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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef BASE_WIN_SCOPED_HANDLE_H_ | |
6 #define BASE_WIN_SCOPED_HANDLE_H_ | |
7 | |
8 #include <windows.h> | |
9 | |
10 #include "base/base_export.h" | |
11 #include "base/basictypes.h" | |
12 #include "base/location.h" | |
13 #include "base/logging.h" | |
14 #include "base/move.h" | |
15 | |
16 // TODO(rvargas): remove this with the rest of the verifier. | |
17 #if defined(COMPILER_MSVC) | |
18 #include <intrin.h> | |
19 #define BASE_WIN_GET_CALLER _ReturnAddress() | |
20 #elif defined(COMPILER_GCC) | |
21 #define BASE_WIN_GET_CALLER __builtin_extract_return_addr(\\ | |
22 __builtin_return_address(0)) | |
23 #endif | |
24 | |
25 namespace base { | |
26 namespace win { | |
27 | |
28 // Generic wrapper for raw handles that takes care of closing handles | |
29 // automatically. The class interface follows the style of | |
30 // the ScopedFILE class with one addition: | |
31 // - IsValid() method can tolerate multiple invalid handle values such as NULL | |
32 // and INVALID_HANDLE_VALUE (-1) for Win32 handles. | |
33 template <class Traits, class Verifier> | |
34 class GenericScopedHandle { | |
35 MOVE_ONLY_TYPE_FOR_CPP_03(GenericScopedHandle, RValue) | |
36 | |
37 public: | |
38 typedef typename Traits::Handle Handle; | |
39 | |
40 GenericScopedHandle() : handle_(Traits::NullHandle()) {} | |
41 | |
42 explicit GenericScopedHandle(Handle handle) : handle_(Traits::NullHandle()) { | |
43 Set(handle); | |
44 } | |
45 | |
46 // Move constructor for C++03 move emulation of this type. | |
47 GenericScopedHandle(RValue other) : handle_(Traits::NullHandle()) { | |
48 Set(other.object->Take()); | |
49 } | |
50 | |
51 ~GenericScopedHandle() { | |
52 Close(); | |
53 } | |
54 | |
55 bool IsValid() const { | |
56 return Traits::IsHandleValid(handle_); | |
57 } | |
58 | |
59 // Move operator= for C++03 move emulation of this type. | |
60 GenericScopedHandle& operator=(RValue other) { | |
61 if (this != other.object) { | |
62 Set(other.object->Take()); | |
63 } | |
64 return *this; | |
65 } | |
66 | |
67 void Set(Handle handle) { | |
68 if (handle_ != handle) { | |
69 Close(); | |
70 | |
71 if (Traits::IsHandleValid(handle)) { | |
72 handle_ = handle; | |
73 Verifier::StartTracking(handle, this, BASE_WIN_GET_CALLER, | |
74 tracked_objects::GetProgramCounter()); | |
75 } | |
76 } | |
77 } | |
78 | |
79 Handle Get() const { | |
80 return handle_; | |
81 } | |
82 | |
83 // Transfers ownership away from this object. | |
84 Handle Take() { | |
85 Handle temp = handle_; | |
86 handle_ = Traits::NullHandle(); | |
87 if (Traits::IsHandleValid(temp)) { | |
88 Verifier::StopTracking(temp, this, BASE_WIN_GET_CALLER, | |
89 tracked_objects::GetProgramCounter()); | |
90 } | |
91 return temp; | |
92 } | |
93 | |
94 // Explicitly closes the owned handle. | |
95 void Close() { | |
96 if (Traits::IsHandleValid(handle_)) { | |
97 Verifier::StopTracking(handle_, this, BASE_WIN_GET_CALLER, | |
98 tracked_objects::GetProgramCounter()); | |
99 | |
100 Traits::CloseHandle(handle_); | |
101 handle_ = Traits::NullHandle(); | |
102 } | |
103 } | |
104 | |
105 private: | |
106 Handle handle_; | |
107 }; | |
108 | |
109 #undef BASE_WIN_GET_CALLER | |
110 | |
111 // The traits class for Win32 handles that can be closed via CloseHandle() API. | |
112 class HandleTraits { | |
113 public: | |
114 typedef HANDLE Handle; | |
115 | |
116 // Closes the handle. | |
117 static bool BASE_EXPORT CloseHandle(HANDLE handle); | |
118 | |
119 // Returns true if the handle value is valid. | |
120 static bool IsHandleValid(HANDLE handle) { | |
121 return handle != NULL && handle != INVALID_HANDLE_VALUE; | |
122 } | |
123 | |
124 // Returns NULL handle value. | |
125 static HANDLE NullHandle() { | |
126 return NULL; | |
127 } | |
128 | |
129 private: | |
130 DISALLOW_IMPLICIT_CONSTRUCTORS(HandleTraits); | |
131 }; | |
132 | |
133 // Do-nothing verifier. | |
134 class DummyVerifierTraits { | |
135 public: | |
136 typedef HANDLE Handle; | |
137 | |
138 static void StartTracking(HANDLE handle, const void* owner, | |
139 const void* pc1, const void* pc2) {} | |
140 static void StopTracking(HANDLE handle, const void* owner, | |
141 const void* pc1, const void* pc2) {} | |
142 | |
143 private: | |
144 DISALLOW_IMPLICIT_CONSTRUCTORS(DummyVerifierTraits); | |
145 }; | |
146 | |
147 // Performs actual run-time tracking. | |
148 class BASE_EXPORT VerifierTraits { | |
149 public: | |
150 typedef HANDLE Handle; | |
151 | |
152 static void StartTracking(HANDLE handle, const void* owner, | |
153 const void* pc1, const void* pc2); | |
154 static void StopTracking(HANDLE handle, const void* owner, | |
155 const void* pc1, const void* pc2); | |
156 | |
157 private: | |
158 DISALLOW_IMPLICIT_CONSTRUCTORS(VerifierTraits); | |
159 }; | |
160 | |
161 typedef GenericScopedHandle<HandleTraits, VerifierTraits> ScopedHandle; | |
162 | |
163 // This function may be called by the embedder to disable the use of | |
164 // VerifierTraits at runtime. It has no effect if DummyVerifierTraits is used | |
165 // for ScopedHandle. | |
166 void BASE_EXPORT DisableHandleVerifier(); | |
167 | |
168 // This should be called whenever the OS is closing a handle, if extended | |
169 // verification of improper handle closing is desired. If |handle| is being | |
170 // tracked by the handle verifier and ScopedHandle is not the one closing it, | |
171 // a CHECK is generated. | |
172 void BASE_EXPORT OnHandleBeingClosed(HANDLE handle); | |
173 | |
174 } // namespace win | |
175 } // namespace base | |
176 | |
177 #endif // BASE_WIN_SCOPED_HANDLE_H_ | |
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