Added flags support to grpc_op.

Which includes its propagation to grpc_ioreq and validation mechanisms for checking that only known bits are set ot in).
Also added an internal flag (GRPC_WRITE_INTERNAL_COMPRESS) mask for its use in signaling compressed messages.

3 files changed, 49 insertions, 2 deletions

diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index cead5e08dc..4b0a4c82f0 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -185,6 +185,7 @@ struct grpc_call {
      and a strong upper bound of a count of masters to be calculated. */
   gpr_uint8 request_set[GRPC_IOREQ_OP_COUNT];
   grpc_ioreq_data request_data[GRPC_IOREQ_OP_COUNT];
+  gpr_uint32 request_flags[GRPC_IOREQ_OP_COUNT];
   reqinfo_master masters[GRPC_IOREQ_OP_COUNT];
 
   /* Dynamic array of ioreq's that have completed: the count of
@@ -228,6 +229,7 @@ struct grpc_call {
 
   gpr_slice_buffer incoming_message;
   gpr_uint32 incoming_message_length;
+  gpr_uint32 incoming_message_flags;
   grpc_iomgr_closure destroy_closure;
 };
 
@@ -670,6 +672,7 @@ static int begin_message(grpc_call *call, grpc_begin_message msg) {
   } else if (msg.length > 0) {
     call->reading_message = 1;
     call->incoming_message_length = msg.length;
+    call->incoming_message_flags = msg.flags;
     return 1;
   } else {
     finish_message(call);
@@ -818,6 +821,7 @@ static void copy_byte_buffer_to_stream_ops(grpc_byte_buffer *byte_buffer,
 
 static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
   grpc_ioreq_data data;
+  gpr_uint32 flags;
   grpc_metadata_batch mdb;
   size_t i;
   GPR_ASSERT(op->send_ops == NULL);
@@ -844,8 +848,9 @@ static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
     case WRITE_STATE_STARTED:
       if (is_op_live(call, GRPC_IOREQ_SEND_MESSAGE)) {
         data = call->request_data[GRPC_IOREQ_SEND_MESSAGE];
+        flags = call->request_flags[GRPC_IOREQ_SEND_MESSAGE];
         grpc_sopb_add_begin_message(
-            &call->send_ops, grpc_byte_buffer_length(data.send_message), 0);
+            &call->send_ops, grpc_byte_buffer_length(data.send_message), flags);
         copy_byte_buffer_to_stream_ops(data.send_message, &call->send_ops);
         op->send_ops = &call->send_ops;
         call->last_send_contains |= 1 << GRPC_IOREQ_SEND_MESSAGE;
@@ -979,6 +984,7 @@ static grpc_call_error start_ioreq(grpc_call *call, const grpc_ioreq *reqs,
     have_ops |= 1u << op;
 
     call->request_data[op] = data;
+    call->request_flags[op] = reqs[i].flags;
     call->request_set[op] = set;
   }
 
@@ -1189,6 +1195,14 @@ static void finish_batch_with_close(grpc_call *call, int success, void *tag) {
   grpc_cq_end_op(call->cq, tag, call, 1);
 }
 
+static int are_write_flags_valid(gpr_uint32 flags) {
+  /* check that only bits in GRPC_WRITE_(INTERNAL?)_USED_MASK are set */
+  const gpr_uint32 allowed_write_positions =
+      (GRPC_WRITE_USED_MASK | GRPC_WRITE_INTERNAL_USED_MASK);
+  const gpr_uint32 invalid_positions = ~allowed_write_positions;
+  return !(flags & invalid_positions);
+}
+
 grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
                                       size_t nops, void *tag) {
   grpc_ioreq reqs[GRPC_IOREQ_OP_COUNT];
@@ -1211,30 +1225,43 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
     op = &ops[in];
     switch (op->op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_INITIAL_METADATA;
         req->data.send_metadata.count = op->data.send_initial_metadata.count;
         req->data.send_metadata.metadata =
             op->data.send_initial_metadata.metadata;
+        req->flags = op->flags;
         break;
       case GRPC_OP_SEND_MESSAGE:
+        if (!are_write_flags_valid(op->flags)){
+          return GRPC_CALL_ERROR_INVALID_FLAGS;
+        }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_MESSAGE;
         req->data.send_message = op->data.send_message;
+        req->flags = ops->flags;
         break;
       case GRPC_OP_SEND_CLOSE_FROM_CLIENT:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_CLOSE;
+        req->flags = op->flags;
         break;
       case GRPC_OP_SEND_STATUS_FROM_SERVER:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_CLIENT;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_TRAILING_METADATA;
+        req->flags = op->flags;
         req->data.send_metadata.count =
             op->data.send_status_from_server.trailing_metadata_count;
         req->data.send_metadata.metadata =
@@ -1248,24 +1275,33 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         req->op = GRPC_IOREQ_SEND_CLOSE;
         break;
       case GRPC_OP_RECV_INITIAL_METADATA:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_INITIAL_METADATA;
         req->data.recv_metadata = op->data.recv_initial_metadata;
+        req->flags = op->flags;
         break;
       case GRPC_OP_RECV_MESSAGE:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_MESSAGE;
         req->data.recv_message = op->data.recv_message;
+        req->flags = op->flags;
         break;
       case GRPC_OP_RECV_STATUS_ON_CLIENT:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_STATUS;
+        req->flags = op->flags;
         req->data.recv_status.set_value = set_status_value_directly;
         req->data.recv_status.user_data = op->data.recv_status_on_client.status;
         req = &reqs[out++];
@@ -1283,8 +1319,11 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         finish_func = finish_batch_with_close;
         break;
       case GRPC_OP_RECV_CLOSE_ON_SERVER:
+        /* Flag validation: currently allow no flags */
+        if (op->flags) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_STATUS;
+        req->flags = op->flags;
         req->data.recv_status.set_value = set_cancelled_value;
         req->data.recv_status.user_data =
             op->data.recv_close_on_server.cancelled;
diff --git a/src/core/surface/call.h b/src/core/surface/call.h
index 9116538948..7a14161253 100644
--- a/src/core/surface/call.h
+++ b/src/core/surface/call.h
@@ -79,6 +79,7 @@ typedef union {
 typedef struct {
   grpc_ioreq_op op;
   grpc_ioreq_data data;
+  gpr_uint32 flags;  /**< A copy of the write flags from grpc_op */
 } grpc_ioreq;
 
 typedef void (*grpc_ioreq_completion_func)(grpc_call *call, int success,
diff --git a/src/core/transport/stream_op.h b/src/core/transport/stream_op.h
index 5215cc87b1..e080701e2d 100644
--- a/src/core/transport/stream_op.h
+++ b/src/core/transport/stream_op.h
@@ -58,11 +58,18 @@ typedef enum grpc_stream_op_code {
   GRPC_OP_SLICE
 } grpc_stream_op_code;
 
+/** Internal bit flag for grpc_begin_message's \a flags signaling the use of
+ * compression for the message */
+#define GRPC_WRITE_INTERNAL_COMPRESS (0x80000000u)
+/** Mask of all valid internal flags. */
+#define GRPC_WRITE_INTERNAL_USED_MASK (GRPC_WRITE_INTERNAL_COMPRESS)
+
 /* Arguments for GRPC_OP_BEGIN_MESSAGE */
 typedef struct grpc_begin_message {
   /* How many bytes of data will this message contain */
   gpr_uint32 length;
-  /* Write flags for the message: see grpc.h GRPC_WRITE_xxx */
+  /* Write flags for the message: see grpc.h GRPC_WRITE_* for the public bits,
+   * GRPC_WRITE_INTERNAL_* for the internal ones. */
   gpr_uint32 flags;
 } grpc_begin_message;