From 4ee772b0507ba4755738990963f9625864f7380b Mon Sep 17 00:00:00 2001
From: WebFreak001 <gh@webfreak.org>
Date: Fri, 19 Apr 2019 12:10:21 +0200
Subject: [PATCH] adjust to review

---
 http/vibe/http/fileserver.d | 63 ++++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 19 deletions(-)

diff --git a/http/vibe/http/fileserver.d b/http/vibe/http/fileserver.d
index 66ed8e0868..25b7c68177 100644
--- a/http/vibe/http/fileserver.d
+++ b/http/vibe/http/fileserver.d
@@ -16,12 +16,13 @@ import vibe.inet.mimetypes;
 import vibe.inet.url;
 import vibe.internal.interfaceproxy;
 
+import std.algorithm;
 import std.conv;
 import std.datetime;
 import std.digest.md;
 import std.exception;
+import std.range : popFront, empty, drop;
 import std.string;
-import std.algorithm;
 
 @safe:
 
@@ -502,7 +503,7 @@ bool handleCache(scope HTTPServerRequest req, scope HTTPServerResponse res, ETag
 			res.headers["Cache-Control"] = cache_control;
 		}
 	} else if (max_age > Duration.zero) {
-		res.headers["Cache-Control"] = "max-age=" ~ to!string(max_age.total!"seconds");
+		res.headers["Cache-Control"] = text("max-age=", max_age.total!"seconds");
 	}
 
 	// https://tools.ietf.org/html/rfc7232#section-3.1
@@ -532,8 +533,8 @@ bool handleCache(scope HTTPServerRequest req, scope HTTPServerResponse res, ETag
 		// https://tools.ietf.org/html/rfc7232#section-3.3
 		string ifModifiedSince = req.headers.get("If-Modified-Since");
 		if (ifModifiedSince.length) {
-			const check = lastModifiedString == ifModifiedSince
-				|| last_modified <= parseRFC822DateTimeString(ifModifiedSince);
+			const check = lastModifiedString == ifModifiedSince ||
+				last_modified <= parseRFC822DateTimeString(ifModifiedSince);
 			if (check) {
 				res.statusCode = HTTPStatus.notModified;
 				res.writeVoidBody();
@@ -572,9 +573,7 @@ struct ETag
 		enforce!ConvException(s.endsWith('"'));
 
 		if (s.startsWith(`W/"`)) {
-			ETag ret;
-			ret.weak = true;
-			ret.tag = s[3 .. $ - 1];
+			ETag ret = { weak: true, tag: s[3 .. $ - 1] };
 			return ret;
 		} else if (s.startsWith('"')) {
 			ETag ret;
@@ -602,30 +601,56 @@ bool cacheMatch(string match, ETag etag, bool allow_weak)
 		return true;
 	}
 
-	if (etag.weak && !allow_weak) {
+	if ((etag.weak && !allow_weak) || !match.length) {
 		return false;
 	}
 
-	size_t i = match.indexOf('"');
-	while (i != -1) {
-		size_t end = match.indexOf('"', i + 1);
-		if (end == -1) {
-			end = match.length;
-		}
+	auto allBytes = match.representation;
+
+	for (auto range = allBytes; !range.empty; range.popFront)
+	{
+		auto start = range = range.find('"').drop(1);
+		range = range.find('"');
+		if (range.empty)
+			break;
 
-		const check = match[i + 1 .. end];
-		const checkWeak = match[0 .. i].endsWith("W/");
+		const check = start[0 .. &range[0] - &start[0]];
+		const checkWeak = match[0 .. &start[0] - &allBytes[0]].endsWith(`W/"`);
 
 		if (allow_weak || !checkWeak) {
-			if (match[i + 1 .. end] == etag.tag) {
+			if (check == etag.tag) {
 				return true;
 			}
 		}
 
-		if (!match[end + 1 .. $].stripLeft.startsWith(","))
+		if (!(cast(string) range).stripLeft.startsWith(","))
 			break;
-		i = match.indexOf('"', end + 1);
 	}
 
 	return false;
 }
+
+unittest
+{
+	// from RFC 7232 Section 2.3.2
+	// +--------+--------+-------------------+-----------------+
+	// | ETag 1 | ETag 2 | Strong Comparison | Weak Comparison |
+	// +--------+--------+-------------------+-----------------+
+	// | W/"1"  | W/"1"  | no match          | match           |
+	// | W/"1"  | W/"2"  | no match          | no match        |
+	// | W/"1"  | "1"    | no match          | match           |
+	// | "1"    | "1"    | match             | match           |
+	// +--------+--------+-------------------+-----------------+
+
+	assert(!cacheMatch(`W/"1"`, ETag(true, "1"), false));
+	assert( cacheMatch(`W/"1"`, ETag(true, "1"), true));
+
+	assert(!cacheMatch(`W/"1"`, ETag(true, "2"), false));
+	assert(!cacheMatch(`W/"1"`, ETag(true, "2"), true));
+
+	assert(!cacheMatch(`W/"1"`, ETag(false, "1"), false));
+	assert( cacheMatch(`W/"1"`, ETag(false, "1"), true));
+
+	assert(cacheMatch(`"1"`, ETag(false, "1"), false));
+	assert(cacheMatch(`"1"`, ETag(false, "1"), true));
+}