1 files changed, 60 insertions, 0 deletions
diff --git a/runtime/lua/vim/termcap.lua b/runtime/lua/vim/termcap.lua
new file mode 100644
index 0000000000..0eefc5eee4
--- /dev/null
+++ b/runtime/lua/vim/termcap.lua
@@ -0,0 +1,60 @@
+local M = {}
+
+--- Query the host terminal emulator for terminfo capabilities.
+---
+--- This function sends the XTGETTCAP DCS sequence to the host terminal emulator asking the terminal
+--- to send us its terminal capabilities. These are strings that are normally taken from a terminfo
+--- file, however an up to date terminfo database is not always available (particularly on remote
+--- machines), and many terminals continue to misidentify themselves or do not provide their own
+--- terminfo file, making the terminfo database unreliable.
+---
+--- Querying the terminal guarantees that we get a truthful answer, but only if the host terminal
+--- emulator supports the XTGETTCAP sequence.
+---
+--- @param caps string|table A terminal capability or list of capabilities to query
+--- @param cb function(cap:string, seq:string) Function to call when a response is received
+function M.query(caps, cb)
+  vim.validate({
+    caps = { caps, { 'string', 'table' } },
+    cb = { cb, 'f' },
+  })
+
+  if type(caps) ~= 'table' then
+    caps = { caps }
+  end
+
+  local count = #caps
+
+  vim.api.nvim_create_autocmd('TermResponse', {
+    callback = function(args)
+      local resp = args.data ---@type string
+      local k, v = resp:match('^\027P1%+r(%x+)=(%x+)$')
+      if k and v then
+        local cap = vim.text.hexdecode(k)
+        local seq =
+          vim.text.hexdecode(v):gsub('\\E', '\027'):gsub('%%p%d', ''):gsub('\\(%d+)', string.char)
+
+        -- TODO: When libtermkey is patched to accept BEL as an OSC terminator, this workaround can
+        -- be removed
+        seq = seq:gsub('\007$', '\027\\')
+
+        cb(cap, seq)
+
+        count = count - 1
+        if count == 0 then
+          return true
+        end
+      end
+    end,
+  })
+
+  local encoded = {} ---@type string[]
+  for i = 1, #caps do
+    encoded[i] = vim.text.hexencode(caps[i])
+  end
+
+  local query = string.format('\027P+q%s\027\\', table.concat(encoded, ';'))
+  io.stdout:write(query)
+end
+
+return M