# HG changeset patch
# User feyu@google.com
# Date 2019-04-25 22:30:40
# Node ID c4a50e863ee2d66718161834d3f4d214f978a071
# Parent  4ad191041be2c05165098276a9453487633f2a1b

histedit: Speed up scrolling in patch view mode

Store patchcontents into the mode state, avoiding the expensive
call to ui for computing the patchcontents.

Before this change in large repos histedit patch view mode can
be very irresponsive.

diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -1079,6 +1079,8 @@ def movecursor(state, oldpos, newpos):
 def changemode(state, mode):
     curmode, _ = state['mode']
     state['mode'] = (mode, curmode)
+    if mode == MODE_PATCH:
+        state['modes'][MODE_PATCH]['patchcontents'] = patchcontents(state)
 
 def makeselection(state, pos):
     state['selected'] = pos
@@ -1134,7 +1136,7 @@ def changeview(state, delta, unit):
     if mode != MODE_PATCH:
         return
     mode_state = state['modes'][mode]
-    num_lines = len(patchcontents(state))
+    num_lines = len(mode_state['patchcontents'])
     page_height = state['page_height']
     unit = page_height if unit == 'page' else 1
     num_pages = 1 + (num_lines - 1) / page_height
@@ -1394,7 +1396,8 @@ pgup/K: move patch up, pgdn/J: move patc
 
     def renderpatch(win, state):
         start = state['modes'][MODE_PATCH]['line_offset']
-        renderstring(win, state, patchcontents(state)[start:], diffcolors=True)
+        content = state['modes'][MODE_PATCH]['patchcontents']
+        renderstring(win, state, content[start:], diffcolors=True)
 
     def layout(mode):
         maxy, maxx = stdscr.getmaxyx()