refs/refs-internal.h

   1 #ifndef REFS_REFS_INTERNAL_H
   2 #define REFS_REFS_INTERNAL_H
   3
   4 /*
   5  * Data structures and functions for the internal use of the refs
   6  * module. Code outside of the refs module should use only the public
   7  * functions defined in "refs.h", and should *not* include this file.
   8  */
   9
  10 /*
  11  * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
  12  * refs (i.e., because the reference is about to be deleted anyway).
  13  */
  14 #define REF_DELETING    0x02
  15
  16 /*
  17  * Used as a flag in ref_update::flags when a loose ref is being
  18  * pruned.
  19  */
  20 #define REF_ISPRUNING   0x04
  21
  22 /*
  23  * Used as a flag in ref_update::flags when the reference should be
  24  * updated to new_sha1.
  25  */
  26 #define REF_HAVE_NEW    0x08
  27
  28 /*
  29  * Used as a flag in ref_update::flags when old_sha1 should be
  30  * checked.
  31  */
  32 #define REF_HAVE_OLD    0x10
  33
  34 /*
  35  * Used as a flag in ref_update::flags when the lockfile needs to be
  36  * committed.
  37  */
  38 #define REF_NEEDS_COMMIT 0x20
  39
  40 /*
  41  * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
  42  * value to ref_update::flags
  43  */
  44
  45 /*
  46  * Return true iff refname is minimally safe. "Safe" here means that
  47  * deleting a loose reference by this name will not do any damage, for
  48  * example by causing a file that is not a reference to be deleted.
  49  * This function does not check that the reference name is legal; for
  50  * that, use check_refname_format().
  51  *
  52  * We consider a refname that starts with "refs/" to be safe as long
  53  * as any ".." components that it might contain do not escape "refs/".
  54  * Names that do not start with "refs/" are considered safe iff they
  55  * consist entirely of upper case characters and '_' (like "HEAD" and
  56  * "MERGE_HEAD" but not "config" or "FOO/BAR").
  57  */
  58 int refname_is_safe(const char *refname);
  59
  60 enum peel_status {
  61         /* object was peeled successfully: */
  62         PEEL_PEELED = 0,
  63
  64         /*
  65          * object cannot be peeled because the named object (or an
  66          * object referred to by a tag in the peel chain), does not
  67          * exist.
  68          */
  69         PEEL_INVALID = -1,
  70
  71         /* object cannot be peeled because it is not a tag: */
  72         PEEL_NON_TAG = -2,
  73
  74         /* ref_entry contains no peeled value because it is a symref: */
  75         PEEL_IS_SYMREF = -3,
  76
  77         /*
  78          * ref_entry cannot be peeled because it is broken (i.e., the
  79          * symbolic reference cannot even be resolved to an object
  80          * name):
  81          */
  82         PEEL_BROKEN = -4
  83 };
  84
  85 /*
  86  * Peel the named object; i.e., if the object is a tag, resolve the
  87  * tag recursively until a non-tag is found.  If successful, store the
  88  * result to sha1 and return PEEL_PEELED.  If the object is not a tag
  89  * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
  90  * and leave sha1 unchanged.
  91  */
  92 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
  93
  94 /*
  95  * Return 0 if a reference named refname could be created without
  96  * conflicting with the name of an existing reference. Otherwise,
  97  * return a negative value and write an explanation to err. If extras
  98  * is non-NULL, it is a list of additional refnames with which refname
  99  * is not allowed to conflict. If skip is non-NULL, ignore potential
 100  * conflicts with refs in skip (e.g., because they are scheduled for
 101  * deletion in the same operation). Behavior is undefined if the same
 102  * name is listed in both extras and skip.
 103  *
 104  * Two reference names conflict if one of them exactly matches the
 105  * leading components of the other; e.g., "foo/bar" conflicts with
 106  * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 107  * "foo/barbados".
 108  *
 109  * extras and skip must be sorted.
 110  */
 111 int verify_refname_available(const char *newname,
 112                              struct string_list *extras,
 113                              struct string_list *skip,
 114                              struct strbuf *err);
 115
 116 /*
 117  * Copy the reflog message msg to buf, which has been allocated sufficiently
 118  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
 119  * because reflog file is one line per entry.
 120  */
 121 int copy_reflog_msg(char *buf, const char *msg);
 122
 123 int should_autocreate_reflog(const char *refname);
 124
 125 /**
 126  * Information needed for a single ref update. Set new_sha1 to the new
 127  * value or to null_sha1 to delete the ref. To check the old value
 128  * while the ref is locked, set (flags & REF_HAVE_OLD) and set
 129  * old_sha1 to the old value, or to null_sha1 to ensure the ref does
 130  * not exist before update.
 131  */
 132 struct ref_update {
 133         /*
 134          * If (flags & REF_HAVE_NEW), set the reference to this value:
 135          */
 136         unsigned char new_sha1[20];
 137         /*
 138          * If (flags & REF_HAVE_OLD), check that the reference
 139          * previously had this value:
 140          */
 141         unsigned char old_sha1[20];
 142         /*
 143          * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
 144          * REF_DELETING, and REF_ISPRUNING:
 145          */
 146         unsigned int flags;
 147         struct ref_lock *lock;
 148         int type;
 149         char *msg;
 150         const char refname[FLEX_ARRAY];
 151 };
 152
 153 /*
 154  * Transaction states.
 155  * OPEN:   The transaction is in a valid state and can accept new updates.
 156  *         An OPEN transaction can be committed.
 157  * CLOSED: A closed transaction is no longer active and no other operations
 158  *         than free can be used on it in this state.
 159  *         A transaction can either become closed by successfully committing
 160  *         an active transaction or if there is a failure while building
 161  *         the transaction thus rendering it failed/inactive.
 162  */
 163 enum ref_transaction_state {
 164         REF_TRANSACTION_OPEN   = 0,
 165         REF_TRANSACTION_CLOSED = 1
 166 };
 167
 168 /*
 169  * Data structure for holding a reference transaction, which can
 170  * consist of checks and updates to multiple references, carried out
 171  * as atomically as possible.  This structure is opaque to callers.
 172  */
 173 struct ref_transaction {
 174         struct ref_update **updates;
 175         size_t alloc;
 176         size_t nr;
 177         enum ref_transaction_state state;
 178 };
 179
 180 #endif /* REFS_REFS_INTERNAL_H */