Initial checkin of gRPC to third_party/

third_party/grpc/src/ruby/ext/grpc/rb_completion_queue.c

Index: third_party/grpc/src/ruby/ext/grpc/rb_completion_queue.c
diff --git a/third_party/grpc/src/ruby/ext/grpc/rb_completion_queue.c b/third_party/grpc/src/ruby/ext/grpc/rb_completion_queue.c
new file mode 100644
index 0000000000000000000000000000000000000000..1eb5a28750086a0017d012b9e302a1b359624c14
--- /dev/null
+++ b/third_party/grpc/src/ruby/ext/grpc/rb_completion_queue.c
@@ -0,0 +1,183 @@
+/*
+ *
+ * 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 <ruby/ruby.h>
+#include "rb_grpc_imports.generated.h"
+#include "rb_completion_queue.h"
+
+#include <ruby/ruby.h>
+#include <ruby/thread.h>
+
+#include <grpc/grpc.h>
+#include <grpc/support/time.h>
+#include "rb_grpc.h"
+
+/* grpc_rb_cCompletionQueue is the ruby class that proxies
+ * grpc_completion_queue. */
+static VALUE grpc_rb_cCompletionQueue = Qnil;
+
+/* Used to allow grpc_completion_queue_next call to release the GIL */
+typedef struct next_call_stack {
+  grpc_completion_queue *cq;
+  grpc_event event;
+  gpr_timespec timeout;
+  void *tag;
+} next_call_stack;
+
+/* Calls grpc_completion_queue_next without holding the ruby GIL */
+static void *grpc_rb_completion_queue_next_no_gil(void *param) {
+  next_call_stack *const next_call = (next_call_stack*)param;
+  next_call->event =
+      grpc_completion_queue_next(next_call->cq, next_call->timeout, NULL);
+  return NULL;
+}
+
+/* Calls grpc_completion_queue_pluck without holding the ruby GIL */
+static void *grpc_rb_completion_queue_pluck_no_gil(void *param) {
+  next_call_stack *const next_call = (next_call_stack*)param;
+  next_call->event = grpc_completion_queue_pluck(next_call->cq, next_call->tag,
+                                                 next_call->timeout, NULL);
+  return NULL;
+}
+
+/* Shuts down and drains the completion queue if necessary.
+ *
+ * This is done when the ruby completion queue object is about to be GCed.
+ */
+static void grpc_rb_completion_queue_shutdown_drain(grpc_completion_queue *cq) {
+  next_call_stack next_call;
+  grpc_completion_type type;
+  int drained = 0;
+  MEMZERO(&next_call, next_call_stack, 1);
+
+  grpc_completion_queue_shutdown(cq);
+  next_call.cq = cq;
+  next_call.event.type = GRPC_QUEUE_TIMEOUT;
+  /* TODO: the timeout should be a module level constant that defaults
+   * to gpr_inf_future(GPR_CLOCK_REALTIME).
+   *
+   * - at the moment this does not work, it stalls.  Using a small timeout like
+   *   this one works, and leads to fast test run times; a longer timeout was
+   *   causing unnecessary delays in the test runs.
+   *
+   * - investigate further, this is probably another example of C-level cleanup
+   * not working consistently in all cases.
+   */
+  next_call.timeout = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                                   gpr_time_from_micros(5e3, GPR_TIMESPAN));
+  do {
+    rb_thread_call_without_gvl(grpc_rb_completion_queue_next_no_gil,
+                               (void *)&next_call, NULL, NULL);
+    type = next_call.event.type;
+    if (type == GRPC_QUEUE_TIMEOUT) break;
+    if (type != GRPC_QUEUE_SHUTDOWN) {
+      ++drained;
+      rb_warning("completion queue shutdown: %d undrained events", drained);
+    }
+  } while (type != GRPC_QUEUE_SHUTDOWN);
+}
+
+/* Helper function to free a completion queue. */
+static void grpc_rb_completion_queue_destroy(void *p) {
+  grpc_completion_queue *cq = NULL;
+  if (p == NULL) {
+    return;
+  }
+  cq = (grpc_completion_queue *)p;
+  grpc_rb_completion_queue_shutdown_drain(cq);
+  grpc_completion_queue_destroy(cq);
+}
+
+static rb_data_type_t grpc_rb_completion_queue_data_type = {
+    "grpc_completion_queue",
+    {GRPC_RB_GC_NOT_MARKED, grpc_rb_completion_queue_destroy,
+     GRPC_RB_MEMSIZE_UNAVAILABLE, {NULL, NULL}},
+    NULL, NULL,
+#ifdef RUBY_TYPED_FREE_IMMEDIATELY
+    /* cannot immediately free because grpc_rb_completion_queue_shutdown_drain
+     * calls rb_thread_call_without_gvl. */
+    0,
+#endif
+};
+
+/* Allocates a completion queue. */
+static VALUE grpc_rb_completion_queue_alloc(VALUE cls) {
+  grpc_completion_queue *cq = grpc_completion_queue_create(NULL);
+  if (cq == NULL) {
+    rb_raise(rb_eArgError, "could not create a completion queue: not sure why");
+  }
+  return TypedData_Wrap_Struct(cls, &grpc_rb_completion_queue_data_type, cq);
+}
+
+/* Blocks until the next event for given tag is available, and returns the
+ * event. */
+grpc_event grpc_rb_completion_queue_pluck_event(VALUE self, VALUE tag,
+                                                VALUE timeout) {
+  next_call_stack next_call;
+  MEMZERO(&next_call, next_call_stack, 1);
+  TypedData_Get_Struct(self, grpc_completion_queue,
+                       &grpc_rb_completion_queue_data_type, next_call.cq);
+  if (TYPE(timeout) == T_NIL) {
+    next_call.timeout = gpr_inf_future(GPR_CLOCK_REALTIME);
+  } else {
+    next_call.timeout = grpc_rb_time_timeval(timeout, /* absolute time*/ 0);
+  }
+  if (TYPE(tag) == T_NIL) {
+    next_call.tag = NULL;
+  } else {
+    next_call.tag = ROBJECT(tag);
+  }
+  next_call.event.type = GRPC_QUEUE_TIMEOUT;
+  rb_thread_call_without_gvl(grpc_rb_completion_queue_pluck_no_gil,
+                             (void *)&next_call, NULL, NULL);
+  return next_call.event;
+}
+
+void Init_grpc_completion_queue() {
+  grpc_rb_cCompletionQueue =
+      rb_define_class_under(grpc_rb_mGrpcCore, "CompletionQueue", rb_cObject);
+
+  /* constructor: uses an alloc func without an initializer. Using a simple
+     alloc func works here as the grpc header does not specify any args for
+     this func, so no separate initialization step is necessary. */
+  rb_define_alloc_func(grpc_rb_cCompletionQueue,
+                       grpc_rb_completion_queue_alloc);
+}
+
+/* Gets the wrapped completion queue from the ruby wrapper */
+grpc_completion_queue *grpc_rb_get_wrapped_completion_queue(VALUE v) {
+  grpc_completion_queue *cq = NULL;
+  TypedData_Get_Struct(v, grpc_completion_queue,
+                       &grpc_rb_completion_queue_data_type, cq);
+  return cq;
+}