From 701102d44b813ac5d6b8c6e9673c8b74a4109f07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A1szl=C3=B3=20V=C3=A1rady?= <laszlo.varady93@gmail.com>
Date: Sat, 28 Jan 2017 23:26:42 +0100
Subject: [PATCH] fix(cairo): Fix font prioritization

In the previous implementation, std::find() returned fns.end() several times,
which caused an "Address boundary error" in std::sort if the preferred
font-index was set to m_fonts.size() + 1.

This commit reimplements the font prioritization with a simple swap.

Reproduction steps:

- Start polybar with the following config:

  [bar/top]
  font-0 = NotoSans-Regular:size=8;0
  font-1 = MaterialIcons:size=10;0

  modules-left = date

  [module/date]
  type = internal/date
  date = %Y-%m-%d
  label-font = 3 ; invalid index
---
 include/cairo/context.hpp | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/cairo/context.hpp b/include/cairo/context.hpp
index 75ef4636..98623d38 100644
--- a/include/cairo/context.hpp
+++ b/include/cairo/context.hpp
@@ -145,16 +145,12 @@ namespace cairo {
       double x, y;
       position(&x, &y);
 
-      // Sort the fontlist so that the
-      // preferred font gets prioritized
+      // Prioritize the preferred font
       vector<shared_ptr<font>> fns(m_fonts.begin(), m_fonts.end());
-      std::sort(fns.begin(), fns.end(), [&](const shared_ptr<font>& a, const shared_ptr<font>&) {
-        if (t.font > 0 && std::distance(fns.begin(), std::find(fns.begin(), fns.end(), a)) == t.font - 1) {
-          return -1;
-        } else {
-          return 0;
-        }
-      });
+
+      if (t.font > 0 && t.font <= std::distance(fns.begin(), fns.end())) {
+        std::iter_swap(fns.begin(), fns.begin() + t.font - 1);
+      }
 
       string utf8 = string(t.contents);
       utils::unicode_charlist chars;