tools/gn/source_dir.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_SOURCE_DIR_H_
   6 #define TOOLS_GN_SOURCE_DIR_H_
   7
   8 #include <algorithm>
   9 #include <string>
  10
  11 #include "base/containers/hash_tables.h"
  12 #include "base/files/file_path.h"
  13 #include "base/logging.h"
  14 #include "base/strings/string_piece.h"
  15
  16 class SourceFile;
  17
  18 // Represents a directory within the source tree. Source dirs begin and end in
  19 // slashes.
  20 //
  21 // If there is one slash at the beginning, it will mean a system-absolute file
  22 // path. On Windows, absolute system paths will be of the form "/C:/foo/bar".
  23 //
  24 // Two slashes at the beginning indicate a path relative to the source root.
  25 class SourceDir {
  26  public:
  27   enum SwapIn { SWAP_IN };
  28
  29   SourceDir();
  30   explicit SourceDir(const base::StringPiece& p);
  31   // Swaps the given string in without copies. The given string will be empty
  32   // after this call.
  33   SourceDir(SwapIn, std::string* s);
  34   ~SourceDir();
  35
  36   // Resolves a file or dir name relative to this source directory. Will return
  37   // an empty SourceDir/File on error. Empty input is always an error (it's
  38   // possible we should say ResolveRelativeDir vs. an empty string should be
  39   // the source dir, but we require "." instead).
  40   //
  41   // If source_root is supplied, these functions will additionally handle the
  42   // case where the input is a system-absolute but still inside the source
  43   // tree. This is the case for some external tools.
  44   SourceFile ResolveRelativeFile(
  45       const base::StringPiece& p,
  46       const base::StringPiece& source_root = base::StringPiece()) const;
  47   SourceDir ResolveRelativeDir(
  48       const base::StringPiece& p,
  49       const base::StringPiece& source_root = base::StringPiece()) const;
  50
  51   // Resolves this source file relative to some given source root. Returns
  52   // an empty file path on error.
  53   base::FilePath Resolve(const base::FilePath& source_root) const;
  54
  55   bool is_null() const { return value_.empty(); }
  56   const std::string& value() const { return value_; }
  57
  58   // Returns true if this path starts with a "//" which indicates a path
  59   // from the source root.
  60   bool is_source_absolute() const {
  61     return value_.size() >= 2 && value_[0] == '/' && value_[1] == '/';
  62   }
  63
  64   // Returns true if this path starts with a single slash which indicates a
  65   // system-absolute path.
  66   bool is_system_absolute() const {
  67     return !is_source_absolute();
  68   }
  69
  70   // Returns a source-absolute path starting with only one slash at the
  71   // beginning (normally source-absolute paths start with two slashes to mark
  72   // them as such). This is normally used when concatenating directories
  73   // together.
  74   //
  75   // This function asserts that the directory is actually source-absolute. The
  76   // return value points into our buffer.
  77   base::StringPiece SourceAbsoluteWithOneSlash() const {
  78     CHECK(is_source_absolute());
  79     return base::StringPiece(&value_[1], value_.size() - 1);
  80   }
  81
  82   void SwapValue(std::string* v);
  83
  84   bool operator==(const SourceDir& other) const {
  85     return value_ == other.value_;
  86   }
  87   bool operator!=(const SourceDir& other) const {
  88     return !operator==(other);
  89   }
  90   bool operator<(const SourceDir& other) const {
  91     return value_ < other.value_;
  92   }
  93
  94   void swap(SourceDir& other) {
  95     value_.swap(other.value_);
  96   }
  97
  98  private:
  99   friend class SourceFile;
 100   std::string value_;
 101
 102   // Copy & assign supported.
 103 };
 104
 105 namespace BASE_HASH_NAMESPACE {
 106
 107 template<> struct hash<SourceDir> {
 108   std::size_t operator()(const SourceDir& v) const {
 109     hash<std::string> h;
 110     return h(v.value());
 111   }
 112 };
 113
 114 }  // namespace BASE_HASH_NAMESPACE
 115
 116 inline void swap(SourceDir& lhs, SourceDir& rhs) {
 117   lhs.swap(rhs);
 118 }
 119
 120 #endif  // TOOLS_GN_SOURCE_DIR_H_