music.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	}
	chanprint(cs->ctl, "browsebot show");
	free(onum);
}

void
browsedown(char *onum)
{
	if(browsesp == 0){
		/* Make room for an entry by deleting the last */
		free(browsestack[Browsedepth-1].onum);
		memmove(browsestack + 1, browsestack, (Browsedepth-1) * sizeof(browsestack[0]));
		browsesp++;
	}
	/* Store current position in current stack frame */
	assert(browsesp > 0 && browsesp < Browsedepth);
	browsestack[browsesp].onum = strdup(parent.address);
	browsestack[browsesp].scrollpos = browseline;
	browsesp--;
	browseline = 0;
	if(browsestack[browsesp].onum && strcmp(browsestack[browsesp].onum, onum) == 0)
		browseline = browsestack[browsesp].scrollpos;
	browseto(onum, browseline);
}

void
browseup(char *onum)
{
	if(browsesp == Browsedepth){
		/* Make room for an entry by deleting the first */
		free(browsestack[0].onum);
		memmove(browsestack, browsestack + 1, browsesp * sizeof(browsestack[0]));
		browsesp--;
	}
	/* Store current position in current stack frame */
	assert(browsesp >= 0 && browsesp < Browsedepth);
	browsestack[browsesp].onum = strdup(parent.address);
	browsestack[browsesp].scrollpos = browseline;
	browsesp++;
	browseline = 0;
	if(browsestack[browsesp].onum && strcmp(browsestack[browsesp].onum, onum) == 0)
		browseline = browsestack[browsesp].scrollpos;
	browseto(onum, browseline);
}

void
addplaytext(char *s)
{
	chanprint(cs->ctl, "playtext accumulate %q", s);
}

void
work(void)
{
	static char *eventstr, *args[64], *s;
	static char buf[4096];
	int a, n, i;
	Alt alts[] = {
	[Exitbutton] =		{buts[Exitbutton].ctl->event, &eventstr, CHANRCV},
	[Pausebutton] =		{buts[Pausebutton].ctl->event, &eventstr, CHANRCV},
	[Playbutton] =		{buts[Playbutton].ctl->event, &eventstr, CHANRCV},
	[Stopbutton] =		{buts[Stopbutton].ctl->event, &eventstr, CHANRCV},
	[Prevbutton] =		{buts[Prevbutton].ctl->event, &eventstr, CHANRCV},
	[Nextbutton] =		{buts[Nextbutton].ctl->event, &eventstr, CHANRCV},
	[Rootbutton] =		{buts[Rootbutton].ctl->event, &eventstr, CHANRCV},
	[Deletebutton] =	{buts[Deletebutton].ctl->event, &eventstr, CHANRCV},
	[Helpbutton] =		{buts[Helpbutton].ctl->event, &eventstr, CHANRCV},
	[Volume] =		{vol->event, &eventstr, CHANRCV},
	[Browsetopwin] =	{browsetopwin->event, &eventstr, CHANRCV},
	[Browsebotwin] =	{browsebotwin->event, &eventstr, CHANRCV},
	[Browsebotscr] =	{browsebotscr->event, &eventstr, CHANRCV},
	[Playevent] =		{playevent, &eventstr, CHANRCV},
	[Playlistwin] =		{playlistwin->event, &eventstr, CHANRCV},
	[Nalt] =		{nil, nil, CHANEND}
	};

	activate(vol);
	activate(controlcalled("tabs"));
	activatebuttons(1 << Exitbutton | 1 << Rootbutton | 1 << Helpbutton);
	
	root = getroot();
	setparent(root);
	clearchildren();
	addparent("Root");
	chanprint(cs->ctl, "browsetop show");
	fillbrowsebot(root);
	chanprint(cs->ctl, "browsebot show");

	eventstr = nil;
	selected = -1;

	for(;;){
		a = alt(alts);
		if(debug & DBGCONTROL)
			fprint(2, "Event: %s\n", eventstr);
		n = tokenize(eventstr, args, nelem(args));
		switch(a){
		default:
			sysfatal("Illegal event %d in work", a);
		case Volume:
			if(n != 3 || strcmp(args[0], "volume") || strcmp(args[1], "volume"))
				sysfatal("Bad Volume event[%d]: %s %s", n, args[0], args[1]);
			setvolume(args[2]);
			break;
		case Exitbutton:
			return;
		case Pausebutton:
			if(n != 3 || strcmp(args[0], "pause:") || strcmp(args[1], "value"))
				sysfatal("Bad Pausebutton event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[2], "0") == 0)
				fprint(playctlfd, "resume");
			else
				fprint(playctlfd, "pause");
			break;
		case Playbutton:
			if(n != 3 || strcmp(args[0], "play:") || strcmp(args[1], "value"))
				sysfatal("Bad Playbutton event[%d]: %s %s", n, args[0], args[1]);
			if(playlist.selected >= 0){
				fprint(playctlfd, "play %d", playlist.selected);
			}else
				fprint(playctlfd, "play");
			break;
		case Stopbutton:
			if(n != 3 || strcmp(args[0], "stop:") || strcmp(args[1], "value"))
				sysfatal("Bad Stopbutton event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[2], "0") == 0)
				chanprint(cs->ctl, "%q value 1", buts[Stopbutton].ctl->name);
			fprint(playctlfd, "stop");
			break;
		case Prevbutton:
			if(n != 3 || strcmp(args[0], "prev:") || strcmp(args[1], "value"))
				sysfatal("Bad Prevbutton event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[2], "0") == 0)
				break;
			chanprint(cs->ctl, "%q value 0", buts[Prevbutton].ctl->name);
			fprint(playctlfd, "skip -1");
			break;
		case Nextbutton:
			if(n != 3 || strcmp(args[0], "next:") || strcmp(args[1], "value"))
				sysfatal("Bad Nextbutton event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[2], "0") == 0)
				break;
			chanprint(cs->ctl, "%q value 0", buts[Nextbutton].ctl->name);
			fprint(playctlfd, "skip 1");
			break;
		case Playlistwin:
			if(debug & (DBGCONTROL|DBGPLAY))
				fprint(2, "Playlistevent: %s %s\n", args[0], args[1]);
			if(n != 4 || strcmp(args[0], "playlistwin:") || strcmp(args[1], "select"))
				sysfatal("Bad Playlistwin event[%d]: %s %s", n, args[0], args[1]);
			n = atoi(args[2]);
			if(n < 0 || n >= playlist.nentries)
				sysfatal("Selecting line %d of %d", n, playlist.nentries);
			if(playlist.selected >= 0 && playlist.selected < playlist.nentries){
				chanprint(cs->ctl, "playlistwin select %d 0", playlist.selected);
				chanprint(cs->ctl, "playlistwin show");
			}
			playlist.selected = -1;
			deactivatebuttons(1<<Playbutton);
			if(strcmp(args[3], "1") == 0)
				playlistselect(n);
			break;
		case Rootbutton:
			chanprint(cs->ctl, "%q value 0", buts[Rootbutton].ctl->name);
			setparent(root);
			clearchildren();
			addparent("Root");
			chanprint(cs->ctl, "browsetop show");
			fillbrowsebot(root);
			chanprint(cs->ctl, "browsebot show");
			break;
		case Deletebutton:
			if(n != 3 || strcmp(args[0], "trash:") || strcmp(args[1], "value"))
				sysfatal("Bad Deletebutton event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[2], "0") == 0)
				break;
			chanprint(cs->ctl, "%q value 0", buts[Deletebutton].ctl->name);
			sendplaylist(nil, nil);
			break;
		case Helpbutton:
			chanprint(cs->ctl, "%q value 0", buts[Helpbutton].ctl->name);
			if(errorlines > 0){
				chanprint(cs->ctl, "errortext clear");
				chanprint(cs->ctl, "errortext topline 0");
				chanprint(cs->ctl, "errorscr max 0");
				chanprint(cs->ctl, "errorscr value 0");
			}
			if(errorlines >= 0){
				for(i = 0; helptext[i]; i++)
					chanprint(cs->ctl, "errortext accumulate %q", helptext[i]);
				chanprint(cs->ctl, "errorscr max %d", i);
			}
			chanprint(cs->ctl, "errortext topline 0");
			chanprint(cs->ctl, "errorscr value 0");
			errorlines = -1;
			chanprint(cs->ctl, "tabs value %d", WinError);
			break;
		case Browsetopwin:
			if(n != 4 || strcmp(args[0], "browsetopwin:") || strcmp(args[1], "select"))
				sysfatal("Bad Browsetopwin event[%d]: %s %s", n, args[0], args[1]);
			if(strcmp(args[3], "0") == 0)
				break;
			chanprint(cs->ctl, "browsetopwin select %s 0", args[2]);
			selected = -1;
			if(strcmp(args[3], "2") == 0)
				doplay(parent.address);
			else if(strcmp(args[3], "4") == 0){
				s = getparent(parent.address);
				browsedown(s);
			}
			break;
		case Browsebotwin:
			if(n != 4 || strcmp(args[0], "browsebotwin:") || strcmp(args[1], "select"))
				sysfatal("Bad Browsebotwin event[%d]: %s %s", n, args[0], args[1]);
			n = atoi(args[2]);
			if(n < 0 || n >= nchildren)
				sysfatal("Selection out of range: %d [%d]", n, nchildren);
			if(strcmp(args[3], "0") == 0){
				selected = -1;
				break;
			}
			if(n < 0)
				break;
			chanprint(cs->ctl, "browsebotwin select %d 0", n);
			selected = n;
			if(selected >= nchildren)
				sysfatal("Select out of range: %d [0⋯%d)", selected, nchildren);
			if(strcmp(args[3], "1") == 0){
				browseup(children[selected].address);
			}else if(strcmp(args[3], "2") == 0)
				doplay(children[selected].address);
			else if(strcmp(args[3], "4") == 0)
				browsedown(getparent(parent.address));
			break;
		case Browsebotscr:
			browseline = atoi(args[2]);
			chanprint(cs->ctl, "browsebotwin topline %d", browseline);
			break;
		case Playevent:
			if(n < 3 || strcmp(args[0], "playctlproc:"))
				sysfatal("Bad Playevent event[%d]: %s", n, args[0]);
			if(debug & (DBGCONTROL|DBGPLAY))
				fprint(2, "Playevent: %s %s\n", args[1], args[2]);
			if(strcmp(args[1], "error") ==0){
				if(n != 4){
					fprint(2, "Playevent: %s: arg count: %d\n", args[1], n);
					break;
				}
				if(errorlines < 0){
					chanprint(cs->ctl, "errortext clear");
					chanprint(cs->ctl, "errortext topline 0");
					chanprint(cs->ctl, "errorscr max 0");
					chanprint(cs->ctl, "errorscr value 0");
					errorlines = 0;
				}
				n = errorlines;
				chanprint(cs->ctl, "errortext accumulate %q", args[3]);
				chanprint(cs->ctl, "errorscr max %d", ++errorlines);
				if(n >= 0 && n <= errorlines - Dy(errortext->rect)/romanfont->height)
					n--;
				else
					n = errorlines - Dy(errortext->rect)/romanfont->height + 1;
				if(n < 0) n = 0;
				if(n < errorlines){
					chanprint(cs->ctl, "errortext topline %d",  n);
					chanprint(cs->ctl, "errorscr value %d",  n);
				}
				chanprint(cs->ctl, "tabs value %d", WinError);
			}else if(strcmp(args[1], "play") ==0){
				chanprint(cs->ctl, "%q value 1", buts[Playbutton].ctl->name);
				chanprint(cs->ctl, "%q value 0", buts[Stopbutton].ctl->name);
				chanprint(cs->ctl, "%q value 0", buts[Pausebutton].ctl->name);
				playlistselect(strtoul(args[2], nil, 0));
				chanprint(cs->ctl, "playtext clear");
				chanprint(cs->ctl, "playtext topline 0");
				chanprint(cs->ctl, "playscr max 0");
				chanprint(cs->ctl, "playscr value 0");
				playstate = Playing;
				activatebuttons(playingbuts);
				qlock(&playlist);
				if(playlist.selected < playlist.nentries){
					fillplaytext(playlist.entry[playlist.selected].onum);
					chanprint(cs->ctl, "playscr max %d", n);
				}
				qunlock(&playlist);
				chanprint(cs->ctl, "playwin show");
			}else if(strcmp(args[1], "stop") ==0){
				chanprint(cs->ctl, "%q value 0", buts[Playbutton].ctl->name);
				chanprint(cs->ctl, "%q value 1", buts[Stopbutton].ctl->name);
				chanprint(cs->ctl, "%q value 0", buts[Pausebutton].ctl->name);
				playlistselect(strtoul(args[2], nil, 0));
				chanprint(cs->ctl, "%q show", tabs[WinPlaylist].winname);
				playstate = PlayIdle;
				deactivatebuttons(playingbuts);
			}else if(strcmp(args[1], "pause") ==0){
				activatebuttons(playingbuts);
				chanprint(cs->ctl, "%q value 1", buts[Playbutton].ctl->name);
				chanprint(cs->ctl, "%q value 0", buts[Stopbutton].ctl->name);
				if(playstate == PlayPause){
					chanprint(cs->ctl, "%q value 0", buts[Pausebutton].ctl->name);
					playstate = Playing;
				}else{
					chanprint(cs->ctl, "%q value 1", buts[Pausebutton].ctl->name);
					playstate = PlayPause;
				}
			}else if(strcmp(args[1], "exits") ==0){
				threadexits("exitevent");
			}else{
				fprint(2, "Unknown play event:");
				for(i=0; i<n; i++)
					fprint(2, " %s", args[i]);
				fprint(2, "\n");
			}
			break;
		}
		if(eventstr){
			free(eventstr);
			eventstr = nil;
		}
	}
}

void
threadmain(int argc, char *argv[]){
	int wflag;

	wflag = 0;
	ARGBEGIN{
	case 'd':
		debug = strtol(ARGF(), nil, 0);
		break;
	case 't':
		tflag = 1;
		break;
	case 'w':
		wflag = 1;
		break;
	default:
		sysfatal(usage, argv0);
	}ARGEND

	quotefmtinstall();

	if(tflag)
		makewindow(320, 320, wflag);
	else
		makewindow(480, 480, wflag);

	playlist.selected = -1;

	playctlfd = open(playctlfile, OWRITE);
	if(playctlfd < 0)
		sysfatal("%s: %r", playctlfile);
	proccreate(playlistproc, nil, 8192);
	playevent = chancreate(sizeof(char *), 1);
	proccreate(playctlproc, playevent, 8192);
	proccreate(playvolproc, cs->ctl, 8192);

	work();

	closecontrolset(cs);
	threadexitsall(nil);
}