Introduce the (outside-of-iomgr) pollset API.

This CL introduces the public side of this interface. There will need to be an
iomgr-private API also, but this will be a per-implementation API and so is not
covered here.

I've taken care of wiring the interface through the codebase in the manner that
I expect it will be used.
	Change on 2014/12/17 by ctiller <ctiller@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82376987

18 files changed, 164 insertions, 11 deletions

diff --git a/src/core/channel/call_op_string.c b/src/core/channel/call_op_string.c
index 4a98cbfbbb..9a7838ce2f 100644
--- a/src/core/channel/call_op_string.c
+++ b/src/core/channel/call_op_string.c
@@ -107,7 +107,7 @@ char *grpc_call_op_string(grpc_call_op *op) {
               op->data.deadline.tv_nsec);
       break;
     case GRPC_SEND_START:
-      bprintf(&b, "SEND_START");
+      bprintf(&b, "SEND_START pollset=%p", op->data.start.pollset);
       break;
     case GRPC_SEND_MESSAGE:
       bprintf(&b, "SEND_MESSAGE");
diff --git a/src/core/channel/channel_stack.h b/src/core/channel/channel_stack.h
index b837caf97b..14e972f539 100644
--- a/src/core/channel/channel_stack.h
+++ b/src/core/channel/channel_stack.h
@@ -108,6 +108,9 @@ typedef struct {
 
   /* Argument data, matching up with grpc_call_op_type names */
   union {
+    struct {
+      grpc_pollset *pollset;
+    } start;
     grpc_byte_buffer *message;
     grpc_mdelem *metadata;
     gpr_timespec deadline;
diff --git a/src/core/channel/client_channel.c b/src/core/channel/client_channel.c
index a146a7b6a0..6329932330 100644
--- a/src/core/channel/client_channel.c
+++ b/src/core/channel/client_channel.c
@@ -98,6 +98,7 @@ struct call_data {
       void (*on_complete)(void *user_data, grpc_op_error error);
       void *on_complete_user_data;
       gpr_uint32 start_flags;
+      grpc_pollset *pollset;
     } waiting;
   } s;
 };
@@ -186,6 +187,7 @@ static void start_rpc(grpc_call_element *elem, grpc_call_op *op) {
     calld->s.waiting.on_complete = op->done_cb;
     calld->s.waiting.on_complete_user_data = op->user_data;
     calld->s.waiting.start_flags = op->flags;
+    calld->s.waiting.pollset = op->data.start.pollset;
     chand->waiting_children[chand->waiting_child_count++] = calld;
     gpr_mu_unlock(&chand->mu);
 
@@ -523,6 +525,7 @@ grpc_transport_setup_result grpc_client_channel_transport_setup_complete(
     call_ops[i].done_cb = waiting_children[i]->s.waiting.on_complete;
     call_ops[i].user_data =
         waiting_children[i]->s.waiting.on_complete_user_data;
+    call_ops[i].data.start.pollset = waiting_children[i]->s.waiting.pollset;
     if (!prepare_activate(waiting_children[i]->elem, chand->active_child)) {
       waiting_children[i] = NULL;
       call_ops[i].done_cb(call_ops[i].user_data, GRPC_OP_ERROR);
diff --git a/src/core/channel/connected_channel.c b/src/core/channel/connected_channel.c
index 8581fb41d6..5faa03c2f4 100644
--- a/src/core/channel/connected_channel.c
+++ b/src/core/channel/connected_channel.c
@@ -132,6 +132,7 @@ static void call_op(grpc_call_element *elem, grpc_call_element *from_elem,
                                 op->user_data);
       break;
     case GRPC_SEND_START:
+      grpc_transport_add_to_pollset(chand->transport, op->data.start.pollset);
       grpc_sopb_add_metadata_boundary(&calld->outgoing_sopb);
       end_bufferable_op(op, chand, calld, 0);
       break;
diff --git a/src/core/iomgr/endpoint.c b/src/core/iomgr/endpoint.c
index 259c948720..f1944bf672 100644
--- a/src/core/iomgr/endpoint.c
+++ b/src/core/iomgr/endpoint.c
@@ -44,6 +44,10 @@ grpc_endpoint_write_status grpc_endpoint_write(
   return ep->vtable->write(ep, slices, nslices, cb, user_data, deadline);
 }
 
+void grpc_endpoint_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset) {
+  ep->vtable->add_to_pollset(ep, pollset);
+}
+
 void grpc_endpoint_shutdown(grpc_endpoint *ep) { ep->vtable->shutdown(ep); }
 
 void grpc_endpoint_destroy(grpc_endpoint *ep) { ep->vtable->destroy(ep); }
diff --git a/src/core/iomgr/endpoint.h b/src/core/iomgr/endpoint.h
index 88949fb03f..bbd800bea8 100644
--- a/src/core/iomgr/endpoint.h
+++ b/src/core/iomgr/endpoint.h
@@ -34,6 +34,7 @@
 #ifndef __GRPC_INTERNAL_IOMGR_ENDPOINT_H__
 #define __GRPC_INTERNAL_IOMGR_ENDPOINT_H__
 
+#include "src/core/iomgr/pollset.h"
 #include <grpc/support/slice.h>
 #include <grpc/support/time.h>
 
@@ -69,6 +70,7 @@ struct grpc_endpoint_vtable {
   grpc_endpoint_write_status (*write)(grpc_endpoint *ep, gpr_slice *slices,
                                       size_t nslices, grpc_endpoint_write_cb cb,
                                       void *user_data, gpr_timespec deadline);
+  void (*add_to_pollset)(grpc_endpoint *ep, grpc_pollset *pollset);
   void (*shutdown)(grpc_endpoint *ep);
   void (*destroy)(grpc_endpoint *ep);
 };
@@ -92,6 +94,10 @@ grpc_endpoint_write_status grpc_endpoint_write(
 void grpc_endpoint_shutdown(grpc_endpoint *ep);
 void grpc_endpoint_destroy(grpc_endpoint *ep);
 
+/* Add an endpoint to a pollset, so that when the pollset is polled, events from
+   this endpoint are considered */
+void grpc_endpoint_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset);
+
 struct grpc_endpoint {
   const grpc_endpoint_vtable *vtable;
 };
diff --git a/src/core/iomgr/pollset.c b/src/core/iomgr/pollset.c
new file mode 100644
index 0000000000..62a0019eb3
--- /dev/null
+++ b/src/core/iomgr/pollset.c
@@ -0,0 +1,37 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/iomgr/pollset.h"
+
+void grpc_pollset_init(grpc_pollset *pollset) { pollset->unused = 0; }
+void grpc_pollset_destroy(grpc_pollset *pollset) {}
diff --git a/src/core/iomgr/pollset.h b/src/core/iomgr/pollset.h
new file mode 100644
index 0000000000..ba1a9d5429
--- /dev/null
+++ b/src/core/iomgr/pollset.h
@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_H_
+#define __GRPC_INTERNAL_IOMGR_POLLSET_H_
+
+/* A grpc_pollset is a set of file descriptors that a higher level item is
+   interested in. For example:
+    - a server will typically keep a pollset containing all connected channels,
+      so that it can find new calls to service
+    - a completion queue might keep a pollset with an entry for each transport
+      that is servicing a call that it's tracking */
+/* Eventually different implementations of iomgr will provide their own
+   grpc_pollset structs. As this is just a dummy wrapper to get the API in,
+   we just define a simple type here. */
+typedef struct { char unused; } grpc_pollset;
+
+void grpc_pollset_init(grpc_pollset *pollset);
+void grpc_pollset_destroy(grpc_pollset *pollset);
+
+#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_H_ */
diff --git a/src/core/iomgr/tcp_posix.c b/src/core/iomgr/tcp_posix.c
index b59e916e13..bc3ce69e47 100644
--- a/src/core/iomgr/tcp_posix.c
+++ b/src/core/iomgr/tcp_posix.c
@@ -538,9 +538,14 @@ static grpc_endpoint_write_status grpc_tcp_write(
   return status;
 }
 
-static const grpc_endpoint_vtable vtable = {grpc_tcp_notify_on_read,
-                                            grpc_tcp_write, grpc_tcp_shutdown,
-                                            grpc_tcp_destroy};
+static void grpc_tcp_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset) {
+  /* tickle the pollset so we crash if things aren't wired correctly */
+  pollset->unused++;
+}
+
+static const grpc_endpoint_vtable vtable = {
+    grpc_tcp_notify_on_read, grpc_tcp_write, grpc_tcp_add_to_pollset,
+    grpc_tcp_shutdown, grpc_tcp_destroy};
 
 grpc_endpoint *grpc_tcp_create(grpc_fd *em_fd, size_t slice_size) {
   grpc_tcp *tcp = (grpc_tcp *)gpr_malloc(sizeof(grpc_tcp));
diff --git a/src/core/security/secure_endpoint.c b/src/core/security/secure_endpoint.c
index 34be4256a9..cab09ca49d 100644
--- a/src/core/security/secure_endpoint.c
+++ b/src/core/security/secure_endpoint.c
@@ -325,8 +325,15 @@ static void endpoint_unref(grpc_endpoint *secure_ep) {
   secure_endpoint_unref(ep);
 }
 
+static void endpoint_add_to_pollset(grpc_endpoint *secure_ep,
+                                    grpc_pollset *pollset) {
+  secure_endpoint *ep = (secure_endpoint *)secure_ep;
+  grpc_endpoint_add_to_pollset(ep->wrapped_ep, pollset);
+}
+
 static const grpc_endpoint_vtable vtable = {
-    endpoint_notify_on_read, endpoint_write, endpoint_shutdown, endpoint_unref};
+    endpoint_notify_on_read, endpoint_write, endpoint_add_to_pollset,
+    endpoint_shutdown, endpoint_unref};
 
 grpc_endpoint *grpc_secure_endpoint_create(
     struct tsi_frame_protector *protector, grpc_endpoint *transport,
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index ba4c806602..6270ce640d 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -409,6 +409,7 @@ grpc_call_error grpc_call_start_invoke(grpc_call *call,
   op.dir = GRPC_CALL_DOWN;
   op.flags = flags;
   op.done_cb = done_invoke;
+  op.data.start.pollset = grpc_cq_pollset(cq);
   op.user_data = call;
 
   elem = CALL_ELEM_FROM_CALL(call, 0);
@@ -480,6 +481,7 @@ grpc_call_error grpc_call_server_end_initial_metadata(grpc_call *call,
   op.dir = GRPC_CALL_DOWN;
   op.flags = flags;
   op.done_cb = do_nothing;
+  op.data.start.pollset = grpc_cq_pollset(call->cq);
   op.user_data = NULL;
 
   elem = CALL_ELEM_FROM_CALL(call, 0);
diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index b890f9dab7..4837f5b978 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -66,6 +66,8 @@ struct grpc_completion_queue {
   /* When refs drops to zero, we are in shutdown mode, and will be destroyable
      once all queued events are drained */
   gpr_refcount refs;
+  /* the set of low level i/o things that concern this cq */
+  grpc_pollset pollset;
   /* 0 initially, 1 once we've begun shutting down */
   int shutdown;
   /* Head of a linked list of queued events (prev points to the last element) */
@@ -87,6 +89,7 @@ grpc_completion_queue *grpc_completion_queue_create() {
   memset(cc, 0, sizeof(*cc));
   /* Initial ref is dropped by grpc_completion_queue_shutdown */
   gpr_ref_init(&cc->refs, 1);
+  grpc_pollset_init(&cc->pollset);
   cc->allow_polling = 1;
   return cc;
 }
@@ -367,6 +370,7 @@ void grpc_completion_queue_shutdown(grpc_completion_queue *cc) {
 
 void grpc_completion_queue_destroy(grpc_completion_queue *cc) {
   GPR_ASSERT(cc->queue == NULL);
+  grpc_pollset_destroy(&cc->pollset);
   gpr_free(cc);
 }
 
@@ -392,3 +396,7 @@ void grpc_cq_dump_pending_ops(grpc_completion_queue *cc) {
   gpr_log(GPR_INFO, "pending ops:%s", tmp);
 #endif
 }
+
+grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc) {
+  return &cc->pollset;
+}
diff --git a/src/core/surface/completion_queue.h b/src/core/surface/completion_queue.h
index 8f3d34ab31..2e752a3fe0 100644
--- a/src/core/surface/completion_queue.h
+++ b/src/core/surface/completion_queue.h
@@ -36,6 +36,7 @@
 
 /* Internal API for completion channels */
 
+#include "src/core/iomgr/pollset.h"
 #include <grpc/grpc.h>
 
 /* A finish func is executed whenever the event consumer calls
@@ -101,4 +102,6 @@ void grpc_completion_queue_dont_poll_test_only(grpc_completion_queue *cc);
 
 void grpc_cq_dump_pending_ops(grpc_completion_queue *cc);
 
+grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);
+
 #endif  /* __GRPC_INTERNAL_SURFACE_COMPLETION_QUEUE_H__ */
diff --git a/src/core/surface/server.c b/src/core/surface/server.c
index 9eaa3c0602..3829e7aa8f 100644
--- a/src/core/surface/server.c
+++ b/src/core/surface/server.c
@@ -491,6 +491,8 @@ grpc_transport_setup_result grpc_server_setup_transport(
   }
   filters[i] = &grpc_connected_channel_filter;
 
+  grpc_transport_add_to_pollset(transport, grpc_cq_pollset(s->cq));
+
   channel = grpc_channel_create_from_filters(filters, num_filters,
                                              s->channel_args, mdctx, 0);
   chand = (channel_data *)grpc_channel_stack_element(
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index 0570439813..a8ae8cc5bc 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -1696,14 +1696,23 @@ static void run_callbacks(transport *t) {
   }
 }
 
+static void add_to_pollset(grpc_transport *gt, grpc_pollset *pollset) {
+  transport *t = (transport *)gt;
+  lock(t);
+  if (t->ep) {
+    grpc_endpoint_add_to_pollset(t->ep, pollset);
+  }
+  unlock(t);
+}
+
 /*
  * INTEGRATION GLUE
  */
 
 static const grpc_transport_vtable vtable = {
     sizeof(stream), init_stream, send_batch, set_allow_window_updates,
-    destroy_stream, abort_stream, goaway, close_transport, send_ping,
-    destroy_transport};
+    add_to_pollset, destroy_stream, abort_stream, goaway, close_transport,
+    send_ping, destroy_transport};
 
 void grpc_create_chttp2_transport(grpc_transport_setup_callback setup,
                                   void *arg,
diff --git a/src/core/transport/transport.c b/src/core/transport/transport.c
index 1c44abcadf..0ca67acb92 100644
--- a/src/core/transport/transport.c
+++ b/src/core/transport/transport.c
@@ -66,6 +66,11 @@ void grpc_transport_set_allow_window_updates(grpc_transport *transport,
   transport->vtable->set_allow_window_updates(transport, stream, allow);
 }
 
+void grpc_transport_add_to_pollset(grpc_transport *transport,
+                                   grpc_pollset *pollset) {
+  transport->vtable->add_to_pollset(transport, pollset);
+}
+
 void grpc_transport_destroy_stream(grpc_transport *transport,
                                    grpc_stream *stream) {
   transport->vtable->destroy_stream(transport, stream);
diff --git a/src/core/transport/transport.h b/src/core/transport/transport.h
index 6a089a2a15..00dacbf5b9 100644
--- a/src/core/transport/transport.h
+++ b/src/core/transport/transport.h
@@ -36,6 +36,7 @@
 
 #include <stddef.h>
 
+#include "src/core/iomgr/pollset.h"
 #include "src/core/transport/stream_op.h"
 
 /* forward declarations */
@@ -202,15 +203,18 @@ void grpc_transport_ping(grpc_transport *transport, void (*cb)(void *user_data),
 void grpc_transport_abort_stream(grpc_transport *transport, grpc_stream *stream,
                                  grpc_status_code status);
 
+void grpc_transport_add_to_pollset(grpc_transport *transport,
+                                   grpc_pollset *pollset);
+
 /* Advise peer of pending connection termination. */
-void grpc_transport_goaway(struct grpc_transport *transport,
-                           grpc_status_code status, gpr_slice debug_data);
+void grpc_transport_goaway(grpc_transport *transport, grpc_status_code status,
+                           gpr_slice debug_data);
 
 /* Close a transport. Aborts all open streams. */
-void grpc_transport_close(struct grpc_transport *transport);
+void grpc_transport_close(grpc_transport *transport);
 
 /* Destroy the transport */
-void grpc_transport_destroy(struct grpc_transport *transport);
+void grpc_transport_destroy(grpc_transport *transport);
 
 /* Return type for grpc_transport_setup_callback */
 typedef struct grpc_transport_setup_result {
diff --git a/src/core/transport/transport_impl.h b/src/core/transport/transport_impl.h
index 328ead2872..9f497b9cba 100644
--- a/src/core/transport/transport_impl.h
+++ b/src/core/transport/transport_impl.h
@@ -53,6 +53,9 @@ typedef struct grpc_transport_vtable {
   void (*set_allow_window_updates)(grpc_transport *self, grpc_stream *stream,
                                    int allow);
 
+  /* implementation of grpc_transport_add_to_pollset */
+  void (*add_to_pollset)(grpc_transport *self, grpc_pollset *pollset);
+
   /* implementation of grpc_transport_destroy_stream */
   void (*destroy_stream)(grpc_transport *self, grpc_stream *stream);