From d8a32a1005c33f6b95bbb3699a8f41ff5e19800e Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Mon, 9 Aug 2021 12:47:46 +0200
Subject: a sloppy implementation of path_simplify()

it's kinda bad. it passes the tests, though...
---
 src/kernel/vfs/path.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

(limited to 'src/kernel/vfs/path.c')

diff --git a/src/kernel/vfs/path.c b/src/kernel/vfs/path.c
index bd17e29..1cdcfe4 100644
--- a/src/kernel/vfs/path.c
+++ b/src/kernel/vfs/path.c
@@ -5,16 +5,22 @@ int path_simplify(const char *in, char *out, size_t len) {
 	if (len == 0)     return -1; // empty paths are invalid
 	if (in[0] != '/') return -1; // so are relative paths
 
-	int depth = 0;
+	int depth = 0; // shouldn't be needed!
 	int seg_len; // the length of the current path segment
+	int out_pos = 0;
+	bool directory = 0;
 
 	for (int i = 0; i < len; i += seg_len + 1) {
 		// TODO implement assert
 		if (in[i] != '/') panic();
 
 		seg_len = 0;
+		directory = false;
 		for (int j = i + 1; j < len; j++) {
-			if (in[j] == '/') break;
+			if (in[j] == '/') {
+				directory = true;
+				break;
+			}
 			seg_len++;
 		}
 
@@ -29,16 +35,31 @@ int path_simplify(const char *in, char *out, size_t len) {
 
 		if (seg_len == 0 || (seg_len == 1 && in[i + 1] == '.')) {
 			// the segment is // or /./
-			// the depth doesn't change
+			directory = true;
 		} else if (seg_len == 2 && in[i + 1] == '.' && in[i + 2] == '.') {
 			// the segment is /../
 			if (--depth < 0)
 				return -1;
+			// backtrack to last slash
+			while (out[--out_pos] != '/');
 		} else {
 			// normal segment
+			out[out_pos] = '/';
+			memcpy(&out[out_pos + 1], &in[i + 1], seg_len);
+			out_pos += seg_len + 1;
 			depth++;
 		}
+
 	}
 
-	return 1; // TODO
+	/* if we were backtracking, out_pos can become 0. i don't like this,
+	 * it feels sloppy. this algorithm should be implemented differently. TODO? */
+	if (out_pos == 0)
+		out[out_pos++] = '/';
+
+	if (directory) // if the path refers to a directory, append a trailing slash
+		if (out[out_pos-1] != '/') // unless it's already there
+			out[out_pos++] = '/';
+
+	return out_pos;
 }
-- 
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