Merge pull request #595 from onemanbucket/jenkins-15418

[FIXED JENKINS-15418] Allow long paths on windows.

core/src/main/java/hudson/util/jna/Kernel32Utils.java

@@ -58,7 +58,22 @@ public class Kernel32Utils {
     }
 
     public static int getWin32FileAttributes(File file) throws IOException {
-      return Kernel32.INSTANCE.GetFileAttributesW(new WString(file.getCanonicalPath()));
+   	// allow lookup of paths longer than MAX_PATH
+    	// http://msdn.microsoft.com/en-us/library/aa365247(v=VS.85).aspx
+    	String canonicalPath = file.getCanonicalPath();
+    	String path = null;
+    	if(canonicalPath.length() < 260) {
+    		// path is short, use as-is
+    		path = canonicalPath;
+    	} else if(canonicalPath.startsWith("\\\\")) {
+    		// network share
+    		// \\server\share --> \\?\UNC\server\share
+    		path = "\\\\?\\UNC\\" + canonicalPath.substring(2);
+    	} else {
+    		// prefix, canonical path should be normalized and absolute so this should work.
+    		path = "\\\\?\\" + canonicalPath;
+    	}
+      return Kernel32.INSTANCE.GetFileAttributesW(new WString(path));
     }
 
     public static boolean isJunctionOrSymlink(File file) throws IOException {

core/src/test/java/hudson/FilePathTest.java

@@ -474,5 +474,32 @@ public class FilePathTest extends ChannelTestCase {
             Util.deleteRecursive(tmp);
         }
     }
-
+   
+    @Bug(15418)
+    public void testDeleteLongPathOnWindows() throws Exception {
+        File tmp = Util.createTempDir();
+        try {
+            FilePath d = new FilePath(french, tmp.getPath());
+            
+            // construct a very long path
+            StringBuilder sb = new StringBuilder();
+            while(sb.length() + tmp.getPath().length() < 260 - "very/".length()) {
+                sb.append("very/");
+            }
+            sb.append("pivot/very/very/long/path");
+            
+            FilePath longPath = d.child(sb.toString()); 
+            longPath.mkdirs();
+            FilePath childInLongPath = longPath.child("file.txt");
+            childInLongPath.touch(0);
+            
+            File firstDirectory = new File(tmp.getAbsolutePath() + "/very");
+            Util.deleteRecursive(firstDirectory);
+            
+            assertFalse("Could not delete directory!", firstDirectory.exists());
+            
+        } finally {
+            Util.deleteRecursive(tmp);
+        }
+    }
 }