1 files changed, 68 insertions, 0 deletions
diff --git a/third_party/rust/dwrote/src/helpers.rs b/third_party/rust/dwrote/src/helpers.rs
new file mode 100644
index 0000000000..804ff9e40c
--- /dev/null
+++ b/third_party/rust/dwrote/src/helpers.rs
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::ffi::OsStr;
+use std::os::windows::ffi::OsStrExt;
+use winapi::ctypes::wchar_t;
+use winapi::shared::minwindef::{BOOL, FALSE};
+use winapi::shared::winerror::S_OK;
+use winapi::um::dwrite::IDWriteLocalizedStrings;
+use winapi::um::winnls::GetUserDefaultLocaleName;
+use wio::com::ComPtr;
+
+lazy_static! {
+    static ref SYSTEM_LOCALE: Vec<wchar_t> = {
+        unsafe {
+            let mut locale: Vec<wchar_t> = vec![0; 85];
+            GetUserDefaultLocaleName(locale.as_mut_ptr(), locale.len() as i32 - 1);
+            locale
+        }
+    };
+    static ref EN_US_LOCALE: Vec<wchar_t> = { OsStr::new("en-us").to_wide_null() };
+}
+
+pub fn get_locale_string(strings: &mut ComPtr<IDWriteLocalizedStrings>) -> String {
+    unsafe {
+        let mut index: u32 = 0;
+        let mut exists: BOOL = FALSE;
+        let hr = strings.FindLocaleName((*SYSTEM_LOCALE).as_ptr(), &mut index, &mut exists);
+        if hr != S_OK || exists == FALSE {
+            let hr = strings.FindLocaleName((*EN_US_LOCALE).as_ptr(), &mut index, &mut exists);
+            if hr != S_OK || exists == FALSE {
+                // Ultimately fall back to first locale on list
+                index = 0;
+            }
+        }
+
+        let mut length: u32 = 0;
+        let hr = strings.GetStringLength(index, &mut length);
+        assert!(hr == 0);
+
+        let mut name: Vec<wchar_t> = Vec::with_capacity(length as usize + 1);
+        let hr = strings.GetString(index, name.as_mut_ptr(), length + 1);
+        assert!(hr == 0);
+        name.set_len(length as usize);
+
+        String::from_utf16(&name).ok().unwrap()
+    }
+}
+
+// ToWide from https://github.com/retep998/wio-rs/blob/master/src/wide.rs
+
+pub trait ToWide {
+    fn to_wide(&self) -> Vec<u16>;
+    fn to_wide_null(&self) -> Vec<u16>;
+}
+
+impl<T> ToWide for T
+where
+    T: AsRef<OsStr>,
+{
+    fn to_wide(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().collect()
+    }
+    fn to_wide_null(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().chain(Some(0)).collect()
+    }
+}