Support premature termination of listing (#928)

* Support premature termination of listing

* Added license header + small refactor

---------

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/main/java/net/schmizz/sshj/sftp/RemoteDirectory.java

@@ -15,6 +15,7 @@
  */
 package net.schmizz.sshj.sftp;
 
+import com.hierynomus.sshj.sftp.RemoteResourceSelector;
 import net.schmizz.sshj.sftp.Response.StatusCode;
 
 import java.io.IOException;
@@ -22,6 +23,8 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+import static com.hierynomus.sshj.sftp.RemoteResourceFilterConverter.selectorFrom;
+
 public class RemoteDirectory
         extends RemoteResource {
 
@@ -31,37 +34,55 @@ public class RemoteDirectory
 
     public List<RemoteResourceInfo> scan(RemoteResourceFilter filter)
             throws IOException {
-        List<RemoteResourceInfo> rri = new LinkedList<RemoteResourceInfo>();
-        // TODO: Remove GOTO! 
-        loop:
-        for (; ; ) {
-            final Response res = requester.request(newRequest(PacketType.READDIR))
-                    .retrieve(requester.getTimeoutMs(), TimeUnit.MILLISECONDS);
-            switch (res.getType()) {
+        return scan(selectorFrom(filter));
+    }
 
+    public List<RemoteResourceInfo> scan(RemoteResourceSelector selector)
+            throws IOException {
+        if (selector == null) {
+            selector = RemoteResourceSelector.ALL;
+        }
+
+        List<RemoteResourceInfo> remoteResourceInfos = new LinkedList<>();
+
+        while (true) {
+            final Response response = requester.request(newRequest(PacketType.READDIR))
+                    .retrieve(requester.getTimeoutMs(), TimeUnit.MILLISECONDS);
+
+            switch (response.getType()) {
                 case NAME:
-                    final int count = res.readUInt32AsInt();
+                    final int count = response.readUInt32AsInt();
                     for (int i = 0; i < count; i++) {
-                        final String name = res.readString(requester.sub.getRemoteCharset());
-                        res.readString(); // long name - IGNORED - shdve never been in the protocol
-                        final FileAttributes attrs = res.readFileAttributes();
+                        final String name = response.readString(requester.sub.getRemoteCharset());
+                        response.readString(); // long name - IGNORED - shdve never been in the protocol
+                        final FileAttributes attrs = response.readFileAttributes();
                         final PathComponents comps = requester.getPathHelper().getComponents(path, name);
                         final RemoteResourceInfo inf = new RemoteResourceInfo(comps, attrs);
-                        if (!(".".equals(name) || "..".equals(name)) && (filter == null || filter.accept(inf))) {
-                            rri.add(inf);
+
+                        if (".".equals(name) || "..".equals(name)) {
+                            continue;
+                        }
+
+                        final RemoteResourceSelector.Result selectionResult = selector.select(inf);
+                        switch (selectionResult) {
+                            case ACCEPT:
+                                remoteResourceInfos.add(inf);
+                                break;
+                            case CONTINUE:
+                                continue;
+                            case BREAK:
+                                return remoteResourceInfos;
                         }
                     }
                     break;
 
                 case STATUS:
-                    res.ensureStatusIs(StatusCode.EOF);
-                    break loop;
+                    response.ensureStatusIs(StatusCode.EOF);
+                    return remoteResourceInfos;
 
                 default:
-                    throw new SFTPException("Unexpected packet: " + res.getType());
+                    throw new SFTPException("Unexpected packet: " + response.getType());
             }
         }
-        return rri;
     }
-
 }

src/main/java/net/schmizz/sshj/sftp/SFTPClient.java

@@ -15,6 +15,7 @@
  */
 package net.schmizz.sshj.sftp;
 
+import com.hierynomus.sshj.sftp.RemoteResourceSelector;
 import net.schmizz.sshj.connection.channel.direct.SessionFactory;
 import net.schmizz.sshj.xfer.FilePermission;
 import net.schmizz.sshj.xfer.LocalDestFile;
@@ -25,6 +26,8 @@ import java.io.Closeable;
 import java.io.IOException;
 import java.util.*;
 
+import static com.hierynomus.sshj.sftp.RemoteResourceFilterConverter.selectorFrom;
+
 public class SFTPClient
         implements Closeable {
 
@@ -57,16 +60,18 @@ public class SFTPClient
 
     public List<RemoteResourceInfo> ls(String path)
             throws IOException {
-        return ls(path, null);
+        return ls(path, RemoteResourceSelector.ALL);
     }
 
     public List<RemoteResourceInfo> ls(String path, RemoteResourceFilter filter)
             throws IOException {
-        final RemoteDirectory dir = engine.openDir(path);
-        try {
-            return dir.scan(filter);
-        } finally {
-            dir.close();
+        return ls(path, selectorFrom(filter));
+    }
+
+    public List<RemoteResourceInfo> ls(String path, RemoteResourceSelector selector)
+            throws IOException {
+        try (RemoteDirectory dir = engine.openDir(path)) {
+            return dir.scan(selector == null ? RemoteResourceSelector.ALL : selector);
         }
     }
 

src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java

@@ -15,6 +15,7 @@
  */
 package net.schmizz.sshj.sftp;
 
+import com.hierynomus.sshj.sftp.RemoteResourceSelector;
 import net.schmizz.sshj.connection.channel.direct.SessionFactory;
 import net.schmizz.sshj.xfer.LocalDestFile;
 import net.schmizz.sshj.xfer.LocalSourceFile;
@@ -23,6 +24,8 @@ import java.io.IOException;
 import java.util.List;
 import java.util.Set;
 
+import static com.hierynomus.sshj.sftp.RemoteResourceFilterConverter.selectorFrom;
+
 public class StatefulSFTPClient
         extends SFTPClient {
 
@@ -57,7 +60,7 @@ public class StatefulSFTPClient
 
     public synchronized List<RemoteResourceInfo> ls()
             throws IOException {
-        return ls(cwd, null);
+        return ls(cwd, RemoteResourceSelector.ALL);
     }
 
     public synchronized List<RemoteResourceInfo> ls(RemoteResourceFilter filter)
@@ -70,20 +73,21 @@ public class StatefulSFTPClient
         return super.canonicalize(cwd);
     }
 
-    @Override
     public List<RemoteResourceInfo> ls(String path)
             throws IOException {
-        return ls(path, null);
+        return ls(path, RemoteResourceSelector.ALL);
+    }
+
+    public List<RemoteResourceInfo> ls(String path, RemoteResourceFilter filter)
+            throws IOException {
+        return ls(path, selectorFrom(filter));
     }
 
     @Override
-    public List<RemoteResourceInfo> ls(String path, RemoteResourceFilter filter)
+    public List<RemoteResourceInfo> ls(String path, RemoteResourceSelector selector)
             throws IOException {
-        final RemoteDirectory dir = getSFTPEngine().openDir(cwdify(path));
-        try {
-            return dir.scan(filter);
-        } finally {
-            dir.close();
+        try (RemoteDirectory dir = getSFTPEngine().openDir(cwdify(path))) {
+            return dir.scan(selector == null ? RemoteResourceSelector.ALL : selector);
         }
     }