Workaround Win32 problems with rename(2) applied to open/mapped
files (it fails with EPERM). Thanks to Christopher Faylor for the
hint regarding open files. The more complete patch.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>

diff --git a/apply.c b/apply.c
--- a/apply.c
+++ b/apply.c
@@ -1453,9 +1453,12 @@ static int apply_patch(int fd)
 		write_out_results(list, skipped_patch);
 
 	if (write_index) {
-		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
+		if (write_cache(newfd, active_cache, active_nr))
 			die("Unable to write new cachefile");
+		close(newfd);
+		unmap_active_cache();
+		if (commit_index_file(&cache_file))
+			die("Unable to commit new cachefile");
 	}
 
 	if (show_files)
diff --git a/cache.h b/cache.h
--- a/cache.h
+++ b/cache.h
@@ -166,6 +166,7 @@ extern int ce_modified(struct cache_entr
 extern int ce_path_match(const struct cache_entry *ce, const char **pathspec);
 extern int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type);
 extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
+extern void unmap_active_cache();
 
 struct cache_file {
 	struct cache_file *next;
diff --git a/checkout-index.c b/checkout-index.c
--- a/checkout-index.c
+++ b/checkout-index.c
@@ -143,9 +143,13 @@ int main(int argc, char **argv)
 		checkout_file(arg);
 	}
 
-	if (0 <= newfd &&
-	    (write_cache(newfd, active_cache, active_nr) ||
-	     commit_index_file(&cache_file)))
-		die("Unable to write new cachefile");
+	if (0 <= newfd) {
+		if (write_cache(newfd, active_cache, active_nr))
+			die("Unable to write new cachefile");
+		close(newfd);
+		unmap_active_cache();
+		if (commit_index_file(&cache_file))
+			die("Unable to commit new cachefile");
+        }
 	return 0;
 }
diff --git a/read-cache.c b/read-cache.c
--- a/read-cache.c
+++ b/read-cache.c
@@ -454,6 +454,17 @@ static int verify_hdr(struct cache_heade
 	return 0;
 }
 
+static void* active_cache_map = MAP_FAILED;
+static size_t active_cache_map_size = 0;
+
+void unmap_active_cache()
+{
+	if ( active_cache_map != MAP_FAILED ) {
+		active_nr = 0;
+		munmap(active_cache_map, active_cache_map_size);
+	}
+}
+
 int read_cache(void)
 {
 	int fd, i;
@@ -490,6 +501,8 @@ int read_cache(void)
 	if (verify_hdr(hdr, size) < 0)
 		goto unmap;
 
+	active_cache_map = map;
+	active_cache_map_size = size;
 	active_nr = ntohl(hdr->hdr_entries);
 	active_alloc = alloc_nr(active_nr);
 	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
diff --git a/read-tree.c b/read-tree.c
--- a/read-tree.c
+++ b/read-tree.c
@@ -690,8 +690,11 @@ int main(int argc, char **argv)
 	}
 
 	unpack_trees(fn);
-	if (write_cache(newfd, active_cache, active_nr) ||
-	    commit_index_file(&cache_file))
+	if (write_cache(newfd, active_cache, active_nr))
 		die("unable to write new index file");
+	close(newfd);
+	unmap_active_cache();
+	if (commit_index_file(&cache_file))
+		die("unable to commit new index file");
 	return 0;
 }
diff --git a/update-index.c b/update-index.c
--- a/update-index.c
+++ b/update-index.c
@@ -392,9 +392,13 @@ int main(int argc, const char **argv)
 		}
 	}
 	if (active_cache_changed) {
-		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
+		if (write_cache(newfd, active_cache, active_nr))
 			die("Unable to write new cachefile");
+		/* close and unmap are just to workaround win32 stupidity */
+		close(newfd);
+		unmap_active_cache();
+		if (commit_index_file(&cache_file))
+			die("Unable to commit new cachefile");
 	}
 
 	return has_errors ? 1 : 0;