From de70369f919388ec3f131e8a80effe4c3b16b9f5 Mon Sep 17 00:00:00 2001
From: Mart Lubbers <mart@martlubbers.net>
Date: Thu, 19 May 2016 12:35:13 +0200
Subject: [PATCH] Read PNG from stdin when no argument is given

Change -i to optional_argument
When image_path is the empty string assume stdin
---
 i3lock.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/i3lock.c b/i3lock.c
index 928953b..f712e52 100644
--- a/i3lock.c
+++ b/i3lock.c
@@ -743,6 +743,13 @@ static void raise_loop(xcb_window_t window) {
     }
 }
 
+cairo_status_t img_read(void *closure, unsigned char *data,
+                        unsigned int length) {
+    return fread(data, 1, length, stdin) == length ? CAIRO_STATUS_SUCCESS
+                                                   : CAIRO_STATUS_READ_ERROR;
+    (void)closure;
+}
+
 int main(int argc, char *argv[]) {
     struct passwd *pw;
     char *username;
@@ -762,7 +769,7 @@ int main(int argc, char *argv[]) {
         {"debug", no_argument, NULL, 0},
         {"help", no_argument, NULL, 'h'},
         {"no-unlock-indicator", no_argument, NULL, 'u'},
-        {"image", required_argument, NULL, 'i'},
+        {"image", optional_argument, NULL, 'i'},
         {"tiling", no_argument, NULL, 't'},
         {"ignore-empty-password", no_argument, NULL, 'e'},
         {"inactivity-timeout", required_argument, NULL, 'I'},
@@ -774,7 +781,7 @@ int main(int argc, char *argv[]) {
     if ((username = pw->pw_name) == NULL)
         errx(EXIT_FAILURE, "pw->pw_name is NULL.\n");
 
-    char *optstring = "hvnbdc:p:ui:teI:f";
+    char *optstring = "hvnbdc:p:ui::teI:f";
     while ((o = getopt_long(argc, argv, optstring, longopts, &optind)) != -1) {
         switch (o) {
             case 'v':
@@ -811,7 +818,10 @@ int main(int argc, char *argv[]) {
                 unlock_indicator = false;
                 break;
             case 'i':
-                image_path = strdup(optarg);
+                if (optarg == NULL)
+                    image_path = "";
+                else
+                    image_path = strdup(optarg);
                 break;
             case 't':
                 tile = true;
@@ -933,7 +943,11 @@ int main(int argc, char *argv[]) {
 
     if (image_path) {
         /* Create a pixmap to render on, fill it with the background color */
-        img = cairo_image_surface_create_from_png(image_path);
+        if (strlen(image_path) == 0)
+            img = cairo_image_surface_create_from_png_stream(img_read, NULL);
+        else
+            img = cairo_image_surface_create_from_png(image_path);
+
         /* In case loading failed, we just pretend no -i was specified. */
         if (cairo_surface_status(img) != CAIRO_STATUS_SUCCESS) {
             fprintf(stderr, "Could not load image \"%s\": %s\n",