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Telegram/SourceFiles/export/output/export_output_file.cpp

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+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "export/output/export_output_file.h"
+
+#include "export/output/export_output_result.h"
+#include "export/output/export_output_stats.h"
+#include "base/qt/qt_string_view.h"
+
+#include <QtCore/QFileInfo>
+#include <QtCore/QDir>
+
+#include <gsl/util>
+
+namespace Export {
+namespace Output {
+
+File::File(const QString &path, Stats *stats) : _path(path), _stats(stats) {
+}
+
+int64 File::size() const {
+	return _offset;
+}
+
+bool File::empty() const {
+	return !_offset;
+}
+
+Result File::writeBlock(const QByteArray &block) {
+	const auto result = writeBlockAttempt(block);
+	if (!result) {
+		_file.reset();
+	}
+	return result;
+}
+
+Result File::writeBlockAttempt(const QByteArray &block) {
+	if (_stats && !_inStats) {
+		_inStats = true;
+		_stats->incrementFiles();
+	}
+	if (const auto result = reopen(); !result) {
+		return result;
+	}
+	const auto size = block.size();
+	if (!size) {
+		return Result::Success();
+	}
+	if (_file->write(block) == size && _file->flush()) {
+		_offset += size;
+		if (_stats) {
+			_stats->incrementBytes(size);
+		}
+		return Result::Success();
+	}
+	return error();
+}
+
+Result File::reopen() {
+	if (_file && _file->isOpen()) {
+		return Result::Success();
+	}
+	_file.emplace(_path);
+	if (_file->exists()) {
+		if (_file->size() < _offset) {
+			return fatalError();
+		} else if (!_file->resize(_offset)) {
+			return error();
+		}
+	} else if (_offset > 0) {
+		return fatalError();
+	}
+	if (_file->open(QIODevice::Append)) {
+		return Result::Success();
+	}
+	const auto info = QFileInfo(_path);
+	const auto dir = info.absoluteDir();
+	return (!dir.exists()
+		&& dir.mkpath(dir.absolutePath())
+		&& _file->open(QIODevice::Append))
+		? Result::Success()
+		: error();
+}
+
+Result File::error() const {
+	return Result(Result::Type::Error, _path);
+}
+
+Result File::fatalError() const {
+	return Result(Result::Type::FatalError, _path);
+}
+
+QString File::PrepareRelativePath(
+		const QString &folder,
+		const QString &suggested) {
+	if (!QFile::exists(folder + suggested)) {
+		return suggested;
+	}
+
+	// Not lastIndexOf('.') so that "file.tar.xz" won't be messed up.
+	const auto position = suggested.indexOf('.');
+	const auto base = suggested.mid(0, position);
+	const auto extension = (position >= 0)
+		? base::StringViewMid(suggested, position)
+		: QStringView();
+	const auto relativePart = [&](int attempt) {
+		auto result = base + QString(" (%1)").arg(attempt);
+		result.append(extension);
+		return result;
+	};
+	auto attempt = 0;
+	while (true) {
+		const auto relativePath = relativePart(++attempt);
+		if (!QFile::exists(folder + relativePath)) {
+			return relativePath;
+		}
+	}
+}
+
+Result File::Copy(
+		const QString &source,
+		const QString &path,
+		Stats *stats) {
+	QFile f(source);
+	if (!f.exists() || !f.open(QIODevice::ReadOnly)) {
+		return Result(Result::Type::FatalError, source);
+	}
+	const auto bytes = f.readAll();
+	if (bytes.size() != f.size()) {
+		return Result(Result::Type::FatalError, source);
+	}
+	return File(path, stats).writeBlock(bytes);
+}
+
+} // namespace Output
+} // namespace File