From 4fd574cc7f0132099d6b66727d6edbd84d10bed3 Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Wed, 25 Nov 2020 15:05:18 -0800
Subject: [PATCH] freetype: enable FT_Error_String

By default, freetype doesn't include error strings and FT_Error_String
will always return NULL.  Turn on the compile time option that makes
this function useful!
---
 deps/freetype/build.rs     |  4 ++++
 wezterm-font/src/ftwrap.rs | 15 ++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/deps/freetype/build.rs b/deps/freetype/build.rs
index f33ada310..9fd3311cb 100644
--- a/deps/freetype/build.rs
+++ b/deps/freetype/build.rs
@@ -148,6 +148,10 @@ fn freetype() {
         build_dir.join("freetype2/include/freetype/config/ftoption.h"),
         fs::read_to_string("freetype2/include/freetype/config/ftoption.h")
             .unwrap()
+            .replace(
+                "/* #define FT_CONFIG_OPTION_ERROR_STRINGS */",
+                "#define FT_CONFIG_OPTION_ERROR_STRINGS",
+            )
             .replace(
                 "/* #define FT_CONFIG_OPTION_SYSTEM_ZLIB */",
                 "#define FT_CONFIG_OPTION_SYSTEM_ZLIB",
diff --git a/wezterm-font/src/ftwrap.rs b/wezterm-font/src/ftwrap.rs
index 1636f2c61..ac6b05914 100644
--- a/wezterm-font/src/ftwrap.rs
+++ b/wezterm-font/src/ftwrap.rs
@@ -16,7 +16,20 @@ fn ft_result<T>(err: FT_Error, t: T) -> anyhow::Result<T> {
     if succeeded(err) {
         Ok(t)
     } else {
-        Err(anyhow!("FreeType error {:?} 0x{:x}", err, err))
+        unsafe {
+            let reason = FT_Error_String(err);
+            if reason.is_null() {
+                Err(anyhow!("FreeType error {:?} 0x{:x}", err, err))
+            } else {
+                let reason = std::ffi::CStr::from_ptr(reason);
+                Err(anyhow!(
+                    "FreeType error {:?} 0x{:x}: {}",
+                    err,
+                    err,
+                    reason.to_string_lossy()
+                ))
+            }
+        }
     }
 }