Libify the index refresh logic

This cleans up and libifies the "git update-index --[really-]refresh"
functionality. This will be eventually required for eventually doing the
"commit" and "status" commands as built-ins.

It really just moves "refresh_index()" from update-index.c to
read-cache.c, but it also has to change the calling convention so that the
function uses a "unsigned int flags" argument instead of various static
flags variables for passing down the information about whether to be quiet
or not, and allow unmerged entries etc.

That actually cleans up update-index.c too, since it turns out that all
those flags were really specific to that one function of the index update,
so they shouldn't have had file-scope visibility even before.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 117 insertions, 0 deletions

diff --git a/read-cache.c b/read-cache.c
index a917ab0cfe..b95edcc14c 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -496,6 +496,123 @@ int add_cache_entry(struct cache_entry *ce, int option)
 	return 0;
 }
 
+/* Three functions to allow overloaded pointer return; see linux/err.h */
+static inline void *ERR_PTR(long error)
+{
+	return (void *) error;
+}
+
+static inline long PTR_ERR(const void *ptr)
+{
+	return (long) ptr;
+}
+
+static inline long IS_ERR(const void *ptr)
+{
+	return (unsigned long)ptr > (unsigned long)-1000L;
+}
+
+/*
+ * "refresh" does not calculate a new sha1 file or bring the
+ * cache up-to-date for mode/content changes. But what it
+ * _does_ do is to "re-match" the stat information of a file
+ * with the cache, so that you can refresh the cache for a
+ * file that hasn't been changed but where the stat entry is
+ * out of date.
+ *
+ * For example, you'd want to do this after doing a "git-read-tree",
+ * to link up the stat cache details with the proper files.
+ */
+static struct cache_entry *refresh_entry(struct cache_entry *ce, int really)
+{
+	struct stat st;
+	struct cache_entry *updated;
+	int changed, size;
+
+	if (lstat(ce->name, &st) < 0)
+		return ERR_PTR(-errno);
+
+	changed = ce_match_stat(ce, &st, really);
+	if (!changed) {
+		if (really && assume_unchanged &&
+		    !(ce->ce_flags & htons(CE_VALID)))
+			; /* mark this one VALID again */
+		else
+			return NULL;
+	}
+
+	if (ce_modified(ce, &st, really))
+		return ERR_PTR(-EINVAL);
+
+	size = ce_size(ce);
+	updated = xmalloc(size);
+	memcpy(updated, ce, size);
+	fill_stat_cache_info(updated, &st);
+
+	/* In this case, if really is not set, we should leave
+	 * CE_VALID bit alone.  Otherwise, paths marked with
+	 * --no-assume-unchanged (i.e. things to be edited) will
+	 * reacquire CE_VALID bit automatically, which is not
+	 * really what we want.
+	 */
+	if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID)))
+		updated->ce_flags &= ~htons(CE_VALID);
+
+	return updated;
+}
+
+int refresh_cache(unsigned int flags)
+{
+	int i;
+	int has_errors = 0;
+	int really = (flags & REFRESH_REALLY) != 0;
+	int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
+	int quiet = (flags & REFRESH_QUIET) != 0;
+	int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
+
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce, *new;
+		ce = active_cache[i];
+		if (ce_stage(ce)) {
+			while ((i < active_nr) &&
+			       ! strcmp(active_cache[i]->name, ce->name))
+				i++;
+			i--;
+			if (allow_unmerged)
+				continue;
+			printf("%s: needs merge\n", ce->name);
+			has_errors = 1;
+			continue;
+		}
+
+		new = refresh_entry(ce, really);
+		if (!new)
+			continue;
+		if (IS_ERR(new)) {
+			if (not_new && PTR_ERR(new) == -ENOENT)
+				continue;
+			if (really && PTR_ERR(new) == -EINVAL) {
+				/* If we are doing --really-refresh that
+				 * means the index is not valid anymore.
+				 */
+				ce->ce_flags &= ~htons(CE_VALID);
+				active_cache_changed = 1;
+			}
+			if (quiet)
+				continue;
+			printf("%s: needs update\n", ce->name);
+			has_errors = 1;
+			continue;
+		}
+		active_cache_changed = 1;
+		/* You can NOT just free active_cache[i] here, since it
+		 * might not be necessarily malloc()ed but can also come
+		 * from mmap(). */
+		active_cache[i] = new;
+	}
+	return has_errors;
+}
+
 static int verify_hdr(struct cache_header *hdr, unsigned long size)
 {
 	SHA_CTX c;