| #ifndef REFS_REF_CACHE_H |
| #define REFS_REF_CACHE_H |
| |
| #include "cache.h" |
| |
| struct ref_dir; |
| struct ref_store; |
| |
| /* |
| * If this ref_cache is filled lazily, this function is used to load |
| * information into the specified ref_dir (shallow or deep, at the |
| * option of the ref_store). dirname includes a trailing slash. |
| */ |
| typedef void fill_ref_dir_fn(struct ref_store *ref_store, |
| struct ref_dir *dir, const char *dirname); |
| |
| struct ref_cache { |
| struct ref_entry *root; |
| |
| /* A pointer to the ref_store whose cache this is: */ |
| struct ref_store *ref_store; |
| |
| /* |
| * Function used (if necessary) to lazily-fill cache. May be |
| * NULL. |
| */ |
| fill_ref_dir_fn *fill_ref_dir; |
| }; |
| |
| /* |
| * Information used (along with the information in ref_entry) to |
| * describe a single cached reference. This data structure only |
| * occurs embedded in a union in struct ref_entry, and only when |
| * (ref_entry->flag & REF_DIR) is zero. |
| */ |
| struct ref_value { |
| /* |
| * The name of the object to which this reference resolves |
| * (which may be a tag object). If REF_ISBROKEN, this is |
| * null. If REF_ISSYMREF, then this is the name of the object |
| * referred to by the last reference in the symlink chain. |
| */ |
| struct object_id oid; |
| }; |
| |
| /* |
| * Information used (along with the information in ref_entry) to |
| * describe a level in the hierarchy of references. This data |
| * structure only occurs embedded in a union in struct ref_entry, and |
| * only when (ref_entry.flag & REF_DIR) is set. In that case, |
| * (ref_entry.flag & REF_INCOMPLETE) determines whether the references |
| * in the directory have already been read: |
| * |
| * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose |
| * or packed references, already read. |
| * |
| * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose |
| * references that hasn't been read yet (nor has any of its |
| * subdirectories). |
| * |
| * Entries within a directory are stored within a growable array of |
| * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i < |
| * sorted are sorted by their component name in strcmp() order and the |
| * remaining entries are unsorted. |
| * |
| * Loose references are read lazily, one directory at a time. When a |
| * directory of loose references is read, then all of the references |
| * in that directory are stored, and REF_INCOMPLETE stubs are created |
| * for any subdirectories, but the subdirectories themselves are not |
| * read. The reading is triggered by get_ref_dir(). |
| */ |
| struct ref_dir { |
| int nr, alloc; |
| |
| /* |
| * Entries with index 0 <= i < sorted are sorted by name. New |
| * entries are appended to the list unsorted, and are sorted |
| * only when required; thus we avoid the need to sort the list |
| * after the addition of every reference. |
| */ |
| int sorted; |
| |
| /* The ref_cache containing this entry: */ |
| struct ref_cache *cache; |
| |
| struct ref_entry **entries; |
| }; |
| |
| /* |
| * Bit values for ref_entry::flag. REF_ISSYMREF=0x01, |
| * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are |
| * public values; see refs.h. |
| */ |
| |
| /* ref_entry represents a directory of references */ |
| #define REF_DIR 0x10 |
| |
| /* |
| * Entry has not yet been read from disk (used only for REF_DIR |
| * entries representing loose references) |
| */ |
| #define REF_INCOMPLETE 0x20 |
| |
| /* |
| * A ref_entry represents either a reference or a "subdirectory" of |
| * references. |
| * |
| * Each directory in the reference namespace is represented by a |
| * ref_entry with (flags & REF_DIR) set and containing a subdir member |
| * that holds the entries in that directory that have been read so |
| * far. If (flags & REF_INCOMPLETE) is set, then the directory and |
| * its subdirectories haven't been read yet. REF_INCOMPLETE is only |
| * used for loose reference directories. |
| * |
| * References are represented by a ref_entry with (flags & REF_DIR) |
| * unset and a value member that describes the reference's value. The |
| * flag member is at the ref_entry level, but it is also needed to |
| * interpret the contents of the value field (in other words, a |
| * ref_value object is not very much use without the enclosing |
| * ref_entry). |
| * |
| * Reference names cannot end with slash and directories' names are |
| * always stored with a trailing slash (except for the top-level |
| * directory, which is always denoted by ""). This has two nice |
| * consequences: (1) when the entries in each subdir are sorted |
| * lexicographically by name (as they usually are), the references in |
| * a whole tree can be generated in lexicographic order by traversing |
| * the tree in left-to-right, depth-first order; (2) the names of |
| * references and subdirectories cannot conflict, and therefore the |
| * presence of an empty subdirectory does not block the creation of a |
| * similarly-named reference. (The fact that reference names with the |
| * same leading components can conflict *with each other* is a |
| * separate issue that is regulated by refs_verify_refname_available().) |
| * |
| * Please note that the name field contains the fully-qualified |
| * reference (or subdirectory) name. Space could be saved by only |
| * storing the relative names. But that would require the full names |
| * to be generated on the fly when iterating in do_for_each_ref(), and |
| * would break callback functions, who have always been able to assume |
| * that the name strings that they are passed will not be freed during |
| * the iteration. |
| */ |
| struct ref_entry { |
| unsigned char flag; /* ISSYMREF? ISPACKED? */ |
| union { |
| struct ref_value value; /* if not (flags&REF_DIR) */ |
| struct ref_dir subdir; /* if (flags&REF_DIR) */ |
| } u; |
| /* |
| * The full name of the reference (e.g., "refs/heads/master") |
| * or the full name of the directory with a trailing slash |
| * (e.g., "refs/heads/"): |
| */ |
| char name[FLEX_ARRAY]; |
| }; |
| |
| /* |
| * Return the index of the entry with the given refname from the |
| * ref_dir (non-recursively), sorting dir if necessary. Return -1 if |
| * no such entry is found. dir must already be complete. |
| */ |
| int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len); |
| |
| struct ref_dir *get_ref_dir(struct ref_entry *entry); |
| |
| /* |
| * Create a struct ref_entry object for the specified dirname. |
| * dirname is the name of the directory with a trailing slash (e.g., |
| * "refs/heads/") or "" for the top-level directory. |
| */ |
| struct ref_entry *create_dir_entry(struct ref_cache *cache, |
| const char *dirname, size_t len); |
| |
| struct ref_entry *create_ref_entry(const char *refname, |
| const struct object_id *oid, int flag); |
| |
| /* |
| * Return a pointer to a new `ref_cache`. Its top-level starts out |
| * marked incomplete. If `fill_ref_dir` is non-NULL, it is the |
| * function called to fill in incomplete directories in the |
| * `ref_cache` when they are accessed. If it is NULL, then the whole |
| * `ref_cache` must be filled (including clearing its directories' |
| * `REF_INCOMPLETE` bits) before it is used, and `refs` can be NULL, |
| * too. |
| */ |
| struct ref_cache *create_ref_cache(struct ref_store *refs, |
| fill_ref_dir_fn *fill_ref_dir); |
| |
| /* |
| * Free the `ref_cache` and all of its associated data. |
| */ |
| void free_ref_cache(struct ref_cache *cache); |
| |
| /* |
| * Add a ref_entry to the end of dir (unsorted). Entry is always |
| * stored directly in dir; no recursion into subdirectories is |
| * done. |
| */ |
| void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry); |
| |
| /* |
| * Find the value entry with the given name in dir, sorting ref_dirs |
| * and recursing into subdirectories as necessary. If the name is not |
| * found or it corresponds to a directory entry, return NULL. |
| */ |
| struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname); |
| |
| /* |
| * Start iterating over references in `cache`. If `prefix` is |
| * specified, only include references whose names start with that |
| * prefix. If `prime_dir` is true, then fill any incomplete |
| * directories before beginning the iteration. The output is ordered |
| * by refname. |
| */ |
| struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache, |
| const char *prefix, |
| struct repository *repo, |
| int prime_dir); |
| |
| #endif /* REFS_REF_CACHE_H */ |