fix Handler.getHostAddress() performance issue

Fixes #85

RELNOTES=n/a

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=278648767

1 files changed, 12 insertions, 0 deletions

diff --git a/jimfs/src/main/java/com/google/common/jimfs/Handler.java b/jimfs/src/main/java/com/google/common/jimfs/Handler.java
index e5bfcbf..fd4ab74 100644
--- a/jimfs/src/main/java/com/google/common/jimfs/Handler.java
+++ b/jimfs/src/main/java/com/google/common/jimfs/Handler.java
@@ -19,6 +19,7 @@ package com.google.common.jimfs;
 import static com.google.common.base.Preconditions.checkArgument;
 
 import java.io.IOException;
+import java.net.InetAddress;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
@@ -77,4 +78,15 @@ public final class Handler extends URLStreamHandler {
   protected URLConnection openConnection(URL url) throws IOException {
     return new PathURLConnection(url);
   }
+
+  @Override
+  @SuppressWarnings("UnsynchronizedOverridesSynchronized") // no need to synchronize to return null
+  protected InetAddress getHostAddress(URL url) {
+    // jimfs uses the URI host to specify the name of the file system being used.
+    // In the default implementation of getHostAddress(URL), a non-null host would cause an attempt
+    // to look up the IP address, causing a slowdown on calling equals/hashCode methods on the URL
+    // object. By returning null, we speed up equality checks on URL's (since there isn't an IP to
+    // connect to).
+    return null;
+  }
 }