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