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
17 namespace functions {
18
19 const char kReadFile[] = "read_file";
20 const 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
RunReadFile(Scope * scope,const FunctionCallNode * function,const std::vector<Value> & args,Err * err)40 Value 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 = scope->GetSourceDir();
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(file_path);
60
61 // Read contents.
62 std::string file_contents;
63 if (!base::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