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128 lines
3.0 KiB
C++
128 lines
3.0 KiB
C++
/*
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* \brief Interface for operations provided by file I/O service
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* \author Norman Feske
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* \author Emery Hemingway
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* \author Christian Helmuth
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* \date 2011-02-17
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*/
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/*
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* Copyright (C) 2011-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__VFS__FILE_IO_SERVICE_H_
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#define _INCLUDE__VFS__FILE_IO_SERVICE_H_
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#include <vfs/vfs_handle.h>
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namespace Vfs { struct File_io_service; }
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struct Vfs::File_io_service : Interface
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{
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/***********
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** Write **
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***********/
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enum Write_result { WRITE_ERR_WOULD_BLOCK, WRITE_ERR_INVALID,
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WRITE_ERR_IO, WRITE_OK };
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virtual Write_result write(Vfs_handle *vfs_handle,
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char const *buf, file_size buf_size,
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file_size &out_count) = 0;
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/**********
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** Read **
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**********/
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enum Read_result { READ_ERR_WOULD_BLOCK, READ_ERR_INVALID,
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READ_ERR_IO, READ_QUEUED,
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READ_OK };
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/**
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* Queue read operation
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*
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* \return false if queue is full
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*
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* If the queue is full, the caller can try again after a previous VFS
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* request is completed.
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*/
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virtual bool queue_read(Vfs_handle *, file_size)
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{
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return true;
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}
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virtual Read_result complete_read(Vfs_handle *, char * /* dst */,
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file_size /* in count */,
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file_size & /* out count */) = 0;
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/**
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* Return true if the handle has readable data
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*/
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virtual bool read_ready(Vfs_handle const &) const = 0;
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/**
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* Return true if the handle might accept a write operation
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*/
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virtual bool write_ready(Vfs_handle const &) const = 0;
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/**
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* Explicitly indicate interest in read-ready for a handle
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*
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* For example, the file-system-session plugin can then send READ_READY
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* packets to the server.
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*
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* \return false if notification setup failed
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*/
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virtual bool notify_read_ready(Vfs_handle *) { return true; }
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/***************
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** Ftruncate **
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***************/
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enum Ftruncate_result { FTRUNCATE_ERR_NO_PERM, FTRUNCATE_ERR_INTERRUPT,
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FTRUNCATE_ERR_NO_SPACE, FTRUNCATE_OK };
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virtual Ftruncate_result ftruncate(Vfs_handle *vfs_handle, file_size len) = 0;
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/**********
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** Sync **
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**********/
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enum Sync_result { SYNC_QUEUED, SYNC_ERR_INVALID, SYNC_OK };
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/**
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* Queue sync operation
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*
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* \return false if queue is full
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*
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* If the queue is full, the caller can try again after a previous VFS
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* request is completed.
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*/
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virtual bool queue_sync(Vfs_handle *) { return true; }
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virtual Sync_result complete_sync(Vfs_handle *) { return SYNC_OK; }
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/***********************
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** Modification time **
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***********************/
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/**
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* Update the modification time of a file
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*
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* \return true if update attempt was successful
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*/
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virtual bool update_modification_timestamp(Vfs_handle *, Vfs::Timestamp)
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{
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return true;
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}
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};
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#endif /* _INCLUDE__VFS__FILE_IO_SERVICE_H_ */
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