s/NULL/nullptr

6 files changed, 114 insertions, 114 deletions

diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
index 76f08281f7..5f91fe05af 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -121,15 +121,15 @@ static void dns_ares_shutdown_locked(grpc_exec_ctx* exec_ctx,
   if (r->have_retry_timer) {
     grpc_timer_cancel(exec_ctx, &r->retry_timer);
   }
-  if (r->pending_request != NULL) {
+  if (r->pending_request != nullptr) {
     grpc_cancel_ares_request(exec_ctx, r->pending_request);
   }
-  if (r->next_completion != NULL) {
-    *r->target_result = NULL;
+  if (r->next_completion != nullptr) {
+    *r->target_result = nullptr;
     GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
@@ -155,7 +155,7 @@ static void dns_ares_on_retry_timer_locked(grpc_exec_ctx* exec_ctx, void* arg,
 }
 
 static bool value_in_json_array(grpc_json* array, const char* value) {
-  for (grpc_json* entry = array->child; entry != NULL; entry = entry->next) {
+  for (grpc_json* entry = array->child; entry != nullptr; entry = entry->next) {
     if (entry->type == GRPC_JSON_STRING && strcmp(entry->value, value) == 0) {
       return true;
     }
@@ -165,47 +165,47 @@ static bool value_in_json_array(grpc_json* array, const char* value) {
 
 static char* choose_service_config(char* service_config_choice_json) {
   grpc_json* choices_json = grpc_json_parse_string(service_config_choice_json);
-  if (choices_json == NULL || choices_json->type != GRPC_JSON_ARRAY) {
+  if (choices_json == nullptr || choices_json->type != GRPC_JSON_ARRAY) {
     gpr_log(GPR_ERROR, "cannot parse service config JSON string");
-    return NULL;
+    return nullptr;
   }
-  char* service_config = NULL;
-  for (grpc_json* choice = choices_json->child; choice != NULL;
+  char* service_config = nullptr;
+  for (grpc_json* choice = choices_json->child; choice != nullptr;
        choice = choice->next) {
     if (choice->type != GRPC_JSON_OBJECT) {
       gpr_log(GPR_ERROR, "cannot parse service config JSON string");
       break;
     }
-    grpc_json* service_config_json = NULL;
-    for (grpc_json* field = choice->child; field != NULL; field = field->next) {
+    grpc_json* service_config_json = nullptr;
+    for (grpc_json* field = choice->child; field != nullptr; field = field->next) {
       // Check client language, if specified.
       if (strcmp(field->key, "clientLanguage") == 0) {
         if (field->type != GRPC_JSON_ARRAY ||
             !value_in_json_array(field, "c++")) {
-          service_config_json = NULL;
+          service_config_json = nullptr;
           break;
         }
       }
       // Check client hostname, if specified.
       if (strcmp(field->key, "clientHostname") == 0) {
         char* hostname = grpc_gethostname();
-        if (hostname == NULL || field->type != GRPC_JSON_ARRAY ||
+        if (hostname == nullptr || field->type != GRPC_JSON_ARRAY ||
             !value_in_json_array(field, hostname)) {
-          service_config_json = NULL;
+          service_config_json = nullptr;
           break;
         }
       }
       // Check percentage, if specified.
       if (strcmp(field->key, "percentage") == 0) {
         if (field->type != GRPC_JSON_NUMBER) {
-          service_config_json = NULL;
+          service_config_json = nullptr;
           break;
         }
         int random_pct = rand() % 100;
         int percentage;
         if (sscanf(field->value, "%d", &percentage) != 1 ||
             random_pct > percentage || percentage == 0) {
-          service_config_json = NULL;
+          service_config_json = nullptr;
           break;
         }
       }
@@ -216,7 +216,7 @@ static char* choose_service_config(char* service_config_choice_json) {
         }
       }
     }
-    if (service_config_json != NULL) {
+    if (service_config_json != nullptr) {
       service_config = grpc_json_dump_to_string(service_config_json, 0);
       break;
     }
@@ -228,33 +228,33 @@ static char* choose_service_config(char* service_config_choice_json) {
 static void dns_ares_on_resolved_locked(grpc_exec_ctx* exec_ctx, void* arg,
                                         grpc_error* error) {
   ares_dns_resolver* r = (ares_dns_resolver*)arg;
-  grpc_channel_args* result = NULL;
+  grpc_channel_args* result = nullptr;
   GPR_ASSERT(r->resolving);
   r->resolving = false;
-  r->pending_request = NULL;
-  if (r->lb_addresses != NULL) {
+  r->pending_request = nullptr;
+  if (r->lb_addresses != nullptr) {
     static const char* args_to_remove[2];
     size_t num_args_to_remove = 0;
     grpc_arg new_args[3];
     size_t num_args_to_add = 0;
     new_args[num_args_to_add++] =
         grpc_lb_addresses_create_channel_arg(r->lb_addresses);
-    grpc_service_config* service_config = NULL;
-    char* service_config_string = NULL;
-    if (r->service_config_json != NULL) {
+    grpc_service_config* service_config = nullptr;
+    char* service_config_string = nullptr;
+    if (r->service_config_json != nullptr) {
       service_config_string = choose_service_config(r->service_config_json);
       gpr_free(r->service_config_json);
-      if (service_config_string != NULL) {
+      if (service_config_string != nullptr) {
         gpr_log(GPR_INFO, "selected service config choice: %s",
                 service_config_string);
         args_to_remove[num_args_to_remove++] = GRPC_ARG_SERVICE_CONFIG;
         new_args[num_args_to_add++] = grpc_channel_arg_string_create(
             (char*)GRPC_ARG_SERVICE_CONFIG, service_config_string);
         service_config = grpc_service_config_create(service_config_string);
-        if (service_config != NULL) {
+        if (service_config != nullptr) {
           const char* lb_policy_name =
               grpc_service_config_get_lb_policy_name(service_config);
-          if (lb_policy_name != NULL) {
+          if (lb_policy_name != nullptr) {
             args_to_remove[num_args_to_remove++] = GRPC_ARG_LB_POLICY_NAME;
             new_args[num_args_to_add++] = grpc_channel_arg_string_create(
                 (char*)GRPC_ARG_LB_POLICY_NAME, (char*)lb_policy_name);
@@ -265,7 +265,7 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx* exec_ctx, void* arg,
     result = grpc_channel_args_copy_and_add_and_remove(
         r->channel_args, args_to_remove, num_args_to_remove, new_args,
         num_args_to_add);
-    if (service_config != NULL) grpc_service_config_destroy(service_config);
+    if (service_config != nullptr) grpc_service_config_destroy(service_config);
     gpr_free(service_config_string);
     grpc_lb_addresses_destroy(exec_ctx, r->lb_addresses);
   } else {
@@ -287,7 +287,7 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx* exec_ctx, void* arg,
     grpc_timer_init(exec_ctx, &r->retry_timer, next_try,
                     &r->dns_ares_on_retry_timer_locked);
   }
-  if (r->resolved_result != NULL) {
+  if (r->resolved_result != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   r->resolved_result = result;
@@ -318,25 +318,25 @@ static void dns_ares_start_resolving_locked(grpc_exec_ctx* exec_ctx,
   GRPC_RESOLVER_REF(&r->base, "dns-resolving");
   GPR_ASSERT(!r->resolving);
   r->resolving = true;
-  r->lb_addresses = NULL;
-  r->service_config_json = NULL;
+  r->lb_addresses = nullptr;
+  r->service_config_json = nullptr;
   r->pending_request = grpc_dns_lookup_ares(
       exec_ctx, r->dns_server, r->name_to_resolve, r->default_port,
       r->interested_parties, &r->dns_ares_on_resolved_locked, &r->lb_addresses,
       true /* check_grpclb */,
-      r->request_service_config ? &r->service_config_json : NULL);
+      r->request_service_config ? &r->service_config_json : nullptr);
 }
 
 static void dns_ares_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
                                               ares_dns_resolver* r) {
-  if (r->next_completion != NULL &&
+  if (r->next_completion != nullptr &&
       r->resolved_version != r->published_version) {
-    *r->target_result = r->resolved_result == NULL
-                            ? NULL
+    *r->target_result = r->resolved_result == nullptr
+                            ? nullptr
                             : grpc_channel_args_copy(r->resolved_result);
     gpr_log(GPR_DEBUG, "dns_ares_maybe_finish_next_locked");
     GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
     r->published_version = r->resolved_version;
   }
 }
@@ -344,7 +344,7 @@ static void dns_ares_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
 static void dns_ares_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
   gpr_log(GPR_DEBUG, "dns_ares_destroy");
   ares_dns_resolver* r = (ares_dns_resolver*)gr;
-  if (r->resolved_result != NULL) {
+  if (r->resolved_result != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   grpc_pollset_set_destroy(exec_ctx, r->interested_parties);
@@ -376,7 +376,7 @@ static grpc_resolver* dns_ares_create(grpc_exec_ctx* exec_ctx,
   r->request_service_config = !grpc_channel_arg_get_integer(
       arg, (grpc_integer_options){false, false, true});
   r->interested_parties = grpc_pollset_set_create();
-  if (args->pollset_set != NULL) {
+  if (args->pollset_set != nullptr) {
     grpc_pollset_set_add_pollset_set(exec_ctx, r->interested_parties,
                                      args->pollset_set);
   }
@@ -428,7 +428,7 @@ extern "C" void grpc_resolver_dns_ares_init(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
   /* TODO(zyc): Turn on c-ares based resolver by default after the address
      sorter and the CNAME support are added. */
-  if (resolver != NULL && gpr_stricmp(resolver, "ares") == 0) {
+  if (resolver != nullptr && gpr_stricmp(resolver, "ares") == 0) {
     grpc_error* error = grpc_ares_init();
     if (error != GRPC_ERROR_NONE) {
       GRPC_LOG_IF_ERROR("ares_library_init() failed", error);
@@ -442,7 +442,7 @@ extern "C" void grpc_resolver_dns_ares_init(void) {
 
 extern "C" void grpc_resolver_dns_ares_shutdown(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
-  if (resolver != NULL && gpr_stricmp(resolver, "ares") == 0) {
+  if (resolver != nullptr && gpr_stricmp(resolver, "ares") == 0) {
     grpc_ares_cleanup();
   }
   gpr_free(resolver);
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
index 2bb98c1a3f..92c72c1bcb 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
@@ -91,7 +91,7 @@ static void grpc_ares_ev_driver_unref(grpc_ares_ev_driver* ev_driver) {
   gpr_log(GPR_DEBUG, "Unref ev_driver %" PRIuPTR, (uintptr_t)ev_driver);
   if (gpr_unref(&ev_driver->refs)) {
     gpr_log(GPR_DEBUG, "destroy ev_driver %" PRIuPTR, (uintptr_t)ev_driver);
-    GPR_ASSERT(ev_driver->fds == NULL);
+    GPR_ASSERT(ev_driver->fds == nullptr);
     gpr_mu_destroy(&ev_driver->mu);
     ares_destroy(ev_driver->channel);
     gpr_free(ev_driver);
@@ -106,7 +106,7 @@ static void fd_node_destroy(grpc_exec_ctx* exec_ctx, fd_node* fdn) {
   /* c-ares library has closed the fd inside grpc_fd. This fd may be picked up
      immediately by another thread, and should not be closed by the following
      grpc_fd_orphan. */
-  grpc_fd_orphan(exec_ctx, fdn->fd, NULL, NULL, true /* already_closed */,
+  grpc_fd_orphan(exec_ctx, fdn->fd, nullptr, nullptr, true /* already_closed */,
                  "c-ares query finished");
   gpr_free(fdn);
 }
@@ -142,7 +142,7 @@ grpc_error* grpc_ares_ev_driver_create(grpc_ares_ev_driver** ev_driver,
   gpr_mu_init(&(*ev_driver)->mu);
   gpr_ref_init(&(*ev_driver)->refs, 1);
   (*ev_driver)->pollset_set = pollset_set;
-  (*ev_driver)->fds = NULL;
+  (*ev_driver)->fds = nullptr;
   (*ev_driver)->working = false;
   (*ev_driver)->shutting_down = false;
   return GRPC_ERROR_NONE;
@@ -165,7 +165,7 @@ void grpc_ares_ev_driver_shutdown(grpc_exec_ctx* exec_ctx,
   gpr_mu_lock(&ev_driver->mu);
   ev_driver->shutting_down = true;
   fd_node* fn = ev_driver->fds;
-  while (fn != NULL) {
+  while (fn != nullptr) {
     grpc_fd_shutdown(
         exec_ctx, fn->fd,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("grpc_ares_ev_driver_shutdown"));
@@ -180,7 +180,7 @@ static fd_node* pop_fd_node(fd_node** head, int fd) {
   fd_node dummy_head;
   dummy_head.next = *head;
   fd_node* node = &dummy_head;
-  while (node->next != NULL) {
+  while (node->next != nullptr) {
     if (grpc_fd_wrapped_fd(node->next->fd) == fd) {
       fd_node* ret = node->next;
       node->next = node->next->next;
@@ -189,7 +189,7 @@ static fd_node* pop_fd_node(fd_node** head, int fd) {
     }
     node = node->next;
   }
-  return NULL;
+  return nullptr;
 }
 
 /* Check if \a fd is still readable */
@@ -275,7 +275,7 @@ ares_channel* grpc_ares_ev_driver_get_channel(grpc_ares_ev_driver* ev_driver) {
 // driver_closure with these filedescriptors.
 static void grpc_ares_notify_on_event_locked(grpc_exec_ctx* exec_ctx,
                                              grpc_ares_ev_driver* ev_driver) {
-  fd_node* new_list = NULL;
+  fd_node* new_list = nullptr;
   if (!ev_driver->shutting_down) {
     ares_socket_t socks[ARES_GETSOCK_MAXNUM];
     int socks_bitmask =
@@ -332,14 +332,14 @@ static void grpc_ares_notify_on_event_locked(grpc_exec_ctx* exec_ctx,
   // Any remaining fds in ev_driver->fds were not returned by ares_getsock() and
   // are therefore no longer in use, so they can be shut down and removed from
   // the list.
-  while (ev_driver->fds != NULL) {
+  while (ev_driver->fds != nullptr) {
     fd_node* cur = ev_driver->fds;
     ev_driver->fds = ev_driver->fds->next;
     fd_node_shutdown(exec_ctx, cur);
   }
   ev_driver->fds = new_list;
   // If the ev driver has no working fd, all the tasks are done.
-  if (new_list == NULL) {
+  if (new_list == nullptr) {
     ev_driver->working = false;
     gpr_log(GPR_DEBUG, "ev driver stop working");
   }
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
index 9408b9d81d..af4493389d 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
@@ -102,7 +102,7 @@ static void grpc_ares_request_unref(grpc_exec_ctx* exec_ctx,
      request */
   if (gpr_unref(&r->pending_queries)) {
     /* TODO(zyc): Sort results with RFC6724 before invoking on_done. */
-    if (exec_ctx == NULL) {
+    if (exec_ctx == nullptr) {
       /* A new exec_ctx is created here, as the c-ares interface does not
          provide one in ares_host_callback. It's safe to schedule on_done with
          the newly created exec_ctx, since the caller has been warned not to
@@ -150,12 +150,12 @@ static void on_hostbyname_done_cb(void* arg, int status, int timeouts,
     r->error = GRPC_ERROR_NONE;
     r->success = true;
     grpc_lb_addresses** lb_addresses = r->lb_addrs_out;
-    if (*lb_addresses == NULL) {
-      *lb_addresses = grpc_lb_addresses_create(0, NULL);
+    if (*lb_addresses == nullptr) {
+      *lb_addresses = grpc_lb_addresses_create(0, nullptr);
     }
     size_t prev_naddr = (*lb_addresses)->num_addresses;
     size_t i;
-    for (i = 0; hostent->h_addr_list[i] != NULL; i++) {
+    for (i = 0; hostent->h_addr_list[i] != nullptr; i++) {
     }
     (*lb_addresses)->num_addresses += i;
     (*lb_addresses)->addresses = (grpc_lb_address*)gpr_realloc(
@@ -174,8 +174,8 @@ static void on_hostbyname_done_cb(void* arg, int status, int timeouts,
           grpc_lb_addresses_set_address(
               *lb_addresses, i, &addr, addr_len,
               hr->is_balancer /* is_balancer */,
-              hr->is_balancer ? hr->host : NULL /* balancer_name */,
-              NULL /* user_data */);
+              hr->is_balancer ? hr->host : nullptr /* balancer_name */,
+              nullptr /* user_data */);
           char output[INET6_ADDRSTRLEN];
           ares_inet_ntop(AF_INET6, &addr.sin6_addr, output, INET6_ADDRSTRLEN);
           gpr_log(GPR_DEBUG,
@@ -195,8 +195,8 @@ static void on_hostbyname_done_cb(void* arg, int status, int timeouts,
           grpc_lb_addresses_set_address(
               *lb_addresses, i, &addr, addr_len,
               hr->is_balancer /* is_balancer */,
-              hr->is_balancer ? hr->host : NULL /* balancer_name */,
-              NULL /* user_data */);
+              hr->is_balancer ? hr->host : nullptr /* balancer_name */,
+              nullptr /* user_data */);
           char output[INET_ADDRSTRLEN];
           ares_inet_ntop(AF_INET, &addr.sin_addr, output, INET_ADDRSTRLEN);
           gpr_log(GPR_DEBUG,
@@ -220,7 +220,7 @@ static void on_hostbyname_done_cb(void* arg, int status, int timeouts,
     }
   }
   gpr_mu_unlock(&r->mu);
-  destroy_hostbyname_request(NULL, hr);
+  destroy_hostbyname_request(nullptr, hr);
 }
 
 static void on_srv_query_done_cb(void* arg, int status, int timeouts,
@@ -234,7 +234,7 @@ static void on_srv_query_done_cb(void* arg, int status, int timeouts,
     const int parse_status = ares_parse_srv_reply(abuf, alen, &reply);
     if (parse_status == ARES_SUCCESS) {
       ares_channel* channel = grpc_ares_ev_driver_get_channel(r->ev_driver);
-      for (struct ares_srv_reply* srv_it = reply; srv_it != NULL;
+      for (struct ares_srv_reply* srv_it = reply; srv_it != nullptr;
            srv_it = srv_it->next) {
         if (grpc_ipv6_loopback_available()) {
           grpc_ares_hostbyname_request* hr = create_hostbyname_request(
@@ -249,7 +249,7 @@ static void on_srv_query_done_cb(void* arg, int status, int timeouts,
         grpc_ares_ev_driver_start(&exec_ctx, r->ev_driver);
       }
     }
-    if (reply != NULL) {
+    if (reply != nullptr) {
       ares_free_data(reply);
     }
   } else if (!r->success) {
@@ -276,15 +276,15 @@ static void on_txt_done_cb(void* arg, int status, int timeouts,
   char* error_msg;
   grpc_ares_request* r = (grpc_ares_request*)arg;
   const size_t prefix_len = sizeof(g_service_config_attribute_prefix) - 1;
-  struct ares_txt_ext* result = NULL;
-  struct ares_txt_ext* reply = NULL;
+  struct ares_txt_ext* result = nullptr;
+  struct ares_txt_ext* reply = nullptr;
   grpc_error* error = GRPC_ERROR_NONE;
   gpr_mu_lock(&r->mu);
   if (status != ARES_SUCCESS) goto fail;
   status = ares_parse_txt_reply_ext(buf, len, &reply);
   if (status != ARES_SUCCESS) goto fail;
   // Find service config in TXT record.
-  for (result = reply; result != NULL; result = result->next) {
+  for (result = reply; result != nullptr; result = result->next) {
     if (result->record_start &&
         memcmp(result->txt, g_service_config_attribute_prefix, prefix_len) ==
             0) {
@@ -292,7 +292,7 @@ static void on_txt_done_cb(void* arg, int status, int timeouts,
     }
   }
   // Found a service config record.
-  if (result != NULL) {
+  if (result != nullptr) {
     size_t service_config_len = result->length - prefix_len;
     *r->service_config_json_out = (char*)gpr_malloc(service_config_len + 1);
     memcpy(*r->service_config_json_out, result->txt + prefix_len,
@@ -323,7 +323,7 @@ fail:
   }
 done:
   gpr_mu_unlock(&r->mu);
-  grpc_ares_request_unref(NULL, r);
+  grpc_ares_request_unref(nullptr, r);
 }
 
 static grpc_ares_request* grpc_dns_lookup_ares_impl(
@@ -332,8 +332,8 @@ static grpc_ares_request* grpc_dns_lookup_ares_impl(
     grpc_closure* on_done, grpc_lb_addresses** addrs, bool check_grpclb,
     char** service_config_json) {
   grpc_error* error = GRPC_ERROR_NONE;
-  grpc_ares_hostbyname_request* hr = NULL;
-  grpc_ares_request* r = NULL;
+  grpc_ares_hostbyname_request* hr = nullptr;
+  grpc_ares_request* r = nullptr;
   ares_channel* channel = NULL;
   /* TODO(zyc): Enable tracing after #9603 is checked in */
   /* if (grpc_dns_trace) {
@@ -345,13 +345,13 @@ static grpc_ares_request* grpc_dns_lookup_ares_impl(
   char* host;
   char* port;
   gpr_split_host_port(name, &host, &port);
-  if (host == NULL) {
+  if (host == nullptr) {
     error = grpc_error_set_str(
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("unparseable host:port"),
         GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
     goto error_cleanup;
-  } else if (port == NULL) {
-    if (default_port == NULL) {
+  } else if (port == nullptr) {
+    if (default_port == nullptr) {
       error = grpc_error_set_str(
           GRPC_ERROR_CREATE_FROM_STATIC_STRING("no port in name"),
           GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
@@ -375,7 +375,7 @@ static grpc_ares_request* grpc_dns_lookup_ares_impl(
   channel = grpc_ares_ev_driver_get_channel(r->ev_driver);
 
   // If dns_server is specified, use it.
-  if (dns_server != NULL) {
+  if (dns_server != nullptr) {
     gpr_log(GPR_INFO, "Using DNS server %s", dns_server);
     grpc_resolved_address addr;
     if (grpc_parse_ipv4_hostport(dns_server, &addr, false /* log_errors */)) {
@@ -429,7 +429,7 @@ static grpc_ares_request* grpc_dns_lookup_ares_impl(
                r);
     gpr_free(service_name);
   }
-  if (service_config_json != NULL) {
+  if (service_config_json != nullptr) {
     grpc_ares_request_ref(r);
     ares_search(*channel, hr->host, ns_c_in, ns_t_txt, on_txt_done_cb, r);
   }
@@ -444,7 +444,7 @@ error_cleanup:
   GRPC_CLOSURE_SCHED(exec_ctx, on_done, error);
   gpr_free(host);
   gpr_free(port);
-  return NULL;
+  return nullptr;
 }
 
 grpc_ares_request* (*grpc_dns_lookup_ares)(
@@ -503,8 +503,8 @@ static void on_dns_lookup_done_cb(grpc_exec_ctx* exec_ctx, void* arg,
   grpc_resolve_address_ares_request* r =
       (grpc_resolve_address_ares_request*)arg;
   grpc_resolved_addresses** resolved_addresses = r->addrs_out;
-  if (r->lb_addrs == NULL || r->lb_addrs->num_addresses == 0) {
-    *resolved_addresses = NULL;
+  if (r->lb_addrs == nullptr || r->lb_addrs->num_addresses == 0) {
+    *resolved_addresses = nullptr;
   } else {
     *resolved_addresses =
         (grpc_resolved_addresses*)gpr_zalloc(sizeof(grpc_resolved_addresses));
@@ -536,10 +536,10 @@ static void grpc_resolve_address_ares_impl(grpc_exec_ctx* exec_ctx,
   r->on_resolve_address_done = on_done;
   GRPC_CLOSURE_INIT(&r->on_dns_lookup_done, on_dns_lookup_done_cb, r,
                     grpc_schedule_on_exec_ctx);
-  grpc_dns_lookup_ares(exec_ctx, NULL /* dns_server */, name, default_port,
+  grpc_dns_lookup_ares(exec_ctx, nullptr /* dns_server */, name, default_port,
                        interested_parties, &r->on_dns_lookup_done, &r->lb_addrs,
                        false /* check_grpclb */,
-                       NULL /* service_config_json */);
+                       nullptr /* service_config_json */);
 }
 
 void (*grpc_resolve_address_ares)(
diff --git a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
index a57ab66118..589c74807f 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
@@ -100,12 +100,12 @@ static void dns_shutdown_locked(grpc_exec_ctx* exec_ctx,
   if (r->have_retry_timer) {
     grpc_timer_cancel(exec_ctx, &r->retry_timer);
   }
-  if (r->next_completion != NULL) {
-    *r->target_result = NULL;
+  if (r->next_completion != nullptr) {
+    *r->target_result = nullptr;
     GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
@@ -150,20 +150,20 @@ static void dns_on_retry_timer_locked(grpc_exec_ctx* exec_ctx, void* arg,
 static void dns_on_resolved_locked(grpc_exec_ctx* exec_ctx, void* arg,
                                    grpc_error* error) {
   dns_resolver* r = (dns_resolver*)arg;
-  grpc_channel_args* result = NULL;
+  grpc_channel_args* result = nullptr;
   GPR_ASSERT(r->resolving);
   r->resolving = false;
   GRPC_ERROR_REF(error);
   error = grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
                              grpc_slice_from_copied_string(r->name_to_resolve));
-  if (r->addresses != NULL) {
+  if (r->addresses != nullptr) {
     grpc_lb_addresses* addresses = grpc_lb_addresses_create(
-        r->addresses->naddrs, NULL /* user_data_vtable */);
+        r->addresses->naddrs, nullptr /* user_data_vtable */);
     for (size_t i = 0; i < r->addresses->naddrs; ++i) {
       grpc_lb_addresses_set_address(
           addresses, i, &r->addresses->addrs[i].addr,
           r->addresses->addrs[i].len, false /* is_balancer */,
-          NULL /* balancer_name */, NULL /* user_data */);
+          nullptr /* balancer_name */, nullptr /* user_data */);
     }
     grpc_arg new_arg = grpc_lb_addresses_create_channel_arg(addresses);
     result = grpc_channel_args_copy_and_add(r->channel_args, &new_arg, 1);
@@ -187,7 +187,7 @@ static void dns_on_resolved_locked(grpc_exec_ctx* exec_ctx, void* arg,
                       grpc_combiner_scheduler(r->base.combiner));
     grpc_timer_init(exec_ctx, &r->retry_timer, next_try, &r->on_retry);
   }
-  if (r->resolved_result != NULL) {
+  if (r->resolved_result != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   r->resolved_result = result;
@@ -203,7 +203,7 @@ static void dns_start_resolving_locked(grpc_exec_ctx* exec_ctx,
   GRPC_RESOLVER_REF(&r->base, "dns-resolving");
   GPR_ASSERT(!r->resolving);
   r->resolving = true;
-  r->addresses = NULL;
+  r->addresses = nullptr;
   grpc_resolve_address(
       exec_ctx, r->name_to_resolve, r->default_port, r->interested_parties,
       GRPC_CLOSURE_CREATE(dns_on_resolved_locked, r,
@@ -213,20 +213,20 @@ static void dns_start_resolving_locked(grpc_exec_ctx* exec_ctx,
 
 static void dns_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
                                          dns_resolver* r) {
-  if (r->next_completion != NULL &&
+  if (r->next_completion != nullptr &&
       r->resolved_version != r->published_version) {
-    *r->target_result = r->resolved_result == NULL
-                            ? NULL
+    *r->target_result = r->resolved_result == nullptr
+                            ? nullptr
                             : grpc_channel_args_copy(r->resolved_result);
     GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
     r->published_version = r->resolved_version;
   }
 }
 
 static void dns_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
   dns_resolver* r = (dns_resolver*)gr;
-  if (r->resolved_result != NULL) {
+  if (r->resolved_result != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   grpc_pollset_set_destroy(exec_ctx, r->interested_parties);
@@ -241,7 +241,7 @@ static grpc_resolver* dns_create(grpc_exec_ctx* exec_ctx,
                                  const char* default_port) {
   if (0 != strcmp(args->uri->authority, "")) {
     gpr_log(GPR_ERROR, "authority based dns uri's not supported");
-    return NULL;
+    return nullptr;
   }
   // Get name from args.
   char* path = args->uri->path;
@@ -253,7 +253,7 @@ static grpc_resolver* dns_create(grpc_exec_ctx* exec_ctx,
   r->default_port = gpr_strdup(default_port);
   r->channel_args = grpc_channel_args_copy(args->args);
   r->interested_parties = grpc_pollset_set_create();
-  if (args->pollset_set != NULL) {
+  if (args->pollset_set != nullptr) {
     grpc_pollset_set_add_pollset_set(exec_ctx, r->interested_parties,
                                      args->pollset_set);
   }
@@ -297,13 +297,13 @@ static grpc_resolver_factory* dns_resolver_factory_create() {
 
 extern "C" void grpc_resolver_dns_native_init(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
-  if (resolver != NULL && gpr_stricmp(resolver, "native") == 0) {
+  if (resolver != nullptr && gpr_stricmp(resolver, "native") == 0) {
     gpr_log(GPR_DEBUG, "Using native dns resolver");
     grpc_register_resolver_type(dns_resolver_factory_create());
   } else {
     grpc_resolver_factory* existing_factory =
         grpc_resolver_factory_lookup("dns");
-    if (existing_factory == NULL) {
+    if (existing_factory == nullptr) {
       gpr_log(GPR_DEBUG, "Using native dns resolver");
       grpc_register_resolver_type(dns_resolver_factory_create());
     } else {
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
index ed5b1011fb..85d7090144 100644
--- a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
@@ -78,31 +78,31 @@ static void fake_resolver_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
 static void fake_resolver_shutdown_locked(grpc_exec_ctx* exec_ctx,
                                           grpc_resolver* resolver) {
   fake_resolver* r = (fake_resolver*)resolver;
-  if (r->next_completion != NULL) {
-    *r->target_result = NULL;
+  if (r->next_completion != nullptr) {
+    *r->target_result = nullptr;
     GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
 static void fake_resolver_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
                                                    fake_resolver* r) {
-  if (r->next_completion != NULL && r->next_results != NULL) {
+  if (r->next_completion != nullptr && r->next_results != nullptr) {
     *r->target_result =
         grpc_channel_args_union(r->next_results, r->channel_args);
     grpc_channel_args_destroy(exec_ctx, r->next_results);
-    r->next_results = NULL;
+    r->next_results = nullptr;
     GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
 static void fake_resolver_channel_saw_error_locked(grpc_exec_ctx* exec_ctx,
                                                    grpc_resolver* resolver) {
   fake_resolver* r = (fake_resolver*)resolver;
-  if (r->next_results == NULL && r->results_upon_error != NULL) {
+  if (r->next_results == nullptr && r->results_upon_error != nullptr) {
     // Pretend we re-resolved.
     r->next_results = grpc_channel_args_copy(r->results_upon_error);
   }
@@ -162,11 +162,11 @@ static void set_response_closure_fn(grpc_exec_ctx* exec_ctx, void* arg,
   set_response_closure_arg* closure_arg = (set_response_closure_arg*)arg;
   grpc_fake_resolver_response_generator* generator = closure_arg->generator;
   fake_resolver* r = generator->resolver;
-  if (r->next_results != NULL) {
+  if (r->next_results != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->next_results);
   }
   r->next_results = closure_arg->next_response;
-  if (r->results_upon_error != NULL) {
+  if (r->results_upon_error != nullptr) {
     grpc_channel_args_destroy(exec_ctx, r->results_upon_error);
   }
   r->results_upon_error = grpc_channel_args_copy(closure_arg->next_response);
@@ -177,7 +177,7 @@ static void set_response_closure_fn(grpc_exec_ctx* exec_ctx, void* arg,
 void grpc_fake_resolver_response_generator_set_response(
     grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
     grpc_channel_args* next_response) {
-  GPR_ASSERT(generator->resolver != NULL);
+  GPR_ASSERT(generator->resolver != nullptr);
   set_response_closure_arg* closure_arg =
       (set_response_closure_arg*)gpr_zalloc(sizeof(*closure_arg));
   closure_arg->generator = generator;
@@ -220,7 +220,7 @@ grpc_fake_resolver_response_generator*
 grpc_fake_resolver_get_response_generator(const grpc_channel_args* args) {
   const grpc_arg* arg =
       grpc_channel_args_find(args, GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR);
-  if (arg == NULL || arg->type != GRPC_ARG_POINTER) return NULL;
+  if (arg == nullptr || arg->type != GRPC_ARG_POINTER) return nullptr;
   return (grpc_fake_resolver_response_generator*)arg->value.pointer.p;
 }
 
@@ -240,7 +240,7 @@ static grpc_resolver* fake_resolver_create(grpc_exec_ctx* exec_ctx,
   grpc_resolver_init(&r->base, &fake_resolver_vtable, args->combiner);
   grpc_fake_resolver_response_generator* response_generator =
       grpc_fake_resolver_get_response_generator(args->args);
-  if (response_generator != NULL) response_generator->resolver = r;
+  if (response_generator != nullptr) response_generator->resolver = r;
   return &r->base;
 }
 
diff --git a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
index 9fc8dffea3..82afd1d8b7 100644
--- a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
@@ -71,12 +71,12 @@ static const grpc_resolver_vtable sockaddr_resolver_vtable = {
 static void sockaddr_shutdown_locked(grpc_exec_ctx* exec_ctx,
                                      grpc_resolver* resolver) {
   sockaddr_resolver* r = (sockaddr_resolver*)resolver;
-  if (r->next_completion != NULL) {
-    *r->target_result = NULL;
+  if (r->next_completion != nullptr) {
+    *r->target_result = nullptr;
     GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
@@ -100,13 +100,13 @@ static void sockaddr_next_locked(grpc_exec_ctx* exec_ctx,
 
 static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
                                               sockaddr_resolver* r) {
-  if (r->next_completion != NULL && !r->published) {
+  if (r->next_completion != nullptr && !r->published) {
     r->published = true;
     grpc_arg arg = grpc_lb_addresses_create_channel_arg(r->addresses);
     *r->target_result =
         grpc_channel_args_copy_and_add(r->channel_args, &arg, 1);
     GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
+    r->next_completion = nullptr;
   }
 }
 
@@ -149,7 +149,7 @@ static grpc_resolver* sockaddr_create(grpc_exec_ctx* exec_ctx,
   if (0 != strcmp(args->uri->authority, "")) {
     gpr_log(GPR_ERROR, "authority based uri's not supported by the %s scheme",
             args->uri->scheme);
-    return NULL;
+    return nullptr;
   }
   /* Construct addresses. */
   grpc_slice path_slice =
@@ -158,7 +158,7 @@ static grpc_resolver* sockaddr_create(grpc_exec_ctx* exec_ctx,
   grpc_slice_buffer_init(&path_parts);
   grpc_slice_split(path_slice, ",", &path_parts);
   grpc_lb_addresses* addresses =
-      grpc_lb_addresses_create(path_parts.count, NULL /* user_data_vtable */);
+      grpc_lb_addresses_create(path_parts.count, nullptr /* user_data_vtable */);
   bool errors_found = false;
   for (size_t i = 0; i < addresses->num_addresses; i++) {
     grpc_uri ith_uri = *args->uri;
@@ -174,7 +174,7 @@ static grpc_resolver* sockaddr_create(grpc_exec_ctx* exec_ctx,
   grpc_slice_unref_internal(exec_ctx, path_slice);
   if (errors_found) {
     grpc_lb_addresses_destroy(exec_ctx, addresses);
-    return NULL;
+    return nullptr;
   }
   /* Instantiate resolver. */
   sockaddr_resolver* r =