Fix writes with 0 length

gcloud-java-core/src/main/java/com/google/gcloud/BaseServiceException.java

@@ -97,13 +97,17 @@ public BaseServiceException(IOException exception, boolean idempotent) {
     String debugInfo = null;
     if (exception instanceof GoogleJsonResponseException) {
       GoogleJsonError jsonError = ((GoogleJsonResponseException) exception).getDetails();
-      Error error = error(jsonError);
-      code = error.code;
-      reason = error.reason;
-      if (reason != null) {
-        GoogleJsonError.ErrorInfo errorInfo = jsonError.getErrors().get(0);
-        location = errorInfo.getLocation();
-        debugInfo = (String) errorInfo.get("debugInfo");
+      if (jsonError != null) {
+        Error error = error(jsonError);
+        code = error.code;
+        reason = error.reason;
+        if (reason != null) {
+          GoogleJsonError.ErrorInfo errorInfo = jsonError.getErrors().get(0);
+          location = errorInfo.getLocation();
+          debugInfo = (String) errorInfo.get("debugInfo");
+        }
+      } else {
+        code = ((GoogleJsonResponseException) exception).getStatusCode();
       }
     }
     this.code = code;
@@ -207,7 +211,10 @@ protected static Error error(GoogleJsonError error) {
 
   protected static String message(IOException exception) {
     if (exception instanceof GoogleJsonResponseException) {
-      return ((GoogleJsonResponseException) exception).getDetails().getMessage();
+      GoogleJsonError details = ((GoogleJsonResponseException) exception).getDetails();
+      if (details != null) {
+        return details.getMessage();
+      }
     }
     return exception.getMessage();
   }

gcloud-java-storage/src/main/java/com/google/gcloud/spi/DefaultStorageRpc.java

@@ -31,6 +31,7 @@
 import static com.google.gcloud.spi.StorageRpc.Option.PREFIX;
 import static com.google.gcloud.spi.StorageRpc.Option.VERSIONS;
 import static java.net.HttpURLConnection.HTTP_NOT_FOUND;
+import static javax.servlet.http.HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE;
 
 import com.google.api.client.googleapis.batch.json.JsonBatchCallback;
 import com.google.api.client.googleapis.json.GoogleJsonError;
@@ -453,20 +454,32 @@ public Tuple<String, byte[]> read(StorageObject from, Map<Option, ?> options, lo
       String etag = req.getLastResponseHeaders().getETag();
       return Tuple.of(etag, output.toByteArray());
     } catch (IOException ex) {
-      throw translate(ex);
+      StorageException serviceException = translate(ex);
+      if (serviceException.code() == SC_REQUESTED_RANGE_NOT_SATISFIABLE) {
+        return Tuple.of(null, new byte[0]);
+      }
+      throw serviceException;
     }
   }
 
   @Override
   public void write(String uploadId, byte[] toWrite, int toWriteOffset, long destOffset, int length,
       boolean last) {
     try {
+      if (length == 0 && !last) {
+        return;
+      }
       GenericUrl url = new GenericUrl(uploadId);
       HttpRequest httpRequest = storage.getRequestFactory().buildPutRequest(url,
           new ByteArrayContent(null, toWrite, toWriteOffset, length));
       long limit = destOffset + length;
       StringBuilder range = new StringBuilder("bytes ");
-      range.append(destOffset).append('-').append(limit - 1).append('/');
+      if (length == 0) {
+        range.append('*');
+      } else {
+        range.append(destOffset).append('-').append(limit - 1);
+      }
+      range.append('/');
       if (last) {
         range.append(limit);
       } else {

gcloud-java-storage/src/main/java/com/google/gcloud/storage/BlobReadChannel.java

@@ -127,7 +127,7 @@ public Tuple<String, byte[]> call() {
             return storageRpc.read(storageObject, requestOptions, position, toRead);
           }
         }, serviceOptions.retryParams(), StorageImpl.EXCEPTION_HANDLER);
-        if (lastEtag != null && !Objects.equals(result.x(), lastEtag)) {
+        if (result.y().length > 0 && lastEtag != null && !Objects.equals(result.x(), lastEtag)) {
           StringBuilder messageBuilder = new StringBuilder();
           messageBuilder.append("Blob ").append(blob).append(" was updated while reading");
           throw new StorageException(0, messageBuilder.toString());

gcloud-java-storage/src/test/java/com/google/gcloud/storage/it/ITStorageTest.java

@@ -54,6 +54,7 @@
 import org.junit.Test;
 
 import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
@@ -823,6 +824,33 @@ public void testReadAndWriteChannels() throws IOException {
     assertTrue(storage.delete(BUCKET, blobName));
   }
 
+  @Test
+  public void testReadAndWriteChannelsWithDifferentFileSize() throws IOException {
+    String blobNamePrefix = "test-read-and-write-channels-blob-";
+    int[] blobSizes = {0, 700, 1024 * 256, 2 * 1024 * 1024, 4 * 1024 * 1024, 4 * 1024 * 1024 + 1};
+    Random rnd = new Random();
+    for (int blobSize : blobSizes) {
+      String blobName = blobNamePrefix + blobSize;
+      BlobInfo blob = BlobInfo.builder(BUCKET, blobName).build();
+      byte[] bytes = new byte[blobSize];
+      rnd.nextBytes(bytes);
+      try (WriteChannel writer = storage.writer(blob)) {
+        writer.write(ByteBuffer.wrap(bytes));
+      }
+      ByteArrayOutputStream output = new ByteArrayOutputStream();
+      try (ReadChannel reader = storage.reader(blob.blobId())) {
+        ByteBuffer buffer = ByteBuffer.allocate(64 * 1024);
+        while (reader.read(buffer) > 0) {
+          buffer.flip();
+          output.write(buffer.array(), 0, buffer.limit());
+          buffer.clear();
+        }
+      }
+      assertArrayEquals(bytes, output.toByteArray());
+      assertTrue(storage.delete(BUCKET, blobName));
+    }
+  }
+
   @Test
   public void testReadAndWriteCaptureChannels() throws IOException {
     String blobName = "test-read-and-write-capture-channels-blob";