| /* |
| * |
| * 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_GPRPP_ORPHANABLE_H |
| #define GRPC_CORE_LIB_GPRPP_ORPHANABLE_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <grpc/support/log.h> |
| #include <grpc/support/sync.h> |
| |
| #include <cinttypes> |
| #include <memory> |
| |
| #include "src/core/lib/debug/trace.h" |
| #include "src/core/lib/gprpp/abstract.h" |
| #include "src/core/lib/gprpp/debug_location.h" |
| #include "src/core/lib/gprpp/memory.h" |
| #include "src/core/lib/gprpp/ref_counted_ptr.h" |
| |
| namespace grpc_core { |
| |
| // A base class for orphanable objects, which have one external owner |
| // but are not necessarily destroyed immediately when the external owner |
| // gives up ownership. Instead, the owner calls the object's Orphan() |
| // method, and the object then takes responsibility for its own cleanup |
| // and destruction. |
| class Orphanable { |
| public: |
| // Gives up ownership of the object. The implementation must arrange |
| // to eventually destroy the object without further interaction from the |
| // caller. |
| virtual void Orphan() GRPC_ABSTRACT; |
| |
| // Not copyable or movable. |
| Orphanable(const Orphanable&) = delete; |
| Orphanable& operator=(const Orphanable&) = delete; |
| |
| GRPC_ABSTRACT_BASE_CLASS |
| |
| protected: |
| Orphanable() {} |
| virtual ~Orphanable() {} |
| }; |
| |
| template <typename T> |
| class OrphanableDelete { |
| public: |
| void operator()(T* p) { p->Orphan(); } |
| }; |
| |
| template <typename T, typename Deleter = OrphanableDelete<T>> |
| using OrphanablePtr = std::unique_ptr<T, Deleter>; |
| |
| template <typename T, typename... Args> |
| inline OrphanablePtr<T> MakeOrphanable(Args&&... args) { |
| return OrphanablePtr<T>(New<T>(std::forward<Args>(args)...)); |
| } |
| |
| // A type of Orphanable with internal ref-counting. |
| template <typename Child> |
| class InternallyRefCounted : public Orphanable { |
| public: |
| // Not copyable nor movable. |
| InternallyRefCounted(const InternallyRefCounted&) = delete; |
| InternallyRefCounted& operator=(const InternallyRefCounted&) = delete; |
| |
| GRPC_ABSTRACT_BASE_CLASS |
| |
| protected: |
| GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_DELETE |
| |
| // Allow RefCountedPtr<> to access Unref() and IncrementRefCount(). |
| template <typename T> |
| friend class RefCountedPtr; |
| |
| InternallyRefCounted() { gpr_ref_init(&refs_, 1); } |
| virtual ~InternallyRefCounted() {} |
| |
| RefCountedPtr<Child> Ref() GRPC_MUST_USE_RESULT { |
| IncrementRefCount(); |
| return RefCountedPtr<Child>(static_cast<Child*>(this)); |
| } |
| |
| void Unref() { |
| if (gpr_unref(&refs_)) { |
| Delete(static_cast<Child*>(this)); |
| } |
| } |
| |
| private: |
| void IncrementRefCount() { gpr_ref(&refs_); } |
| |
| gpr_refcount refs_; |
| }; |
| |
| // An alternative version of the InternallyRefCounted 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. |
| template <typename Child> |
| class InternallyRefCountedWithTracing : public Orphanable { |
| public: |
| // Not copyable nor movable. |
| InternallyRefCountedWithTracing(const InternallyRefCountedWithTracing&) = |
| delete; |
| InternallyRefCountedWithTracing& operator=( |
| const InternallyRefCountedWithTracing&) = delete; |
| |
| GRPC_ABSTRACT_BASE_CLASS |
| |
| protected: |
| GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_DELETE |
| |
| // Allow RefCountedPtr<> to access Unref() and IncrementRefCount(). |
| template <typename T> |
| friend class RefCountedPtr; |
| |
| InternallyRefCountedWithTracing() |
| : InternallyRefCountedWithTracing(static_cast<TraceFlag*>(nullptr)) {} |
| |
| explicit InternallyRefCountedWithTracing(TraceFlag* trace_flag) |
| : trace_flag_(trace_flag) { |
| gpr_ref_init(&refs_, 1); |
| } |
| |
| #ifdef NDEBUG |
| explicit InternallyRefCountedWithTracing(DebugOnlyTraceFlag* trace_flag) |
| : InternallyRefCountedWithTracing() {} |
| #endif |
| |
| virtual ~InternallyRefCountedWithTracing() {} |
| |
| RefCountedPtr<Child> Ref() GRPC_MUST_USE_RESULT { |
| IncrementRefCount(); |
| return RefCountedPtr<Child>(static_cast<Child*>(this)); |
| } |
| |
| RefCountedPtr<Child> Ref(const DebugLocation& location, |
| const char* reason) GRPC_MUST_USE_RESULT { |
| if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { |
| gpr_atm old_refs = gpr_atm_no_barrier_load(&refs_.count); |
| gpr_log(GPR_INFO, "%s:%p %s:%d ref %" PRIdPTR " -> %" PRIdPTR " %s", |
| trace_flag_->name(), this, location.file(), location.line(), |
| old_refs, old_refs + 1, reason); |
| } |
| return Ref(); |
| } |
| |
| // TODO(roth): Once all of our code is converted to C++ and can use |
| // RefCountedPtr<> instead of manual ref-counting, make the Unref() methods |
| // private, since they will only be used by RefCountedPtr<>, which is a |
| // friend of this class. |
| |
| void Unref() { |
| if (gpr_unref(&refs_)) { |
| Delete(static_cast<Child*>(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_INFO, "%s:%p %s:%d unref %" PRIdPTR " -> %" PRIdPTR " %s", |
| trace_flag_->name(), this, location.file(), location.line(), |
| old_refs, old_refs - 1, reason); |
| } |
| Unref(); |
| } |
| |
| private: |
| void IncrementRefCount() { gpr_ref(&refs_); } |
| |
| TraceFlag* trace_flag_ = nullptr; |
| gpr_refcount refs_; |
| }; |
| |
| } // namespace grpc_core |
| |
| #endif /* GRPC_CORE_LIB_GPRPP_ORPHANABLE_H */ |