|
|
@@ -0,0 +1,211 @@
|
|
|
+/*
|
|
|
+ *
|
|
|
+ * Copyright 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.
|
|
|
+ *
|
|
|
+ */
|
|
|
+
|
|
|
+#ifndef GRPCXX_CHANNEL_FILTER_H
|
|
|
+#define GRPCXX_CHANNEL_FILTER_H
|
|
|
+
|
|
|
+#include <grpc/grpc.h>
|
|
|
+
|
|
|
+#include <vector>
|
|
|
+
|
|
|
+#include "src/core/lib/channel/channel_stack.h"
|
|
|
+#include "src/core/lib/surface/channel_init.h"
|
|
|
+
|
|
|
+//
|
|
|
+// An interface to define filters.
|
|
|
+//
|
|
|
+// To define a filter, implement a subclass of each of CallData and
|
|
|
+// ChannelData. Then register the filter like this:
|
|
|
+// RegisterChannelFilter<MyChannelDataSubclass, MyCallDataSubclass>(
|
|
|
+// "name-of-filter", GRPC_SERVER_CHANNEL, INT_MAX);
|
|
|
+//
|
|
|
+
|
|
|
+namespace grpc {
|
|
|
+
|
|
|
+// Represents call data.
|
|
|
+// Note: Must be copyable.
|
|
|
+class CallData {
|
|
|
+ public:
|
|
|
+ // Do not override the destructor. Instead, put clean-up code in the
|
|
|
+ // Destroy() method.
|
|
|
+ virtual ~CallData() {}
|
|
|
+
|
|
|
+ virtual void Destroy() {}
|
|
|
+
|
|
|
+ virtual void StartTransportStreamOp(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ grpc_transport_stream_op *op);
|
|
|
+
|
|
|
+ virtual void SetPollsetOrPollsetSet(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ grpc_polling_entity *pollent);
|
|
|
+
|
|
|
+ virtual char* GetPeer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem);
|
|
|
+
|
|
|
+ protected:
|
|
|
+ CallData() {}
|
|
|
+};
|
|
|
+
|
|
|
+// Represents channel data.
|
|
|
+// Note: Must be copyable.
|
|
|
+class ChannelData {
|
|
|
+ public:
|
|
|
+ // Do not override the destructor. Instead, put clean-up code in the
|
|
|
+ // Destroy() method.
|
|
|
+ virtual ~ChannelData() {}
|
|
|
+
|
|
|
+ virtual void Destroy() {}
|
|
|
+
|
|
|
+ virtual void StartTransportOp(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
|
|
|
+ grpc_transport_op *op);
|
|
|
+
|
|
|
+ protected:
|
|
|
+ ChannelData() {}
|
|
|
+};
|
|
|
+
|
|
|
+namespace internal {
|
|
|
+
|
|
|
+// Defines static members for passing to C core.
|
|
|
+template<typename ChannelDataType, typename CallDataType>
|
|
|
+class ChannelFilter {
|
|
|
+ static const size_t call_data_size = sizeof(CallDataType);
|
|
|
+
|
|
|
+ static void InitCallElement(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ grpc_call_element_args *args) {
|
|
|
+ CallDataType* call_data = elem->call_data;
|
|
|
+ *call_data = CallDataType();
|
|
|
+ }
|
|
|
+
|
|
|
+ static void DestroyCallElement(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ const grpc_call_stats *stats, void *and_free_memory) {
|
|
|
+ CallDataType* call_data = elem->call_data;
|
|
|
+ // Can't destroy the object here, since it's not allocated by
|
|
|
+ // itself; instead, it's part of a larger allocation managed by
|
|
|
+ // C-core. So instead, we call the Destroy() method.
|
|
|
+ call_data->Destroy();
|
|
|
+ }
|
|
|
+
|
|
|
+ static void StartTransportStreamOp(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ grpc_transport_stream_op *op) {
|
|
|
+ CallDataType* call_data = elem->call_data;
|
|
|
+ call_data->StartTransportStreamOp(exec_ctx, op);
|
|
|
+ }
|
|
|
+
|
|
|
+ static void SetPollsetOrPollsetSet(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
|
|
|
+ grpc_polling_entity *pollent) {
|
|
|
+ CallDataType* call_data = elem->call_data;
|
|
|
+ call_data->SetPollsetOrPollsetSet(exec_ctx, pollent);
|
|
|
+ }
|
|
|
+
|
|
|
+ static char* GetPeer(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
|
|
|
+ CallDataType* call_data = elem->call_data;
|
|
|
+ return call_data->GetPeer(exec_ctx);
|
|
|
+ }
|
|
|
+
|
|
|
+ static const size_t channel_data_size = sizeof(ChannelDataType);
|
|
|
+
|
|
|
+ static void InitChannelElement(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
|
|
|
+ grpc_channel_element_args *args) {
|
|
|
+ ChannelDataType* channel_data = elem->channel_data;
|
|
|
+ *channel_data = ChannelDataType();
|
|
|
+ }
|
|
|
+
|
|
|
+ static void DestroyChannelElement(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_channel_element *elem) {
|
|
|
+ ChannelDataType* channel_data = elem->channel_data;
|
|
|
+ // Can't destroy the object here, since it's not allocated by
|
|
|
+ // itself; instead, it's part of a larger allocation managed by
|
|
|
+ // C-core. So instead, we call the Destroy() method.
|
|
|
+ channel_data->Destroy();
|
|
|
+ }
|
|
|
+
|
|
|
+ static void StartTransportOp(
|
|
|
+ grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
|
|
|
+ grpc_transport_op *op) {
|
|
|
+ ChannelDataType* channel_data = elem->channel_data;
|
|
|
+ channel_data->StartTransportOp(exec_ctx, op);
|
|
|
+ }
|
|
|
+};
|
|
|
+
|
|
|
+struct FilterRecord {
|
|
|
+ grpc_channel_stack_type stack_type;
|
|
|
+ int priority;
|
|
|
+ grpc_channel_filter filter;
|
|
|
+};
|
|
|
+extern std::vector<FilterRecord>* channel_filters;
|
|
|
+
|
|
|
+void ChannelFilterPluginInit();
|
|
|
+void ChannelFilterPluginShutdown() {}
|
|
|
+
|
|
|
+} // namespace internal
|
|
|
+
|
|
|
+// Registers a new filter.
|
|
|
+// Must be called by only one thread at a time.
|
|
|
+template<typename ChannelDataType, typename CallDataType>
|
|
|
+void RegisterChannelFilter(const char* name,
|
|
|
+ grpc_channel_stack_type stack_type, int priority) {
|
|
|
+ // If we haven't been called before, initialize channel_filters and
|
|
|
+ // call grpc_register_plugin().
|
|
|
+ if (internal::channel_filters == nullptr) {
|
|
|
+ grpc_register_plugin(internal::ChannelFilterPluginInit,
|
|
|
+ internal::ChannelFilterPluginShutdown);
|
|
|
+ internal::channel_filters = new std::vector<internal::FilterRecord>();
|
|
|
+ }
|
|
|
+ // Add an entry to channel_filters. The filter will be added when the
|
|
|
+ // C-core initialization code calls ChannelFilterPluginInit().
|
|
|
+ typedef internal::ChannelFilter<ChannelDataType, CallDataType> FilterType;
|
|
|
+ internal::channel_filters->emplace_back({
|
|
|
+ stack_type, priority, {
|
|
|
+ FilterType::StartTransportStreamOp,
|
|
|
+ FilterType::StartTransportOp,
|
|
|
+ FilterType::call_data_size,
|
|
|
+ FilterType::InitCallElement,
|
|
|
+ FilterType::SetPollsetOrPollsetSet,
|
|
|
+ FilterType::DestroyCallElement,
|
|
|
+ FilterType::channel_data_size,
|
|
|
+ FilterType::InitChannelElement,
|
|
|
+ FilterType::DestroyChannelElement,
|
|
|
+ FilterType::GetPeer,
|
|
|
+ name}});
|
|
|
+}
|
|
|
+
|
|
|
+} // namespace grpc
|
|
|
+
|
|
|
+#endif // GRPCXX_CHANNEL_FILTER_H
|
Mark D. Roth