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 "base/files/file_util.h"
6#include "tools/gn/err.h"
7#include "tools/gn/filesystem_utils.h"
8#include "tools/gn/functions.h"
9#include "tools/gn/input_conversion.h"
10#include "tools/gn/input_file.h"
11#include "tools/gn/scheduler.h"
12
13// TODO(brettw) consider removing this. I originally wrote it for making the
14// WebKit bindings but misundersood what was required, and didn't need to
15// use this. This seems to have a high potential for misuse.
16
17namespace functions {
18
19const char kReadFile[] = "read_file";
20const char kReadFile_HelpShort[] =
21    "read_file: Read a file into a variable.";
22const char kReadFile_Help[] =
23    "read_file: Read a file into a variable.\n"
24    "\n"
25    "  read_file(filename, input_conversion)\n"
26    "\n"
27    "  Whitespace will be trimmed from the end of the file. Throws an error\n"
28    "  if the file can not be opened.\n"
29    "\n"
30    "Arguments:\n"
31    "\n"
32    "  filename\n"
33    "      Filename to read, relative to the build file.\n"
34    "\n"
35    "  input_conversion\n"
36    "      Controls how the file is read and parsed.\n"
37    "      See \"gn help input_conversion\".\n"
38    "\n"
39    "Example\n"
40    "  lines = read_file(\"foo.txt\", \"list lines\")\n";
41
42Value RunReadFile(Scope* scope,
43                  const FunctionCallNode* function,
44                  const std::vector<Value>& args,
45                  Err* err) {
46  if (args.size() != 2) {
47    *err = Err(function->function(), "Wrong number of arguments to read_file",
48               "I expected two arguments.");
49    return Value();
50  }
51  if (!args[0].VerifyTypeIs(Value::STRING, err))
52    return Value();
53
54  // Compute the file name.
55  const SourceDir& cur_dir = scope->GetSourceDir();
56  SourceFile source_file = cur_dir.ResolveRelativeFile(args[0].string_value());
57  base::FilePath file_path =
58      scope->settings()->build_settings()->GetFullPath(source_file);
59
60  // Ensure that everything is recomputed if the read file changes.
61  g_scheduler->AddGenDependency(file_path);
62
63  // Read contents.
64  std::string file_contents;
65  if (!base::ReadFileToString(file_path, &file_contents)) {
66    *err = Err(args[0], "Could not read file.",
67               "I resolved this to \"" + FilePathToUTF8(file_path) + "\".");
68    return Value();
69  }
70
71  return ConvertInputToValue(scope->settings(), file_contents, function,
72                             args[1], err);
73}
74
75}  // namespace functions
76