hare

commit 5d22b63c9cb0325eeadeddb957f6369439803d43
parent bae714096f1a0571b82261d33644223fb2957cc2
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sun,  7 Mar 2021 09:25:06 -0500

path: add path::extension

Diffstat:
M
hare/module/scan.ha
 | 
12
+++++++-----
M
path/names.ha
 | 
44
+++++++++++++++++++++++++++++++++++++++++++-

2 files changed, 50 insertions(+), 6 deletions(-)
diff --git a/hare/module/scan.ha b/hare/module/scan.ha
@@ -79,19 +79,21 @@ export fn lookup(ctx: *context, name: ast::ident) (version | error) = {
 	return module_not_found;
 };
 
-// TODO: Filter inputs by build tags
 fn eligible(ctx: *context, name: path::path) bool = {
 	if (!(name is str)) {
 		return false;
 	};
-	let name = name as str;
+	let eligible = false;
+	const ext = path::extension(name);
 	static const exts = [".ha", ".s"];
 	for (let i = 0z; i < len(exts); i += 1) {
-		if (strings::has_suffix(name, exts[i])) {
-			return true;
+		if (exts[i] == ext) {
+			eligible = true;
+			break;
 		};
 	};
-	return false;
+	// TODO: Check build tags as well
+	return eligible;
 };
 
 fn scan_file(
diff --git a/path/names.ha b/path/names.ha
@@ -1,4 +1,5 @@
 use bytes;
+use encoding::utf8;
 use strings;
 
 // Returns the directory name for a given path. For a path to a file name, this
@@ -61,4 +62,45 @@ export fn basename(path: path::path) path::path = {
 };
 
 // Returns true if the given path is a root directory.
-export fn is_root(path: path::path) bool = len(pathbytes(path)) == 1;
+export fn is_root(path: path::path) bool = {
+	let b = pathbytes(path);
+	if (len(b) == 0) {
+		return false;
+	};
+	return b[0] == PATHSEP;
+};
+
+// Returns the file extension for a path. This presumes that the file extension
+// is a valid UTF-8 string, if not, it will return an empty string. The return
+// value is borrowed from the input, see [strings::dup] to extend its lifetime.
+//
+// The return value includes the '.' character.
+//
+// extension("foo/example") => ""
+// extension("foo/example.txt") => ".txt"
+// extension("foo/example.tar.gz") => ".tar.gz"
+export fn extension(p: path::path) str = {
+	let b = pathbytes(p);
+	if (len(b) == 0 || b[len(b) - 1] == PATHSEP) {
+		return "";
+	};
+	let b = pathbytes(basename(p));
+	let i = match (bytes::index(b, '.': u32: u8)) {
+		void => return "",
+		z: size => z,
+	};
+	let e = b[i..];
+	return match (strings::try_from_utf8(e)) {
+		utf8::invalid => "",
+		s: str => s,
+	};
+};
+
+@test fn extension() void = {
+	assert(extension("") == "");
+	assert(extension("foo/") == "");
+	assert(extension("foo/bar") == "");
+	assert(extension("foo/bar.txt") == ".txt");
+	assert(extension("foo/bar.tar.gz") == ".tar.gz");
+	assert(extension("foo.bar/baz.ha") == ".ha");
+};