// Starts the deadline timer.
static void start_timer_if_needed(grpc_exec_ctx* exec_ctx,
grpc_call_element* elem,
gpr_timespec deadline) {
grpc_deadline_state* deadline_state = elem->call_data;
deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
if (gpr_time_cmp(deadline, gpr_inf_future(GPR_CLOCK_MONOTONIC)) != 0) {
// Take a reference to the call stack, to be owned by the timer.
GRPC_CALL_STACK_REF(deadline_state->call_stack, "deadline_timer");
gpr_mu_lock(&deadline_state->timer_mu);
deadline_state->timer_pending = true;
grpc_timer_init(exec_ctx, &deadline_state->timer, deadline, timer_callback,
elem, gpr_now(GPR_CLOCK_MONOTONIC));
gpr_mu_unlock(&deadline_state->timer_mu);
}
}
/* Constructor for call_data */
static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
grpc_call_element *elem,
grpc_call_element_args *args) {
channel_data *chand = elem->channel_data;
call_data *calld = elem->call_data;
// Initialize data members.
grpc_deadline_state_init(exec_ctx, elem, args->call_stack);
calld->path = GRPC_MDSTR_REF(args->path);
calld->call_start_time = args->start_time;
calld->deadline = gpr_convert_clock_type(args->deadline, GPR_CLOCK_MONOTONIC);
calld->wait_for_ready_from_service_config = WAIT_FOR_READY_UNSET;
calld->cancel_error = GRPC_ERROR_NONE;
gpr_atm_rel_store(&calld->subchannel_call, 0);
gpr_mu_init(&calld->mu);
calld->connected_subchannel = NULL;
calld->waiting_ops = NULL;
calld->waiting_ops_count = 0;
calld->waiting_ops_capacity = 0;
calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
calld->owning_call = args->call_stack;
calld->pollent = NULL;
// If the resolver has already returned results, then we can access
// the service config parameters immediately. Otherwise, we need to
// defer that work until the resolver returns an initial result.
// TODO(roth): This code is almost but not quite identical to the code
// in read_service_config() above. It would be nice to find a way to
// combine them, to avoid having to maintain it twice.
gpr_mu_lock(&chand->mu);
if (chand->lb_policy != NULL) {
// We already have a resolver result, so check for service config.
if (chand->method_params_table != NULL) {
grpc_mdstr_hash_table *method_params_table =
grpc_mdstr_hash_table_ref(chand->method_params_table);
gpr_mu_unlock(&chand->mu);
method_parameters *method_params =
grpc_method_config_table_get(method_params_table, args->path);
if (method_params != NULL) {
if (gpr_time_cmp(method_params->timeout,
gpr_time_0(GPR_CLOCK_MONOTONIC)) != 0) {
gpr_timespec per_method_deadline =
gpr_time_add(calld->call_start_time, method_params->timeout);
calld->deadline = gpr_time_min(calld->deadline, per_method_deadline);
}
if (method_params->wait_for_ready != WAIT_FOR_READY_UNSET) {
calld->wait_for_ready_from_service_config =
method_params->wait_for_ready;
}
}
grpc_mdstr_hash_table_unref(method_params_table);
} else {
gpr_mu_unlock(&chand->mu);
}
} else {
// We don't yet have a resolver result, so register a callback to
// get the service config data once the resolver returns.
// Take a reference to the call stack to be owned by the callback.
GRPC_CALL_STACK_REF(calld->owning_call, "read_service_config");
grpc_closure_init(&calld->read_service_config, read_service_config, elem);
grpc_closure_list_append(&chand->waiting_for_config_closures,
&calld->read_service_config, GRPC_ERROR_NONE);
gpr_mu_unlock(&chand->mu);
}
// Start the deadline timer with the current deadline value. If we
// do not yet have service config data, then the timer may be reset
// later.
grpc_deadline_state_start(exec_ctx, elem, calld->deadline);
return GRPC_ERROR_NONE;
}
// The logic here is fairly complicated, due to (a) the fact that we
// need to handle the case where we receive the send op before the
// initial metadata op, and (b) the need for efficiency, especially in
// the streaming case.
// TODO(ctiller): Explain this more thoroughly.
static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
grpc_call_element *elem,
grpc_transport_stream_op *op) {
call_data *calld = elem->call_data;
channel_data *chand = elem->channel_data;
GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
grpc_deadline_state_client_start_transport_stream_op(exec_ctx, elem, op);
/* try to (atomically) get the call */
grpc_subchannel_call *call = GET_CALL(calld);
GPR_TIMER_BEGIN("cc_start_transport_stream_op", 0);
if (call == CANCELLED_CALL) {
grpc_transport_stream_op_finish_with_failure(
exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error));
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
if (call != NULL) {
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
/* we failed; lock and figure out what to do */
gpr_mu_lock(&calld->mu);
retry:
/* need to recheck that another thread hasn't set the call */
call = GET_CALL(calld);
if (call == CANCELLED_CALL) {
gpr_mu_unlock(&calld->mu);
grpc_transport_stream_op_finish_with_failure(
exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error));
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
if (call != NULL) {
gpr_mu_unlock(&calld->mu);
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
/* if this is a cancellation, then we can raise our cancelled flag */
if (op->cancel_error != GRPC_ERROR_NONE) {
if (!gpr_atm_rel_cas(&calld->subchannel_call, 0,
(gpr_atm)(uintptr_t)CANCELLED_CALL)) {
goto retry;
} else {
// Stash a copy of cancel_error in our call data, so that we can use
// it for subsequent operations. This ensures that if the call is
// cancelled before any ops are passed down (e.g., if the deadline
// is in the past when the call starts), we can return the right
// error to the caller when the first op does get passed down.
calld->cancel_error = GRPC_ERROR_REF(op->cancel_error);
switch (calld->creation_phase) {
case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING:
fail_locked(exec_ctx, calld, GRPC_ERROR_REF(op->cancel_error));
break;
case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL:
pick_subchannel(exec_ctx, elem, NULL, 0, &calld->connected_subchannel,
NULL, GRPC_ERROR_REF(op->cancel_error));
break;
}
gpr_mu_unlock(&calld->mu);
grpc_transport_stream_op_finish_with_failure(
exec_ctx, op, GRPC_ERROR_REF(op->cancel_error));
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
}
/* if we don't have a subchannel, try to get one */
if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
calld->connected_subchannel == NULL &&
op->send_initial_metadata != NULL) {
calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
grpc_closure_init(&calld->next_step, subchannel_ready, elem);
GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel");
/* If a subchannel is not available immediately, the polling entity from
call_data should be provided to channel_data's interested_parties, so
that IO of the lb_policy and resolver could be done under it. */
if (pick_subchannel(exec_ctx, elem, op->send_initial_metadata,
op->send_initial_metadata_flags,
&calld->connected_subchannel, &calld->next_step,
GRPC_ERROR_NONE)) {
calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel");
} else {
grpc_polling_entity_add_to_pollset_set(exec_ctx, calld->pollent,
chand->interested_parties);
}
}
/* if we've got a subchannel, then let's ask it to create a call */
if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
calld->connected_subchannel != NULL) {
grpc_subchannel_call *subchannel_call = NULL;
grpc_error *error = grpc_connected_subchannel_create_call(
exec_ctx, calld->connected_subchannel, calld->pollent, calld->path,
calld->deadline, &subchannel_call);
if (error != GRPC_ERROR_NONE) {
subchannel_call = CANCELLED_CALL;
fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error));
grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
}
gpr_atm_rel_store(&calld->subchannel_call,
(gpr_atm)(uintptr_t)subchannel_call);
retry_waiting_locked(exec_ctx, calld);
goto retry;
}
/* nothing to be done but wait */
add_waiting_locked(calld, op);
gpr_mu_unlock(&calld->mu);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
}
// The logic here is fairly complicated, due to (a) the fact that we
// need to handle the case where we receive the send op before the
// initial metadata op, and (b) the need for efficiency, especially in
// the streaming case.
// TODO(ctiller): Explain this more thoroughly.
static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
grpc_call_element *elem,
grpc_transport_stream_op *op) {
call_data *calld = elem->call_data;
GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
/* try to (atomically) get the call */
grpc_subchannel_call *call = GET_CALL(calld);
GPR_TIMER_BEGIN("cc_start_transport_stream_op", 0);
if (call == CANCELLED_CALL) {
grpc_transport_stream_op_finish_with_failure(exec_ctx, op,
GRPC_ERROR_CANCELLED);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
if (call != NULL) {
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
/* we failed; lock and figure out what to do */
gpr_mu_lock(&calld->mu);
retry:
/* need to recheck that another thread hasn't set the call */
call = GET_CALL(calld);
if (call == CANCELLED_CALL) {
gpr_mu_unlock(&calld->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op,
GRPC_ERROR_CANCELLED);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
if (call != NULL) {
gpr_mu_unlock(&calld->mu);
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
/* if this is a cancellation, then we can raise our cancelled flag */
if (op->cancel_error != GRPC_ERROR_NONE) {
if (!gpr_atm_rel_cas(&calld->subchannel_call, 0,
(gpr_atm)(uintptr_t)CANCELLED_CALL)) {
goto retry;
} else {
switch (calld->creation_phase) {
case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING:
fail_locked(exec_ctx, calld, GRPC_ERROR_REF(op->cancel_error));
break;
case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL:
pick_subchannel(exec_ctx, elem, NULL, 0, &calld->connected_subchannel,
NULL);
break;
}
gpr_mu_unlock(&calld->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op,
GRPC_ERROR_CANCELLED);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
return;
}
}
/* if we don't have a subchannel, try to get one */
if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
calld->connected_subchannel == NULL &&
op->send_initial_metadata != NULL) {
calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
grpc_closure_init(&calld->next_step, subchannel_ready, calld);
GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel");
if (pick_subchannel(exec_ctx, elem, op->send_initial_metadata,
op->send_initial_metadata_flags,
&calld->connected_subchannel, &calld->next_step)) {
calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel");
}
}
/* if we've got a subchannel, then let's ask it to create a call */
if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
calld->connected_subchannel != NULL) {
grpc_subchannel_call *subchannel_call = NULL;
grpc_error *error = grpc_connected_subchannel_create_call(
exec_ctx, calld->connected_subchannel, calld->pollent,
&subchannel_call);
if (error != GRPC_ERROR_NONE) {
subchannel_call = CANCELLED_CALL;
fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error));
grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
}
gpr_atm_rel_store(&calld->subchannel_call,
(gpr_atm)(uintptr_t)subchannel_call);
retry_waiting_locked(exec_ctx, calld);
goto retry;
}
/* nothing to be done but wait */
add_waiting_locked(calld, op);
gpr_mu_unlock(&calld->mu);
GPR_TIMER_END("cc_start_transport_stream_op", 0);
}
void grpc_subchannel_call_holder_perform_op(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder,
grpc_transport_stream_op *op) {
/* try to (atomically) get the call */
grpc_subchannel_call *call = GET_CALL(holder);
GPR_TIMER_BEGIN("grpc_subchannel_call_holder_perform_op", 0);
if (call == CANCELLED_CALL) {
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
if (call != NULL) {
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
/* we failed; lock and figure out what to do */
gpr_mu_lock(&holder->mu);
retry:
/* need to recheck that another thread hasn't set the call */
call = GET_CALL(holder);
if (call == CANCELLED_CALL) {
gpr_mu_unlock(&holder->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
if (call != NULL) {
gpr_mu_unlock(&holder->mu);
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
/* if this is a cancellation, then we can raise our cancelled flag */
if (op->cancel_with_status != GRPC_STATUS_OK) {
if (!gpr_atm_rel_cas(&holder->subchannel_call, 0, 1)) {
goto retry;
} else {
switch (holder->creation_phase) {
case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING:
fail_locked(exec_ctx, holder);
break;
case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL:
holder->pick_subchannel(exec_ctx, holder->pick_subchannel_arg, NULL,
&holder->connected_subchannel, NULL);
break;
}
gpr_mu_unlock(&holder->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
}
/* if we don't have a subchannel, try to get one */
if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
holder->connected_subchannel == NULL &&
op->send_initial_metadata != NULL) {
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
grpc_closure_init(&holder->next_step, subchannel_ready, holder);
GRPC_CALL_STACK_REF(holder->owning_call, "pick_subchannel");
if (holder->pick_subchannel(
exec_ctx, holder->pick_subchannel_arg, op->send_initial_metadata,
&holder->connected_subchannel, &holder->next_step)) {
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
GRPC_CALL_STACK_UNREF(exec_ctx, holder->owning_call, "pick_subchannel");
}
}
/* if we've got a subchannel, then let's ask it to create a call */
if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
holder->connected_subchannel != NULL) {
gpr_atm_rel_store(
&holder->subchannel_call,
(gpr_atm)(uintptr_t)grpc_connected_subchannel_create_call(
exec_ctx, holder->connected_subchannel, holder->pollset));
retry_waiting_locked(exec_ctx, holder);
goto retry;
}
/* nothing to be done but wait */
add_waiting_locked(holder, op);
gpr_mu_unlock(&holder->mu);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
}
