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/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_Help[] =
21    "read_file: Read a file into a variable.\n"
22    "\n"
23    "  read_file(filename, how_to_read)\n"
24    "\n"
25    "  Whitespace will be trimmed from the end of the file. Throws an error\n"
26    "  if the file can not be opened.\n"
27    "\n"
28    "Arguments:\n"
29    "\n"
30    "  filename\n"
31    "      Filename to read, relative to the build file.\n"
32    "\n"
33    "  input_conversion\n"
34    "      Controls how the file is read and parsed.\n"
35    "      See \"gn help input_conversion\".\n"
36    "\n"
37    "Example:\n"
38    "  lines = read_file(\"foo.txt\", \"list lines\")\n";
39
40Value RunReadFile(Scope* scope,
41                  const FunctionCallNode* function,
42                  const std::vector<Value>& args,
43                  Err* err) {
44  if (args.size() != 2) {
45    *err = Err(function->function(), "Wrong number of args to read_file",
46               "I expected two arguments.");
47    return Value();
48  }
49  if (!args[0].VerifyTypeIs(Value::STRING, err))
50    return Value();
51
52  // Compute the file name.
53  const SourceDir& cur_dir = SourceDirForFunctionCall(function);
54  SourceFile source_file = cur_dir.ResolveRelativeFile(args[0].string_value());
55  base::FilePath file_path =
56      scope->settings()->build_settings()->GetFullPath(source_file);
57
58  // Ensure that everything is recomputed if the read file changes.
59  g_scheduler->AddGenDependency(source_file);
60
61  // Read contents.
62  std::string file_contents;
63  if (!file_util::ReadFileToString(file_path, &file_contents)) {
64    *err = Err(args[0], "Could not read file.",
65               "I resolved this to \"" + FilePathToUTF8(file_path) + "\".");
66    return Value();
67  }
68
69  return ConvertInputToValue(file_contents, function, args[1], err);
70}
71
72}  // namespace functions
73