From 84a55da1ceea6559339cfb2d2866f40e6df32213 Mon Sep 17 00:00:00 2001
From: Casey Rodarmor <casey@rodarmor.com>
Date: Sat, 22 Apr 2017 21:39:29 -0700
Subject: [PATCH] Make shebangs work on windows (#185)

We use EXEPATH, which points to the root of the MinGW installation
and can be used as a base for translating the unix path to the
executable in the shebang line.

If we're not on MinGW, well, we just throw up our hands and hope
for the best.
---
 src/lib.rs      |  2 +-
 src/platform.rs | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index f45c5a5..200a1b1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -25,7 +25,7 @@ mod prelude {
   pub use std::io::prelude::*;
   pub use libc::{EXIT_FAILURE, EXIT_SUCCESS};
   pub use regex::Regex;
-  pub use std::path::Path;
+  pub use std::path::{Path, PathBuf};
   pub use std::{cmp, env, fs, fmt, io, iter, process};
 }
 
diff --git a/src/platform.rs b/src/platform.rs
index 007ce12..11f7f0e 100644
--- a/src/platform.rs
+++ b/src/platform.rs
@@ -44,7 +44,22 @@ impl PlatformInterface for Platform {
 #[cfg(windows)]
 impl PlatformInterface for Platform {
   fn make_shebang_command(path: &Path, command: &str, argument: Option<&str>) -> process::Command {
-    let mut cmd = process::Command::new(command);
+    let mut cmd = match env::var_os("EXEPATH") {
+      Some(exepath) => {
+        // On MinGW, `EXEPATH` is the root of the installation. Use it to
+        // construct a full windows path to the binary in the shebang line.
+        let mut translated_command = PathBuf::from(exepath);
+        for part in command.split("/") {
+            translated_command.push(part);
+        }
+        process::Command::new(translated_command)
+      }
+      None => {
+        // We're not on MinGW >_< The path in the shebang might be a windows
+        // path, in which case it'll work, so just use it and hope for the best.
+        process::Command::new(command)
+      }
+    };
     if let Some(argument) = argument {
       cmd.arg(argument);
     }