From: David Turner <dturner@xxxxxxxxxxxxxxxx>
Refactor resolve_ref_1 in terms of a new function read_raw_ref, which
is responsible for reading ref data from the ref storage.
Later, we will make read_raw_ref a pluggable backend function, and make
resolve_ref_unsafe common.
Signed-off-by: David Turner <dturner@xxxxxxxxxxxxxxxx>
Helped-by: Duy Nguyen <pclouds@xxxxxxxxx>
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
Signed-off-by: Michael Haggerty <mhagger@xxxxxxxxxxxx>
---
refs/files-backend.c | 244 ++++++++++++++++++++++++++++++---------------------
1 file changed, 145 insertions(+), 99 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index b865ba5..d51e778 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1390,6 +1390,141 @@ static int resolve_missing_loose_ref(const char *refname,
return -1;
}
+/*
+ * Read a raw ref from the filesystem or packed refs file.
+ *
+ * If the ref is a sha1, fill in sha1 and return 0.
+ *
+ * If the ref is symbolic, fill in *symref with the referrent
+ * (e.g. "refs/heads/master") and return 0. The caller is responsible
+ * for validating the referrent. Set REF_ISSYMREF in flags.
+ *
+ * If the ref doesn't exist, set errno to ENOENT and return -1.
+ *
+ * If the ref exists but is neither a symbolic ref nor a sha1, it is
+ * broken. Set REF_ISBROKEN in flags, set errno to EINVAL, and return
+ * -1.
+ *
+ * If there is another error reading the ref, set errno appropriately and
+ * return -1.
+ *
+ * Backend-specific flags might be set in flags as well, regardless of
+ * outcome.
+ *
+ * sb_path is workspace: the caller should allocate and free it.
+ *
+ * It is OK for refname to point into symref. In this case:
+ * - if the function succeeds with REF_ISSYMREF, symref will be
+ * overwritten and the memory pointed to by refname might be changed
+ * or even freed.
+ * - in all other cases, symref will be untouched, and therefore
+ * refname will still be valid and unchanged.
+ */
+static int read_raw_ref(const char *refname, unsigned char *sha1,
+ struct strbuf *symref, struct strbuf *sb_path,
+ struct strbuf *sb_contents, int *flags)
+{
+ const char *path;
+ const char *buf;
+ struct stat st;
+ int fd;
+
+ strbuf_reset(sb_path);
+ strbuf_git_path(sb_path, "%s", refname);
+ path = sb_path->buf;
+
+stat_ref:
+ /*
+ * We might have to loop back here to avoid a race
+ * condition: first we lstat() the file, then we try
+ * to read it as a link or as a file. But if somebody
+ * changes the type of the file (file <-> directory
+ * <-> symlink) between the lstat() and reading, then
+ * we don't want to report that as an error but rather
+ * try again starting with the lstat().
+ */
+
+ if (lstat(path, &st) < 0) {
+ if (errno != ENOENT)
+ return -1;
+ if (resolve_missing_loose_ref(refname, sha1, flags)) {
+ errno = ENOENT;
+ return -1;
+ }
+ return 0;
+ }
+
+ /* Follow "normalized" - ie "refs/.." symlinks by hand */
+ if (S_ISLNK(st.st_mode)) {
+ strbuf_reset(sb_contents);
+ if (strbuf_readlink(sb_contents, path, 0) < 0) {
+ if (errno == ENOENT || errno == EINVAL)
+ /* inconsistent with lstat; retry */
+ goto stat_ref;
+ else
+ return -1;
+ }
+ if (starts_with(sb_contents->buf, "refs/") &&
+ !check_refname_format(sb_contents->buf, 0)) {
+ strbuf_swap(sb_contents, symref);
+ *flags |= REF_ISSYMREF;
+ return 0;
+ }
+ }
+
+ /* Is it a directory? */
+ if (S_ISDIR(st.st_mode)) {
+ errno = EISDIR;
+ return -1;
+ }
+
+ /*
+ * Anything else, just open it and try to use it as
+ * a ref
+ */
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ /* inconsistent with lstat; retry */
+ goto stat_ref;
+ else
+ return -1;
+ }
+ strbuf_reset(sb_contents);
+ if (strbuf_read(sb_contents, fd, 256) < 0) {
+ int save_errno = errno;
+ close(fd);
+ errno = save_errno;
+ return -1;
+ }
+ close(fd);
+ strbuf_rtrim(sb_contents);
+ buf = sb_contents->buf;
+ if (starts_with(buf, "ref:")) {
+ buf += 4;
+ while (isspace(*buf))
+ buf++;
+
+ strbuf_reset(symref);
+ strbuf_addstr(symref, buf);
+ *flags |= REF_ISSYMREF;
+ return 0;
+ }
+
+ /*
+ * Please note that FETCH_HEAD has additional
+ * data after the sha.
+ */
+ if (get_sha1_hex(buf, sha1) ||
+ (buf[40] != '\0' && !isspace(buf[40]))) {
+ *flags |= REF_ISBROKEN;
+ errno = EINVAL;
+ return -1;
+ }
+
+ return 0;
+}
+
/* This function needs to return a meaningful errno on failure */
static const char *resolve_ref_1(const char *refname,
int resolve_flags,
@@ -1422,118 +1557,29 @@ static const char *resolve_ref_1(const char *refname,
}
for (symref_count = 0; symref_count < MAXDEPTH; symref_count++) {
- const char *path;
- struct stat st;
- int fd;
+ int read_flags = 0;
- strbuf_reset(sb_path);
- strbuf_git_path(sb_path, "%s", refname);
- path = sb_path->buf;
-
- /*
- * We might have to loop back here to avoid a race
- * condition: first we lstat() the file, then we try
- * to read it as a link or as a file. But if somebody
- * changes the type of the file (file <-> directory
- * <-> symlink) between the lstat() and reading, then
- * we don't want to report that as an error but rather
- * try again starting with the lstat().
- */
- stat_ref:
- if (lstat(path, &st) < 0) {
- if (errno != ENOENT)
+ if (read_raw_ref(refname, sha1, sb_refname,
+ sb_path, sb_contents, &read_flags)) {
+ *flags |= read_flags;
+ if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
return NULL;
- if (resolve_missing_loose_ref(refname, sha1, flags)) {
- if (resolve_flags & RESOLVE_REF_READING) {
- errno = ENOENT;
- return NULL;
- }
- hashclr(sha1);
- }
- if (*flags & REF_BAD_NAME) {
- hashclr(sha1);
+ hashclr(sha1);
+ if (*flags & REF_BAD_NAME)
*flags |= REF_ISBROKEN;
- }
return refname;
}
- /* Follow "normalized" - ie "refs/.." symlinks by hand */
- if (S_ISLNK(st.st_mode)) {
- strbuf_reset(sb_contents);
- if (strbuf_readlink(sb_contents, path, 0) < 0) {
- if (errno == ENOENT || errno == EINVAL)
- /* inconsistent with lstat; retry */
- goto stat_ref;
- else
- return NULL;
- }
- if (starts_with(sb_contents->buf, "refs/") &&
- !check_refname_format(sb_contents->buf, 0)) {
- strbuf_swap(sb_refname, sb_contents);
- refname = sb_refname->buf;
- *flags |= REF_ISSYMREF;
- if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
- hashclr(sha1);
- return refname;
- }
- continue;
- }
- }
+ *flags |= read_flags;
- /* Is it a directory? */
- if (S_ISDIR(st.st_mode)) {
- errno = EISDIR;
- return NULL;
- }
-
- /*
- * Anything else, just open it and try to use it as
- * a ref
- */
- fd = open(path, O_RDONLY);
- if (fd < 0) {
- if (errno == ENOENT)
- /* inconsistent with lstat; retry */
- goto stat_ref;
- else
- return NULL;
- }
- strbuf_reset(sb_contents);
- if (strbuf_read(sb_contents, fd, 256) < 0) {
- int save_errno = errno;
- close(fd);
- errno = save_errno;
- return NULL;
- }
- close(fd);
- strbuf_rtrim(sb_contents);
-
- /*
- * Is it a symbolic ref?
- */
- if (!starts_with(sb_contents->buf, "ref:")) {
- /*
- * Please note that FETCH_HEAD has a second
- * line containing other data.
- */
- if (get_sha1_hex(sb_contents->buf, sha1) ||
- (sb_contents->buf[40] != '\0' && !isspace(sb_contents->buf[40]))) {
- *flags |= REF_ISBROKEN;
- errno = EINVAL;
- return NULL;
- }
+ if (!(read_flags & REF_ISSYMREF)) {
if (*flags & REF_BAD_NAME) {
hashclr(sha1);
*flags |= REF_ISBROKEN;
}
return refname;
}
- *flags |= REF_ISSYMREF;
- refname = sb_contents->buf + 4;
- while (isspace(*refname))
- refname++;
- strbuf_reset(sb_refname);
- strbuf_addstr(sb_refname, refname);
+
refname = sb_refname->buf;
if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
hashclr(sha1);
--
2.8.0.rc3
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