[lua] Add a hook on standard fd activity

Signed-off-by: Julien Danjou <julien@danjou.info>

awesome.c

@@ -279,12 +279,15 @@ main(int argc, char **argv)
     char buf[1024];
     const char *confpath = NULL;
     int r, xfd, csfd, dbusfd, i, screen_nbr, opt;
-    ssize_t cmdlen = 1;
+    ssize_t len = 1;
     const xcb_query_extension_reply_t *shape_query, *randr_query;
     fd_set rd;
     xcb_generic_event_t *ev;
     struct sockaddr_un *addr;
     client_t *c;
+    int pstdout[2], pstderr[2], 
+        rstderr = -1, rstdout = -1,
+        a_stderr, a_stdout;
     static struct option long_options[] =
     {
         {"help",    0, NULL, 'h'},
@@ -298,15 +301,15 @@ main(int argc, char **argv)
 
     /* save argv */
     for(i = 0; i < argc; i++)
-        cmdlen += a_strlen(argv[i]) + 1;
+        len += a_strlen(argv[i]) + 1;
 
-    globalconf.argv = p_new(char, cmdlen);
-    a_strcpy(globalconf.argv, cmdlen, argv[0]);
+    globalconf.argv = p_new(char, len);
+    a_strcpy(globalconf.argv, len, argv[0]);
 
     for(i = 1; i < argc; i++)
     {
-        a_strcat(globalconf.argv, cmdlen, " ");
-        a_strcat(globalconf.argv, cmdlen, argv[i]);
+        a_strcat(globalconf.argv, len, " ");
+        a_strcat(globalconf.argv, len, argv[i]);
     }
 
     /* check args */
@@ -376,6 +379,33 @@ main(int argc, char **argv)
     atom_cache_list_init(&globalconf.atoms);
     ewmh_init_atoms();
 
+    /* grab stdout and stderr */
+    if(pipe(pstdout) == -1)
+    {
+        perror("unable to pipe");
+        a_stdout = -1;
+    }
+    else
+    {
+        rstdout = dup(fileno(stdout));
+        dup2(pstdout[1], fileno(stdout));
+        a_stdout = pstdout[0];
+        /* stop making stdout buffered */
+        setvbuf(stdout, NULL, _IONBF, 0);
+    }
+
+    if(pipe(pstderr) == -1)
+    {
+        perror("unable to pipe");
+        a_stderr = -1;
+    }
+    else
+    {
+        rstderr = dup(fileno(stderr));
+        dup2(pstderr[1], fileno(stderr));
+        a_stderr = pstderr[0];
+    }
+
     /* init screens struct */
     globalconf.screens_info = screensinfo_new(globalconf.connection);
     globalconf.screens = p_new(screen_t, globalconf.screens_info->nscreen);
@@ -486,15 +516,41 @@ main(int argc, char **argv)
             FD_SET(csfd, &rd);
         if(dbusfd >= 0)
             FD_SET(dbusfd, &rd);
+        if(a_stdout >= 0)
+            FD_SET(a_stdout, &rd);
+        if(a_stderr >= 0)
+            FD_SET(a_stderr, &rd);
         FD_SET(xfd, &rd);
-        if(select(MAX(MAX(xfd, csfd), dbusfd) + 1, &rd, NULL, NULL, NULL) == -1)
+
+        if(select(MAX(MAX(MAX(MAX(xfd, csfd), dbusfd), a_stdout), a_stderr) + 1,
+                  &rd, NULL, NULL, NULL) == -1)
         {
             if(errno == EINTR)
                 continue;
             eprint("select failed");
         }
+
+        /* Read and write stdout */
+        if(a_stdout >= 0 && FD_ISSET(a_stdout, &rd))
+        {
+            len = read(a_stdout, buf, sizeof(buf));
+            write(rstdout, buf, len);
+            /* call hook */
+            lua_pushlstring(globalconf.L, buf, len);
+            luaA_dofunction(globalconf.L, globalconf.hooks.fdactivity, 1);
+        }
+
+        if(a_stderr >= 0 && FD_ISSET(a_stderr, &rd))
+        {
+            len = read(a_stderr, buf, sizeof(buf));
+            write(rstderr, buf, len);
+            /* call hook */
+            lua_pushlstring(globalconf.L, buf, len);
+            luaA_dofunction(globalconf.L, globalconf.hooks.fdactivity, 1);
+        }
+
         if(csfd >= 0 && FD_ISSET(csfd, &rd))
-            switch(r = recv(csfd, buf, sizeof(buf)-1, MSG_TRUNC))
+            switch(r = recv(csfd, buf, sizeof(buf) - 1, MSG_TRUNC))
             {
               case -1:
                 warn("error reading UNIX domain socket: %s", strerror(errno));

awesomerc.lua.in

@@ -87,6 +87,16 @@ for s = 1, awesome.screen_count() do
     mystatusbar:widget_add(mylayoutbox[s])
     mystatusbar:add(s)
 end
+
+-- Create a textbox widget for debug messages on screen 1
+mydebugbox = widget.new({ type = "textbox", name = "mydebugbox", align = "left" })
+mydebugbox:set("text", "No debug information.")
+mydebugbar = statusbar.new({ position = "off", name = "mydebugbar",
+                            fg = "white", bg = "black" })
+mydebugbar:widget_add(mydebugbox)
+mydebugbar:add(1)
+awesome.key({ modkey }, "d", function () mydebugbar:position_set("bottom") end)
+awesome.key({ modkey, "Control" }, "d", function () mydebugbar:position_set("off") end)
 -- }}}
 
 -- {{{ Mouse bindings
@@ -208,12 +218,20 @@ function hook_arrange(screen)
     mylayoutbox[screen]:set("image", "@iconsdir@/layouts/" .. layout .. "w.png")
 end
 
+-- Hook function to print errors message
+-- WARNING: you should _NOT_ print anything in this function
+-- or you go into infinite loop
+function hook_fdactivity(text)
+    mydebugbox:set("text", "<span font_desc=\"fixed 10\">" .. text ..  "</span>")
+end
+
 -- Set up some hooks
 hooks.focus(hook_focus)
 hooks.unfocus(hook_unfocus)
 hooks.newclient(hook_newclient)
 hooks.mouseover(hook_mouseover)
 hooks.arrange(hook_arrange)
+hooks.fdactivity(hook_fdactivity)
 -- }}}
 
 -- Respect size hints

lua.c

@@ -359,6 +359,20 @@ luaA_hooks_titleupdate(lua_State *L)
     return 0;
 }
 
+/** Set the function called on standard file descriptor (stdout and stderr) activity.
+ * This function is called with the output buffer text as argument.
+ * \param A function to call on each standard file descriptor activity.
+ */
+static int
+luaA_hooks_fdactivity(lua_State *L)
+{
+    luaA_checkfunction(L, 1);
+    if(globalconf.hooks.fdactivity)
+        luaL_unref(L, LUA_REGISTRYINDEX, globalconf.hooks.fdactivity);
+    globalconf.hooks.fdactivity = luaL_ref(L, LUA_REGISTRYINDEX);
+    return 0;
+}
+
 /** Set default font.
  * \param A string with a font name in Pango format.
  */
@@ -434,6 +448,7 @@ luaA_parserc(const char *rcfile)
         { "mouseover", luaA_hooks_mouseover },
         { "arrange", luaA_hooks_arrange },
         { "titleupdate", luaA_hooks_titleupdate },
+        { "fdactivity", luaA_hooks_fdactivity },
         { NULL, NULL }
     };
 

statusbar.c

@@ -43,8 +43,6 @@ statusbar_draw(statusbar_t *statusbar)
     int left = 0, right = 0;
     area_t rectangle = { 0, 0, 0, 0, NULL, NULL };
 
-    statusbar->need_update.value = false;
-
     if(!statusbar->position)
         return;
 
@@ -99,6 +97,8 @@ statusbar_refresh(void *p)
             pthread_cond_wait(&statusbar->need_update.cond, &statusbar->need_update.lock);
 
         statusbar_draw(statusbar);
+        statusbar->need_update.value = false;
+
         pthread_mutex_unlock(&statusbar->need_update.lock);
     }
 

structs.h

@@ -429,6 +429,8 @@ struct awesome_t
         luaA_function arrange;
         /** Command to run on title change */
         luaA_function titleupdate;
+        /** Command to run on every standard output printing */
+        luaA_function fdactivity;
     } hooks;
 };