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1 // Copyright (c) 2013 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 TOOLS_GN_LABEL_H_
6 #define TOOLS_GN_LABEL_H_
7 
8 #include <tuple>
9 
10 #include <stddef.h>
11 
12 #include "gn/source_dir.h"
13 
14 class Err;
15 class Value;
16 
17 // A label represents the name of a target or some other named thing in
18 // the source path. The label is always absolute and always includes a name
19 // part, so it starts with a slash, and has one colon.
20 class Label {
21  public:
22   Label() = default;
23 
24   // Makes a label given an already-separated out path and name.
25   // See also Resolve().
26   Label(const SourceDir& dir,
27         const std::string_view& name,
28         const SourceDir& toolchain_dir,
29         const std::string_view& toolchain_name);
30 
31   // Makes a label with an empty toolchain.
32   Label(const SourceDir& dir, const std::string_view& name);
33 
34   // Resolves a string from a build file that may be relative to the
35   // current directory into a fully qualified label. On failure returns an
36   // is_null() label and sets the error.
37   static Label Resolve(const SourceDir& current_dir,
38                        const std::string_view& source_root,
39                        const Label& current_toolchain,
40                        const Value& input,
41                        Err* err);
42 
is_null()43   bool is_null() const { return dir_.is_null(); }
44 
dir()45   const SourceDir& dir() const { return dir_; }
name()46   const std::string& name() const { return name_; }
47 
toolchain_dir()48   const SourceDir& toolchain_dir() const { return toolchain_dir_; }
toolchain_name()49   const std::string& toolchain_name() const { return toolchain_name_; }
50 
51   // Returns the current label's toolchain as its own Label.
52   Label GetToolchainLabel() const;
53 
54   // Returns a copy of this label but with an empty toolchain.
55   Label GetWithNoToolchain() const;
56 
57   // Formats this label in a way that we can present to the user or expose to
58   // other parts of the system. SourceDirs end in slashes, but the user
59   // expects names like "//chrome/renderer:renderer_config" when printed. The
60   // toolchain is optionally included.
61   std::string GetUserVisibleName(bool include_toolchain) const;
62 
63   // Like the above version, but automatically includes the toolchain if it's
64   // not the default one. Normally the user only cares about the toolchain for
65   // non-default ones, so this can make certain output more clear.
66   std::string GetUserVisibleName(const Label& default_toolchain) const;
67 
68   bool operator==(const Label& other) const {
69     return name_ == other.name_ && dir_ == other.dir_ &&
70            toolchain_dir_ == other.toolchain_dir_ &&
71            toolchain_name_ == other.toolchain_name_;
72   }
73   bool operator!=(const Label& other) const { return !operator==(other); }
74   bool operator<(const Label& other) const {
75     return std::tie(dir_, name_, toolchain_dir_, toolchain_name_) <
76            std::tie(other.dir_, other.name_, other.toolchain_dir_,
77                     other.toolchain_name_);
78   }
79 
80   // Returns true if the toolchain dir/name of this object matches some
81   // other object.
ToolchainsEqual(const Label & other)82   bool ToolchainsEqual(const Label& other) const {
83     return toolchain_dir_ == other.toolchain_dir_ &&
84            toolchain_name_ == other.toolchain_name_;
85   }
86 
87  private:
88   SourceDir dir_;
89   std::string name_;
90 
91   SourceDir toolchain_dir_;
92   std::string toolchain_name_;
93 };
94 
95 namespace std {
96 
97 template <>
98 struct hash<Label> {
99   std::size_t operator()(const Label& v) const {
100     hash<std::string> stringhash;
101     return ((stringhash(v.dir().value()) * 131 + stringhash(v.name())) * 131 +
102             stringhash(v.toolchain_dir().value())) *
103                131 +
104            stringhash(v.toolchain_name());
105   }
106 };
107 
108 }  // namespace std
109 
110 extern const char kLabels_Help[];
111 
112 #endif  // TOOLS_GN_LABEL_H_
113