From 2b248ef7830b7f3e0bb0b801b69153ba177fa310 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 8 Aug 2022 23:57:01 +0900
Subject: [PATCH] audio: refactoring: remove audio/internal/cbackend

---
 audio/context_cbackend.go          |  30 +-
 audio/internal/cbackend/context.go |  67 -----
 audio/internal/cbackend/player.go  | 435 -----------------------------
 go.mod                             |   2 +-
 go.sum                             |   4 +-
 5 files changed, 28 insertions(+), 510 deletions(-)
 delete mode 100644 audio/internal/cbackend/context.go
 delete mode 100644 audio/internal/cbackend/player.go

diff --git a/audio/context_cbackend.go b/audio/context_cbackend.go
index e05274166..7b1442f60 100644
--- a/audio/context_cbackend.go
+++ b/audio/context_cbackend.go
@@ -20,20 +20,40 @@ package audio
 import (
 	"io"
 
-	"github.com/hajimehoshi/ebiten/v2/audio/internal/cbackend"
+	"github.com/hajimehoshi/oto/v2/mux"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/cbackend"
 )
 
 func newContext(sampleRate, channelCount, bitDepthInBytes int) (context, chan struct{}, error) {
-	ctx, ready, err := cbackend.NewContext(sampleRate, channelCount, bitDepthInBytes)
-	return &contextProxy{ctx}, ready, err
+	ready := make(chan struct{})
+	close(ready)
+
+	c := &contextProxy{mux.New(sampleRate, channelCount, bitDepthInBytes)}
+	cbackend.OpenAudio(sampleRate, channelCount, c.mux.ReadFloat32s)
+	return c, ready, nil
 }
 
 // contextProxy is a proxy between cbackend.Context and context.
 type contextProxy struct {
-	*cbackend.Context
+	mux *mux.Mux
 }
 
 // NewPlayer implements context.
 func (c *contextProxy) NewPlayer(r io.Reader) player {
-	return c.Context.NewPlayer(r)
+	return c.mux.NewPlayer(r)
+}
+
+func (c *contextProxy) Suspend() error {
+	// Do nothing so far.
+	return nil
+}
+
+func (c *contextProxy) Resume() error {
+	// Do nothing so far.
+	return nil
+}
+
+func (c *contextProxy) Err() error {
+	return nil
 }
diff --git a/audio/internal/cbackend/context.go b/audio/internal/cbackend/context.go
deleted file mode 100644
index c0cb780b3..000000000
--- a/audio/internal/cbackend/context.go
+++ /dev/null
@@ -1,67 +0,0 @@
-// Copyright 2021 The Ebiten Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build ebitenginecbackend || ebitencbackend
-// +build ebitenginecbackend ebitencbackend
-
-package cbackend
-
-import (
-	"io"
-
-	"github.com/hajimehoshi/ebiten/v2/internal/cbackend"
-)
-
-type Context struct {
-	sampleRate      int
-	channelCount    int
-	bitDepthInBytes int
-
-	players *players
-}
-
-func NewContext(sampleRate, channelCount, bitDepthInBytes int) (*Context, chan struct{}, error) {
-	c := &Context{
-		sampleRate:      sampleRate,
-		channelCount:    channelCount,
-		bitDepthInBytes: bitDepthInBytes,
-		players:         newPlayers(),
-	}
-	cbackend.OpenAudio(sampleRate, channelCount, c.players.read)
-	ready := make(chan struct{})
-	close(ready)
-	return c, ready, nil
-}
-
-func (c *Context) NewPlayer(src io.Reader) *Player {
-	return newPlayer(c, src)
-}
-
-func (c *Context) Suspend() error {
-	// Do nothing so far.
-	return nil
-}
-
-func (c *Context) Resume() error {
-	// Do nothing so far.
-	return nil
-}
-
-func (c *Context) Err() error {
-	return nil
-}
-
-func (c *Context) defaultBufferSize() int {
-	return c.sampleRate * c.channelCount * c.bitDepthInBytes / 2 // 0.5[s]
-}
diff --git a/audio/internal/cbackend/player.go b/audio/internal/cbackend/player.go
deleted file mode 100644
index 1e31a4ed5..000000000
--- a/audio/internal/cbackend/player.go
+++ /dev/null
@@ -1,435 +0,0 @@
-// Copyright 2021 The Ebiten Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build ebitenginecbackend || ebitencbackend
-// +build ebitenginecbackend ebitencbackend
-
-// TODO: This implementation is very similar to github.com/hajimehoshi/oto/v2's player.go
-// Unify them if possible.
-
-package cbackend
-
-import (
-	"errors"
-	"io"
-	"runtime"
-	"sync"
-)
-
-type playerState int
-
-const (
-	playerPaused playerState = iota
-	playerPlay
-	playerClosed
-)
-
-type players struct {
-	players map[*playerImpl]struct{}
-	buf     []float32
-	cond    *sync.Cond
-}
-
-func newPlayers() *players {
-	p := &players{
-		cond: sync.NewCond(&sync.Mutex{}),
-	}
-	go p.loop()
-	return p
-}
-
-func (ps *players) shouldWait() bool {
-	for p := range ps.players {
-		if p.canReadSourceToBuffer() {
-			return false
-		}
-	}
-	return true
-}
-
-func (ps *players) wait() {
-	ps.cond.L.Lock()
-	defer ps.cond.L.Unlock()
-
-	for ps.shouldWait() {
-		ps.cond.Wait()
-	}
-}
-
-func (ps *players) loop() {
-	var players []*playerImpl
-	for {
-		ps.wait()
-
-		ps.cond.L.Lock()
-		players = players[:0]
-		for p := range ps.players {
-			players = append(players, p)
-		}
-		ps.cond.L.Unlock()
-
-		for _, p := range players {
-			p.readSourceToBuffer()
-		}
-	}
-}
-
-func (ps *players) addPlayer(player *playerImpl) {
-	ps.cond.L.Lock()
-	defer ps.cond.L.Unlock()
-
-	if ps.players == nil {
-		ps.players = map[*playerImpl]struct{}{}
-	}
-	ps.players[player] = struct{}{}
-	ps.cond.Signal()
-}
-
-func (ps *players) removePlayer(player *playerImpl) {
-	ps.cond.L.Lock()
-	defer ps.cond.L.Unlock()
-
-	delete(ps.players, player)
-	ps.cond.Signal()
-}
-
-func (ps *players) read(buf []float32) {
-	ps.cond.L.Lock()
-	players := make([]*playerImpl, 0, len(ps.players))
-	for p := range ps.players {
-		players = append(players, p)
-	}
-	ps.cond.L.Unlock()
-
-	for i := range buf {
-		buf[i] = 0
-	}
-	for _, p := range players {
-		p.readBufferAndAdd(buf)
-	}
-	ps.cond.Signal()
-}
-
-type Player struct {
-	p *playerImpl
-}
-
-type playerImpl struct {
-	context    *Context
-	src        io.Reader
-	volume     float64
-	err        error
-	state      playerState
-	tmpbuf     []byte
-	buf        []byte
-	eof        bool
-	bufferSize int
-
-	m sync.Mutex
-}
-
-func newPlayer(context *Context, src io.Reader) *Player {
-	p := &Player{
-		p: &playerImpl{
-			context:    context,
-			src:        src,
-			volume:     1,
-			bufferSize: context.defaultBufferSize(),
-		},
-	}
-	runtime.SetFinalizer(p, (*Player).Close)
-	return p
-}
-
-func (p *Player) Err() error {
-	return p.p.Err()
-}
-
-func (p *playerImpl) Err() error {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	return p.err
-}
-
-func (p *Player) Play() {
-	p.p.Play()
-}
-
-func (p *playerImpl) Play() {
-	ch := make(chan struct{})
-	go func() {
-		p.m.Lock()
-		defer p.m.Unlock()
-
-		close(ch)
-		p.playImpl()
-	}()
-	<-ch
-}
-
-func (p *Player) SetBufferSize(bufferSize int) {
-	p.p.setBufferSize(bufferSize)
-}
-
-func (p *playerImpl) setBufferSize(bufferSize int) {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	orig := p.bufferSize
-	p.bufferSize = bufferSize
-	if bufferSize == 0 {
-		p.bufferSize = p.context.defaultBufferSize()
-	}
-	if orig != p.bufferSize {
-		p.tmpbuf = nil
-	}
-}
-
-func (p *playerImpl) ensureTmpBuf() []byte {
-	if p.tmpbuf == nil {
-		p.tmpbuf = make([]byte, p.bufferSize)
-	}
-	return p.tmpbuf
-}
-
-func (p *playerImpl) playImpl() {
-	if p.err != nil {
-		return
-	}
-	if p.state != playerPaused {
-		return
-	}
-
-	if !p.eof {
-		buf := p.ensureTmpBuf()
-		for len(p.buf) < p.bufferSize {
-			n, err := p.src.Read(buf)
-			if err != nil && err != io.EOF {
-				p.setErrorImpl(err)
-				return
-			}
-			p.buf = append(p.buf, buf[:n]...)
-			if err == io.EOF {
-				p.eof = true
-				break
-			}
-		}
-	}
-
-	if !p.eof || len(p.buf) > 0 {
-		p.state = playerPlay
-	}
-
-	p.m.Unlock()
-	p.context.players.addPlayer(p)
-	p.m.Lock()
-}
-
-func (p *Player) Pause() {
-	p.p.Pause()
-}
-
-func (p *playerImpl) Pause() {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	if p.state != playerPlay {
-		return
-	}
-	p.state = playerPaused
-}
-
-func (p *Player) Seek(offset int64, whence int) (int64, error) {
-	return p.p.Seek(offset, whence)
-}
-
-func (p *playerImpl) Seek(offset int64, whence int) (int64, error) {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	// If a player is playing, keep playing even after this seeking.
-	if p.state == playerPlay {
-		defer p.playImpl()
-	}
-
-	// Reset the internal buffer.
-	p.resetImpl()
-
-	// Check if the source implements io.Seeker.
-	s, ok := p.src.(io.Seeker)
-	if !ok {
-		return 0, errors.New("cbackend: the source must implement io.Seeker")
-	}
-	return s.Seek(offset, whence)
-}
-
-func (p *playerImpl) resetImpl() {
-	if p.state == playerClosed {
-		return
-	}
-	p.state = playerPaused
-	p.buf = p.buf[:0]
-	p.eof = false
-}
-
-func (p *Player) IsPlaying() bool {
-	return p.p.IsPlaying()
-}
-
-func (p *playerImpl) IsPlaying() bool {
-	p.m.Lock()
-	defer p.m.Unlock()
-	return p.state == playerPlay
-}
-
-func (p *Player) Volume() float64 {
-	return p.p.Volume()
-}
-
-func (p *playerImpl) Volume() float64 {
-	p.m.Lock()
-	defer p.m.Unlock()
-	return p.volume
-}
-
-func (p *Player) SetVolume(volume float64) {
-	p.p.SetVolume(volume)
-}
-
-func (p *playerImpl) SetVolume(volume float64) {
-	p.m.Lock()
-	defer p.m.Unlock()
-	p.volume = volume
-}
-
-func (p *Player) UnplayedBufferSize() int {
-	return p.p.UnplayedBufferSize()
-}
-
-func (p *playerImpl) UnplayedBufferSize() int {
-	p.m.Lock()
-	defer p.m.Unlock()
-	return len(p.buf)
-}
-
-func (p *Player) Close() error {
-	runtime.SetFinalizer(p, nil)
-	return p.p.Close()
-}
-
-func (p *playerImpl) Close() error {
-	p.m.Lock()
-	defer p.m.Unlock()
-	return p.closeImpl()
-}
-
-func (p *playerImpl) closeImpl() error {
-	p.m.Unlock()
-	p.context.players.removePlayer(p)
-	p.m.Lock()
-
-	if p.state == playerClosed {
-		return p.err
-	}
-	p.state = playerClosed
-	p.buf = nil
-	return p.err
-}
-
-func (p *playerImpl) readBufferAndAdd(buf []float32) int {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	if p.state != playerPlay {
-		return 0
-	}
-
-	bitDepthInBytes := p.context.bitDepthInBytes
-	n := len(p.buf) / bitDepthInBytes
-	if n > len(buf) {
-		n = len(buf)
-	}
-	volume := float32(p.volume)
-	src := p.buf[:n*bitDepthInBytes]
-
-	for i := 0; i < n; i++ {
-		var v float32
-		switch bitDepthInBytes {
-		case 1:
-			v8 := src[i]
-			v = float32(v8-(1<<7)) / (1 << 7)
-		case 2:
-			v16 := int16(src[2*i]) | (int16(src[2*i+1]) << 8)
-			v = float32(v16) / (1 << 15)
-		}
-		buf[i] += v * volume
-	}
-
-	copy(p.buf, p.buf[n*bitDepthInBytes:])
-	p.buf = p.buf[:len(p.buf)-n*bitDepthInBytes]
-
-	if p.eof && len(p.buf) == 0 {
-		p.state = playerPaused
-	}
-
-	return n
-}
-
-func (p *playerImpl) canReadSourceToBuffer() bool {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	if p.eof {
-		return false
-	}
-	return len(p.buf) < p.bufferSize
-}
-
-func (p *playerImpl) readSourceToBuffer() {
-	p.m.Lock()
-	defer p.m.Unlock()
-
-	if p.err != nil {
-		return
-	}
-	if p.state == playerClosed {
-		return
-	}
-
-	if len(p.buf) >= p.bufferSize {
-		return
-	}
-
-	buf := p.ensureTmpBuf()
-	n, err := p.src.Read(buf)
-
-	if err != nil && err != io.EOF {
-		p.setErrorImpl(err)
-		return
-	}
-
-	p.buf = append(p.buf, buf[:n]...)
-	if err == io.EOF {
-		p.eof = true
-		if len(p.buf) == 0 {
-			p.state = playerPaused
-		}
-	}
-}
-
-func (p *playerImpl) setErrorImpl(err error) {
-	p.err = err
-	p.closeImpl()
-}
diff --git a/go.mod b/go.mod
index b2f123dc5..2ac5f0ae8 100644
--- a/go.mod
+++ b/go.mod
@@ -8,7 +8,7 @@ require (
 	github.com/hajimehoshi/bitmapfont/v2 v2.2.1
 	github.com/hajimehoshi/file2byteslice v0.0.0-20210813153925-5340248a8f41
 	github.com/hajimehoshi/go-mp3 v0.3.3
-	github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220802151442-4f655ffe7bb4
+	github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220808142854-0d70fdd8205d
 	github.com/jakecoffman/cp v1.2.1
 	github.com/jezek/xgb v1.0.1
 	github.com/jfreymuth/oggvorbis v1.0.3
diff --git a/go.sum b/go.sum
index ff0dffe25..013b97a5e 100644
--- a/go.sum
+++ b/go.sum
@@ -11,8 +11,8 @@ github.com/hajimehoshi/go-mp3 v0.3.3 h1:cWnfRdpye2m9ElSoVqneYRcpt/l3ijttgjMeQh+r
 github.com/hajimehoshi/go-mp3 v0.3.3/go.mod h1:qMJj/CSDxx6CGHiZeCgbiq2DSUkbK0UbtXShQcnfyMM=
 github.com/hajimehoshi/oto v0.6.1 h1:7cJz/zRQV4aJvMSSRqzN2TImoVVMpE0BCY4nrNJaDOM=
 github.com/hajimehoshi/oto v0.6.1/go.mod h1:0QXGEkbuJRohbJaxr7ZQSxnju7hEhseiPx2hrh6raOI=
-github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220802151442-4f655ffe7bb4 h1:tykbQMVvjFgSvX5ndg05alWI0mfD7rm/DtysW9Z757U=
-github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220802151442-4f655ffe7bb4/go.mod h1:ZH5KyijkM53TgspdS9sArUe7vv9EP7x4aNYJAmfGhvE=
+github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220808142854-0d70fdd8205d h1:T64feTPB+qGhPnLRsyzlYNiz+jTd/pcPCqB8/VTgooY=
+github.com/hajimehoshi/oto/v2 v2.3.0-alpha.6.0.20220808142854-0d70fdd8205d/go.mod h1:ZH5KyijkM53TgspdS9sArUe7vv9EP7x4aNYJAmfGhvE=
 github.com/jakecoffman/cp v1.2.1 h1:zkhc2Gpo9l4NLUZfeG3j33+3bQD7MkqPa+n5PdX+5mI=
 github.com/jakecoffman/cp v1.2.1/go.mod h1:JjY/Fp6d8E1CHnu74gWNnU0+b9VzEdUVPoJxg2PsTQg=
 github.com/jezek/xgb v1.0.1 h1:YUGhxps0aR7J2Xplbs23OHnV1mWaxFVcOl9b+1RQkt8=