text: /*
   *
   * Copyright 2015, Google Inc.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer
   * in the documentation and/or other materials provided with the
   * distribution.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #include <string.h>
  
  #include <grpc/grpc.h>
  #include <grpc/support/alloc.h>
  
  #include "src/core/lib/client_config/resolver_registry.h"
  #include "src/core/lib/iomgr/resolve_address.h"
  #include "src/core/lib/iomgr/timer.h"
  #include "test/core/util/test_config.h"
  
  static void subchannel_factory_ref(grpc_subchannel_factory *scv) {}
  static void subchannel_factory_unref(grpc_exec_ctx *exec_ctx,
                                       grpc_subchannel_factory *scv) {}
  static grpc_subchannel *subchannel_factory_create_subchannel(
      grpc_exec_ctx *exec_ctx, grpc_subchannel_factory *factory,
      grpc_subchannel_args *args) {
    return NULL;
  }
  
  static const grpc_subchannel_factory_vtable sc_vtable = {
      subchannel_factory_ref, subchannel_factory_unref,
      subchannel_factory_create_subchannel};
  
  static grpc_subchannel_factory sc_factory = {&sc_vtable};
  
  static gpr_mu g_mu;
  static bool g_fail_resolution = true;
  
  static grpc_resolved_addresses *my_resolve_address(const char *name,
                                                     const char *addr) {
    gpr_mu_lock(&g_mu);
    GPR_ASSERT(0 == strcmp("test", name));
    if (g_fail_resolution) {
      g_fail_resolution = false;
      gpr_mu_unlock(&g_mu);
      return NULL;
    } else {
      gpr_mu_unlock(&g_mu);
      grpc_resolved_addresses *addrs = gpr_malloc(sizeof(*addrs));
      addrs->naddrs = 1;
      addrs->addrs = gpr_malloc(sizeof(*addrs->addrs));
      addrs->addrs[0].len = 123;
      return addrs;
    }
  }
  
  static grpc_resolver *create_resolver(const char *name) {
    grpc_resolver_factory *factory = grpc_resolver_factory_lookup("dns");
    grpc_uri *uri = grpc_uri_parse(name, 0);
    GPR_ASSERT(uri);
    grpc_resolver_args args;
    memset(&args, 0, sizeof(args));
    args.uri = uri;
    args.subchannel_factory = &sc_factory;
    grpc_resolver *resolver =
        grpc_resolver_factory_create_resolver(factory, &args);
    grpc_resolver_factory_unref(factory);
    grpc_uri_destroy(uri);
    return resolver;
  }
  
  static void on_done(grpc_exec_ctx *exec_ctx, void *ev, bool success) {
    gpr_event_set(ev, (void *)1);
  }
  
  // interleave waiting for an event with a timer check
  static bool wait_loop(int deadline_seconds, gpr_event *ev) {
    while (deadline_seconds) {
      gpr_log(GPR_DEBUG, "Test: waiting for %d more seconds", deadline_seconds);
      if (gpr_event_wait(ev, GRPC_TIMEOUT_SECONDS_TO_DEADLINE(1))) return true;
      deadline_seconds--;
  
      grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
      grpc_timer_check(&exec_ctx, gpr_now(GPR_CLOCK_MONOTONIC), NULL);
      grpc_exec_ctx_finish(&exec_ctx);
    }
    return false;
  }
  
  int main(int argc, char **argv) {
    grpc_test_init(argc, argv);
  
    grpc_init();
    gpr_mu_init(&g_mu);
    grpc_blocking_resolve_address = my_resolve_address;
  
    grpc_resolver *resolver = create_resolver("dns:test");
  
    grpc_client_config *config = (grpc_client_config *)1;
  
    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
    gpr_event ev1;
    gpr_event_init(&ev1);
    grpc_resolver_next(&exec_ctx, resolver, &config,
                       grpc_closure_create(on_done, &ev1));
    grpc_exec_ctx_flush(&exec_ctx);
    GPR_ASSERT(wait_loop(5, &ev1));
    GPR_ASSERT(config == NULL);
  
    gpr_event ev2;
    gpr_event_init(&ev2);
    grpc_resolver_next(&exec_ctx, resolver, &config,
                       grpc_closure_create(on_done, &ev2));
    grpc_exec_ctx_flush(&exec_ctx);
    GPR_ASSERT(wait_loop(30, &ev2));
    GPR_ASSERT(config != NULL);
  
    grpc_client_config_unref(&exec_ctx, config);
    GRPC_RESOLVER_UNREF(&exec_ctx, resolver, "test");
    grpc_exec_ctx_finish(&exec_ctx);
  
    grpc_shutdown();
    gpr_mu_destroy(&g_mu);
  }
  