Add explanation for recv_state
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 18a22e1..1ff2891 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -144,6 +144,9 @@
grpc_call *sibling_prev;
} child_call;
+#define RECV_NONE ((gpr_atm)0)
+#define RECV_INITIAL_METADATA_FIRST ((gpr_atm)1)
+
struct grpc_call {
gpr_refcount ext_ref;
gpr_arena *arena;
@@ -223,10 +226,23 @@
} server;
} final_op;
- // Either 0 (no initial metadata and messages received),
- // 1 (received initial metadata first)
- // or a batch_control* (received messages first, the lowest bit is 0)
- gpr_atm saved_receiving_stream_ready_bctlp;
+ /* recv_state can contain one of the following values:
+ RECV_NONE : : no initial metadata and messages received
+ RECV_INITIAL_METADATA_FIRST : received initial metadata first
+ a batch_control* : received messages first
+
+ +------1------RECV_NONE------3-----+
+ | |
+ | |
+ v v
+ RECV_INITIAL_METADATA_FIRST receiving_stream_ready_bctlp
+ | ^ | ^
+ | | | |
+ +-----2-----+ +-----4-----+
+
+ For 1, 4: See receiving_initial_metadata_ready() function
+ For 2, 3: See receiving_stream_ready() function */
+ gpr_atm recv_state;
};
grpc_tracer_flag grpc_call_error_trace =
@@ -1290,12 +1306,11 @@
cancel_with_error(exec_ctx, call, STATUS_FROM_SURFACE,
GRPC_ERROR_REF(error));
}
- /* If saved_receiving_stream_ready_bctlp is 0, we will save the batch_control
+ /* If recv_state is RECV_NONE, we will save the batch_control
* object with rel_cas, and will not use it after the cas. Its corresponding
* acq_load is in receiving_initial_metadata_ready() */
if (error != GRPC_ERROR_NONE || call->receiving_stream == NULL ||
- !gpr_atm_rel_cas(&call->saved_receiving_stream_ready_bctlp, 0,
- (gpr_atm)bctlp)) {
+ !gpr_atm_rel_cas(&call->recv_state, RECV_NONE, (gpr_atm)bctlp)) {
process_data_after_md(exec_ctx, bctlp);
}
}
@@ -1388,8 +1403,7 @@
grpc_closure *saved_rsr_closure = NULL;
while (true) {
- gpr_atm rsr_bctlp =
- gpr_atm_acq_load(&call->saved_receiving_stream_ready_bctlp);
+ gpr_atm rsr_bctlp = gpr_atm_acq_load(&call->recv_state);
/* Should only receive initial metadata once */
GPR_ASSERT(rsr_bctlp != 1);
if (rsr_bctlp == 0) {
@@ -1398,8 +1412,8 @@
* no_barrier_cas is used, as this function won't access the batch_control
* object saved by receiving_stream_ready() if the initial metadata is
* received first. */
- if (gpr_atm_no_barrier_cas(&call->saved_receiving_stream_ready_bctlp, 0,
- 1)) {
+ if (gpr_atm_no_barrier_cas(&call->recv_state, RECV_NONE,
+ RECV_INITIAL_METADATA_FIRST)) {
break;
}
} else {
@@ -1407,7 +1421,7 @@
saved_rsr_closure = GRPC_CLOSURE_CREATE(receiving_stream_ready,
(batch_control *)rsr_bctlp,
grpc_schedule_on_exec_ctx);
- /* No need to modify saved_receiving_stream_ready_bctlp */
+ /* No need to modify recv_state */
break;
}
}