Created 'struct ref_lock' to contain the data necessary to perform
a ref update. This change improves writing a ref as the file names
are generated only once (rather than twice) and supports following
symrefs (up to the maximum depth). Further the ref_lock structure
provides room to extend the update API with ref logging.
Signed-off-by: Shawn O. Pearce <spearce@xxxxxxxxxxx>
---
fetch.c | 32 +++++----
refs.c | 236 ++++++++++++++++++++++++++++++---------------------------------
refs.h | 24 ++++--
3 files changed, 144 insertions(+), 148 deletions(-)
d38945e0c759f8739da4c24485578a8193d54c59
diff --git a/fetch.c b/fetch.c
index 73bde07..8bdaacb 100644
--- a/fetch.c
+++ b/fetch.c
@@ -204,14 +204,14 @@ static int mark_complete(const char *pat
int pull(char *target)
{
+ struct ref_lock *lock;
unsigned char sha1[20];
- int fd = -1;
save_commit_buffer = 0;
track_object_refs = 0;
- if (write_ref && current_ref) {
- fd = lock_ref_sha1(write_ref, current_ref);
- if (fd < 0)
+ if (write_ref) {
+ lock = lock_ref_sha1(write_ref, current_ref, 1);
+ if (!lock)
return -1;
}
@@ -219,20 +219,22 @@ int pull(char *target)
for_each_ref(mark_complete);
}
- if (interpret_target(target, sha1))
- return error("Could not interpret %s as something to pull",
- target);
- if (process(lookup_unknown_object(sha1)))
+ if (interpret_target(target, sha1)) {
+ error("Could not interpret %s as something to pull", target);
+ unlock_ref(lock);
+ return -1;
+ }
+ if (process(lookup_unknown_object(sha1))) {
+ unlock_ref(lock);
return -1;
- if (loop())
+ }
+ if (loop()) {
+ unlock_ref(lock);
return -1;
-
+ }
+
if (write_ref) {
- if (current_ref) {
- write_ref_sha1(write_ref, fd, sha1);
- } else {
- write_ref_sha1_unlocked(write_ref, sha1);
- }
+ return write_ref_sha1(lock, sha1, "git fetch");
}
return 0;
}
diff --git a/refs.c b/refs.c
index 0f3491f..91c8c44 100644
--- a/refs.c
+++ b/refs.c
@@ -198,26 +198,6 @@ int for_each_remote_ref(int (*fn)(const
return do_for_each_ref("refs/remotes", fn, 13);
}
-static char *ref_file_name(const char *ref)
-{
- char *base = get_refs_directory();
- int baselen = strlen(base);
- int reflen = strlen(ref);
- char *ret = xmalloc(baselen + 2 + reflen);
- sprintf(ret, "%s/%s", base, ref);
- return ret;
-}
-
-static char *ref_lock_file_name(const char *ref)
-{
- char *base = get_refs_directory();
- int baselen = strlen(base);
- int reflen = strlen(ref);
- char *ret = xmalloc(baselen + 7 + reflen);
- sprintf(ret, "%s/%s.lock", base, ref);
- return ret;
-}
-
int get_ref_sha1(const char *ref, unsigned char *sha1)
{
if (check_ref_format(ref))
@@ -225,94 +205,6 @@ int get_ref_sha1(const char *ref, unsign
return read_ref(git_path("refs/%s", ref), sha1);
}
-static int lock_ref_file(const char *filename, const char *lock_filename,
- const unsigned char *old_sha1)
-{
- int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
- unsigned char current_sha1[20];
- int retval;
- if (fd < 0) {
- return error("Couldn't open lock file for %s: %s",
- filename, strerror(errno));
- }
- retval = read_ref(filename, current_sha1);
- if (old_sha1) {
- if (retval) {
- close(fd);
- unlink(lock_filename);
- return error("Could not read the current value of %s",
- filename);
- }
- if (memcmp(current_sha1, old_sha1, 20)) {
- close(fd);
- unlink(lock_filename);
- error("The current value of %s is %s",
- filename, sha1_to_hex(current_sha1));
- return error("Expected %s",
- sha1_to_hex(old_sha1));
- }
- } else {
- if (!retval) {
- close(fd);
- unlink(lock_filename);
- return error("Unexpectedly found a value of %s for %s",
- sha1_to_hex(current_sha1), filename);
- }
- }
- return fd;
-}
-
-int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
-{
- char *filename;
- char *lock_filename;
- int retval;
- if (check_ref_format(ref))
- return -1;
- filename = ref_file_name(ref);
- lock_filename = ref_lock_file_name(ref);
- retval = lock_ref_file(filename, lock_filename, old_sha1);
- free(filename);
- free(lock_filename);
- return retval;
-}
-
-static int write_ref_file(const char *filename,
- const char *lock_filename, int fd,
- const unsigned char *sha1)
-{
- char *hex = sha1_to_hex(sha1);
- char term = '\n';
- if (write(fd, hex, 40) < 40 ||
- write(fd, &term, 1) < 1) {
- error("Couldn't write %s", filename);
- close(fd);
- return -1;
- }
- close(fd);
- rename(lock_filename, filename);
- return 0;
-}
-
-int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
-{
- char *filename;
- char *lock_filename;
- int retval;
- if (fd < 0)
- return -1;
- if (check_ref_format(ref))
- return -1;
- filename = ref_file_name(ref);
- lock_filename = ref_lock_file_name(ref);
- if (safe_create_leading_directories(filename))
- die("unable to create leading directory for %s", filename);
- retval = write_ref_file(filename, lock_filename, fd, sha1);
- free(filename);
- free(lock_filename);
- return retval;
-}
-
/*
* Make sure "ref" is something reasonable to have under ".git/refs/";
* We do not like it if:
@@ -365,25 +257,119 @@ int check_ref_format(const char *ref)
}
}
-int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
+static struct ref_lock* verify_lock(struct ref_lock *lock,
+ const unsigned char *old_sha1, int mustexist)
+{
+ char buf[40];
+ int nr, fd = open(lock->ref_file, O_RDONLY);
+ if (fd < 0 && (mustexist || errno != ENOENT)) {
+ error("Can't verify ref %s", lock->ref_file);
+ unlock_ref(lock);
+ return NULL;
+ }
+ nr = read(fd, buf, 40);
+ close(fd);
+ if (nr != 40 || get_sha1_hex(buf, lock->old_sha1) < 0) {
+ error("Can't verify ref %s", lock->ref_file);
+ unlock_ref(lock);
+ return NULL;
+ }
+ if (memcmp(lock->old_sha1, old_sha1, 20)) {
+ error("Ref %s is at %s but expected %s", lock->ref_file,
+ sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
+ unlock_ref(lock);
+ return NULL;
+ }
+ return lock;
+}
+
+static struct ref_lock* lock_ref_sha1_basic(const char *path,
+ int plen,
+ const unsigned char *old_sha1, int mustexist)
+{
+ struct ref_lock *lock;
+
+ lock = xcalloc(1, sizeof(struct ref_lock));
+ lock->lock_fd = -1;
+
+ plen = strlen(path) - plen;
+ path = resolve_ref(path, lock->old_sha1, mustexist);
+ if (!path) {
+ error("Can't read ref %s", path);
+ unlock_ref(lock);
+ return NULL;
+ }
+
+ lock->ref_file = strdup(path);
+ lock->lock_file = strdup(mkpath("%s.lock", lock->ref_file));
+
+ if (safe_create_leading_directories(lock->lock_file))
+ die("unable to create directory for %s", lock->lock_file);
+ lock->lock_fd = open(lock->lock_file,
+ O_WRONLY | O_CREAT | O_EXCL, 0666);
+ if (lock->lock_fd < 0) {
+ error("Couldn't open lock file %s: %s",
+ lock->lock_file, strerror(errno));
+ unlock_ref(lock);
+ return NULL;
+ }
+
+ return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
+}
+
+struct ref_lock* lock_ref_sha1(const char *ref,
+ const unsigned char *old_sha1, int mustexist)
{
- char *filename;
- char *lock_filename;
- int fd;
- int retval;
if (check_ref_format(ref))
+ return NULL;
+ return lock_ref_sha1_basic(git_path("refs/%s", ref),
+ strlen(ref), old_sha1, mustexist);
+}
+
+struct ref_lock* lock_any_ref_for_update(const char *ref,
+ const unsigned char *old_sha1, int mustexist)
+{
+ return lock_ref_sha1_basic(git_path("%s", ref),
+ strlen(ref), old_sha1, mustexist);
+}
+
+void unlock_ref (struct ref_lock *lock)
+{
+ if (lock->lock_fd >= 0) {
+ close(lock->lock_fd);
+ unlink(lock->lock_file);
+ }
+ if (lock->ref_file)
+ free(lock->ref_file);
+ if (lock->lock_file)
+ free(lock->lock_file);
+ free(lock);
+}
+
+int write_ref_sha1(struct ref_lock *lock,
+ const unsigned char *sha1, const char *logmsg)
+{
+ static char term = '\n';
+
+ if (!lock)
return -1;
- filename = ref_file_name(ref);
- lock_filename = ref_lock_file_name(ref);
- if (safe_create_leading_directories(filename))
- die("unable to create leading directory for %s", filename);
- fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
- if (fd < 0) {
- error("Writing %s", lock_filename);
- perror("Open");
+ if (!memcmp(lock->old_sha1, sha1, 20)) {
+ unlock_ref(lock);
+ return 0;
}
- retval = write_ref_file(filename, lock_filename, fd, sha1);
- free(filename);
- free(lock_filename);
- return retval;
+ if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
+ write(lock->lock_fd, &term, 1) != 1
+ || close(lock->lock_fd) < 0) {
+ error("Couldn't write %s", lock->lock_file);
+ unlock_ref(lock);
+ return -1;
+ }
+ if (rename(lock->lock_file, lock->ref_file) < 0) {
+ error("Couldn't set %s", lock->ref_file);
+ unlock_ref(lock);
+ return -1;
+ }
+ lock->lock_fd = -1;
+ unlock_ref(lock);
+ return 0;
}
diff --git a/refs.h b/refs.h
index fa816c1..b7e9df2 100644
--- a/refs.h
+++ b/refs.h
@@ -1,6 +1,13 @@
#ifndef REFS_H
#define REFS_H
+struct ref_lock {
+ char *ref_file;
+ char *lock_file;
+ unsigned char old_sha1[20];
+ int lock_fd;
+};
+
/*
* Calls the specified function for each ref file until it returns nonzero,
* and returns the value
@@ -14,16 +21,17 @@ extern int for_each_remote_ref(int (*fn)
/** Reads the refs file specified into sha1 **/
extern int get_ref_sha1(const char *ref, unsigned char *sha1);
-/** Locks ref and returns the fd to give to write_ref_sha1() if the ref
- * has the given value currently; otherwise, returns -1.
- **/
-extern int lock_ref_sha1(const char *ref, const unsigned char *old_sha1);
+/** Locks a "refs/" ref returning the lock on success and NULL on failure. **/
+extern struct ref_lock* lock_ref_sha1(const char *ref, const unsigned char *old_sha1, int mustexist);
+
+/** Locks any ref (for 'HEAD' type refs). */
+extern struct ref_lock* lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int mustexist);
-/** Writes sha1 into the refs file specified, locked with the given fd. **/
-extern int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1);
+/** Release any lock taken but not written. **/
+extern void unlock_ref (struct ref_lock *lock);
-/** Writes sha1 into the refs file specified. **/
-extern int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1);
+/** Writes sha1 into the ref specified by the lock. **/
+extern int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, const char *msg);
/** Returns 0 if target has the right format for a ref. **/
extern int check_ref_format(const char *target);
--
1.3.2.g7278
-
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