hare

commit 6b851eaed490274d17c5cd7eb375a8bd064fad7f
parent f334db3ab5c3e91db8e9dc2aa95c166f372f10a7
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sat, 30 Jan 2021 19:16:31 -0500

os: getenv improvements

- accepts const str for name
- only converts input to UTF-8 once

After the next set of tagged union improvements, it should be possible
to set the return value type to (const str | void) as well.

Diffstat:
M
os/+linux/environ.ha
 | 
7
++++---
M
os/environ.ha
 | 
2
+-

2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/os/+linux/environ.ha b/os/+linux/environ.ha
@@ -31,15 +31,16 @@ let args_static: [32]str = [""...];
 };
 
 // Looks up an environment variable and returns its value, or void if unset.
-export fn getenv(name: str) (str | void) = {
-	// TODO: Type promotion can simplify this null comparison
+export fn getenv(name: const str) (str | void) = {
+	const name_b = strings::to_utf8(name);
+	// TODO: Type promotion can simplify this null comparison:
 	for (let i = 0z; rt::envp[i] != null: nullable *char; i += 1z) {
 		const item = rt::envp[i]: *[*]u8;
 		const eq: size = match (bytes::index(item[..], '=': u32: u8)) {
 			void => abort("Environment violates System-V invariants"),
 			i: size => i,
 		};
-		if (bytes::equal(strings::to_utf8(name), item[..eq])) {
+		if (bytes::equal(name_b, item[..eq])) {
 			const ln = strings::c_strlen(item: *const char);
 			return strings::from_utf8(item[eq+1z..ln]);
 		};
diff --git a/os/environ.ha b/os/environ.ha
@@ -1,5 +1,5 @@
 // Looks up an environment variable and returns its value. Aborts if unset.
-export fn must_getenv(name: str) str = {
+export fn must_getenv(name: const str) const str = {
 	// TODO: It would be nice to print the name of the variable in the error
 	match (getenv(name)) {
 		s: str => s,