Add autoreload support by inotify (and dummy backend nop)

Makefile

@@ -24,6 +24,13 @@ endif
 .PHONY: clean install uninstall
 
 SRC := commands.c image.c main.c options.c thumbs.c util.c window.c
+# conditionally compile in autoreload-backend; usage: `make AUTORELOAD=nop`
+ifeq ($(AUTORELOAD),nop)
+	SRC += autoreload_nop.c
+else
+	SRC += autoreload_inotify.c
+endif
+
 DEP := $(SRC:.c=.d)
 OBJ := $(SRC:.c=.o)
 

autoreload.h

@@ -0,0 +1,43 @@
+/* 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/>.
+ */
+
+#ifndef AUTORELOAD_H
+#define AUTORELOAD_H
+
+#include "types.h"
+
+void arl_cleanup(void);
+void arl_handle(void);
+void arl_init(void);
+void arl_setup(void);
+void arl_setup_dir(void);
+
+typedef struct {
+	int fd;
+	int wd;
+	bool watching_dir;
+} autoreload_t;
+
+extern autoreload_t autoreload;
+extern int fileidx;
+extern fileinfo_t *files;
+
+void load_image(int);
+void redraw(void);
+
+#endif /* AUTORELOAD_H */

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);
+}

autoreload_nop.c

@@ -0,0 +1,31 @@
+/* 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 "autoreload.h"
+
+void arl_cleanup(void) { }
+
+void arl_handle(void) { }
+
+void arl_init(void) { }
+
+void arl_setup(void) { }
+
+void arl_setup_dir(void) { }
+
+

main.c

@@ -38,6 +38,7 @@
 #include "thumbs.h"
 #include "util.h"
 #include "window.h"
+#include "autoreload.h"
 
 #define _MAPPINGS_CONFIG
 #include "config.h"
@@ -64,6 +65,7 @@ fileinfo_t *files;
 int filecnt, fileidx;
 int alternate;
 int markcnt;
+autoreload_t autoreload;
 
 int prefix;
 bool extprefix;
@@ -98,6 +100,7 @@ timeout_t timeouts[] = {
 void cleanup(void)
 {
 	img_close(&img, false);
+	arl_cleanup();
 	tns_free(&tns);
 	win_close(&win);
 }
@@ -317,6 +320,7 @@ void load_image(int new)
 
 	info.open = false;
 	open_info();
+	arl_setup();
 
 	if (img.multi.cnt > 0 && img.multi.animate)
 		set_timeout(animate, img.multi.frames[img.multi.sel].delay, true);
@@ -685,7 +689,7 @@ void run(void)
 		init_thumb = mode == MODE_THUMB && tns.initnext < filecnt;
 		load_thumb = mode == MODE_THUMB && tns.loadnext < tns.end;
 
-		if ((init_thumb || load_thumb || to_set || info.fd != -1) &&
+		if ((init_thumb || load_thumb || to_set || info.fd != -1 || autoreload.fd != -1) &&
 		    XPending(win.env.dpy) == 0)
 		{
 			if (load_thumb) {
@@ -708,9 +712,15 @@ void run(void)
 					FD_SET(info.fd, &fds);
 					xfd = MAX(xfd, info.fd);
 				}
+				if (autoreload.fd != -1) {
+					FD_SET(autoreload.fd, &fds);
+					xfd = MAX(xfd, autoreload.fd);
+				}
 				select(xfd + 1, &fds, 0, 0, to_set ? &timeout : NULL);
 				if (info.fd != -1 && FD_ISSET(info.fd, &fds))
 					read_info();
+				if (autoreload.fd != -1 && FD_ISSET(autoreload.fd, &fds))
+					arl_handle();
 			}
 			continue;
 		}
@@ -854,6 +864,7 @@ int main(int argc, char **argv)
 
 	win_init(&win);
 	img_init(&img, &win);
+	arl_init();
 
 	if ((homedir = getenv("XDG_CONFIG_HOME")) == NULL || homedir[0] == '\0') {
 		homedir = getenv("HOME");