From: Lady <redacted>
Date: Fri, 28 Mar 2025 17:44:56 +0000 (-0400)
Subject: Drop `assert()´ check in subpath parsing
X-Git-Url: https://git.ladys.computer/CGirls/commitdiff_plain

Drop `assert()´ check in subpath parsing

This is a minor refactor to use `for´ loops instead of `while´ ones
when parsing subpaths, and to condition exiting the second loop on
filling the array, rather than on reaching the end of the string. If
there is a bug in the code which causes the array to be too small, this
will simply clip the result rather than try to assign to out‐of‐bounds
memory. If there is a bug in the code which causes the array to be too
big, the program will loop endlessly rather than fail an `assert()´
check. The improvement in the first case is deemed to justify the
slight degradation of behaviour in the second.
---

diff --git a/request.c b/request.c
index b868812..f9fa453 100644
--- a/request.c
+++ b/request.c
@@ -164,10 +164,13 @@ cgirls_req cgirls_path·to·req(char const*const pathinfo) {
 	// The portion of the pathinfo which follows the third slash is the
 	// subpath of the request. An empty sting is equivalent to having no
 	// subpath. Trailing and successive slashes are dropped.
-	char const* sos = ndx[0];
 	char const* sep = nullptr;
 	size_t n·s = 0;
-	while (end[0] > sos) {
+	for (
+		char const* sos = ndx[0];
+		sos < end[0];
+		sos = (end[0] > sep ? sep + 1 : end[0])
+	) {
 		// Count the number of segments in the pathinfo so that the correct
 		// amount of space can be allocated.
 		sep = strchr(sos, '/');
@@ -177,34 +180,28 @@ cgirls_req cgirls_path·to·req(char const*const pathinfo) {
 		if (sep > sos) {
 			++n·s;
 		}
-		if (end[0] > sep) {
-			sos = sep + 1;
-		} else {
-			sos = end[0];
-		}
-	}
-	req.subpath = calloc(n·s + 1, sizeof(char*));
-	if (!req.subpath) {
-		return req;
 	}
-	size_t i·s = 0;
-	while (end[0] > ndx[0]) {
-		// Add the segments to the newly allocated array.
-		sep = strchr(ndx[0], '/');
-		if (!sep) {
-			sep = end[0];
+	if (n·s > 0) {
+		req.subpath = calloc(n·s + 1, sizeof(char*));
+		if (!req.subpath) {
+			return req;
 		}
-		if (sep > ndx[0]) {
-			req.subpath[i·s++] = strndup(ndx[0], sep - ndx[0]);
-		}
-		if (end[0] > sep) {
-			ndx[0] = sep + 1;
-		} else {
-			ndx[0] = end[0];
+		for (
+			size_t i·s = 0;
+			i·s < n·s;
+			ndx[0] = (end[0] > sep ? sep + 1 : end[0])
+		) {
+			// Add the segments to the newly allocated array.
+			sep = strchr(ndx[0], '/');
+			if (!sep) {
+				sep = end[0];
+			}
+			if (sep > ndx[0]) {
+				req.subpath[i·s++] = strndup(ndx[0], sep - ndx[0]);
+			}
 		}
+		req.subpath[n·s] = nullptr;
 	}
-	assert(i·s == n·s);
-	req.subpath[i·s] = nullptr;
 
 	// Return the result.
 	return req;