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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ | 5 #ifndef TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ |
6 #define TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ | 6 #define TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ |
7 | 7 |
8 // TracingStatus is a four-point value ordered by | 8 // TracingStatus is a three-point value ordered by unneeded < unknown < needed. |
9 // illegal < unneeded < unknown < needed | |
10 // | |
11 // It is used to categorize tracing of fields: | |
12 // | |
13 // * illegal field is invalid/illegal to trace. | |
14 // * unneeded field has type with no traceable fields of its own; | |
15 // it may have an empty trace() method. Not harmful | |
16 // to trace, but not needed. | |
17 // * unknown initial TracingStatus value. | |
18 // * needed field is a heap reference or an object containing | |
19 // traceable fields. | |
20 // | |
21 // Tracing status |illegal| is considered an error; treating |unneeded| also | |
22 // as an error would detect and report unnecessary tracing of objects that | |
23 // probably don't need to be on the Blink GC heap. However, template use | |
24 // and instantiation can leave us with classes that do have empty trace | |
25 // methods and no traceable fields -- reporting these as errors/warnings | |
26 // wouldn't work. Hence, only consider |illegal| as an error TracingStatus | |
27 // state. | |
28 class TracingStatus { | 9 class TracingStatus { |
29 public: | 10 public: |
30 static TracingStatus Illegal() { return kIllegal; } | |
31 static TracingStatus Unneeded() { return kUnneeded; } | 11 static TracingStatus Unneeded() { return kUnneeded; } |
32 static TracingStatus Unknown() { return kUnknown; } | 12 static TracingStatus Unknown() { return kUnknown; } |
33 static TracingStatus Needed() { return kNeeded; } | 13 static TracingStatus Needed() { return kNeeded; } |
34 bool IsIllegal() const { return status_ == kIllegal; } | |
35 bool IsUnneeded() const { return status_ == kUnneeded; } | 14 bool IsUnneeded() const { return status_ == kUnneeded; } |
36 bool IsUnknown() const { return status_ == kUnknown; } | 15 bool IsUnknown() const { return status_ == kUnknown; } |
37 bool IsNeeded() const { return status_ == kNeeded; } | 16 bool IsNeeded() const { return status_ == kNeeded; } |
38 TracingStatus LUB(const TracingStatus& other) const { | 17 TracingStatus LUB(const TracingStatus& other) const { |
39 return status_ > other.status_ ? status_ : other.status_; | 18 return status_ > other.status_ ? status_ : other.status_; |
40 } | 19 } |
41 bool operator==(const TracingStatus& other) const { | 20 bool operator==(const TracingStatus& other) const { |
42 return status_ == other.status_; | 21 return status_ == other.status_; |
43 } | 22 } |
44 private: | 23 private: |
45 enum Status { kIllegal, kUnneeded, kUnknown, kNeeded }; | 24 enum Status { kUnneeded, kUnknown, kNeeded }; |
46 TracingStatus(Status status) : status_(status) {} | 25 TracingStatus(Status status) : status_(status) {} |
47 Status status_; | 26 Status status_; |
48 }; | 27 }; |
49 | 28 |
50 #endif // TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ | 29 #endif // TOOLS_BLINK_GC_PLUGIN_TRACING_STATUS_H_ |
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