Cleanup http_server_filter.

1 files changed, 63 insertions, 72 deletions

diff --git a/src/core/ext/filters/http/server/http_server_filter.cc b/src/core/ext/filters/http/server/http_server_filter.cc
index c202015875..83b8c291bb 100644
--- a/src/core/ext/filters/http/server/http_server_filter.cc
+++ b/src/core/ext/filters/http/server/http_server_filter.cc
@@ -35,39 +35,33 @@
 #define EXPECTED_CONTENT_TYPE_LENGTH sizeof(EXPECTED_CONTENT_TYPE) - 1
 
 namespace {
+
 struct call_data {
   grpc_call_combiner* call_combiner;
 
+  // Outgoing headers to add to send_initial_metadata.
   grpc_linked_mdelem status;
   grpc_linked_mdelem content_type;
 
-  /* did this request come with path query containing request payload */
-  bool seen_path_with_query;
-  /* flag to ensure payload_bin is delivered only once */
-  bool payload_bin_delivered;
+  // If we see the recv_message contents in the GET query string, we
+  // store it here.
+  grpc_core::ManualConstructor<grpc_core::SliceBufferByteStream> read_stream;
+  bool have_read_stream;
 
+  // State for intercepting recv_initial_metadata.
+  grpc_closure recv_initial_metadata_ready;
+  grpc_closure* original_recv_initial_metadata_ready;
   grpc_metadata_batch* recv_initial_metadata;
   uint32_t* recv_initial_metadata_flags;
-  /** Closure to call when finished with the hs_on_recv hook */
-  grpc_closure* on_done_recv;
-  /** Closure to call when we retrieve read message from the path URI
-   */
-  grpc_closure* recv_message_ready;
-  grpc_closure* on_complete;
-  grpc_core::OrphanablePtr<grpc_core::ByteStream>* pp_recv_message;
-  grpc_core::ManualConstructor<grpc_core::SliceBufferByteStream> read_stream;
+  bool seen_recv_initial_metadata_ready;
 
-  /** Receive closures are chained: we inject this closure as the on_done_recv
-      up-call on transport_op, and remember to call our on_done_recv member
-      after handling it. */
-  grpc_closure hs_on_recv;
-  grpc_closure hs_on_complete;
-  grpc_closure hs_recv_message_ready;
+  // State for intercepting recv_message.
+  grpc_closure* original_recv_message_ready;
+  grpc_closure recv_message_ready;
+  grpc_core::OrphanablePtr<grpc_core::ByteStream>* recv_message;
+  bool seen_recv_message_ready;
 };
 
-struct channel_data {
-  uint8_t unused;
-};
 }  // namespace
 
 static grpc_error* server_filter_outgoing_metadata(grpc_call_element* elem,
@@ -235,7 +229,7 @@ static grpc_error* server_filter_incoming_metadata(grpc_call_element* elem,
               GRPC_SLICE_LENGTH(query_slice), k_url_safe));
       calld->read_stream.Init(&read_slice_buffer, 0);
       grpc_slice_buffer_destroy_internal(&read_slice_buffer);
-      calld->seen_path_with_query = true;
+      calld->have_read_stream = true;
       grpc_slice_unref_internal(query_slice);
     } else {
       gpr_log(GPR_ERROR, "GET request without QUERY");
@@ -266,49 +260,55 @@ static grpc_error* server_filter_incoming_metadata(grpc_call_element* elem,
   return error;
 }
 
-static void hs_on_recv(void* user_data, grpc_error* err) {
+static void recv_initial_metadata_ready(void* user_data, grpc_error* err) {
   grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
   call_data* calld = static_cast<call_data*>(elem->call_data);
+  calld->seen_recv_initial_metadata_ready = true;
   if (err == GRPC_ERROR_NONE) {
     err = server_filter_incoming_metadata(elem, calld->recv_initial_metadata);
+    if (calld->seen_recv_message_ready) {
+      // We've already seen the recv_message callback, but we previously
+      // deferred it, so we need to return it here.
+      // Replace the recv_message byte stream if needed.
+      if (calld->have_read_stream) {
+        calld->recv_message->reset(calld->read_stream.get());
+        calld->have_read_stream = false;
+      }
+      // Re-enter call combiner for original_recv_message_ready, since the
+      // surface code will release the call combiner for each callback it
+      // receives.
+      GRPC_CALL_COMBINER_START(
+          calld->call_combiner, calld->original_recv_message_ready,
+          GRPC_ERROR_REF(err),
+          "resuming recv_message_ready from recv_initial_metadata_ready");
+    }
   } else {
     GRPC_ERROR_REF(err);
   }
-  GRPC_CLOSURE_RUN(calld->on_done_recv, err);
-}
-
-static void hs_on_complete(void* user_data, grpc_error* err) {
-  grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  /* Call recv_message_ready if we got the payload via the path field */
-  if (calld->seen_path_with_query && calld->recv_message_ready != nullptr) {
-    calld->pp_recv_message->reset(
-        calld->payload_bin_delivered ? nullptr
-                                     : reinterpret_cast<grpc_core::ByteStream*>(
-                                           calld->read_stream.get()));
-    // Re-enter call combiner for recv_message_ready, since the surface
-    // code will release the call combiner for each callback it receives.
-    GRPC_CALL_COMBINER_START(calld->call_combiner, calld->recv_message_ready,
-                             GRPC_ERROR_REF(err),
-                             "resuming recv_message_ready from on_complete");
-    calld->recv_message_ready = nullptr;
-    calld->payload_bin_delivered = true;
-  }
-  GRPC_CLOSURE_RUN(calld->on_complete, GRPC_ERROR_REF(err));
+  GRPC_CLOSURE_RUN(calld->original_recv_initial_metadata_ready, err);
 }
 
-static void hs_recv_message_ready(void* user_data, grpc_error* err) {
+static void recv_message_ready(void* user_data, grpc_error* err) {
   grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
   call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (calld->seen_path_with_query) {
-    // Do nothing. This is probably a GET request, and payload will be
-    // returned in hs_on_complete callback.
+  calld->seen_recv_message_ready = true;
+  if (calld->seen_recv_initial_metadata_ready) {
+    // We've already seen the recv_initial_metadata callback, so
+    // replace the recv_message byte stream if needed and invoke the
+    // original recv_message callback immediately.
+    if (calld->have_read_stream) {
+      calld->recv_message->reset(calld->read_stream.get());
+      calld->have_read_stream = false;
+    }
+    GRPC_CLOSURE_RUN(calld->original_recv_message_ready, GRPC_ERROR_REF(err));
+  } else {
+    // We have not yet seen the recv_initial_metadata callback, so we
+    // need to wait to see if this is a GET request.
     // Note that we release the call combiner here, so that other
     // callbacks can run.
-    GRPC_CALL_COMBINER_STOP(calld->call_combiner,
-                            "pausing recv_message_ready until on_complete");
-  } else {
-    GRPC_CLOSURE_RUN(calld->recv_message_ready, GRPC_ERROR_REF(err));
+    GRPC_CALL_COMBINER_STOP(
+        calld->call_combiner,
+        "pausing recv_message_ready until recv_initial_metadata_ready");
   }
 }
 
@@ -343,23 +343,17 @@ static grpc_error* hs_mutate_op(grpc_call_element* elem,
         op->payload->recv_initial_metadata.recv_initial_metadata;
     calld->recv_initial_metadata_flags =
         op->payload->recv_initial_metadata.recv_flags;
-    calld->on_done_recv =
+    calld->original_recv_initial_metadata_ready =
         op->payload->recv_initial_metadata.recv_initial_metadata_ready;
     op->payload->recv_initial_metadata.recv_initial_metadata_ready =
-        &calld->hs_on_recv;
+        &calld->recv_initial_metadata_ready;
   }
 
   if (op->recv_message) {
-    calld->recv_message_ready = op->payload->recv_message.recv_message_ready;
-    calld->pp_recv_message = op->payload->recv_message.recv_message;
-    if (op->payload->recv_message.recv_message_ready) {
-      op->payload->recv_message.recv_message_ready =
-          &calld->hs_recv_message_ready;
-    }
-    if (op->on_complete) {
-      calld->on_complete = op->on_complete;
-      op->on_complete = &calld->hs_on_complete;
-    }
+    calld->recv_message = op->payload->recv_message.recv_message;
+    calld->original_recv_message_ready =
+        op->payload->recv_message.recv_message_ready;
+    op->payload->recv_message.recv_message_ready = &calld->recv_message_ready;
   }
 
   if (op->send_trailing_metadata) {
@@ -387,15 +381,12 @@ static void hs_start_transport_stream_op_batch(
 /* Constructor for call_data */
 static grpc_error* init_call_elem(grpc_call_element* elem,
                                   const grpc_call_element_args* args) {
-  /* grab pointers to our data from the call element */
   call_data* calld = static_cast<call_data*>(elem->call_data);
-  /* initialize members */
   calld->call_combiner = args->call_combiner;
-  GRPC_CLOSURE_INIT(&calld->hs_on_recv, hs_on_recv, elem,
-                    grpc_schedule_on_exec_ctx);
-  GRPC_CLOSURE_INIT(&calld->hs_on_complete, hs_on_complete, elem,
+  GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
+                    recv_initial_metadata_ready, elem,
                     grpc_schedule_on_exec_ctx);
-  GRPC_CLOSURE_INIT(&calld->hs_recv_message_ready, hs_recv_message_ready, elem,
+  GRPC_CLOSURE_INIT(&calld->recv_message_ready, recv_message_ready, elem,
                     grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
@@ -405,7 +396,7 @@ static void destroy_call_elem(grpc_call_element* elem,
                               const grpc_call_final_info* final_info,
                               grpc_closure* ignored) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (calld->seen_path_with_query && !calld->payload_bin_delivered) {
+  if (calld->have_read_stream) {
     calld->read_stream->Orphan();
   }
 }
@@ -427,7 +418,7 @@ const grpc_channel_filter grpc_http_server_filter = {
     init_call_elem,
     grpc_call_stack_ignore_set_pollset_or_pollset_set,
     destroy_call_elem,
-    sizeof(channel_data),
+    0,
     init_channel_elem,
     destroy_channel_elem,
     grpc_channel_next_get_info,