Scroll the goal and info buffers back to the top whenever they change

Author: Kyle Stemen

autoload/coquille.py

@@ -49,6 +49,27 @@ def vim_repr(value):
 def make_vim_range(start, stop):
     return [[start[0] + 1, start[2] + 1], [stop[0] + 1, stop[2] + 1]]
 
+# Return a list of all windows that are displaying the buffer, along with their
+# current cursor positions.
+def get_cursors_for_buffer(vim_buffer):
+    result = []
+    for win in vim.windows:
+        if win.buffer is vim_buffer:
+            result.append((win, win.cursor))
+    return result
+
+# Takes the list of window cursor positions from get_cursor_for_buffer. If the
+# cursor position is now lower for any of the windows, they are entered to
+# rescroll the window.
+def fix_scroll(cursors):
+    refresh_now = None
+    for win, (row, col) in cursors:
+        if win.cursor[0] < row or win.cursor[1] < col:
+            win.vars['coquille_needs_scroll_fix'] = 1
+            if win.tabpage is vim.current.tabpage:
+                vim.command("call coquille#FixWindowScrollTabWin(%d, %d)" %
+                    (win.tabpage.number, win.number))
+
 # All the python side state associated with the vim source buffer
 class BufferState(object):
     # Dict mapping source buffer id to BufferState
@@ -274,6 +295,7 @@ def show_goal(self, response):
         modifiable = self.goal_buffer.options["modifiable"]
         self.goal_buffer.options["modifiable"] = True
         try:
+            cursors = get_cursors_for_buffer(self.goal_buffer)
             del self.goal_buffer[:]
 
             if response is None:
@@ -320,6 +342,8 @@ def show_goal(self, response):
                 lines = map(lambda s: s.encode('utf-8'), ccl.split('\n'))
                 self.goal_buffer.append(list(lines))
                 self.goal_buffer.append('')
+
+            fix_scroll(cursors)
         finally:
             self.goal_buffer.options["modifiable"] = modifiable
         return True
@@ -329,6 +353,7 @@ def show_info(self, message):
         modifiable = self.info_buffer.options["modifiable"]
         self.info_buffer.options["modifiable"] = True
         try:
+            cursors = get_cursors_for_buffer(self.info_buffer)
             del self.info_buffer[:]
             lst = []
             if message is not None:
@@ -346,6 +371,7 @@ def show_info(self, message):
                 # extend function, and its append mostly behaves like extend.
                 self.info_buffer[0] = lst[0]
                 self.info_buffer.append(lst[1:])
+            fix_scroll(cursors)
         finally:
             self.info_buffer.options["modifiable"] = modifiable
 

autoload/coquille.vim

@@ -682,6 +682,36 @@ endfunction
 
 let s:empty_range = [ { 'line': 0, 'col': 0}, { 'line': 0, 'col': 0} ]
 
+function! coquille#FixWindowScroll(winid, hint_tabnr, hint_winnr)
+    let l:cur_tab = tabpagenr()
+    let l:cur_win = winnr()
+    let l:tabwin = coquille#WinId2TabWin(a:winid, a:hint_tabnr, a:hint_winnr)
+    if l:tabwin[0] != l:cur_tab
+        " Only fix the scroll for windows in the current tab. The other
+        " windows will be fixed when their tab is entered.
+        return 0
+    endif
+
+    if coquille#GetWinVar(a:winid, l:tabwin[0], l:tabwin[1],
+                \         "coquille_needs_scroll_fix", 0)
+        let l:cur_winid = coquille#WinGetId(l:cur_tab, l:cur_win)
+        call coquille#SetWinVar(a:winid, l:tabwin[0], l:tabwin[1],
+                    \           "coquille_needs_scroll_fix", 0)
+        " When the cursor is at the last line of the buffer, then the number
+        " of lines in the buffer is reduced from python, vim leaves the window
+        " scrolled past the end. Just entering the window is enough to fix it.
+        call coquille#WinGoToId(a:winid, l:tabwin[0], l:tabwin[1])
+
+        call coquille#WinGoToId(l:cur_winid, l:cur_tab, l:cur_win)
+        return 1
+    endif
+endfunction
+
+function! coquille#FixWindowScrollTabWin(tabnr, winnr)
+    let l:winid = coquille#WinGetId(a:tabnr, a:winnr)
+    return coquille#FixWindowScroll(l:winid, a:tabnr, a:winnr)
+endfunction
+
 function! coquille#SyncWindowColors(winid, hint_tabnr, hint_winnr)
     let l:cur_tab = tabpagenr()
     let l:cur_win = winnr()
@@ -772,8 +802,10 @@ function! coquille#TabActivated()
     while l:cur_win <= tabpagewinnr(l:cur_tab, "$")
         let l:cur_winid = coquille#WinGetId(l:cur_tab, l:cur_win)
         call coquille#SyncWindowColors(l:cur_winid, l:cur_tab, l:cur_win)
+        call coquille#FixWindowScroll(l:cur_winid, l:cur_tab, l:cur_win)
         let l:cur_win += 1
     endwhile
+
 endfunction
 
 function! coquille#WindowActivated(winid, hint_tabnr, hint_winnr)