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