changeset 51335:80fe6f64d8a0

8199124: (fs) Reduce allocation for file system methods that are invoked with no open options Reviewed-by: alanb Contributed-by: Michael Skells <mike.skells1@gmail.com>
author bpb
date Thu, 21 Jun 2018 11:10:55 -0700
parents 97e9c4f58986
children 2c9e2ec54a11
files src/java.base/share/classes/java/nio/channels/AsynchronousFileChannel.java src/java.base/share/classes/java/nio/channels/FileChannel.java src/java.base/share/classes/java/nio/file/Files.java src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java
diffstat 4 files changed, 36 insertions(+), 16 deletions(-) [+]
line wrap: on
line diff
--- a/src/java.base/share/classes/java/nio/channels/AsynchronousFileChannel.java	Thu Jun 21 18:56:35 2018 +0100
+++ b/src/java.base/share/classes/java/nio/channels/AsynchronousFileChannel.java	Thu Jun 21 11:10:55 2018 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -301,8 +301,13 @@
     public static AsynchronousFileChannel open(Path file, OpenOption... options)
         throws IOException
     {
-        Set<OpenOption> set = new HashSet<>(options.length);
-        Collections.addAll(set, options);
+        Set<OpenOption> set;
+        if (options.length == 0) {
+            set = Collections.emptySet();
+        } else {
+            set = new HashSet<>();
+            Collections.addAll(set, options);
+        }
         return open(file, set, null, NO_ATTRIBUTES);
     }
 
--- a/src/java.base/share/classes/java/nio/channels/FileChannel.java	Thu Jun 21 18:56:35 2018 +0100
+++ b/src/java.base/share/classes/java/nio/channels/FileChannel.java	Thu Jun 21 11:10:55 2018 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -335,8 +335,13 @@
     public static FileChannel open(Path path, OpenOption... options)
         throws IOException
     {
-        Set<OpenOption> set = new HashSet<>(options.length);
-        Collections.addAll(set, options);
+        Set<OpenOption> set;
+        if (options.length == 0) {
+            set = Collections.emptySet();
+        } else {
+            set = new HashSet<>();
+            Collections.addAll(set, options);
+        }
         return open(path, set, NO_ATTRIBUTES);
     }
 
--- a/src/java.base/share/classes/java/nio/file/Files.java	Thu Jun 21 18:56:35 2018 +0100
+++ b/src/java.base/share/classes/java/nio/file/Files.java	Thu Jun 21 11:10:55 2018 -0700
@@ -410,8 +410,13 @@
     public static SeekableByteChannel newByteChannel(Path path, OpenOption... options)
         throws IOException
     {
-        Set<OpenOption> set = new HashSet<>(options.length);
-        Collections.addAll(set, options);
+        Set<OpenOption> set;
+        if (options.length == 0) {
+            set = Collections.emptySet();
+        } else {
+            set = new HashSet<>();
+            Collections.addAll(set, options);
+        }
         return newByteChannel(path, set);
     }
 
@@ -599,6 +604,9 @@
 
     // -- Creation and deletion --
 
+    private static final Set<OpenOption> DEFAULT_CREATE_OPTIONS =
+        Set.of(StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
+
     /**
      * Creates a new and empty file, failing if the file already exists. The
      * check for the existence of the file and the creation of the new file if
@@ -635,9 +643,7 @@
     public static Path createFile(Path path, FileAttribute<?>... attrs)
         throws IOException
     {
-        EnumSet<StandardOpenOption> options =
-            EnumSet.<StandardOpenOption>of(StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
-        newByteChannel(path, options, attrs).close();
+        newByteChannel(path, DEFAULT_CREATE_OPTIONS, attrs).close();
         return path;
     }
 
--- a/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java	Thu Jun 21 18:56:35 2018 +0100
+++ b/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java	Thu Jun 21 11:10:55 2018 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -384,6 +384,10 @@
         return Channels.newInputStream(Files.newByteChannel(path, options));
     }
 
+    private static final Set<OpenOption> DEFAULT_OPEN_OPTIONS =
+        Set.of(StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING,
+            StandardOpenOption.WRITE);
+
     /**
      * Opens or creates a file, returning an output stream that may be used to
      * write bytes to the file. This method works in exactly the manner
@@ -419,18 +423,18 @@
         throws IOException
     {
         int len = options.length;
-        Set<OpenOption> opts = new HashSet<>(len + 3);
+        Set<OpenOption> opts ;
         if (len == 0) {
-            opts.add(StandardOpenOption.CREATE);
-            opts.add(StandardOpenOption.TRUNCATE_EXISTING);
+            opts = DEFAULT_OPEN_OPTIONS;
         } else {
+            opts = new HashSet<>();
             for (OpenOption opt: options) {
                 if (opt == StandardOpenOption.READ)
                     throw new IllegalArgumentException("READ not allowed");
                 opts.add(opt);
             }
+            opts.add(StandardOpenOption.WRITE);
         }
-        opts.add(StandardOpenOption.WRITE);
         return Channels.newOutputStream(newByteChannel(path, opts));
     }