71f0ed8b74
This eliminates some overhead, because the compiler doesn't need to consider these functions throwing.
145 lines
2.9 KiB
C++
145 lines
2.9 KiB
C++
/*
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* Copyright 2003-2017 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef MPD_FILE_OUTPUT_STREAM_HXX
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#define MPD_FILE_OUTPUT_STREAM_HXX
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#include "check.h"
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#include "OutputStream.hxx"
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#include "fs/AllocatedPath.hxx"
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#include "Compiler.h"
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#ifndef WIN32
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#include "system/FileDescriptor.hxx"
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#endif
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#include <assert.h>
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#include <stdint.h>
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#ifdef WIN32
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#include <windows.h>
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#endif
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class Path;
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class FileOutputStream final : public OutputStream {
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const AllocatedPath path;
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#ifdef WIN32
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HANDLE handle = INVALID_HANDLE_VALUE;
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#else
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FileDescriptor fd = FileDescriptor::Undefined();
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#endif
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#ifdef HAVE_LINKAT
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/**
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* Was O_TMPFILE used? If yes, then linkat() must be used to
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* create a link to this file.
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*/
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bool is_tmpfile = false;
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#endif
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public:
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enum class Mode : uint8_t {
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/**
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* Create a new file, or replace an existing file.
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* File contents may not be visible until Commit() has
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* been called.
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*/
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CREATE,
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/**
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* Like #CREATE, but no attempt is made to hide file
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* contents during the transaction (e.g. via O_TMPFILE
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* or a hidden temporary file).
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*/
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CREATE_VISIBLE,
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/**
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* Append to a file that already exists. If it does
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* not, an exception is thrown.
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*/
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APPEND_EXISTING,
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/**
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* Like #APPEND_EXISTING, but create the file if it
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* does not exist.
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*/
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APPEND_OR_CREATE,
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};
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private:
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Mode mode;
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public:
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explicit FileOutputStream(Path _path, Mode _mode=Mode::CREATE);
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~FileOutputStream() {
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if (IsDefined())
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Cancel();
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}
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public:
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Path GetPath() const {
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return path;
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}
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gcc_pure
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uint64_t Tell() const noexcept;
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/* virtual methods from class OutputStream */
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void Write(const void *data, size_t size) override;
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void Commit();
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void Cancel();
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private:
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void OpenCreate(bool visible);
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void OpenAppend(bool create);
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bool Close() {
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assert(IsDefined());
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#ifdef WIN32
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CloseHandle(handle);
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handle = INVALID_HANDLE_VALUE;
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return true;
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#else
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return fd.Close();
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#endif
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}
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#ifdef WIN32
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bool SeekEOF() {
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return SetFilePointer(handle, 0, nullptr,
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FILE_END) != 0xffffffff;
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}
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#endif
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bool IsDefined() const {
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#ifdef WIN32
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return handle != INVALID_HANDLE_VALUE;
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#else
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return fd.IsDefined();
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#endif
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}
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};
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#endif
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