shaka-packager/tools/gn/function_read_file.cc

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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/file_util.h"
#include "tools/gn/err.h"
#include "tools/gn/filesystem_utils.h"
#include "tools/gn/functions.h"
#include "tools/gn/input_conversion.h"
#include "tools/gn/input_file.h"
#include "tools/gn/scheduler.h"
// TODO(brettw) consider removing this. I originally wrote it for making the
// WebKit bindings but misundersood what was required, and didn't need to
// use this. This seems to have a high potential for misuse.
namespace functions {
const char kReadFile[] = "read_file";
const char kReadFile_Help[] =
"read_file: Read a file into a variable.\n"
"\n"
" read_file(filename, how_to_read)\n"
"\n"
" Whitespace will be trimmed from the end of the file. Throws an error\n"
" if the file can not be opened.\n"
"\n"
"Arguments:\n"
"\n"
" filename\n"
" Filename to read, relative to the build file.\n"
"\n"
" input_conversion\n"
" Controls how the file is read and parsed.\n"
" See \"gn help input_conversion\".\n"
"\n"
"Example:\n"
" lines = read_file(\"foo.txt\", \"list lines\")\n";
Value RunReadFile(Scope* scope,
const FunctionCallNode* function,
const std::vector<Value>& args,
Err* err) {
if (args.size() != 2) {
*err = Err(function->function(), "Wrong number of args to read_file",
"I expected two arguments.");
return Value();
}
if (!args[0].VerifyTypeIs(Value::STRING, err))
return Value();
// Compute the file name.
const SourceDir& cur_dir = SourceDirForFunctionCall(function);
SourceFile source_file = cur_dir.ResolveRelativeFile(args[0].string_value());
base::FilePath file_path =
scope->settings()->build_settings()->GetFullPath(source_file);
// Ensure that everything is recomputed if the read file changes.
g_scheduler->AddGenDependency(file_path);
// Read contents.
std::string file_contents;
if (!file_util::ReadFileToString(file_path, &file_contents)) {
*err = Err(args[0], "Could not read file.",
"I resolved this to \"" + FilePathToUTF8(file_path) + "\".");
return Value();
}
return ConvertInputToValue(file_contents, function, args[1], err);
}
} // namespace functions