# HG changeset patch
# User Miroslav Rezanina <mrezanin@redhat.com>
# Date 1323790700 0
# Node ID c04ec56f4a6d381bfacd31fbcaefdaa206a914f1
# Parent  63e5005d58ca5674e790ef627e7fb3c8c66c5374
pygrub: Allow scrolling of the list of entries

When user wants to change entry in grub2 menu in pygrub, there
may be crash of pygrub in case of editing item ('e' key).

Crash on editing is caused longer entry list in case of grub2. As entry
window is 10 lines high, it can hold only 8 entries (2 lines for border).
Adding line outside of windows high causes crash. Patch add handling
for longer lists and scrolling through them.

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff -r 63e5005d58ca -r c04ec56f4a6d tools/pygrub/src/pygrub
--- a/tools/pygrub/src/pygrub	Tue Dec 13 15:31:12 2011 +0000
+++ b/tools/pygrub/src/pygrub	Tue Dec 13 15:38:20 2011 +0000
@@ -221,6 +221,7 @@
         
 
 class Grub:
+    ENTRY_WIN_LINES = 8
     def __init__(self, file, fs = None):
         self.screen = None
         self.entry_win = None
@@ -238,7 +239,7 @@
                 except:
                     pass # Not important if we can't use colour
             enable_cursor(False)
-            self.entry_win = curses.newwin(10, 74, 2, 1)
+            self.entry_win = curses.newwin(Grub.ENTRY_WIN_LINES + 2, 74, 2, 1)
             self.text_win = curses.newwin(10, 70, 12, 5)
             curses.def_prog_mode()
         
@@ -287,12 +288,20 @@
             self.text_win.noutrefresh()
 
         curline = 0
+        pos = 0
         img = copy.deepcopy(origimg)
         while 1:
             draw()
             self.entry_win.erase()
-            self.entry_win.box()
-            for idx in range(0, len(img.lines)):
+
+            rs = 0
+            re = len(img.lines)
+            idp = 1
+            if re > Grub.ENTRY_WIN_LINES:
+                rs = curline - pos
+                re = rs + Grub.ENTRY_WIN_LINES
+
+            for idx in range(rs, re):
                 # current line should be highlighted
                 if idx == curline:
                     self.entry_win.attron(curses.A_REVERSE)
@@ -302,9 +311,11 @@
                 if len(l) > 70:
                     l = l[:69] + ">"
                     
-                self.entry_win.addstr(idx + 1, 2, l)
+                self.entry_win.addstr(idp, 2, l)
                 if idx == curline:
                     self.entry_win.attroff(curses.A_REVERSE)
+                idp += 1
+            self.entry_win.box()
             self.entry_win.noutrefresh()
             curses.doupdate()
 
@@ -313,8 +324,12 @@
                 break
             elif c == curses.KEY_UP:
                 curline -= 1
+                if pos > 0:
+                    pos -= 1
             elif c == curses.KEY_DOWN:
                 curline += 1
+                if pos < Grub.ENTRY_WIN_LINES - 1:
+                    pos += 1
             elif c == ord('b'):
                 self.isdone = True
                 break