From 01de38b20d94436492e351a75e2f29e9bab3aac9 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 31 May 2023 22:03:27 -0700
Subject: [PATCH] font: if CoreText needs to allocate, stack allocate and log

---
 src/font/DeferredFace.zig | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/font/DeferredFace.zig b/src/font/DeferredFace.zig
index 94fd7bd10..a91589b59 100644
--- a/src/font/DeferredFace.zig
+++ b/src/font/DeferredFace.zig
@@ -113,7 +113,21 @@ pub fn name(self: DeferredFace) ![:0]const u8 {
 
         .coretext, .coretext_freetype => if (self.ct) |ct| {
             const display_name = ct.font.copyDisplayName();
-            return display_name.cstringPtr(.utf8) orelse "<unsupported internal encoding>";
+            return display_name.cstringPtr(.utf8) orelse unsupported: {
+                // "NULL if the internal storage of theString does not allow
+                // this to be returned efficiently." In this case, we need
+                // to allocate. But we can't return an allocated string because
+                // we don't have an allocator. Let's use the stack and log it.
+                var buf: [1024]u8 = undefined;
+                const buf_name = display_name.cstring(&buf, .utf8) orelse
+                    "<not enough internal storage space>";
+
+                log.info(
+                    "CoreText font required too much space to copy, value = {s}",
+                    .{buf_name},
+                );
+                break :unsupported "<CoreText internal storage limited, see logs>";
+            };
         },
 
         .web_canvas => if (self.wc) |wc| return wc.font_str,