From a3c4954710361ec94552c0999b4426e26a58f0fc Mon Sep 17 00:00:00 2001
From: scott <scott>
Date: Wed, 28 Jan 1998 18:20:32 +0000
Subject: [PATCH] Added safety code for add channel so you can't add a channel
 twice or to the wrong image.  (Same thing as I did for layers a few months
 ago.) --sg

---
 ChangeLog    |  6 ++++++
 app/gimage.c | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index c721451bb9..135657a98e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Jan 28 13:17:06 1998  Scott Goehring  <scott@poverty.bloomington.in.us>
+
+	* app/gimage.c (gimage_add_channel): Added safety code for add
+	channel so you can't add a channel twice or to the wrong image.
+	(Same thing as I did for layers a few months ago.)
+
 Tue Jan 27 22:31:00 PST 1998 Raph Levien <raph@acm.org>
 
 	* app/gimage_mask.c: hacked around fractional pixel errors in
diff --git a/app/gimage.c b/app/gimage.c
index 23c6addfc9..d45d502ddf 100644
--- a/app/gimage.c
+++ b/app/gimage.c
@@ -2401,6 +2401,27 @@ gimage_add_channel (GImage *gimage, Channel *channel, int position)
 {
   ChannelUndo * cu;
 
+  if (GIMP_DRAWABLE(channel)->gimage_ID != 0 &&
+      GIMP_DRAWABLE(channel)->gimage_ID != gimage->ID)
+    {
+      warning("gimage_add_channel: attempt to add channel to wrong image");
+      return NULL;
+    }
+
+  {
+    link_ptr cc = gimage->channels;
+    while (cc) 
+      {
+	if (cc->data == channel) 
+	  {
+	    warning("gimage_add_channel: trying to add channel to image twice");
+	    return NULL;
+	  }
+	cc = next_item(cc);
+      }
+  }  
+
+
   /*  Prepare a channel undo and push it  */
   cu = (ChannelUndo *) g_malloc (sizeof (ChannelUndo));
   cu->channel = channel;