Move headers from grpc++ to grpcpp

1 files changed, 383 insertions, 0 deletions

diff --git a/include/grpcpp/impl/codegen/completion_queue.h b/include/grpcpp/impl/codegen/completion_queue.h
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+++ b/include/grpcpp/impl/codegen/completion_queue.h
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+/*
+ *
+ * Copyright 2015-2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+/// A completion queue implements a concurrent producer-consumer queue, with
+/// two main API-exposed methods: \a Next and \a AsyncNext. These
+/// methods are the essential component of the gRPC C++ asynchronous API.
+/// There is also a \a Shutdown method to indicate that a given completion queue
+/// will no longer have regular events. This must be called before the
+/// completion queue is destroyed.
+/// All completion queue APIs are thread-safe and may be used concurrently with
+/// any other completion queue API invocation; it is acceptable to have
+/// multiple threads calling \a Next or \a AsyncNext on the same or different
+/// completion queues, or to call these methods concurrently with a \a Shutdown
+/// elsewhere.
+/// \remark{All other API calls on completion queue should be completed before
+/// a completion queue destructor is called.}
+#ifndef GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_H
+#define GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_H
+
+#include <grpc/impl/codegen/atm.h>
+#include <grpcpp/impl/codegen/completion_queue_tag.h>
+#include <grpcpp/impl/codegen/core_codegen_interface.h>
+#include <grpcpp/impl/codegen/grpc_library.h>
+#include <grpcpp/impl/codegen/status.h>
+#include <grpcpp/impl/codegen/time.h>
+
+struct grpc_completion_queue;
+
+namespace grpc {
+
+template <class R>
+class ClientReader;
+template <class W>
+class ClientWriter;
+template <class W, class R>
+class ClientReaderWriter;
+template <class R>
+class ServerReader;
+template <class W>
+class ServerWriter;
+namespace internal {
+template <class W, class R>
+class ServerReaderWriterBody;
+}  // namespace internal
+
+class Channel;
+class ChannelInterface;
+class ClientContext;
+class CompletionQueue;
+class Server;
+class ServerBuilder;
+class ServerContext;
+class ServerInterface;
+
+namespace internal {
+class CompletionQueueTag;
+class RpcMethod;
+template <class ServiceType, class RequestType, class ResponseType>
+class RpcMethodHandler;
+template <class ServiceType, class RequestType, class ResponseType>
+class ClientStreamingHandler;
+template <class ServiceType, class RequestType, class ResponseType>
+class ServerStreamingHandler;
+template <class ServiceType, class RequestType, class ResponseType>
+class BidiStreamingHandler;
+class UnknownMethodHandler;
+template <class Streamer, bool WriteNeeded>
+class TemplatedBidiStreamingHandler;
+template <class InputMessage, class OutputMessage>
+class BlockingUnaryCallImpl;
+}  // namespace internal
+
+extern CoreCodegenInterface* g_core_codegen_interface;
+
+/// A thin wrapper around \ref grpc_completion_queue (see \ref
+/// src/core/lib/surface/completion_queue.h).
+/// See \ref doc/cpp/perf_notes.md for notes on best practices for high
+/// performance servers.
+class CompletionQueue : private GrpcLibraryCodegen {
+ public:
+  /// Default constructor. Implicitly creates a \a grpc_completion_queue
+  /// instance.
+  CompletionQueue()
+      : CompletionQueue(grpc_completion_queue_attributes{
+            GRPC_CQ_CURRENT_VERSION, GRPC_CQ_NEXT, GRPC_CQ_DEFAULT_POLLING}) {}
+
+  /// Wrap \a take, taking ownership of the instance.
+  ///
+  /// \param take The completion queue instance to wrap. Ownership is taken.
+  explicit CompletionQueue(grpc_completion_queue* take);
+
+  /// Destructor. Destroys the owned wrapped completion queue / instance.
+  ~CompletionQueue() {
+    g_core_codegen_interface->grpc_completion_queue_destroy(cq_);
+  }
+
+  /// Tri-state return for AsyncNext: SHUTDOWN, GOT_EVENT, TIMEOUT.
+  enum NextStatus {
+    SHUTDOWN,   ///< The completion queue has been shutdown and fully-drained
+    GOT_EVENT,  ///< Got a new event; \a tag will be filled in with its
+                ///< associated value; \a ok indicating its success.
+    TIMEOUT     ///< deadline was reached.
+  };
+
+  /// Read from the queue, blocking until an event is available or the queue is
+  /// shutting down.
+  ///
+  /// \param tag[out] Updated to point to the read event's tag.
+  /// \param ok[out] true if read a successful event, false otherwise.
+  ///
+  /// Note that each tag sent to the completion queue (through RPC operations
+  /// or alarms) will be delivered out of the completion queue by a call to
+  /// Next (or a related method), regardless of whether the operation succeeded
+  /// or not. Success here means that this operation completed in the normal
+  /// valid manner.
+  ///
+  /// Server-side RPC request: \a ok indicates that the RPC has indeed
+  /// been started. If it is false, the server has been Shutdown
+  /// before this particular call got matched to an incoming RPC.
+  ///
+  /// Client-side StartCall/RPC invocation: \a ok indicates that the RPC is
+  /// going to go to the wire. If it is false, it not going to the wire. This
+  /// would happen if the channel is either permanently broken or
+  /// transiently broken but with the fail-fast option. (Note that async unary
+  /// RPCs don't post a CQ tag at this point, nor do client-streaming
+  /// or bidi-streaming RPCs that have the initial metadata corked option set.)
+  ///
+  /// Client-side Write, Client-side WritesDone, Server-side Write,
+  /// Server-side Finish, Server-side SendInitialMetadata (which is
+  /// typically included in Write or Finish when not done explicitly):
+  /// \a ok means that the data/metadata/status/etc is going to go to the
+  /// wire. If it is false, it not going to the wire because the call
+  /// is already dead (i.e., canceled, deadline expired, other side
+  /// dropped the channel, etc).
+  ///
+  /// Client-side Read, Server-side Read, Client-side
+  /// RecvInitialMetadata (which is typically included in Read if not
+  /// done explicitly): \a ok indicates whether there is a valid message
+  /// that got read. If not, you know that there are certainly no more
+  /// messages that can ever be read from this stream. For the client-side
+  /// operations, this only happens because the call is dead. For the
+  /// server-sider operation, though, this could happen because the client
+  /// has done a WritesDone already.
+  ///
+  /// Client-side Finish: \a ok should always be true
+  ///
+  /// Server-side AsyncNotifyWhenDone: \a ok should always be true
+  ///
+  /// Alarm: \a ok is true if it expired, false if it was canceled
+  ///
+  /// \return true if got an event, false if the queue is fully drained and
+  ///         shut down.
+  bool Next(void** tag, bool* ok) {
+    return (AsyncNextInternal(tag, ok,
+                              g_core_codegen_interface->gpr_inf_future(
+                                  GPR_CLOCK_REALTIME)) != SHUTDOWN);
+  }
+
+  /// Read from the queue, blocking up to \a deadline (or the queue's shutdown).
+  /// Both \a tag and \a ok are updated upon success (if an event is available
+  /// within the \a deadline).  A \a tag points to an arbitrary location usually
+  /// employed to uniquely identify an event.
+  ///
+  /// \param tag[out] Upon sucess, updated to point to the event's tag.
+  /// \param ok[out] Upon sucess, true if a successful event, false otherwise
+  ///        See documentation for CompletionQueue::Next for explanation of ok
+  /// \param deadline[in] How long to block in wait for an event.
+  ///
+  /// \return The type of event read.
+  template <typename T>
+  NextStatus AsyncNext(void** tag, bool* ok, const T& deadline) {
+    TimePoint<T> deadline_tp(deadline);
+    return AsyncNextInternal(tag, ok, deadline_tp.raw_time());
+  }
+
+  /// EXPERIMENTAL
+  /// First executes \a F, then reads from the queue, blocking up to
+  /// \a deadline (or the queue's shutdown).
+  /// Both \a tag and \a ok are updated upon success (if an event is available
+  /// within the \a deadline).  A \a tag points to an arbitrary location usually
+  /// employed to uniquely identify an event.
+  ///
+  /// \param F[in] Function to execute before calling AsyncNext on this queue.
+  /// \param tag[out] Upon sucess, updated to point to the event's tag.
+  /// \param ok[out] Upon sucess, true if read a regular event, false otherwise.
+  /// \param deadline[in] How long to block in wait for an event.
+  ///
+  /// \return The type of event read.
+  template <typename T, typename F>
+  NextStatus DoThenAsyncNext(F&& f, void** tag, bool* ok, const T& deadline) {
+    CompletionQueueTLSCache cache = CompletionQueueTLSCache(this);
+    f();
+    if (cache.Flush(tag, ok)) {
+      return GOT_EVENT;
+    } else {
+      return AsyncNext(tag, ok, deadline);
+    }
+  }
+
+  /// Request the shutdown of the queue.
+  ///
+  /// \warning This method must be called at some point if this completion queue
+  /// is accessed with Next or AsyncNext. \a Next will not return false
+  /// until this method has been called and all pending tags have been drained.
+  /// (Likewise for \a AsyncNext returning \a NextStatus::SHUTDOWN .)
+  /// Only once either one of these methods does that (that is, once the queue
+  /// has been \em drained) can an instance of this class be destroyed.
+  /// Also note that applications must ensure that no work is enqueued on this
+  /// completion queue after this method is called.
+  void Shutdown();
+
+  /// Returns a \em raw pointer to the underlying \a grpc_completion_queue
+  /// instance.
+  ///
+  /// \warning Remember that the returned instance is owned. No transfer of
+  /// owership is performed.
+  grpc_completion_queue* cq() { return cq_; }
+
+ protected:
+  /// Private constructor of CompletionQueue only visible to friend classes
+  CompletionQueue(const grpc_completion_queue_attributes& attributes) {
+    cq_ = g_core_codegen_interface->grpc_completion_queue_create(
+        g_core_codegen_interface->grpc_completion_queue_factory_lookup(
+            &attributes),
+        &attributes, NULL);
+    InitialAvalanching();  // reserve this for the future shutdown
+  }
+
+ private:
+  // Friend synchronous wrappers so that they can access Pluck(), which is
+  // a semi-private API geared towards the synchronous implementation.
+  template <class R>
+  friend class ::grpc::ClientReader;
+  template <class W>
+  friend class ::grpc::ClientWriter;
+  template <class W, class R>
+  friend class ::grpc::ClientReaderWriter;
+  template <class R>
+  friend class ::grpc::ServerReader;
+  template <class W>
+  friend class ::grpc::ServerWriter;
+  template <class W, class R>
+  friend class ::grpc::internal::ServerReaderWriterBody;
+  template <class ServiceType, class RequestType, class ResponseType>
+  friend class ::grpc::internal::RpcMethodHandler;
+  template <class ServiceType, class RequestType, class ResponseType>
+  friend class ::grpc::internal::ClientStreamingHandler;
+  template <class ServiceType, class RequestType, class ResponseType>
+  friend class ::grpc::internal::ServerStreamingHandler;
+  template <class Streamer, bool WriteNeeded>
+  friend class ::grpc::internal::TemplatedBidiStreamingHandler;
+  friend class ::grpc::internal::UnknownMethodHandler;
+  friend class ::grpc::Server;
+  friend class ::grpc::ServerContext;
+  friend class ::grpc::ServerInterface;
+  template <class InputMessage, class OutputMessage>
+  friend class ::grpc::internal::BlockingUnaryCallImpl;
+
+  /// EXPERIMENTAL
+  /// Creates a Thread Local cache to store the first event
+  /// On this completion queue queued from this thread.  Once
+  /// initialized, it must be flushed on the same thread.
+  class CompletionQueueTLSCache {
+   public:
+    CompletionQueueTLSCache(CompletionQueue* cq);
+    ~CompletionQueueTLSCache();
+    bool Flush(void** tag, bool* ok);
+
+   private:
+    CompletionQueue* cq_;
+    bool flushed_;
+  };
+
+  NextStatus AsyncNextInternal(void** tag, bool* ok, gpr_timespec deadline);
+
+  /// Wraps \a grpc_completion_queue_pluck.
+  /// \warning Must not be mixed with calls to \a Next.
+  bool Pluck(internal::CompletionQueueTag* tag) {
+    auto deadline =
+        g_core_codegen_interface->gpr_inf_future(GPR_CLOCK_REALTIME);
+    auto ev = g_core_codegen_interface->grpc_completion_queue_pluck(
+        cq_, tag, deadline, nullptr);
+    bool ok = ev.success != 0;
+    void* ignored = tag;
+    GPR_CODEGEN_ASSERT(tag->FinalizeResult(&ignored, &ok));
+    GPR_CODEGEN_ASSERT(ignored == tag);
+    // Ignore mutations by FinalizeResult: Pluck returns the C API status
+    return ev.success != 0;
+  }
+
+  /// Performs a single polling pluck on \a tag.
+  /// \warning Must not be mixed with calls to \a Next.
+  ///
+  /// TODO: sreek - This calls tag->FinalizeResult() even if the cq_ is already
+  /// shutdown. This is most likely a bug and if it is a bug, then change this
+  /// implementation to simple call the other TryPluck function with a zero
+  /// timeout. i.e:
+  ///      TryPluck(tag, gpr_time_0(GPR_CLOCK_REALTIME))
+  void TryPluck(internal::CompletionQueueTag* tag) {
+    auto deadline = g_core_codegen_interface->gpr_time_0(GPR_CLOCK_REALTIME);
+    auto ev = g_core_codegen_interface->grpc_completion_queue_pluck(
+        cq_, tag, deadline, nullptr);
+    if (ev.type == GRPC_QUEUE_TIMEOUT) return;
+    bool ok = ev.success != 0;
+    void* ignored = tag;
+    // the tag must be swallowed if using TryPluck
+    GPR_CODEGEN_ASSERT(!tag->FinalizeResult(&ignored, &ok));
+  }
+
+  /// Performs a single polling pluck on \a tag. Calls tag->FinalizeResult if
+  /// the pluck() was successful and returned the tag.
+  ///
+  /// This exects tag->FinalizeResult (if called) to return 'false' i.e expects
+  /// that the tag is internal not something that is returned to the user.
+  void TryPluck(internal::CompletionQueueTag* tag, gpr_timespec deadline) {
+    auto ev = g_core_codegen_interface->grpc_completion_queue_pluck(
+        cq_, tag, deadline, nullptr);
+    if (ev.type == GRPC_QUEUE_TIMEOUT || ev.type == GRPC_QUEUE_SHUTDOWN) {
+      return;
+    }
+
+    bool ok = ev.success != 0;
+    void* ignored = tag;
+    GPR_CODEGEN_ASSERT(!tag->FinalizeResult(&ignored, &ok));
+  }
+
+  /// Manage state of avalanching operations : completion queue tags that
+  /// trigger other completion queue operations. The underlying core completion
+  /// queue should not really shutdown until all avalanching operations have
+  /// been finalized. Note that we maintain the requirement that an avalanche
+  /// registration must take place before CQ shutdown (which must be maintained
+  /// elsehwere)
+  void InitialAvalanching() {
+    gpr_atm_rel_store(&avalanches_in_flight_, static_cast<gpr_atm>(1));
+  }
+  void RegisterAvalanching() {
+    gpr_atm_no_barrier_fetch_add(&avalanches_in_flight_,
+                                 static_cast<gpr_atm>(1));
+  }
+  void CompleteAvalanching();
+
+  grpc_completion_queue* cq_;  // owned
+
+  gpr_atm avalanches_in_flight_;
+};
+
+/// A specific type of completion queue used by the processing of notifications
+/// by servers. Instantiated by \a ServerBuilder.
+class ServerCompletionQueue : public CompletionQueue {
+ public:
+  bool IsFrequentlyPolled() { return polling_type_ != GRPC_CQ_NON_LISTENING; }
+
+ private:
+  grpc_cq_polling_type polling_type_;
+  friend class ServerBuilder;
+  /// \param is_frequently_polled Informs the GRPC library about whether the
+  /// server completion queue would be actively polled (by calling Next() or
+  /// AsyncNext()). By default all server completion queues are assumed to be
+  /// frequently polled.
+  ServerCompletionQueue(grpc_cq_polling_type polling_type)
+      : CompletionQueue(grpc_completion_queue_attributes{
+            GRPC_CQ_CURRENT_VERSION, GRPC_CQ_NEXT, polling_type}),
+        polling_type_(polling_type) {}
+};
+
+}  // namespace grpc
+
+#endif  // GRPCPP_IMPL_CODEGEN_COMPLETION_QUEUE_H