void gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n) {
gpr_atm_no_barrier_store(&n->next, (gpr_atm)NULL);
gpr_mpscq_node *prev =
(gpr_mpscq_node *)gpr_atm_full_xchg(&q->head, (gpr_atm)n);
gpr_atm_rel_store(&prev->next, (gpr_atm)n);
}
static void compress_start_transport_stream_op_batch(
grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
grpc_transport_stream_op_batch *op) {
call_data *calld = elem->call_data;
GPR_TIMER_BEGIN("compress_start_transport_stream_op_batch", 0);
if (op->cancel_stream) {
GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error);
gpr_atm cur = gpr_atm_full_xchg(
&calld->send_initial_metadata_state,
CANCELLED_BIT | (gpr_atm)op->payload->cancel_stream.cancel_error);
switch (cur) {
case HAS_COMPRESSION_ALGORITHM:
case NO_COMPRESSION_ALGORITHM:
case INITIAL_METADATA_UNSEEN:
break;
default:
if ((cur & CANCELLED_BIT) == 0) {
grpc_transport_stream_op_batch_finish_with_failure(
exec_ctx, (grpc_transport_stream_op_batch *)cur,
GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error));
} else {
GRPC_ERROR_UNREF((grpc_error *)(cur & ~CANCELLED_BIT));
}
break;
}
}
if (op->send_initial_metadata) {
bool has_compression_algorithm;
grpc_error *error = process_send_initial_metadata(
exec_ctx, elem,
op->payload->send_initial_metadata.send_initial_metadata,
&has_compression_algorithm);
if (error != GRPC_ERROR_NONE) {
grpc_transport_stream_op_batch_finish_with_failure(exec_ctx, op, error);
return;
}
gpr_atm cur;
retry_send_im:
cur = gpr_atm_acq_load(&calld->send_initial_metadata_state);
GPR_ASSERT(cur != HAS_COMPRESSION_ALGORITHM &&
cur != NO_COMPRESSION_ALGORITHM);
if ((cur & CANCELLED_BIT) == 0) {
if (!gpr_atm_rel_cas(&calld->send_initial_metadata_state, cur,
has_compression_algorithm
? HAS_COMPRESSION_ALGORITHM
: NO_COMPRESSION_ALGORITHM)) {
goto retry_send_im;
}
if (cur != INITIAL_METADATA_UNSEEN) {
grpc_call_next_op(exec_ctx, elem,
(grpc_transport_stream_op_batch *)cur);
}
}
}
if (op->send_message) {
gpr_atm cur;
retry_send:
cur = gpr_atm_acq_load(&calld->send_initial_metadata_state);
switch (cur) {
case INITIAL_METADATA_UNSEEN:
if (!gpr_atm_rel_cas(&calld->send_initial_metadata_state, cur,
(gpr_atm)op)) {
goto retry_send;
}
break;
case HAS_COMPRESSION_ALGORITHM:
case NO_COMPRESSION_ALGORITHM:
if (!skip_compression(elem,
op->payload->send_message.send_message->flags,
cur == HAS_COMPRESSION_ALGORITHM)) {
calld->send_op = op;
calld->send_length = op->payload->send_message.send_message->length;
calld->send_flags = op->payload->send_message.send_message->flags;
continue_send_message(exec_ctx, elem);
} else {
/* pass control down the stack */
grpc_call_next_op(exec_ctx, elem, op);
}
break;
default:
if (cur & CANCELLED_BIT) {
grpc_transport_stream_op_batch_finish_with_failure(
exec_ctx, op,
GRPC_ERROR_REF((grpc_error *)(cur & ~CANCELLED_BIT)));
} else {
/* >1 send_message concurrently */
GPR_UNREACHABLE_CODE(break);
}
}
} else {
