[systemd-devel] [PATCH v2 2/5] shared/json: Added DOM-like JSON parser
Pavel Odvody
podvody at redhat.com
Tue May 19 07:29:42 PDT 2015
This makes working with complexly structured documents easy
and more reliable as the parser is not susceptible to
element re-ordering.
Also fixes a bug when the tokenizer would choke after reading
a number.
---
src/shared/json.c | 432 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
src/shared/json.h | 37 +++++
2 files changed, 459 insertions(+), 10 deletions(-)
diff --git a/src/shared/json.c b/src/shared/json.c
index 45c8ece..f6c44f4 100644
--- a/src/shared/json.c
+++ b/src/shared/json.c
@@ -21,17 +21,171 @@
#include <sys/types.h>
#include <math.h>
-
#include "macro.h"
-#include "util.h"
#include "utf8.h"
#include "json.h"
-enum {
- STATE_NULL,
- STATE_VALUE,
- STATE_VALUE_POST,
-};
+int json_variant_new(JsonVariant **ret, JsonVariantType type) {
+ JsonVariant *v;
+ v = new0(JsonVariant, 1);
+ if (!v)
+ return -ENOMEM;
+ v->type = type;
+ *ret = v;
+ return 0;
+}
+
+static int json_variant_deep_copy(JsonVariant *ret, JsonVariant *variant) {
+ assert(ret);
+ assert(variant);
+
+ ret->type = variant->type;
+ ret->size = variant->size;
+
+ if (variant->type == JSON_VARIANT_STRING) {
+ ret->string = memdup(variant->string, variant->size+1);
+ if (!ret->string)
+ return -ENOMEM;
+ } else if (variant->type == JSON_VARIANT_ARRAY || variant->type == JSON_VARIANT_OBJECT) {
+ ret->objects = new0(JsonVariant, variant->size);
+ if (!ret->objects)
+ return -ENOMEM;
+
+ for (unsigned i = 0; i < variant->size; ++i) {
+ int r;
+ r = json_variant_deep_copy(&ret->objects[i], &variant->objects[i]);
+ if (r < 0)
+ return r;
+ }
+ }
+ else
+ ret->value = variant->value;
+
+ return 0;
+}
+
+static JsonVariant *json_object_unref(JsonVariant *variant);
+
+static JsonVariant *json_variant_unref_inner(JsonVariant *variant) {
+ if (!variant)
+ return NULL;
+
+ if (variant->type == JSON_VARIANT_ARRAY || variant->type == JSON_VARIANT_OBJECT)
+ return json_object_unref(variant);
+
+ else if (variant->type == JSON_VARIANT_STRING)
+ free(variant->string);
+
+ return NULL;
+}
+
+static JsonVariant *json_raw_unref(JsonVariant *variant, size_t size) {
+ if (!variant)
+ return NULL;
+
+ for (size_t i = 0; i < size; ++i)
+ json_variant_unref_inner(&variant[i]);
+
+ free(variant);
+ return NULL;
+}
+
+static JsonVariant *json_object_unref(JsonVariant *variant) {
+ assert(variant);
+ if (!variant->objects)
+ return NULL;
+
+ for (unsigned i = 0; i < variant->size; ++i)
+ json_variant_unref_inner(&variant->objects[i]);
+
+ free(variant->objects);
+ return NULL;
+}
+
+static JsonVariant **json_variant_array_unref(JsonVariant **variant) {
+ size_t i = 0;
+ JsonVariant *p = NULL;
+
+ if (!variant)
+ return NULL;
+
+ while((p = (variant[i++])) != NULL) {
+ if (p->type == JSON_VARIANT_STRING)
+ free(p->string);
+ free(p);
+ }
+
+ free(variant);
+
+ return NULL;
+}
+DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant **, json_variant_array_unref);
+
+JsonVariant *json_variant_unref(JsonVariant *variant) {
+ if (!variant)
+ return NULL;
+
+ if (variant->type == JSON_VARIANT_ARRAY || variant->type == JSON_VARIANT_OBJECT)
+ return json_object_unref(variant);
+
+ else if (variant->type == JSON_VARIANT_STRING)
+ free(variant->string);
+
+ free(variant);
+
+ return NULL;
+}
+
+char *json_variant_string(JsonVariant *variant){
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_STRING);
+
+ return variant->string;
+}
+
+bool json_variant_bool(JsonVariant *variant) {
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_BOOLEAN);
+
+ return variant->value.boolean;
+}
+
+intmax_t json_variant_integer(JsonVariant *variant) {
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_INTEGER);
+
+ return variant->value.integer;
+}
+
+double json_variant_real(JsonVariant *variant) {
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_REAL);
+
+ return variant->value.real;
+}
+
+JsonVariant *json_variant_element(JsonVariant *variant, unsigned index) {
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_ARRAY || variant->type == JSON_VARIANT_OBJECT);
+ assert(index < variant->size);
+ assert(variant->objects);
+
+ return &variant->objects[index];
+}
+
+JsonVariant *json_variant_value(JsonVariant *variant, const char *key) {
+ assert(variant);
+ assert(variant->type == JSON_VARIANT_OBJECT);
+ assert(variant->objects);
+
+ for (unsigned i = 0; i < variant->size; i += 2) {
+ JsonVariant *p = &variant->objects[i];
+ if (p->type == JSON_VARIANT_STRING && streq(key, p->string))
+ return &variant->objects[i + 1];
+ }
+
+ return NULL;
+}
static void inc_lines(unsigned *line, const char *s, size_t n) {
const char *p = s;
@@ -285,9 +439,6 @@ static int json_parse_number(const char **p, union json_value *ret) {
} while (strchr("0123456789", *c) && *c != 0);
}
- if (*c != 0)
- return -EINVAL;
-
*p = c;
if (is_double) {
@@ -310,6 +461,12 @@ int json_tokenize(
int t;
int r;
+ enum {
+ STATE_NULL,
+ STATE_VALUE,
+ STATE_VALUE_POST,
+ };
+
assert(p);
assert(*p);
assert(ret_string);
@@ -443,3 +600,258 @@ int json_tokenize(
}
}
+
+static bool json_is_value(JsonVariant *var) {
+ assert(var);
+
+ return var->type != JSON_VARIANT_CONTROL;
+}
+
+static int json_scoped_parse(JsonVariant **tokens, size_t *i, size_t n, JsonVariant *scope) {
+ bool arr = scope->type == JSON_VARIANT_ARRAY;
+ int terminator = arr ? JSON_ARRAY_CLOSE : JSON_OBJECT_CLOSE;
+ size_t allocated = 0, size = 0;
+ JsonVariant *key = NULL, *value = NULL, *var = NULL, *items = NULL;
+ enum {
+ STATE_KEY,
+ STATE_COLON,
+ STATE_COMMA,
+ STATE_VALUE
+ } state = arr ? STATE_VALUE : STATE_KEY;
+
+ assert(tokens);
+ assert(i);
+ assert(scope);
+
+ while((var = *i < n ? tokens[(*i)++] : NULL) != NULL) {
+ bool stopper = !json_is_value(var) && var->value.integer == terminator;
+ int r;
+
+ if (stopper) {
+ if (state != STATE_COMMA && size > 0)
+ goto error;
+
+ goto out;
+ }
+
+ if (state == STATE_KEY) {
+ if (var->type != JSON_VARIANT_STRING)
+ goto error;
+ else {
+ key = var;
+ state = STATE_COLON;
+ }
+ }
+ else if (state == STATE_COLON) {
+ if (key == NULL)
+ goto error;
+
+ if (json_is_value(var))
+ goto error;
+
+ if (var->value.integer != JSON_COLON)
+ goto error;
+
+ state = STATE_VALUE;
+ }
+ else if (state == STATE_VALUE) {
+ _cleanup_jsonunref_ JsonVariant *v = NULL;
+ size_t toadd = arr ? 1 : 2;
+
+ if (!json_is_value(var)) {
+ int type = (var->value.integer == JSON_ARRAY_OPEN) ? JSON_VARIANT_ARRAY : JSON_VARIANT_OBJECT;
+
+ r = json_variant_new(&v, type);
+ if (r < 0)
+ goto error;
+
+ r = json_scoped_parse(tokens, i, n, v);
+ if (r < 0)
+ goto error;
+
+ value = v;
+ }
+ else
+ value = var;
+
+ if(!GREEDY_REALLOC(items, allocated, size + toadd))
+ goto error;
+
+ if (arr) {
+ r = json_variant_deep_copy(&items[size], value);
+ if (r < 0)
+ goto error;
+ } else {
+ r = json_variant_deep_copy(&items[size], key);
+ if (r < 0)
+ goto error;
+
+ r = json_variant_deep_copy(&items[size+1], value);
+ if (r < 0)
+ goto error;
+ }
+
+ size += toadd;
+ state = STATE_COMMA;
+ }
+ else if (state == STATE_COMMA) {
+ if (json_is_value(var))
+ goto error;
+
+ if (var->value.integer != JSON_COMMA)
+ goto error;
+
+ key = NULL;
+ value = NULL;
+
+ state = arr ? STATE_VALUE : STATE_KEY;
+ }
+ }
+
+error:
+ json_raw_unref(items, size);
+ return -EBADMSG;
+
+out:
+ scope->size = size;
+ scope->objects = items;
+
+ return scope->type;
+}
+
+static int json_parse_tokens(JsonVariant **tokens, size_t ntokens, JsonVariant **rv) {
+ size_t it = 0;
+ int r;
+ JsonVariant *e;
+ _cleanup_jsonunref_ JsonVariant *p;
+
+ assert(tokens);
+ assert(ntokens);
+
+ e = tokens[it++];
+ r = json_variant_new(&p, JSON_VARIANT_OBJECT);
+ if (r < 0)
+ return r;
+
+ if (e->type != JSON_VARIANT_CONTROL && e->value.integer != JSON_OBJECT_OPEN)
+ return -EBADMSG;
+
+ r = json_scoped_parse(tokens, &it, ntokens, p);
+ if (r < 0)
+ return r;
+
+ *rv = p;
+ p = NULL;
+
+ return 0;
+}
+
+static int json_tokens(const char *string, size_t size, JsonVariant ***tokens, size_t *n) {
+ _cleanup_free_ char *buf = NULL;
+ _cleanup_(json_variant_array_unrefp) JsonVariant **items = NULL;
+ union json_value v = {};
+ void *json_state = NULL;
+ const char *p;
+ int t, r;
+ size_t allocated = 0, s = 0;
+
+ assert(string);
+ assert(n);
+
+ if (size <= 0)
+ return -EBADMSG;
+
+ buf = strndup(string, size);
+ if (!buf)
+ return -ENOMEM;
+
+ p = buf;
+ for (;;) {
+ _cleanup_free_ char *rstr = NULL;
+ _cleanup_jsonunref_ JsonVariant *var = NULL;
+
+ t = json_tokenize(&p, &rstr, &v, &json_state, NULL);
+
+ if (t < 0)
+ return t;
+ else if (t == JSON_END)
+ break;
+
+ if (t <= JSON_ARRAY_CLOSE) {
+ r = json_variant_new(&var, JSON_VARIANT_CONTROL);
+ if (r < 0)
+ return r;
+ var->value.integer = t;
+ } else {
+ switch (t) {
+ case JSON_STRING:
+ r = json_variant_new(&var, JSON_VARIANT_STRING);
+ if (r < 0)
+ return r;
+ var->size = strlen(rstr);
+ var->string = strdup(rstr);
+ if (!var->string) {
+ return -ENOMEM;
+ }
+ break;
+ case JSON_INTEGER:
+ r = json_variant_new(&var, JSON_VARIANT_INTEGER);
+ if (r < 0)
+ return r;
+ var->value = v;
+ break;
+ case JSON_REAL:
+ r = json_variant_new(&var, JSON_VARIANT_REAL);
+ if (r < 0)
+ return r;
+ var->value = v;
+ break;
+ case JSON_BOOLEAN:
+ r = json_variant_new(&var, JSON_VARIANT_BOOLEAN);
+ if (r < 0)
+ return r;
+ var->value = v;
+ break;
+ case JSON_NULL:
+ r = json_variant_new(&var, JSON_VARIANT_NULL);
+ if (r < 0)
+ return r;
+ break;
+ }
+ }
+
+ if (!GREEDY_REALLOC(items, allocated, s+2))
+ return -ENOMEM;
+
+ items[s++] = var;
+ items[s] = NULL;
+ var = NULL;
+ }
+
+ *n = s;
+ *tokens = items;
+ items = NULL;
+
+ return 0;
+}
+
+int json_parse(const char *string, JsonVariant **rv) {
+ _cleanup_(json_variant_array_unrefp) JsonVariant **s = NULL;
+ JsonVariant *v = NULL;
+ size_t n = 0;
+ int r;
+
+ assert(string);
+ assert(rv);
+
+ r = json_tokens(string, strlen(string), &s, &n);
+ if (r < 0)
+ return r;
+
+ r = json_parse_tokens(s, n, &v);
+ if (r < 0)
+ return r;
+
+ *rv = v;
+ return 0;
+}
diff --git a/src/shared/json.h b/src/shared/json.h
index 55976d5..2ce5642 100644
--- a/src/shared/json.h
+++ b/src/shared/json.h
@@ -22,6 +22,7 @@
***/
#include <stdbool.h>
+#include "util.h"
enum {
JSON_END,
@@ -38,12 +39,48 @@ enum {
JSON_NULL,
};
+typedef enum {
+ JSON_VARIANT_CONTROL,
+ JSON_VARIANT_STRING,
+ JSON_VARIANT_INTEGER,
+ JSON_VARIANT_BOOLEAN,
+ JSON_VARIANT_REAL,
+ JSON_VARIANT_ARRAY,
+ JSON_VARIANT_OBJECT,
+ JSON_VARIANT_NULL
+} JsonVariantType;
+
union json_value {
bool boolean;
double real;
intmax_t integer;
};
+typedef struct JsonVariant {
+ union {
+ char *string;
+ struct JsonVariant *objects;
+ union json_value value;
+ };
+ JsonVariantType type;
+ unsigned size;
+} JsonVariant;
+
+int json_variant_new(JsonVariant **ret, JsonVariantType type);
+JsonVariant *json_variant_unref(JsonVariant *);
+DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant *, json_variant_unref);
+#define _cleanup_jsonunref_ _cleanup_(json_variant_unrefp)
+
+char *json_variant_string(JsonVariant *);
+bool json_variant_bool(JsonVariant *);
+intmax_t json_variant_integer(JsonVariant *);
+double json_variant_real(JsonVariant *);
+
+JsonVariant *json_variant_element(JsonVariant *, unsigned index);
+JsonVariant *json_variant_value(JsonVariant *, const char *key);
+
#define JSON_VALUE_NULL ((union json_value) {})
int json_tokenize(const char **p, char **ret_string, union json_value *ret_value, void **state, unsigned *line);
+int json_parse(const char *string, JsonVariant **rv);
+int json_parse_measure(const char *string, size_t *size);
--
2.1.0
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