inputw: improve correctness and startup performance

a massive amount of time inside readstdin() is spent trying to get the
max input width and then put it into inputw, only for it to get clamped
down to mw/3 inside setup().

it makes more sense to calculate inputw inside setup() once we have mw
available. similar to the last patch, i see noticeable startup
performance improvement:

before -> after
160ms  -> 60ms

additionally this will take fallback fonts into account compared to the
previous version, so it's not only more performant but also more correct.

1 files changed, 9 insertions, 10 deletions

diff --git a/dmenu.c b/dmenu.c
index cde394b..d989d39 100644
--- a/dmenu.c
+++ b/dmenu.c
@@ -547,8 +547,7 @@ static void
 readstdin(void)
 {
         char buf[sizeof text], *p;
-        size_t i, imax = 0, size = 0;
-        unsigned int tmpmax = 0;
+        size_t i, size = 0;
 
         /* read each line from stdin and add it to the item list */
         for (i = 0; fgets(buf, sizeof buf, stdin); i++) {
@@ -560,15 +559,9 @@ readstdin(void)
                 if (!(items[i].text = strdup(buf)))
                         die("cannot strdup %u bytes:", strlen(buf) + 1);
                 items[i].out = 0;
-                drw_font_getexts(drw->fonts, buf, strlen(buf), &tmpmax, NULL);
-                if (tmpmax > inputw) {
-                        inputw = tmpmax;
-                        imax = i;
-                }
         }
         if (items)
                 items[i].text = NULL;
-        inputw = items ? TEXTW(items[imax].text) : 0;
         lines = MIN(lines, i);
 }
 
@@ -614,12 +607,13 @@ static void
 setup(void)
 {
         int x, y, i, j;
-        unsigned int du;
+        unsigned int du, tmp;
         XSetWindowAttributes swa;
         XIM xim;
         Window w, dw, *dws;
         XWindowAttributes wa;
         XClassHint ch = {"dmenu", "dmenu"};
+        struct item *item;
 #ifdef XINERAMA
         XineramaScreenInfo *info;
         Window pw;
@@ -677,7 +671,12 @@ setup(void)
                 mw = wa.width;
         }
         promptw = (prompt && *prompt) ? TEXTW(prompt) - lrpad / 4 : 0;
-        inputw = MIN(inputw, mw/3);
+        for (item = items; item && item->text; ++item) {
+                if ((tmp = textw_clamp(item->text, mw/3)) > inputw) {
+                        if ((inputw = tmp) == mw/3)
+                                break;
+                }
+        }
         match();
 
         /* create menu window */