From 8e371180022e848be965da128f554c69f633241e Mon Sep 17 00:00:00 2001
From: Pierre Curto <pierre.curto@gmail.com>
Date: Mon, 25 Sep 2023 08:41:51 +0200
Subject: [PATCH] std::os: add support for WIN32 in set_var and clear_var

Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
---
 lib/std/os/env.c3           | 27 ++++++++++++++++++++-------
 lib/std/os/win32/process.c3 |  4 ++++
 test/unit/stdlib/os/env.c3  | 17 +++++++++++++++++
 3 files changed, 41 insertions(+), 7 deletions(-)
 create mode 100644 test/unit/stdlib/os/env.c3

diff --git a/lib/std/os/env.c3 b/lib/std/os/env.c3
index 1bee1b80d..1491b8076 100644
--- a/lib/std/os/env.c3
+++ b/lib/std/os/env.c3
@@ -58,15 +58,24 @@ macro usz get_env_win32(name, buffer) @local
  **/
 fn void set_var(String name, String value, bool overwrite = true)
 {
-	$if env::LIBC && !env::WIN32:
 	@pool()
 	{
-		if (libc::setenv(name.zstr_tcopy(), value.zstr_copy(), (int)overwrite))
+		ZString zname = name.zstr_tcopy();
+		ZString zvalue = value.zstr_tcopy();
+	$switch
+	$case env::LIBC && !env::WIN32:
+		if (libc::setenv(zname, zvalue, (int)overwrite))
 		{
 			unreachable();
 		}
+	$case env::WIN32:
+		// https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setenvironmentvariable
+		if (!win32::setEnvironmentVariable((Win32_LPCSTR)zname.ptr, (Win32_LPCSTR)zvalue.ptr))
+		{
+			unreachable();
+		}
+	$endswitch
 	};
-	$endif
 }
 
 /**
@@ -124,21 +133,25 @@ fn String! get_config_dir(Allocator* using = mem::heap())
  **/
 fn void clear_var(String name)
 {
-	$if env::LIBC && !env::WIN32:
 	@pool()
 	{
-		if (libc::unsetenv(name.zstr_tcopy()))
+		ZString zname = name.zstr_tcopy();
+	$switch
+	$case env::LIBC && !env::WIN32:
+		if (libc::unsetenv(zname))
 		{
 			unreachable();
 		}
+	$case env::WIN32:
+		win32::getEnvironmentVariable((Win32_LPCSTR)zname.ptr, 0);
+	$endswitch
 	};
-	$endif
 }
 
 fn String! executable_path(Allocator *using = mem::heap())
 {
 	$if env::DARWIN:
-		return darwin::executable_path();
+		return darwin::executable_path(using);
 	$else
 		return "<Unsupported>";
 	$endif
diff --git a/lib/std/os/win32/process.c3 b/lib/std/os/win32/process.c3
index b4770a0ef..34e60a296 100644
--- a/lib/std/os/win32/process.c3
+++ b/lib/std/os/win32/process.c3
@@ -88,6 +88,10 @@ extern fn Win32_DWORD getEnvironmentVariable(
 	Win32_LPSTR lpBuffer,
 	Win32_DWORD nSize
 ) @extern("GetEnvironmentVariableA");
+extern fn Win32_BOOL setEnvironmentVariable(
+	Win32_LPCSTR lpName,
+	Win32_LPCSTR lpBuffer
+) @extern("SetEnvironmentVariableA");
 
 struct SystemInfo
 {
diff --git a/test/unit/stdlib/os/env.c3 b/test/unit/stdlib/os/env.c3
new file mode 100644
index 000000000..e7a9e3152
--- /dev/null
+++ b/test/unit/stdlib/os/env.c3
@@ -0,0 +1,17 @@
+module std::os::env @test;
+
+fn void! set_get_unset()
+{
+	const NAME = "C3_TEST_ENVVAR";
+	const VALUE = "foobar";
+
+	env::set_var(NAME, VALUE);
+	String v = env::get_var(NAME)!;
+	assert(v == VALUE, "got %s; want %s", v, VALUE);
+
+	env::clear_var(NAME);
+	if (try env::get_var(NAME))
+	{
+		assert(false, "environment variable should no longer exist");
+	}
+}
\ No newline at end of file