;
+}
git://source.jalview.org / jalview.git / blobdiff