Merge branch 'rs/ref-transaction-1'
authorJunio C Hamano <gitster@pobox.com>
Thu, 11 Sep 2014 17:33:30 +0000 (10:33 -0700)
committerJunio C Hamano <gitster@pobox.com>
Thu, 11 Sep 2014 17:33:31 +0000 (10:33 -0700)
The second batch of the transactional ref update series.

* rs/ref-transaction-1: (22 commits)
update-ref --stdin: pass transaction around explicitly
update-ref --stdin: narrow scope of err strbuf
refs.c: make delete_ref use a transaction
refs.c: make prune_ref use a transaction to delete the ref
refs.c: remove lock_ref_sha1
refs.c: remove the update_ref_write function
refs.c: remove the update_ref_lock function
refs.c: make lock_ref_sha1 static
walker.c: use ref transaction for ref updates
fast-import.c: use a ref transaction when dumping tags
receive-pack.c: use a reference transaction for updating the refs
refs.c: change update_ref to use a transaction
branch.c: use ref transaction for all ref updates
fast-import.c: change update_branch to use ref transactions
sequencer.c: use ref transactions for all ref updates
commit.c: use ref transactions for updates
replace.c: use the ref transaction functions for updates
tag.c: use ref transactions when doing updates
refs.c: add transaction.status and track OPEN/CLOSED
refs.c: make ref_transaction_begin take an err argument
...

branch.c
builtin/commit.c
builtin/receive-pack.c
builtin/replace.c
builtin/tag.c
builtin/update-ref.c
fast-import.c
refs.c
refs.h
sequencer.c
walker.c
index df6b1203de75618fd7aaff28f7f38ecbcd82066e..9a2228ebb46df721741db2249ab25cce5dfb4282 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -210,7 +210,6 @@ void create_branch(const char *head,
                   int force, int reflog, int clobber_head,
                   int quiet, enum branch_track track)
 {
-       struct ref_lock *lock = NULL;
        struct commit *commit;
        unsigned char sha1[20];
        char *real_ref, msg[PATH_MAX + 20];
@@ -269,15 +268,6 @@ void create_branch(const char *head,
                die(_("Not a valid branch point: '%s'."), start_name);
        hashcpy(sha1, commit->object.sha1);
 
-       if (!dont_change_ref) {
-               lock = lock_any_ref_for_update(ref.buf, NULL, 0, NULL);
-               if (!lock)
-                       die_errno(_("Failed to lock ref for update"));
-       }
-
-       if (reflog)
-               log_all_ref_updates = 1;
-
        if (forcing)
                snprintf(msg, sizeof msg, "branch: Reset to %s",
                         start_name);
@@ -285,13 +275,26 @@ void create_branch(const char *head,
                snprintf(msg, sizeof msg, "branch: Created from %s",
                         start_name);
 
+       if (reflog)
+               log_all_ref_updates = 1;
+
+       if (!dont_change_ref) {
+               struct ref_transaction *transaction;
+               struct strbuf err = STRBUF_INIT;
+
+               transaction = ref_transaction_begin(&err);
+               if (!transaction ||
+                   ref_transaction_update(transaction, ref.buf, sha1,
+                                          null_sha1, 0, !forcing, &err) ||
+                   ref_transaction_commit(transaction, msg, &err))
+                       die("%s", err.buf);
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
+       }
+
        if (real_ref && track)
                setup_tracking(ref.buf + 11, real_ref, track, quiet);
 
-       if (!dont_change_ref)
-               if (write_ref_sha1(lock, sha1, msg) < 0)
-                       die_errno(_("Failed to write ref"));
-
        strbuf_release(&ref);
        free(real_ref);
 }
index ec0048e8b05d5a54e1507b9a8f3e73f06be0fa39..5911447486f5b2325dff4747872a25dd4325c1e2 100644 (file)
@@ -1651,11 +1651,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
        const char *index_file, *reflog_msg;
        char *nl;
        unsigned char sha1[20];
-       struct ref_lock *ref_lock;
        struct commit_list *parents = NULL, **pptr = &parents;
        struct stat statbuf;
        struct commit *current_head = NULL;
        struct commit_extra_header *extra = NULL;
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
 
        if (argc == 2 && !strcmp(argv[1], "-h"))
                usage_with_options(builtin_commit_usage, builtin_commit_options);
@@ -1777,16 +1778,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
        strbuf_release(&author_ident);
        free_commit_extra_headers(extra);
 
-       ref_lock = lock_any_ref_for_update("HEAD",
-                                          !current_head
-                                          ? NULL
-                                          : current_head->object.sha1,
-                                          0, NULL);
-       if (!ref_lock) {
-               rollback_index_files();
-               die(_("cannot lock HEAD ref"));
-       }
-
        nl = strchr(sb.buf, '\n');
        if (nl)
                strbuf_setlen(&sb, nl + 1 - sb.buf);
@@ -1795,10 +1786,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
        strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
        strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
 
-       if (write_ref_sha1(ref_lock, sha1, sb.buf) < 0) {
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_update(transaction, "HEAD", sha1,
+                                  current_head
+                                  ? current_head->object.sha1 : NULL,
+                                  0, !!current_head, &err) ||
+           ref_transaction_commit(transaction, sb.buf, &err)) {
                rollback_index_files();
-               die(_("cannot update HEAD ref"));
+               die("%s", err.buf);
        }
+       ref_transaction_free(transaction);
 
        unlink(git_path("CHERRY_PICK_HEAD"));
        unlink(git_path("REVERT_HEAD"));
@@ -1827,5 +1825,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
        if (!quiet)
                print_summary(prefix, sha1, !current_head);
 
+       strbuf_release(&err);
        return 0;
 }
index 5ad9075b3c4b378366f5146ea204160b76859d46..afb8d9926496de2bed8bcab793dd79562e575e18 100644 (file)
@@ -473,7 +473,6 @@ static const char *update(struct command *cmd, struct shallow_info *si)
        const char *namespaced_name;
        unsigned char *old_sha1 = cmd->old_sha1;
        unsigned char *new_sha1 = cmd->new_sha1;
-       struct ref_lock *lock;
 
        /* only refs/... are allowed */
        if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -574,19 +573,27 @@ static const char *update(struct command *cmd, struct shallow_info *si)
                return NULL; /* good */
        }
        else {
+               struct strbuf err = STRBUF_INIT;
+               struct ref_transaction *transaction;
+
                if (shallow_update && si->shallow_ref[cmd->index] &&
                    update_shallow_ref(cmd, si))
                        return "shallow error";
 
-               lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-                                              0, NULL);
-               if (!lock) {
-                       rp_error("failed to lock %s", name);
-                       return "failed to lock";
-               }
-               if (write_ref_sha1(lock, new_sha1, "push")) {
-                       return "failed to write"; /* error() already called */
+               transaction = ref_transaction_begin(&err);
+               if (!transaction ||
+                   ref_transaction_update(transaction, namespaced_name,
+                                          new_sha1, old_sha1, 0, 1, &err) ||
+                   ref_transaction_commit(transaction, "push", &err)) {
+                       ref_transaction_free(transaction);
+
+                       rp_error("%s", err.buf);
+                       strbuf_release(&err);
+                       return "failed to update ref";
                }
+
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
                return NULL; /* good */
        }
 }
index d2aac642606e1f1614b5b6c7f83707b4fedac87d..8020db850092691f55df3815173a6eefce0ca6a0 100644 (file)
@@ -155,7 +155,8 @@ static int replace_object_sha1(const char *object_ref,
        unsigned char prev[20];
        enum object_type obj_type, repl_type;
        char ref[PATH_MAX];
-       struct ref_lock *lock;
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
 
        obj_type = sha1_object_info(object, NULL);
        repl_type = sha1_object_info(repl, NULL);
@@ -168,12 +169,13 @@ static int replace_object_sha1(const char *object_ref,
 
        check_ref_valid(object, prev, ref, sizeof(ref), force);
 
-       lock = lock_any_ref_for_update(ref, prev, 0, NULL);
-       if (!lock)
-               die("%s: cannot lock the ref", ref);
-       if (write_ref_sha1(lock, repl, NULL) < 0)
-               die("%s: cannot update the ref", ref);
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_update(transaction, ref, repl, prev, 0, 1, &err) ||
+           ref_transaction_commit(transaction, NULL, &err))
+               die("%s", err.buf);
 
+       ref_transaction_free(transaction);
        return 0;
 }
 
index 19eb7478208d7e9c88ced92f2620572d2b234974..a81b9e4174c77fc10d9f0a37c547723505208c3c 100644 (file)
@@ -576,7 +576,6 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
        struct strbuf ref = STRBUF_INIT;
        unsigned char object[20], prev[20];
        const char *object_ref, *tag;
-       struct ref_lock *lock;
        struct create_tag_options opt;
        char *cleanup_arg = NULL;
        int annotate = 0, force = 0, lines = -1;
@@ -584,6 +583,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
        const char *msgfile = NULL, *keyid = NULL;
        struct msg_arg msg = { 0, STRBUF_INIT };
        struct commit_list *with_commit = NULL;
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
        struct option options[] = {
                OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
                { OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
@@ -729,14 +730,17 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
        if (annotate)
                create_tag(object, tag, &buf, &opt, prev, object);
 
-       lock = lock_any_ref_for_update(ref.buf, prev, 0, NULL);
-       if (!lock)
-               die(_("%s: cannot lock the ref"), ref.buf);
-       if (write_ref_sha1(lock, object, NULL) < 0)
-               die(_("%s: cannot update the ref"), ref.buf);
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_update(transaction, ref.buf, object, prev,
+                                  0, 1, &err) ||
+           ref_transaction_commit(transaction, NULL, &err))
+               die("%s", err.buf);
+       ref_transaction_free(transaction);
        if (force && !is_null_sha1(prev) && hashcmp(prev, object))
                printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
+       strbuf_release(&err);
        strbuf_release(&buf);
        strbuf_release(&ref);
        return 0;
index 3067b11310fb01e9e05a1988898566f211601e07..54a48c0cfaab57122fc7ce57c525638c2c95408c 100644 (file)
@@ -12,11 +12,8 @@ static const char * const git_update_ref_usage[] = {
        NULL
 };
 
-static struct ref_transaction *transaction;
-
 static char line_termination = '\n';
 static int update_flags;
-static struct strbuf err = STRBUF_INIT;
 
 /*
  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
@@ -177,8 +174,10 @@ static int parse_next_sha1(struct strbuf *input, const char **next,
  * depending on how line_termination is set.
  */
 
-static const char *parse_cmd_update(struct strbuf *input, const char *next)
+static const char *parse_cmd_update(struct ref_transaction *transaction,
+                                   struct strbuf *input, const char *next)
 {
+       struct strbuf err = STRBUF_INIT;
        char *refname;
        unsigned char new_sha1[20];
        unsigned char old_sha1[20];
@@ -204,12 +203,15 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
 
        update_flags = 0;
        free(refname);
+       strbuf_release(&err);
 
        return next;
 }
 
-static const char *parse_cmd_create(struct strbuf *input, const char *next)
+static const char *parse_cmd_create(struct ref_transaction *transaction,
+                                   struct strbuf *input, const char *next)
 {
+       struct strbuf err = STRBUF_INIT;
        char *refname;
        unsigned char new_sha1[20];
 
@@ -226,16 +228,21 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
        if (*next != line_termination)
                die("create %s: extra input: %s", refname, next);
 
-       ref_transaction_create(transaction, refname, new_sha1, update_flags);
+       if (ref_transaction_create(transaction, refname, new_sha1,
+                                  update_flags, &err))
+               die("%s", err.buf);
 
        update_flags = 0;
        free(refname);
+       strbuf_release(&err);
 
        return next;
 }
 
-static const char *parse_cmd_delete(struct strbuf *input, const char *next)
+static const char *parse_cmd_delete(struct ref_transaction *transaction,
+                                   struct strbuf *input, const char *next)
 {
+       struct strbuf err = STRBUF_INIT;
        char *refname;
        unsigned char old_sha1[20];
        int have_old;
@@ -256,17 +263,21 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
        if (*next != line_termination)
                die("delete %s: extra input: %s", refname, next);
 
-       ref_transaction_delete(transaction, refname, old_sha1,
-                              update_flags, have_old);
+       if (ref_transaction_delete(transaction, refname, old_sha1,
+                                  update_flags, have_old, &err))
+               die("%s", err.buf);
 
        update_flags = 0;
        free(refname);
+       strbuf_release(&err);
 
        return next;
 }
 
-static const char *parse_cmd_verify(struct strbuf *input, const char *next)
+static const char *parse_cmd_verify(struct ref_transaction *transaction,
+                                   struct strbuf *input, const char *next)
 {
+       struct strbuf err = STRBUF_INIT;
        char *refname;
        unsigned char new_sha1[20];
        unsigned char old_sha1[20];
@@ -294,6 +305,7 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
 
        update_flags = 0;
        free(refname);
+       strbuf_release(&err);
 
        return next;
 }
@@ -307,7 +319,7 @@ static const char *parse_cmd_option(struct strbuf *input, const char *next)
        return next + 8;
 }
 
-static void update_refs_stdin(void)
+static void update_refs_stdin(struct ref_transaction *transaction)
 {
        struct strbuf input = STRBUF_INIT;
        const char *next;
@@ -322,13 +334,13 @@ static void update_refs_stdin(void)
                else if (isspace(*next))
                        die("whitespace before command: %s", next);
                else if (starts_with(next, "update "))
-                       next = parse_cmd_update(&input, next + 7);
+                       next = parse_cmd_update(transaction, &input, next + 7);
                else if (starts_with(next, "create "))
-                       next = parse_cmd_create(&input, next + 7);
+                       next = parse_cmd_create(transaction, &input, next + 7);
                else if (starts_with(next, "delete "))
-                       next = parse_cmd_delete(&input, next + 7);
+                       next = parse_cmd_delete(transaction, &input, next + 7);
                else if (starts_with(next, "verify "))
-                       next = parse_cmd_verify(&input, next + 7);
+                       next = parse_cmd_verify(transaction, &input, next + 7);
                else if (starts_with(next, "option "))
                        next = parse_cmd_option(&input, next + 7);
                else
@@ -362,15 +374,21 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
                die("Refusing to perform update with empty message.");
 
        if (read_stdin) {
-               transaction = ref_transaction_begin();
+               struct strbuf err = STRBUF_INIT;
+               struct ref_transaction *transaction;
+
+               transaction = ref_transaction_begin(&err);
+               if (!transaction)
+                       die("%s", err.buf);
                if (delete || no_deref || argc > 0)
                        usage_with_options(git_update_ref_usage, options);
                if (end_null)
                        line_termination = '\0';
-               update_refs_stdin();
+               update_refs_stdin(transaction);
                if (ref_transaction_commit(transaction, msg, &err))
                        die("%s", err.buf);
                ref_transaction_free(transaction);
+               strbuf_release(&err);
                return 0;
        }
 
index 34e780dcd0ddaa98790f76eed7c515affe61c384..2b31053e0d916ce8b9379a1cde9345f3e265d188 100644 (file)
@@ -1679,8 +1679,9 @@ static int tree_content_get(
 static int update_branch(struct branch *b)
 {
        static const char *msg = "fast-import";
-       struct ref_lock *lock;
+       struct ref_transaction *transaction;
        unsigned char old_sha1[20];
+       struct strbuf err = STRBUF_INIT;
 
        if (read_ref(b->name, old_sha1))
                hashclr(old_sha1);
@@ -1689,29 +1690,33 @@ static int update_branch(struct branch *b)
                        delete_ref(b->name, old_sha1, 0);
                return 0;
        }
-       lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
-       if (!lock)
-               return error("Unable to lock %s", b->name);
        if (!force_update && !is_null_sha1(old_sha1)) {
                struct commit *old_cmit, *new_cmit;
 
                old_cmit = lookup_commit_reference_gently(old_sha1, 0);
                new_cmit = lookup_commit_reference_gently(b->sha1, 0);
-               if (!old_cmit || !new_cmit) {
-                       unlock_ref(lock);
+               if (!old_cmit || !new_cmit)
                        return error("Branch %s is missing commits.", b->name);
-               }
 
                if (!in_merge_bases(old_cmit, new_cmit)) {
-                       unlock_ref(lock);
                        warning("Not updating %s"
                                " (new tip %s does not contain %s)",
                                b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
                        return -1;
                }
        }
-       if (write_ref_sha1(lock, b->sha1, msg) < 0)
-               return error("Unable to update %s", b->name);
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
+                                  0, 1, &err) ||
+           ref_transaction_commit(transaction, msg, &err)) {
+               ref_transaction_free(transaction);
+               error("%s", err.buf);
+               strbuf_release(&err);
+               return -1;
+       }
+       ref_transaction_free(transaction);
+       strbuf_release(&err);
        return 0;
 }
 
@@ -1730,15 +1735,32 @@ static void dump_tags(void)
 {
        static const char *msg = "fast-import";
        struct tag *t;
-       struct ref_lock *lock;
-       char ref_name[PATH_MAX];
+       struct strbuf ref_name = STRBUF_INIT;
+       struct strbuf err = STRBUF_INIT;
+       struct ref_transaction *transaction;
 
+       transaction = ref_transaction_begin(&err);
+       if (!transaction) {
+               failure |= error("%s", err.buf);
+               goto cleanup;
+       }
        for (t = first_tag; t; t = t->next_tag) {
-               sprintf(ref_name, "tags/%s", t->name);
-               lock = lock_ref_sha1(ref_name, NULL);
-               if (!lock || write_ref_sha1(lock, t->sha1, msg) < 0)
-                       failure |= error("Unable to update %s", ref_name);
+               strbuf_reset(&ref_name);
+               strbuf_addf(&ref_name, "refs/tags/%s", t->name);
+
+               if (ref_transaction_update(transaction, ref_name.buf, t->sha1,
+                                          NULL, 0, 0, &err)) {
+                       failure |= error("%s", err.buf);
+                       goto cleanup;
+               }
        }
+       if (ref_transaction_commit(transaction, msg, &err))
+               failure |= error("%s", err.buf);
+
+ cleanup:
+       ref_transaction_free(transaction);
+       strbuf_release(&ref_name);
+       strbuf_release(&err);
 }
 
 static void dump_marks_helper(FILE *f,
diff --git a/refs.c b/refs.c
index 27927f2319130cc0575817542dfd47c37cc5149b..808e261c235b9803a80faefd79a6329cebcf5fc1 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -24,6 +24,11 @@ static unsigned char refname_disposition[256] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
 };
 
+/*
+ * Used as a flag to ref_transaction_delete when a loose ref is being
+ * pruned.
+ */
+#define REF_ISPRUNING  0x0100
 /*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
@@ -2068,7 +2073,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
        return logs_found;
 }
 
-/* This function should make sure errno is meaningful on error */
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
                                            const unsigned char *old_sha1,
                                            int flags, int *type_p)
@@ -2169,15 +2177,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
        return NULL;
 }
 
-struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
-{
-       char refpath[PATH_MAX];
-       if (check_refname_format(refname, 0))
-               return NULL;
-       strcpy(refpath, mkpath("refs/%s", refname));
-       return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
-}
-
 struct ref_lock *lock_any_ref_for_update(const char *refname,
                                         const unsigned char *old_sha1,
                                         int flags, int *type_p)
@@ -2387,13 +2386,25 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-       struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
 
-       if (lock) {
-               unlink_or_warn(git_path("%s", r->name));
-               unlock_ref(lock);
-               try_remove_empty_parents(r->name);
+       if (check_refname_format(r->name + 5, 0))
+               return;
+
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_delete(transaction, r->name, r->sha1,
+                                  REF_ISPRUNING, 1, &err) ||
+           ref_transaction_commit(transaction, NULL, &err)) {
+               ref_transaction_free(transaction);
+               error("%s", err.buf);
+               strbuf_release(&err);
+               return;
        }
+       ref_transaction_free(transaction);
+       strbuf_release(&err);
+       try_remove_empty_parents(r->name);
 }
 
 static void prune_refs(struct ref_to_prune *r)
@@ -2536,11 +2547,6 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
        return ret;
 }
 
-static int repack_without_ref(const char *refname)
-{
-       return repack_without_refs(&refname, 1, NULL);
-}
-
 static int delete_ref_loose(struct ref_lock *lock, int flag)
 {
        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
@@ -2558,24 +2564,22 @@ static int delete_ref_loose(struct ref_lock *lock, int flag)
 
 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 {
-       struct ref_lock *lock;
-       int ret = 0, flag = 0;
-
-       lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
-       if (!lock)
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
+
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_delete(transaction, refname, sha1, delopt,
+                                  sha1 && !is_null_sha1(sha1), &err) ||
+           ref_transaction_commit(transaction, NULL, &err)) {
+               error("%s", err.buf);
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
                return 1;
-       ret |= delete_ref_loose(lock, flag);
-
-       /* removing the loose one could have resurrected an earlier
-        * packed one.  Also, if it was not loose we need to repack
-        * without it.
-        */
-       ret |= repack_without_ref(lock->ref_name);
-
-       unlink_or_warn(git_path("logs/%s", lock->ref_name));
-       clear_loose_ref_cache(&ref_cache);
-       unlock_ref(lock);
-       return ret;
+       }
+       ref_transaction_free(transaction);
+       strbuf_release(&err);
+       return 0;
 }
 
 /*
@@ -3332,43 +3336,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
        return retval;
 }
 
-static struct ref_lock *update_ref_lock(const char *refname,
-                                       const unsigned char *oldval,
-                                       int flags, int *type_p,
-                                       enum action_on_err onerr)
-{
-       struct ref_lock *lock;
-       lock = lock_any_ref_for_update(refname, oldval, flags, type_p);
-       if (!lock) {
-               const char *str = "Cannot lock the ref '%s'.";
-               switch (onerr) {
-               case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-               case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-               case UPDATE_REFS_QUIET_ON_ERR: break;
-               }
-       }
-       return lock;
-}
-
-static int update_ref_write(const char *action, const char *refname,
-                           const unsigned char *sha1, struct ref_lock *lock,
-                           struct strbuf *err, enum action_on_err onerr)
-{
-       if (write_ref_sha1(lock, sha1, action) < 0) {
-               const char *str = "Cannot update the ref '%s'.";
-               if (err)
-                       strbuf_addf(err, str, refname);
-
-               switch (onerr) {
-               case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-               case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-               case UPDATE_REFS_QUIET_ON_ERR: break;
-               }
-               return 1;
-       }
-       return 0;
-}
-
 /**
  * Information needed for a single ref update.  Set new_sha1 to the
  * new value or to zero to delete the ref.  To check the old value
@@ -3385,6 +3352,21 @@ struct ref_update {
        const char refname[FLEX_ARRAY];
 };
 
+/*
+ * Transaction states.
+ * OPEN:   The transaction is in a valid state and can accept new updates.
+ *         An OPEN transaction can be committed.
+ * CLOSED: A closed transaction is no longer active and no other operations
+ *         than free can be used on it in this state.
+ *         A transaction can either become closed by successfully committing
+ *         an active transaction or if there is a failure while building
+ *         the transaction thus rendering it failed/inactive.
+ */
+enum ref_transaction_state {
+       REF_TRANSACTION_OPEN   = 0,
+       REF_TRANSACTION_CLOSED = 1
+};
+
 /*
  * Data structure for holding a reference transaction, which can
  * consist of checks and updates to multiple references, carried out
@@ -3394,9 +3376,10 @@ struct ref_transaction {
        struct ref_update **updates;
        size_t alloc;
        size_t nr;
+       enum ref_transaction_state state;
 };
 
-struct ref_transaction *ref_transaction_begin(void)
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
        return xcalloc(1, sizeof(struct ref_transaction));
 }
@@ -3436,6 +3419,9 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       if (transaction->state != REF_TRANSACTION_OPEN)
+               die("BUG: update called for transaction that is not open");
+
        if (have_old && !old_sha1)
                die("BUG: have_old is true but old_sha1 is NULL");
 
@@ -3448,44 +3434,84 @@ int ref_transaction_update(struct ref_transaction *transaction,
        return 0;
 }
 
-void ref_transaction_create(struct ref_transaction *transaction,
-                           const char *refname,
-                           const unsigned char *new_sha1,
-                           int flags)
+int ref_transaction_create(struct ref_transaction *transaction,
+                          const char *refname,
+                          const unsigned char *new_sha1,
+                          int flags,
+                          struct strbuf *err)
 {
-       struct ref_update *update = add_update(transaction, refname);
+       struct ref_update *update;
+
+       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");
+
+       update = add_update(transaction, refname);
 
-       assert(!is_null_sha1(new_sha1));
        hashcpy(update->new_sha1, new_sha1);
        hashclr(update->old_sha1);
        update->flags = flags;
        update->have_old = 1;
+       return 0;
 }
 
-void ref_transaction_delete(struct ref_transaction *transaction,
-                           const char *refname,
-                           const unsigned char *old_sha1,
-                           int flags, int have_old)
+int ref_transaction_delete(struct ref_transaction *transaction,
+                          const char *refname,
+                          const unsigned char *old_sha1,
+                          int flags, int have_old,
+                          struct strbuf *err)
 {
-       struct ref_update *update = add_update(transaction, refname);
+       struct ref_update *update;
 
+       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);
        }
+       return 0;
 }
 
 int update_ref(const char *action, const char *refname,
               const unsigned char *sha1, const unsigned char *oldval,
               int flags, enum action_on_err onerr)
 {
-       struct ref_lock *lock;
-       lock = update_ref_lock(refname, oldval, flags, NULL, onerr);
-       if (!lock)
+       struct ref_transaction *t;
+       struct strbuf err = STRBUF_INIT;
+
+       t = ref_transaction_begin(&err);
+       if (!t ||
+           ref_transaction_update(t, refname, sha1, oldval, flags,
+                                  !!oldval, &err) ||
+           ref_transaction_commit(t, action, &err)) {
+               const char *str = "update_ref failed for ref '%s': %s";
+
+               ref_transaction_free(t);
+               switch (onerr) {
+               case UPDATE_REFS_MSG_ON_ERR:
+                       error(str, refname, err.buf);
+                       break;
+               case UPDATE_REFS_DIE_ON_ERR:
+                       die(str, refname, err.buf);
+                       break;
+               case UPDATE_REFS_QUIET_ON_ERR:
+                       break;
+               }
+               strbuf_release(&err);
                return 1;
-       return update_ref_write(action, refname, sha1, lock, NULL, onerr);
+       }
+       strbuf_release(&err);
+       ref_transaction_free(t);
+       return 0;
 }
 
 static int ref_update_compare(const void *r1, const void *r2)
@@ -3519,8 +3545,13 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        int n = transaction->nr;
        struct ref_update **updates = transaction->updates;
 
-       if (!n)
+       if (transaction->state != REF_TRANSACTION_OPEN)
+               die("BUG: commit called for transaction that is not open");
+
+       if (!n) {
+               transaction->state = REF_TRANSACTION_CLOSED;
                return 0;
+       }
 
        /* Allocate work space */
        delnames = xmalloc(sizeof(*delnames) * n);
@@ -3535,12 +3566,12 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        for (i = 0; i < n; i++) {
                struct ref_update *update = updates[i];
 
-               update->lock = update_ref_lock(update->refname,
-                                              (update->have_old ?
-                                               update->old_sha1 : NULL),
-                                              update->flags,
-                                              &update->type,
-                                              UPDATE_REFS_QUIET_ON_ERR);
+               update->lock = lock_any_ref_for_update(update->refname,
+                                                      (update->have_old ?
+                                                       update->old_sha1 :
+                                                       NULL),
+                                                      update->flags,
+                                                      &update->type);
                if (!update->lock) {
                        if (err)
                                strbuf_addf(err, "Cannot lock the ref '%s'.",
@@ -3555,14 +3586,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (!is_null_sha1(update->new_sha1)) {
-                       ret = update_ref_write(msg,
-                                              update->refname,
-                                              update->new_sha1,
-                                              update->lock, err,
-                                              UPDATE_REFS_QUIET_ON_ERR);
-                       update->lock = NULL; /* freed by update_ref_write */
-                       if (ret)
+                       ret = write_ref_sha1(update->lock, update->new_sha1,
+                                            msg);
+                       update->lock = NULL; /* freed by write_ref_sha1 */
+                       if (ret) {
+                               if (err)
+                                       strbuf_addf(err, "Cannot update the ref '%s'.",
+                                                   update->refname);
                                goto cleanup;
+                       }
                }
        }
 
@@ -3571,8 +3603,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (update->lock) {
-                       delnames[delnum++] = update->lock->ref_name;
                        ret |= delete_ref_loose(update->lock, update->type);
+                       if (!(update->flags & REF_ISPRUNING))
+                               delnames[delnum++] = update->lock->ref_name;
                }
        }
 
@@ -3582,6 +3615,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        clear_loose_ref_cache(&ref_cache);
 
 cleanup:
+       transaction->state = REF_TRANSACTION_CLOSED;
+
        for (i = 0; i < n; i++)
                if (updates[i]->lock)
                        unlock_ref(updates[i]->lock);
diff --git a/refs.h b/refs.h
index ec46acdde7b67d3531a4c0e18d33901d2a4f307a..68c57701646f05a44dd0da95d981787653ae032d 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -10,6 +10,38 @@ struct ref_lock {
        int force_write;
 };
 
+/*
+ * A ref_transaction represents a collection of ref updates
+ * that should succeed or fail together.
+ *
+ * Calling sequence
+ * ----------------
+ * - Allocate and initialize a `struct ref_transaction` by calling
+ *   `ref_transaction_begin()`.
+ *
+ * - List intended ref updates by calling functions like
+ *   `ref_transaction_update()` and `ref_transaction_create()`.
+ *
+ * - Call `ref_transaction_commit()` to execute the transaction.
+ *   If this succeeds, the ref updates will have taken place and
+ *   the transaction cannot be rolled back.
+ *
+ * - At any time call `ref_transaction_free()` to discard the
+ *   transaction and free associated resources.  In particular,
+ *   this rolls back the transaction if it has not been
+ *   successfully committed.
+ *
+ * Error handling
+ * --------------
+ *
+ * On error, transaction functions append a message about what
+ * went wrong to the 'err' argument.  The message mentions what
+ * ref was being updated (if any) when the error occurred so it
+ * can be passed to 'die' or 'error' as-is.
+ *
+ * The message is appended to err without first clearing err.
+ * err will not be '\n' terminated.
+ */
 struct ref_transaction;
 
 /*
@@ -141,14 +173,17 @@ extern int is_branch(const char *refname);
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
 /*
- * Locks a "refs/" ref returning the lock on success and NULL on failure.
- * On failure errno is set to something meaningful.
+ * Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
+ * ref_transaction_create(), etc.
+ * REF_NODEREF: act on the ref directly, instead of dereferencing
+ *              symbolic references.
+ *
+ * Flags >= 0x100 are reserved for internal use.
  */
-extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
-
-/** Locks any ref (for 'HEAD' type refs). */
 #define REF_NODEREF    0x01
-/* errno is set to something meaningful on failure */
+/*
+ * This function sets errno to something meaningful on failure.
+ */
 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
                                                const unsigned char *old_sha1,
                                                int flags, int *type_p);
@@ -232,7 +267,7 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
-struct ref_transaction *ref_transaction_begin(void);
+struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
  * The following functions add a reference check or update to a
@@ -250,7 +285,7 @@ struct ref_transaction *ref_transaction_begin(void);
  * it must not have existed beforehand.
  * Function returns 0 on success and non-zero on failure. A failure to update
  * means that the transaction as a whole has failed and will need to be
- * rolled back. On failure the err buffer will be updated.
+ * rolled back.
  */
 int ref_transaction_update(struct ref_transaction *transaction,
                           const char *refname,
@@ -264,28 +299,34 @@ int ref_transaction_update(struct ref_transaction *transaction,
  * that the reference should have after the update; it must not be the
  * null SHA-1.  It is verified that the reference does not exist
  * already.
+ * Function returns 0 on success and non-zero on failure. A failure to create
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_create(struct ref_transaction *transaction,
-                           const char *refname,
-                           const unsigned char *new_sha1,
-                           int flags);
+int ref_transaction_create(struct ref_transaction *transaction,
+                          const char *refname,
+                          const unsigned char *new_sha1,
+                          int flags,
+                          struct strbuf *err);
 
 /*
  * Add a reference deletion to transaction.  If have_old is true, then
  * old_sha1 holds the value that the reference should have had before
  * the update (which must not be the null SHA-1).
+ * Function returns 0 on success and non-zero on failure. A failure to delete
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_delete(struct ref_transaction *transaction,
-                           const char *refname,
-                           const unsigned char *old_sha1,
-                           int flags, int have_old);
+int ref_transaction_delete(struct ref_transaction *transaction,
+                          const char *refname,
+                          const unsigned char *old_sha1,
+                          int flags, int have_old,
+                          struct strbuf *err);
 
 /*
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
- * If err is non-NULL we will add an error string to it to explain why
- * the transaction failed. The string does not end in newline.
  */
 int ref_transaction_commit(struct ref_transaction *transaction,
                           const char *msg, struct strbuf *err);
index 3c060e054720b7b17f9a868cabb1a0ef62aa1b50..5e8a207474bc6971a0de4f9ff6160a5681ac7b6d 100644 (file)
@@ -237,23 +237,33 @@ static int error_dirty_index(struct replay_opts *opts)
 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
                        int unborn, struct replay_opts *opts)
 {
-       struct ref_lock *ref_lock;
+       struct ref_transaction *transaction;
        struct strbuf sb = STRBUF_INIT;
-       int ret;
+       struct strbuf err = STRBUF_INIT;
 
        read_cache();
        if (checkout_fast_forward(from, to, 1))
                exit(128); /* the callee should have complained already */
-       ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
-                                          0, NULL);
-       if (!ref_lock)
-               return error(_("Failed to lock HEAD during fast_forward_to"));
 
        strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
-       ret = write_ref_sha1(ref_lock, to, sb.buf);
+
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_update(transaction, "HEAD",
+                                  to, unborn ? null_sha1 : from,
+                                  0, 1, &err) ||
+           ref_transaction_commit(transaction, sb.buf, &err)) {
+               ref_transaction_free(transaction);
+               error("%s", err.buf);
+               strbuf_release(&sb);
+               strbuf_release(&err);
+               return -1;
+       }
 
        strbuf_release(&sb);
-       return ret;
+       strbuf_release(&err);
+       ref_transaction_free(transaction);
+       return 0;
 }
 
 static int do_recursive_merge(struct commit *base, struct commit *next,
index 014826464e07c93374868c61673cfe308961dfb7..b929dcc6c043cc69b07846c16fb8aeb021aa3ae3 100644 (file)
--- a/walker.c
+++ b/walker.c
@@ -251,64 +251,73 @@ void walker_targets_free(int targets, char **target, const char **write_ref)
 int walker_fetch(struct walker *walker, int targets, char **target,
                 const char **write_ref, const char *write_ref_log_details)
 {
-       struct ref_lock **lock = xcalloc(targets, sizeof(struct ref_lock *));
+       struct strbuf refname = STRBUF_INIT;
+       struct strbuf err = STRBUF_INIT;
+       struct ref_transaction *transaction = NULL;
        unsigned char *sha1 = xmalloc(targets * 20);
-       const char *msg;
-       char *to_free = NULL;
-       int ret;
-       int i;
+       char *msg = NULL;
+       int i, ret = -1;
 
        save_commit_buffer = 0;
 
-       for (i = 0; i < targets; i++) {
-               if (!write_ref || !write_ref[i])
-                       continue;
-
-               lock[i] = lock_ref_sha1(write_ref[i], NULL);
-               if (!lock[i]) {
-                       error("Can't lock ref %s", write_ref[i]);
-                       goto unlock_and_fail;
+       if (write_ref) {
+               transaction = ref_transaction_begin(&err);
+               if (!transaction) {
+                       error("%s", err.buf);
+                       goto done;
                }
        }
-
        if (!walker->get_recover)
                for_each_ref(mark_complete, NULL);
 
        for (i = 0; i < targets; i++) {
                if (interpret_target(walker, target[i], &sha1[20 * i])) {
                        error("Could not interpret response from server '%s' as something to pull", target[i]);
-                       goto unlock_and_fail;
+                       goto done;
                }
                if (process(walker, lookup_unknown_object(&sha1[20 * i])))
-                       goto unlock_and_fail;
+                       goto done;
        }
 
        if (loop(walker))
-               goto unlock_and_fail;
-
-       if (write_ref_log_details)
-               msg = to_free = xstrfmt("fetch from %s", write_ref_log_details);
-       else
-               msg = "fetch (unknown)";
+               goto done;
+       if (!write_ref) {
+               ret = 0;
+               goto done;
+       }
+       if (write_ref_log_details) {
+               msg = xstrfmt("fetch from %s", write_ref_log_details);
+       } else {
+               msg = NULL;
+       }
        for (i = 0; i < targets; i++) {
-               if (!write_ref || !write_ref[i])
+               if (!write_ref[i])
                        continue;
-               ret = write_ref_sha1(lock[i], &sha1[20 * i], msg);
-               lock[i] = NULL;
-               if (ret)
-                       goto unlock_and_fail;
+               strbuf_reset(&refname);
+               strbuf_addf(&refname, "refs/%s", write_ref[i]);
+               if (ref_transaction_update(transaction, refname.buf,
+                                          &sha1[20 * i], NULL, 0, 0,
+                                          &err)) {
+                       error("%s", err.buf);
+                       goto done;
+               }
+       }
+       if (ref_transaction_commit(transaction,
+                                  msg ? msg : "fetch (unknown)",
+                                  &err)) {
+               error("%s", err.buf);
+               goto done;
        }
-       free(to_free);
-
-       return 0;
 
-unlock_and_fail:
-       for (i = 0; i < targets; i++)
-               if (lock[i])
-                       unlock_ref(lock[i]);
-       free(to_free);
+       ret = 0;
 
-       return -1;
+done:
+       ref_transaction_free(transaction);
+       free(msg);
+       free(sha1);
+       strbuf_release(&err);
+       strbuf_release(&refname);
+       return ret;
 }
 
 void walker_free(struct walker *walker)