NAME

       bson_visitor_t  -  The bson_visitor_t structure provides a series of callbacks that can be
       called while iterating a BSON document. This may simplify the conversion of a bson_t to  a
       higher level language structure.

SYNOPSIS

       #include <bson.h>

       typedef struct
       {
          bool (*visit_before)     (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);
          bool (*visit_after)      (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);
          void (*visit_corrupt)    (const bson_iter_t *iter,
                                    void              *data);
          bool (*visit_double)     (const bson_iter_t *iter,
                                    const char        *key,
                                    double             v_double,
                                    void              *data);
          bool (*visit_utf8)       (const bson_iter_t *iter,
                                    const char        *key,
                                    size_t             v_utf8_len,
                                    const char        *v_utf8,
                                    void              *data);
          bool (*visit_document)   (const bson_iter_t *iter,
                                    const char        *key,
                                    const bson_t      *v_document,
                                    void              *data);
          bool (*visit_array)      (const bson_iter_t *iter,
                                    const char        *key,
                                    const bson_t      *v_array,
                                    void              *data);
          bool (*visit_binary)     (const bson_iter_t *iter,
                                    const char        *key,
                                    bson_subtype_t     v_subtype,
                                    size_t             v_binary_len,
                                    const uint8_t     *v_binary,
                                    void              *data);
          bool (*visit_undefined)  (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);
          bool (*visit_oid)        (const bson_iter_t *iter,
                                    const char        *key,
                                    const bson_oid_t  *v_oid,
                                    void              *data);
          bool (*visit_bool)       (const bson_iter_t *iter,
                                    const char        *key,
                                    bool               v_bool,
                                    void              *data);
          bool (*visit_date_time)  (const bson_iter_t *iter,
                                    const char        *key,
                                    int64_t            msec_since_epoch,
                                    void              *data);
          bool (*visit_null)       (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);
          bool (*visit_regex)      (const bson_iter_t *iter,
                                    const char        *key,
                                    const char        *v_regex,
                                    const char        *v_options,
                                    void              *data);
          bool (*visit_dbpointer)  (const bson_iter_t *iter,
                                    const char        *key,
                                    size_t             v_collection_len,
                                    const char        *v_collection,
                                    const bson_oid_t  *v_oid,
                                    void              *data);
          bool (*visit_code)       (const bson_iter_t *iter,
                                    const char        *key,
                                    size_t             v_code_len,
                                    const char        *v_code,
                                    void              *data);
          bool (*visit_symbol)     (const bson_iter_t *iter,
                                    const char        *key,
                                    size_t             v_symbol_len,
                                    const char        *v_symbol,
                                    void              *data);
          bool (*visit_codewscope) (const bson_iter_t *iter,
                                    const char        *key,
                                    size_t             v_code_len,
                                    const char        *v_code,
                                    const bson_t      *v_scope,
                                    void              *data);
          bool (*visit_int32)      (const bson_iter_t *iter,
                                    const char        *key,
                                    int32_t            v_int32,
                                    void              *data);
          bool (*visit_timestamp)  (const bson_iter_t *iter,
                                    const char        *key,
                                    uint32_t           v_timestamp,
                                    uint32_t           v_increment,
                                    void              *data);
          bool (*visit_int64)      (const bson_iter_t *iter,
                                    const char        *key,
                                    int64_t            v_int64,
                                    void              *data);
          bool (*visit_maxkey)     (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);
          bool (*visit_minkey)     (const bson_iter_t *iter,
                                    const char        *key,
                                    void              *data);

          void *padding[9];
       } bson_visitor_t;

DESCRIPTION

       The  bson_visitor_t  structure  provides  a  series  of callbacks that can be called while
       iterating a BSON document. This may simplify the conversion of a bson_t to a higher  level
       language structure.

EXAMPLE

       #include <bson.h>
       #include <stdio.h>

       static bool
       my_visit_before (const bson_iter_t *iter,
                        const char        *key,
                        void              *data)
       {
          int *count = (int *)data;

          (*count)++;

          /* returning true stops further iteration of the document */

          return false;
       }

       static void
       count_fields (bson_t *doc)
       {
          bson_visitor_t visitor;
          bson_iter_t iter;
          int count = 0;

          visitor.visit_before = my_visit_before;

          if (bson_iter_init (&iter, doc)) {
             bson_iter_visit_all (&iter, &visitor, &count);
          }

          printf ("Found %d fields.\n", count);
       }

COLOPHON

       This     page     is     part     of    libbson.     Please    report    any    bugs    at
       https://jira.mongodb.org/browse/CDRIVER.