From cb3b8cce270aca0f1813bc71a647b282846f0ce9 Mon Sep 17 00:00:00 2001
From: Lars Viklund <zao@zao.se>
Date: Tue, 26 Mar 2024 22:50:45 +0100
Subject: [PATCH] fix: make file searches case-insensitive

As we moved from WinAPI `FindFirstFile` to `std::filesystem` path tests
and globbing was accidentally made case-sensitive as we use direct
string comparison or regular expressions to match files.

We now always construct a regular expression for the glob and make the
regex match case-insensitive. The regex is rebuilt on every file test
but as the set of files is likely to be small this is of low impact;
caching the regex in the search object would spread RE2 into the header.
---
 engine/system/win/sys_main.cpp | 52 +++++++++++++++++++++-------------
 1 file changed, 33 insertions(+), 19 deletions(-)

diff --git a/engine/system/win/sys_main.cpp b/engine/system/win/sys_main.cpp
index d929eca..fe03efc 100644
--- a/engine/system/win/sys_main.cpp
+++ b/engine/system/win/sys_main.cpp
@@ -145,29 +145,43 @@ bool GlobMatch(const std::filesystem::path& glob, const std::filesystem::path& f
 		return true;
 	}
 
-	// If no wildcards are present, test file path as-is.
+	fmt::memory_buffer buf;
+
+	// If no wildcards are present, test file path verbatim.
+	// We use a regex rather than string comparisons to make it case-insensitive.
 	if (globStr.find_first_of("?*") == std::string::npos) {
-		return glob == file;
+		buf.resize(globStr.size());
+		for (char ch : globStr) {
+			fmt::format_to(fmt::appender(buf), "[{}]", ch);
+		}
 	}
-
-	// Otherwise build a regular expression from the glob and use that to match files.
-	fmt::memory_buffer buf;
-	auto it = fmt::appender(buf);
-	for (char ch : glob.generic_string()) {
-		if (ch == '*') {
-			it = fmt::format_to(it, ".*");
-		} else if (ch == '?') {
-			*it++ = '.';
-		} else if ("+[]{}+()|"sv.find(ch) != std::string_view::npos) {
-			// Escape metacharacters
-			it = fmt::format_to(it, "\\{}", ch);
-		} else if (std::isalnum((unsigned char)ch)) {
-			*it++ = ch;
-		} else {
-			it = fmt::format_to(it, "[{}]", ch);
+	else {
+		// Otherwise build a regular expression from the glob and use that to match files.
+		auto it = fmt::appender(buf);
+		for (char ch : glob.generic_string()) {
+			if (ch == '*') {
+				it = fmt::format_to(it, ".*");
+			}
+			else if (ch == '?') {
+				*it++ = '.';
+			}
+			else if ("+[]{}+()|"sv.find(ch) != std::string_view::npos) {
+				// Escape metacharacters
+				it = fmt::format_to(it, "\\{}", ch);
+			}
+			else if (std::isalnum((unsigned char)ch)) {
+				*it++ = ch;
+			}
+			else {
+				it = fmt::format_to(it, "[{}]", ch);
+			}
 		}
 	}
-	RE2 reGlob{to_string(buf)};
+
+	// Assume case-insensitive comparisons are desired.
+	RE2::Options reOpts;
+	reOpts.set_case_sensitive(false);
+	RE2 reGlob{to_string(buf), reOpts};
 
 	return RE2::FullMatch(file.generic_string(), reGlob);
 }