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-- Converted into Lua from https://github.com/cyjake/ssh-config
-- TODO (siddhantdev): deal with include directives
local M = {}
local whitespace_pattern = '%s'
local line_break_pattern = '[\r\n]'
---@param param string
local function is_multi_value_directive(param)
local multi_value_directives = {
'globalknownhostsfile',
'host',
'ipqos',
'sendenv',
'userknownhostsfile',
'proxycommand',
'match',
'canonicaldomains',
}
return vim.list_contains(multi_value_directives, param:lower())
end
---@param text string The ssh configuration which needs to be parsed
---@return string[] The parsed host names in the configuration
function M.parse_ssh_config(text)
local i = 1
local line = 1
local function consume()
if i <= #text then
local char = text:sub(i, i)
i = i + 1
return char
end
return nil
end
local chr = consume()
local function parse_spaces()
local spaces = ''
while chr and chr:match(whitespace_pattern) do
spaces = spaces .. chr
chr = consume()
end
return spaces
end
local function parse_linebreaks()
local breaks = ''
while chr and chr:match(line_break_pattern) do
line = line + 1
breaks = breaks .. chr
chr = consume()
end
return breaks
end
local function parse_parameter_name()
local param = ''
while chr and not chr:match('[ \t=]') do
param = param .. chr
chr = consume()
end
return param
end
local function parse_separator()
local sep = parse_spaces()
if chr == '=' then
sep = sep .. chr
chr = consume()
end
return sep .. parse_spaces()
end
local function parse_value()
local val = {}
local quoted, escaped = false, false
while chr and not chr:match(line_break_pattern) do
if escaped then
table.insert(val, chr == '"' and chr or '\\' .. chr)
escaped = false
elseif chr == '"' and (val == {} or quoted) then
quoted = not quoted
elseif chr == '\\' then
escaped = true
elseif chr == '#' and not quoted then
break
else
table.insert(val, chr)
end
chr = consume()
end
if quoted or escaped then
error('Unexpected line break at line ' .. line)
end
return vim.trim(table.concat(val))
end
local function parse_comment()
while chr and not chr:match(line_break_pattern) do
chr = consume()
end
end
---@return string[]
local function parse_multiple_values()
local results = {}
local val = {}
local quoted = false
local escaped = false
while chr and not chr:match(line_break_pattern) do
if escaped then
table.insert(val, chr == '"' and chr or '\\' .. chr)
escaped = false
elseif chr == '"' then
quoted = not quoted
elseif chr == '\\' then
escaped = true
elseif quoted then
table.insert(val, chr)
elseif chr:match('[ \t=]') then
if val ~= {} then
table.insert(results, vim.trim(table.concat(val)))
val = {}
end
elseif chr == '#' and #results > 0 then
break
else
table.insert(val, chr)
end
chr = consume()
end
if quoted or escaped then
error('Unexpected line break at line ' .. line)
end
if val ~= {} then
table.insert(results, vim.trim(table.concat(val)))
end
return results
end
local function parse_directive()
local param = parse_parameter_name()
local multiple = is_multi_value_directive(param)
local _ = parse_separator()
local value = multiple and parse_multiple_values() or parse_value()
local result = {
param = param,
value = value,
}
return result
end
local function parse_line()
local _ = parse_spaces()
if chr == '#' then
parse_comment()
return nil
end
local node = parse_directive()
local _ = parse_linebreaks()
return node
end
local hostnames = {}
---@param value string
local function is_valid(value)
return not (value:find('[?*!]') or vim.list_contains(hostnames, value))
end
while chr do
local node = parse_line()
if node then
-- This is done just to assign the type
node.value = node.value ---@type string[]
if node.param:lower() == 'match' and node.value then
local current = nil
for ind, val in ipairs(node.value) do
if val:lower() == 'host' and ind + 1 <= #node.value and is_valid(node.value[ind + 1]) then
current = node.value[ind + 1]
end
end
if current then
table.insert(hostnames, current)
end
elseif node.param:lower() == 'host' and node.value then
for _, value in ipairs(node.value) do
if is_valid(value) then
table.insert(hostnames, value)
end
end
end
end
end
return hostnames
end
---@param filename string
---@return string[] The hostnames configured in the file located at filename
function M.parse_config(filename)
local file = io.open(filename, 'r')
if not file then
error('Cannot read ssh configuration file')
end
local config_string = file:read('*a')
file:close()
return M.parse_ssh_config(config_string)
end
---@return string[] The hostnames configured in the ssh configuration file
--- located at "~/.ssh/config".
--- Note: This does not currently process `Include` directives in the
--- configuration file.
function M.get_hosts()
local config_path = vim.fs.normalize('~/.ssh/config') ---@type string
return M.parse_config(config_path)
end
return M
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