diff options
Diffstat (limited to 'refs.c')
| -rw-r--r-- | refs.c | 428 |
1 files changed, 280 insertions, 148 deletions
@@ -101,11 +101,45 @@ int check_refname_format(const char *refname, int flags) struct ref_entry; +/* + * 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 { unsigned char sha1[20]; unsigned char peeled[20]; }; +struct ref_cache; + +/* + * 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; @@ -117,24 +151,41 @@ struct ref_dir { */ int sorted; + /* A pointer to the ref_cache that contains this ref_dir. */ + struct ref_cache *ref_cache; + struct ref_entry **entries; }; /* ISSYMREF=0x01, ISPACKED=0x02, and ISBROKEN=0x04 are public interfaces */ #define REF_KNOWS_PEELED 0x08 + +/* 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. 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). + * 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 @@ -171,6 +222,20 @@ struct ref_entry { char name[FLEX_ARRAY]; }; +static void read_loose_refs(const char *dirname, struct ref_dir *dir); + +static struct ref_dir *get_ref_dir(struct ref_entry *entry) +{ + struct ref_dir *dir; + assert(entry->flag & REF_DIR); + dir = &entry->u.subdir; + if (entry->flag & REF_INCOMPLETE) { + read_loose_refs(entry->name, dir); + entry->flag &= ~REF_INCOMPLETE; + } + return dir; +} + static struct ref_entry *create_ref_entry(const char *refname, const unsigned char *sha1, int flag, int check_name) @@ -194,8 +259,13 @@ static void clear_ref_dir(struct ref_dir *dir); static void free_ref_entry(struct ref_entry *entry) { - if (entry->flag & REF_DIR) + if (entry->flag & REF_DIR) { + /* + * Do not use get_ref_dir() here, as that might + * trigger the reading of loose refs. + */ clear_ref_dir(&entry->u.subdir); + } free(entry); } @@ -208,6 +278,12 @@ static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry) { ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc); dir->entries[dir->nr++] = entry; + /* optimize for the case that entries are added in order */ + if (dir->nr == 1 || + (dir->nr == dir->sorted + 1 && + strcmp(dir->entries[dir->nr - 2]->name, + dir->entries[dir->nr - 1]->name) < 0)) + dir->sorted = dir->nr; } /* @@ -228,13 +304,16 @@ static void clear_ref_dir(struct ref_dir *dir) * dirname is the name of the directory with a trailing slash (e.g., * "refs/heads/") or "" for the top-level directory. */ -static struct ref_entry *create_dir_entry(const char *dirname) +static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache, + const char *dirname, size_t len, + int incomplete) { struct ref_entry *direntry; - int len = strlen(dirname); direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1); - memcpy(direntry->name, dirname, len + 1); - direntry->flag = REF_DIR; + memcpy(direntry->name, dirname, len); + direntry->name[len] = '\0'; + direntry->u.subdir.ref_cache = ref_cache; + direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0); return direntry; } @@ -247,28 +326,42 @@ static int ref_entry_cmp(const void *a, const void *b) static void sort_ref_dir(struct ref_dir *dir); +struct string_slice { + size_t len; + const char *str; +}; + +static int ref_entry_cmp_sslice(const void *key_, const void *ent_) +{ + struct string_slice *key = (struct string_slice *)key_; + struct ref_entry *ent = *(struct ref_entry **)ent_; + int entlen = strlen(ent->name); + int cmplen = key->len < entlen ? key->len : entlen; + int cmp = memcmp(key->str, ent->name, cmplen); + if (cmp) + return cmp; + return key->len - entlen; +} + /* * Return the entry with the given refname from the ref_dir * (non-recursively), sorting dir if necessary. Return NULL if no - * such entry is found. + * such entry is found. dir must already be complete. */ -static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname) +static struct ref_entry *search_ref_dir(struct ref_dir *dir, + const char *refname, size_t len) { - struct ref_entry *e, **r; - int len; + struct ref_entry **r; + struct string_slice key; if (refname == NULL || !dir->nr) return NULL; sort_ref_dir(dir); - - len = strlen(refname) + 1; - e = xmalloc(sizeof(struct ref_entry) + len); - memcpy(e->name, refname, len); - - r = bsearch(&e, dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp); - - free(e); + key.len = len; + key.str = refname; + r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries), + ref_entry_cmp_sslice); if (r == NULL) return NULL; @@ -277,38 +370,56 @@ static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname } /* + * Search for a directory entry directly within dir (without + * recursing). Sort dir if necessary. subdirname must be a directory + * name (i.e., end in '/'). If mkdir is set, then create the + * directory if it is missing; otherwise, return NULL if the desired + * directory cannot be found. dir must already be complete. + */ +static struct ref_dir *search_for_subdir(struct ref_dir *dir, + const char *subdirname, size_t len, + int mkdir) +{ + struct ref_entry *entry = search_ref_dir(dir, subdirname, len); + if (!entry) { + if (!mkdir) + return NULL; + /* + * Since dir is complete, the absence of a subdir + * means that the subdir really doesn't exist; + * therefore, create an empty record for it but mark + * the record complete. + */ + entry = create_dir_entry(dir->ref_cache, subdirname, len, 0); + add_entry_to_dir(dir, entry); + } + return get_ref_dir(entry); +} + +/* * If refname is a reference name, find the ref_dir within the dir * tree that should hold refname. If refname is a directory name * (i.e., ends in '/'), then return that ref_dir itself. dir must - * represent the top-level directory. Sort ref_dirs and recurse into - * subdirectories as necessary. If mkdir is set, then create any - * missing directories; otherwise, return NULL if the desired - * directory cannot be found. + * represent the top-level directory and must already be complete. + * Sort ref_dirs and recurse into subdirectories as necessary. If + * mkdir is set, then create any missing directories; otherwise, + * return NULL if the desired directory cannot be found. */ static struct ref_dir *find_containing_dir(struct ref_dir *dir, const char *refname, int mkdir) { - char *refname_copy = xstrdup(refname); - char *slash; - struct ref_entry *entry; - for (slash = strchr(refname_copy, '/'); slash; slash = strchr(slash + 1, '/')) { - char tmp = slash[1]; - slash[1] = '\0'; - entry = search_ref_dir(dir, refname_copy); - if (!entry) { - if (!mkdir) { - dir = NULL; - break; - } - entry = create_dir_entry(refname_copy); - add_entry_to_dir(dir, entry); + const char *slash; + for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { + size_t dirnamelen = slash - refname + 1; + struct ref_dir *subdir; + subdir = search_for_subdir(dir, refname, dirnamelen, mkdir); + if (!subdir) { + dir = NULL; + break; } - slash[1] = tmp; - assert(entry->flag & REF_DIR); - dir = &entry->u.subdir; + dir = subdir; } - free(refname_copy); return dir; } @@ -323,7 +434,7 @@ static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname) dir = find_containing_dir(dir, refname, 0); if (!dir) return NULL; - entry = search_ref_dir(dir, refname); + entry = search_ref_dir(dir, refname, strlen(refname)); return (entry && !(entry->flag & REF_DIR)) ? entry : NULL; } @@ -434,8 +545,9 @@ static int do_for_each_ref_in_dir(struct ref_dir *dir, int offset, struct ref_entry *entry = dir->entries[i]; int retval; if (entry->flag & REF_DIR) { - sort_ref_dir(&entry->u.subdir); - retval = do_for_each_ref_in_dir(&entry->u.subdir, 0, + struct ref_dir *subdir = get_ref_dir(entry); + sort_ref_dir(subdir); + retval = do_for_each_ref_in_dir(subdir, 0, base, fn, trim, flags, cb_data); } else { retval = do_one_ref(base, fn, trim, flags, cb_data, entry); @@ -480,10 +592,12 @@ static int do_for_each_ref_in_dirs(struct ref_dir *dir1, if (cmp == 0) { if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) { /* Both are directories; descend them in parallel. */ - sort_ref_dir(&e1->u.subdir); - sort_ref_dir(&e2->u.subdir); + struct ref_dir *subdir1 = get_ref_dir(e1); + struct ref_dir *subdir2 = get_ref_dir(e2); + sort_ref_dir(subdir1); + sort_ref_dir(subdir2); retval = do_for_each_ref_in_dirs( - &e1->u.subdir, &e2->u.subdir, + subdir1, subdir2, base, fn, trim, flags, cb_data); i1++; i2++; @@ -506,9 +620,10 @@ static int do_for_each_ref_in_dirs(struct ref_dir *dir1, i2++; } if (e->flag & REF_DIR) { - sort_ref_dir(&e->u.subdir); + struct ref_dir *subdir = get_ref_dir(e); + sort_ref_dir(subdir); retval = do_for_each_ref_in_dir( - &e->u.subdir, 0, + subdir, 0, base, fn, trim, flags, cb_data); } else { retval = do_one_ref(base, fn, trim, flags, cb_data, e); @@ -592,26 +707,26 @@ static int is_refname_available(const char *refname, const char *oldrefname, */ static struct ref_cache { struct ref_cache *next; - char did_loose; - char did_packed; - struct ref_dir loose; - struct ref_dir packed; + struct ref_entry *loose; + struct ref_entry *packed; /* The submodule name, or "" for the main repo. */ char name[FLEX_ARRAY]; } *ref_cache; static void clear_packed_ref_cache(struct ref_cache *refs) { - if (refs->did_packed) - clear_ref_dir(&refs->packed); - refs->did_packed = 0; + if (refs->packed) { + free_ref_entry(refs->packed); + refs->packed = NULL; + } } static void clear_loose_ref_cache(struct ref_cache *refs) { - if (refs->did_loose) - clear_ref_dir(&refs->loose); - refs->did_loose = 0; + if (refs->loose) { + free_ref_entry(refs->loose); + refs->loose = NULL; + } } static struct ref_cache *create_ref_cache(const char *submodule) @@ -725,22 +840,22 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir) static struct ref_dir *get_packed_refs(struct ref_cache *refs) { - if (!refs->did_packed) { + if (!refs->packed) { const char *packed_refs_file; FILE *f; + refs->packed = create_dir_entry(refs, "", 0, 0); if (*refs->name) packed_refs_file = git_path_submodule(refs->name, "packed-refs"); else packed_refs_file = git_path("packed-refs"); f = fopen(packed_refs_file, "r"); if (f) { - read_packed_refs(f, &refs->packed); + read_packed_refs(f, get_ref_dir(refs->packed)); fclose(f); } - refs->did_packed = 1; } - return &refs->packed; + return get_ref_dir(refs->packed); } void add_packed_ref(const char *refname, const unsigned char *sha1) @@ -749,76 +864,90 @@ void add_packed_ref(const char *refname, const unsigned char *sha1) create_ref_entry(refname, sha1, REF_ISPACKED, 1)); } -static void get_ref_dir(struct ref_cache *refs, const char *base, - struct ref_dir *dir) +/* + * Read the loose references from the namespace dirname into dir + * (without recursing). dirname must end with '/'. dir must be the + * directory entry corresponding to dirname. + */ +static void read_loose_refs(const char *dirname, struct ref_dir *dir) { + struct ref_cache *refs = dir->ref_cache; DIR *d; const char *path; + struct dirent *de; + int dirnamelen = strlen(dirname); + struct strbuf refname; if (*refs->name) - path = git_path_submodule(refs->name, "%s", base); + path = git_path_submodule(refs->name, "%s", dirname); else - path = git_path("%s", base); + path = git_path("%s", dirname); d = opendir(path); - if (d) { - struct dirent *de; - int baselen = strlen(base); - char *refname = xmalloc(baselen + 257); - - memcpy(refname, base, baselen); - if (baselen && base[baselen-1] != '/') - refname[baselen++] = '/'; - - while ((de = readdir(d)) != NULL) { - unsigned char sha1[20]; - struct stat st; - int flag; - int namelen; - const char *refdir; - - if (de->d_name[0] == '.') - continue; - namelen = strlen(de->d_name); - if (namelen > 255) - continue; - if (has_extension(de->d_name, ".lock")) - continue; - memcpy(refname + baselen, de->d_name, namelen+1); - refdir = *refs->name - ? git_path_submodule(refs->name, "%s", refname) - : git_path("%s", refname); - if (stat(refdir, &st) < 0) - continue; - if (S_ISDIR(st.st_mode)) { - get_ref_dir(refs, refname, dir); - continue; - } + if (!d) + return; + + strbuf_init(&refname, dirnamelen + 257); + strbuf_add(&refname, dirname, dirnamelen); + + while ((de = readdir(d)) != NULL) { + unsigned char sha1[20]; + struct stat st; + int flag; + const char *refdir; + + if (de->d_name[0] == '.') + continue; + if (has_extension(de->d_name, ".lock")) + continue; + strbuf_addstr(&refname, de->d_name); + refdir = *refs->name + ? git_path_submodule(refs->name, "%s", refname.buf) + : git_path("%s", refname.buf); + if (stat(refdir, &st) < 0) { + ; /* silently ignore */ + } else if (S_ISDIR(st.st_mode)) { + strbuf_addch(&refname, '/'); + add_entry_to_dir(dir, + create_dir_entry(refs, refname.buf, + refname.len, 1)); + } else { if (*refs->name) { hashclr(sha1); flag = 0; - if (resolve_gitlink_ref(refs->name, refname, sha1) < 0) { + if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) { hashclr(sha1); flag |= REF_ISBROKEN; } - } else if (read_ref_full(refname, sha1, 1, &flag)) { + } else if (read_ref_full(refname.buf, sha1, 1, &flag)) { hashclr(sha1); flag |= REF_ISBROKEN; } - add_ref(dir, create_ref_entry(refname, sha1, flag, 1)); + add_entry_to_dir(dir, + create_ref_entry(refname.buf, sha1, flag, 1)); } - free(refname); - closedir(d); + strbuf_setlen(&refname, dirnamelen); } + strbuf_release(&refname); + closedir(d); } static struct ref_dir *get_loose_refs(struct ref_cache *refs) { - if (!refs->did_loose) { - get_ref_dir(refs, "refs", &refs->loose); - refs->did_loose = 1; + if (!refs->loose) { + /* + * Mark the top-level directory complete because we + * are about to read the only subdirectory that can + * hold references: + */ + refs->loose = create_dir_entry(refs, "", 0, 0); + /* + * Create an incomplete entry for "refs/": + */ + add_entry_to_dir(get_ref_dir(refs->loose), + create_dir_entry(refs, "refs/", 5, 1)); } - return &refs->loose; + return get_ref_dir(refs->loose); } /* We allow "recursive" symbolic refs. Only within reason, though */ @@ -1126,6 +1255,7 @@ static int warn_if_dangling_symref(const char *refname, const unsigned char *sha return 0; fprintf(d->fp, d->msg_fmt, refname); + fputc('\n', d->fp); return 0; } @@ -2223,57 +2353,59 @@ int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_dat return for_each_recent_reflog_ent(refname, fn, 0, cb_data); } -static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data) +/* + * Call fn for each reflog in the namespace indicated by name. name + * must be empty or end with '/'. Name will be used as a scratch + * space, but its contents will be restored before return. + */ +static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data) { - DIR *d = opendir(git_path("logs/%s", base)); + DIR *d = opendir(git_path("logs/%s", name->buf)); int retval = 0; + struct dirent *de; + int oldlen = name->len; - if (d) { - struct dirent *de; - int baselen = strlen(base); - char *log = xmalloc(baselen + 257); - - memcpy(log, base, baselen); - if (baselen && base[baselen-1] != '/') - log[baselen++] = '/'; + if (!d) + return name->len ? errno : 0; - while ((de = readdir(d)) != NULL) { - struct stat st; - int namelen; + while ((de = readdir(d)) != NULL) { + struct stat st; - if (de->d_name[0] == '.') - continue; - namelen = strlen(de->d_name); - if (namelen > 255) - continue; - if (has_extension(de->d_name, ".lock")) - continue; - memcpy(log + baselen, de->d_name, namelen+1); - if (stat(git_path("logs/%s", log), &st) < 0) - continue; + if (de->d_name[0] == '.') + continue; + if (has_extension(de->d_name, ".lock")) + continue; + strbuf_addstr(name, de->d_name); + if (stat(git_path("logs/%s", name->buf), &st) < 0) { + ; /* silently ignore */ + } else { if (S_ISDIR(st.st_mode)) { - retval = do_for_each_reflog(log, fn, cb_data); + strbuf_addch(name, '/'); + retval = do_for_each_reflog(name, fn, cb_data); } else { unsigned char sha1[20]; - if (read_ref_full(log, sha1, 0, NULL)) - retval = error("bad ref for %s", log); + if (read_ref_full(name->buf, sha1, 0, NULL)) + retval = error("bad ref for %s", name->buf); else - retval = fn(log, sha1, 0, cb_data); + retval = fn(name->buf, sha1, 0, cb_data); } if (retval) break; } - free(log); - closedir(d); + strbuf_setlen(name, oldlen); } - else if (*base) - return errno; + closedir(d); return retval; } int for_each_reflog(each_ref_fn fn, void *cb_data) { - return do_for_each_reflog("", fn, cb_data); + int retval; + struct strbuf name; + strbuf_init(&name, PATH_MAX); + retval = do_for_each_reflog(&name, fn, cb_data); + strbuf_release(&name); + return retval; } int update_ref(const char *action, const char *refname, |