add stub API for client bulk write

src/libmongoc/CMakeLists.txt

@@ -657,6 +657,7 @@ set (SOURCES ${SOURCES}
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-stream-tls-openssl-bio.c
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-openssl.c
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-ocsp-cache.c
+   ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-bulkwrite.c
 )
 
 set (HEADERS
@@ -665,6 +666,7 @@ set (HEADERS
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc.h
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-apm.h
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-bulk-operation.h
+   ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-bulkwrite.h
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-change-stream.h
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-client.h
    ${PROJECT_SOURCE_DIR}/src/mongoc/mongoc-client-pool.h
@@ -1216,6 +1218,7 @@ if (ENABLE_EXAMPLES AND ENABLE_SHARED)
    mongoc_add_example (mongoc-ping ${PROJECT_SOURCE_DIR}/examples/mongoc-ping.c)
    mongoc_add_example (mongoc-tail ${PROJECT_SOURCE_DIR}/examples/mongoc-tail.c)
    mongoc_add_example (example-collection-command ${PROJECT_SOURCE_DIR}/examples/example-collection-command.c)
+   mongoc_add_example (example-bulkwrite ${PROJECT_SOURCE_DIR}/examples/example-bulkwrite.c)
 
    # examples/aggregation/
    mongoc_add_example (aggregation1 ${PROJECT_SOURCE_DIR}/examples/aggregation/aggregation1.c)

src/libmongoc/examples/example-bulkwrite.c

@@ -0,0 +1,79 @@
+// example-bulkwrite shows use of `mongoc_client_bulkwrite`.
+
+#include <mongoc/mongoc.h>
+
+#define HANDLE_ERROR(...)            \
+   if (1) {                          \
+      fprintf (stderr, __VA_ARGS__); \
+      fprintf (stderr, "\n");        \
+      goto fail;                     \
+   } else                            \
+      (void) 0
+
+int
+main (int argc, char *argv[])
+{
+   bool ok = false;
+
+   mongoc_init ();
+
+   bson_error_t error;
+   mongoc_client_t *client = mongoc_client_new ("mongodb://localhost:27017");
+   mongoc_bulkwriteoptions_t *bwo = mongoc_bulkwriteoptions_new ();
+   mongoc_bulkwriteoptions_set_verboseresults (bwo, true);
+   mongoc_bulkwrite_t *bw = mongoc_client_bulkwrite_new (client, bwo);
+
+   // Insert a document to `db.coll1`
+   {
+      bson_t *doc = BCON_NEW ("foo", "1");
+      if (!mongoc_client_bulkwrite_append_insertone (bw, "db.coll1", -1, doc, NULL, &error)) {
+         HANDLE_ERROR ("error appending insert one: %s", error.message);
+      }
+      bson_destroy (doc);
+   }
+   // Insert a document to `db.coll2`
+   {
+      bson_t *doc = BCON_NEW ("foo", "2");
+      if (!mongoc_client_bulkwrite_append_insertone (bw, "db.coll2", -1, doc, NULL, &error)) {
+         HANDLE_ERROR ("error appending insert one: %s", error.message);
+      }
+      bson_destroy (doc);
+   }
+
+   mongoc_bulkwritereturn_t bwr = mongoc_bulkwrite_execute (bw);
+
+   printf ("insert count: %" PRId64 "\n", mongoc_bulkwriteresult_insertedcount (bwr.res));
+
+   // Print verbose results.
+   {
+      const bson_t *vr = mongoc_bulkwriteresult_verboseresults (bwr.res);
+      BSON_ASSERT (vr);
+      char *vr_str = bson_as_relaxed_extended_json (vr, NULL);
+      printf ("verbose results: %s\n", vr_str);
+      bson_free (vr_str);
+   }
+
+   // Print exception.
+   if (bwr.exc) {
+      const bson_t *error_doc;
+      mongoc_bulkwriteexception_error (bwr.exc, &error, &error_doc);
+      if (mongoc_error_has_label (error_doc, "RetryableWriteError")) {
+         printf ("error has label: RetryableWriteError\n");
+      }
+      printf ("error: %s\n", error.message);
+      char *error_doc_str = bson_as_relaxed_extended_json (error_doc, NULL);
+      printf ("exception: %s\n", error_doc_str);
+      bson_free (error_doc_str);
+   }
+
+   mongoc_bulkwriteresult_destroy (bwr.res);
+   mongoc_bulkwriteexception_destroy (bwr.exc);
+   mongoc_bulkwrite_destroy (bw);
+
+   ok = true;
+fail:
+   mongoc_client_destroy (client);
+   mongoc_bulkwriteoptions_destroy (bwo);
+   mongoc_cleanup ();
+   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
+}