Merge pull request #13357 from markdroth/reference_counted

Add ReferenceCounted base class.

17 files changed, 874 insertions, 0 deletions

diff --git a/BUILD b/BUILD
index df334cd322..d904a1ec6e 100644
--- a/BUILD
+++ b/BUILD
@@ -539,6 +539,28 @@ grpc_cc_library(
 )
 
 grpc_cc_library(
+    name = "debug_location",
+    public_hdrs = ["src/core/lib/support/debug_location.h"],
+    language = "c++",
+)
+
+grpc_cc_library(
+    name = "ref_counted",
+    public_hdrs = ["src/core/lib/support/ref_counted.h"],
+    language = "c++",
+    deps = [
+        "grpc_trace",
+        "debug_location",
+    ],
+)
+
+grpc_cc_library(
+    name = "ref_counted_ptr",
+    public_hdrs = ["src/core/lib/support/ref_counted_ptr.h"],
+    language = "c++",
+)
+
+grpc_cc_library(
     name = "grpc_base_c",
     srcs = [
         "src/core/lib/backoff/backoff.cc",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3778953001..760e4fa585 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -738,6 +738,8 @@ endif()
 add_dependencies(buildtests_cxx qps_worker)
 add_dependencies(buildtests_cxx reconnect_interop_client)
 add_dependencies(buildtests_cxx reconnect_interop_server)
+add_dependencies(buildtests_cxx ref_counted_ptr_test)
+add_dependencies(buildtests_cxx ref_counted_test)
 add_dependencies(buildtests_cxx secure_auth_context_test)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx secure_sync_unary_ping_pong_test)
@@ -12018,6 +12020,84 @@ target_link_libraries(reconnect_interop_server
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
+add_executable(ref_counted_ptr_test
+  test/core/support/ref_counted_ptr_test.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(ref_counted_ptr_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(ref_counted_ptr_test
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc++
+  grpc
+  gpr_test_util
+  gpr
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
+add_executable(ref_counted_test
+  test/core/support/ref_counted_test.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(ref_counted_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(ref_counted_test
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc++
+  grpc
+  gpr_test_util
+  gpr
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
 add_executable(secure_auth_context_test
   test/cpp/common/secure_auth_context_test.cc
   third_party/googletest/googletest/src/gtest-all.cc
diff --git a/Makefile b/Makefile
index f985a1e238..3ce3005924 100644
--- a/Makefile
+++ b/Makefile
@@ -1164,6 +1164,8 @@ qps_openloop_test: $(BINDIR)/$(CONFIG)/qps_openloop_test
 qps_worker: $(BINDIR)/$(CONFIG)/qps_worker
 reconnect_interop_client: $(BINDIR)/$(CONFIG)/reconnect_interop_client
 reconnect_interop_server: $(BINDIR)/$(CONFIG)/reconnect_interop_server
+ref_counted_ptr_test: $(BINDIR)/$(CONFIG)/ref_counted_ptr_test
+ref_counted_test: $(BINDIR)/$(CONFIG)/ref_counted_test
 secure_auth_context_test: $(BINDIR)/$(CONFIG)/secure_auth_context_test
 secure_sync_unary_ping_pong_test: $(BINDIR)/$(CONFIG)/secure_sync_unary_ping_pong_test
 server_builder_plugin_test: $(BINDIR)/$(CONFIG)/server_builder_plugin_test
@@ -1598,6 +1600,8 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/qps_worker \
   $(BINDIR)/$(CONFIG)/reconnect_interop_client \
   $(BINDIR)/$(CONFIG)/reconnect_interop_server \
+  $(BINDIR)/$(CONFIG)/ref_counted_ptr_test \
+  $(BINDIR)/$(CONFIG)/ref_counted_test \
   $(BINDIR)/$(CONFIG)/secure_auth_context_test \
   $(BINDIR)/$(CONFIG)/secure_sync_unary_ping_pong_test \
   $(BINDIR)/$(CONFIG)/server_builder_plugin_test \
@@ -1723,6 +1727,8 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/qps_worker \
   $(BINDIR)/$(CONFIG)/reconnect_interop_client \
   $(BINDIR)/$(CONFIG)/reconnect_interop_server \
+  $(BINDIR)/$(CONFIG)/ref_counted_ptr_test \
+  $(BINDIR)/$(CONFIG)/ref_counted_test \
   $(BINDIR)/$(CONFIG)/secure_auth_context_test \
   $(BINDIR)/$(CONFIG)/secure_sync_unary_ping_pong_test \
   $(BINDIR)/$(CONFIG)/server_builder_plugin_test \
@@ -2123,6 +2129,10 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/proto_utils_test || ( echo test proto_utils_test failed ; exit 1 )
 	$(E) "[RUN]     Testing qps_openloop_test"
 	$(Q) $(BINDIR)/$(CONFIG)/qps_openloop_test || ( echo test qps_openloop_test failed ; exit 1 )
+	$(E) "[RUN]     Testing ref_counted_ptr_test"
+	$(Q) $(BINDIR)/$(CONFIG)/ref_counted_ptr_test || ( echo test ref_counted_ptr_test failed ; exit 1 )
+	$(E) "[RUN]     Testing ref_counted_test"
+	$(Q) $(BINDIR)/$(CONFIG)/ref_counted_test || ( echo test ref_counted_test failed ; exit 1 )
 	$(E) "[RUN]     Testing secure_auth_context_test"
 	$(Q) $(BINDIR)/$(CONFIG)/secure_auth_context_test || ( echo test secure_auth_context_test failed ; exit 1 )
 	$(E) "[RUN]     Testing secure_sync_unary_ping_pong_test"
@@ -16482,6 +16492,92 @@ endif
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/reconnect_interop_server.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 
 
+REF_COUNTED_PTR_TEST_SRC = \
+    test/core/support/ref_counted_ptr_test.cc \
+
+REF_COUNTED_PTR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(REF_COUNTED_PTR_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/ref_counted_ptr_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/ref_counted_ptr_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/ref_counted_ptr_test: $(PROTOBUF_DEP) $(REF_COUNTED_PTR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(REF_COUNTED_PTR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/ref_counted_ptr_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/ref_counted_ptr_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_ref_counted_ptr_test: $(REF_COUNTED_PTR_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(REF_COUNTED_PTR_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
+REF_COUNTED_TEST_SRC = \
+    test/core/support/ref_counted_test.cc \
+
+REF_COUNTED_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(REF_COUNTED_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/ref_counted_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/ref_counted_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/ref_counted_test: $(PROTOBUF_DEP) $(REF_COUNTED_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(REF_COUNTED_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/ref_counted_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/ref_counted_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_ref_counted_test: $(REF_COUNTED_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(REF_COUNTED_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 SECURE_AUTH_CONTEXT_TEST_SRC = \
     test/cpp/common/secure_auth_context_test.cc \
 
diff --git a/build.yaml b/build.yaml
index df92b6e347..0908f7efd2 100644
--- a/build.yaml
+++ b/build.yaml
@@ -398,6 +398,9 @@ filegroups:
   - src/core/lib/slice/slice_hash_table.h
   - src/core/lib/slice/slice_internal.h
   - src/core/lib/slice/slice_string_helpers.h
+  - src/core/lib/support/debug_location.h
+  - src/core/lib/support/ref_counted.h
+  - src/core/lib/support/ref_counted_ptr.h
   - src/core/lib/surface/alarm_internal.h
   - src/core/lib/surface/api_trace.h
   - src/core/lib/surface/call.h
@@ -4535,6 +4538,34 @@ targets:
   - gpr_test_util
   - gpr
   - grpc++_test_config
+- name: ref_counted_ptr_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/core/support/ref_counted_ptr_test.cc
+  deps:
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  uses:
+  - grpc++_test
+- name: ref_counted_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/core/support/ref_counted_test.cc
+  deps:
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  uses:
+  - grpc++_test
 - name: secure_auth_context_test
   gtest: true
   build: test
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index c7dd5a865c..82dda2017f 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -418,6 +418,9 @@ Pod::Spec.new do |s|
                       'src/core/lib/slice/slice_hash_table.h',
                       'src/core/lib/slice/slice_internal.h',
                       'src/core/lib/slice/slice_string_helpers.h',
+                      'src/core/lib/support/debug_location.h',
+                      'src/core/lib/support/ref_counted.h',
+                      'src/core/lib/support/ref_counted_ptr.h',
                       'src/core/lib/surface/alarm_internal.h',
                       'src/core/lib/surface/api_trace.h',
                       'src/core/lib/surface/call.h',
@@ -895,6 +898,9 @@ Pod::Spec.new do |s|
                               'src/core/lib/slice/slice_hash_table.h',
                               'src/core/lib/slice/slice_internal.h',
                               'src/core/lib/slice/slice_string_helpers.h',
+                              'src/core/lib/support/debug_location.h',
+                              'src/core/lib/support/ref_counted.h',
+                              'src/core/lib/support/ref_counted_ptr.h',
                               'src/core/lib/surface/alarm_internal.h',
                               'src/core/lib/surface/api_trace.h',
                               'src/core/lib/surface/call.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index 7a850a5ac2..e553b770e4 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -348,6 +348,9 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/slice/slice_hash_table.h )
   s.files += %w( src/core/lib/slice/slice_internal.h )
   s.files += %w( src/core/lib/slice/slice_string_helpers.h )
+  s.files += %w( src/core/lib/support/debug_location.h )
+  s.files += %w( src/core/lib/support/ref_counted.h )
+  s.files += %w( src/core/lib/support/ref_counted_ptr.h )
   s.files += %w( src/core/lib/surface/alarm_internal.h )
   s.files += %w( src/core/lib/surface/api_trace.h )
   s.files += %w( src/core/lib/surface/call.h )
diff --git a/package.xml b/package.xml
index 2b6c149a6b..435fb4c2c2 100644
--- a/package.xml
+++ b/package.xml
@@ -360,6 +360,9 @@
     <file baseinstalldir="/" name="src/core/lib/slice/slice_hash_table.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_string_helpers.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/debug_location.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/ref_counted.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/ref_counted_ptr.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/alarm_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/api_trace.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/call.h" role="src" />
diff --git a/src/core/lib/support/debug_location.h b/src/core/lib/support/debug_location.h
new file mode 100644
index 0000000000..0939da595d
--- /dev/null
+++ b/src/core/lib/support/debug_location.h
@@ -0,0 +1,52 @@
+/*
+ *
+ * Copyright 2017 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_DEBUG_LOCATION_H
+#define GRPC_CORE_LIB_SUPPORT_DEBUG_LOCATION_H
+
+namespace grpc_core {
+
+// Used for tracking file and line where a call is made for debug builds.
+// No-op for non-debug builds.
+// Callers can use the DEBUG_LOCATION macro in either case.
+#ifndef NDEBUG
+class DebugLocation {
+ public:
+  DebugLocation(const char* file, int line) : file_(file), line_(line) {}
+  bool Log() const { return true; }
+  const char* file() const { return file_; }
+  int line() const { return line_; }
+
+ private:
+  const char* file_;
+  const int line_;
+};
+#define DEBUG_LOCATION DebugLocation(__FILE__, __LINE__)
+#else
+class DebugLocation {
+ public:
+  bool Log() const { return false; }
+  const char* file() const { return nullptr; }
+  int line() const { return -1; }
+};
+#define DEBUG_LOCATION DebugLocation()
+#endif
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_LIB_SUPPORT_DEBUG_LOCATION_H */
diff --git a/src/core/lib/support/ref_counted.h b/src/core/lib/support/ref_counted.h
new file mode 100644
index 0000000000..4c662f9119
--- /dev/null
+++ b/src/core/lib/support/ref_counted.h
@@ -0,0 +1,122 @@
+/*
+ *
+ * Copyright 2017 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_REF_COUNTED_H
+#define GRPC_CORE_LIB_SUPPORT_REF_COUNTED_H
+
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/support/debug_location.h"
+#include "src/core/lib/support/memory.h"
+
+namespace grpc_core {
+
+// A base class for reference-counted objects.
+// New objects should be created via New() and start with a refcount of 1.
+// When the refcount reaches 0, the object will be deleted via Delete().
+class RefCounted {
+ public:
+  void Ref() { gpr_ref(&refs_); }
+
+  void Unref() {
+    if (gpr_unref(&refs_)) {
+      Delete(this);
+    }
+  }
+
+  // Not copyable nor movable.
+  RefCounted(const RefCounted&) = delete;
+  RefCounted& operator=(const RefCounted&) = delete;
+
+ protected:
+  // Allow Delete() to access destructor.
+  template <typename T>
+  friend void Delete(T*);
+
+  RefCounted() { gpr_ref_init(&refs_, 1); }
+
+  virtual ~RefCounted() {}
+
+ private:
+  gpr_refcount refs_;
+};
+
+// An alternative version of the RefCounted base class that
+// supports tracing.  This is intended to be used in cases where the
+// object will be handled both by idiomatic C++ code using smart
+// pointers and legacy code that is manually calling Ref() and Unref().
+// Once all of our code is converted to idiomatic C++, we may be able to
+// eliminate this class.
+class RefCountedWithTracing {
+ public:
+  void Ref() { gpr_ref(&refs_); }
+
+  void Ref(const DebugLocation& location, const char* reason) {
+    if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) {
+      gpr_atm old_refs = gpr_atm_no_barrier_load(&refs_.count);
+      gpr_log(GPR_DEBUG, "%s:%p %s:%d ref %" PRIdPTR " -> %" PRIdPTR " %s",
+              trace_flag_->name(), this, location.file(), location.line(),
+              old_refs, old_refs + 1, reason);
+    }
+    Ref();
+  }
+
+  void Unref() {
+    if (gpr_unref(&refs_)) {
+      Delete(this);
+    }
+  }
+
+  void Unref(const DebugLocation& location, const char* reason) {
+    if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) {
+      gpr_atm old_refs = gpr_atm_no_barrier_load(&refs_.count);
+      gpr_log(GPR_DEBUG, "%s:%p %s:%d unref %" PRIdPTR " -> %" PRIdPTR " %s",
+              trace_flag_->name(), this, location.file(), location.line(),
+              old_refs, old_refs - 1, reason);
+    }
+    Unref();
+  }
+
+  // Not copyable nor movable.
+  RefCountedWithTracing(const RefCountedWithTracing&) = delete;
+  RefCountedWithTracing& operator=(const RefCountedWithTracing&) = delete;
+
+ protected:
+  // Allow Delete() to access destructor.
+  template <typename T>
+  friend void Delete(T*);
+
+  RefCountedWithTracing() : RefCountedWithTracing(nullptr) {}
+
+  explicit RefCountedWithTracing(TraceFlag* trace_flag)
+      : trace_flag_(trace_flag) {
+    gpr_ref_init(&refs_, 1);
+  }
+
+  virtual ~RefCountedWithTracing() {}
+
+ private:
+  TraceFlag* trace_flag_ = nullptr;
+  gpr_refcount refs_;
+};
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_LIB_SUPPORT_REF_COUNTED_H */
diff --git a/src/core/lib/support/ref_counted_ptr.h b/src/core/lib/support/ref_counted_ptr.h
new file mode 100644
index 0000000000..dc2385e369
--- /dev/null
+++ b/src/core/lib/support/ref_counted_ptr.h
@@ -0,0 +1,90 @@
+/*
+ *
+ * Copyright 2017 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_REF_COUNTED_PTR_H
+#define GRPC_CORE_LIB_SUPPORT_REF_COUNTED_PTR_H
+
+#include <utility>
+
+#include "src/core/lib/support/memory.h"
+
+namespace grpc_core {
+
+// A smart pointer class for objects that provide Ref() and Unref() methods,
+// such as those provided by the RefCounted base class.
+template <typename T>
+class RefCountedPtr {
+ public:
+  RefCountedPtr() {}
+
+  // If value is non-null, we take ownership of a ref to it.
+  explicit RefCountedPtr(T* value) { value_ = value; }
+
+  // Move support.
+  RefCountedPtr(RefCountedPtr&& other) {
+    value_ = other.value_;
+    other.value_ = nullptr;
+  }
+  RefCountedPtr& operator=(RefCountedPtr&& other) {
+    if (value_ != nullptr) value_->Unref();
+    value_ = other.value_;
+    other.value_ = nullptr;
+    return *this;
+  }
+
+  // Copy support.
+  RefCountedPtr(const RefCountedPtr& other) {
+    if (other.value_ != nullptr) other.value_->Ref();
+    value_ = other.value_;
+  }
+  RefCountedPtr& operator=(const RefCountedPtr& other) {
+    // Note: Order of reffing and unreffing is important here in case value_
+    // and other.value_ are the same object.
+    if (other.value_ != nullptr) other.value_->Ref();
+    if (value_ != nullptr) value_->Unref();
+    value_ = other.value_;
+    return *this;
+  }
+
+  ~RefCountedPtr() {
+    if (value_ != nullptr) value_->Unref();
+  }
+
+  // If value is non-null, we take ownership of a ref to it.
+  void reset(T* value = nullptr) {
+    if (value_ != nullptr) value_->Unref();
+    value_ = value;
+  }
+
+  T* get() const { return value_; }
+
+  T& operator*() const { return *value_; }
+  T* operator->() const { return value_; }
+
+ private:
+  T* value_ = nullptr;
+};
+
+template <typename T, typename... Args>
+inline RefCountedPtr<T> MakeRefCounted(Args&&... args) {
+  return RefCountedPtr<T>(New<T>(std::forward<Args>(args)...));
+}
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_LIB_SUPPORT_REF_COUNTED_PTR_H */
diff --git a/test/core/support/BUILD b/test/core/support/BUILD
index 996166a371..32b64d4b8e 100644
--- a/test/core/support/BUILD
+++ b/test/core/support/BUILD
@@ -223,3 +223,30 @@ grpc_cc_test(
         "//test/core/util:gpr_test_util",
     ],
 )
+
+grpc_cc_test(
+    name = "ref_counted_test",
+    srcs = ["ref_counted_test.cc"],
+    language = "C++",
+    deps = [
+        "//:ref_counted",
+        "//test/core/util:gpr_test_util",
+    ],
+    external_deps = [
+        "gtest",
+    ],
+)
+
+grpc_cc_test(
+    name = "ref_counted_ptr_test",
+    srcs = ["ref_counted_ptr_test.cc"],
+    language = "C++",
+    deps = [
+        "//:ref_counted",
+        "//:ref_counted_ptr",
+        "//test/core/util:gpr_test_util",
+    ],
+    external_deps = [
+        "gtest",
+    ],
+)
diff --git a/test/core/support/ref_counted_ptr_test.cc b/test/core/support/ref_counted_ptr_test.cc
new file mode 100644
index 0000000000..1830edc4e5
--- /dev/null
+++ b/test/core/support/ref_counted_ptr_test.cc
@@ -0,0 +1,172 @@
+/*
+ *
+ * Copyright 2017 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.
+ *
+ */
+
+#include "src/core/lib/support/ref_counted_ptr.h"
+
+#include <gtest/gtest.h>
+
+#include <grpc/support/log.h>
+
+#include "src/core/lib/support/memory.h"
+#include "src/core/lib/support/ref_counted.h"
+#include "test/core/util/test_config.h"
+
+namespace grpc_core {
+namespace testing {
+namespace {
+
+class Foo : public RefCounted {
+ public:
+  Foo() : value_(0) {}
+
+  explicit Foo(int value) : value_(value) {}
+
+  int value() const { return value_; }
+
+ private:
+  int value_;
+};
+
+TEST(RefCountedPtr, DefaultConstructor) { RefCountedPtr<Foo> foo; }
+
+TEST(RefCountedPtr, ExplicitConstructorEmpty) {
+  RefCountedPtr<Foo> foo(nullptr);
+}
+
+TEST(RefCountedPtr, ExplicitConstructor) { RefCountedPtr<Foo> foo(New<Foo>()); }
+
+TEST(RefCountedPtr, MoveConstructor) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  RefCountedPtr<Foo> foo2(std::move(foo));
+  EXPECT_EQ(nullptr, foo.get());
+  EXPECT_NE(nullptr, foo2.get());
+}
+
+TEST(RefCountedPtr, MoveAssignment) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  RefCountedPtr<Foo> foo2 = std::move(foo);
+  EXPECT_EQ(nullptr, foo.get());
+  EXPECT_NE(nullptr, foo2.get());
+}
+
+TEST(RefCountedPtr, CopyConstructor) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  RefCountedPtr<Foo> foo2(foo);
+  EXPECT_NE(nullptr, foo.get());
+  EXPECT_EQ(foo.get(), foo2.get());
+}
+
+TEST(RefCountedPtr, CopyAssignment) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  RefCountedPtr<Foo> foo2 = foo;
+  EXPECT_NE(nullptr, foo.get());
+  EXPECT_EQ(foo.get(), foo2.get());
+}
+
+TEST(RefCountedPtr, CopyAssignmentWhenEmpty) {
+  RefCountedPtr<Foo> foo;
+  RefCountedPtr<Foo> foo2;
+  foo2 = foo;
+  EXPECT_EQ(nullptr, foo.get());
+  EXPECT_EQ(nullptr, foo2.get());
+}
+
+TEST(RefCountedPtr, CopyAssignmentToSelf) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  foo = foo;
+}
+
+TEST(RefCountedPtr, EnclosedScope) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  {
+    RefCountedPtr<Foo> foo2(std::move(foo));
+    EXPECT_EQ(nullptr, foo.get());
+    EXPECT_NE(nullptr, foo2.get());
+  }
+  EXPECT_EQ(nullptr, foo.get());
+}
+
+TEST(RefCountedPtr, ResetFromNullToNonNull) {
+  RefCountedPtr<Foo> foo;
+  EXPECT_EQ(nullptr, foo.get());
+  foo.reset(New<Foo>());
+  EXPECT_NE(nullptr, foo.get());
+}
+
+TEST(RefCountedPtr, ResetFromNonNullToNonNull) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  EXPECT_NE(nullptr, foo.get());
+  Foo* original = foo.get();
+  foo.reset(New<Foo>());
+  EXPECT_NE(nullptr, foo.get());
+  EXPECT_NE(original, foo.get());
+}
+
+TEST(RefCountedPtr, ResetFromNonNullToNull) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  EXPECT_NE(nullptr, foo.get());
+  foo.reset();
+  EXPECT_EQ(nullptr, foo.get());
+}
+
+TEST(RefCountedPtr, ResetFromNullToNull) {
+  RefCountedPtr<Foo> foo;
+  EXPECT_EQ(nullptr, foo.get());
+  foo.reset(nullptr);
+  EXPECT_EQ(nullptr, foo.get());
+}
+
+TEST(RefCountedPtr, DerefernceOperators) {
+  RefCountedPtr<Foo> foo(New<Foo>());
+  foo->value();
+  Foo& foo_ref = *foo;
+  foo_ref.value();
+}
+
+TEST(MakeRefCounted, NoArgs) {
+  RefCountedPtr<Foo> foo = MakeRefCounted<Foo>();
+  EXPECT_EQ(0, foo->value());
+}
+
+TEST(MakeRefCounted, Args) {
+  RefCountedPtr<Foo> foo = MakeRefCounted<Foo>(3);
+  EXPECT_EQ(3, foo->value());
+}
+
+TraceFlag foo_tracer(true, "foo");
+
+class FooWithTracing : public RefCountedWithTracing {
+ public:
+  FooWithTracing() : RefCountedWithTracing(&foo_tracer) {}
+};
+
+TEST(RefCountedPtr, RefCountedWithTracing) {
+  RefCountedPtr<FooWithTracing> foo(New<FooWithTracing>());
+  foo->Ref(DEBUG_LOCATION, "foo");
+  foo->Unref(DEBUG_LOCATION, "foo");
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace grpc_core
+
+int main(int argc, char** argv) {
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/test/core/support/ref_counted_test.cc b/test/core/support/ref_counted_test.cc
new file mode 100644
index 0000000000..be9b6ff7c2
--- /dev/null
+++ b/test/core/support/ref_counted_test.cc
@@ -0,0 +1,72 @@
+/*
+ *
+ * Copyright 2017 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.
+ *
+ */
+
+#include "src/core/lib/support/ref_counted.h"
+
+#include <gtest/gtest.h>
+
+#include "src/core/lib/support/memory.h"
+#include "test/core/util/test_config.h"
+
+namespace grpc_core {
+namespace testing {
+namespace {
+
+class Foo : public RefCounted {
+ public:
+  Foo() {}
+};
+
+TEST(RefCounted, Basic) {
+  Foo* foo = New<Foo>();
+  foo->Unref();
+}
+
+TEST(RefCounted, ExtraRef) {
+  Foo* foo = New<Foo>();
+  foo->Ref();
+  foo->Unref();
+  foo->Unref();
+}
+
+TraceFlag foo_tracer(true, "foo");
+
+class FooWithTracing : public RefCountedWithTracing {
+ public:
+  FooWithTracing() : RefCountedWithTracing(&foo_tracer) {}
+};
+
+TEST(RefCountedWithTracing, Basic) {
+  FooWithTracing* foo = New<FooWithTracing>();
+  foo->Ref(DEBUG_LOCATION, "extra_ref");
+  foo->Unref(DEBUG_LOCATION, "extra_ref");
+  // Can use the no-argument methods, too.
+  foo->Ref();
+  foo->Unref();
+  foo->Unref(DEBUG_LOCATION, "original_ref");
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace grpc_core
+
+int main(int argc, char** argv) {
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 6f38aae546..09f668d847 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -1033,12 +1033,15 @@ src/core/lib/support/arena.h \
 src/core/lib/support/atomic.h \
 src/core/lib/support/atomic_with_atm.h \
 src/core/lib/support/atomic_with_std.h \
+src/core/lib/support/debug_location.h \
 src/core/lib/support/env.h \
 src/core/lib/support/fork.h \
 src/core/lib/support/manual_constructor.h \
 src/core/lib/support/memory.h \
 src/core/lib/support/mpscq.h \
 src/core/lib/support/murmur_hash.h \
+src/core/lib/support/ref_counted.h \
+src/core/lib/support/ref_counted_ptr.h \
 src/core/lib/support/spinlock.h \
 src/core/lib/support/string.h \
 src/core/lib/support/string_windows.h \
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 77da92616e..28b7d396e0 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1287,6 +1287,7 @@ src/core/lib/support/cpu_iphone.cc \
 src/core/lib/support/cpu_linux.cc \
 src/core/lib/support/cpu_posix.cc \
 src/core/lib/support/cpu_windows.cc \
+src/core/lib/support/debug_location.h \
 src/core/lib/support/env.h \
 src/core/lib/support/env_linux.cc \
 src/core/lib/support/env_posix.cc \
@@ -1306,6 +1307,8 @@ src/core/lib/support/mpscq.cc \
 src/core/lib/support/mpscq.h \
 src/core/lib/support/murmur_hash.cc \
 src/core/lib/support/murmur_hash.h \
+src/core/lib/support/ref_counted.h \
+src/core/lib/support/ref_counted_ptr.h \
 src/core/lib/support/spinlock.h \
 src/core/lib/support/string.cc \
 src/core/lib/support/string.h \
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index c7d21c6c1a..c868acf8d3 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -3908,6 +3908,44 @@
       "gpr_test_util", 
       "grpc", 
       "grpc++", 
+      "grpc++_test", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "ref_counted_ptr_test", 
+    "src": [
+      "test/core/support/ref_counted_ptr_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
+      "grpc++_test", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "ref_counted_test", 
+    "src": [
+      "test/core/support/ref_counted_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
       "grpc++_test_util", 
       "grpc_test_util"
     ], 
@@ -8193,6 +8231,9 @@
       "src/core/lib/slice/slice_hash_table.h", 
       "src/core/lib/slice/slice_internal.h", 
       "src/core/lib/slice/slice_string_helpers.h", 
+      "src/core/lib/support/debug_location.h", 
+      "src/core/lib/support/ref_counted.h", 
+      "src/core/lib/support/ref_counted_ptr.h", 
       "src/core/lib/surface/alarm_internal.h", 
       "src/core/lib/surface/api_trace.h", 
       "src/core/lib/surface/call.h", 
@@ -8329,6 +8370,9 @@
       "src/core/lib/slice/slice_hash_table.h", 
       "src/core/lib/slice/slice_internal.h", 
       "src/core/lib/slice/slice_string_helpers.h", 
+      "src/core/lib/support/debug_location.h", 
+      "src/core/lib/support/ref_counted.h", 
+      "src/core/lib/support/ref_counted_ptr.h", 
       "src/core/lib/surface/alarm_internal.h", 
       "src/core/lib/surface/api_trace.h", 
       "src/core/lib/surface/call.h", 
diff --git a/tools/run_tests/generated/tests.json b/tools/run_tests/generated/tests.json
index 36b32605b8..929ed15918 100644
--- a/tools/run_tests/generated/tests.json
+++ b/tools/run_tests/generated/tests.json
@@ -4114,6 +4114,54 @@
     "flaky": false, 
     "gtest": true, 
     "language": "c++", 
+    "name": "ref_counted_ptr_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "uses_polling": true
+  }, 
+  {
+    "args": [], 
+    "benchmark": false, 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": true, 
+    "language": "c++", 
+    "name": "ref_counted_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "uses_polling": true
+  }, 
+  {
+    "args": [], 
+    "benchmark": false, 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": true, 
+    "language": "c++", 
     "name": "secure_auth_context_test", 
     "platforms": [
       "linux",