"distinct" e "mapReduce"

bool
distinct (mongoc_database_t *database)
{
   bson_t *command;
   bson_t reply;
   bson_error_t error;
   bool res;
   bson_iter_t iter;
   bson_iter_t array_iter;
   double val;
   command = BCON_NEW ("distinct",
                       BCON_UTF8 (COLLECTION_NAME),
                       "key",
                       BCON_UTF8 ("x"),
                       "query",
                       "{",
                       "x",
                       "{",
                       "$gt",
                       BCON_DOUBLE (1.0),
                       "}",
                       "}");
   res = mongoc_database_command_simple (database, command, NULL, &reply, &error);
   if (!res) {
      fprintf (stderr, "Error with distinct: %s\n", error.message);
      goto cleanup;
   }
   /* Do something with reply (in this case iterate through the values) */
   if (!(bson_iter_init_find (&iter, &reply, "values") && BSON_ITER_HOLDS_ARRAY (&iter) &&
         bson_iter_recurse (&iter, &array_iter))) {
      fprintf (stderr, "Couldn't extract \"values\" field from response\n");
      goto cleanup;
   }
   while (bson_iter_next (&array_iter)) {
      if (BSON_ITER_HOLDS_DOUBLE (&array_iter)) {
         val = bson_iter_double (&array_iter);
         printf ("Next double: %f\n", val);
      }
   }
cleanup:
   /* cleanup */
   bson_destroy (command);
   bson_destroy (&reply);
   return res;
}

const char *const COLLECTION_NAME = "things";
/* Our map function just emits a single (key, 1) pair for each tag
   in the array: */
const char *const MAPPER = "function () {"
                           "this.tags.forEach(function(z) {"
                           "emit(z, 1);"
                           "});"
                           "}";
/* The reduce function sums over all of the emitted values for a
   given key: */
const char *const REDUCER = "function (key, values) {"
                            "var total = 0;"
                            "for (var i = 0; i < values.length; i++) {"
                            "total += values[i];"
                            "}"
                            "return total;"
                            "}";
/* Note We can't just return values.length as the reduce function
   might be called iteratively on the results of other reduce
   steps. */

bool
map_reduce_basic (mongoc_database_t *database)
{
   bson_t reply;
   bool res = false;
   bson_error_t error;
   mongoc_cursor_t *cursor = NULL;
   bool query_done = false;
   const char *out_collection_name = "outCollection";
   mongoc_collection_t *out_collection = NULL;
   /* Empty find query */
   bson_t find_query = BSON_INITIALIZER;
   /* Construct the mapReduce command */
   /* Other arguments can also be specified here, like "query" or
      "limit" and so on */
   bson_t *const command = BCON_NEW ("mapReduce",
                                     BCON_UTF8 (COLLECTION_NAME),
                                     "map",
                                     BCON_CODE (MAPPER),
                                     "reduce",
                                     BCON_CODE (REDUCER),
                                     "out",
                                     BCON_UTF8 (out_collection_name));
   res = mongoc_database_command_simple (database, command, NULL, &reply, &error);
   if (!res) {
      fprintf (stderr, "MapReduce failed: %s\n", error.message);
      goto cleanup;
   }
   /* Do something with the reply (it doesn't contain the mapReduce results) */
   print_res (&reply);
   /* Now we'll query outCollection to see what the results are */
   out_collection = mongoc_database_get_collection (database, out_collection_name);
   cursor = mongoc_collection_find_with_opts (out_collection, &find_query, NULL, NULL);
   query_done = true;
   /* Do something with the results */
   const bson_t *doc = NULL;
   while (mongoc_cursor_next (cursor, &doc)) {
      print_res (doc);
   }
   if (mongoc_cursor_error (cursor, &error)) {
      fprintf (stderr, "ERROR: %s\n", error.message);
      res = false;
      goto cleanup;
   }
cleanup:
   /* cleanup */
   if (query_done) {
      mongoc_cursor_destroy (cursor);
      mongoc_collection_destroy (out_collection);
   }
   bson_destroy (&reply);
   bson_destroy (command);
   return res;
}

bool
map_reduce_advanced (mongoc_database_t *database)
{
   bson_t *command;
   bson_error_t error;
   bool res = true;
   mongoc_cursor_t *cursor;
   mongoc_read_prefs_t *read_pref;
   const bson_t *doc;
   /* Construct the mapReduce command */
   /* Other arguments can also be specified here, like "query" or "limit"
      and so on */
   /* Read the results inline from a secondary replica */
   command = BCON_NEW ("mapReduce",
                       BCON_UTF8 (COLLECTION_NAME),
                       "map",
                       BCON_CODE (MAPPER),
                       "reduce",
                       BCON_CODE (REDUCER),
                       "out",
                       "{",
                       "inline",
                       "1",
                       "}");
   read_pref = mongoc_read_prefs_new (MONGOC_READ_SECONDARY);
   cursor = mongoc_database_command (database, MONGOC_QUERY_NONE, 0, 0, 0, command, NULL, read_pref);
   /* Do something with the results */
   while (mongoc_cursor_next (cursor, &doc)) {
      print_res (doc);
   }
   if (mongoc_cursor_error (cursor, &error)) {
      fprintf (stderr, "ERROR: %s\n", error.message);
      res = false;
   }
   mongoc_cursor_destroy (cursor);
   mongoc_read_prefs_destroy (read_pref);
   bson_destroy (command);
   return res;
}

/*
 * Copyright 2009-present MongoDB, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <mongoc/mongoc.h>
#include <stdio.h>
#include "constants.c"
#include "../doc-common-insert.c"
#include "distinct.c"
#include "map-reduce-basic.c"
#include "map-reduce-advanced.c"
int
main (int argc, char *argv[])
{
   mongoc_database_t *database = NULL;
   mongoc_client_t *client = NULL;
   mongoc_collection_t *collection = NULL;
   mongoc_uri_t *uri = NULL;
   bson_error_t error;
   char *host_and_port = NULL;
   int exit_code = EXIT_FAILURE;
   if (argc != 2) {
      fprintf (stderr, "usage: %s CONNECTION-STRING\n", argv[0]);
      fprintf (stderr, "the connection string can be of the following forms:\n");
      fprintf (stderr, "localhost\t\t\t\tlocal machine\n");
      fprintf (stderr, "localhost:27018\t\t\t\tlocal machine on port 27018\n");
      fprintf (stderr,
               "mongodb://user:pass@localhost:27017\t"
               "local machine on port 27017, and authenticate with username "
               "user and password pass\n");
      return exit_code;
   }
   mongoc_init ();
   if (strncmp (argv[1], "mongodb://", 10) == 0) {
      host_and_port = bson_strdup (argv[1]);
   } else {
      host_and_port = bson_strdup_printf ("mongodb://%s", argv[1]);
   }
   uri = mongoc_uri_new_with_error (host_and_port, &error);
   if (!uri) {
      fprintf (stderr,
               "failed to parse URI: %s\n"
               "error message:       %s\n",
               host_and_port,
               error.message);
      goto cleanup;
   }
   client = mongoc_client_new_from_uri (uri);
   if (!client) {
      goto cleanup;
   }
   mongoc_client_set_error_api (client, 2);
   database = mongoc_client_get_database (client, "test");
   collection = mongoc_database_get_collection (database, COLLECTION_NAME);
   printf ("Inserting data\n");
   if (!insert_data (collection)) {
      goto cleanup;
   }
   printf ("distinct\n");
   if (!distinct (database)) {
      goto cleanup;
   }
   printf ("map reduce\n");
   if (!map_reduce_basic (database)) {
      goto cleanup;
   }
   printf ("more complicated map reduce\n");
   if (!map_reduce_advanced (database)) {
      goto cleanup;
   }
   exit_code = EXIT_SUCCESS;
cleanup:
   if (collection) {
      mongoc_collection_destroy (collection);
   }
   if (database) {
      mongoc_database_destroy (database);
   }
   if (client) {
      mongoc_client_destroy (client);
   }
   if (uri) {
      mongoc_uri_destroy (uri);
   }
   if (host_and_port) {
      bson_free (host_and_port);
   }
   mongoc_cleanup ();
   return exit_code;
}