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static void main_loop()//主要的循环，^_^
{
#ifdef SIGNAL_BLOCKING //阻塞信号
sigset_t newmask, oldmask;
sigemptyset(&newmask);
sigaddset(&newmask,SIGINT);
sigaddset(&newmask,SIGTERM);
sigaddset(&newmask,SIGUSR1);
#endif
#ifdef X11
Region region = XCreateRegion();//create a new empty region
#ifdef HAVE_XDAMAGE
int event_base, error_base;
if (!XDamageQueryExtension (display, &event_base, &error_base)) {
ERR("Xdamage extension unavailable");
}
Damage damage = XDamageCreate(display, window.window, XDamageReportNonEmpty);
XserverRegion region2 = XFixesCreateRegionFromWindow(display, window.window, 0);
XserverRegion part = XFixesCreateRegionFromWindow(display, window.window, 0);
#endif /* HAVE_XDAMAGE */
#endif /* X11 */
info.looped = 0;
while (total_run_times == 0 || info.looped < total_run_times) {
info.looped++;
#ifdef SIGNAL_BLOCKING
/* block signals. we will inspect for pending signals later *///首先阻塞信号，准备好以后再打开
if (sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0)
CRIT_ERR("unable to sigprocmask()");
#endif
#ifdef X11
XFlush(display);// flushes the output buffer
/* wait for X event or timeout */
if (!XPending(display)) {//display Specifies the connection to the X server
fd_set fdsr;
struct timeval tv;
int s;
double t =
update_interval - (get_time() -
last_update_time);
if (t < 0)
t = 0;
tv.tv_sec = (long) t;
tv.tv_usec = (long) (t * 1000000) % 1000000;
FD_ZERO(&fdsr);
FD_SET(ConnectionNumber(display), &fdsr);
s = select(ConnectionNumber(display) + 1, &fdsr, 0,
0, &tv);
#else
usleep(update_interval*1000000); /* FIXME just sleep for the interval time if no X11 */
#endif /* X11 */
#ifdef X11
if (s == -1) {
if (errno != EINTR)
ERR("can't select(): %s",
strerror(errno));
} else {
/* timeout */
if (s == 0)
#endif /* X11 */
update_text();//更新显示的文本
#ifdef X11
}
}
if (need_to_update) {
#ifdef OWN_WINDOW
int wx = window.x, wy = window.y;
#endif
need_to_update = 0;
selected_font = 0;
update_text_area();//更新文本显示区
#ifdef OWN_WINDOW
if (own_window) {
/* resize window if it isn't right size */
if (!fixed_size &&
(text_width + border_margin * 2 + 1 !=
window.width
|| text_height + border_margin * 2 + 1 !=
window.height)) {
window.width =
text_width +
border_margin * 2 + 1;
window.height =
text_height +
border_margin * 2 + 1;
XResizeWindow(display,
window.window,
window.width,
window.height);
if (own_window) {
set_transparent_background(window.window);
}
}
/* move window if it isn't in right position */
if (!fixed_pos
&& (window.x != wx
|| window.y != wy)) {
XMoveWindow(display, window.window,
window.x, window.y);
}
}
#endif
clear_text(1);
#ifdef HAVE_XDBE
if (use_xdbe) {
XRectangle r;
r.x = text_start_x - border_margin;
r.y = text_start_y - border_margin;
r.width = text_width + border_margin * 2;
r.height = text_height + border_margin * 2;
XUnionRectWithRegion(&r, region, region);
}
#endif
}
/* handle X events *///支持X的事件
while (XPending(display)) {
XEvent ev;
XNextEvent(display, &ev);
switch (ev.type) {
case Expose:
{
XRectangle r;
r.x = ev.xexpose.x;
r.y = ev.xexpose.y;
r.width = ev.xexpose.width;
r.height = ev.xexpose.height;
XUnionRectWithRegion(&r, region,
region);
}
break;
#ifdef OWN_WINDOW
case ReparentNotify:
/* set background to ParentRelative for all parents */
if (own_window) {
set_transparent_background(window.
window);
}
break;
case ConfigureNotify:
if (own_window) {
/* if window size isn't what expected, set fixed size */
if (ev.xconfigure.width !=
window.width
|| ev.xconfigure.height !=
window.height) {
if (window.width != 0
&& window.height != 0)
fixed_size = 1;
/* clear old stuff before screwing up size and pos */
clear_text(1);
{
XWindowAttributes
attrs;
if (XGetWindowAttributes(display, window.window, &attrs)) {
window.
width =
attrs.
width;
window.
height
=
attrs.
height;
}
}
text_width =
window.width -
border_margin * 2 - 1;
text_height =
window.height -
border_margin * 2 - 1;
if (text_width > maximum_width && maximum_width > 0)
text_width = maximum_width;
}
/* if position isn't what expected, set fixed pos, total_updates
* avoids setting fixed_pos when window is set to weird locations
* when started */
/*if (total_updates >= 2 this is broken
&& !fixed_pos
&& (window.x != ev.xconfigure.x
|| window.y !=
ev.xconfigure.y)
&& (ev.xconfigure.x != 0
|| ev.xconfigure.y != 0)) {
fixed_pos = 1;
}*/
set_font();
}
break;
case ButtonPress:
if (own_window)
{
/* forward the click to the desktop window */
XUngrabPointer(display, ev.xbutton.time);
ev.xbutton.window = window.desktop;
XSendEvent(display, ev.xbutton.window, False, ButtonPressMask, &ev);
}
break;
case ButtonRelease:
if (own_window)
{
/* forward the release to the desktop window */
ev.xbutton.window = window.desktop;
XSendEvent(display, ev.xbutton.window, False, ButtonReleaseMask, &ev);
}
break;
#endif
default:
#ifdef HAVE_XDAMAGE
if (ev.type == event_base + XDamageNotify) {
XDamageNotifyEvent *dev = (XDamageNotifyEvent *) &ev;
XFixesSetRegion(display, part, &dev->area, 1);
XFixesUnionRegion(display, region2, region2, part);
}
#endif /* HAVE_XDAMAGE */
break;
}
}
#ifdef HAVE_XDAMAGE
XDamageSubtract(display, damage, region2, None);
XFixesSetRegion(display, region2, 0, 0);
#endif /* HAVE_XDAMAGE */
/* XDBE doesn't seem to provide a way to clear the back buffer without
* interfering with the front buffer, other than passing XdbeBackground
* to XdbeSwapBuffers. That means that if we're using XDBE, we need to
* redraw the text even if it wasn't part of the exposed area. OTOH,
* if we're not going to call draw_stuff at all, then no swap happens
* and we can safely do nothing.
*/
if (!XEmptyRegion(region)) {
#ifdef HAVE_XDBE
if (use_xdbe) {
XRectangle r;
r.x = text_start_x - border_margin;
r.y = text_start_y - border_margin;
r.width = text_width + border_margin * 2;
r.height = text_height + border_margin * 2;
XUnionRectWithRegion(&r, region, region);//updates the destination region from a union of the specified rectangle and the specified source region.
}
#endif
XSetRegion(display, window.gc, region);//sets the clip-mask in the GC to the specified region
#ifdef XFT
if (use_xft) {
XftDrawSetClip(window.xftdraw, region);//X核心支持xft的显示
}
#endif
#endif /* X11 */
draw_stuff();
#ifdef X11
XDestroyRegion(region);
region = XCreateRegion();
}
#endif /* X11 */
#ifdef SIGNAL_BLOCKING
/* unblock signals of interest and let handler fly *///解除我们感兴趣信号的阻塞，由我们处理
if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0)
CRIT_ERR("unable to sigprocmask()");
#endif
switch(g_signal_pending) {
case SIGUSR1:
{
ERR("received SIGUSR1. reloading the config file.");
reload_config();//我们定义的一个重新加载config file的信号
break;
}
case SIGINT:
case SIGTERM:
{
ERR("received SIGINT or SIGTERM to terminate. bye!");
clean_up();
#ifdef X11
XDestroyRegion(region);
region = NULL;
#endif /* X11 */
return; /* return from main_loop */
/*break;*/
}
default:
{
/* Reaching here means someone set a signal( SIGXXXX, signal_handler )
* but didn't write any code to deal with it. if you don't want to
* handle a signal, don't set a handler on it in the first place. */
if (g_signal_pending)
ERR("ignoring signal (%d)", g_signal_pending);
break;
}
}
g_signal_pending=0;
}
#if defined(X11) && defined(HAVE_XDAMAGE)
XDamageDestroy(display, damage);
XFixesDestroyRegion(display, region2);
XFixesDestroyRegion(display, part);
XDestroyRegion(region);
region = NULL;
#endif /* X11 && HAVE_XDAMAGE */
}
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