HADOOP-14169. Implement listStatusIterator, listLocatedStatus for ViewFs. Contributed by Erik Krogen.

(cherry picked from commit e1a99802fc)

Conflicts:
	hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFs.java
	hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/viewfs/ViewFsBaseTest.java

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -34,6 +34,9 @@ Release 2.7.4 - UNRELEASED
     HADOOP-14138. Remove S3A ref from META-INF service discovery, rely on
     existing core-default entry (Steve Loughran via jlowe)
 
+    HADOOP-14169. Implement listStatusIterator, listLocatedStatus for ViewFs.
+    (Erik Krogen via shv)
+
   BUG FIXES
 
     HADOOP-13362. DefaultMetricsSystem leaks the source name when a source

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ChRootedFs.java

@@ -35,8 +35,10 @@ import org.apache.hadoop.fs.FileChecksum;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FsServerDefaults;
 import org.apache.hadoop.fs.FsStatus;
+import org.apache.hadoop.fs.LocatedFileStatus;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.UnresolvedLinkException;
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.AclEntry;
@@ -234,6 +236,18 @@ class ChRootedFs extends AbstractFileSystem {
     return myFs.listStatus(fullPath(f));
   }
 
+  @Override
+  public RemoteIterator<FileStatus> listStatusIterator(final Path f)
+    throws IOException, UnresolvedLinkException {
+    return myFs.listStatusIterator(fullPath(f));
+  }
+
+  @Override
+  public RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f)
+      throws IOException, UnresolvedLinkException {
+    return myFs.listLocatedStatus(fullPath(f));
+  }
+
   @Override
   public void mkdir(final Path dir, final FsPermission permission,
       final boolean createParent) throws IOException, UnresolvedLinkException {

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFs.java

@@ -43,6 +43,7 @@ import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FsConstants;
 import org.apache.hadoop.fs.FsServerDefaults;
 import org.apache.hadoop.fs.FsStatus;
+import org.apache.hadoop.fs.LocatedFileStatus;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.fs.ParentNotDirectoryException;
 import org.apache.hadoop.fs.Path;
@@ -388,25 +389,31 @@ public class ViewFs extends AbstractFileSystem {
       return fsIter;
     }
 
-    return new RemoteIterator<FileStatus>() {
-      final RemoteIterator<FileStatus> myIter;
-      final ChRootedFs targetFs;
-      { // Init
-          myIter = fsIter;
-          targetFs = (ChRootedFs) res.targetFileSystem;
+    return new WrappingRemoteIterator<FileStatus>(res, fsIter, f) {
+      @Override
+      public FileStatus getViewFsFileStatus(FileStatus stat, Path newPath) {
+        return new ViewFsFileStatus(stat, newPath);
+      }
+    };
   }
 
   @Override
-      public boolean hasNext() throws IOException {
-        return myIter.hasNext();
+  public RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f)
+      throws AccessControlException, FileNotFoundException,
+      UnresolvedLinkException, IOException {
+    final InodeTree.ResolveResult<AbstractFileSystem> res =
+        fsState.resolve(getUriPath(f), true);
+    final RemoteIterator<LocatedFileStatus> fsIter =
+        res.targetFileSystem.listLocatedStatus(res.remainingPath);
+    if (res.isInternalDir()) {
+      return fsIter;
     }
 
+    return new WrappingRemoteIterator<LocatedFileStatus>(res, fsIter, f) {
       @Override
-      public FileStatus next() throws IOException {
-        FileStatus status =  myIter.next();
-        String suffix = targetFs.stripOutRoot(status.getPath());
-        return new ViewFsFileStatus(status, makeQualified(
-            suffix.length() == 0 ? f : new Path(res.resolvedPath, suffix)));
+      public LocatedFileStatus getViewFsFileStatus(LocatedFileStatus stat,
+          Path newPath) {
+        return new ViewFsLocatedFileStatus(stat, newPath);
       }
     };
   }
@@ -717,6 +724,41 @@ public class ViewFs extends AbstractFileSystem {
     res.targetFileSystem.removeXAttr(res.remainingPath, name);
   }
 
+  /**
+   * Helper class to perform some transformation on results returned
+   * from a RemoteIterator.
+   */
+  private abstract class WrappingRemoteIterator<T extends FileStatus>
+      implements RemoteIterator<T> {
+    private final String resolvedPath;
+    private final ChRootedFs targetFs;
+    private final RemoteIterator<T> innerIter;
+    private final Path originalPath;
+
+    WrappingRemoteIterator(InodeTree.ResolveResult<AbstractFileSystem> res,
+        RemoteIterator<T> innerIter, Path originalPath) {
+      this.resolvedPath = res.resolvedPath;
+      this.targetFs = (ChRootedFs)res.targetFileSystem;
+      this.innerIter = innerIter;
+      this.originalPath = originalPath;
+    }
+
+    @Override
+    public boolean hasNext() throws IOException {
+      return innerIter.hasNext();
+    }
+
+    @Override
+    public T next() throws IOException {
+      T status =  innerIter.next();
+      String suffix = targetFs.stripOutRoot(status.getPath());
+      Path newPath = makeQualified(suffix.length() == 0 ? originalPath
+          : new Path(resolvedPath, suffix));
+      return getViewFsFileStatus(status, newPath);
+    }
+
+    protected abstract T getViewFsFileStatus(T status, Path newPath);
+  }
 
   /*
    * An instance of this class represents an internal dir of the viewFs 

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/viewfs/ViewFsBaseTest.java

@@ -25,18 +25,29 @@ import static org.apache.hadoop.fs.FileContextTestHelper.isFile;
 import static org.apache.hadoop.fs.viewfs.Constants.PERMISSION_555;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyBoolean;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.AbstractFileSystem;
 import org.apache.hadoop.fs.BlockLocation;
 import org.apache.hadoop.fs.FileContext;
 import org.apache.hadoop.fs.FileContextTestHelper;
+import org.apache.hadoop.fs.LocatedFileStatus;
 import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.FileContextTestHelper.fileType;
 import org.apache.hadoop.fs.FileStatus;
@@ -54,7 +65,6 @@ import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.Mockito;
 
 
 /**
@@ -317,6 +327,16 @@ public class ViewFsBaseTest {
       }
     }
     Assert.assertTrue(dirFooPresent);
+    RemoteIterator<LocatedFileStatus> dirLocatedContents =
+        fcView.listLocatedStatus(new Path("/targetRoot/"));
+    dirFooPresent = false;
+    while (dirLocatedContents.hasNext()) {
+      FileStatus fileStatus = dirLocatedContents.next();
+      if (fileStatus.getPath().getName().equals("dirFoo")) {
+        dirFooPresent = true;
+      }
+    }
+    Assert.assertTrue(dirFooPresent);
   }
   
   // rename across mount points that point to same target also fail 
@@ -448,24 +468,23 @@ public class ViewFsBaseTest {
   }
   
   @Test
-  public void testGetFileChecksum() throws AccessControlException
-    , UnresolvedLinkException, IOException {
-    AbstractFileSystem mockAFS = Mockito.mock(AbstractFileSystem.class);
+  public void testGetFileChecksum() throws AccessControlException,
+      UnresolvedLinkException, IOException {
+    AbstractFileSystem mockAFS = mock(AbstractFileSystem.class);
     InodeTree.ResolveResult<AbstractFileSystem> res =
       new InodeTree.ResolveResult<AbstractFileSystem>(null, mockAFS , null,
         new Path("someFile"));
     @SuppressWarnings("unchecked")
-    InodeTree<AbstractFileSystem> fsState = Mockito.mock(InodeTree.class);
-    Mockito.when(fsState.resolve(Mockito.anyString()
-      , Mockito.anyBoolean())).thenReturn(res);
-    ViewFs vfs = Mockito.mock(ViewFs.class);
+    InodeTree<AbstractFileSystem> fsState = mock(InodeTree.class);
+    when(fsState.resolve(anyString(), anyBoolean())).thenReturn(res);
+    ViewFs vfs = mock(ViewFs.class);
     vfs.fsState = fsState;
 
-    Mockito.when(vfs.getFileChecksum(new Path("/tmp/someFile")))
+    when(vfs.getFileChecksum(new Path("/tmp/someFile")))
       .thenCallRealMethod();
     vfs.getFileChecksum(new Path("/tmp/someFile"));
 
-    Mockito.verify(mockAFS).getFileChecksum(new Path("someFile"));
+    verify(mockAFS).getFileChecksum(new Path("someFile"));
   }
 
   @Test(expected=FileNotFoundException.class) 
@@ -777,4 +796,58 @@ public class ViewFsBaseTest {
   public void testInternalRemoveXAttr() throws IOException {
     fcView.removeXAttr(new Path("/internalDir"), "xattrName");
   }
+
+  // Confirm that listLocatedStatus is delegated properly to the underlying
+  // AbstractFileSystem to allow for optimizations
+  @Test
+  public void testListLocatedStatus() throws IOException {
+    final Path mockTarget = new Path("mockfs://listLocatedStatus/foo");
+    final Path mountPoint = new Path("/fooMount");
+    final Configuration newConf = new Configuration();
+    newConf.setClass("fs.AbstractFileSystem.mockfs.impl", MockFs.class,
+        AbstractFileSystem.class);
+    ConfigUtil.addLink(newConf, mountPoint.toString(), mockTarget.toUri());
+    FileContext.getFileContext(URI.create("viewfs:///"), newConf)
+        .listLocatedStatus(mountPoint);
+    AbstractFileSystem mockFs = MockFs.getMockFs(mockTarget.toUri());
+    verify(mockFs).listLocatedStatus(new Path(mockTarget.toUri().getPath()));
+    verify(mockFs, never()).listStatus(any(Path.class));
+    verify(mockFs, never()).listStatusIterator(any(Path.class));
+  }
+
+  // Confirm that listStatus is delegated properly to the underlying
+  // AbstractFileSystem's listStatusIterator to allow for optimizations
+  @Test
+  public void testListStatusIterator() throws IOException {
+    final Path mockTarget = new Path("mockfs://listStatusIterator/foo");
+    final Path mountPoint = new Path("/fooMount");
+    final Configuration newConf = new Configuration();
+    newConf.setClass("fs.AbstractFileSystem.mockfs.impl", MockFs.class,
+        AbstractFileSystem.class);
+    ConfigUtil.addLink(newConf, mountPoint.toString(), mockTarget.toUri());
+    FileContext.getFileContext(URI.create("viewfs:///"), newConf)
+        .listStatus(mountPoint);
+    AbstractFileSystem mockFs = MockFs.getMockFs(mockTarget.toUri());
+    verify(mockFs).listStatusIterator(new Path(mockTarget.toUri().getPath()));
+    verify(mockFs, never()).listStatus(any(Path.class));
+  }
+
+  static class MockFs extends ChRootedFs {
+    private static Map<String, AbstractFileSystem> fsCache = new HashMap<>();
+    MockFs(URI uri, Configuration conf) throws URISyntaxException {
+      super(getMockFs(uri), new Path("/"));
+    }
+    static AbstractFileSystem getMockFs(URI uri) {
+      AbstractFileSystem mockFs = fsCache.get(uri.getAuthority());
+      if (mockFs == null) {
+        mockFs = mock(AbstractFileSystem.class);
+        when(mockFs.getUri()).thenReturn(uri);
+        when(mockFs.getUriDefaultPort()).thenReturn(1);
+        when(mockFs.getUriPath(any(Path.class))).thenCallRealMethod();
+        when(mockFs.isValidName(anyString())).thenReturn(true);
+        fsCache.put(uri.getAuthority(), mockFs);
+      }
+      return mockFs;
+    }
+  }
 }