add avutil.go

avutil/avutil.go

@@ -0,0 +1,174 @@
+package avutil
+
+import (
+	"io"
+	"fmt"
+	"bytes"
+	"github.com/nareix/av"
+	"net/url"
+	"os"
+	"path"
+)
+
+type handlerDemuxer struct {
+	av.Demuxer
+	r io.ReadCloser
+}
+
+func (self handlerDemuxer) Close() error {
+	return self.r.Close()
+}
+
+type handlerMuxer struct {
+	av.Muxer
+	w io.WriteCloser
+}
+
+func (self handlerMuxer) Close() error {
+	return self.w.Close()
+}
+
+type RegisterHandler struct {
+	Ext string
+	ReaderDemuxer func(io.Reader)av.Demuxer
+	WriterMuxer func(io.Writer)av.Muxer
+	UrlDemuxer func(string)(bool,av.DemuxerCloser,error)
+	UrlReader func(string)(bool,io.ReadCloser,error)
+	Probe func([]byte)bool
+}
+
+type Handlers struct {
+	handlers []RegisterHandler
+}
+
+func (self *Handlers) Add(fn func(*RegisterHandler)) {
+	handler := &RegisterHandler{}
+	fn(handler)
+	self.handlers = append(self.handlers, *handler)
+}
+
+func (self *Handlers) openUrl(u *url.URL, uri string) (r io.ReadCloser, err error) {
+	if u == nil {
+		r, err = os.Open(uri)
+		return
+	}
+	for _, handler := range self.handlers {
+		if handler.UrlReader != nil {
+			var ok bool
+			if ok, r, err = handler.UrlReader(uri); ok {
+				return
+			}
+		}
+	}
+	err = fmt.Errorf("avutil: openUrl %s failed", uri)
+	return
+}
+
+func (self *Handlers) createUrl(u *url.URL, uri string) (w io.WriteCloser, err error) {
+	w, err = os.Create(uri)
+	return
+}
+
+func (self *Handlers) Open(uri string) (demuxer av.DemuxerCloser, err error) {
+	for _, handler := range self.handlers {
+		if handler.UrlDemuxer != nil {
+			var ok bool
+			if ok, demuxer, err = handler.UrlDemuxer(uri); ok {
+				return
+			}
+		}
+	}
+
+	var r io.ReadCloser
+	var ext string
+	var u *url.URL
+	var uerr error
+	if u, uerr = url.Parse(uri); uerr != nil {
+		ext = path.Ext(uri)
+	} else {
+		ext = path.Ext(u.Path)
+	}
+
+	if ext != "" {
+		for _, handler := range self.handlers {
+			if handler.Ext == ext {
+				if handler.ReaderDemuxer != nil {
+					if r, err = self.openUrl(u, uri); err != nil {
+						return
+					}
+					demuxer = handlerDemuxer{
+						Demuxer: handler.ReaderDemuxer(r),
+						r: r,
+					}
+					return
+				}
+			}
+		}
+	}
+
+	var probebuf [1024]byte
+	if r, err = self.openUrl(u, uri); err != nil {
+		return
+	}
+	if _, err = io.ReadFull(r, probebuf[:]); err != nil {
+		return
+	}
+
+	for _, handler := range self.handlers {
+		if handler.Probe != nil && handler.Probe(probebuf[:]) && handler.ReaderDemuxer != nil {
+			demuxer = handlerDemuxer{
+				Demuxer: handler.ReaderDemuxer(io.MultiReader(bytes.NewReader(probebuf[:]), r)),
+				r: r,
+			}
+			return
+		}
+	}
+
+	err = fmt.Errorf("avutil: open %s failed", uri)
+	return
+}
+
+func (self *Handlers) Create(uri string) (muxer av.MuxerCloser, err error) {
+	var ext string
+	var u *url.URL
+	var uerr error
+	if u, uerr = url.Parse(uri); uerr != nil {
+		ext = path.Ext(uri)
+	} else {
+		ext = path.Ext(u.Path)
+	}
+
+	if ext != "" {
+		for _, handler := range self.handlers {
+			if handler.Ext == ext && handler.WriterMuxer != nil {
+				var w io.WriteCloser
+				if w, err = self.createUrl(u, uri); err != nil {
+					return
+				}
+				muxer = handlerMuxer{
+					Muxer: handler.WriterMuxer(w),
+					w: w,
+				}
+				return
+			}
+		}
+	}
+
+	err = fmt.Errorf("avutil: create %s failed", uri)
+	return
+}
+
+var defaultHandlers = &Handlers{}
+
+func AddHandler(fn func(*RegisterHandler)) {
+	defaultHandlers.Add(fn)
+}
+
+func Open(url string) (demuxer av.Demuxer, err error) {
+	return defaultHandlers.Open(url)
+}
+
+func Create(url string) (muxer av.Muxer, err error) {
+	return defaultHandlers.Create(url)
+}
+