tools/gn/function_rebase_path.cc

   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 #include "tools/gn/build_settings.h"
   6 #include "tools/gn/filesystem_utils.h"
   7 #include "tools/gn/functions.h"
   8 #include "tools/gn/parse_tree.h"
   9 #include "tools/gn/scope.h"
  10 #include "tools/gn/settings.h"
  11 #include "tools/gn/source_dir.h"
  12 #include "tools/gn/source_file.h"
  13 #include "tools/gn/value.h"
  14
  15 namespace functions {
  16
  17 namespace {
  18
  19 // We want the output to match the input in terms of ending in a slash or not.
  20 // Through all the transformations, these can get added or removed in various
  21 // cases.
  22 void MakeSlashEndingMatchInput(const std::string& input, std::string* output) {
  23   if (EndsWithSlash(input)) {
  24     if (!EndsWithSlash(*output))  // Preserve same slash type as input.
  25       output->push_back(input[input.size() - 1]);
  26   } else {
  27     if (EndsWithSlash(*output))
  28       output->resize(output->size() - 1);
  29   }
  30 }
  31
  32 // Returns true if the given value looks like a directory, otherwise we'll
  33 // assume it's a file.
  34 bool ValueLooksLikeDir(const std::string& value) {
  35   if (value.empty())
  36     return true;
  37   size_t value_size = value.size();
  38
  39   // Count the number of dots at the end of the string.
  40   size_t num_dots = 0;
  41   while (num_dots < value_size && value[value_size - num_dots - 1] == '.')
  42     num_dots++;
  43
  44   if (num_dots == value.size())
  45     return true;  // String is all dots.
  46
  47   if (IsSlash(value[value_size - num_dots - 1]))
  48     return true;  // String is a [back]slash followed by 0 or more dots.
  49
  50   // Anything else.
  51   return false;
  52 }
  53
  54 Value ConvertOnePath(const Scope* scope,
  55                      const FunctionCallNode* function,
  56                      const Value& value,
  57                      const SourceDir& from_dir,
  58                      const SourceDir& to_dir,
  59                      bool convert_to_system_absolute,
  60                      Err* err) {
  61   Value result;  // Ensure return value optimization.
  62
  63   if (!value.VerifyTypeIs(Value::STRING, err))
  64     return result;
  65   const std::string& string_value = value.string_value();
  66
  67   bool looks_like_dir = ValueLooksLikeDir(string_value);
  68
  69   // System-absolute output special case.
  70   if (convert_to_system_absolute) {
  71     base::FilePath system_path;
  72     if (looks_like_dir) {
  73       system_path = scope->settings()->build_settings()->GetFullPath(
  74           from_dir.ResolveRelativeDir(string_value,
  75               scope->settings()->build_settings()->root_path_utf8()));
  76     } else {
  77       system_path = scope->settings()->build_settings()->GetFullPath(
  78           from_dir.ResolveRelativeFile(string_value,
  79               scope->settings()->build_settings()->root_path_utf8()));
  80     }
  81     result = Value(function, FilePathToUTF8(system_path));
  82     if (looks_like_dir)
  83       MakeSlashEndingMatchInput(string_value, &result.string_value());
  84     return result;
  85   }
  86
  87   result = Value(function, Value::STRING);
  88   if (looks_like_dir) {
  89     result.string_value() = RebasePath(
  90         from_dir.ResolveRelativeDir(string_value,
  91             scope->settings()->build_settings()->root_path_utf8()).value(),
  92         to_dir,
  93         scope->settings()->build_settings()->root_path_utf8());
  94     MakeSlashEndingMatchInput(string_value, &result.string_value());
  95   } else {
  96     result.string_value() = RebasePath(
  97         from_dir.ResolveRelativeFile(string_value,
  98             scope->settings()->build_settings()->root_path_utf8()).value(),
  99         to_dir,
 100         scope->settings()->build_settings()->root_path_utf8());
 101   }
 102
 103   return result;
 104 }
 105
 106 }  // namespace
 107
 108 const char kRebasePath[] = "rebase_path";
 109 const char kRebasePath_HelpShort[] =
 110     "rebase_path: Rebase a file or directory to another location.";
 111 const char kRebasePath_Help[] =
 112     "rebase_path: Rebase a file or directory to another location.\n"
 113     "\n"
 114     "  converted = rebase_path(input,\n"
 115     "                          new_base = \"\",\n"
 116     "                          current_base = \".\")\n"
 117     "\n"
 118     "  Takes a string argument representing a file name, or a list of such\n"
 119     "  strings and converts it/them to be relative to a different base\n"
 120     "  directory.\n"
 121     "\n"
 122     "  When invoking the compiler or scripts, GN will automatically convert\n"
 123     "  sources and include directories to be relative to the build directory.\n"
 124     "  However, if you're passing files directly in the \"args\" array or\n"
 125     "  doing other manual manipulations where GN doesn't know something is\n"
 126     "  a file name, you will need to convert paths to be relative to what\n"
 127     "  your tool is expecting.\n"
 128     "\n"
 129     "  The common case is to use this to convert paths relative to the\n"
 130     "  current directory to be relative to the build directory (which will\n"
 131     "  be the current directory when executing scripts).\n"
 132     "\n"
 133     "  If you want to convert a file path to be source-absolute (that is,\n"
 134     "  beginning with a double slash like \"//foo/bar\"), you should use\n"
 135     "  the get_path_info() function. This function won't work because it will\n"
 136     "  always make relative paths, and it needs to support making paths\n"
 137     "  relative to the source root, so can't also generate source-absolute\n"
 138     "  paths without more special-cases.\n"
 139     "\n"
 140     "Arguments:\n"
 141     "\n"
 142     "  input\n"
 143     "      A string or list of strings representing file or directory names\n"
 144     "      These can be relative paths (\"foo/bar.txt\"), system absolute\n"
 145     "      paths (\"/foo/bar.txt\"), or source absolute paths\n"
 146     "      (\"//foo/bar.txt\").\n"
 147     "\n"
 148     "  new_base\n"
 149     "      The directory to convert the paths to be relative to. This can be\n"
 150     "      an absolute path or a relative path (which will be treated\n"
 151     "      as being relative to the current BUILD-file's directory).\n"
 152     "\n"
 153     "      As a special case, if new_base is the empty string (the default),\n"
 154     "      all paths will be converted to system-absolute native style paths\n"
 155     "      with system path separators. This is useful for invoking external\n"
 156     "      programs.\n"
 157     "\n"
 158     "  current_base\n"
 159     "      Directory representing the base for relative paths in the input.\n"
 160     "      If this is not an absolute path, it will be treated as being\n"
 161     "      relative to the current build file. Use \".\" (the default) to\n"
 162     "      convert paths from the current BUILD-file's directory.\n"
 163     "\n"
 164     "      On Posix systems there are no path separator transformations\n"
 165     "      applied. If the new_base is empty (specifying absolute output)\n"
 166     "      this parameter should not be supplied since paths will always be\n"
 167     "      converted,\n"
 168     "\n"
 169     "Return value\n"
 170     "\n"
 171     "  The return value will be the same type as the input value (either a\n"
 172     "  string or a list of strings). All relative and source-absolute file\n"
 173     "  names will be converted to be relative to the requested output\n"
 174     "  System-absolute paths will be unchanged.\n"
 175     "\n"
 176     "Example\n"
 177     "\n"
 178     "  # Convert a file in the current directory to be relative to the build\n"
 179     "  # directory (the current dir when executing compilers and scripts).\n"
 180     "  foo = rebase_path(\"myfile.txt\", root_build_dir)\n"
 181     "  # might produce \"../../project/myfile.txt\".\n"
 182     "\n"
 183     "  # Convert a file to be system absolute:\n"
 184     "  foo = rebase_path(\"myfile.txt\")\n"
 185     "  # Might produce \"D:\\source\\project\\myfile.txt\" on Windows or\n"
 186     "  # \"/home/you/source/project/myfile.txt\" on Linux.\n"
 187     "\n"
 188     "  # Typical usage for converting to the build directory for a script.\n"
 189     "  action(\"myscript\") {\n"
 190     "    # Don't convert sources, GN will automatically convert these to be\n"
 191     "    # relative to the build directory when it contructs the command\n"
 192     "    # line for your script.\n"
 193     "    sources = [ \"foo.txt\", \"bar.txt\" ]\n"
 194     "\n"
 195     "    # Extra file args passed manually need to be explicitly converted\n"
 196     "    # to be relative to the build directory:\n"
 197     "    args = [\n"
 198     "      \"--data\",\n"
 199     "      rebase_path(\"//mything/data/input.dat\", root_build_dir),\n"
 200     "      \"--rel\",\n"
 201     "      rebase_path(\"relative_path.txt\", root_build_dir)\n"
 202     "    ] + sources\n"
 203     "  }\n";
 204
 205 Value RunRebasePath(Scope* scope,
 206                     const FunctionCallNode* function,
 207                     const std::vector<Value>& args,
 208                     Err* err) {
 209   Value result;
 210
 211   // Argument indices.
 212   static const size_t kArgIndexInputs = 0;
 213   static const size_t kArgIndexDest = 1;
 214   static const size_t kArgIndexFrom = 2;
 215
 216   // Inputs.
 217   if (args.size() < 1 || args.size() > 3) {
 218     *err = Err(function->function(), "Wrong # of arguments for rebase_path.");
 219     return result;
 220   }
 221   const Value& inputs = args[kArgIndexInputs];
 222
 223   // To path.
 224   bool convert_to_system_absolute = true;
 225   SourceDir to_dir;
 226   const SourceDir& current_dir = scope->GetSourceDir();
 227   if (args.size() > kArgIndexDest) {
 228     if (!args[kArgIndexDest].VerifyTypeIs(Value::STRING, err))
 229       return result;
 230     if (!args[kArgIndexDest].string_value().empty()) {
 231       to_dir = current_dir.ResolveRelativeDir(
 232           args[kArgIndexDest].string_value(),
 233           scope->settings()->build_settings()->root_path_utf8());
 234       convert_to_system_absolute = false;
 235     }
 236   }
 237
 238   // From path.
 239   SourceDir from_dir;
 240   if (args.size() > kArgIndexFrom) {
 241     if (!args[kArgIndexFrom].VerifyTypeIs(Value::STRING, err))
 242       return result;
 243     from_dir = current_dir.ResolveRelativeDir(
 244         args[kArgIndexFrom].string_value(),
 245         scope->settings()->build_settings()->root_path_utf8());
 246   } else {
 247     // Default to current directory if unspecified.
 248     from_dir = current_dir;
 249   }
 250
 251   // Path conversion.
 252   if (inputs.type() == Value::STRING) {
 253     return ConvertOnePath(scope, function, inputs,
 254                           from_dir, to_dir, convert_to_system_absolute, err);
 255
 256   } else if (inputs.type() == Value::LIST) {
 257     result = Value(function, Value::LIST);
 258     result.list_value().reserve(inputs.list_value().size());
 259
 260     for (const auto& input : inputs.list_value()) {
 261       result.list_value().push_back(
 262           ConvertOnePath(scope, function, input,
 263                          from_dir, to_dir, convert_to_system_absolute, err));
 264       if (err->has_error()) {
 265         result = Value();
 266         return result;
 267       }
 268     }
 269     return result;
 270   }
 271
 272   *err = Err(function->function(),
 273              "rebase_path requires a list or a string.");
 274   return result;
 275 }
 276
 277 }  // namespace functions