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1 // Copyright 2011 The Chromium Authors
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_VLOG_H_
6 #define BASE_VLOG_H_
7 
8 #include <string>
9 #include <vector>
10 
11 #include "base/base_export.h"
12 #include "base/memory/raw_ptr.h"
13 #include "base/strings/string_piece.h"
14 
15 namespace logging {
16 
17 // A helper class containing all the settings for vlogging.
18 class BASE_EXPORT VlogInfo {
19  public:
20   static const int kDefaultVlogLevel;
21 
22   // |v_switch| gives the default maximal active V-logging level; 0 is
23   // the default.  Normally positive values are used for V-logging
24   // levels.
25   //
26   // |vmodule_switch| gives the per-module maximal V-logging levels to
27   // override the value given by |v_switch|.
28   // E.g. "my_module=2,foo*=3" would change the logging level for all
29   // code in source files "my_module.*" and "foo*.*" ("-inl" suffixes
30   // are also disregarded for this matching).
31   //
32   // |min_log_level| points to an int that stores the log level. If a valid
33   // |v_switch| is provided, it will set the log level, and the default
34   // vlog severity will be read from there.
35   //
36   // Any pattern containing a forward or backward slash will be tested
37   // against the whole pathname and not just the module.  E.g.,
38   // "*/foo/bar/*=2" would change the logging level for all code in
39   // source files under a "foo/bar" directory.
40   VlogInfo(const std::string& v_switch,
41            const std::string& vmodule_switch,
42            int* min_log_level);
43   VlogInfo(const VlogInfo&) = delete;
44   VlogInfo& operator=(const VlogInfo&) = delete;
45   ~VlogInfo();
46 
47   // Returns the vlog level for a given file (usually taken from
48   // __FILE__).
49   int GetVlogLevel(base::StringPiece file) const;
50 
51   // Returns a new VlogInfo based on |this| but with extra modules/levels added
52   // according to |vmodule_switch|.
53   VlogInfo* WithSwitches(const std::string& vmodule_switch) const;
54 
55  private:
56   void SetMaxVlogLevel(int level);
57   int GetMaxVlogLevel() const;
58 
59   // VmodulePattern holds all the information for each pattern parsed
60   // from |vmodule_switch|.
61   struct VmodulePattern {
62     enum MatchTarget { MATCH_MODULE, MATCH_FILE };
63 
64     explicit VmodulePattern(const std::string& pattern);
65 
66     VmodulePattern();
67 
68     std::string pattern;
69     int vlog_level;
70     MatchTarget match_target;
71   };
72 
73   VlogInfo(std::vector<VmodulePattern> vmodule_levels, int* min_log_level);
74 
75   // Parses `VmodulePatterns` from a string, typically provided on the
76   // commandline.
77   static std::vector<VmodulePattern> ParseVmoduleLevels(
78       const std::string& vmodule_switch);
79 
80   const std::vector<VmodulePattern> vmodule_levels_;
81   raw_ptr<int> const min_log_level_;
82 };
83 
84 // Returns true if the string passed in matches the vlog pattern.  The
85 // vlog pattern string can contain wildcards like * and ?.  ? matches
86 // exactly one character while * matches 0 or more characters.  Also,
87 // as a special case, a / or \ character matches either / or \.
88 //
89 // Examples:
90 //   "kh?n" matches "khan" but not "khn" or "khaan"
91 //   "kh*n" matches "khn", "khan", or even "khaaaaan"
92 //   "/foo\bar" matches "/foo/bar", "\foo\bar", or "/foo\bar"
93 //     (disregarding C escaping rules)
94 BASE_EXPORT bool MatchVlogPattern(base::StringPiece string,
95                                   base::StringPiece vlog_pattern);
96 
97 }  // namespace logging
98 
99 #endif  // BASE_VLOG_H_
100