Add ReferenceCounted base class.

3 files changed, 161 insertions, 0 deletions

diff --git a/src/core/lib/support/debug_location.h b/src/core/lib/support/debug_location.h
new file mode 100644
index 0000000000..9260752d5e
--- /dev/null
+++ b/src/core/lib/support/debug_location.h
@@ -0,0 +1,48 @@
+/*
+ *
+ * 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 {
+
+#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/reference_counted.cc b/src/core/lib/support/reference_counted.cc
new file mode 100644
index 0000000000..853a29da2f
--- /dev/null
+++ b/src/core/lib/support/reference_counted.cc
@@ -0,0 +1,58 @@
+/*
+ *
+ * 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/reference_counted.h"
+
+#include <grpc/support/log.h>
+
+namespace grpc_core {
+
+void ReferenceCounted::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 ReferenceCounted::Ref() {
+  gpr_ref(&refs_);
+}
+
+bool ReferenceCounted::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);
+  }
+  return Unref();
+}
+
+bool ReferenceCounted::Unref() {
+  if (gpr_unref(&refs_)) {
+    delete this;
+    return true;
+  }
+  return false;
+}
+
+}  // namespace grpc_core
diff --git a/src/core/lib/support/reference_counted.h b/src/core/lib/support/reference_counted.h
new file mode 100644
index 0000000000..ebd620c553
--- /dev/null
+++ b/src/core/lib/support/reference_counted.h
@@ -0,0 +1,55 @@
+/*
+ *
+ * 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_REFERENCE_COUNTED_H
+#define GRPC_CORE_LIB_SUPPORT_REFERENCE_COUNTED_H
+
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/support/debug_location.h"
+
+namespace grpc_core {
+
+class ReferenceCounted {
+ public:
+  void Ref();
+  void Ref(const DebugLocation& location, const char* reason);
+
+  bool Unref();
+  bool Unref(const DebugLocation& location, const char* reason);
+
+  // Not copyable nor movable.
+  ReferenceCounted(const ReferenceCounted&) = delete;
+  ReferenceCounted& operator=(const ReferenceCounted&) = delete;
+
+ protected:
+  explicit ReferenceCounted(TraceFlag* trace_flag) : trace_flag_(trace_flag) {
+    gpr_ref_init(&refs_, 1);
+  }
+
+  virtual ~ReferenceCounted() {}
+
+ private:
+  TraceFlag* trace_flag_;
+  gpr_refcount refs_;
+};
+
+}  // namespace grpc_core
+
+#endif // GRPC_CORE_LIB_SUPPORT_REFERENCE_COUNTED_H