1 files changed, 76 insertions, 0 deletions
diff --git a/.config/vis/plugins/vis-lspc/parser.lua b/.config/vis/plugins/vis-lspc/parser.lua
new file mode 100644
index 0000000..0c9fc0a
--- /dev/null
+++ b/.config/vis/plugins/vis-lspc/parser.lua
@@ -0,0 +1,76 @@
+--- Stateful parser for the data send by a language server.
+-- Note the chunks received may not end with the end of a message.
+-- In the worst case a data chunk contains two partial messages one
+-- at the beginning and one at the end.
+-- @module parser
+-- @author Florian Fischer
+-- @license GPL-3
+-- @copyright Florian Fischer 2021-2024
+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 self.exp_len then
+    -- search for the end of a header
+    -- LSP message format: header\r\n(header\r\n)?\r\nbody'
+    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
+      return
+    end
+
+    -- got a complete header
+    local header = self.data:sub(1, header_end)
+
+    -- extract content length from the header
+    local length = header:match('Content%-Length: %d+')
+    self.exp_len = tonumber(length:match('%d+'))
+    if not self.exp_len then
+      return 'invalid header in data: ' .. self.data
+    end
+
+    -- consume header from data
+    self.data = self.data:sub(content_start + 1)
+  end
+
+  local data_avail = string.len(self.data)
+  -- we have no complete message yet -> await more data
+  if self.exp_len > data_avail then
+    return
+  end
+
+  local complete_msg = self.data:sub(1, self.exp_len)
+  table.insert(self.msgs, complete_msg)
+
+  -- consume complete_msg from data
+  self.data = self.data:sub(self.exp_len + 1)
+
+  local leftover = data_avail - self.exp_len
+
+  -- reset exp_len to search for a new header
+  self.exp_len = nil
+
+  if leftover > 0 then
+    return self:add('')
+  end
+end
+
+function Parser:get_msgs()
+  local msgs = self.msgs
+  self.msgs = {}
+  return msgs
+end
+
+return parser