From 1ca937518ed5ca00e18e5e59e1fef0d9bd628e16 Mon Sep 17 00:00:00 2001
From: khwerz <khwerz@gmail.com>
Date: Tue, 21 Jun 2022 00:01:14 -0400
Subject: simplify loop to sanitize filename and read extension

This uses gsub instead of find+sub. Also changes an ignoresuffix
pattern from /~$/ to /~+$/ which should reduce iterations.
---
 lua/plugins/filetype.lua | 50 ++++++++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 27 deletions(-)

diff --git a/lua/plugins/filetype.lua b/lua/plugins/filetype.lua
index 88ae9f2..b8640fc 100644
--- a/lua/plugins/filetype.lua
+++ b/lua/plugins/filetype.lua
@@ -1,7 +1,7 @@
 vis.ftdetect = {}
 
 vis.ftdetect.ignoresuffixes = {
-	"~$", "%.orig$", "%.bak$", "%.old$", "%.new$"
+	"~+$", "%.orig$", "%.bak$", "%.old$", "%.new$"
 }
 
 vis.ftdetect.filetypes = {
@@ -484,39 +484,35 @@ vis.events.subscribe(vis.events.WIN_OPEN, function(win)
 		win:set_syntax(syntax)
 	end
 
-	local name = win.file.name
-	-- remove ignored suffixes from filename
-	local sanitizedfn = name
-	if sanitizedfn ~= nil then
-		sanitizedfn = sanitizedfn:gsub('^.*/', '')
-		repeat
-			local changed = false
-			for _, pattern in pairs(vis.ftdetect.ignoresuffixes) do
-				local start = sanitizedfn:find(pattern)
-				if start then
-					sanitizedfn = sanitizedfn:sub(1, start-1)
-					changed = true
+	local path = win.file.name -- filepath
+	local mime
+
+	if path and #path > 0 then
+		local name = path:match("[^/]+") -- filename
+		if name then
+			local unchanged
+			while #name > 0 and name ~= unchanged do
+				unchanged = name
+				for _, pattern in ipairs(vis.ftdetect.ignoresuffixes) do
+					name = name:gsub(pattern, "")
 				end
 			end
-		until not changed
-	end
+		end
 
-	-- detect filetype by filename ending with a configured extension
-	if sanitizedfn ~= nil then
-		for lang, ft in pairs(vis.ftdetect.filetypes) do
-			for _, pattern in pairs(ft.ext or {}) do
-				if sanitizedfn:match(pattern) then
-					set_filetype(lang, ft)
-					return
+		if name and #name > 0 then
+			-- detect filetype by filename ending with a configured extension
+			for lang, ft in pairs(vis.ftdetect.filetypes) do
+				for _, pattern in pairs(ft.ext or {}) do
+					if name:match(pattern) then
+						set_filetype(lang, ft)
+						return
+					end
 				end
 			end
 		end
-	end
 
-	-- run file(1) to determine mime type
-	local mime
-	if name ~= nil then
-		local file = io.popen(string.format("file -bL --mime-type -- '%s'", name:gsub("'", "'\\''")))
+		-- run file(1) to determine mime type
+		local file = io.popen(string.format("file -bL --mime-type -- '%s'", path:gsub("'", "'\\''")))
 		if file then
 			mime = file:read('*all')
 			file:close()
-- 
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