31ab78ae8e
InputStream::Read() and InputStream::Seek() are called with the mutex locked. That means the implementation must not block, or unlock the mutex before calling into blocking code. Previously, a slow CD drive could stall the whole MPD process, including the main thread, due to this problem. Closes #149
118 lines
2.8 KiB
C++
118 lines
2.8 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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#include "config.h" /* must be first for large file support */
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#include "FileInputPlugin.hxx"
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#include "../InputStream.hxx"
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#include "../InputPlugin.hxx"
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#include "fs/Path.hxx"
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#include "fs/FileInfo.hxx"
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#include "fs/io/FileReader.hxx"
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#include "system/FileDescriptor.hxx"
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#include "util/RuntimeError.hxx"
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#include <sys/stat.h>
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#include <fcntl.h>
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class FileInputStream final : public InputStream {
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FileReader reader;
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public:
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FileInputStream(const char *path, FileReader &&_reader, off_t _size,
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Mutex &_mutex, Cond &_cond)
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:InputStream(path, _mutex, _cond),
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reader(std::move(_reader)) {
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size = _size;
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seekable = true;
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SetReady();
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}
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/* virtual methods from InputStream */
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bool IsEOF() noexcept override {
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return GetOffset() >= GetSize();
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}
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size_t Read(void *ptr, size_t size) override;
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void Seek(offset_type offset) override;
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};
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InputStreamPtr
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OpenFileInputStream(Path path,
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Mutex &mutex, Cond &cond)
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{
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FileReader reader(path);
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const FileInfo info = reader.GetFileInfo();
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if (!info.IsRegular())
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throw FormatRuntimeError("Not a regular file: %s",
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path.c_str());
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#ifdef POSIX_FADV_SEQUENTIAL
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posix_fadvise(reader.GetFD().Get(), (off_t)0, info.GetSize(),
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POSIX_FADV_SEQUENTIAL);
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#endif
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return InputStreamPtr(new FileInputStream(path.ToUTF8().c_str(),
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std::move(reader), info.GetSize(),
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mutex, cond));
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}
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static InputStream *
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input_file_open(gcc_unused const char *filename,
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gcc_unused Mutex &mutex, gcc_unused Cond &cond)
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{
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/* dummy method; use OpenFileInputStream() instead */
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return nullptr;
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}
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void
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FileInputStream::Seek(offset_type new_offset)
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{
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{
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const ScopeUnlock unlock(mutex);
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reader.Seek((off_t)new_offset);
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}
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offset = new_offset;
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}
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size_t
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FileInputStream::Read(void *ptr, size_t read_size)
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{
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size_t nbytes;
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{
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const ScopeUnlock unlock(mutex);
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nbytes = reader.Read(ptr, read_size);
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}
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offset += nbytes;
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return nbytes;
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}
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const InputPlugin input_plugin_file = {
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"file",
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nullptr,
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nullptr,
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input_file_open,
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};
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