ClientBundle gen should close files when done reading them

ImageBundleBuilder and ImageResourceGenerator don't explicitly close
files when finished with them. On some machines, this results in too
many files being open for the process to open additional files,
preventing compilation from continuing.

Bug: issue 7880
Change-Id: I01aaa65173eb7967a54bc340e7f4885d91c082f7

dev/core/src/com/google/gwt/util/tools/Utility.java

@@ -24,10 +24,7 @@
 import java.io.LineNumberReader;
 import java.io.OutputStream;
 import java.io.PrintWriter;
-import java.io.Reader;
 import java.io.StringReader;
-import java.io.Writer;
-import java.net.Socket;
 import java.net.URI;
 import java.net.URL;
 import java.util.Iterator;
@@ -58,64 +55,12 @@ public final class Utility {
    * Helper that ignores exceptions during close, because what are you going to
    * do?
    */
-  public static void close(InputStream is) {
+  public static void close(AutoCloseable closeable) {
     try {
-      if (is != null) {
-        is.close();
+      if (closeable != null) {
+        closeable.close();
       }
-    } catch (IOException e) {
-    }
-  }
-
-  /**
-   * Helper that ignores exceptions during close, because what are you going to
-   * do?
-   */
-  public static void close(OutputStream os) {
-    try {
-      if (os != null) {
-        os.close();
-      }
-    } catch (IOException e) {
-    }
-  }
-
-  /**
-   * Helper that ignores exceptions during close, because what are you going to
-   * do?
-   */
-  public static void close(Reader reader) {
-    try {
-      if (reader != null) {
-        reader.close();
-      }
-    } catch (IOException e) {
-    }
-  }
-
-  /**
-   * Helper that ignores exceptions during close, because what are you going to
-   * do?
-   */
-  public static void close(Socket socket) {
-    try {
-      if (socket != null) {
-        socket.close();
-      }
-    } catch (IOException e) {
-    }
-  }
-
-  /**
-   * Helper that ignores exceptions during close, because what are you going to
-   * do?
-   */
-  public static void close(Writer writer) {
-    try {
-      if (writer != null) {
-        writer.close();
-      }
-    } catch (IOException e) {
+    } catch (Exception e) {
     }
   }
 

user/src/com/google/gwt/resources/rg/ImageBundleBuilder.java

@@ -31,6 +31,7 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.PrintWriter;
 import java.net.MalformedURLException;
 import java.net.URL;
@@ -693,17 +694,16 @@ private ImageRect addImage(TreeLogger logger, String imageName, URL imageUrl)
     // Be safe by default and assume that the incoming image is lossy
     boolean lossy = true;
     // Load the image
-    try {
+    try (InputStream is = imageUrl.openStream();
+         MemoryCacheImageInputStream imageInputStream = new MemoryCacheImageInputStream(is)) {
       /*
        * ImageIO uses an SPI pattern API. We don't care about the particulars of
        * the implementation, so just choose the first ImageReader.
        */
-      MemoryCacheImageInputStream input = new MemoryCacheImageInputStream(
-          imageUrl.openStream());
-      Iterator<ImageReader> it = ImageIO.getImageReaders(input);
+      Iterator<ImageReader> it = ImageIO.getImageReaders(imageInputStream);
       readers : while (it.hasNext()) {
         ImageReader reader = it.next();
-        reader.setInput(input);
+        reader.setInput(imageInputStream);
 
         int numImages = reader.getNumImages(true);
         if (numImages == 0) {

user/src/com/google/gwt/resources/rg/ImageResourceGenerator.java

@@ -38,11 +38,13 @@
 import com.google.gwt.safehtml.shared.UriUtils;
 import com.google.gwt.user.rebind.SourceWriter;
 import com.google.gwt.user.rebind.StringSourceWriter;
+import com.google.gwt.util.tools.Utility;
 
 import java.awt.geom.AffineTransform;
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
+import java.net.URLConnection;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
@@ -577,12 +579,11 @@ public void prepare(TreeLogger logger, ResourceContext context,
          * they actually offer a space-savings.
          */
         try {
-          URL contentLocation = localizedImage.getUrl();
-          int originalSize = contentLocation.openConnection().getContentLength();
+          int originalSize = getContentLength(localizedImage.getUrl());
 
           // Re-encode the data
           URL reencodedContents = reencodeToTempFile(logger, rect);
-          int newSize = reencodedContents.openConnection().getContentLength();
+          int newSize = getContentLength(reencodedContents);
 
           // But only use it if we did a better job on compression
           if (newSize < originalSize) {
@@ -608,6 +609,19 @@ public void prepare(TreeLogger logger, ResourceContext context,
     }
   }
 
+  /**
+   * Helper method to read the contentLength of a given URL, automatically
+   * closing the InputStream that is opened as a side effect.
+   */
+  private int getContentLength(URL url) throws IOException {
+    URLConnection conn = url.openConnection();
+    try {
+      return conn.getContentLength();
+    } finally {
+      Utility.close(conn.getInputStream());
+    }
+  }
+
   /**
    * Creates a cache key to be used with {@link ResourceContext#putCachedData}.
    * The key is based on the ClientBundle type, support for data URLs, and the