X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=stdin.c;h=8b18c2e2cef6c54975cde07285fd68207334d63b;hp=d33be3588b9211c8efa4a98991c9a6bd1b1ce2ca;hb=82008b5367b438f01bb3899a93b406a6066d2b1f;hpb=704605b466aca3ae6ca6d1e03b6af55e3d245502;ds=sidebyside

diff --git a/stdin.c b/stdin.c
index d33be358..8b18c2e2 100644
--- a/stdin.c
+++ b/stdin.c
@@ -1,3 +1,23 @@
+/*
+ * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ *
+ *     This program is free software; you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation; either version 2 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program; if not, write to the Free Software
+ *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
+ */
+
+/** \file stdin.c functions that deal with reading from stdin */
+
 #include "para.h"
 #include "string.h"
 #include "list.h"
@@ -6,12 +26,25 @@
 #include "error.h"
 #include "stdin.h"
 
+/**
+ * the pre_select function of the stdin task
+ *
+ * \param s the scheduler this task was registered to
+ * \param t the task structure of the stdin task
+ *
+ * This function is always successful. If there is space left in the
+ * buffer of the stdin task, it adds \p STDIN_FILENO to the read fd set
+ * of \a s.
+ */
 void stdin_pre_select(struct sched *s, struct task *t)
 {
 	struct stdin_task *sit = t->private_data;
-	if (sit->loaded < sit->bufsize)
-		para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
-	t->ret = 1; /* success */
+	t->ret = 1;
+	sit->check_fd = 0;
+	if (sit->loaded >= sit->bufsize)
+		return;
+	sit->check_fd = 1;
+	para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
 }
 
 static void stdin_default_event_handler(struct task *t)
@@ -20,13 +53,24 @@ static void stdin_default_event_handler(struct task *t)
 	unregister_task(t);
 }
 
+/**
+ * the post select function of the stdin task
+ *
+ * \param s the scheduler this task was registered to
+ * \param t the task structure of the stdin task
+ *
+ * This function checks if \p STDIN_FILENO was included by in the read fd set
+ * of \a s during the previous pre_select call.  If yes, and \p STDIN_FILENO
+ * appeears to be readable, data is read from stdin into the buffer of the
+ * stdin task.
+ */
 void stdin_post_select(struct sched *s, struct task *t)
 {
 	struct stdin_task *sit = t->private_data;
 	ssize_t ret;
 
 	t->ret = 1;
-	if (sit->loaded >= sit->bufsize)
+	if (!sit->check_fd)
 		return;
 	if (!FD_ISSET(STDIN_FILENO, &s->rfds))
 		return;
@@ -42,6 +86,16 @@ void stdin_post_select(struct sched *s, struct task *t)
 		sit->eof = 1;
 }
 
+/**
+ * initialize a stdin task structure with default values
+ *
+ * \param sit the stdin task structure
+ *
+ * This fills in the pre/post select function poinzters of the task structure
+ * given by \a sot. It also sets up a default error handler which unregisters
+ * the task. Moreover, \a loaded and \a eof are set to zero and \a bufsize is
+ * initialized to 16 KB (but no buffer is allocated).
+ */
 void stdin_set_defaults(struct stdin_task *sit)
 {
 	sit->bufsize = 16 * 1024,
@@ -51,5 +105,6 @@ void stdin_set_defaults(struct stdin_task *sit)
 	sit->task.post_select = stdin_post_select;
 	sit->task.event_handler = stdin_default_event_handler;
 	sit->task.private_data = sit;
+	mark_fd_nonblock(STDIN_FILENO);
 	sprintf(sit->task.status, "stdin reader");
 }