small performance increase

autoload/ctrlp.vim

@@ -249,12 +249,14 @@ func! s:GetMatchedItems(items, pats, limit) "{{{
 	cal map(pats, 'substitute(v:val, "\\\~", "\\\\\\~", "g")')
 	" loop through the patterns
 	for each in pats
+		" if newitems is small, set it as items to search in
 		if exists('newitems') && len(newitems) < limit
-			let items = newitems
+			let items = deepcopy(newitems)
+			let s:matcheditems = deepcopy(items)
 		endif
-		if empty(items)
+		if empty(items) " end here
 			retu exists('newitems') ? newitems : []
-		else
+		else " start here, goes back up if has 2 or more in pats
 			let newitems = []
 			" loop through the items
 			for item in items
@@ -391,19 +393,36 @@ func! s:Renderer(lines) "{{{
 		cal setline('1', ' == NO MATCHES ==')
 	endif
 	" Remember selected line
-	if exists('g:CtrlP_cline')
+	if exists('g:CtrlP_cline') && s:pinput == 2
 		cal setpos('.', [0, g:CtrlP_cline, 1, 0])
 	endif
 endfunc "}}}
 
 func! s:UpdateMatches(pat) "{{{
 	" Delete the buffer's content
 	sil! %d _
-	let newpat = s:SplitPattern(a:pat)
-	let lines  = s:GetMatchedItems(s:lines, newpat, s:mxheight)
+	let items = s:LinesFilter()
+	let pats  = s:SplitPattern(a:pat)
+	let lines = s:GetMatchedItems(items, pats, s:mxheight)
 	cal s:Renderer(lines)
 endfunc "}}}
 
+func! s:LinesFilter() "{{{
+	" tiny performance increase, but every little bit counts
+	if exists('g:CtrlP_prompt_prev')
+		let prt      = g:CtrlP_prompt
+		let prt_prev = g:CtrlP_prompt_prev
+		let str      = prt[0] . prt[1] . prt[2]
+		let str_prev = prt_prev[0] . prt_prev[1] . prt_prev[2]
+	endif
+	if exists('s:matcheditems') && len(s:matcheditems) < s:mxheight
+				\ && exists('str') && match(str, str_prev) >= 0
+		retu s:matcheditems
+	else
+		retu s:lines
+	endif
+endfunc "}}}
+
 func! s:BuildPrompt(...) "{{{
 	let base1 = s:regexp ? 'r' : '>'
 	let base2 = s:byfname ? 'd' : '>'
@@ -448,6 +467,7 @@ endfunc
 
 func! s:PrtAdd(char)
 	let prt = g:CtrlP_prompt
+	let g:CtrlP_prompt_prev = deepcopy(g:CtrlP_prompt)
 	let prt[0] = prt[0] . a:char
 	cal s:BuildPrompt()
 endfunc

doc/ctrlp.txt

@@ -51,8 +51,9 @@ setting is from bottom to top: >
 <
 
                                                    *'g:ctrlp_persistent_input'*
-Remember the last input string and position of the selection in the match
-window: >
+Remember the last input string. Set this to 2 to also remember the last
+position of the selection in the match window and 0 to completely disable this
+feature: >
   let g:ctrlp_persistent_input = 1
 <
 
@@ -352,9 +353,10 @@ CHANGELOG
 
                                                                *ctrlp-update-2*
 Update #2~
+    + Extended the behavior of |g:ctrlp_persistent_input|
+    + New option: |g:ctrlp_dotfiles|
     + New input format: '..' (section 5.d)
     + New mapping: <F5>.
-    + New option: |g:ctrlp_dotfiles|
     + New commands: |:CtrlPCurWD|,
                     |:CtrlPCurFile|,
                     |:CtrlPRoot|