diff options
Diffstat (limited to 'src/core/lib/gprpp/ref_counted.h')
-rw-r--r-- | src/core/lib/gprpp/ref_counted.h | 159 |
1 files changed, 75 insertions, 84 deletions
diff --git a/src/core/lib/gprpp/ref_counted.h b/src/core/lib/gprpp/ref_counted.h index e366445bff..fa97ffcfed 100644 --- a/src/core/lib/gprpp/ref_counted.h +++ b/src/core/lib/gprpp/ref_counted.h @@ -21,6 +21,7 @@ #include <grpc/support/port_platform.h> +#include <grpc/support/atm.h> #include <grpc/support/log.h> #include <grpc/support/sync.h> @@ -73,31 +74,82 @@ class RefCount { using Value = intptr_t; // `init` is the initial refcount stored in this object. - constexpr explicit RefCount(Value init = 1) : value_(init) {} + // + // TraceFlagT is defined to accept both DebugOnlyTraceFlag and TraceFlag. + // Note: RefCount tracing is only enabled on debug builds, even when a + // TraceFlag is used. + template <typename TraceFlagT = TraceFlag> + constexpr explicit RefCount(Value init = 1, TraceFlagT* trace_flag = nullptr) + : +#ifndef NDEBUG + trace_flag_(trace_flag), +#endif + value_(init) { + } // Increases the ref-count by `n`. - void Ref(Value n = 1) { value_.fetch_add(n, std::memory_order_relaxed); } + void Ref(Value n = 1) { + GPR_ATM_INC_ADD_THEN(value_.fetch_add(n, std::memory_order_relaxed)); + } + void Ref(const DebugLocation& location, const char* reason, Value n = 1) { +#ifndef NDEBUG + if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { + const RefCount::Value old_refs = get(); + gpr_log(GPR_INFO, "%s:%p %s:%d ref %" PRIdPTR " -> %" PRIdPTR " %s", + trace_flag_->name(), this, location.file(), location.line(), + old_refs, old_refs + n, reason); + } +#endif + Ref(n); + } // Similar to Ref() with an assert on the ref-count being non-zero. void RefNonZero() { #ifndef NDEBUG - const Value prior = value_.fetch_add(1, std::memory_order_relaxed); + const Value prior = + GPR_ATM_INC_ADD_THEN(value_.fetch_add(1, std::memory_order_relaxed)); assert(prior > 0); #else Ref(); #endif } + void RefNonZero(const DebugLocation& location, const char* reason) { +#ifndef NDEBUG + if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { + const RefCount::Value old_refs = get(); + 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); + } +#endif + RefNonZero(); + } // Decrements the ref-count and returns true if the ref-count reaches 0. bool Unref() { - const Value prior = value_.fetch_sub(1, std::memory_order_acq_rel); + const Value prior = + GPR_ATM_INC_ADD_THEN(value_.fetch_sub(1, std::memory_order_acq_rel)); GPR_DEBUG_ASSERT(prior > 0); return prior == 1; } + bool Unref(const DebugLocation& location, const char* reason) { +#ifndef NDEBUG + if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { + const RefCount::Value old_refs = get(); + 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); + } +#endif + return Unref(); + } + private: Value get() const { return value_.load(std::memory_order_relaxed); } - private: +#ifndef NDEBUG + TraceFlag* trace_flag_; +#endif std::atomic<Value> value_; }; @@ -135,108 +187,45 @@ class RefCounted : public Impl { return RefCountedPtr<Child>(static_cast<Child*>(this)); } - // TODO(roth): Once all of our code is converted to C++ and can use - // RefCountedPtr<> instead of manual ref-counting, make this method - // private, since it will only be used by RefCountedPtr<>, which is a - // friend of this class. - void Unref() { - if (refs_.Unref()) { - Delete(static_cast<Child*>(this)); - } - } - - // Not copyable nor movable. - RefCounted(const RefCounted&) = delete; - RefCounted& operator=(const RefCounted&) = delete; - - GRPC_ABSTRACT_BASE_CLASS - - protected: - GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_DELETE - - RefCounted() = default; - - // Note: Depending on the Impl used, this dtor can be implicitly virtual. - ~RefCounted() = default; - - private: - // Allow RefCountedPtr<> to access IncrementRefCount(). - template <typename T> - friend class RefCountedPtr; - - void IncrementRefCount() { refs_.Ref(); } - - 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. -template <typename Child, typename Impl = PolymorphicRefCount> -class RefCountedWithTracing : public Impl { - public: - 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()) { - const RefCount::Value old_refs = refs_.get(); - 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(); + IncrementRefCount(location, reason); + return RefCountedPtr<Child>(static_cast<Child*>(this)); } // 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 + // RefCountedPtr<> instead of manual ref-counting, make this method + // private, since it will only be used by RefCountedPtr<>, which is a // friend of this class. - void Unref() { if (refs_.Unref()) { Delete(static_cast<Child*>(this)); } } - void Unref(const DebugLocation& location, const char* reason) { - if (location.Log() && trace_flag_ != nullptr && trace_flag_->enabled()) { - const RefCount::Value old_refs = refs_.get(); - 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); + if (refs_.Unref(location, reason)) { + Delete(static_cast<Child*>(this)); } - Unref(); } // Not copyable nor movable. - RefCountedWithTracing(const RefCountedWithTracing&) = delete; - RefCountedWithTracing& operator=(const RefCountedWithTracing&) = delete; + RefCounted(const RefCounted&) = delete; + RefCounted& operator=(const RefCounted&) = delete; GRPC_ABSTRACT_BASE_CLASS protected: GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_DELETE - RefCountedWithTracing() - : RefCountedWithTracing(static_cast<TraceFlag*>(nullptr)) {} - - explicit RefCountedWithTracing(TraceFlag* trace_flag) - : trace_flag_(trace_flag) {} - -#ifdef NDEBUG - explicit RefCountedWithTracing(DebugOnlyTraceFlag* trace_flag) - : RefCountedWithTracing() {} -#endif + // TraceFlagT is defined to accept both DebugOnlyTraceFlag and TraceFlag. + // Note: RefCount tracing is only enabled on debug builds, even when a + // TraceFlag is used. + template <typename TraceFlagT = TraceFlag> + explicit RefCounted(TraceFlagT* trace_flag = nullptr) + : refs_(1, trace_flag) {} // Note: Depending on the Impl used, this dtor can be implicitly virtual. - ~RefCountedWithTracing() = default; + ~RefCounted() = default; private: // Allow RefCountedPtr<> to access IncrementRefCount(). @@ -244,8 +233,10 @@ class RefCountedWithTracing : public Impl { friend class RefCountedPtr; void IncrementRefCount() { refs_.Ref(); } + void IncrementRefCount(const DebugLocation& location, const char* reason) { + refs_.Ref(location, reason); + } - TraceFlag* trace_flag_ = nullptr; RefCount refs_; }; |