tools/gn/function_write_file.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 <iostream>
   6 #include <sstream>
   7
   8 #include "base/files/file_util.h"
   9 #include "base/strings/string_split.h"
  10 #include "base/strings/string_util.h"
  11 #include "tools/gn/err.h"
  12 #include "tools/gn/filesystem_utils.h"
  13 #include "tools/gn/functions.h"
  14 #include "tools/gn/input_file.h"
  15 #include "tools/gn/parse_tree.h"
  16 #include "tools/gn/scheduler.h"
  17
  18 namespace functions {
  19
  20 const char kWriteFile[] = "write_file";
  21 const char kWriteFile_HelpShort[] =
  22     "write_file: Write a file to disk.";
  23 const char kWriteFile_Help[] =
  24     "write_file: Write a file to disk.\n"
  25     "\n"
  26     "  write_file(filename, data)\n"
  27     "\n"
  28     "  If data is a list, the list will be written one-item-per-line with no\n"
  29     "  quoting or brackets.\n"
  30     "\n"
  31     "  If the file exists and the contents are identical to that being\n"
  32     "  written, the file will not be updated. This will prevent unnecessary\n"
  33     "  rebuilds of targets that depend on this file.\n"
  34     "\n"
  35     "  TODO(brettw) we probably need an optional third argument to control\n"
  36     "  list formatting.\n"
  37     "\n"
  38     "Arguments:\n"
  39     "\n"
  40     "  filename\n"
  41     "      Filename to write. This must be within the output directory.\n"
  42     "\n"
  43     "  data:\n"
  44     "      The list or string to write.\n";
  45
  46 Value RunWriteFile(Scope* scope,
  47                    const FunctionCallNode* function,
  48                    const std::vector<Value>& args,
  49                    Err* err) {
  50   if (args.size() != 2) {
  51     *err = Err(function->function(), "Wrong number of arguments to write_file",
  52                "I expected two arguments.");
  53     return Value();
  54   }
  55
  56   // Compute the file name and make sure it's in the output dir.
  57   if (!args[0].VerifyTypeIs(Value::STRING, err))
  58     return Value();
  59   const SourceDir& cur_dir = scope->GetSourceDir();
  60   SourceFile source_file = cur_dir.ResolveRelativeFile(args[0].string_value());
  61   if (!EnsureStringIsInOutputDir(
  62           scope->settings()->build_settings()->build_dir(),
  63           source_file.value(), args[0].origin(), err))
  64     return Value();
  65
  66   // Compute output.
  67   std::ostringstream contents;
  68   if (args[1].type() == Value::LIST) {
  69     const std::vector<Value>& list = args[1].list_value();
  70     for (size_t i = 0; i < list.size(); i++)
  71       contents << list[i].ToString(false) << std::endl;
  72   } else {
  73     contents << args[1].ToString(false);
  74   }
  75   const std::string& new_contents = contents.str();
  76   base::FilePath file_path =
  77       scope->settings()->build_settings()->GetFullPath(source_file);
  78
  79   // Make sure we're not replacing the same contents.
  80   std::string existing_contents;
  81   if (base::ReadFileToString(file_path, &existing_contents) &&
  82       existing_contents == new_contents)
  83     return Value();  // Nothing to do.
  84
  85   // Write file, creating the directory if necessary.
  86   if (!base::CreateDirectory(file_path.DirName())) {
  87     *err = Err(function->function(), "Unable to create directory.",
  88                "I was using \"" + FilePathToUTF8(file_path.DirName()) + "\".");
  89     return Value();
  90   }
  91
  92   int int_size = static_cast<int>(new_contents.size());
  93   if (base::WriteFile(file_path, new_contents.c_str(), int_size)
  94       != int_size) {
  95     *err = Err(function->function(), "Unable to write file.",
  96                "I was writing \"" + FilePathToUTF8(file_path) + "\".");
  97     return Value();
  98   }
  99   return Value();
 100 }
 101
 102 }  // namespace functions