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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2025
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/utils/filesystem.h"
#include "td/utils/buffer.h"
#include "td/utils/misc.h"
#include "td/utils/PathView.h"
#include "td/utils/port/FileFd.h"
#include "td/utils/port/path.h"
#include "td/utils/Slice.h"
#include "td/utils/SliceBuilder.h"
#include "td/utils/Status.h"
#include "td/utils/unicode.h"
#include "td/utils/utf8.h"
namespace td {
namespace {
template <class T>
T create_empty(size_t size);
template <>
string create_empty<string>(size_t size) {
return string(size, '\0');
}
template <>
BufferSlice create_empty<BufferSlice>(size_t size) {
return BufferSlice{size};
}
template <>
SecureString create_empty<SecureString>(size_t size) {
return SecureString{size};
}
template <class T>
Result<T> read_file_impl(CSlice path, int64 size, int64 offset) {
TRY_RESULT(from_file, FileFd::open(path, FileFd::Read));
TRY_RESULT(file_size, from_file.get_size());
if (offset < 0 || offset > file_size) {
return Status::Error("Failed to read file: invalid offset");
}
if (size < 0 || size > file_size - offset) {
size = file_size - offset;
}
auto content = create_empty<T>(narrow_cast<size_t>(size));
TRY_RESULT(read_size, from_file.pread(as_mutable_slice(content), offset));
if (read_size != static_cast<size_t>(size)) {
return Status::Error("Failed to read file");
}
from_file.close();
return std::move(content);
}
} // namespace
Result<BufferSlice> read_file(CSlice path, int64 size, int64 offset) {
return read_file_impl<BufferSlice>(path, size, offset);
}
Result<string> read_file_str(CSlice path, int64 size, int64 offset) {
return read_file_impl<string>(path, size, offset);
}
Result<SecureString> read_file_secure(CSlice path, int64 size, int64 offset) {
return read_file_impl<SecureString>(path, size, offset);
}
// Very straightforward function. Don't expect much of it.
Status copy_file(CSlice from, CSlice to, int64 size) {
TRY_RESULT(content, read_file(from, size));
return write_file(to, content.as_slice());
}
Status write_file(CSlice to, Slice data, WriteFileOptions options) {
auto size = data.size();
TRY_RESULT(to_file, FileFd::open(to, FileFd::Truncate | FileFd::Create | FileFd::Write));
if (options.need_lock) {
TRY_STATUS(to_file.lock(FileFd::LockFlags::Write, to.str(), 10));
TRY_STATUS(to_file.truncate_to_current_position(0));
}
TRY_RESULT(written, to_file.write(data));
if (written != size) {
return Status::Error(PSLICE() << "Failed to write file: written " << written << " bytes instead of " << size);
}
if (options.need_sync) {
TRY_STATUS(to_file.sync());
}
if (options.need_lock) {
to_file.lock(FileFd::LockFlags::Unlock, to.str(), 10).ignore();
}
to_file.close();
return Status::OK();
}
static string clean_filename_part(Slice name, int max_length) {
auto is_ok = [](uint32 code) {
if (code < 32) {
return false;
}
if (code < 127) {
switch (code) {
case '<':
case '>':
case ':':
case '"':
case '/':
case '\\':
case '|':
case '?':
case '*':
case '&':
case '`':
case '\'':
return false;
default:
return true;
}
}
auto category = get_unicode_simple_category(code);
return category == UnicodeSimpleCategory::Letter || category == UnicodeSimpleCategory::DecimalNumber ||
category == UnicodeSimpleCategory::Number;
};
std::string new_name;
int size = 0;
for (auto *it = name.ubegin(); it != name.uend() && size < max_length;) {
uint32 code;
it = next_utf8_unsafe(it, &code);
if (!is_ok(code)) {
if (prepare_search_character(code) == 0) {
continue;
}
code = ' ';
}
if (new_name.empty() && (code == ' ' || code == '.')) {
continue;
}
append_utf8_character(new_name, code);
size++;
}
while (!new_name.empty() && (new_name.back() == ' ' || new_name.back() == '.')) {
new_name.pop_back();
}
return new_name;
}
string clean_filename(CSlice name) {
if (!check_utf8(name)) {
return {};
}
PathView path_view(name);
auto filename = clean_filename_part(path_view.file_stem(), 64);
auto extension = clean_filename_part(path_view.extension(), 16);
if (!extension.empty()) {
if (filename.empty()) {
filename = std::move(extension);
} else {
filename.reserve(filename.size() + 1 + extension.size());
filename += '.';
filename += extension;
}
}
return filename;
}
Status atomic_write_file(CSlice path, Slice data, CSlice path_tmp) {
string path_tmp_buf;
if (path_tmp.empty()) {
path_tmp_buf = path.str() + ".tmp";
path_tmp = path_tmp_buf;
}
WriteFileOptions options;
options.need_sync = true;
options.need_lock = true;
TRY_STATUS(write_file(path_tmp, data, options));
return rename(path_tmp, path);
}
} // namespace td
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