From 685b2925757e98624e37abe09d49c205a7db5943 Mon Sep 17 00:00:00 2001 From: Brandon Williams Date: Fri, 27 Jan 2017 18:02:02 -0800 Subject: attr: eliminate global check_all_attr array Currently there is a reliance on 'check_all_attr' which is a global array of 'attr_check_item' items which is used to store the value of each attribute during the collection process. This patch eliminates this global and instead creates an array per 'attr_check' instance which is then used in the attribute collection process. This brings the attribute system one step closer to being thread-safe. Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano --- attr.c | 121 ++++++++++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 82 insertions(+), 39 deletions(-) (limited to 'attr.c') diff --git a/attr.c b/attr.c index e008f3026..2637804b1 100644 --- a/attr.c +++ b/attr.c @@ -34,7 +34,6 @@ struct git_attr { int maybe_real; char name[FLEX_ARRAY]; /* attribute name */ }; -static int attr_nr; /* * NEEDSWORK: maybe-real, maybe-macro are not property of @@ -45,9 +44,6 @@ static int attr_nr; */ static int cannot_trust_maybe_real; -/* NEEDSWORK: This will become per git_attr_check */ -static struct attr_check_item *check_all_attr; - const char *git_attr_name(const struct git_attr *attr) { return attr->name; @@ -143,6 +139,57 @@ static void attr_hashmap_add(struct attr_hashmap *map, hashmap_add(&map->map, e); } +struct all_attrs_item { + const struct git_attr *attr; + const char *value; +}; + +/* + * Reallocate and reinitialize the array of all attributes (which is used in + * the attribute collection process) in 'check' based on the global dictionary + * of attributes. + */ +static void all_attrs_init(struct attr_hashmap *map, struct attr_check *check) +{ + int i; + + hashmap_lock(map); + + if (map->map.size < check->all_attrs_nr) + die("BUG: interned attributes shouldn't be deleted"); + + /* + * If the number of attributes in the global dictionary has increased + * (or this attr_check instance doesn't have an initialized all_attrs + * field), reallocate the provided attr_check instance's all_attrs + * field and fill each entry with its corresponding git_attr. + */ + if (map->map.size != check->all_attrs_nr) { + struct attr_hash_entry *e; + struct hashmap_iter iter; + hashmap_iter_init(&map->map, &iter); + + REALLOC_ARRAY(check->all_attrs, map->map.size); + check->all_attrs_nr = map->map.size; + + while ((e = hashmap_iter_next(&iter))) { + const struct git_attr *a = e->value; + check->all_attrs[a->attr_nr].attr = a; + } + } + + hashmap_unlock(map); + + /* + * Re-initialize every entry in check->all_attrs. + * This re-initialization can live outside of the locked region since + * the attribute dictionary is no longer being accessed. + */ + for (i = 0; i < check->all_attrs_nr; i++) { + check->all_attrs[i].value = ATTR__UNKNOWN; + } +} + static int attr_name_valid(const char *name, size_t namelen) { /* @@ -196,16 +243,6 @@ static struct git_attr *git_attr_internal(const char *name, int namelen) attr_hashmap_add(&g_attr_hashmap, a->name, namelen, a); assert(a->attr_nr == (g_attr_hashmap.map.size - 1)); - - /* - * NEEDSWORK: per git_attr_check check_all_attr - * will be initialized a lot more lazily, not - * like this, and not here. - */ - REALLOC_ARRAY(check_all_attr, ++attr_nr); - check_all_attr[a->attr_nr].attr = a; - check_all_attr[a->attr_nr].value = ATTR__UNKNOWN; - assert(a->attr_nr == (attr_nr - 1)); } hashmap_unlock(&g_attr_hashmap); @@ -513,6 +550,10 @@ void attr_check_clear(struct attr_check *check) check->items = NULL; check->alloc = 0; check->nr = 0; + + free(check->all_attrs); + check->all_attrs = NULL; + check->all_attrs_nr = 0; } void attr_check_free(struct attr_check *check) @@ -860,16 +901,16 @@ static int path_matches(const char *pathname, int pathlen, pattern, prefix, pat->patternlen, pat->flags); } -static int macroexpand_one(int attr_nr, int rem); +static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem); -static int fill_one(const char *what, struct match_attr *a, int rem) +static int fill_one(const char *what, struct all_attrs_item *all_attrs, + struct match_attr *a, int rem) { - struct attr_check_item *check = check_all_attr; int i; - for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) { + for (i = a->num_attr - 1; rem > 0 && i >= 0; i--) { struct git_attr *attr = a->state[i].attr; - const char **n = &(check[attr->attr_nr].value); + const char **n = &(all_attrs[attr->attr_nr].value); const char *v = a->state[i].setto; if (*n == ATTR__UNKNOWN) { @@ -878,14 +919,15 @@ static int fill_one(const char *what, struct match_attr *a, int rem) attr, v); *n = v; rem--; - rem = macroexpand_one(attr->attr_nr, rem); + rem = macroexpand_one(all_attrs, attr->attr_nr, rem); } } return rem; } static int fill(const char *path, int pathlen, int basename_offset, - struct attr_stack *stk, int rem) + struct attr_stack *stk, struct all_attrs_item *all_attrs, + int rem) { int i; const char *base = stk->origin ? stk->origin : ""; @@ -896,18 +938,18 @@ static int fill(const char *path, int pathlen, int basename_offset, continue; if (path_matches(path, pathlen, basename_offset, &a->u.pat, base, stk->originlen)) - rem = fill_one("fill", a, rem); + rem = fill_one("fill", all_attrs, a, rem); } return rem; } -static int macroexpand_one(int nr, int rem) +static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem) { struct attr_stack *stk; int i; - if (check_all_attr[nr].value != ATTR__TRUE || - !check_all_attr[nr].attr->maybe_macro) + if (all_attrs[nr].value != ATTR__TRUE || + !all_attrs[nr].attr->maybe_macro) return rem; for (stk = attr_stack; stk; stk = stk->prev) { @@ -916,7 +958,7 @@ static int macroexpand_one(int nr, int rem) if (!ma->is_macro) continue; if (ma->u.attr->attr_nr == nr) - return fill_one("expand", ma, rem); + return fill_one("expand", all_attrs, ma, rem); } } @@ -924,9 +966,9 @@ static int macroexpand_one(int nr, int rem) } /* - * Collect attributes for path into the array pointed to by - * check_all_attr. If num is non-zero, only attributes in check[] are - * collected. Otherwise all attributes are collected. + * Collect attributes for path into the array pointed to by check->all_attrs. + * If check->check_nr is non-zero, only attributes in check[] are collected. + * Otherwise all attributes are collected. */ static void collect_some_attrs(const char *path, struct attr_check *check) { @@ -949,15 +991,15 @@ static void collect_some_attrs(const char *path, struct attr_check *check) } prepare_attr_stack(path, dirlen); - for (i = 0; i < attr_nr; i++) - check_all_attr[i].value = ATTR__UNKNOWN; + all_attrs_init(&g_attr_hashmap, check); + if (check->nr && !cannot_trust_maybe_real) { rem = 0; for (i = 0; i < check->nr; i++) { const struct git_attr *a = check->items[i].attr; if (!a->maybe_real) { - struct attr_check_item *c; - c = check_all_attr + a->attr_nr; + struct all_attrs_item *c; + c = check->all_attrs + a->attr_nr; c->value = ATTR__UNSET; rem++; } @@ -966,9 +1008,9 @@ static void collect_some_attrs(const char *path, struct attr_check *check) return; } - rem = attr_nr; + rem = check->all_attrs_nr; for (stk = attr_stack; 0 < rem && stk; stk = stk->prev) - rem = fill(path, pathlen, basename_offset, stk, rem); + rem = fill(path, pathlen, basename_offset, stk, check->all_attrs, rem); } int git_check_attr(const char *path, struct attr_check *check) @@ -978,7 +1020,8 @@ int git_check_attr(const char *path, struct attr_check *check) collect_some_attrs(path, check); for (i = 0; i < check->nr; i++) { - const char *value = check_all_attr[check->items[i].attr->attr_nr].value; + size_t n = check->items[i].attr->attr_nr; + const char *value = check->all_attrs[n].value; if (value == ATTR__UNKNOWN) value = ATTR__UNSET; check->items[i].value = value; @@ -994,9 +1037,9 @@ void git_all_attrs(const char *path, struct attr_check *check) attr_check_reset(check); collect_some_attrs(path, check); - for (i = 0; i < attr_nr; i++) { - const char *name = check_all_attr[i].attr->name; - const char *value = check_all_attr[i].value; + for (i = 0; i < check->all_attrs_nr; i++) { + const char *name = check->all_attrs[i].attr->name; + const char *value = check->all_attrs[i].value; struct attr_check_item *item; if (value == ATTR__UNSET || value == ATTR__UNKNOWN) continue; -- cgit v1.2.1