progs/miniglx/sample_server2.c

   1
   2 /*
   3  * Sample server that just keeps first available window mapped.
   4  *
   5  * It also reads and echos anything that happens on stdin as an
   6  * example of tracking events from sources other than miniglx clients.
   7  *
   8  * It reads & writes without blocking, so that eg. piping a lot of
   9  * text to stdin and then hitting 'ctrl-S' on the output stream won't
  10  * cause it to stop handling miniglx events.
  11  *
  12  * See select_tut in the linux manual pages for a good overview of the
  13  * select(2) system call.
  14  */
  15
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <string.h>
  21 #include <GL/gl.h>
  22 #include <GL/miniglx.h>
  23 #include <errno.h>
  24 #include <assert.h>
  25
  26 struct client {
  27    struct client *next;
  28    Window windowid;
  29    int mappable;
  30 };
  31
  32 struct client *clients = 0, *mapped_client = 0;
  33
  34 #define BUFSZ 4096
  35 char rbuf[BUFSZ];
  36 int rbuf_count;
  37
  38
  39 static struct client *find_client( Window id )
  40 {
  41    struct client *c;
  42
  43    for (c = clients ; c ; c = c->next)
  44       if (c->windowid == id)
  45          return c;
  46
  47    return 0;
  48 }
  49
  50 int main( int argc, char *argv[] )
  51 {
  52    Display *dpy;
  53    XEvent ev;
  54    int autostart = 0;
  55
  56    if (argc == 2 && strcmp(argv[1], "-autostart") == 0)
  57       autostart = 1;
  58
  59    dpy = __miniglx_StartServer(NULL);
  60    if (!dpy) {
  61       fprintf(stderr, "Error: __miniglx_StartServer failed\n");
  62       return 1;
  63    }
  64
  65    /* How is vt switching communicated through the XNextEvent interface?
  66     */
  67    while (1) {
  68       int r, n;
  69       struct timeval tv;
  70       fd_set rfds, wfds;
  71       int bored = 0;
  72
  73       FD_ZERO(&rfds);
  74       FD_ZERO(&wfds);
  75       tv.tv_sec = 1;
  76       tv.tv_usec = 0;
  77
  78       if (rbuf_count) {
  79          FD_SET( 1, &wfds );    /* notify when we can write out buffer */
  80          n = 1;
  81       }
  82       else {
  83          FD_SET( 0, &rfds );    /* else notify when new data to read */
  84          n = 0;
  85       }
  86
  87       /* __miniglx_Select waits until any of these file groups becomes
  88        * readable/writable/etc (like regular select), until timeout
  89        * expires (like regular select), until a signal is received
  90        * (like regular select) or until an event is available for
  91        * XCheckMaskEvent().
  92        */
  93       r = __miniglx_Select( dpy, n+1, &rfds, &wfds, 0, &tv );
  94
  95       /* This can happen if select() is interrupted by a signal:
  96        */
  97       if (r < 0 && errno != EINTR && errno != EAGAIN) {
  98          perror ("select()");
  99          exit (1);
 100       }
 101
 102       if (tv.tv_sec == 0 && tv.tv_usec == 0)
 103          bored = 1;
 104
 105       /* Check and handle events on our local file descriptors
 106        */
 107       if (FD_ISSET( 0, &rfds )) {
 108          /* Something on stdin */
 109          assert(rbuf_count == 0);
 110          r = read(0, rbuf, BUFSZ);
 111          if (r < 1) {
 112             perror("read");
 113             abort();
 114          }
 115          rbuf_count = r;
 116       }
 117
 118       if (FD_ISSET( 1, &wfds )) {
 119          /* Can write to stdout */
 120          assert(rbuf_count > 0);
 121          r = write(1, rbuf, rbuf_count);
 122          if (r < 1) {
 123             perror("write");
 124             abort();
 125          }
 126          rbuf_count -= r;
 127          if (rbuf_count)
 128             memmove(rbuf + r, rbuf, rbuf_count);
 129       }
 130
 131
 132       /* Check and handle events generated by miniglx:
 133        */
 134       while (XCheckMaskEvent( dpy, ~0, &ev )) {
 135          struct client *c;
 136          bored = 0;
 137
 138          fprintf(stderr, "Received event %d\n", ev.type);
 139
 140          switch (ev.type) {
 141          case CreateNotify:
 142             fprintf(stderr, "CreateNotify -- new client\n");
 143             c = malloc(sizeof(*c));
 144             c->next = clients;
 145             c->windowid = ev.xcreatewindow.window;
 146             c->mappable = False;
 147             clients = c;
 148             break;
 149
 150          case DestroyNotify:
 151             fprintf(stderr, "DestroyNotify\n");
 152             c = find_client(ev.xdestroywindow.window);
 153             if (!c) break;
 154             if (c == clients)
 155                clients = c->next;
 156             else {
 157                struct client *t;
 158                for (t = clients ; t->next != c ; t = t->next)
 159                   ;
 160                t->next = c->next;
 161             }
 162
 163             if (c == mapped_client)
 164                mapped_client = 0;
 165
 166             free(c);
 167             break;
 168
 169          case MapRequest:
 170             fprintf(stderr, "MapRequest\n");
 171             c = find_client(ev.xmaprequest.window);
 172             if (!c) break;
 173             c->mappable = True;
 174             break;
 175
 176          case UnmapNotify:
 177             fprintf(stderr, "UnmapNotify\n");
 178             c = find_client(ev.xunmap.window);
 179             if (!c) break;
 180             c->mappable = False;
 181             if (c == mapped_client)
 182                mapped_client = 0;
 183             break;
 184
 185          default:
 186             break;
 187          }
 188       }
 189
 190
 191       /* Search for first mappable client if none already mapped.
 192        */
 193       if (!mapped_client) {
 194          struct client *c;
 195          for (c = clients ; c ; c = c->next) {
 196             if (c->mappable) {
 197                XMapWindow( dpy, c->windowid );
 198                mapped_client = c;
 199                break;
 200             }
 201          }
 202          if (!clients && autostart) {
 203             system("nohup ./texline &");
 204             system("nohup ./manytex &");
 205          }
 206       }
 207       else if (bored) {
 208          struct client *c;
 209          /* bored of mapped client now, let's try & find another one */
 210          for (c = mapped_client->next ; c && !c->mappable ; c = c->next)
 211             ;
 212          if (!c)
 213             for (c = clients ; c && !c->mappable ; c = c->next)
 214                ;
 215          if (c && c != mapped_client) {
 216             XUnmapWindow( dpy, mapped_client->windowid );
 217             XMapWindow( dpy, c->windowid );
 218             mapped_client = c;
 219          }
 220          else
 221             fprintf(stderr, "I'm bored!\n");
 222       }
 223    }
 224
 225    XCloseDisplay( dpy );
 226
 227    return 0;
 228 }