Fix loading both model and serializer at once from stream + re-add checks

Signed-off-by: Alex Black <blacka101@gmail.com>

deeplearning4j/deeplearning4j-nn/src/main/java/org/deeplearning4j/util/ModelSerializer.java

@@ -16,6 +16,7 @@
 
 package org.deeplearning4j.util;
 
+import org.apache.commons.io.input.CloseShieldInputStream;
 import org.nd4j.shade.guava.io.Files;
 import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
@@ -235,6 +236,11 @@ public class ModelSerializer {
      */
     public static MultiLayerNetwork restoreMultiLayerNetwork(@NonNull InputStream is, boolean loadUpdater)
             throws IOException {
+        return restoreMultiLayerNetworkHelper(is, loadUpdater).getFirst();
+    }
+
+    private static Pair<MultiLayerNetwork, Map<String,byte[]>> restoreMultiLayerNetworkHelper(@NonNull InputStream is, boolean loadUpdater)
+            throws IOException {
         checkInputStream(is);
 
         Map<String, byte[]> zipFile = loadZipData(is);
@@ -343,7 +349,7 @@ public class ModelSerializer {
             if (gotUpdaterState && updaterState != null) {
                 network.getUpdater().setStateViewArray(network, updaterState, false);
             }
-            return network;
+            return new Pair<>(network, zipFile);
         } else
             throw new IllegalStateException("Model wasnt found within file: gotConfig: [" + gotConfig
                     + "], gotCoefficients: [" + gotCoefficients + "], gotUpdater: [" + gotUpdaterState + "]");
@@ -399,9 +405,11 @@ public class ModelSerializer {
     public static Pair<MultiLayerNetwork, Normalizer> restoreMultiLayerNetworkAndNormalizer(
             @NonNull InputStream is, boolean loadUpdater) throws IOException {
         checkInputStream(is);
+        is = new CloseShieldInputStream(is);
 
-        MultiLayerNetwork net = restoreMultiLayerNetwork(is, loadUpdater);
+        Pair<MultiLayerNetwork,Map<String,byte[]>> p = restoreMultiLayerNetworkHelper(is, loadUpdater);
-        Normalizer norm = restoreNormalizerFromInputStream(is);
+        MultiLayerNetwork net = p.getFirst();
+        Normalizer norm = restoreNormalizerFromMap(p.getSecond());
         return new Pair<>(net, norm);
     }
 
@@ -453,6 +461,11 @@ public class ModelSerializer {
      */
     public static ComputationGraph restoreComputationGraph(@NonNull InputStream is, boolean loadUpdater)
             throws IOException {
+        return restoreComputationGraphHelper(is, loadUpdater).getFirst();
+    }
+
+    private static Pair<ComputationGraph,Map<String,byte[]>> restoreComputationGraphHelper(@NonNull InputStream is, boolean loadUpdater)
+            throws IOException {
         checkInputStream(is);
 
         Map<String, byte[]> files = loadZipData(is);
@@ -564,7 +577,7 @@ public class ModelSerializer {
             if (gotUpdaterState && updaterState != null) {
                 cg.getUpdater().setStateViewArray(updaterState);
             }
-            return cg;
+            return new Pair<>(cg, files);
         } else
             throw new IllegalStateException("Model wasnt found within file: gotConfig: [" + gotConfig
                     + "], gotCoefficients: [" + gotCoefficients + "], gotUpdater: [" + gotUpdaterState + "]");
@@ -605,8 +618,10 @@ public class ModelSerializer {
             @NonNull InputStream is, boolean loadUpdater) throws IOException {
         checkInputStream(is);
 
-        ComputationGraph net = restoreComputationGraph(is, loadUpdater);
+
-        Normalizer norm = restoreNormalizerFromInputStream(is);
+        Pair<ComputationGraph,Map<String,byte[]>> p = restoreComputationGraphHelper(is, loadUpdater);
+        ComputationGraph net = p.getFirst();
+        Normalizer norm = restoreNormalizerFromMap(p.getSecond());
         return new Pair<>(net, norm);
     }
 
@@ -900,8 +915,11 @@ public class ModelSerializer {
      */
     public static <T extends Normalizer> T restoreNormalizerFromInputStream(InputStream is) throws IOException {
         checkInputStream(is);
-
         Map<String, byte[]> files = loadZipData(is);
+        return restoreNormalizerFromMap(files);
+    }
+
+    private static <T extends Normalizer> T restoreNormalizerFromMap(Map<String, byte[]> files) throws IOException {
         byte[] norm = files.get(NORMALIZER_BIN);
 
         // checking for file existence
@@ -937,8 +955,6 @@ public class ModelSerializer {
 
 
     private static void checkInputStream(InputStream inputStream) throws IOException {
-
-        /*
         //available method can return 0 in some cases: https://github.com/deeplearning4j/deeplearning4j/issues/4887
         int available;
         try{
@@ -953,7 +969,6 @@ public class ModelSerializer {
             throw new IOException("Cannot read from stream: stream may have been closed or is attempting to be read from" +
                     "multiple times?");
         }
-        */
     }
 
     private static Map<String, byte[]> loadZipData(InputStream is) throws IOException {