JCLOUDS-1371: JCLOUDS-1488: list optimize prefix

Previously getBlobKeysInsideContainer returned all keys and filtered
in LocalBlobStore.  Now getBlobKeysInsideContainer filters via prefix
which can dramatically decrease the number of keys returned,
especially for the filesystem provider.  Further optimizations are
possible for delimiter.

apis/filesystem/src/main/java/org/jclouds/filesystem/strategy/internal/FilesystemStorageStrategyImpl.java

@@ -342,7 +342,7 @@ public class FilesystemStorageStrategyImpl implements LocalStorageStrategy {
     * @throws IOException
     */
    @Override
-   public Iterable<String> getBlobKeysInsideContainer(String container) throws IOException {
+   public Iterable<String> getBlobKeysInsideContainer(String container, String prefix) throws IOException {
       filesystemContainerNameValidator.validate(container);
       // check if container exists
       // TODO maybe an error is more appropriate
@@ -353,7 +353,7 @@ public class FilesystemStorageStrategyImpl implements LocalStorageStrategy {
 
       File containerFile = openFolder(container);
       final int containerPathLength = containerFile.getAbsolutePath().length() + 1;
-      populateBlobKeysInContainer(containerFile, blobNames, new Function<String, String>() {
+      populateBlobKeysInContainer(containerFile, blobNames, prefix, new Function<String, String>() {
          @Override
          public String apply(String string) {
             return denormalize(string.substring(containerPathLength));
@@ -753,7 +753,7 @@ public class FilesystemStorageStrategyImpl implements LocalStorageStrategy {
    public long countBlobs(String container, ListContainerOptions options) {
       // TODO: honor options
       try {
-         return Iterables.size(getBlobKeysInsideContainer(container));
+         return Iterables.size(getBlobKeysInsideContainer(container, null));
       } catch (IOException ioe) {
          throw Throwables.propagate(ioe);
       }
@@ -964,17 +964,27 @@ public class FilesystemStorageStrategyImpl implements LocalStorageStrategy {
    }
 
    private static void populateBlobKeysInContainer(File directory, Set<String> blobNames,
-         Function<String, String> function) {
+         String prefix, Function<String, String> function) {
       File[] children = directory.listFiles();
       if (children == null) {
          return;
       }
       for (File child : children) {
+         String fullPath = function.apply(child.getAbsolutePath());
          if (child.isFile()) {
-            blobNames.add( function.apply(child.getAbsolutePath()) );
+            if (prefix != null && !fullPath.startsWith(prefix)) {
+               continue;
+            }
+            blobNames.add(fullPath);
          } else if (child.isDirectory()) {
-            blobNames.add(function.apply(child.getAbsolutePath()) + File.separator); // TODO: undo if failures
+            // Consider a prefix /a/b/c but we have only descended to path /a.
-            populateBlobKeysInContainer(child, blobNames, function);
+            // We need to match the path against the prefix to continue
+            // matching down to /a/b.
+            if (prefix != null && !fullPath.startsWith(prefix) && !prefix.startsWith(fullPath + "/")) {
+               continue;
+            }
+            blobNames.add(fullPath + File.separator); // TODO: undo if failures
+            populateBlobKeysInContainer(child, blobNames, prefix, function);
          }
       }
    }

apis/filesystem/src/test/java/org/jclouds/filesystem/strategy/internal/FilesystemStorageStrategyImplTest.java

@@ -427,7 +427,7 @@ public class FilesystemStorageStrategyImplTest {
       Blob blob = storageStrategy.newBlob(blobKey);
       storageStrategy.putBlob(CONTAINER_NAME, blob);
 
-      Iterable<String> keys = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME);
+      Iterable<String> keys = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME, null);
       Iterator<String> iter = keys.iterator();
       assertTrue(iter.hasNext());
       assertEquals(iter.next(), blobKey);
@@ -598,7 +598,7 @@ public class FilesystemStorageStrategyImplTest {
       Iterable<String> resultList;
 
       // no container
-      resultList = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME);
+      resultList = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME, null);
       assertNotNull(resultList, "Result is null");
       assertFalse(resultList.iterator().hasNext(), "Blobs detected");
 
@@ -609,10 +609,10 @@ public class FilesystemStorageStrategyImplTest {
                TestUtils.createRandomBlobKey("GetBlobKeys-", ".jpg"),
                TestUtils.createRandomBlobKey("563" + "/" + "g3sx2" + "/" + "removeBlob-", ".jpg"),
                TestUtils.createRandomBlobKey("563" + "/" + "g3sx2" + "/" + "removeBlob-", ".jpg") });
-      storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME);
+      storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME, null);
 
       List<String> retrievedBlobKeys = Lists.newArrayList();
-      resultList = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME);
+      resultList = storageStrategy.getBlobKeysInsideContainer(CONTAINER_NAME, null);
       Iterator<String> containersIterator = resultList.iterator();
       while (containersIterator.hasNext()) {
          retrievedBlobKeys.add(containersIterator.next());

blobstore/src/main/java/org/jclouds/blobstore/LocalStorageStrategy.java

@@ -98,7 +98,7 @@ public interface LocalStorageStrategy {
      * @return
      * @throws IOException
      */
-    Iterable<String> getBlobKeysInsideContainer(String container) throws IOException;
+    Iterable<String> getBlobKeysInsideContainer(String container, String prefix) throws IOException;
 
     /**
      * Load the blob with the given key belonging to the container with the given

blobstore/src/main/java/org/jclouds/blobstore/TransientStorageStrategy.java

@@ -25,6 +25,7 @@ import java.util.Date;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ConcurrentSkipListMap;
 
 import javax.inject.Inject;
 
@@ -59,7 +60,7 @@ import com.google.common.io.ByteStreams;
 import com.google.common.net.HttpHeaders;
 
 public class TransientStorageStrategy implements LocalStorageStrategy {
-   private final ConcurrentMap<String, ConcurrentMap<String, Blob>> containerToBlobs = new ConcurrentHashMap<String, ConcurrentMap<String, Blob>>();
+   private final ConcurrentMap<String, ConcurrentSkipListMap<String, Blob>> containerToBlobs = new ConcurrentHashMap<String, ConcurrentSkipListMap<String, Blob>>();
    private final ConcurrentMap<String, ConcurrentMap<String, BlobAccess>> containerToBlobAccess = new ConcurrentHashMap<String, ConcurrentMap<String, BlobAccess>>();
    private final ConcurrentMap<String, StorageMetadata> containerMetadata = new ConcurrentHashMap<String, StorageMetadata>();
    private final ConcurrentMap<String, ContainerAccess> containerAccessMap = new ConcurrentHashMap<String, ContainerAccess>();
@@ -90,7 +91,7 @@ public class TransientStorageStrategy implements LocalStorageStrategy {
    @Override
    public boolean createContainerInLocation(String containerName, Location location, CreateContainerOptions options) {
       ConcurrentMap<String, Blob> origValue = containerToBlobs.putIfAbsent(
-            containerName, new ConcurrentHashMap<String, Blob>());
+            containerName, new ConcurrentSkipListMap<String, Blob>());
       if (origValue != null) {
          return false;
       }
@@ -148,8 +149,13 @@ public class TransientStorageStrategy implements LocalStorageStrategy {
    }
 
    @Override
-   public Iterable<String> getBlobKeysInsideContainer(final String containerName) {
+   public Iterable<String> getBlobKeysInsideContainer(final String containerName, String prefix) {
-      return containerToBlobs.get(containerName).keySet();
+      ConcurrentSkipListMap<String, Blob> blobs = containerToBlobs.get(containerName);
+      if (prefix == null) {
+         return blobs.keySet();
+      }
+      String lastPrefix = prefix + (char) 65535;  // TODO: better sentinel?
+      return blobs.subMap(prefix, /*fromInclusive=*/ true, lastPrefix, /*toInclusive=*/ false).keySet();
    }
 
    @Override

blobstore/src/main/java/org/jclouds/blobstore/config/LocalBlobStore.java

@@ -238,7 +238,7 @@ public final class LocalBlobStore implements BlobStore {
       // Loading blobs from container
       Iterable<String> blobBelongingToContainer = null;
       try {
-         blobBelongingToContainer = storageStrategy.getBlobKeysInsideContainer(containerName);
+         blobBelongingToContainer = storageStrategy.getBlobKeysInsideContainer(containerName, options.getPrefix());
       } catch (IOException e) {
          logger.error(e, "An error occurred loading blobs contained into container %s", containerName);
          propagate(e);
@@ -414,7 +414,7 @@ public final class LocalBlobStore implements BlobStore {
       boolean returnVal = true;
       if (storageStrategy.containerExists(containerName)) {
          try {
-            if (Iterables.isEmpty(storageStrategy.getBlobKeysInsideContainer(containerName)))
+            if (Iterables.isEmpty(storageStrategy.getBlobKeysInsideContainer(containerName, null)))
                storageStrategy.deleteContainer(containerName);
             else
                returnVal = false;