Initial checkin of gRPC to third_party/

third_party/grpc/src/core/surface/channel_connectivity.c

+/*
+ *
+ * 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/surface/channel.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/channel/client_channel.h"
+#include "src/core/channel/client_uchannel.h"
+#include "src/core/iomgr/timer.h"
+#include "src/core/surface/api_trace.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));
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_connectivity_state state;
+  GRPC_API_TRACE(
+      "grpc_channel_check_connectivity_state(channel=%p, try_to_connect=%d)", 2,
+      (channel, try_to_connect));
+  if (client_channel_elem->filter == &grpc_client_channel_filter) {
+    state = grpc_client_channel_check_connectivity_state(
+        &exec_ctx, client_channel_elem, try_to_connect);
+    grpc_exec_ctx_finish(&exec_ctx);
+    return state;
+  }
+  if (client_channel_elem->filter == &grpc_client_uchannel_filter) {
+    state = grpc_client_uchannel_check_connectivity_state(
+        &exec_ctx, client_channel_elem, try_to_connect);
+    grpc_exec_ctx_finish(&exec_ctx);
+    return state;
+  }
+  gpr_log(GPR_ERROR,
+          "grpc_channel_check_connectivity_state called on something that is "
+          "not a (u)client channel, but '%s'",
+          client_channel_elem->filter->name);
+  grpc_exec_ctx_finish(&exec_ctx);
+  return GRPC_CHANNEL_FATAL_FAILURE;
+}
+
+typedef enum {
+  WAITING,
+  CALLING_BACK,
+  CALLING_BACK_AND_FINISHED,
+  CALLED_BACK
+} callback_phase;
+
+typedef struct {
+  gpr_mu mu;
+  callback_phase phase;
+  int success;
+  grpc_closure on_complete;
+  grpc_timer alarm;
+  grpc_connectivity_state state;
+  grpc_completion_queue *cq;
+  grpc_cq_completion completion_storage;
+  grpc_channel *channel;
+  void *tag;
+} state_watcher;
+
+static void delete_state_watcher(grpc_exec_ctx *exec_ctx, state_watcher *w) {
+  grpc_channel_element *client_channel_elem = grpc_channel_stack_last_element(
+      grpc_channel_get_channel_stack(w->channel));
+  if (client_channel_elem->filter == &grpc_client_channel_filter) {
+    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, w->channel,
+                                "watch_channel_connectivity");
+  } else if (client_channel_elem->filter == &grpc_client_uchannel_filter) {
+    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, w->channel,
+                                "watch_uchannel_connectivity");
+  } else {
+    abort();
+  }
+  gpr_mu_destroy(&w->mu);
+  gpr_free(w);
+}
+
+static void finished_completion(grpc_exec_ctx *exec_ctx, 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_UNREACHABLE_CODE(return );
+    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(exec_ctx, w);
+  }
+}
+
+static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
+                        int due_to_completion) {
+  int delete = 0;
+
+  if (due_to_completion) {
+    grpc_timer_cancel(exec_ctx, &w->alarm);
+  }
+
+  gpr_mu_lock(&w->mu);
+  if (due_to_completion) {
+    w->success = 1;
+  }
+  switch (w->phase) {
+    case WAITING:
+      w->phase = CALLING_BACK;
+      grpc_cq_end_op(exec_ctx, 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_UNREACHABLE_CODE(return );
+    case CALLED_BACK:
+      delete = 1;
+      break;
+  }
+  gpr_mu_unlock(&w->mu);
+
+  if (delete) {
+    delete_state_watcher(exec_ctx, w);
+  }
+}
+
+static void watch_complete(grpc_exec_ctx *exec_ctx, void *pw, bool success) {
+  partly_done(exec_ctx, pw, 1);
+}
+
+static void timeout_complete(grpc_exec_ctx *exec_ctx, void *pw, bool success) {
+  partly_done(exec_ctx, pw, 0);
+}
+
+void grpc_channel_watch_connectivity_state(
+    grpc_channel *channel, grpc_connectivity_state last_observed_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));
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  state_watcher *w = gpr_malloc(sizeof(*w));
+
+  GRPC_API_TRACE(
+      "grpc_channel_watch_connectivity_state("
+      "channel=%p, last_observed_state=%d, "
+      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "cq=%p, tag=%p)",
+      7, (channel, (int)last_observed_state, (long long)deadline.tv_sec,
+          (int)deadline.tv_nsec, (int)deadline.clock_type, cq, tag));
+
+  grpc_cq_begin_op(cq, tag);
+
+  gpr_mu_init(&w->mu);
+  grpc_closure_init(&w->on_complete, watch_complete, w);
+  w->phase = WAITING;
+  w->state = last_observed_state;
+  w->success = 0;
+  w->cq = cq;
+  w->tag = tag;
+  w->channel = channel;
+
+  grpc_timer_init(&exec_ctx, &w->alarm,
+                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
+                  timeout_complete, w, gpr_now(GPR_CLOCK_MONOTONIC));
+
+  if (client_channel_elem->filter == &grpc_client_channel_filter) {
+    GRPC_CHANNEL_INTERNAL_REF(channel, "watch_channel_connectivity");
+    grpc_client_channel_watch_connectivity_state(&exec_ctx, client_channel_elem,
+                                                 grpc_cq_pollset(cq), &w->state,
+                                                 &w->on_complete);
+  } else if (client_channel_elem->filter == &grpc_client_uchannel_filter) {
+    GRPC_CHANNEL_INTERNAL_REF(channel, "watch_uchannel_connectivity");
+    grpc_client_uchannel_watch_connectivity_state(
+        &exec_ctx, client_channel_elem, grpc_cq_pollset(cq), &w->state,
+        &w->on_complete);
+  }
+
+  grpc_exec_ctx_finish(&exec_ctx);
+}