Mark D. Roth | 324703d | 2018-01-11 07:41:31 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2017 gRPC authors. |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #ifndef GRPC_CORE_LIB_SUPPORT_ORPHANABLE_H |
| 20 | #define GRPC_CORE_LIB_SUPPORT_ORPHANABLE_H |
| 21 | |
| 22 | #include <grpc/support/log.h> |
| 23 | #include <grpc/support/sync.h> |
| 24 | |
| 25 | #include <memory> |
| 26 | |
| 27 | #include "src/core/lib/debug/trace.h" |
| 28 | #include "src/core/lib/support/abstract.h" |
| 29 | #include "src/core/lib/support/debug_location.h" |
| 30 | #include "src/core/lib/support/memory.h" |
| 31 | |
| 32 | namespace grpc_core { |
| 33 | |
| 34 | // A base class for orphanable objects. |
| 35 | class Orphanable { |
| 36 | public: |
| 37 | // Gives up ownership of the object. The implementation must arrange |
| 38 | // to destroy the object without further interaction from the caller. |
| 39 | virtual void Orphan() GRPC_ABSTRACT; |
| 40 | |
| 41 | // Not copyable or movable. |
| 42 | Orphanable(const Orphanable&) = delete; |
| 43 | Orphanable& operator=(const Orphanable&) = delete; |
| 44 | |
| 45 | GRPC_ABSTRACT_BASE_CLASS |
| 46 | |
| 47 | protected: |
| 48 | Orphanable() {} |
| 49 | virtual ~Orphanable() {} |
| 50 | }; |
| 51 | |
| 52 | template <typename T> |
| 53 | class OrphanableDelete { |
| 54 | public: |
| 55 | void operator()(T* p) { p->Orphan(); } |
| 56 | }; |
| 57 | |
| 58 | template <typename T, typename Deleter = OrphanableDelete<T>> |
| 59 | using OrphanablePtr = std::unique_ptr<T, Deleter>; |
| 60 | |
| 61 | template <typename T, typename... Args> |
| 62 | inline OrphanablePtr<T> MakeOrphanable(Args&&... args) { |
| 63 | return OrphanablePtr<T>(New<T>(std::forward<Args>(args)...)); |
| 64 | } |
| 65 | |
| 66 | // A type of Orphanable with internal ref-counting. |
| 67 | class InternallyRefCounted : public Orphanable { |
| 68 | public: |
| 69 | // Not copyable nor movable. |
| 70 | InternallyRefCounted(const InternallyRefCounted&) = delete; |
| 71 | InternallyRefCounted& operator=(const InternallyRefCounted&) = delete; |
| 72 | |
| 73 | GRPC_ABSTRACT_BASE_CLASS |
| 74 | |
| 75 | protected: |
| 76 | InternallyRefCounted() { gpr_ref_init(&refs_, 1); } |
| 77 | virtual ~InternallyRefCounted() {} |
| 78 | |
| 79 | void Ref() { gpr_ref(&refs_); } |
| 80 | |
| 81 | void Unref() { |
| 82 | if (gpr_unref(&refs_)) { |
| 83 | Delete(this); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | // Allow Delete() to access destructor. |
| 88 | template <typename T> |
| 89 | friend void Delete(T*); |
| 90 | |
| 91 | private: |
| 92 | gpr_refcount refs_; |
| 93 | }; |
| 94 | |
| 95 | // An alternative version of the InternallyRefCounted base class that |
| 96 | // supports tracing. This is intended to be used in cases where the |
| 97 | // object will be handled both by idiomatic C++ code using smart |
| 98 | // pointers and legacy code that is manually calling Ref() and Unref(). |
| 99 | // Once all of our code is converted to idiomatic C++, we may be able to |
| 100 | // eliminate this class. |
| 101 | class InternallyRefCountedWithTracing : public Orphanable { |
| 102 | public: |
| 103 | // Not copyable nor movable. |
| 104 | InternallyRefCountedWithTracing(const InternallyRefCountedWithTracing&) = |
| 105 | delete; |
| 106 | InternallyRefCountedWithTracing& operator=( |
| 107 | const InternallyRefCountedWithTracing&) = delete; |
| 108 | |
| 109 | GRPC_ABSTRACT_BASE_CLASS |
| 110 | |
| 111 | protected: |
| 112 | // Allow Delete() to access destructor. |
| 113 | template <typename T> |
| 114 | friend void Delete(T*); |
| 115 | |
| 116 | InternallyRefCountedWithTracing() |
| 117 | : InternallyRefCountedWithTracing(static_cast<TraceFlag*>(nullptr)) {} |
| 118 | |
| 119 | explicit InternallyRefCountedWithTracing(TraceFlag* trace_flag) |
| 120 | : trace_flag_(trace_flag) { |
| 121 | gpr_ref_init(&refs_, 1); |
| 122 | } |
| 123 | |
| 124 | #ifdef NDEBUG |
| 125 | explicit InternallyRefCountedWithTracing(DebugOnlyTraceFlag* trace_flag) |
| 126 | : InternallyRefCountedWithTracing() {} |
| 127 | #endif |
| 128 | |
| 129 | virtual ~InternallyRefCountedWithTracing() {} |
| 130 | |
| 131 | void Ref() { gpr_ref(&refs_); } |
| 132 | |
| 133 | void Ref(const DebugLocation& location, const char* reason) { |
| 134 | if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { |
| 135 | gpr_atm old_refs = gpr_atm_no_barrier_load(&refs_.count); |
| 136 | gpr_log(GPR_DEBUG, "%s:%p %s:%d ref %" PRIdPTR " -> %" PRIdPTR " %s", |
| 137 | trace_flag_->name(), this, location.file(), location.line(), |
| 138 | old_refs, old_refs + 1, reason); |
| 139 | } |
| 140 | Ref(); |
| 141 | } |
| 142 | |
| 143 | void Unref() { |
| 144 | if (gpr_unref(&refs_)) { |
| 145 | Delete(this); |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | void Unref(const DebugLocation& location, const char* reason) { |
| 150 | if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { |
| 151 | gpr_atm old_refs = gpr_atm_no_barrier_load(&refs_.count); |
| 152 | gpr_log(GPR_DEBUG, "%s:%p %s:%d unref %" PRIdPTR " -> %" PRIdPTR " %s", |
| 153 | trace_flag_->name(), this, location.file(), location.line(), |
| 154 | old_refs, old_refs - 1, reason); |
| 155 | } |
| 156 | Unref(); |
| 157 | } |
| 158 | |
| 159 | private: |
| 160 | TraceFlag* trace_flag_ = nullptr; |
| 161 | gpr_refcount refs_; |
| 162 | }; |
| 163 | |
| 164 | } // namespace grpc_core |
| 165 | |
| 166 | #endif /* GRPC_CORE_LIB_SUPPORT_ORPHANABLE_H */ |