From 3b6e48e7a9c663a8cee7fdff127cbfe9e47daf6a Mon Sep 17 00:00:00 2001
From: Michael Bayne <mdb@threerings.net>
Date: Fri, 13 Apr 2007 20:50:12 +0000
Subject: [PATCH] Reinstate the "move the old file out of the way then move the
 new file in place" Windows-friendly rename and try that before falling back
 to the brute force copy (which risks failing due to a full disk and leaving
 us with a corrupt file rather than just an out of date one).

---
 .../com/threerings/getdown/util/FileUtil.java | 27 +++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/java/com/threerings/getdown/util/FileUtil.java b/src/java/com/threerings/getdown/util/FileUtil.java
index 94e3220..56d46bb 100644
--- a/src/java/com/threerings/getdown/util/FileUtil.java
+++ b/src/java/com/threerings/getdown/util/FileUtil.java
@@ -49,14 +49,37 @@ public class FileUtil
             return true;
         }
 
-        // otherwise try copying the old data over the new
+        // fall back to trying to rename the old file out of the way, rename the new file into
+        // place and then delete the old file
+        if (dest.exists()) {
+            File temp = new File(dest.getPath() + "_old");
+            if (temp.exists()) {
+                if (!temp.delete()) {
+                    Log.warning("Failed to delete old intermediate file " + temp + ".");
+                    // the subsequent code will probably fail
+                }
+            }
+            if (dest.renameTo(temp)) {
+                if (source.renameTo(dest)) {
+                    if (temp.delete()) {
+                        Log.warning("Failed to delete intermediate file " + temp + ".");
+                    }
+                    return true;
+                }
+            }
+        }
+
+        // as a last resort, try copying the old data over the new
         FileInputStream fin = null;
         FileOutputStream fout = null;
         try {
             fin = new FileInputStream(source);
             fout = new FileOutputStream(dest);
             IOUtils.copy(fin, fout);
-            source.delete();
+            if (!source.delete()) {
+                Log.warning("Failed to delete " + source +
+                            " after brute force copy to " + dest + ".");
+            }
             return true;
 
         } catch (IOException ioe) {