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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] libxl: Introduce JSON parser
# HG changeset patch
# User Anthony PERARD <anthony.perard@xxxxxxxxxx>
# Date 1317310104 -3600
# Node ID 5f397994e6d605c4a4d17b7ba86b5ac51c65df8d
# Parent 066dc3758fa46525c5db9f314bc617542f1ea671
libxl: Introduce JSON parser
We use the yajl parser, but we need to make a tree from the parse result
to use it outside the parser.
So this patch include json_object struct that is used to hold the JSON
data.
Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
diff -r 066dc3758fa4 -r 5f397994e6d6 README
--- a/README Thu Sep 29 16:28:23 2011 +0100
+++ b/README Thu Sep 29 16:28:24 2011 +0100
@@ -47,6 +47,7 @@
* Development install of openssl (e.g., openssl-dev)
* Development install of x11 (e.g. xorg-x11-dev)
* Development install of uuid (e.g. uuid-dev)
+ * Development install of yajl (e.g. libyajl-dev)
* bridge-utils package (/sbin/brctl)
* iproute package (/sbin/ip)
* hotplug or udev
diff -r 066dc3758fa4 -r 5f397994e6d6 tools/libxl/Makefile
--- a/tools/libxl/Makefile Thu Sep 29 16:28:23 2011 +0100
+++ b/tools/libxl/Makefile Thu Sep 29 16:28:24 2011 +0100
@@ -32,9 +32,12 @@
LIBXL_OBJS-$(CONFIG_X86) += libxl_cpuid.o
LIBXL_OBJS-$(CONFIG_IA64) += libxl_nocpuid.o
+LIBXL_LIBS += -lyajl
+
LIBXL_OBJS = flexarray.o libxl.o libxl_create.o libxl_dm.o libxl_pci.o \
libxl_dom.o libxl_exec.o libxl_xshelp.o libxl_device.o \
- libxl_internal.o libxl_utils.o libxl_uuid.o
$(LIBXL_OBJS-y)
+ libxl_internal.o libxl_utils.o libxl_uuid.o
libxl_json.o \
+ $(LIBXL_OBJS-y)
LIBXL_OBJS += _libxl_types.o libxl_flask.o _libxl_types_internal.o
$(LIBXL_OBJS): CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest)
$(CFLAGS_libxenstore) $(CFLAGS_libblktapctl)
diff -r 066dc3758fa4 -r 5f397994e6d6 tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h Thu Sep 29 16:28:23 2011 +0100
+++ b/tools/libxl/libxl_internal.h Thu Sep 29 16:28:24 2011 +0100
@@ -394,4 +394,104 @@
#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
+/* from libxl_json */
+#include <yajl/yajl_gen.h>
+
+_hidden yajl_gen_status libxl__yajl_gen_asciiz(yajl_gen hand, const char *str);
+
+typedef enum {
+ JSON_ERROR,
+ JSON_NULL,
+ JSON_TRUE,
+ JSON_FALSE,
+ JSON_INTEGER,
+ JSON_DOUBLE,
+ JSON_STRING,
+ JSON_MAP,
+ JSON_ARRAY,
+ JSON_ANY
+} libxl__json_node_type;
+
+typedef struct libxl__json_object {
+ libxl__json_node_type type;
+ union {
+ long i;
+ double d;
+ char *string;
+ /* List of libxl__json_object */
+ flexarray_t *array;
+ /* List of libxl__json_map_node */
+ flexarray_t *map;
+ } u;
+ struct libxl__json_object *parent;
+} libxl__json_object;
+
+typedef struct {
+ char *map_key;
+ libxl__json_object *obj;
+} libxl__json_map_node;
+
+typedef struct libxl__yajl_ctx libxl__yajl_ctx;
+
+static inline bool libxl__json_object_is_string(const libxl__json_object *o)
+{
+ return o != NULL && o->type == JSON_STRING;
+}
+static inline bool libxl__json_object_is_integer(const libxl__json_object *o)
+{
+ return o != NULL && o->type == JSON_INTEGER;
+}
+static inline bool libxl__json_object_is_map(const libxl__json_object *o)
+{
+ return o != NULL && o->type == JSON_MAP;
+}
+static inline bool libxl__json_object_is_array(const libxl__json_object *o)
+{
+ return o != NULL && o->type == JSON_ARRAY;
+}
+
+static inline
+const char *libxl__json_object_get_string(const libxl__json_object *o)
+{
+ if (libxl__json_object_is_string(o))
+ return o->u.string;
+ else
+ return NULL;
+}
+static inline
+flexarray_t *libxl__json_object_get_map(const libxl__json_object *o)
+{
+ if (libxl__json_object_is_map(o))
+ return o->u.map;
+ else
+ return NULL;
+}
+static inline
+flexarray_t *libxl__json_object_get_array(const libxl__json_object *o)
+{
+ if (libxl__json_object_is_array(o))
+ return o->u.array;
+ else
+ return NULL;
+}
+static inline long libxl__json_object_get_integer(const libxl__json_object *o)
+{
+ if (libxl__json_object_is_integer(o))
+ return o->u.i;
+ else
+ return -1;
+}
+
+_hidden libxl__json_object *libxl__json_array_get(const libxl__json_object *o,
+ int i);
+_hidden
+libxl__json_map_node *libxl__json_map_node_get(const libxl__json_object *o,
+ int i);
+_hidden const libxl__json_object *libxl__json_map_get(const char *key,
+ const libxl__json_object *o,
+ libxl__json_node_type expected_type);
+_hidden void libxl__json_object_free(libxl__gc *gc, libxl__json_object *obj);
+
+_hidden libxl__json_object *libxl__json_parse(libxl__gc *gc, const char *s);
+
#endif
diff -r 066dc3758fa4 -r 5f397994e6d6 tools/libxl/libxl_json.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/libxl/libxl_json.c Thu Sep 29 16:28:24 2011 +0100
@@ -0,0 +1,560 @@
+/*
+ * Copyright (C) 2011 Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include <yajl/yajl_parse.h>
+#include <yajl/yajl_gen.h>
+
+#include "libxl_internal.h"
+
+/* #define DEBUG_ANSWER */
+
+struct libxl__yajl_ctx {
+ libxl__gc *gc;
+ yajl_handle hand;
+ libxl__json_object *head;
+ libxl__json_object *current;
+#ifdef DEBUG_ANSWER
+ yajl_gen g;
+#endif
+};
+
+#ifdef DEBUG_ANSWER
+# define DEBUG_GEN_ALLOC(ctx) \
+ if ((ctx)->g == NULL) { \
+ yajl_gen_config conf = { 1, " " }; \
+ (ctx)->g = yajl_gen_alloc(&conf, NULL); \
+ }
+# define DEBUG_GEN_FREE(ctx) \
+ if ((ctx)->g) yajl_gen_free((ctx)->g)
+# define DEBUG_GEN(ctx, type) yajl_gen_##type(ctx->g)
+# define DEBUG_GEN_VALUE(ctx, type, value) yajl_gen_##type(ctx->g, value)
+# define DEBUG_GEN_STRING(ctx, str, n) yajl_gen_string(ctx->g, str, n)
+# define DEBUG_GEN_REPORT(yajl_ctx) \
+ do { \
+ const unsigned char *buf = NULL; \
+ unsigned int len = 0; \
+ yajl_gen_get_buf((yajl_ctx)->g, &buf, &len); \
+ LIBXL__LOG(libxl__gc_owner((yajl_ctx)->gc), \
+ LIBXL__LOG_DEBUG, "response:\n%s", buf); \
+ yajl_gen_free((yajl_ctx)->g); \
+ (yajl_ctx)->g = NULL; \
+ } while (0)
+#else
+# define DEBUG_GEN_ALLOC(ctx) ((void)0)
+# define DEBUG_GEN_FREE(ctx) ((void)0)
+# define DEBUG_GEN(ctx, type) ((void)0)
+# define DEBUG_GEN_VALUE(ctx, type, value) ((void)0)
+# define DEBUG_GEN_STRING(ctx, value, lenght) ((void)0)
+# define DEBUG_GEN_REPORT(ctx) ((void)0)
+#endif
+
+/*
+ * YAJL Helper
+ */
+
+yajl_gen_status libxl__yajl_gen_asciiz(yajl_gen hand, const char *str)
+{
+ return yajl_gen_string(hand, (const unsigned char *)str, strlen(str));
+}
+
+
+/*
+ * libxl__json_object helper functions
+ */
+
+static libxl__json_object *json_object_alloc(libxl__gc *gc,
+ libxl__json_node_type type)
+{
+ libxl__json_object *obj;
+
+ obj = calloc(1, sizeof (libxl__json_object));
+ if (obj == NULL) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "Failed to allocate a libxl__json_object");
+ return NULL;
+ }
+
+ obj->type = type;
+
+ if (type == JSON_MAP || type == JSON_ARRAY) {
+ flexarray_t *array = flexarray_make(1, 1);
+ if (array == NULL) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "Failed to allocate a flexarray");
+ free(obj);
+ return NULL;
+ }
+ if (type == JSON_MAP)
+ obj->u.map = array;
+ else
+ obj->u.array = array;
+ }
+
+ return obj;
+}
+
+static int json_object_append_to(libxl__gc *gc,
+ libxl__json_object *obj,
+ libxl__json_object *dst)
+{
+ assert(dst != NULL);
+
+ switch (dst->type) {
+ case JSON_MAP: {
+ libxl__json_map_node *last;
+
+ if (dst->u.map->count == 0) {
+ LIBXL__LOG(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "Try to add a value to an empty map (with no key)");
+ return -1;
+ }
+ flexarray_get(dst->u.map, dst->u.map->count - 1, (void**)&last);
+ last->obj = obj;
+ break;
+ }
+ case JSON_ARRAY:
+ if (flexarray_append(dst->u.array, obj) == 2) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "Failed to grow a flexarray");
+ return -1;
+ }
+ break;
+ default:
+ LIBXL__LOG(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "Try append an object is not a map/array (%i)\n",
+ dst->type);
+ return -1;
+ }
+
+ obj->parent = dst;
+ return 0;
+}
+
+void libxl__json_object_free(libxl__gc *gc, libxl__json_object *obj)
+{
+ int index = 0;
+
+ if (obj == NULL)
+ return;
+ switch (obj->type) {
+ case JSON_STRING:
+ free(obj->u.string);
+ break;
+ case JSON_MAP: {
+ libxl__json_map_node *node = NULL;
+
+ for (index = 0; index < obj->u.map->count; index++) {
+ if (flexarray_get(obj->u.map, index, (void**)&node) != 0)
+ break;
+ libxl__json_object_free(gc, node->obj);
+ free(node->map_key);
+ free(node);
+ node = NULL;
+ }
+ flexarray_free(obj->u.map);
+ break;
+ }
+ case JSON_ARRAY: {
+ libxl__json_object *node = NULL;
+ break;
+
+ for (index = 0; index < obj->u.array->count; index++) {
+ if (flexarray_get(obj->u.array, index, (void**)&node) != 0)
+ break;
+ libxl__json_object_free(gc, node);
+ node = NULL;
+ }
+ flexarray_free(obj->u.array);
+ break;
+ }
+ default:
+ break;
+ }
+ free(obj);
+}
+
+libxl__json_object *libxl__json_array_get(const libxl__json_object *o, int i)
+{
+ flexarray_t *array = NULL;
+ libxl__json_object *obj = NULL;
+
+ if ((array = libxl__json_object_get_array(o)) == NULL) {
+ return NULL;
+ }
+
+ if (i >= array->count)
+ return NULL;
+
+ if (flexarray_get(array, i, (void**)&obj) != 0)
+ return NULL;
+
+ return obj;
+}
+
+libxl__json_map_node *libxl__json_map_node_get(const libxl__json_object *o,
+ int i)
+{
+ flexarray_t *array = NULL;
+ libxl__json_map_node *obj = NULL;
+
+ if ((array = libxl__json_object_get_map(o)) == NULL) {
+ return NULL;
+ }
+
+ if (i >= array->count)
+ return NULL;
+
+ if (flexarray_get(array, i, (void**)&obj) != 0)
+ return NULL;
+
+ return obj;
+}
+
+const libxl__json_object *libxl__json_map_get(const char *key,
+ const libxl__json_object *o,
+ libxl__json_node_type expected_type)
+{
+ flexarray_t *maps = NULL;
+ int index = 0;
+
+ if (libxl__json_object_is_map(o)) {
+ libxl__json_map_node *node = NULL;
+
+ maps = o->u.map;
+ for (index = 0; index < maps->count; index++) {
+ if (flexarray_get(maps, index, (void**)&node) != 0)
+ return NULL;
+ if (strcmp(key, node->map_key) == 0) {
+ if (expected_type == JSON_ANY
+ || (node->obj && node->obj->type == expected_type)) {
+ return node->obj;
+ } else {
+ return NULL;
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+
+/*
+ * JSON callbacks
+ */
+
+static int json_callback_null(void *opaque)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj;
+
+ DEBUG_GEN(ctx, null);
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_NULL)) == NULL)
+ return 0;
+
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_boolean(void *opaque, int boolean)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj;
+
+ DEBUG_GEN_VALUE(ctx, bool, boolean);
+
+ if ((obj = json_object_alloc(ctx->gc,
+ boolean ? JSON_TRUE : JSON_FALSE)) == NULL)
+ return 0;
+
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_integer(void *opaque, long value)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj;
+
+ DEBUG_GEN_VALUE(ctx, integer, value);
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_INTEGER)) == NULL)
+ return 0;
+ obj->u.i = value;
+
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_double(void *opaque, double value)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj;
+
+ DEBUG_GEN_VALUE(ctx, double, value);
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_DOUBLE)) == NULL)
+ return 0;
+ obj->u.d = value;
+
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_string(void *opaque, const unsigned char *str,
+ unsigned int len)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ char *t = NULL;
+ libxl__json_object *obj = NULL;
+
+ t = malloc(len + 1);
+ if (t == NULL) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "Failed to allocate");
+ return 0;
+ }
+
+ DEBUG_GEN_STRING(ctx, str, len);
+
+ strncpy(t, (const char *) str, len);
+ t[len] = 0;
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_STRING)) == NULL) {
+ free(t);
+ return 0;
+ }
+ obj->u.string = t;
+
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_map_key(void *opaque, const unsigned char *str,
+ unsigned int len)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ char *t = NULL;
+ libxl__json_object *obj = ctx->current;
+
+ t = malloc(len + 1);
+ if (t == NULL) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "Failed to allocate");
+ return 0;
+ }
+
+ DEBUG_GEN_STRING(ctx, str, len);
+
+ strncpy(t, (const char *) str, len);
+ t[len] = 0;
+
+ if (libxl__json_object_is_map(obj)) {
+ libxl__json_map_node *node = malloc(sizeof (libxl__json_map_node));
+ if (node == NULL) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "Failed to allocate");
+ return 0;
+ }
+
+ node->map_key = t;
+ node->obj = NULL;
+
+ if (flexarray_append(obj->u.map, node) == 2) {
+ LIBXL__LOG_ERRNO(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "Failed to grow a flexarray");
+ return 0;
+ }
+ } else {
+ LIBXL__LOG(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "Current json object is not a map");
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_start_map(void *opaque)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj = NULL;
+
+ DEBUG_GEN(ctx, map_open);
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_MAP)) == NULL)
+ return 0;
+
+ if (ctx->current) {
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+ }
+
+ ctx->current = obj;
+ if (ctx->head == NULL) {
+ ctx->head = obj;
+ }
+
+ return 1;
+}
+
+static int json_callback_end_map(void *opaque)
+{
+ libxl__yajl_ctx *ctx = opaque;
+
+ DEBUG_GEN(ctx, map_close);
+
+ if (ctx->current) {
+ ctx->current = ctx->current->parent;
+ } else {
+ LIBXL__LOG(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "No current libxl__json_object, cannot use his parent.");
+ return 0;
+ }
+
+ return 1;
+}
+
+static int json_callback_start_array(void *opaque)
+{
+ libxl__yajl_ctx *ctx = opaque;
+ libxl__json_object *obj = NULL;
+
+ DEBUG_GEN(ctx, array_open);
+
+ if ((obj = json_object_alloc(ctx->gc, JSON_ARRAY)) == NULL)
+ return 0;
+
+ if (ctx->current) {
+ if (json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+ libxl__json_object_free(ctx->gc, obj);
+ return 0;
+ }
+ }
+
+ ctx->current = obj;
+ if (ctx->head == NULL) {
+ ctx->head = obj;
+ }
+
+ return 1;
+}
+
+static int json_callback_end_array(void *opaque)
+{
+ libxl__yajl_ctx *ctx = opaque;
+
+ DEBUG_GEN(ctx, array_close);
+
+ if (ctx->current) {
+ ctx->current = ctx->current->parent;
+ } else {
+ LIBXL__LOG(libxl__gc_owner(ctx->gc), LIBXL__LOG_ERROR,
+ "No current libxl__json_object, cannot use his parent.");
+ return 0;
+ }
+
+ return 1;
+}
+
+static yajl_callbacks callbacks = {
+ json_callback_null,
+ json_callback_boolean,
+ json_callback_integer,
+ json_callback_double,
+ NULL,
+ json_callback_string,
+ json_callback_start_map,
+ json_callback_map_key,
+ json_callback_end_map,
+ json_callback_start_array,
+ json_callback_end_array
+};
+
+static void yajl_ctx_free(libxl__yajl_ctx *yajl_ctx)
+{
+ if (yajl_ctx->hand) {
+ yajl_free(yajl_ctx->hand);
+ yajl_ctx->hand = NULL;
+ }
+ DEBUG_GEN_FREE(yajl_ctx);
+}
+
+libxl__json_object *libxl__json_parse(libxl__gc *gc, const char *s)
+{
+ yajl_status status;
+ libxl__yajl_ctx yajl_ctx;
+
+ memset(&yajl_ctx, 0, sizeof (yajl_ctx));
+ yajl_ctx.gc = gc;
+
+ DEBUG_GEN_ALLOC(&yajl_ctx);
+
+ if (yajl_ctx.hand == NULL) {
+ yajl_parser_config cfg = {
+ .allowComments = 1,
+ .checkUTF8 = 1,
+ };
+ yajl_ctx.hand = yajl_alloc(&callbacks, &cfg, NULL, &yajl_ctx);
+ }
+ status = yajl_parse(yajl_ctx.hand, (const unsigned char *)s, strlen(s));
+ status = yajl_parse_complete(yajl_ctx.hand);
+
+ if (status == yajl_status_ok) {
+ libxl__json_object *o = yajl_ctx.head;
+
+ DEBUG_GEN_REPORT(&yajl_ctx);
+
+ yajl_ctx.head = NULL;
+
+ yajl_ctx_free(&yajl_ctx);
+ return o;
+ } else {
+ unsigned char *str = yajl_get_error(yajl_ctx.hand, 1,
+ (const unsigned char *)s,
+ strlen(s));
+
+ LIBXL__LOG(libxl__gc_owner(gc), LIBXL__LOG_ERROR,
+ "yajl error: %s", str);
+ yajl_free_error(yajl_ctx.hand, str);
+
+ libxl__json_object_free(gc, yajl_ctx.head);
+ yajl_ctx_free(&yajl_ctx);
+ return NULL;
+ }
+}
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