tools/gn/label.h

   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 "base/containers/hash_tables.h"
   9 #include "tools/gn/source_dir.h"
  10
  11 class Err;
  12 class Value;
  13
  14 // A label represents the name of a target or some other named thing in
  15 // the source path. The label is always absolute and always includes a name
  16 // part, so it starts with a slash, and has one colon.
  17 class Label {
  18  public:
  19   Label();
  20
  21   // Makes a label given an already-separated out path and name.
  22   // See also Resolve().
  23   Label(const SourceDir& dir,
  24         const base::StringPiece& name,
  25         const SourceDir& toolchain_dir,
  26         const base::StringPiece& toolchain_name);
  27
  28   // Makes a label with an empty toolchain.
  29   Label(const SourceDir& dir, const base::StringPiece& name);
  30   ~Label();
  31
  32   // Resolives a string from a build file that may be relative to the
  33   // current directory into a fully qualified label. On failure returns an
  34   // is_null() label and sets the error.
  35   static Label Resolve(const SourceDir& current_dir,
  36                        const Label& current_toolchain,
  37                        const Value& input,
  38                        Err* err);
  39
  40   bool is_null() const { return dir_.is_null(); }
  41
  42   const SourceDir& dir() const { return dir_; }
  43   const std::string& name() const { return name_; }
  44
  45   const SourceDir& toolchain_dir() const { return toolchain_dir_; }
  46   const std::string& toolchain_name() const { return toolchain_name_; }
  47
  48   // Returns the current label's toolchain as its own Label.
  49   Label GetToolchainLabel() const;
  50
  51   // Returns a copy of this label but with an empty toolchain.
  52   Label GetWithNoToolchain() const;
  53
  54   // Formats this label in a way that we can present to the user or expose to
  55   // other parts of the system. SourceDirs end in slashes, but the user
  56   // expects names like "//chrome/renderer:renderer_config" when printed. The
  57   // toolchain is optionally included.
  58   std::string GetUserVisibleName(bool include_toolchain) const;
  59
  60   // Like the above version, but automatically includes the toolchain if it's
  61   // not the default one. Normally the user only cares about the toolchain for
  62   // non-default ones, so this can make certain output more clear.
  63   std::string GetUserVisibleName(const Label& default_toolchain) const;
  64
  65   bool operator==(const Label& other) const {
  66     return name_ == other.name_ && dir_ == other.dir_ &&
  67            toolchain_dir_ == other.toolchain_dir_ &&
  68            toolchain_name_ == other.toolchain_name_;
  69   }
  70   bool operator!=(const Label& other) const {
  71     return !operator==(other);
  72   }
  73   bool operator<(const Label& other) const {
  74     // TODO(brettw) could be optimized to avoid an extra full string check
  75     // (one for operator==, one for <).
  76     if (dir_ != other.dir_)
  77       return dir_ < other.dir_;
  78     if (name_ != other.name_)
  79       return name_ < other.name_;
  80     if (toolchain_dir_ != other.toolchain_dir_)
  81       return toolchain_dir_ < other.toolchain_dir_;
  82     return toolchain_name_ < other.toolchain_name_;
  83   }
  84
  85   void swap(Label& other) {
  86     dir_.swap(other.dir_);
  87     name_.swap(other.name_);
  88     toolchain_dir_.swap(other.toolchain_dir_);
  89     toolchain_name_.swap(other.toolchain_name_);
  90   }
  91
  92   // Returns true if the toolchain dir/name of this object matches some
  93   // other object.
  94   bool ToolchainsEqual(const Label& other) const {
  95     return toolchain_dir_ == other.toolchain_dir_ &&
  96            toolchain_name_ == other.toolchain_name_;
  97   }
  98
  99  private:
 100   SourceDir dir_;
 101   std::string name_;
 102
 103   SourceDir toolchain_dir_;
 104   std::string toolchain_name_;
 105 };
 106
 107 namespace BASE_HASH_NAMESPACE {
 108
 109 template<> struct hash<Label> {
 110   std::size_t operator()(const Label& v) const {
 111     hash<std::string> stringhash;
 112     return ((stringhash(v.dir().value()) * 131 +
 113              stringhash(v.name())) * 131 +
 114             stringhash(v.toolchain_dir().value())) * 131 +
 115            stringhash(v.toolchain_name());
 116   }
 117 };
 118
 119 }  // namespace BASE_HASH_NAMESPACE
 120
 121 inline void swap(Label& lhs, Label& rhs) {
 122   lhs.swap(rhs);
 123 }
 124
 125 #endif  // TOOLS_GN_LABEL_H_