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json: Use functions to access json arrays.
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Internal implementation of JSON array will be changed in the future
commits.  Add access functions that users can rely on instead of
accessing the internals of 'struct json' directly and convert all the
users.  Structure fields are intentionally renamed to make sure that
no code is using the old fields directly.

json_array() function is removed, as not needed anymore.  Added new
functions:  json_array_size(), json_array_at(), json_array_set()
and json_array_pop().  These are enough to cover all the use cases
within OVS.

The change is fairly large, however, IMO, it's a much overdue cleanup
that we need even without changing the underlying implementation.

Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
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@igsilya
igsilya committed Dec 17, 2024
1 parent 5f545e6 commit 1665537
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Showing 24 changed files with 485 additions and 411 deletions.
9 changes: 6 additions & 3 deletions include/openvswitch/json.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,8 @@ const char *json_type_to_string(enum json_type);

/* A JSON array. */
struct json_array {
size_t n, n_allocated;
struct json **elems;
size_t size, allocated;
struct json **elements;
};

/* Maximum string length that can be stored inline ('\0' is not included). */
Expand Down Expand Up @@ -98,6 +98,8 @@ struct json *json_real_create(double);

struct json *json_array_create_empty(void);
void json_array_add(struct json *, struct json *element);
void json_array_set(struct json *, size_t index, struct json *element);
struct json *json_array_pop(struct json *);
void json_array_trim(struct json *);
struct json *json_array_create(struct json **, size_t n);
struct json *json_array_create_1(struct json *);
Expand All @@ -116,7 +118,8 @@ void json_object_put_format(struct json *,

const char *json_string(const struct json *);
const char *json_serialized_object(const struct json *);
struct json_array *json_array(const struct json *);
size_t json_array_size(const struct json *);
const struct json *json_array_at(const struct json *, size_t index);
struct shash *json_object(const struct json *);
bool json_boolean(const struct json *);
double json_real(const struct json *);
Expand Down
181 changes: 111 additions & 70 deletions lib/json.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -221,77 +221,93 @@ struct json *
json_array_create_empty(void)
{
struct json *json = json_create(JSON_ARRAY);
json->array.elems = NULL;
json->array.n = 0;
json->array.n_allocated = 0;
json->array.elements = NULL;
json->array.size = 0;
json->array.allocated = 0;
return json;
}

void
json_array_add(struct json *array_, struct json *element)
{
struct json_array *array = json_array(array_);
if (array->n >= array->n_allocated) {
array->elems = x2nrealloc(array->elems, &array->n_allocated,
sizeof *array->elems);
struct json_array *array = &array_->array;
if (array->size >= array->allocated) {
array->elements = x2nrealloc(array->elements, &array->allocated,
sizeof *array->elements);
}
array->elems[array->n++] = element;
array->elements[array->size++] = element;
}

void
json_array_set(struct json *json, size_t index, struct json *element)
{
ovs_assert(json_array_size(json) > index);
json->array.elements[index] = element;
}

struct json *
json_array_pop(struct json *json)
{
size_t n = json_array_size(json);

return n ? json->array.elements[--n] : NULL;
}

void
json_array_trim(struct json *array_)
{
struct json_array *array = json_array(array_);
if (array->n < array->n_allocated){
array->n_allocated = array->n;
array->elems = xrealloc(array->elems, array->n * sizeof *array->elems);
struct json_array *array = &array_->array;
if (array->size < array->allocated) {
array->allocated = array->size;
array->elements = xrealloc(array->elements,
array->size * sizeof *array->elements);
}
}

struct json *
json_array_create(struct json **elements, size_t n)
{
struct json *json = json_create(JSON_ARRAY);
json->array.elems = elements;
json->array.n = n;
json->array.n_allocated = n;
json->array.elements = elements;
json->array.size = n;
json->array.allocated = n;
return json;
}

struct json *
json_array_create_1(struct json *elem0)
{
struct json **elems = xmalloc(sizeof *elems);
elems[0] = elem0;
return json_array_create(elems, 1);
struct json **elements = xmalloc(sizeof *elements);
elements[0] = elem0;
return json_array_create(elements, 1);
}

struct json *
json_array_create_2(struct json *elem0, struct json *elem1)
{
struct json **elems = xmalloc(2 * sizeof *elems);
elems[0] = elem0;
elems[1] = elem1;
return json_array_create(elems, 2);
struct json **elements = xmalloc(2 * sizeof *elements);
elements[0] = elem0;
elements[1] = elem1;
return json_array_create(elements, 2);
}

struct json *
json_array_create_3(struct json *elem0, struct json *elem1, struct json *elem2)
{
struct json **elems = xmalloc(3 * sizeof *elems);
elems[0] = elem0;
elems[1] = elem1;
elems[2] = elem2;
return json_array_create(elems, 3);
struct json **elements = xmalloc(3 * sizeof *elements);
elements[0] = elem0;
elements[1] = elem1;
elements[2] = elem2;
return json_array_create(elements, 3);
}

bool
json_array_contains_string(const struct json *json, const char *str)
{
ovs_assert(json->type == JSON_ARRAY);
size_t n = json_array_size(json);

for (size_t i = 0; i < json->array.n; i++) {
const struct json *elem = json->array.elems[i];
for (size_t i = 0; i < n; i++) {
const struct json *elem = json_array_at(json, i);

if (elem->type == JSON_STRING && !strcmp(json_string(elem), str)) {
return true;
Expand Down Expand Up @@ -370,11 +386,18 @@ json_serialized_object(const struct json *json)
return json->str_ptr;
}

struct json_array *
json_array(const struct json *json)
size_t
json_array_size(const struct json *json)
{
ovs_assert(json->type == JSON_ARRAY);
return json->array.size;
}

const struct json *
json_array_at(const struct json *json, size_t index)
{
ovs_assert(json->type == JSON_ARRAY);
return CONST_CAST(struct json_array *, &json->array);
return (json->array.size > index) ? json->array.elements[index] : NULL;
}

struct shash *
Expand Down Expand Up @@ -406,7 +429,7 @@ json_integer(const struct json *json)
}

static void json_destroy_object(struct shash *object, bool yield);
static void json_destroy_array(struct json_array *array, bool yield);
static void json_destroy_array(struct json *json, bool yield);

/* Frees 'json' and everything it points to, recursively. */
void
Expand All @@ -418,7 +441,7 @@ json_destroy__(struct json *json, bool yield)
break;

case JSON_ARRAY:
json_destroy_array(&json->array, yield);
json_destroy_array(json, yield);
break;

case JSON_STRING:
Expand Down Expand Up @@ -468,26 +491,27 @@ json_destroy_object(struct shash *object, bool yield)
}

static void
json_destroy_array(struct json_array *array, bool yield)
json_destroy_array(struct json *json, bool yield)
{
size_t i;
size_t i, n = json_array_size(json);

if (yield) {
cooperative_multitasking_yield();
}

for (i = 0; i < array->n; i++) {
for (i = 0; i < n; i++) {
if (yield) {
json_destroy_with_yield(array->elems[i]);
json_destroy_with_yield(
CONST_CAST(struct json *, json_array_at(json, i)));
} else {
json_destroy(array->elems[i]);
json_destroy(CONST_CAST(struct json *, json_array_at(json, i)));
}
}
free(array->elems);
free(json->array.elements);
}

static struct json *json_deep_clone_object(const struct shash *object);
static struct json *json_deep_clone_array(const struct json_array *array);
static struct json *json_deep_clone_array(const struct json *);

/* Returns a deep copy of 'json'. */
struct json *
Expand All @@ -498,7 +522,7 @@ json_deep_clone(const struct json *json)
return json_deep_clone_object(json->object);

case JSON_ARRAY:
return json_deep_clone_array(&json->array);
return json_deep_clone_array(json);

case JSON_STRING:
return json_string_create(json_string(json));
Expand Down Expand Up @@ -544,16 +568,33 @@ json_deep_clone_object(const struct shash *object)
}

static struct json *
json_deep_clone_array(const struct json_array *array)
{
struct json **elems;
size_t i;
json_deep_clone_array(const struct json *json)
{
struct json **elements;
size_t i, n;

n = json_array_size(json);
switch (n) {
case 0:
return json_array_create_empty();
case 1:
return json_array_create_1(json_deep_clone(json_array_at(json, 0)));
case 2:
return json_array_create_2(json_deep_clone(json_array_at(json, 0)),
json_deep_clone(json_array_at(json, 1)));
case 3:
return json_array_create_3(json_deep_clone(json_array_at(json, 0)),
json_deep_clone(json_array_at(json, 1)),
json_deep_clone(json_array_at(json, 2)));
default:
break;
}

elems = xmalloc(array->n * sizeof *elems);
for (i = 0; i < array->n; i++) {
elems[i] = json_deep_clone(array->elems[i]);
elements = xmalloc(n * sizeof *elements);
for (i = 0; i < n; i++) {
elements[i] = json_deep_clone(json_array_at(json, i));
}
return json_array_create(elems, array->n);
return json_array_create(elements, n);
}

static size_t
Expand All @@ -574,13 +615,13 @@ json_hash_object(const struct shash *object, size_t basis)
}

static size_t
json_hash_array(const struct json_array *array, size_t basis)
json_hash_array(const struct json *json, size_t basis)
{
size_t i;
size_t i, n = json_array_size(json);

basis = hash_int(array->n, basis);
for (i = 0; i < array->n; i++) {
basis = json_hash(array->elems[i], basis);
basis = hash_int(n, basis);
for (i = 0; i < n; i++) {
basis = json_hash(json_array_at(json, i), basis);
}
return basis;
}
Expand All @@ -593,7 +634,7 @@ json_hash(const struct json *json, size_t basis)
return json_hash_object(json->object, basis);

case JSON_ARRAY:
return json_hash_array(&json->array, basis);
return json_hash_array(json, basis);

case JSON_STRING:
return hash_string(json_string(json), basis);
Expand Down Expand Up @@ -638,16 +679,16 @@ json_equal_object(const struct shash *a, const struct shash *b)
}

static bool
json_equal_array(const struct json_array *a, const struct json_array *b)
json_equal_array(const struct json *a, const struct json *b)
{
size_t i;
size_t i, n = json_array_size(a);

if (a->n != b->n) {
if (n != json_array_size(b)) {
return false;
}

for (i = 0; i < a->n; i++) {
if (!json_equal(a->elems[i], b->elems[i])) {
for (i = 0; i < n; i++) {
if (!json_equal(json_array_at(a, i), json_array_at(b, i))) {
return false;
}
}
Expand All @@ -671,7 +712,7 @@ json_equal(const struct json *a, const struct json *b)
return json_equal_object(a->object, b->object);

case JSON_ARRAY:
return json_equal_array(&a->array, &b->array);
return json_equal_array(a, b);

case JSON_STRING:
return !strcmp(json_string(a), json_string(b));
Expand Down Expand Up @@ -1594,7 +1635,7 @@ struct json_serializer {
static void json_serialize(const struct json *, struct json_serializer *);
static void json_serialize_object(const struct shash *object,
struct json_serializer *);
static void json_serialize_array(const struct json_array *,
static void json_serialize_array(const struct json *,
struct json_serializer *);
static void json_serialize_string(const char *, struct ds *);

Expand Down Expand Up @@ -1657,7 +1698,7 @@ json_serialize(const struct json *json, struct json_serializer *s)
break;

case JSON_ARRAY:
json_serialize_array(&json->array, s);
json_serialize_array(json, s);
break;

case JSON_INTEGER:
Expand Down Expand Up @@ -1749,10 +1790,10 @@ json_serialize_object(const struct shash *object, struct json_serializer *s)
}

static void
json_serialize_array(const struct json_array *array, struct json_serializer *s)
json_serialize_array(const struct json *json, struct json_serializer *s)
{
size_t i, n = json_array_size(json);
struct ds *ds = s->ds;
size_t i;

ds_put_char(ds, '[');
s->depth++;
Expand All @@ -1761,15 +1802,15 @@ json_serialize_array(const struct json_array *array, struct json_serializer *s)
cooperative_multitasking_yield();
}

if (array->n > 0) {
if (n > 0) {
indent_line(s);

for (i = 0; i < array->n; i++) {
for (i = 0; i < n; i++) {
if (i) {
ds_put_char(ds, ',');
indent_line(s);
}
json_serialize(array->elems[i], s);
json_serialize(json_array_at(json, i), s);
}
}

Expand Down
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