av/device/file/file.go

74 lines
1.9 KiB
Go

/*
DESCRIPTION
file.go provides an implementation of the AVDevice interface for media files.
AUTHORS
Saxon A. Nelson-Milton <saxon@ausocean.org>
LICENSE
Copyright (C) 2019 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package file
import (
"errors"
"fmt"
"io"
"os"
"bitbucket.org/ausocean/av/revid/config"
)
// AVFile is an implementation of the AVDevice interface for a file containg
// audio or video data.
type AVFile struct {
f io.ReadCloser
cfg config.Config
}
// NewAVFile returns a new AVFile.
func New() *AVFile { return &AVFile{} }
// Set simply sets the AVFile's config to the passed config.
func (m *AVFile) Set(c config.Config) error {
m.cfg = c
return nil
}
// Start will open the file at the location of the InputPath field of the
// config struct.
func (m *AVFile) Start() error {
var err error
m.f, err = os.Open(m.cfg.InputPath)
if err != nil {
return fmt.Errorf("could not open media file: %w", err)
}
return nil
}
// Stop will close the file such that any further reads will fail.
func (m *AVFile) Stop() error { return m.f.Close() }
// Read implements io.Reader. If start has not been called, or Start has been
// called and Stop has since been called, an error is returned.
func (m *AVFile) Read(p []byte) (int, error) {
if m.f != nil {
return m.f.Read(p)
}
return 0, errors.New("AV file is closed")
}