refactor parser to more idiomatic OOP

1 files changed, 34 insertions, 33 deletions

diff --git a/parser.lua b/parser.lua
index 99b16db..c0b9e85 100644
--- a/parser.lua
+++ b/parser.lua
@@ -1,4 +1,4 @@
--- Copyright (c) 2021 Florian Fischer. All rights reserved.
+-- Copyright (c) 2021-2024 Florian Fischer. All rights reserved.
 --
 -- This file is part of vis-lspc.
 --
@@ -18,14 +18,26 @@
 -- Note the chunks received may not end with the end of a message.
 -- In the worst case a data chunk contains two partial messages on at the beginning
 -- and one at the end
-local function add(p, data)
-  p.data = p.data .. data
+--- @module parser
+local parser = {}
+
+local Parser = {}
+
+function parser.new()
+  local self = {exp_len = nil, data = '', msgs = {}}
+
+  setmetatable(self, {__index = Parser})
+  return self
+end
+
+function Parser:add(data)
+  self.data = self.data .. data
 
   -- we have not seen a complete header in data yet
-  if not p.exp_len then
+  if not self.exp_len then
     -- search for the end of a header
     -- LSP message format: 'header\r\n\r\nbody'
-    local header_end, content_start = p.data:find('\r\n\r\n')
+    local header_end, content_start = self.data:find('\r\n\r\n')
 
     -- header is not complete yet -> save data and wait for more
     if not header_end then
@@ -33,55 +45,44 @@ local function add(p, data)
     end
 
     -- got a complete header
-    local header = p.data:sub(1, header_end)
+    local header = self.data:sub(1, header_end)
 
     -- extract content length from the header
-    p.exp_len = tonumber(header:match('%d+'))
-    if not p.exp_len then
-      return 'invalid header in data: ' .. p.data
+    self.exp_len = tonumber(header:match('%d+'))
+    if not self.exp_len then
+      return 'invalid header in data: ' .. self.data
     end
 
     -- consume header from data
-    p.data = p.data:sub(content_start + 1)
+    self.data = self.data:sub(content_start + 1)
   end
 
-  local data_avail = string.len(p.data)
+  local data_avail = string.len(self.data)
   -- we have no complete message yet -> await more data
-  if p.exp_len > data_avail then
+  if self.exp_len > data_avail then
     return
   end
 
-  local complete_msg = p.data:sub(1, p.exp_len)
-  table.insert(p.msgs, complete_msg)
+  local complete_msg = self.data:sub(1, self.exp_len)
+  table.insert(self.msgs, complete_msg)
 
   -- consume complete_msg from data
-  p.data = p.data:sub(p.exp_len + 1)
+  self.data = self.data:sub(self.exp_len + 1)
 
-  local leftover = data_avail - p.exp_len
+  local leftover = data_avail - self.exp_len
 
   -- reset exp_len to search for a new header
-  p.exp_len = nil
+  self.exp_len = nil
 
   if leftover > 0 then
-    return p:add('')
+    return self:add('')
   end
 end
 
-local function get_msgs(p)
-  local msgs = p.msgs
-  p.msgs = {}
+function Parser:get_msgs()
+  local msgs = self.msgs
+  self.msgs = {}
   return msgs
 end
 
-local function Parser()
-  local parser = {
-    add = add,
-    get_msgs = get_msgs,
-    exp_len = nil,
-    data = '',
-    msgs = {},
-  }
-  return parser
-end
-
-return {Parser = Parser}
+return parser