Make "update-cache" a bit friendlier to use (and harder to mis-use).

It now requires the "--add" flag before you add any new files, and
a "--remove" file if you want to mark files for removal. And giving
it the "--refresh" flag makes it just update all the files that it
already knows about.

cache.h

@@ -75,7 +75,7 @@ unsigned int active_nr, active_alloc;
 extern int read_cache(void);
 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 extern int cache_name_pos(const char *name, int namelen);
-extern int add_cache_entry(struct cache_entry *ce);
+extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
 extern int remove_file_from_cache(char *path);
 extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 
@@ -104,7 +104,7 @@ extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 
 /* General helper functions */
-extern void usage(const char *err);
+extern void usage(const char *err, ...);
 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 
 #endif /* CACHE_H */

read-cache.c

@@ -9,9 +9,13 @@ const char *sha1_file_directory = NULL;
 struct cache_entry **active_cache = NULL;
 unsigned int active_nr = 0, active_alloc = 0;
 
-void usage(const char *err)
+void usage(const char *err, ...)
 {
-	fprintf(stderr, "read-tree: %s\n", err);
+	va_list args;
+
+	va_start(args, err);
+	vfprintf(stderr, err, args);
+	va_end(args);
 	exit(1);
 }
 
@@ -294,7 +298,7 @@ int remove_file_from_cache(char *path)
 	return 0;
 }
 
-int add_cache_entry(struct cache_entry *ce)
+int add_cache_entry(struct cache_entry *ce, int ok_to_add)
 {
 	int pos;
 
@@ -306,6 +310,9 @@ int add_cache_entry(struct cache_entry *ce)
 		return 0;
 	}
 
+	if (!ok_to_add)
+		return -1;
+
 	/* Make sure the array is big enough .. */
 	if (active_nr == active_alloc) {
 		active_alloc = alloc_nr(active_alloc);

read-tree.c

@@ -18,7 +18,7 @@ static int read_one_entry(unsigned char *sha1, const char *base, int baselen, co
 	memcpy(ce->name, base, baselen);
 	memcpy(ce->name + baselen, pathname, len+1);
 	memcpy(ce->sha1, sha1, 20);
-	return add_cache_entry(ce);
+	return add_cache_entry(ce, 1);
 }
 
 static int read_tree(unsigned char *sha1, const char *base, int baselen)

update-cache.c

@@ -5,6 +5,15 @@
  */
 #include "cache.h"
 
+/*
+ * Default to not allowing changes to the list of files. The
+ * tool doesn't actually care, but this makes it harder to add
+ * files to the revision control by mistake by doing something
+ * like "update-cache *" and suddenly having all the object
+ * files be revision controlled.
+ */
+static int allow_add = 0, allow_remove = 0;
+
 static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
 {
 	z_stream stream;
@@ -57,8 +66,10 @@ static int add_file_to_cache(char *path)
 
 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
-		if (errno == ENOENT)
+		if (errno == ENOENT) {
-			return remove_file_from_cache(path);
+			if (allow_remove)
+				return remove_file_from_cache(path);
+		}
 		return -1;
 	}
 	if (fstat(fd, &st) < 0) {
@@ -85,7 +96,29 @@ static int add_file_to_cache(char *path)
 	if (index_fd(path, namelen, ce, fd, &st) < 0)
 		return -1;
 
-	return add_cache_entry(ce);
+	return add_cache_entry(ce, allow_add);
+}
+
+static void refresh_entry(struct cache_entry *ce)
+{
+	/*
+	 * This is really not the right way to do it, but
+	 * add_file_to_cache() does do the right thing.
+	 *
+	 * We should really just update the cache
+	 * entry in-place, I think. With this approach we
+	 * end up allocating a new one, searching for where
+	 * to insert it etc etc crud.
+	 */
+	add_file_to_cache(ce->name);
+}
+
+static void refresh_cache(void)
+{
+	int i;
+
+	for (i = 0; i < active_nr; i++)
+		refresh_entry(active_cache[i]);
 }
 
 /*
@@ -119,6 +152,7 @@ inside:
 int main(int argc, char **argv)
 {
 	int i, newfd, entries;
+	int allow_options = 1;
 
 	entries = read_cache();
 	if (entries < 0) {
@@ -133,6 +167,26 @@ int main(int argc, char **argv)
 	}
 	for (i = 1 ; i < argc; i++) {
 		char *path = argv[i];
+
+		if (allow_options && *path == '-') {
+			if (!strcmp(path, "--")) {
+				allow_options = 0;
+				continue;
+			}
+			if (!strcmp(path, "--add")) {
+				allow_add = 1;
+				continue;
+			}
+			if (!strcmp(path, "--remove")) {
+				allow_remove = 1;
+				continue;
+			}
+			if (!strcmp(path, "--refresh")) {
+				refresh_cache();
+				continue;
+			}
+			usage("unknown option %s", path);
+		}
 		if (!verify_path(path)) {
 			fprintf(stderr, "Ignoring path %s\n", argv[i]);
 			continue;

write-tree.c

@@ -63,8 +63,6 @@ static int write_tree(struct cache_entry **cachep, int maxentries, const char *b
 			int subdir_written;
 
 			subdir_written = write_tree(cachep + nr, maxentries - nr, pathname, dirname-pathname+1, subdir_sha1);
-			fprintf(stderr, "Wrote %d entries from subdirectory '%.*s'\n", 
-				subdir_written, dirname-pathname, pathname);
 			nr += subdir_written;
 
 			/* Now we need to write out the directory entry into this tree.. */