details: https://hg.nginx.org/njs/rev/4a543ed58c95
branches:
changeset: 681:4a543ed58c95
user: Valentin Bartenev <vbart@nginx.com>
date: Sat Dec 01 22:32:33 2018 +0300
description:
Slightly optimized njs_object_keys_array().

There is no need to iterate over the object properties second time if after
the first attempt we know that it contains no enumerable properties.

Also removed surplus conditions.

diffstat:

njs/njs_object.c | 19 ++++++++++---------
1 files changed, 10 insertions(+), 9 deletions(-)

diffs (61 lines):

diff -r e713f648ef71 -r 4a543ed58c95 njs/njs_object.c
--- a/njs/njs_object.c Fri Nov 30 17:52:02 2018 +0300
+++ b/njs/njs_object.c Sat Dec 01 22:32:33 2018 +0300
@@ -888,7 +888,7 @@ njs_object_keys(njs_vm_t *vm, njs_value_
njs_array_t *
njs_object_keys_array(njs_vm_t *vm, const njs_value_t *value)
{
- uint32_t i, n, length, keys_length;
+ uint32_t i, n, length, keys_length, properties;
njs_value_t *string;
njs_array_t *keys, *array;
nxt_lvlhsh_t *hash;
@@ -930,15 +930,14 @@ njs_object_keys_array(njs_vm_t *vm, cons
break;
}

+ /* GCC 4 and Clang 3 complain about uninitialized hash. */
+ hash = NULL;
+ properties = 0;
+
if (nxt_fast_path(njs_is_object(value))) {
nxt_lvlhsh_each_init(&lhe, &njs_object_hash_proto);
hash = &value->data.u.object->hash;

- } else {
- hash = NULL;
- }
-
- if (nxt_fast_path(hash != NULL)) {
for ( ;; ) {
prop = nxt_lvlhsh_each(hash, &lhe);

@@ -947,9 +946,11 @@ njs_object_keys_array(njs_vm_t *vm, cons
}

if (prop->type != NJS_WHITEOUT && prop->enumerable) {
- keys_length++;
+ properties++;
}
}
+
+ keys_length += properties;
}

keys = njs_array_alloc(vm, keys_length, NJS_ARRAY_SPARE);
@@ -966,13 +967,13 @@ njs_object_keys_array(njs_vm_t *vm, cons
}
}

- } else if (length != 0) {
+ } else {
for (i = 0; i < length; i++) {
njs_uint32_to_string(&keys->start[n++], i);
}
}

- if (nxt_fast_path(hash != NULL)) {
+ if (nxt_fast_path(properties != 0)) {
nxt_lvlhsh_each_init(&lhe, &njs_object_hash_proto);

for ( ;; ) {
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