Add autoreload support by inotify (and dummy backend nop)

1 files changed, 154 insertions, 0 deletions

diff --git a/autoreload_inotify.c b/autoreload_inotify.c
new file mode 100644
index 0000000..4a8e455
--- /dev/null
+++ b/autoreload_inotify.c
@@ -0,0 +1,154 @@
+/* Copyright 2017 Max Voit
+ *
+ * This file is part of sxiv.
+ *
+ * sxiv 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.
+ *
+ * sxiv 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 sxiv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/inotify.h>
+#include <libgen.h>
+#include <time.h>
+
+#include "util.h"
+#include "autoreload.h"
+
+const struct timespec ten_ms = {0, 10000000};
+
+void arl_cleanup(void)
+{
+	if (autoreload.fd != -1 && autoreload.wd != -1)
+	{
+		if(inotify_rm_watch(autoreload.fd, autoreload.wd))
+			error(0, 0, "Failed to remove inotify watch.");
+	}
+}
+
+void arl_handle(void)
+{
+	ssize_t len;
+	char buf[4096] __attribute__ ((aligned(__alignof__(struct inotify_event))));
+	const struct inotify_event *event;
+	char *ptr;
+	char *fntmp, *fn;
+
+	len = read(autoreload.fd, buf, sizeof buf);
+	if (len == -1)
+	{
+		error(0, 0, "Failed to read inotify events.");
+		return;
+	}
+
+	for (ptr = buf; ptr < buf + len;
+			ptr += sizeof(struct inotify_event) + event->len)
+	{
+
+		event = (const struct inotify_event *) ptr;
+
+		/* events from watching the file itself */
+		if (event->mask & IN_CLOSE_WRITE)
+		{
+			load_image(fileidx);
+			redraw();
+		}
+
+		if (event->mask & IN_DELETE_SELF)
+			arl_setup_dir();
+
+		/* events from watching the file's directory */
+		if (event->mask & IN_CREATE)
+		{
+			fntmp = strdup(files[fileidx].path);
+			fn = basename(fntmp);
+
+			if (0 == strcmp(event->name, fn))
+			{
+				/* this is the file we're looking for */
+
+				/* cleanup, this has not been one-shot */
+				if (autoreload.watching_dir)
+				{
+					if(inotify_rm_watch(autoreload.fd, autoreload.wd))
+						error(0, 0, "Failed to remove inotify watch.");
+					autoreload.watching_dir = false;
+				}
+
+				/* when too fast, imlib2 can't load the image */
+				nanosleep(&ten_ms, NULL);
+				load_image(fileidx);
+				redraw();
+			}
+			free(fntmp);
+		}
+	}
+}
+
+void arl_init(void)
+{
+	/* this needs to be done only once */
+	autoreload.fd = inotify_init();
+	autoreload.watching_dir = false;
+	if (autoreload.fd == -1)
+		error(0, 0, "Could not initialize inotify.");
+}
+
+void arl_setup(void)
+{
+	if (autoreload.fd == -1)
+	{
+		error(0, 0, "Uninitialized, could not add inotify watch.");
+		return;
+	}
+
+	/* may have switched from a deleted to another image */
+	if (autoreload.watching_dir)
+	{
+		if (inotify_rm_watch(autoreload.fd, autoreload.wd))
+			error(0, 0, "Failed to remove inotify watch.");
+		autoreload.watching_dir = false;
+	}
+
+	autoreload.wd = inotify_add_watch(autoreload.fd, files[fileidx].path,
+		IN_ONESHOT | IN_CLOSE_WRITE | IN_DELETE_SELF);
+	if (autoreload.wd == -1)
+		error(0, 0, "Failed to add inotify watch on file '%s'.", files[fileidx].path);
+}
+
+void arl_setup_dir(void)
+{
+	char *dntmp, *dn;
+
+	if (autoreload.fd == -1)
+	{
+		error(0, 0, "Uninitialized, could not add inotify watch on directory.");
+		return;
+	}
+
+	/* get dirname */
+	dntmp = (char*) strdup(files[fileidx].path);
+	dn = (char*) dirname(dntmp);
+
+	/* this is not one-shot as other stuff may be created too
+	   note: we won't handle deletion of the directory itself,
+	     this is a design decision								*/
+	autoreload.wd = inotify_add_watch(autoreload.fd, dn,IN_CREATE);
+	if (autoreload.wd == -1)
+		error(0, 0, "Failed to add inotify watch on directory '%s'.", dn);
+	else
+		autoreload.watching_dir = true;
+
+	free(dntmp);
+}