8049244: XML Signature performance issue caused by unbuffered signature data

Reviewed-by: xuelei

src/share/classes/org/jcp/xml/dsig/internal/dom/DOMSignedInfo.java

@@ -221,24 +221,24 @@ public final class DOMSignedInfo extends DOMStructure implements SignedInfo {
         }
 
         OutputStream os = new UnsyncBufferedOutputStream(bos);
-        try {
-            os.close();
-        } catch (IOException e) {
-            if (log.isLoggable(java.util.logging.Level.FINE)) {
-                log.log(java.util.logging.Level.FINE, e.getMessage(), e);
-            }
-            // Impossible
-        }
 
         DOMSubTreeData subTree = new DOMSubTreeData(localSiElem, true);
-
         try {
             ((DOMCanonicalizationMethod)
-                canonicalizationMethod).canonicalize(subTree, context, bos);
+                canonicalizationMethod).canonicalize(subTree, context, os);
         } catch (TransformException te) {
             throw new XMLSignatureException(te);
         }
 
+        try {
+            os.flush();
+        } catch (IOException e) {
+            if (log.isLoggable(java.util.logging.Level.FINE)) {
+                log.log(java.util.logging.Level.FINE, e.getMessage(), e);
+            }
+            // Impossible
+        }
+
         byte[] signedInfoBytes = bos.toByteArray();
 
         // this whole block should only be done if logging is enabled
@@ -253,6 +253,15 @@ public final class DOMSignedInfo extends DOMStructure implements SignedInfo {
         }
 
         this.canonData = new ByteArrayInputStream(signedInfoBytes);
+
+        try {
+            os.close();
+        } catch (IOException e) {
+            if (log.isLoggable(java.util.logging.Level.FINE)) {
+                log.log(java.util.logging.Level.FINE, e.getMessage(), e);
+            }
+            // Impossible
+        }
     }
 
     public void marshal(Node parent, String dsPrefix, DOMCryptoContext context)