--- loncom/interface/londocs.pm	2008/12/13 00:19:07	1.320
+++ loncom/interface/londocs.pm	2008/12/15 06:32:01	1.323
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Documents
 #
-# $Id: londocs.pm,v 1.320 2008/12/13 00:19:07 raeburn Exp $
+# $Id: londocs.pm,v 1.323 2008/12/15 06:32:01 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1270,7 +1270,9 @@ ENDPASTE
 sub do_paste_from_buffer {
     my ($coursenum,$coursedom,$folder) = @_;
 
-    return 0 if (!$env{'form.pastemarked'});
+    if (!$env{'form.pastemarked'}) {
+        return;
+    }
 
 # paste resource to end of list
     my $url=&LONCAPA::map::qtescape($env{'docs.markedcopy_url'});
@@ -1278,13 +1280,45 @@ sub do_paste_from_buffer {
 # Maps need to be copied first
     if (($url=~/\.(page|sequence)$/) && ($url=~/^\/uploaded\//)) {
 	$title=&mt('Copy of').' '.$title;
-	my $newid=$$.time;
-	$url=~/^(.+)\.(\w+)$/;
-	my $newurl=$1.$newid.'.'.$2;
+	my $newid=$$.int(rand(100)).time;
+	my ($oldid,$ext) = ($url=~/^(.+)\.(\w+)$/);
+        if ($oldid =~ m{^(/uploaded/\Q$coursedom\E/\Q$coursenum\E/)(\D+)(\d+)$}) {
+            my $path = $1;
+            my $prefix = $2;
+            my $ancestor = $3;
+            if (length($ancestor) > 10) {
+                $ancestor = substr($ancestor,-10,10);
+            }
+            $oldid = $path.$prefix.$ancestor;
+        }
+        my $counter = 0;
+        my $newurl=$oldid.$newid.'.'.$ext;
+        my $is_unique = &uniqueness_check($newurl);
+        while (!$is_unique && $counter < 100) {
+            $counter ++;
+            $newid ++;
+            $newurl = $oldid.$newid;
+            $is_unique = &uniqueness_check($newurl);
+        }
+        if (!$is_unique) {
+            if ($url=~/\.page$/) {
+                return &mt('Paste failed: an error occurred creating a unique URL for the composite page');
+            } else {
+                return &mt('Paste failed: an error occurred creating a unique URL for the folder');
+            }
+        }
 	my $storefn=$newurl;
 	$storefn=~s{^/\w+/$match_domain/$match_username/}{};
-	&Apache::lonclonecourse::writefile($env{'request.course.id'},$storefn,
-					   &Apache::lonnet::getfile($url));
+	my $paste_map_result =
+            &Apache::lonclonecourse::writefile($env{'request.course.id'},$storefn,
+					       &Apache::lonnet::getfile($url));
+        if ($paste_map_result eq '/adm/notfound.html') {
+            if ($url=~/\.page$/) {
+                return &mt('Paste failed: an error occurred saving the composite page');
+            } else {
+                return &mt('Paste failed: an error occurred saving the folder');
+            }
+        }
 	$url = $newurl;
     }
 # published maps can only exists once, so remove it from paste buffer when done
@@ -1326,9 +1360,24 @@ sub do_paste_from_buffer {
 
     $LONCAPA::map::resources[$newidx]= 	$title.':'.$url.':'.$ext.':normal:res';
     push(@LONCAPA::map::order, $newidx);
+    return 'ok';
 # Store the result
 }
 
+sub uniqueness_check {
+    my ($newurl) = @_;
+    my $unique = 1;
+    foreach my $res (@LONCAPA::map::order) {
+        my ($name,$url)=split(/\:/,$LONCAPA::map::resources[$res]);
+        $url=&LONCAPA::map::qtescape($url);
+        if ($newurl eq $url) {
+            $unique = 0;
+            last;    
+        }
+    }
+    return $unique;
+}
+
 my %parameter_type = ( 'randompick'     => 'int_pos',
 		       'hiddenresource' => 'string_yesno',
 		       'encrypturl'     => 'string_yesno',
@@ -1444,9 +1493,14 @@ sub editor {
 	}
 	    
 	if ($env{'form.pastemarked'}) {
-	    &do_paste_from_buffer($coursenum,$coursedom,$folder);
-	    ($errtext,$fatal) = &storemap($coursenum,$coursedom,$folder.'.'.$container);
-	    return $errtext if ($fatal);
+            my $paste_res = 
+                &do_paste_from_buffer($coursenum,$coursedom,$folder);
+            if ($paste_res eq 'ok') {
+                ($errtext,$fatal) = &storemap($coursenum,$coursedom,$folder.'.'.$container);
+                return $errtext if ($fatal);
+            } elsif ($paste_res ne '') {
+                $r->print('<p><span class="LC_error">'.$paste_res.'</span></p>');
+            }
 	}
 
 	$r->print($upload_output);