Initial checkin of gRPC to third_party/

third_party/grpc/src/core/channel/client_uchannel.c

Index: third_party/grpc/src/core/channel/client_uchannel.c
diff --git a/third_party/grpc/src/core/channel/client_uchannel.c b/third_party/grpc/src/core/channel/client_uchannel.c
new file mode 100644
index 0000000000000000000000000000000000000000..83fcc3a87f52f644f81b6a801edf9eb3b7522fc9
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+++ b/third_party/grpc/src/core/channel/client_uchannel.c
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+/*
+ *
+ * Copyright 2015-2016, 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/channel/client_uchannel.h"
+
+#include <string.h>
+
+#include "src/core/census/grpc_filter.h"
+#include "src/core/channel/channel_args.h"
+#include "src/core/channel/client_channel.h"
+#include "src/core/channel/compress_filter.h"
+#include "src/core/channel/subchannel_call_holder.h"
+#include "src/core/iomgr/iomgr.h"
+#include "src/core/support/string.h"
+#include "src/core/surface/channel.h"
+#include "src/core/transport/connectivity_state.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
+
+/** Microchannel (uchannel) implementation: a lightweight channel without any
+ * load-balancing mechanisms meant for communication from within the core. */
+
+typedef struct client_uchannel_channel_data {
+  /** master channel - the grpc_channel instance that ultimately owns
+      this channel_data via its channel stack.
+      We occasionally use this to bump the refcount on the master channel
+      to keep ourselves alive through an asynchronous operation. */
+  grpc_channel_stack *owning_stack;
+
+  /** connectivity state being tracked */
+  grpc_connectivity_state_tracker state_tracker;
+
+  /** the subchannel wrapped by the microchannel */
+  grpc_connected_subchannel *connected_subchannel;
+
+  /** the callback used to stay subscribed to subchannel connectivity
+   * notifications */
+  grpc_closure connectivity_cb;
+
+  /** the current connectivity state of the wrapped subchannel */
+  grpc_connectivity_state subchannel_connectivity;
+
+  gpr_mu mu_state;
+} channel_data;
+
+typedef grpc_subchannel_call_holder call_data;
+
+static void monitor_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
+                               bool iomgr_success) {
+  channel_data *chand = arg;
+  grpc_connectivity_state_set(exec_ctx, &chand->state_tracker,
+                              chand->subchannel_connectivity,
+                              "uchannel_monitor_subchannel");
+  grpc_connected_subchannel_notify_on_state_change(
+      exec_ctx, chand->connected_subchannel, NULL,
+      &chand->subchannel_connectivity, &chand->connectivity_cb);
+}
+
+static char *cuc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
+  return grpc_subchannel_call_holder_get_peer(exec_ctx, elem->call_data);
+}
+
+static void cuc_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
+                                          grpc_call_element *elem,
+                                          grpc_transport_stream_op *op) {
+  GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
+  grpc_subchannel_call_holder_perform_op(exec_ctx, elem->call_data, op);
+}
+
+static void cuc_start_transport_op(grpc_exec_ctx *exec_ctx,
+                                   grpc_channel_element *elem,
+                                   grpc_transport_op *op) {
+  channel_data *chand = elem->channel_data;
+
+  grpc_exec_ctx_enqueue(exec_ctx, op->on_consumed, true, NULL);
+
+  GPR_ASSERT(op->set_accept_stream == false);
+  GPR_ASSERT(op->bind_pollset == NULL);
+
+  if (op->on_connectivity_state_change != NULL) {
+    grpc_connectivity_state_notify_on_state_change(
+        exec_ctx, &chand->state_tracker, op->connectivity_state,
+        op->on_connectivity_state_change);
+    op->on_connectivity_state_change = NULL;
+    op->connectivity_state = NULL;
+  }
+
+  if (op->disconnect) {
+    grpc_connectivity_state_set(exec_ctx, &chand->state_tracker,
+                                GRPC_CHANNEL_FATAL_FAILURE, "disconnect");
+  }
+}
+
+static int cuc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
+                               grpc_metadata_batch *initial_metadata,
+                               grpc_connected_subchannel **connected_subchannel,
+                               grpc_closure *on_ready) {
+  channel_data *chand = arg;
+  GPR_ASSERT(initial_metadata != NULL);
+  *connected_subchannel = chand->connected_subchannel;
+  return 1;
+}
+
+/* Constructor for call_data */
+static void cuc_init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+                               grpc_call_element_args *args) {
+  grpc_subchannel_call_holder_init(elem->call_data, cuc_pick_subchannel,
+                                   elem->channel_data, args->call_stack);
+}
+
+/* Destructor for call_data */
+static void cuc_destroy_call_elem(grpc_exec_ctx *exec_ctx,
+                                  grpc_call_element *elem) {
+  grpc_subchannel_call_holder_destroy(exec_ctx, elem->call_data);
+}
+
+/* Constructor for channel_data */
+static void cuc_init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                  grpc_channel_element *elem,
+                                  grpc_channel_element_args *args) {
+  channel_data *chand = elem->channel_data;
+  memset(chand, 0, sizeof(*chand));
+  grpc_closure_init(&chand->connectivity_cb, monitor_subchannel, chand);
+  GPR_ASSERT(args->is_last);
+  GPR_ASSERT(elem->filter == &grpc_client_uchannel_filter);
+  chand->owning_stack = args->channel_stack;
+  grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
+                               "client_uchannel");
+  gpr_mu_init(&chand->mu_state);
+}
+
+/* Destructor for channel_data */
+static void cuc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem) {
+  channel_data *chand = elem->channel_data;
+  /* cancel subscription */
+  grpc_connected_subchannel_notify_on_state_change(
+      exec_ctx, chand->connected_subchannel, NULL, NULL,
+      &chand->connectivity_cb);
+  grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker);
+  gpr_mu_destroy(&chand->mu_state);
+  GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, chand->connected_subchannel,
+                                  "uchannel");
+}
+
+static void cuc_set_pollset(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+                            grpc_pollset *pollset) {
+  call_data *calld = elem->call_data;
+  calld->pollset = pollset;
+}
+
+const grpc_channel_filter grpc_client_uchannel_filter = {
+    cuc_start_transport_stream_op, cuc_start_transport_op, sizeof(call_data),
+    cuc_init_call_elem, cuc_set_pollset, cuc_destroy_call_elem,
+    sizeof(channel_data), cuc_init_channel_elem, cuc_destroy_channel_elem,
+    cuc_get_peer, "client-uchannel",
+};
+
+grpc_connectivity_state grpc_client_uchannel_check_connectivity_state(
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect) {
+  channel_data *chand = elem->channel_data;
+  grpc_connectivity_state out;
+  gpr_mu_lock(&chand->mu_state);
+  out = grpc_connectivity_state_check(&chand->state_tracker);
+  gpr_mu_unlock(&chand->mu_state);
+  return out;
+}
+
+void grpc_client_uchannel_watch_connectivity_state(
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
+    grpc_connectivity_state *state, grpc_closure *on_complete) {
+  channel_data *chand = elem->channel_data;
+  gpr_mu_lock(&chand->mu_state);
+  grpc_connectivity_state_notify_on_state_change(
+      exec_ctx, &chand->state_tracker, state, on_complete);
+  gpr_mu_unlock(&chand->mu_state);
+}
+
+grpc_channel *grpc_client_uchannel_create(grpc_subchannel *subchannel,
+                                          grpc_channel_args *args) {
+  grpc_channel *channel = NULL;
+#define MAX_FILTERS 3
+  const grpc_channel_filter *filters[MAX_FILTERS];
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  size_t n = 0;
+
+  if (grpc_channel_args_is_census_enabled(args)) {
+    filters[n++] = &grpc_client_census_filter;
+  }
+  filters[n++] = &grpc_compress_filter;
+  filters[n++] = &grpc_client_uchannel_filter;
+  GPR_ASSERT(n <= MAX_FILTERS);
+
+  channel =
+      grpc_channel_create_from_filters(&exec_ctx, NULL, filters, n, args, 1);
+
+  return channel;
+}
+
+void grpc_client_uchannel_set_connected_subchannel(
+    grpc_channel *uchannel, grpc_connected_subchannel *connected_subchannel) {
+  grpc_channel_element *elem =
+      grpc_channel_stack_last_element(grpc_channel_get_channel_stack(uchannel));
+  channel_data *chand = elem->channel_data;
+  GPR_ASSERT(elem->filter == &grpc_client_uchannel_filter);
+  gpr_mu_lock(&chand->mu_state);
+  chand->connected_subchannel = connected_subchannel;
+  GRPC_CONNECTED_SUBCHANNEL_REF(connected_subchannel, "uchannel");
+  gpr_mu_unlock(&chand->mu_state);
+}