path: root/refs.h

#ifndef REFS_H
#define REFS_H

/*
 * Resolve a reference, recursively following symbolic refererences.
 *
 * Store the referred-to object's name in sha1 and return the name of
 * the non-symbolic reference that ultimately pointed at it.  The
 * return value, if not NULL, is a pointer into either a static buffer
 * or the input ref.
 *
 * 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 sha1 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 sha1 for a symbolic
 * reference will always be null_sha1 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 sha1 will be null_sha1 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

const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
			       unsigned char *sha1, int *flags);

char *resolve_refdup(const char *refname, int resolve_flags,
		     unsigned char *sha1, int *flags);

int read_ref_full(const char *refname, int resolve_flags,
		  unsigned char *sha1, int *flags);
int read_ref(const char *refname, unsigned char *sha1);

int ref_exists(const char *refname);

int is_branch(const char *refname);

/*
 * If refname is a non-symbolic reference that refers to a tag object,
 * and the tag can be (recursively) dereferenced to a non-tag object,
 * store the SHA1 of the referred-to object to sha1 and return 0.  If
 * any of these conditions are not met, return a non-zero value.
 * Symbolic references are considered unpeelable, even if they
 * ultimately resolve to a peelable tag.
 */
int peel_ref(const char *refname, unsigned char *sha1);

/**
 * Resolve refname in the nested "gitlink" repository that is located
 * at path.  If the resolution is successful, return 0 and set sha1 to
 * the name of the object; otherwise, return a non-zero value.
 */
int resolve_gitlink_ref(const char *path, const char *refname,
			unsigned char *sha1);

/*
 * 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);

int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);

/*
 * 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.
 *
 * - Instead of `ref_transaction_commit`, use
 *   `initial_ref_transaction_commit()` if the ref database is known
 *   to be empty (e.g. during clone).  This is likely to be much
 *   faster.
 *
 * - 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.
 *
 * Caveats
 * -------
 *
 * Note that no locks are taken, and no refs are read, until
 * `ref_transaction_commit` is called.  So `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 sha1
 * 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 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.
 */
int head_ref(each_ref_fn fn, void *cb_data);
int for_each_ref(each_ref_fn fn, void *cb_data);
int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
			unsigned int broken);
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(each_ref_fn fn, void *cb_data);
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_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
int for_each_ref_submodule(const char *submodule,
			   each_ref_fn fn, void *cb_data);
int for_each_ref_in_submodule(const char *submodule, const char *prefix,
		each_ref_fn fn, void *cb_data);
int for_each_tag_ref_submodule(const char *submodule,
			       each_ref_fn fn, void *cb_data);
int for_each_branch_ref_submodule(const char *submodule,
				  each_ref_fn fn, void *cb_data);
int for_each_remote_ref_submodule(const char *submodule,
				  each_ref_fn fn, void *cb_data);

int head_ref_namespaced(each_ref_fn fn, void *cb_data);
int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);

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

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 pack_refs(unsigned int flags);

/*
 * Flags controlling ref_transaction_update(), ref_transaction_create(), etc.
 * REF_NODEREF: act on the ref directly, instead of dereferencing
 *              symbolic references.
 *
 * Other flags are reserved for internal use.
 */
#define REF_NODEREF	0x01
#define REF_FORCE_CREATE_REFLOG 0x40

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

/** Reads log for the value of ref during at_time. **/
int read_ref_at(const char *refname, unsigned int flags,
		unsigned long at_time, int cnt,
		unsigned char *sha1, char **msg,
		unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);

/** Check if a particular reflog exists */
int reflog_exists(const char *refname);

/*
 * Delete the specified reference. If old_sha1 is non-NULL, then
 * verify that the current value of the reference is old_sha1 before
 * deleting it. If old_sha1 is NULL, delete the reference if it
 * exists, regardless of its old value. It is an error for old_sha1 to
 * be NULL_SHA1. flags is passed through to ref_transaction_delete().
 */
int delete_ref(const char *refname, const unsigned char *old_sha1,
	       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). flags is passed through to
 * ref_transaction_delete().
 */
int delete_refs(struct string_list *refnames, unsigned int flags);

/** Delete a reflog */
int delete_reflog(const char *refname);

/* iterate over reflog entries */
typedef int each_reflog_ent_fn(
		unsigned char *old_sha1, unsigned char *new_sha1,
		const char *committer, unsigned long timestamp,
		int tz, const char *msg, void *cb_data);
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