#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, int incomplete); 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); /* * Remove the entry with the given name from dir, recursing into * subdirectories as necessary. If refname is the name of a directory * (i.e., ends with '/'), then remove the directory and its contents. * If the removal was successful, return the number of entries * remaining in the directory entry that contained the deleted entry. * If the name was not found, return -1. Please note that this * function only deletes the entry from the cache; it does not delete * it from the filesystem or ensure that other cache entries (which * might be symbolic references to the removed entry) are updated. * Nor does it remove any containing dir entries that might be made * empty by the removal. dir must represent the top-level directory * and must already be complete. */ int remove_entry_from_dir(struct ref_dir *dir, const char *refname); /* * Add a ref_entry to the ref_dir (unsorted), recursing into * subdirectories as necessary. dir must represent the top-level * directory. Return 0 on success. */ int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref); /* * 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, int prime_dir); #endif /* REFS_REF_CACHE_H */