Client connectivity API
Initial plumbing work; needs tests and more client_channel
implementation.
diff --git a/src/core/surface/channel_connectivity.c b/src/core/surface/channel_connectivity.c
new file mode 100644
index 0000000..bdd9678
--- /dev/null
+++ b/src/core/surface/channel_connectivity.c
@@ -0,0 +1,182 @@
+/*
+ *
+ * Copyright 2015, 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/surface/channel.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/channel/client_channel.h"
+#include "src/core/iomgr/alarm.h"
+#include "src/core/surface/completion_queue.h"
+
+grpc_connectivity_state grpc_channel_check_connectivity_state(
+ grpc_channel *channel, int try_to_connect) {
+ /* forward through to the underlying client channel */
+ grpc_channel_element *client_channel_elem =
+ grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
+ if (client_channel_elem->filter != &grpc_client_channel_filter) {
+ gpr_log(GPR_ERROR,
+ "grpc_channel_check_connectivity_state called on something that is "
+ "not a client channel, but '%s'",
+ client_channel_elem->filter->name);
+ return GRPC_CHANNEL_FATAL_FAILURE;
+ }
+ return grpc_client_channel_check_connectivity_state(client_channel_elem,
+ try_to_connect);
+}
+
+typedef enum {
+ WAITING,
+ CALLING_BACK,
+ CALLING_BACK_AND_FINISHED,
+ CALLED_BACK
+} callback_phase;
+
+typedef struct {
+ gpr_mu mu;
+ callback_phase phase;
+ int success;
+ grpc_iomgr_closure on_complete;
+ grpc_alarm alarm;
+ grpc_connectivity_state state;
+ grpc_connectivity_state *optional_new_state;
+ grpc_completion_queue *cq;
+ grpc_cq_completion completion_storage;
+ void *tag;
+} state_watcher;
+
+static void delete_state_watcher(state_watcher *w) {
+ gpr_mu_destroy(&w->mu);
+ gpr_free(w);
+}
+
+static void finished_completion(void *pw, grpc_cq_completion *ignored) {
+ int delete = 0;
+ state_watcher *w = pw;
+ gpr_mu_lock(&w->mu);
+ switch (w->phase) {
+ case WAITING:
+ case CALLED_BACK:
+ gpr_log(GPR_ERROR, "should never reach here");
+ abort();
+ break;
+ case CALLING_BACK:
+ w->phase = CALLED_BACK;
+ break;
+ case CALLING_BACK_AND_FINISHED:
+ delete = 1;
+ break;
+ }
+ gpr_mu_unlock(&w->mu);
+
+ if (delete) {
+ delete_state_watcher(w);
+ }
+}
+
+static void partly_done(state_watcher *w, int due_to_completion) {
+ int delete = 0;
+
+ if (due_to_completion) {
+ gpr_mu_lock(&w->mu);
+ w->success = 1;
+ gpr_mu_unlock(&w->mu);
+ grpc_alarm_cancel(&w->alarm);
+ }
+
+ gpr_mu_lock(&w->mu);
+ switch (w->phase) {
+ case WAITING:
+ w->phase = CALLING_BACK;
+ if (w->optional_new_state) {
+ *w->optional_new_state = w->state;
+ }
+ grpc_cq_end_op(w->cq, w->tag, w->success, finished_completion, w,
+ &w->completion_storage);
+ break;
+ case CALLING_BACK:
+ w->phase = CALLING_BACK_AND_FINISHED;
+ break;
+ case CALLING_BACK_AND_FINISHED:
+ gpr_log(GPR_ERROR, "should never reach here");
+ abort();
+ break;
+ case CALLED_BACK:
+ delete = 1;
+ break;
+ }
+ gpr_mu_unlock(&w->mu);
+
+ if (delete) {
+ delete_state_watcher(w);
+ }
+}
+
+static void watch_complete(void *pw, int success) { partly_done(pw, 0); }
+
+static void timeout_complete(void *pw, int success) { partly_done(pw, 1); }
+
+void grpc_channel_watch_connectivity_state(
+ grpc_channel *channel, grpc_connectivity_state last_observed_state,
+ grpc_connectivity_state *optional_new_state, gpr_timespec deadline,
+ grpc_completion_queue *cq, void *tag) {
+ grpc_channel_element *client_channel_elem =
+ grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
+ state_watcher *w = gpr_malloc(sizeof(*w));
+
+ grpc_cq_begin_op(cq);
+
+ gpr_mu_init(&w->mu);
+ grpc_iomgr_closure_init(&w->on_complete, watch_complete, w);
+ w->phase = WAITING;
+ w->state = last_observed_state;
+ w->success = 0;
+ w->optional_new_state = optional_new_state;
+ w->cq = cq;
+ w->tag = tag;
+
+ grpc_alarm_init(&w->alarm, deadline, timeout_complete, w,
+ gpr_now(GPR_CLOCK_REALTIME));
+
+ if (client_channel_elem->filter != &grpc_client_channel_filter) {
+ gpr_log(GPR_ERROR,
+ "grpc_channel_watch_connectivity_state called on something that is "
+ "not a client channel, but '%s'",
+ client_channel_elem->filter->name);
+ grpc_iomgr_add_delayed_callback(&w->on_complete, 1);
+ } else {
+ grpc_client_channel_watch_connectivity_state(client_channel_elem, &w->state,
+ &w->on_complete);
+ }
+}