git/refs.h
Michael Haggerty 1c03c4d347 delete_ref(): use the usual convention for old_sha1
The ref_transaction_update() family of functions use the following
convention for their old_sha1 parameters:

* old_sha1 == NULL: Don't check the old value at all.
* is_null_sha1(old_sha1): Ensure that the reference didn't exist
  before the transaction.
* otherwise: Ensure that the reference had the specified value before
  the transaction.

delete_ref() had a different convention, namely treating
is_null_sha1(old_sha1) as "don't care". Change it to adhere to the
standard convention to reduce the scope for confusion.

Please note that it is now a bug to pass old_sha1=NULL_SHA1 to
delete_ref() (because it doesn't make sense to delete a reference that
you already know doesn't exist). This is consistent with the behavior
of ref_transaction_delete().

Most of the callers of delete_ref() never pass old_sha1=NULL_SHA1 to
delete_ref(), and are therefore unaffected by this change. The
two exceptions are:

* The call in cmd_update_ref(), which passed NULL_SHA1 if the old
  value passed in on the command line was 0{40} or the empty string.
  Change that caller to pass NULL in those cases.

  Arguably, it should be an error to call "update-ref -d" with the old
  value set to "does not exist", just as it is for the `--stdin`
  command "delete". But since this usage was accepted until now,
  continue to accept it.

* The call in delete_branches(), which could pass NULL_SHA1 if
  deleting a broken or symbolic ref. Change it to pass NULL in these
  cases.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-22 13:17:14 -07:00

494 lines
18 KiB
C

#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
extern const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
unsigned char *sha1, int *flags);
extern char *resolve_refdup(const char *refname, int resolve_flags,
unsigned char *sha1, int *flags);
extern int read_ref_full(const char *refname, int resolve_flags,
unsigned char *sha1, int *flags);
extern int read_ref(const char *refname, unsigned char *sha1);
extern int ref_exists(const char *refname);
extern 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.
*/
extern 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.
*/
extern 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.
*/
extern int refname_match(const char *abbrev_name, const char *full_name);
extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
extern 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.
*
* - 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;
/*
* Bit values set in the flags argument passed to each_ref_fn():
*/
/* 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.
*/
extern int head_ref(each_ref_fn fn, void *cb_data);
extern int for_each_ref(each_ref_fn fn, void *cb_data);
extern int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
extern int for_each_tag_ref(each_ref_fn fn, void *cb_data);
extern int for_each_branch_ref(each_ref_fn fn, void *cb_data);
extern int for_each_remote_ref(each_ref_fn fn, void *cb_data);
extern int for_each_replace_ref(each_ref_fn fn, void *cb_data);
extern int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
extern int for_each_glob_ref_in(each_ref_fn fn, const char *pattern, const char *prefix, void *cb_data);
extern int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_ref_in_submodule(const char *submodule, const char *prefix,
each_ref_fn fn, void *cb_data);
extern int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
extern int head_ref_namespaced(each_ref_fn fn, void *cb_data);
extern int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
/* can be used to learn about broken ref and symref */
extern int for_each_rawref(each_ref_fn fn, void *cb_data);
static inline const char *has_glob_specials(const char *pattern)
{
return strpbrk(pattern, "?*[");
}
extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
extern 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
/*
* Setup reflog before using. Set errno to something meaningful on failure.
*/
int log_ref_setup(const char *refname, struct strbuf *logfile);
/** Reads log for the value of ref during at_time. **/
extern 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 */
extern 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().
*/
extern 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).
*/
extern int delete_refs(struct string_list *refnames);
/** Delete a reflog */
extern int delete_reflog(const char *refname);
/* iterate over reflog entries */
typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
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
*/
extern int for_each_reflog(each_ref_fn, void *);
#define REFNAME_ALLOW_ONELEVEL 1
#define REFNAME_REFSPEC_PATTERN 2
/*
* Return 0 iff refname has the correct format for a refname according
* to the rules described in Documentation/git-check-ref-format.txt.
* If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
* reference names. If REFNAME_REFSPEC_PATTERN is set in flags, then
* allow a "*" wildcard character in place of one of the name
* components. No leading or repeated slashes are accepted.
*/
extern int check_refname_format(const char *refname, int flags);
extern const char *prettify_refname(const char *refname);
extern char *shorten_unambiguous_ref(const char *refname, int strict);
/** rename ref, return 0 on success **/
extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
extern int create_symref(const char *ref, const char *refs_heads_master, const char *logmsg);
enum action_on_err {
UPDATE_REFS_MSG_ON_ERR,
UPDATE_REFS_DIE_ON_ERR,
UPDATE_REFS_QUIET_ON_ERR
};
/*
* Begin a reference transaction. The reference transaction must
* be freed by calling ref_transaction_free().
*/
struct ref_transaction *ref_transaction_begin(struct strbuf *err);
/*
* Reference transaction updates
*
* The following four functions add a reference check or update to a
* ref_transaction. They have some common similar parameters:
*
* transaction -- a pointer to an open ref_transaction, obtained
* from ref_transaction_begin().
*
* refname -- the name of the reference to be affected.
*
* flags -- flags affecting the update, passed to
* update_ref_lock(). Can be REF_NODEREF, which means that
* symbolic references should not be followed.
*
* msg -- a message describing the change (for the reflog).
*
* err -- a strbuf for receiving a description of any error that
* might have occured.
*
* The functions make internal copies of refname and msg, so the
* caller retains ownership of these parameters.
*
* The functions return 0 on success and non-zero on failure. A
* failure means that the transaction as a whole has failed and needs
* to be rolled back.
*/
/*
* Add a reference update to transaction. new_sha1 is the value that
* the reference should have after the update, or null_sha1 if it
* should be deleted. If new_sha1 is NULL, then the reference is not
* changed at all. old_sha1 is the value that the reference must have
* before the update, or null_sha1 if it must not have existed
* beforehand. The old value is checked after the lock is taken to
* prevent races. If the old value doesn't agree with old_sha1, the
* whole transaction fails. If old_sha1 is NULL, then the previous
* value is not checked.
*
* See the above comment "Reference transaction updates" for more
* information.
*/
int ref_transaction_update(struct ref_transaction *transaction,
const char *refname,
const unsigned char *new_sha1,
const unsigned char *old_sha1,
unsigned int flags, const char *msg,
struct strbuf *err);
/*
* Add a reference creation to transaction. new_sha1 is the value that
* the reference should have after the update; it must not be
* null_sha1. It is verified that the reference does not exist
* already.
*
* See the above comment "Reference transaction updates" for more
* information.
*/
int ref_transaction_create(struct ref_transaction *transaction,
const char *refname,
const unsigned char *new_sha1,
unsigned int flags, const char *msg,
struct strbuf *err);
/*
* Add a reference deletion to transaction. If old_sha1 is non-NULL,
* then it holds the value that the reference should have had before
* the update (which must not be null_sha1).
*
* See the above comment "Reference transaction updates" for more
* information.
*/
int ref_transaction_delete(struct ref_transaction *transaction,
const char *refname,
const unsigned char *old_sha1,
unsigned int flags, const char *msg,
struct strbuf *err);
/*
* Verify, within a transaction, that refname has the value old_sha1,
* or, if old_sha1 is null_sha1, then verify that the reference
* doesn't exist. old_sha1 must be non-NULL.
*
* See the above comment "Reference transaction updates" for more
* information.
*/
int ref_transaction_verify(struct ref_transaction *transaction,
const char *refname,
const unsigned char *old_sha1,
unsigned int flags,
struct strbuf *err);
/*
* Commit all of the changes that have been queued in transaction, as
* atomically as possible.
*
* Returns 0 for success, or one of the below error codes for errors.
*/
/* Naming conflict (for example, the ref names A and A/B conflict). */
#define TRANSACTION_NAME_CONFLICT -1
/* All other errors. */
#define TRANSACTION_GENERIC_ERROR -2
int ref_transaction_commit(struct ref_transaction *transaction,
struct strbuf *err);
/*
* Like ref_transaction_commit(), but optimized for creating
* references when originally initializing a repository (e.g., by "git
* clone"). It writes the new references directly to packed-refs
* without locking the individual references.
*
* It is a bug to call this function when there might be other
* processes accessing the repository or if there are existing
* references that might conflict with the ones being created. All
* old_sha1 values must either be absent or NULL_SHA1.
*/
int initial_ref_transaction_commit(struct ref_transaction *transaction,
struct strbuf *err);
/*
* Free an existing transaction and all associated data.
*/
void ref_transaction_free(struct ref_transaction *transaction);
/**
* Lock, update, and unlock a single reference. This function
* basically does a transaction containing a single call to
* ref_transaction_update(). The parameters to this function have the
* same meaning as the corresponding parameters to
* ref_transaction_update(). Handle errors as requested by the `onerr`
* argument.
*/
int update_ref(const char *msg, const char *refname,
const unsigned char *new_sha1, const unsigned char *old_sha1,
unsigned int flags, enum action_on_err onerr);
extern int parse_hide_refs_config(const char *var, const char *value, const char *);
extern int ref_is_hidden(const char *);
enum expire_reflog_flags {
EXPIRE_REFLOGS_DRY_RUN = 1 << 0,
EXPIRE_REFLOGS_UPDATE_REF = 1 << 1,
EXPIRE_REFLOGS_VERBOSE = 1 << 2,
EXPIRE_REFLOGS_REWRITE = 1 << 3
};
/*
* The following interface is used for reflog expiration. The caller
* calls reflog_expire(), supplying it with three callback functions,
* of the following types. The callback functions define the
* expiration policy that is desired.
*
* reflog_expiry_prepare_fn -- Called once after the reference is
* locked.
*
* reflog_expiry_should_prune_fn -- Called once for each entry in the
* existing reflog. It should return true iff that entry should be
* pruned.
*
* reflog_expiry_cleanup_fn -- Called once before the reference is
* unlocked again.
*/
typedef void reflog_expiry_prepare_fn(const char *refname,
const unsigned char *sha1,
void *cb_data);
typedef int reflog_expiry_should_prune_fn(unsigned char *osha1,
unsigned char *nsha1,
const char *email,
unsigned long timestamp, int tz,
const char *message, void *cb_data);
typedef void reflog_expiry_cleanup_fn(void *cb_data);
/*
* Expire reflog entries for the specified reference. sha1 is the old
* value of the reference. flags is a combination of the constants in
* enum expire_reflog_flags. The three function pointers are described
* above. On success, return zero.
*/
extern int reflog_expire(const char *refname, const unsigned char *sha1,
unsigned int flags,
reflog_expiry_prepare_fn prepare_fn,
reflog_expiry_should_prune_fn should_prune_fn,
reflog_expiry_cleanup_fn cleanup_fn,
void *policy_cb_data);
#endif /* REFS_H */