git/refs.h

#ifndef REFS_H
#define REFS_H

#include "commit.h"

struct object_id;
struct ref_store;
struct repository;
struct strbuf;
struct string_list;
struct string_list_item;
struct worktree;

/*
 * Resolve a reference, recursively following symbolic refererences.
 *
 * Return the name of the non-symbolic reference that ultimately pointed
 * at the resolved object name.  The return value, if not NULL, is a
 * pointer into either a static buffer or the input ref.
 *
 * If oid is non-NULL, store the referred-to object's name in it.
 *
 * If the reference cannot be resolved to an object, the behavior
 * depends on the RESOLVE_REF_READING flag:
 *
 * - If RESOLVE_REF_READING is set, return NULL.
 *
 * - If RESOLVE_REF_READING is not set, clear oid and return the name of
 *   the last reference name in the chain, which will either be a non-symbolic
 *   reference or an undefined reference.  If this is a prelude to
 *   "writing" to the ref, the return value is the name of the ref
 *   that will actually be created or changed.
 *
 * If the RESOLVE_REF_NO_RECURSE flag is passed, only resolves one
 * level of symbolic reference.  The value stored in oid for a symbolic
 * reference will always be null_oid in this case, and the return
 * value is the reference that the symref refers to directly.
 *
 * If flags is non-NULL, set the value that it points to the
 * combination of REF_ISPACKED (if the reference was found among the
 * packed references), REF_ISSYMREF (if the initial reference was a
 * symbolic reference), REF_BAD_NAME (if the reference name is ill
 * formed --- see RESOLVE_REF_ALLOW_BAD_NAME below), and REF_ISBROKEN
 * (if the ref is malformed or has a bad name). See refs.h for more detail
 * on each flag.
 *
 * If ref is not a properly-formatted, normalized reference, return
 * NULL.  If more than MAXDEPTH recursive symbolic lookups are needed,
 * give up and return NULL.
 *
 * RESOLVE_REF_ALLOW_BAD_NAME allows resolving refs even when their
 * name is invalid according to git-check-ref-format(1).  If the name
 * is bad then the value stored in oid will be null_oid and the two
 * flags REF_ISBROKEN and REF_BAD_NAME will be set.
 *
 * Even with RESOLVE_REF_ALLOW_BAD_NAME, names that escape the refs/
 * directory and do not consist of all caps and underscores cannot be
 * resolved. The function returns NULL for such ref names.
 * Caps and underscores refers to the special refs, such as HEAD,
 * FETCH_HEAD and friends, that all live outside of the refs/ directory.
 */
#define RESOLVE_REF_READING 0x01
#define RESOLVE_REF_NO_RECURSE 0x02
#define RESOLVE_REF_ALLOW_BAD_NAME 0x04

struct pack_refs_opts {
	unsigned int flags;
	struct ref_exclusions *exclusions;
	struct string_list *includes;
};

const char *refs_resolve_ref_unsafe(struct ref_store *refs,
				    const char *refname,
				    int resolve_flags,
				    struct object_id *oid,
				    int *flags);

const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
			       struct object_id *oid, int *flags);

char *refs_resolve_refdup(struct ref_store *refs,
			  const char *refname, int resolve_flags,
			  struct object_id *oid, int *flags);
char *resolve_refdup(const char *refname, int resolve_flags,
		     struct object_id *oid, int *flags);

int read_ref_full(const char *refname, int resolve_flags,
		  struct object_id *oid, int *flags);
int read_ref(const char *refname, struct object_id *oid);

int refs_read_symbolic_ref(struct ref_store *ref_store, const char *refname,
			   struct strbuf *referent);

/*
 * Return 0 if a reference named refname could be created without
 * conflicting with the name of an existing reference. Otherwise,
 * return a negative value and write an explanation to err. If extras
 * is non-NULL, it is a list of additional refnames with which refname
 * is not allowed to conflict. If skip is non-NULL, ignore potential
 * conflicts with refs in skip (e.g., because they are scheduled for
 * deletion in the same operation). Behavior is undefined if the same
 * name is listed in both extras and skip.
 *
 * Two reference names conflict if one of them exactly matches the
 * leading components of the other; e.g., "foo/bar" conflicts with
 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 * "foo/barbados".
 *
 * extras and skip must be sorted.
 */

int refs_verify_refname_available(struct ref_store *refs,
				  const char *refname,
				  const struct string_list *extras,
				  const struct string_list *skip,
				  struct strbuf *err);

int refs_ref_exists(struct ref_store *refs, const char *refname);

int ref_exists(const char *refname);

int should_autocreate_reflog(const char *refname);

int is_branch(const char *refname);

int refs_init_db(struct strbuf *err);

/*
 * Return the peeled value of the oid currently being iterated via
 * for_each_ref(), etc. This is equivalent to calling:
 *
 *   peel_object(oid, &peeled);
 *
 * with the "oid" value given to the each_ref_fn callback, except
 * that some ref storage may be able to answer the query without
 * actually loading the object in memory.
 */
int peel_iterated_oid(const struct object_id *base, struct object_id *peeled);

/**
 * Resolve refname in the nested "gitlink" repository in the specified
 * submodule (which must be non-NULL). If the resolution is
 * successful, return 0 and set oid to the name of the object;
 * otherwise, return a non-zero value.
 */
int resolve_gitlink_ref(const char *submodule, const char *refname,
			struct object_id *oid);

/*
 * Return true iff abbrev_name is a possible abbreviation for
 * full_name according to the rules defined by ref_rev_parse_rules in
 * refs.c.
 */
int refname_match(const char *abbrev_name, const char *full_name);

/*
 * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
 * the results to 'prefixes'
 */
struct strvec;
void expand_ref_prefix(struct strvec *prefixes, const char *prefix);

int expand_ref(struct repository *r, const char *str, int len, struct object_id *oid, char **ref);
int repo_dwim_ref(struct repository *r, const char *str, int len,
		  struct object_id *oid, char **ref, int nonfatal_dangling_mark);
int repo_dwim_log(struct repository *r, const char *str, int len, struct object_id *oid, char **ref);
int dwim_log(const char *str, int len, struct object_id *oid, char **ref);

/*
 * Retrieves the default branch name for newly-initialized repositories.
 *
 * The return value of `repo_default_branch_name()` is an allocated string. The
 * return value of `git_default_branch_name()` is a singleton.
 */
const char *git_default_branch_name(int quiet);
char *repo_default_branch_name(struct repository *r, int quiet);

/*
 * A ref_transaction represents a collection of reference updates that
 * should succeed or fail together.
 *
 * Calling sequence
 * ----------------
 *
 * - Allocate and initialize a `struct ref_transaction` by calling
 *   `ref_transaction_begin()`.
 *
 * - Specify the intended ref updates by calling one or more of the
 *   following functions:
 *   - `ref_transaction_update()`
 *   - `ref_transaction_create()`
 *   - `ref_transaction_delete()`
 *   - `ref_transaction_verify()`
 *
 * - Then either:
 *
 *   - Optionally call `ref_transaction_prepare()` to prepare the
 *     transaction. This locks all references, checks preconditions,
 *     etc. but doesn't finalize anything. If this step fails, the
 *     transaction has been closed and can only be freed. If this step
 *     succeeds, then `ref_transaction_commit()` is almost certain to
 *     succeed. However, you can still call `ref_transaction_abort()`
 *     if you decide not to commit the transaction after all.
 *
 *   - Call `ref_transaction_commit()` to execute the transaction,
 *     make the changes permanent, and release all locks. If you
 *     haven't already called `ref_transaction_prepare()`, then
 *     `ref_transaction_commit()` calls it for you.
 *
 *   Or
 *
 *   - Call `initial_ref_transaction_commit()` if the ref database is
 *     known to be empty and have no other writers (e.g. during
 *     clone). This is likely to be much faster than
 *     `ref_transaction_commit()`. `ref_transaction_prepare()` should
 *     *not* be called before `initial_ref_transaction_commit()`.
 *
 * - Then finally, call `ref_transaction_free()` to free the
 *   `ref_transaction` data structure.
 *
 * At any time before calling `ref_transaction_commit()`, you can call
 * `ref_transaction_abort()` to abort the transaction, rollback any
 * locks, and free any associated resources (including the
 * `ref_transaction` data structure).
 *
 * Putting it all together, a complete reference update looks like
 *
 *         struct ref_transaction *transaction;
 *         struct strbuf err = STRBUF_INIT;
 *         int ret = 0;
 *
 *         transaction = ref_store_transaction_begin(refs, &err);
 *         if (!transaction ||
 *             ref_transaction_update(...) ||
 *             ref_transaction_create(...) ||
 *             ...etc... ||
 *             ref_transaction_commit(transaction, &err)) {
 *                 error("%s", err.buf);
 *                 ret = -1;
 *         }
 *         ref_transaction_free(transaction);
 *         strbuf_release(&err);
 *         return ret;
 *
 * 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.
 *
 * Caveats
 * -------
 *
 * Note that no locks are taken, and no refs are read, until
 * `ref_transaction_prepare()` or `ref_transaction_commit()` is
 * called. So, for example, `ref_transaction_verify()` won't report a
 * verification failure until the commit is attempted.
 */
struct ref_transaction;

/*
 * Bit values set in the flags argument passed to each_ref_fn() and
 * stored in ref_iterator::flags. Other bits are for internal use
 * only:
 */

/* Reference is a symbolic reference. */
#define REF_ISSYMREF 0x01

/* Reference is a packed reference. */
#define REF_ISPACKED 0x02

/*
 * Reference cannot be resolved to an object name: dangling symbolic
 * reference (directly or indirectly), corrupt reference file,
 * reference exists but name is bad, or symbolic reference refers to
 * ill-formatted reference name.
 */
#define REF_ISBROKEN 0x04

/*
 * Reference name is not well formed.
 *
 * See git-check-ref-format(1) for the definition of well formed ref names.
 */
#define REF_BAD_NAME 0x08

/*
 * The signature for the callback function for the for_each_*()
 * functions below.  The memory pointed to by the refname and oid
 * arguments is only guaranteed to be valid for the duration of a
 * single callback invocation.
 */
typedef int each_ref_fn(const char *refname,
			const struct object_id *oid, int flags, void *cb_data);

/*
 * The same as each_ref_fn, but also with a repository argument that
 * contains the repository associated with the callback.
 */
typedef int each_repo_ref_fn(struct repository *r,
			     const char *refname,
			     const struct object_id *oid,
			     int flags,
			     void *cb_data);

/*
 * The following functions invoke the specified callback function for
 * each reference indicated.  If the function ever returns a nonzero
 * value, stop the iteration and return that value.  Please note that
 * it is not safe to modify references while an iteration is in
 * progress, unless the same callback function invocation that
 * modifies the reference also returns a nonzero value to immediately
 * stop the iteration. Returned references are sorted.
 */
int refs_head_ref(struct ref_store *refs,
		  each_ref_fn fn, void *cb_data);
int refs_for_each_ref(struct ref_store *refs,
		      each_ref_fn fn, void *cb_data);
int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
			 each_ref_fn fn, void *cb_data);
int refs_for_each_tag_ref(struct ref_store *refs,
			  each_ref_fn fn, void *cb_data);
int refs_for_each_branch_ref(struct ref_store *refs,
			     each_ref_fn fn, void *cb_data);
int refs_for_each_remote_ref(struct ref_store *refs,
			     each_ref_fn fn, void *cb_data);

/* just iterates the head ref. */
int head_ref(each_ref_fn fn, void *cb_data);

/* iterates all refs. */
int for_each_ref(each_ref_fn fn, void *cb_data);

/**
 * iterates all refs which have a defined prefix and strips that prefix from
 * the passed variable refname.
 */
int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);

/*
 * references matching any pattern in "exclude_patterns" are omitted from the
 * result set on a best-effort basis.
 */
int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
			     const char **exclude_patterns,
			     each_ref_fn fn, void *cb_data);
int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data);

/**
 * iterate all refs in "patterns" by partitioning patterns into disjoint sets
 * and iterating the longest-common prefix of each set.
 *
 * references matching any pattern in "exclude_patterns" are omitted from the
 * result set on a best-effort basis.
 *
 * callers should be prepared to ignore references that they did not ask for.
 */
int refs_for_each_fullref_in_prefixes(struct ref_store *refs,
				      const char *namespace,
				      const char **patterns,
				      const char **exclude_patterns,
				      each_ref_fn fn, void *cb_data);

/**
 * iterate refs from the respective area.
 */
int for_each_tag_ref(each_ref_fn fn, void *cb_data);
int for_each_branch_ref(each_ref_fn fn, void *cb_data);
int for_each_remote_ref(each_ref_fn fn, void *cb_data);
int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data);

/* iterates all refs that match the specified glob pattern. */
int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);

int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
			 const char *prefix, void *cb_data);

int head_ref_namespaced(each_ref_fn fn, void *cb_data);
/*
 * references matching any pattern in "exclude_patterns" are omitted from the
 * result set on a best-effort basis.
 */
int for_each_namespaced_ref(const char **exclude_patterns,
			    each_ref_fn fn, void *cb_data);

/* can be used to learn about broken ref and symref */
int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data);
int for_each_rawref(each_ref_fn fn, void *cb_data);

/*
 * Normalizes partial refs to their fully qualified form.
 * Will prepend <prefix> to the <pattern> if it doesn't start with 'refs/'.
 * <prefix> will default to 'refs/' if NULL.
 *
 * item.string will be set to the result.
 * item.util will be set to NULL if <pattern> contains glob characters, or
 * non-NULL if it doesn't.
 */
void normalize_glob_ref(struct string_list_item *item, const char *prefix,
			const char *pattern);

static inline const char *has_glob_specials(const char *pattern)
{
	return strpbrk(pattern, "?*[");
}

void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
void warn_dangling_symrefs(FILE *fp, const char *msg_fmt,
			   const struct string_list *refnames);

/*
 * Flags for controlling behaviour of pack_refs()
 * PACK_REFS_PRUNE: Prune loose refs after packing
 * PACK_REFS_ALL:   Pack _all_ refs, not just tags and already packed refs
 */
#define PACK_REFS_PRUNE 0x0001
#define PACK_REFS_ALL   0x0002

/*
 * Write a packed-refs file for the current repository.
 * flags: Combination of the above PACK_REFS_* flags.
 */
int refs_pack_refs(struct ref_store *refs, struct pack_refs_opts *opts);

/*
 * Setup reflog before using. Fill in err and return -1 on failure.
 */
int refs_create_reflog(struct ref_store *refs, const char *refname,
		       struct strbuf *err);
int safe_create_reflog(const char *refname, struct strbuf *err);

/** Reads log for the value of ref during at_time. **/
int read_ref_at(struct ref_store *refs,
		const char *refname, unsigned int flags,
		timestamp_t at_time, int cnt,
		struct object_id *oid, char **msg,
		timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt);

/** Check if a particular reflog exists */
int refs_reflog_exists(struct ref_store *refs, const char *refname);
int reflog_exists(const char *refname);

/*
 * Delete the specified reference. If old_oid is non-NULL, then
 * verify that the current value of the reference is old_oid before
 * deleting it. If old_oid is NULL, delete the reference if it
 * exists, regardless of its old value. It is an error for old_oid to
 * be null_oid. msg and flags are passed through to
 * ref_transaction_delete().
 */
int refs_delete_ref(struct ref_store *refs, const char *msg,
		    const char *refname,
		    const struct object_id *old_oid,
		    unsigned int flags);
int delete_ref(const char *msg, const char *refname,
	       const struct object_id *old_oid, unsigned int flags);

/*
 * Delete the specified references. If there are any problems, emit
 * errors but attempt to keep going (i.e., the deletes are not done in
 * an all-or-nothing transaction). msg and flags are passed through to
 * ref_transaction_delete().
 */
int refs_delete_refs(struct ref_store *refs, const char *msg,
		     struct string_list *refnames, unsigned int flags);
int delete_refs(const char *msg, struct string_list *refnames,
		unsigned int flags);

/** Delete a reflog */
int refs_delete_reflog(struct ref_store *refs, const char *refname);
int delete_reflog(const char *refname);

/*
 * Callback to process a reflog entry found by the iteration functions (see
 * below).
 *
 * The committer parameter is a single string, in the form
 * "$GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" (without double quotes).
 *
 * The timestamp parameter gives the time when entry was created as the number
 * of seconds since the UNIX epoch.
 *
 * The tz parameter gives the timezone offset for the user who created
 * the reflog entry, and its value gives a positive or negative offset
 * from UTC.  Its absolute value is formed by multiplying the hour
 * part by 100 and adding the minute part.  For example, 1 hour ahead
 * of UTC, CET == "+0100", is represented as positive one hundred (not
 * postiive sixty).
 *
 * The msg parameter is a single complete line; a reflog message given
 * to refs_delete_ref, refs_update_ref, etc. is returned to the
 * callback normalized---each run of whitespaces are squashed into a
 * single whitespace, trailing whitespace, if exists, is trimmed, and
 * then a single LF is added at the end.
 *
 * The cb_data is a caller-supplied pointer given to the iterator
 * functions.
 */
typedef int each_reflog_ent_fn(
		struct object_id *old_oid, struct object_id *new_oid,
		const char *committer, timestamp_t timestamp,
		int tz, const char *msg, void *cb_data);

/* Iterate over reflog entries in the log for `refname`. */

/* oldest entry first */
int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
			     each_reflog_ent_fn fn, void *cb_data);

/* youngest entry first */
int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
				     const char *refname,
				     each_reflog_ent_fn fn,
				     void *cb_data);

/*
 * Iterate over reflog entries in the log for `refname` in the main ref store.
 */

/* oldest entry first */
int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);

/* youngest entry first */
int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);

/*
 * Calls the specified function for each reflog file until it returns nonzero,
 * and returns the value. Reflog file order is unspecified.
 */
int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data);
int for_each_reflog(each_ref_fn fn, void *cb_data);

#define REFNAME_ALLOW_ONELEVEL 1
#define REFNAME_REFSPEC_PATTERN 2

/*
 * Return</