MongoDB c驱动程序从bson中提取数组

#include <bson.h>
#include <mongoc.h>

int main() {
    mongoc_init();

    // 创建一个BSON文档
    bson_t *doc = bson_new();
    bson_t *subdoc = bson_new();
    bson_t *array = bson_new_array();

    // 向数组中添加元素
    bson_append_utf8(array, "0", -1, "element1", -1);
    bson_append_utf8(array, "1", -1, "element2", -1);
    bson_append_array(subdoc, "array", -1, array);
    bson_append_document(doc, "subdoc", -1, subdoc);

    // 从BSON中提取数组
    bson_iter_t iter;
    bson_iter_t subiter;

    if (bson_iter_init_find(&iter, doc, "subdoc") &&
        BSON_ITER_HOLDS_DOCUMENT(&iter) &&
        bson_iter_recurse(&iter, &subiter) &&
        bson_iter_find(&subiter, "array") &&
        BSON_ITER_HOLDS_ARRAY(&subiter)) {

        bson_iter_t array_iter;
        bson_iter_recurse(&subiter, &array_iter);

        while (bson_iter_next(&array_iter)) {
            if (BSON_ITER_HOLDS_UTF8(&array_iter)) {
                const char *element = bson_iter_utf8(&array_iter, NULL);
                printf("Array element: %s\n", element);
            }
        }
    }

    // 释放资源
    bson_destroy(doc);
    mongoc_cleanup();

    return 0;
}