From 97c471dc05b2b9c928758ae23f2f8cafd9d36dda Mon Sep 17 00:00:00 2001
From: Glenn Watson <gw@intuitionlibrary.com>
Date: Fri, 24 Oct 2014 14:49:07 +1000
Subject: [PATCH] Add an interface for providing system wide initialization
 options to the windowing system.

This allows setting up Linux based systems which use multithreaded OpenGL contexts.
---
 src/lib.rs                |  2 ++
 src/x11/ffi.rs            |  1 +
 src/x11/window/mod.rs     | 12 ++++++++++++
 src/x11/window/monitor.rs |  3 +++
 4 files changed, 18 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 041ebeb4..b443ab7c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -37,6 +37,8 @@ extern crate libc;
 extern crate cocoa;
 #[cfg(target_os = "macos")]
 extern crate core_foundation;
+#[cfg(target_os = "linux")]
+extern crate sync;
 
 pub use events::*;
 
diff --git a/src/x11/ffi.rs b/src/x11/ffi.rs
index 822f7558..f9dc3ad7 100644
--- a/src/x11/ffi.rs
+++ b/src/x11/ffi.rs
@@ -1410,6 +1410,7 @@ extern "C" {
     pub fn XMoveWindow(display: *mut Display, w: Window, x: libc::c_int, y: libc::c_int);
     pub fn XMapWindow(display: *mut Display, w: Window);
     pub fn XNextEvent(display: *mut Display, event_return: *mut XEvent);
+    pub fn XInitThreads() -> Status;
     pub fn XOpenDisplay(display_name: *const libc::c_char) -> *mut Display;
     pub fn XPeekEvent(display: *mut Display, event_return: *mut XEvent);
     pub fn XRefreshKeyboardMapping(event_map: *const XEvent);
diff --git a/src/x11/window/mod.rs b/src/x11/window/mod.rs
index cb73958c..9d29c072 100644
--- a/src/x11/window/mod.rs
+++ b/src/x11/window/mod.rs
@@ -3,12 +3,23 @@ use libc;
 use std::{mem, ptr};
 use std::sync::atomic::AtomicBool;
 use super::ffi;
+use sync::one::{Once, ONCE_INIT};
 
 pub use self::monitor::{MonitorID, get_available_monitors, get_primary_monitor};
 
 mod events;
 mod monitor;
 
+static THREAD_INIT: Once = ONCE_INIT;
+
+fn ensure_thread_init() {
+    THREAD_INIT.doit(|| {
+        unsafe {
+            ffi::XInitThreads();
+        }
+    });
+}
+
 pub struct Window {
     display: *mut ffi::Display,
     window: ffi::Window,
@@ -24,6 +35,7 @@ pub struct Window {
 
 impl Window {
     pub fn new(builder: WindowBuilder) -> Result<Window, String> {
+        ensure_thread_init();
         let dimensions = builder.dimensions.unwrap_or((800, 600));
 
         // calling XOpenDisplay
diff --git a/src/x11/window/monitor.rs b/src/x11/window/monitor.rs
index b72ed157..a9e77d79 100644
--- a/src/x11/window/monitor.rs
+++ b/src/x11/window/monitor.rs
@@ -1,9 +1,11 @@
 use std::{ptr};
 use super::super::ffi;
+use super::ensure_thread_init;
 
 pub struct MonitorID(pub uint);
 
 pub fn get_available_monitors() -> Vec<MonitorID> {
+    ensure_thread_init();
     let nb_monitors = unsafe {
         let display = ffi::XOpenDisplay(ptr::null());
         if display.is_null() {
@@ -20,6 +22,7 @@ pub fn get_available_monitors() -> Vec<MonitorID> {
 }
 
 pub fn get_primary_monitor() -> MonitorID {
+    ensure_thread_init();
     let primary_monitor = unsafe {
         let display = ffi::XOpenDisplay(ptr::null());
         if display.is_null() {