lstat_cache(): print a warning if doing ping-pong between cache types

diff --git a/refs.c b/refs.c
index be095cb07d23ca9f0e20d2cc46df33827a123274..024211d72b5e21e1c87e98b0f7e3a6982525d82d 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -390,6 +390,18 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
        return retval;
 }
 
+/*
+ * If the "reading" argument is set, this function finds out what _object_
+ * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
+ * has to exist, and if it is symbolic, it has to point at an existing ref,
+ * because the "read" goes through the symref to the ref it points at.
+ *
+ * The access that is not "reading" may often be "writing", but does not
+ * have to; it can be merely checking _where it leads to_. If it is a
+ * prelude to "writing" to the ref, a write to a symref that points at
+ * yet-to-be-born ref will create the real ref pointed by the symref.
+ * reading=0 allows the caller to check where such a symref leads to.
+ */
 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 {
        int depth = MAXDEPTH;
@@ -410,13 +422,7 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
                        return NULL;
 
                git_snpath(path, sizeof(path), "%s", ref);
-               /* Special case: non-existing file.
-                * Not having the refs/heads/new-branch is OK
-                * if we are writing into it, so is .git/HEAD
-                * that points at refs/heads/master still to be
-                * born.  It is NOT OK if we are resolving for
-                * reading.
-                */
+               /* Special case: non-existing file. */
                if (lstat(path, &st) < 0) {
                        struct ref_list *list = get_packed_refs();
                        while (list) {
@@ -1447,7 +1453,7 @@ int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *
        return 1;
 }
 
-int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
+int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
 {
        const char *logfile;
        FILE *logfp;
@@ -1458,6 +1464,16 @@ int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
        logfp = fopen(logfile, "r");
        if (!logfp)
                return -1;
+
+       if (ofs) {
+               struct stat statbuf;
+               if (fstat(fileno(logfp), &statbuf) ||
+                   statbuf.st_size < ofs ||
+                   fseek(logfp, -ofs, SEEK_END) ||
+                   fgets(buf, sizeof(buf), logfp))
+                       return -1;
+       }
+
        while (fgets(buf, sizeof(buf), logfp)) {
                unsigned char osha1[20], nsha1[20];
                char *email_end, *message;
@@ -1491,6 +1507,11 @@ int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
        return ret;
 }
 
+int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
+{
+       return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
+}
+
 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
 {
        DIR *dir = opendir(git_path("logs/%s", base));