From 07ba2fc47f5d9c888ccb11ca3666f215159b5f45 Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Wed, 26 Mar 2014 14:34:56 +0000
Subject: Only write back file attributes if any of them really changed.

---
 unix/tclUnixFCmd.c | 23 +++++++++++------------
 win/tclWinFCmd.c   |  7 ++++---
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/unix/tclUnixFCmd.c b/unix/tclUnixFCmd.c
index 259c7e5..3b1b6ca 100644
--- a/unix/tclUnixFCmd.c
+++ b/unix/tclUnixFCmd.c
@@ -2289,11 +2289,12 @@ StatError(
 }
 
 static WCHAR *
-winPathFromNative(
-    const char *native)
+winPathFromObj(
+    Tcl_Obj *fileName)
 {
-	int size;
-	WCHAR *winPath;
+    int size;
+    const char *native =  Tcl_FSGetNativePath(fileName);
+    WCHAR *winPath;
 
     size = cygwin_conv_path(1, native, NULL, 0);
     winPath = ckalloc(size);
@@ -2330,8 +2331,7 @@ GetUnixFileAttributes(
     Tcl_Obj **attributePtrPtr)	/* A pointer to return the object with. */
 {
     int fileAttributes;
-    const char *native = Tcl_FSGetNativePath(fileName);
-    WCHAR *winPath = winPathFromNative(native);
+    WCHAR *winPath = winPathFromObj(fileName);
 
     fileAttributes = GetFileAttributesW(winPath);
     ckfree(winPath);
@@ -2369,18 +2369,16 @@ SetUnixFileAttributes(
     Tcl_Obj *fileName,      /* The name of the file (UTF-8). */
     Tcl_Obj *attributePtr)  /* The attribute to set. */
 {
-    int yesNo, fileAttributes;
-    const char *native;
+    int yesNo, fileAttributes, old;
     WCHAR *winPath;
 
     if (Tcl_GetBooleanFromObj(interp, attributePtr, &yesNo) != TCL_OK) {
 	return TCL_ERROR;
     }
 
-    native = Tcl_FSGetNativePath(fileName);
-    winPath = winPathFromNative(native);
+    winPath = winPathFromObj(fileName);
 
-    fileAttributes = GetFileAttributesW(winPath);
+    fileAttributes = old = GetFileAttributesW(winPath);
 
     if (fileAttributes == -1) {
 	ckfree(winPath);
@@ -2394,7 +2392,8 @@ SetUnixFileAttributes(
 	fileAttributes &= ~attributeArray[objIndex];
     }
 
-    if (!SetFileAttributesW(winPath, fileAttributes)) {
+    if ((fileAttributes != old)
+	    && !SetFileAttributesW(winPath, fileAttributes)) {
 	ckfree(winPath);
 	StatError(interp, fileName);
 	return TCL_ERROR;
diff --git a/win/tclWinFCmd.c b/win/tclWinFCmd.c
index 2700cb3..f14d9ff 100644
--- a/win/tclWinFCmd.c
+++ b/win/tclWinFCmd.c
@@ -1825,12 +1825,12 @@ SetWinFileAttributes(
     Tcl_Obj *fileName,		/* The name of the file. */
     Tcl_Obj *attributePtr)	/* The new value of the attribute. */
 {
-    DWORD fileAttributes;
+    DWORD fileAttributes, old;
     int yesNo, result;
     const TCHAR *nativeName;
 
     nativeName = Tcl_FSGetNativePath(fileName);
-    fileAttributes = GetFileAttributes(nativeName);
+    fileAttributes = old = GetFileAttributes(nativeName);
 
     if (fileAttributes == 0xffffffff) {
 	StatError(interp, fileName);
@@ -1848,7 +1848,8 @@ SetWinFileAttributes(
 	fileAttributes &= ~(attributeArray[objIndex]);
     }
 
-    if (!SetFileAttributes(nativeName, fileAttributes)) {
+    if ((fileAttributes != old)
+	    && !SetFileAttributes(nativeName, fileAttributes)) {
 	StatError(interp, fileName);
 	return TCL_ERROR;
     }
-- 
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