implement resume across restart

README.md

@@ -31,5 +31,4 @@ The first time you run MuWire it will ask you to select a nickname.  This nickna
 ### Known bugs and limitations
 
 * Many UI features you would expect are not there yet
-* Downloads in progress do not get remembered between restarts
 

core/src/main/groovy/com/muwire/core/Core.groovy

@@ -191,7 +191,7 @@ public class Core {
 		eventBus.register(ResultsEvent.class, searchManager)
 		
         log.info("initializing download manager")
-        DownloadManager downloadManager = new DownloadManager(eventBus, i2pConnector, new File(home, "incompletes"), me)
+        DownloadManager downloadManager = new DownloadManager(eventBus, i2pConnector, home, me)
         eventBus.register(UIDownloadEvent.class, downloadManager)
         eventBus.register(UILoadedEvent.class, downloadManager)
         eventBus.register(FileDownloadedEvent.class, downloadManager)

core/src/main/groovy/com/muwire/core/download/DownloadManager.groovy

@@ -2,12 +2,18 @@ package com.muwire.core.download
 
 import com.muwire.core.connection.I2PConnector
 import com.muwire.core.files.FileDownloadedEvent
+import com.muwire.core.files.FileHasher
+import com.muwire.core.util.DataUtil
 
+import groovy.json.JsonBuilder
+import groovy.json.JsonOutput
+import groovy.json.JsonSlurper
 import net.i2p.data.Base64
 import net.i2p.data.Destination
 import net.i2p.util.ConcurrentHashSet
 
 import com.muwire.core.EventBus
+import com.muwire.core.InfoHash
 import com.muwire.core.Persona
 import com.muwire.core.UILoadedEvent
 
@@ -19,15 +25,16 @@ public class DownloadManager {
     private final EventBus eventBus
     private final I2PConnector connector
     private final Executor executor
-    private final File incompletes
+    private final File incompletes, home
     private final Persona me
     
     private final Set<Downloader> downloaders = new ConcurrentHashSet<>()
     
-    public DownloadManager(EventBus eventBus, I2PConnector connector, File incompletes, Persona me) {
+    public DownloadManager(EventBus eventBus, I2PConnector connector, File home, Persona me) {
         this.eventBus = eventBus
         this.connector = connector
-        this.incompletes = incompletes
+        this.incompletes = new File(home,"incompletes")
+        this.home = home
         this.me = me
         
         incompletes.mkdir()
@@ -66,14 +73,51 @@ public class DownloadManager {
     }
     
     void onUILoadedEvent(UILoadedEvent e) {
-        // TODO: load downloads here
+        File downloadsFile = new File(home, "downloads.json")
+        if (!downloadsFile.exists())
+            return
+        def slurper = new JsonSlurper()
+        downloadsFile.eachLine {
+            def json = slurper.parseText(it)
+            File file = new File(DataUtil.readi18nString(Base64.decode(json.file)))
+            def destinations = new HashSet<>()
+            json.destinations.each { destination -> 
+                destinations.add new Destination(destination)
+            }
+            byte[] hashList = Base64.decode(json.hashList)
+            InfoHash infoHash = InfoHash.fromHashList(hashList)
+            def downloader = new Downloader(eventBus, this, me, file, (long)json.length,
+                infoHash, json.pieceSizePow2, connector, destinations, incompletes)
+            downloader.download()
+            eventBus.publish(new DownloadStartedEvent(downloader : downloader))
+        }
     }
     
     void onFileDownloadedEvent(FileDownloadedEvent e) {
         downloaders.remove(e.downloader)
         persistDownloaders()
     }
+    
     private void persistDownloaders() {
-        
+        File downloadsFile = new File(home,"downloads.json")
+        downloadsFile.withPrintWriter { writer -> 
+            downloaders.each { downloader ->
+                if (!downloader.cancelled) {
+                    def json = [:]
+                    json.file = Base64.encode(DataUtil.encodei18nString(downloader.file.getAbsolutePath()))
+                    json.length = downloader.length
+                    json.pieceSizePow2 = downloader.pieceSizePow2
+                    def destinations = []
+                    downloader.destinations.each {
+                        destinations << it.toBase64()
+                    }
+                    json.destinations = destinations
+                    
+                    json.hashList = Base64.encode(downloader.infoHash.hashList)
+                    
+                    writer.println(JsonOutput.toJson(json))
+                }
+            }
+        }
     }
 }

core/src/main/groovy/com/muwire/core/download/Downloader.groovy

@@ -42,6 +42,7 @@ public class Downloader {
     private final Set<Destination> destinations
     private final int nPieces
     private final File piecesFile
+    final int pieceSizePow2
     private final Map<Destination, DownloadWorker> activeWorkers = new ConcurrentHashMap<>()
     
     
@@ -61,6 +62,7 @@ public class Downloader {
         this.connector = connector
         this.destinations = destinations
         this.piecesFile = new File(incompletes, file.getName()+".pieces")
+        this.pieceSizePow2 = pieceSizePow2
         this.pieceSize = 1 << pieceSizePow2
         
         int nPieces
@@ -88,8 +90,8 @@ public class Downloader {
     void readPieces() {
         if (!piecesFile.exists())
             return
-        piecesFile.withReader { 
+        piecesFile.eachLine { 
-            int piece = Integer.parseInt(it.readLine())
+            int piece = Integer.parseInt(it)
             downloaded.markDownloaded(piece)
         }
     }
@@ -163,11 +165,18 @@ public class Downloader {
     }
     
     public void resume() {
-        activeWorkers.each { destination, worker ->
+        destinations.each { destination ->
-            if (worker.currentState == WorkerState.FINISHED) {
+            def worker = activeWorkers.get(destination)
-                def newWorker = new DownloadWorker(destination)
+            if (worker != null) {
-                activeWorkers.put(destination, newWorker)
+                if (worker.currentState == WorkerState.FINISHED) {
-                executorService.submit(newWorker)
+                    def newWorker = new DownloadWorker(destination)
+                    activeWorkers.put(destination, newWorker)
+                    executorService.submit(newWorker)
+                }
+            } else {
+                worker = new DownloadWorker(destination)
+                activeWorkers.put(destination, worker)
+                executorService.submit(worker)
             }
         }
     }