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