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Fix hashmap iteration

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When isc_hashmap_iter_delcurrent_next calls hashmap_delete_node
nodes from the front of the table could be added to the end of
the table resulting in them being returned twice.  Detect when
this is happening and prevent those nodes being returned twice
buy reducing the effective size of the table by one each time
it happens.
This commit is contained in:
Mark Andrews
2023-09-19 11:42:03 +10:00
committed by Ondřej Surý
parent c2b6f4357d
commit 92a0d65a51
2 changed files with 43 additions and 22 deletions
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32
tests/isc/hashmap_test.c
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@@ -222,10 +222,11 @@ test_hashmap_iterator(void) {
isc_result_t result;
isc_hashmap_iter_t *iter = NULL;
size_t count = 7600;
uint32_t walked;
test_node_t *nodes;
bool *seen;
nodes = isc_mem_cget(mctx, count, sizeof(nodes[0]));
seen = isc_mem_cget(mctx, count, sizeof(seen[0]));
isc_hashmap_create(mctx, HASHMAP_MIN_BITS, &hashmap);
assert_non_null(hashmap);
@@ -248,7 +249,7 @@ test_hashmap_iterator(void) {
/* We want to iterate while rehashing is in progress */
assert_true(rehashing_in_progress(hashmap));
walked = 0;
memset(seen, 0, count * sizeof(seen[0]));
isc_hashmap_iter_create(hashmap, &iter);
for (result = isc_hashmap_iter_first(iter); result == ISC_R_SUCCESS;
@@ -269,13 +270,16 @@ test_hashmap_iterator(void) {
assert_memory_equal(key, tkey, 16);
walked++;
assert_false(seen[i]);
seen[i] = true;
}
assert_int_equal(walked, count);
assert_int_equal(result, ISC_R_NOMORE);
for (size_t i = 0; i < count; i++) {
assert_true(seen[i]);
}
/* erase odd */
walked = 0;
memset(seen, 0, count * sizeof(seen[0]));
result = isc_hashmap_iter_first(iter);
while (result == ISC_R_SUCCESS) {
char key[16] = { 0 };
@@ -296,13 +300,17 @@ test_hashmap_iterator(void) {
} else {
result = isc_hashmap_iter_next(iter);
}
walked++;
assert_false(seen[i]);
seen[i] = true;
}
assert_int_equal(result, ISC_R_NOMORE);
assert_int_equal(walked, count);
for (size_t i = 0; i < count; i++) {
assert_true(seen[i]);
}
/* erase even */
walked = 0;
memset(seen, 0, count * sizeof(seen[0]));
result = isc_hashmap_iter_first(iter);
while (result == ISC_R_SUCCESS) {
char key[16] = { 0 };
@@ -323,20 +331,15 @@ test_hashmap_iterator(void) {
} else {
result = isc_hashmap_iter_next(iter);
}
walked++;
}
assert_int_equal(result, ISC_R_NOMORE);
assert_int_equal(walked, count / 2);
walked = 0;
for (result = isc_hashmap_iter_first(iter); result == ISC_R_SUCCESS;
result = isc_hashmap_iter_next(iter))
{
walked++;
assert_true(false);
}
assert_int_equal(result, ISC_R_NOMORE);
assert_int_equal(walked, 0);
/* Iterator doesn't progress rehashing */
assert_true(rehashing_in_progress(hashmap));
@@ -347,6 +350,7 @@ test_hashmap_iterator(void) {
isc_hashmap_destroy(&hashmap);
assert_null(hashmap);
isc_mem_cput(mctx, seen, count, sizeof(seen[0]));
isc_mem_cput(mctx, nodes, count, sizeof(nodes[0]));
}