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 <bmw...@google.com>
---
attr.c | 121 ++++++++++++++++++++++++++++++++++++++++++++---------------------
attr.h | 5 +++
2 files changed, 87 insertions(+), 39 deletions(-)
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;
diff --git a/attr.h b/attr.h
index 898e1a8c9..5aaf55c3e 100644
--- a/attr.h
+++ b/attr.h
@@ -4,6 +4,9 @@
/* An attribute is a pointer to this opaque structure */
struct git_attr;
+/* opaque structure used internally for attribute collection */
+struct all_attrs_item;
+
/*
* Given a string, return the gitattribute object that
* corresponds to it.
@@ -33,6 +36,8 @@ struct attr_check {
int nr;
int alloc;
struct attr_check_item *items;
+ int all_attrs_nr;
+ struct all_attrs_item *all_attrs;
};
extern struct attr_check *attr_check_alloc(void);
--
2.11.0.483.g087da7b7c-goog
