Merge pull request #5570 from libgit2/pks/refdb-refactorings refdb: a set of preliminary refactorings for the reftable backend
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diff --git a/src/refdb.c b/src/refdb.c
index fbbf519..fb86d5c 100644
--- a/src/refdb.c
+++ b/src/refdb.c
@@ -17,6 +17,9 @@
#include "reflog.h"
#include "posix.h"
+#define DEFAULT_NESTING_LEVEL 5
+#define MAX_NESTING_LEVEL 10
+
int git_refdb_new(git_refdb **out, git_repository *repo)
{
git_refdb *db;
@@ -134,6 +137,59 @@ int git_refdb_lookup(git_reference **out, git_refdb *db, const char *ref_name)
return 0;
}
+int git_refdb_resolve(
+ git_reference **out,
+ git_refdb *db,
+ const char *ref_name,
+ int max_nesting)
+{
+ git_reference *ref = NULL;
+ int error = 0, nesting;
+
+ *out = NULL;
+
+ if (max_nesting > MAX_NESTING_LEVEL)
+ max_nesting = MAX_NESTING_LEVEL;
+ else if (max_nesting < 0)
+ max_nesting = DEFAULT_NESTING_LEVEL;
+
+ if ((error = git_refdb_lookup(&ref, db, ref_name)) < 0)
+ goto out;
+
+ for (nesting = 0; nesting < max_nesting; nesting++) {
+ git_reference *resolved;
+
+ if (ref->type == GIT_REFERENCE_DIRECT)
+ break;
+
+ if ((error = git_refdb_lookup(&resolved, db, git_reference_symbolic_target(ref))) < 0) {
+ /* If we found a symbolic reference with a nonexistent target, return it. */
+ if (error == GIT_ENOTFOUND) {
+ error = 0;
+ *out = ref;
+ ref = NULL;
+ }
+ goto out;
+ }
+
+ git_reference_free(ref);
+ ref = resolved;
+ }
+
+ if (ref->type != GIT_REFERENCE_DIRECT && max_nesting != 0) {
+ git_error_set(GIT_ERROR_REFERENCE,
+ "cannot resolve reference (>%u levels deep)", max_nesting);
+ error = -1;
+ goto out;
+ }
+
+ *out = ref;
+ ref = NULL;
+out:
+ git_reference_free(ref);
+ return error;
+}
+
int git_refdb_iterator(git_reference_iterator **out, git_refdb *db, const char *glob)
{
int error;
@@ -231,6 +287,85 @@ int git_refdb_reflog_read(git_reflog **out, git_refdb *db, const char *name)
return 0;
}
+int git_refdb_should_write_reflog(int *out, git_refdb *db, const git_reference *ref)
+{
+ int error, logall;
+
+ error = git_repository__configmap_lookup(&logall, db->repo, GIT_CONFIGMAP_LOGALLREFUPDATES);
+ if (error < 0)
+ return error;
+
+ /* Defaults to the opposite of the repo being bare */
+ if (logall == GIT_LOGALLREFUPDATES_UNSET)
+ logall = !git_repository_is_bare(db->repo);
+
+ *out = 0;
+ switch (logall) {
+ case GIT_LOGALLREFUPDATES_FALSE:
+ *out = 0;
+ break;
+
+ case GIT_LOGALLREFUPDATES_TRUE:
+ /* Only write if it already has a log,
+ * or if it's under heads/, remotes/ or notes/
+ */
+ *out = git_refdb_has_log(db, ref->name) ||
+ !git__prefixcmp(ref->name, GIT_REFS_HEADS_DIR) ||
+ !git__strcmp(ref->name, GIT_HEAD_FILE) ||
+ !git__prefixcmp(ref->name, GIT_REFS_REMOTES_DIR) ||
+ !git__prefixcmp(ref->name, GIT_REFS_NOTES_DIR);
+ break;
+
+ case GIT_LOGALLREFUPDATES_ALWAYS:
+ *out = 1;
+ break;
+ }
+
+ return 0;
+}
+
+int git_refdb_should_write_head_reflog(int *out, git_refdb *db, const git_reference *ref)
+{
+ git_reference *head = NULL, *resolved = NULL;
+ const char *name;
+ int error;
+
+ *out = 0;
+
+ if (ref->type == GIT_REFERENCE_SYMBOLIC) {
+ error = 0;
+ goto out;
+ }
+
+ if ((error = git_refdb_lookup(&head, db, GIT_HEAD_FILE)) < 0)
+ goto out;
+
+ if (git_reference_type(head) == GIT_REFERENCE_DIRECT)
+ goto out;
+
+ /* Go down the symref chain until we find the branch */
+ if ((error = git_refdb_resolve(&resolved, db, git_reference_symbolic_target(head), -1)) < 0) {
+ if (error != GIT_ENOTFOUND)
+ goto out;
+ error = 0;
+ name = git_reference_symbolic_target(head);
+ } else if (git_reference_type(resolved) == GIT_REFERENCE_SYMBOLIC) {
+ name = git_reference_symbolic_target(resolved);
+ } else {
+ name = git_reference_name(resolved);
+ }
+
+ if (strcmp(name, ref->name))
+ goto out;
+
+ *out = 1;
+
+out:
+ git_reference_free(resolved);
+ git_reference_free(head);
+ return error;
+}
+
int git_refdb_has_log(git_refdb *db, const char *refname)
{
assert(db && refname);
diff --git a/src/refdb.h b/src/refdb.h
index 2d4ec75..84e19b1 100644
--- a/src/refdb.h
+++ b/src/refdb.h
@@ -30,6 +30,31 @@ int git_refdb_lookup(
git_refdb *refdb,
const char *ref_name);
+/**
+ * Resolve the reference by following symbolic references.
+ *
+ * Given a reference name, this function will follow any symbolic references up
+ * to `max_nesting` deep and return the resolved direct reference. If any of
+ * the intermediate symbolic references points to a non-existing reference,
+ * then that symbolic reference is returned instead with an error code of `0`.
+ * If the given reference is a direct reference already, it is returned
+ * directly.
+ *
+ * If `max_nesting` is `0`, the reference will not be resolved. If it's
+ * negative, it will be set to the default resolve depth which is `5`.
+ *
+ * @param out Pointer to store the result in.
+ * @param db The refdb to use for resolving the reference.
+ * @param ref_name The reference name to lookup and resolve.
+ * @param max_nesting The maximum nesting depth.
+ * @return `0` on success, a negative error code otherwise.
+ */
+int git_refdb_resolve(
+ git_reference **out,
+ git_refdb *db,
+ const char *ref_name,
+ int max_nesting);
+
int git_refdb_rename(
git_reference **out,
git_refdb *db,
@@ -50,6 +75,50 @@ int git_refdb_delete(git_refdb *refdb, const char *ref_name, const git_oid *old_
int git_refdb_reflog_read(git_reflog **out, git_refdb *db, const char *name);
int git_refdb_reflog_write(git_reflog *reflog);
+/**
+ * Determine whether a reflog entry should be created for the given reference.
+ *
+ * Whether or not writing to a reference should create a reflog entry is
+ * dependent on a number of things. Most importantly, there's the
+ * "core.logAllRefUpdates" setting that controls in which situations a
+ * reference should get a corresponding reflog entry. The following values for
+ * it are understood:
+ *
+ * - "false": Do not log reference updates.
+ *
+ * - "true": Log normal reference updates. This will write entries for
+ * references in "refs/heads", "refs/remotes", "refs/notes" and
+ * "HEAD" or if the reference already has a log entry.
+ *
+ * - "always": Always create a reflog entry.
+ *
+ * If unset, the value will default to "true" for non-bare repositories and
+ * "false" for bare ones.
+ *
+ * @param out pointer to which the result will be written, `1` means a reflog
+ * entry should be written, `0` means none should be written.
+ * @param db The refdb to decide this for.
+ * @param ref The reference one wants to check.
+ * @return `0` on success, a negative error code otherwise.
+ */
+int git_refdb_should_write_reflog(int *out, git_refdb *db, const git_reference *ref);
+
+/**
+ * Determine whether a reflog entry should be created for HEAD if creating one
+ * for the given reference
+ *
+ * In case the given reference is being pointed to by HEAD, then creating a
+ * reflog entry for this reference also requires us to create a corresponding
+ * reflog entry for HEAD. This function can be used to determine that scenario.
+ *
+ * @param out pointer to which the result will be written, `1` means a reflog
+ * entry should be written, `0` means none should be written.
+ * @param db The refdb to decide this for.
+ * @param ref The reference one wants to check.
+ * @return `0` on success, a negative error code otherwise.
+ */
+int git_refdb_should_write_head_reflog(int *out, git_refdb *db, const git_reference *ref);
+
int git_refdb_has_log(git_refdb *db, const char *refname);
int git_refdb_ensure_log(git_refdb *refdb, const char *refname);
diff --git a/src/refdb_fs.c b/src/refdb_fs.c
index 28ea474..7e04819 100644
--- a/src/refdb_fs.c
+++ b/src/refdb_fs.c
@@ -1128,44 +1128,6 @@ cleanup:
}
static int reflog_append(refdb_fs_backend *backend, const git_reference *ref, const git_oid *old, const git_oid *new, const git_signature *author, const char *message);
-static int has_reflog(git_repository *repo, const char *name);
-
-static int should_write_reflog(int *write, git_repository *repo, const char *name)
-{
- int error, logall;
-
- error = git_repository__configmap_lookup(&logall, repo, GIT_CONFIGMAP_LOGALLREFUPDATES);
- if (error < 0)
- return error;
-
- /* Defaults to the opposite of the repo being bare */
- if (logall == GIT_LOGALLREFUPDATES_UNSET)
- logall = !git_repository_is_bare(repo);
-
- *write = 0;
- switch (logall) {
- case GIT_LOGALLREFUPDATES_FALSE:
- *write = 0;
- break;
-
- case GIT_LOGALLREFUPDATES_TRUE:
- /* Only write if it already has a log,
- * or if it's under heads/, remotes/ or notes/
- */
- *write = has_reflog(repo, name) ||
- !git__prefixcmp(name, GIT_REFS_HEADS_DIR) ||
- !git__strcmp(name, GIT_HEAD_FILE) ||
- !git__prefixcmp(name, GIT_REFS_REMOTES_DIR) ||
- !git__prefixcmp(name, GIT_REFS_NOTES_DIR);
- break;
-
- case GIT_LOGALLREFUPDATES_ALWAYS:
- *write = 1;
- break;
- }
-
- return 0;
-}
static int cmp_old_ref(int *cmp, git_refdb_backend *backend, const char *name,
const git_oid *old_id, const char *old_target)
@@ -1219,54 +1181,28 @@ out:
*/
static int maybe_append_head(refdb_fs_backend *backend, const git_reference *ref, const git_signature *who, const char *message)
{
- int error;
+ git_reference *head = NULL;
+ git_refdb *refdb = NULL;
+ int error, write_reflog;
git_oid old_id;
- git_reference *tmp = NULL, *head = NULL, *peeled = NULL;
- const char *name;
- if (ref->type == GIT_REFERENCE_SYMBOLIC)
- return 0;
+ if ((error = git_repository_refdb(&refdb, backend->repo)) < 0 ||
+ (error = git_refdb_should_write_head_reflog(&write_reflog, refdb, ref)) < 0)
+ goto out;
+ if (!write_reflog)
+ goto out;
/* if we can't resolve, we use {0}*40 as old id */
if (git_reference_name_to_id(&old_id, backend->repo, ref->name) < 0)
memset(&old_id, 0, sizeof(old_id));
- if ((error = git_reference_lookup(&head, backend->repo, GIT_HEAD_FILE)) < 0)
- return error;
-
- if (git_reference_type(head) == GIT_REFERENCE_DIRECT)
- goto cleanup;
-
- if ((error = git_reference_lookup(&tmp, backend->repo, GIT_HEAD_FILE)) < 0)
- goto cleanup;
-
- /* Go down the symref chain until we find the branch */
- while (git_reference_type(tmp) == GIT_REFERENCE_SYMBOLIC) {
- error = git_reference_lookup(&peeled, backend->repo, git_reference_symbolic_target(tmp));
- if (error < 0)
- break;
-
- git_reference_free(tmp);
- tmp = peeled;
- }
-
- if (error == GIT_ENOTFOUND) {
- error = 0;
- name = git_reference_symbolic_target(tmp);
- } else if (error < 0) {
- goto cleanup;
- } else {
- name = git_reference_name(tmp);
- }
-
- if (strcmp(name, ref->name))
- goto cleanup;
-
- error = reflog_append(backend, head, &old_id, git_reference_target(ref), who, message);
+ if ((error = git_reference_lookup(&head, backend->repo, GIT_HEAD_FILE)) < 0 ||
+ (error = reflog_append(backend, head, &old_id, git_reference_target(ref), who, message)) < 0)
+ goto out;
-cleanup:
- git_reference_free(tmp);
+out:
git_reference_free(head);
+ git_refdb_free(refdb);
return error;
}
@@ -1335,7 +1271,10 @@ static int refdb_fs_backend__write_tail(
}
if (update_reflog) {
- if ((error = should_write_reflog(&should_write, backend->repo, ref->name)) < 0)
+ git_refdb *refdb;
+
+ if ((error = git_repository_refdb__weakptr(&refdb, backend->repo)) < 0 ||
+ (error = git_refdb_should_write_reflog(&should_write, refdb, ref)) < 0)
goto on_error;
if (should_write) {
diff --git a/src/refs.c b/src/refs.c
index c5d69c1..9ef1677 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -27,9 +27,6 @@
bool git_reference__enable_symbolic_ref_target_validation = true;
-#define DEFAULT_NESTING_LEVEL 5
-#define MAX_NESTING_LEVEL 10
-
enum {
GIT_PACKREF_HAS_PEEL = 1,
GIT_PACKREF_WAS_LOOSE = 2
@@ -214,52 +211,29 @@ int git_reference_lookup_resolved(
const char *name,
int max_nesting)
{
- git_refname_t scan_name;
- git_reference_t scan_type;
- int error = 0, nesting;
- git_reference *ref = NULL;
+ git_refname_t normalized;
git_refdb *refdb;
+ int error = 0;
assert(ref_out && repo && name);
- *ref_out = NULL;
-
- if (max_nesting > MAX_NESTING_LEVEL)
- max_nesting = MAX_NESTING_LEVEL;
- else if (max_nesting < 0)
- max_nesting = DEFAULT_NESTING_LEVEL;
-
- scan_type = GIT_REFERENCE_SYMBOLIC;
-
- if ((error = reference_normalize_for_repo(scan_name, repo, name, true)) < 0)
+ if ((error = reference_normalize_for_repo(normalized, repo, name, true)) < 0 ||
+ (error = git_repository_refdb__weakptr(&refdb, repo)) < 0 ||
+ (error = git_refdb_resolve(ref_out, refdb, normalized, max_nesting)) < 0)
return error;
- if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
- return error;
-
- for (nesting = max_nesting;
- nesting >= 0 && scan_type == GIT_REFERENCE_SYMBOLIC;
- nesting--)
- {
- if (nesting != max_nesting) {
- strncpy(scan_name, ref->target.symbolic, sizeof(scan_name));
- git_reference_free(ref);
- }
-
- if ((error = git_refdb_lookup(&ref, refdb, scan_name)) < 0)
- return error;
-
- scan_type = ref->type;
- }
-
- if (scan_type != GIT_REFERENCE_DIRECT && max_nesting != 0) {
- git_error_set(GIT_ERROR_REFERENCE,
- "cannot resolve reference (>%u levels deep)", max_nesting);
- git_reference_free(ref);
- return -1;
+ /*
+ * The resolved reference may be a symbolic reference in case its
+ * target doesn't exist. If the user asked us to resolve (e.g.
+ * `max_nesting != 0`), then we need to return an error in case we got
+ * a symbolic reference back.
+ */
+ if (max_nesting && git_reference_type(*ref_out) == GIT_REFERENCE_SYMBOLIC) {
+ git_reference_free(*ref_out);
+ *ref_out = NULL;
+ return GIT_ENOTFOUND;
}
- *ref_out = ref;
return 0;
}
@@ -1154,40 +1128,6 @@ int git_reference_cmp(
return git_oid__cmp(&ref1->target.oid, &ref2->target.oid);
}
-/**
- * Get the end of a chain of references. If the final one is not
- * found, we return the reference just before that.
- */
-static int get_terminal(git_reference **out, git_repository *repo, const char *ref_name, int nesting)
-{
- git_reference *ref;
- int error = 0;
-
- if (nesting > MAX_NESTING_LEVEL) {
- git_error_set(GIT_ERROR_REFERENCE, "reference chain too deep (%d)", nesting);
- return GIT_ENOTFOUND;
- }
-
- /* set to NULL to let the caller know that they're at the end of the chain */
- if ((error = git_reference_lookup(&ref, repo, ref_name)) < 0) {
- *out = NULL;
- return error;
- }
-
- if (git_reference_type(ref) == GIT_REFERENCE_DIRECT) {
- *out = ref;
- error = 0;
- } else {
- error = get_terminal(out, repo, git_reference_symbolic_target(ref), nesting + 1);
- if (error == GIT_ENOTFOUND && !*out)
- *out = ref;
- else
- git_reference_free(ref);
- }
-
- return error;
-}
-
/*
* Starting with the reference given by `ref_name`, follows symbolic
* references until a direct reference is found and updated the OID
@@ -1202,31 +1142,37 @@ int git_reference__update_terminal(
{
git_reference *ref = NULL, *ref2 = NULL;
git_signature *who = NULL;
+ git_refdb *refdb = NULL;
const git_signature *to_use;
int error = 0;
if (!sig && (error = git_reference__log_signature(&who, repo)) < 0)
- return error;
+ goto out;
to_use = sig ? sig : who;
- error = get_terminal(&ref, repo, ref_name, 0);
- /* found a dangling symref */
- if (error == GIT_ENOTFOUND && ref) {
- assert(git_reference_type(ref) == GIT_REFERENCE_SYMBOLIC);
- git_error_clear();
+ if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
+ goto out;
+
+ if ((error = git_refdb_resolve(&ref, refdb, ref_name, -1)) < 0) {
+ if (error == GIT_ENOTFOUND) {
+ git_error_clear();
+ error = reference__create(&ref2, repo, ref_name, oid, NULL, 0, to_use,
+ log_message, NULL, NULL);
+ }
+ goto out;
+ }
+
+ /* In case the resolved reference is symbolic, then it's a dangling symref. */
+ if (git_reference_type(ref) == GIT_REFERENCE_SYMBOLIC) {
error = reference__create(&ref2, repo, ref->target.symbolic, oid, NULL, 0, to_use,
log_message, NULL, NULL);
- } else if (error == GIT_ENOTFOUND) {
- git_error_clear();
- error = reference__create(&ref2, repo, ref_name, oid, NULL, 0, to_use,
- log_message, NULL, NULL);
- } else if (error == 0) {
- assert(git_reference_type(ref) == GIT_REFERENCE_DIRECT);
+ } else {
error = reference__create(&ref2, repo, ref->name, oid, NULL, 1, to_use,
log_message, &ref->target.oid, NULL);
}
+out:
git_reference_free(ref2);
git_reference_free(ref);
git_signature_free(who);
diff --git a/tests/refs/reflog/messages.c b/tests/refs/reflog/messages.c
index 43f59a8..53b8c6f 100644
--- a/tests/refs/reflog/messages.c
+++ b/tests/refs/reflog/messages.c
@@ -24,11 +24,8 @@ void test_refs_reflog_messages__cleanup(void)
void test_refs_reflog_messages__setting_head_updates_reflog(void)
{
git_object *tag;
- git_signature *sig;
git_annotated_commit *annotated;
- cl_git_pass(git_signature_now(&sig, "me", "foo@example.com"));
-
cl_git_pass(git_repository_set_head(g_repo, "refs/heads/haacked")); /* 4 */
cl_git_pass(git_repository_set_head(g_repo, "refs/heads/unborn"));
cl_git_pass(git_revparse_single(&tag, g_repo, "tags/test"));
@@ -68,7 +65,6 @@ void test_refs_reflog_messages__setting_head_updates_reflog(void)
git_annotated_commit_free(annotated);
git_object_free(tag);
- git_signature_free(sig);
}
void test_refs_reflog_messages__setting_head_to_same_target_ignores_reflog(void)
@@ -87,12 +83,9 @@ void test_refs_reflog_messages__setting_head_to_same_target_ignores_reflog(void)
void test_refs_reflog_messages__detaching_writes_reflog(void)
{
- git_signature *sig;
git_oid id;
const char *msg;
- cl_git_pass(git_signature_now(&sig, "me", "foo@example.com"));
-
msg = "checkout: moving from master to e90810b8df3e80c413d903f631643c716887138d";
git_oid_fromstr(&id, "e90810b8df3e80c413d903f631643c716887138d");
cl_git_pass(git_repository_set_head_detached(g_repo, &id));
@@ -107,8 +100,6 @@ void test_refs_reflog_messages__detaching_writes_reflog(void)
"e90810b8df3e80c413d903f631643c716887138d",
"258f0e2a959a364e40ed6603d5d44fbb24765b10",
NULL, msg);
-
- git_signature_free(sig);
}
void test_refs_reflog_messages__orphan_branch_does_not_count(void)