1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
*
* 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_REF_COUNTED_H
#define GRPC_CORE_LIB_GPRPP_REF_COUNTED_H
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#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 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().
//
// This will commonly be used by CRTP (curiously-recurring template pattern)
// e.g., class MyClass : public RefCounted<MyClass>
template <typename Child>
class RefCounted {
public:
RefCountedPtr<Child> Ref() GRPC_MUST_USE_RESULT {
IncrementRefCount();
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 (gpr_unref(&refs_)) {
Delete(this);
}
}
// Not copyable nor movable.
RefCounted(const RefCounted&) = delete;
RefCounted& operator=(const RefCounted&) = delete;
GRPC_ABSTRACT_BASE_CLASS
protected:
// Allow Delete() to access destructor.
template <typename T>
friend void Delete(T*);
RefCounted() { gpr_ref_init(&refs_, 1); }
virtual ~RefCounted() {}
private:
// Allow RefCountedPtr<> to access IncrementRefCount().
friend class RefCountedPtr<Child>;
void IncrementRefCount() { gpr_ref(&refs_); }
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.
template <typename Child>
class RefCountedWithTracing {
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()) {
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);
}
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(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;
GRPC_ABSTRACT_BASE_CLASS
protected:
// Allow Delete() to access destructor.
template <typename T>
friend void Delete(T*);
RefCountedWithTracing()
: RefCountedWithTracing(static_cast<TraceFlag*>(nullptr)) {}
explicit RefCountedWithTracing(TraceFlag* trace_flag)
: trace_flag_(trace_flag) {
gpr_ref_init(&refs_, 1);
}
#ifdef NDEBUG
explicit RefCountedWithTracing(DebugOnlyTraceFlag* trace_flag)
: RefCountedWithTracing() {}
#endif
virtual ~RefCountedWithTracing() {}
private:
// Allow RefCountedPtr<> to access IncrementRefCount().
friend class RefCountedPtr<Child>;
void IncrementRefCount() { gpr_ref(&refs_); }
TraceFlag* trace_flag_ = nullptr;
gpr_refcount refs_;
};
} // namespace grpc_core
#endif /* GRPC_CORE_LIB_GPRPP_REF_COUNTED_H */
|
