Merge branch 'mh/reflog-expire'

Restructure "reflog expire" to fit the reflogs better with the
recently updated ref API.

Looked reasonable (except that some shortlog entries stood out like
a sore thumb).

* mh/reflog-expire: (24 commits)
  refs.c: let fprintf handle the formatting
  refs.c: don't expose the internal struct ref_lock in the header file
  lock_any_ref_for_update(): inline function
  refs.c: remove unlock_ref/close_ref/commit_ref from the refs api
  reflog_expire(): new function in the reference API
  expire_reflog(): treat the policy callback data as opaque
  Move newlog and last_kept_sha1 to "struct expire_reflog_cb"
  expire_reflog(): move rewrite to flags argument
  expire_reflog(): move verbose to flags argument
  expire_reflog(): pass flags through to expire_reflog_ent()
  struct expire_reflog_cb: a new callback data type
  Rename expire_reflog_cb to expire_reflog_policy_cb
  expire_reflog(): move updateref to flags argument
  expire_reflog(): move dry_run to flags argument
  expire_reflog(): add a "flags" argument
  expire_reflog(): extract two policy-related functions
  Extract function should_expire_reflog_ent()
  expire_reflog(): use a lock_file for rewriting the reflog file
  expire_reflog(): return early if the reference has no reflog
  expire_reflog(): rename "ref" parameter to "refname"
  ...

1 files changed, 181 insertions, 82 deletions

diff --git a/refs.c b/refs.c
index 9edf18b..ab2f2a9 100644
--- a/refs.c
+++ b/refs.c
@@ -6,6 +6,15 @@
 #include "dir.h"
 #include "string-list.h"
 
+struct ref_lock {
+	char *ref_name;
+	char *orig_ref_name;
+	struct lock_file *lk;
+	unsigned char old_sha1[20];
+	int lock_fd;
+	int force_write;
+};
+
 /*
  * How to handle various characters in refnames:
  * 0: An acceptable character for refs
@@ -2093,6 +2102,16 @@ int refname_match(const char *abbrev_name, const char *full_name)
 	return 0;
 }
 
+static void unlock_ref(struct ref_lock *lock)
+{
+	/* Do not free lock->lk -- atexit() still looks at them */
+	if (lock->lk)
+		rollback_lock_file(lock->lk);
+	free(lock->ref_name);
+	free(lock->orig_ref_name);
+	free(lock);
+}
+
 /* This function should make sure errno is meaningful on error */
 static struct ref_lock *verify_lock(struct ref_lock *lock,
 	const unsigned char *old_sha1, int mustexist)
@@ -2345,13 +2364,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-struct ref_lock *lock_any_ref_for_update(const char *refname,
-					 const unsigned char *old_sha1,
-					 int flags, int *type_p)
-{
-	return lock_ref_sha1_basic(refname, old_sha1, NULL, flags, type_p);
-}
-
 /*
  * Write an entry to the packed-refs file for the specified refname.
  * If peeled is non-NULL, write it as the entry's peeled value.
@@ -2900,7 +2912,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 1;
 }
 
-int close_ref(struct ref_lock *lock)
+static int close_ref(struct ref_lock *lock)
 {
 	if (close_lock_file(lock->lk))
 		return -1;
@@ -2908,7 +2920,7 @@ int close_ref(struct ref_lock *lock)
 	return 0;
 }
 
-int commit_ref(struct ref_lock *lock)
+static int commit_ref(struct ref_lock *lock)
 {
 	if (commit_lock_file(lock->lk))
 		return -1;
@@ -2916,16 +2928,6 @@ int commit_ref(struct ref_lock *lock)
 	return 0;
 }
 
-void unlock_ref(struct ref_lock *lock)
-{
-	/* Do not free lock->lk -- atexit() still looks at them */
-	if (lock->lk)
-		rollback_lock_file(lock->lk);
-	free(lock->ref_name);
-	free(lock->orig_ref_name);
-	free(lock);
-}
-
 /*
  * copy the reflog message msg to buf, which has been allocated sufficiently
  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
@@ -3002,15 +3004,37 @@ int log_ref_setup(const char *refname, char *logfile, int bufsize)
 	return 0;
 }
 
+static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
+			    const unsigned char *new_sha1,
+			    const char *committer, const char *msg)
+{
+	int msglen, written;
+	unsigned maxlen, len;
+	char *logrec;
+
+	msglen = msg ? strlen(msg) : 0;
+	maxlen = strlen(committer) + msglen + 100;
+	logrec = xmalloc(maxlen);
+	len = sprintf(logrec, "%s %s %s\n",
+		      sha1_to_hex(old_sha1),
+		      sha1_to_hex(new_sha1),
+		      committer);
+	if (msglen)
+		len += copy_msg(logrec + len - 1, msg) - 1;
+
+	written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
+	free(logrec);
+	if (written != len)
+		return -1;
+
+	return 0;
+}
+
 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
 			 const unsigned char *new_sha1, const char *msg)
 {
-	int logfd, result, written, oflags = O_APPEND | O_WRONLY;
-	unsigned maxlen, len;
-	int msglen;
+	int logfd, result, oflags = O_APPEND | O_WRONLY;
 	char log_file[PATH_MAX];
-	char *logrec;
-	const char *committer;
 
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
@@ -3022,19 +3046,9 @@ static int log_ref_write(const char *refname, const unsigned char *old_sha1,
 	logfd = open(log_file, oflags);
 	if (logfd < 0)
 		return 0;
-	msglen = msg ? strlen(msg) : 0;
-	committer = git_committer_info(0);
-	maxlen = strlen(committer) + msglen + 100;
-	logrec = xmalloc(maxlen);
-	len = sprintf(logrec, "%s %s %s\n",
-		      sha1_to_hex(old_sha1),
-		      sha1_to_hex(new_sha1),
-		      committer);
-	if (msglen)
-		len += copy_msg(logrec + len - 1, msg) - 1;
-	written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
-	free(logrec);
-	if (written != len) {
+	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
+				  git_committer_info(0), msg);
+	if (result) {
 		int save_errno = errno;
 		close(logfd);
 		error("Unable to append to %s", log_file);
@@ -3660,31 +3674,8 @@ int ref_transaction_create(struct ref_transaction *transaction,
 			   int flags, const char *msg,
 			   struct strbuf *err)
 {
-	struct ref_update *update;
-
-	assert(err);
-
-	if (transaction->state != REF_TRANSACTION_OPEN)
-		die("BUG: create called for transaction that is not open");
-
-	if (!new_sha1 || is_null_sha1(new_sha1))
-		die("BUG: create ref with null new_sha1");
-
-	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-		strbuf_addf(err, "refusing to create ref with bad name %s",
-			    refname);
-		return -1;
-	}
-
-	update = add_update(transaction, refname);
-
-	hashcpy(update->new_sha1, new_sha1);
-	hashclr(update->old_sha1);
-	update->flags = flags;
-	update->have_old = 1;
-	if (msg)
-		update->msg = xstrdup(msg);
-	return 0;
+	return ref_transaction_update(transaction, refname, new_sha1,
+				      null_sha1, flags, 1, msg, err);
 }
 
 int ref_transaction_delete(struct ref_transaction *transaction,
@@ -3693,26 +3684,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 			   int flags, int have_old, const char *msg,
 			   struct strbuf *err)
 {
-	struct ref_update *update;
-
-	assert(err);
-
-	if (transaction->state != REF_TRANSACTION_OPEN)
-		die("BUG: delete called for transaction that is not open");
-
-	if (have_old && !old_sha1)
-		die("BUG: have_old is true but old_sha1 is NULL");
-
-	update = add_update(transaction, refname);
-	update->flags = flags;
-	update->have_old = have_old;
-	if (have_old) {
-		assert(!is_null_sha1(old_sha1));
-		hashcpy(update->old_sha1, old_sha1);
-	}
-	if (msg)
-		update->msg = xstrdup(msg);
-	return 0;
+	return ref_transaction_update(transaction, refname, null_sha1,
+				      old_sha1, flags, have_old, msg, err);
 }
 
 int update_ref(const char *action, const char *refname,
@@ -4008,3 +3981,129 @@ int ref_is_hidden(const char *refname)
 	}
 	return 0;
 }
+
+struct expire_reflog_cb {
+	unsigned int flags;
+	reflog_expiry_should_prune_fn *should_prune_fn;
+	void *policy_cb;
+	FILE *newlog;
+	unsigned char last_kept_sha1[20];
+};
+
+static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+			     const char *email, unsigned long timestamp, int tz,
+			     const char *message, void *cb_data)
+{
+	struct expire_reflog_cb *cb = cb_data;
+	struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
+
+	if (cb->flags & EXPIRE_REFLOGS_REWRITE)
+		osha1 = cb->last_kept_sha1;
+
+	if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
+				   message, policy_cb)) {
+		if (!cb->newlog)
+			printf("would prune %s", message);
+		else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
+			printf("prune %s", message);
+	} else {
+		if (cb->newlog) {
+			fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
+				sha1_to_hex(osha1), sha1_to_hex(nsha1),
+				email, timestamp, tz, message);
+			hashcpy(cb->last_kept_sha1, nsha1);
+		}
+		if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
+			printf("keep %s", message);
+	}
+	return 0;
+}
+
+int reflog_expire(const char *refname, const unsigned char *sha1,
+		 unsigned int flags,
+		 reflog_expiry_prepare_fn prepare_fn,
+		 reflog_expiry_should_prune_fn should_prune_fn,
+		 reflog_expiry_cleanup_fn cleanup_fn,
+		 void *policy_cb_data)
+{
+	static struct lock_file reflog_lock;
+	struct expire_reflog_cb cb;
+	struct ref_lock *lock;
+	char *log_file;
+	int status = 0;
+
+	memset(&cb, 0, sizeof(cb));
+	cb.flags = flags;
+	cb.policy_cb = policy_cb_data;
+	cb.should_prune_fn = should_prune_fn;
+
+	/*
+	 * The reflog file is locked by holding the lock on the
+	 * reference itself, plus we might need to update the
+	 * reference if --updateref was specified:
+	 */
+	lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, NULL);
+	if (!lock)
+		return error("cannot lock ref '%s'", refname);
+	if (!reflog_exists(refname)) {
+		unlock_ref(lock);
+		return 0;
+	}
+
+	log_file = git_pathdup("logs/%s", refname);
+	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+		/*
+		 * Even though holding $GIT_DIR/logs/$reflog.lock has
+		 * no locking implications, we use the lock_file
+		 * machinery here anyway because it does a lot of the
+		 * work we need, including cleaning up if the program
+		 * exits unexpectedly.
+		 */
+		if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
+			struct strbuf err = STRBUF_INIT;
+			unable_to_lock_message(log_file, errno, &err);
+			error("%s", err.buf);
+			strbuf_release(&err);
+			goto failure;
+		}
+		cb.newlog = fdopen_lock_file(&reflog_lock, "w");
+		if (!cb.newlog) {
+			error("cannot fdopen %s (%s)",
+			      reflog_lock.filename.buf, strerror(errno));
+			goto failure;
+		}
+	}
+
+	(*prepare_fn)(refname, sha1, cb.policy_cb);
+	for_each_reflog_ent(refname, expire_reflog_ent, &cb);
+	(*cleanup_fn)(cb.policy_cb);
+
+	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+		if (close_lock_file(&reflog_lock)) {
+			status |= error("couldn't write %s: %s", log_file,
+					strerror(errno));
+		} else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) &&
+			(write_in_full(lock->lock_fd,
+				sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
+			 write_str_in_full(lock->lock_fd, "\n") != 1 ||
+			 close_ref(lock) < 0)) {
+			status |= error("couldn't write %s",
+					lock->lk->filename.buf);
+			rollback_lock_file(&reflog_lock);
+		} else if (commit_lock_file(&reflog_lock)) {
+			status |= error("unable to commit reflog '%s' (%s)",
+					log_file, strerror(errno));
+		} else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) && commit_ref(lock)) {
+			status |= error("couldn't set %s", lock->ref_name);
+		}
+	}
+	free(log_file);
+	unlock_ref(lock);
+	return status;
+
+ failure:
+	rollback_lock_file(&reflog_lock);
+	free(log_file);
+	unlock_ref(lock);
+	return -1;
+}