From 0776200bf5c132a3b24a83ff2346bead3362a652 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Sun, 14 Feb 2021 17:43:59 +0100
Subject: initial commit

---
 init.lua | 645 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 645 insertions(+)
 create mode 100644 init.lua

(limited to 'init.lua')

diff --git a/init.lua b/init.lua
new file mode 100644
index 0000000..59f0098
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,645 @@
+-- Copyright (c) 2021 Florian Fischer. All rights reserved.
+-- Use of this source code is governed by a MIT license found in the LICENSE file.
+-- We require vis compiled with the communicate patch
+if not vis.communicate then
+  vis:info('Error: language server support requires vis communicate patch')
+  return nil
+end
+
+local function load_fallback_json()
+  local source_str = debug.getinfo(1, 'S').source:sub(2)
+  local script_path = source_str:match('(.*/)')
+
+  return dofile(script_path .. 'json.lua')
+end
+
+-- find a suitable json implementation
+local json
+if vis:module_exist('json') then
+  json = require('json')
+  if not json.encode or not json.decode then
+    json = load_fallback_json()
+  end
+else
+  json = load_fallback_json()
+end
+
+-- get vis's pid to pass it to the language servers
+local vis_proc_file = assert(io.open('/proc/self/stat', 'r'))
+local vis_pid = vis_proc_file:read('*n')
+vis_proc_file:close()
+
+-- forward declaration of our client table
+local lspc
+
+-- logging system
+-- if lspc.logging is set to true the first call to lspc.log
+-- will open the log file and replace lspc.log with the actual log function
+local init_logging
+do
+  local log_fd
+  local function log(msg)
+    log_fd:write(msg)
+    log_fd:flush()
+  end
+
+  init_logging = function(msg)
+    if not lspc.logging then
+      return
+    end
+
+    log_fd = assert(io.open('vis-lspc.log', 'w'))
+    lspc.log = log
+
+    log(msg)
+  end
+end
+
+
+-- state of our language server client
+lspc = {
+  running = {},
+  name = 'vis-lspc',
+  version = '0.0.1',
+  logging = true,
+  log = init_logging,
+}
+
+local clangd = {name = 'clangd', cmd = 'clangd'}
+
+-- map of known language servers per syntax
+lspc.ls_map = {cpp = clangd, ansi_c = clangd}
+
+-- Document position code
+-- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocumentPositionParams
+
+-- A document positions is defined by a file path and a (line, column) tuple
+-- We use 1-based indices like vis and lua.
+-- Note line and col numbers must be transformed into 0-based inices when communicating
+-- with a language server
+
+local function path_to_uri(path)
+  return 'file://' .. path
+end
+
+-- uri decode logic taken from
+-- https://stackoverflow.com/questions/20405985/lua-decodeuri-luvit
+local uri_decode_table = {}
+for i = 0, 255 do
+  uri_decode_table[string.format('%02x', i)] = string.char(i)
+  uri_decode_table[string.format('%02X', i)] = string.char(i)
+end
+
+local function decode_uri(s)
+  return (s:gsub('%%(%x%x)', uri_decode_table))
+end
+
+local function uri_to_path(uri)
+  return decode_uri(uri:gsub('file://', ''))
+end
+
+-- convert LSP 0-based Position to vis position
+local function lsp_pos_to_vis(pos)
+  return {line = pos.line + 1, col = pos.character + 1}
+end
+
+-- convert 1-based vis position to LSP Position
+local function vis_pos_to_lsp(pos)
+  return {line = pos.line - 1, character = pos.col - 1}
+end
+
+-- convert our doc_pos to LSP TextDocumentPosition
+local function vis_doc_pos_to_lsp(doc_pos)
+  return {
+    textDocument = {uri = path_to_uri(doc_pos.file)},
+    position = vis_pos_to_lsp({line = doc_pos.line, col = doc_pos.col}),
+  }
+end
+
+-- convert LSP TextDocumentPosition to our doc_pos
+local function lsp_doc_pos_to_vis(doc_pos)
+  local pos = lsp_pos_to_vis(doc_pos.position)
+  return {
+    file = uri_to_path(doc_pos.textDocument.uri),
+    line = pos.line,
+    col = pos.col,
+  }
+end
+
+-- get document position of the main curser
+local function vis_get_doc_pos(win)
+  win = win or vis.win
+  return {
+    file = win.file.path,
+    line = win.selection.line,
+    col = win.selection.col,
+  }
+end
+
+-- Support jumping between document positions
+-- Open a document position in the active window
+local vis_push_doc_pos
+-- Restore the last text position in the active window
+local vis_pop_doc_pos
+do
+  -- stack of edited document positions
+  local doc_pos_stack = {}
+
+  local function vis_goto_doc_pos(doc_pos)
+    vis:command('e ' .. doc_pos.file)
+    vis.win.selection:to(doc_pos.line, doc_pos.col)
+  end
+
+  vis_push_doc_pos = function(doc_pos)
+    local old_doc_pos = {}
+    old_doc_pos.file = vis.win.file.path
+    old_doc_pos.line = vis.win.selection.line
+    old_doc_pos.col = vis.win.selection.col
+
+    table.insert(doc_pos_stack, old_doc_pos)
+    vis_goto_doc_pos(doc_pos)
+  end
+
+  vis_pop_doc_pos = function()
+    local last_doc_pos = table.remove(doc_pos_stack)
+    if not last_doc_pos then
+      return
+    end
+    vis_goto_doc_pos(last_doc_pos)
+
+    -- reopen possibly closed file
+    vis:command('lspc-open')
+  end
+end
+
+vis:command_register('lspc-back', function()
+  vis_pop_doc_pos()
+end)
+
+-- apply a textEdit received from the language server
+local function vis_apply_textEdit(win, file, textEdit)
+  assert(win.file == file)
+
+  local start_pos = lsp_pos_to_vis(textEdit.range.start)
+  local end_pos = lsp_pos_to_vis(textEdit.range['end'])
+
+  -- convert the LSP range into a vis range
+  -- this destroys the current selection but we change it after the edit anyway
+  win.selection.anchored = false
+  win.selection:to(start_pos.line, start_pos.col)
+  win.selection.anchored = true
+  win.selection:to(end_pos.line, end_pos.col - 1)
+  local range = win.selection.range
+
+  file:delete(range)
+  file:insert(range.start, textEdit.newText)
+
+  win.selection.anchored = false
+  win.selection.pos = range.start + string.len(textEdit.newText)
+
+  win:draw()
+end
+
+-- send a rpc message to a language server
+local function ls_rpc(ls, req)
+  req.jsonrpc = '2.0'
+
+  local content_part = json.encode(req)
+  local content_len = string.len(content_part)
+
+  local header_part = 'Content-Length: ' .. tostring(content_len)
+  local msg = header_part .. '\r\n\r\n' .. content_part
+  lspc.log('LSPC Sending: ' .. msg .. '\n')
+
+  ls.fd:write(msg)
+  ls.fd:flush()
+end
+
+-- send a rpc method call to a language server
+local function ls_call_method(ls, method, params, win)
+  local id = ls.id
+  ls.id = ls.id + 1
+
+  local req = {id = id, method = method, params = params}
+  ls.inflight[id] = req
+
+  ls_rpc(ls, req)
+  -- remember the current window to apply the effects of a
+  -- method call in the original window
+  ls.inflight[id].win = win
+end
+
+-- send a rpc notification to a language server
+local function ls_send_notification(ls, method, params)
+  ls_rpc(ls, {method = method, params = params})
+end
+
+local function lspc_handle_goto_method_response(method, result)
+  if not result or next(result) == nil then
+    vis:info('LSPC Warning: ' .. method .. ' found no results')
+    return
+  end
+
+  local location
+  -- result is no plain Location -> it must be Location[]
+  if not result.uri then
+    -- Use the first result. TODO: smarter result selection
+    location = result[1]
+  else
+    location = result
+  end
+  assert(location)
+
+  local lsp_doc_pos = {
+    textDocument = {uri = location.uri},
+    position = {
+      line = location.range.start.line,
+      character = location.range.start.character,
+    },
+  }
+
+  vis_push_doc_pos(lsp_doc_pos_to_vis(lsp_doc_pos))
+end
+
+local function lspc_handle_completion_method_response(win, result)
+  if not result or not result.items then
+    vis:info('LSPC Warning: no completion available')
+    return
+  end
+
+  local completions = result
+  if result.isIncomplete ~= nil then
+    completions = result.items
+  end
+
+  local vis_menu_input = ''
+  for _, completion in ipairs(completions) do
+    vis_menu_input = vis_menu_input .. completion.label .. '\n'
+  end
+
+  -- select a completion
+  local completion = nil
+  local cmd = 'printf "' .. vis_menu_input .. '" | vis-menu'
+  local status, selection = vis:pipe(win.file, {start = 0, finish = 0}, cmd)
+  if status == 0 then
+    -- trim newline from selection
+    selection = selection:sub(1, -2)
+
+    for _, item in ipairs(completions) do
+      if selection == item.label then
+        completion = item
+        break
+      end
+    end
+
+    assert(completion)
+
+    vis_apply_textEdit(win, win.file, completion.textEdit)
+  end
+end
+
+-- method response dispatcher
+local function ls_handle_method_response(ls, method_response)
+  local req = assert(ls.inflight[method_response.id])
+  local win = req.win
+
+  local method = req.method
+  local result = method_response.result
+  -- LuaFormatter off
+  if method == 'textDocument/definition' or
+     method == 'textDocument/declaration' or
+     method == 'textDocument/typeDefinition' or
+     method == 'textDocument/implementation' then
+    -- LuaFormatter on
+    lspc_handle_goto_method_response(method, result)
+
+  elseif method == 'initialize' then
+    ls.initialized = true
+    ls.capabilities = result.capabilities
+    ls_send_notification(ls, 'initialized')
+
+  elseif method == 'textDocument/completion' then
+    lspc_handle_completion_method_response(win, result)
+
+  elseif method == 'shutdown' then
+    ls_send_notification(ls, 'exit')
+    ls.fd:close()
+
+    -- remove the ls from lspc.running
+    for syntax, rls in pairs(lspc.running) do
+      if ls == rls then
+        lspc.running[syntax] = nil
+        break
+      end
+    end
+  else
+    vis:info('Warning: received unknown method ' .. method)
+  end
+
+  ls.inflight[method_response.id] = nil
+end
+
+local function ls_handle_notification(ls, notification) -- luacheck: no unused args
+end
+
+-- dispatch between a method response and a notification from the server
+local function ls_handle_msg(ls, response)
+  if response.id then
+    ls_handle_method_response(ls, response)
+  else
+    ls_handle_notification(ls, response)
+  end
+end
+
+-- Parse the data send by the 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 on at the beginning
+-- and one at the end
+local function ls_recv_data(ls, data)
+  -- new message received
+  if ls.partial_response.len == 0 then
+    lspc.log('LSPC: parse new message')
+    local header = data:match('^Content%-Length: %d+')
+    ls.partial_response.exp_len = tonumber(header:match('%d+'))
+    local _, content_start = data:find('\r\n\r\n')
+
+    ls.partial_response.msg = data:sub(content_start + 1)
+    ls.partial_response.len = string.len(ls.partial_response.msg)
+
+  else -- try to complete partial received message
+    lspc.log('LSPC: parse message continuation')
+    ls.partial_response.msg = ls.partial_response.msg .. data
+    ls.partial_response.len = ls.partial_response.len + string.len(data)
+  end
+
+  -- received message not complete yet
+  if ls.partial_response.len < ls.partial_response.exp_len then
+    return
+  end
+
+  local complete_msg = ls.partial_response.msg:sub(1,
+                                                   ls.partial_response.exp_len)
+
+  lspc.log('LSPC: handling complete message:\n' .. complete_msg .. '\n')
+  local resp = json.decode(complete_msg)
+  ls_handle_msg(ls, resp)
+
+  local leftover = ls.partial_response.len - ls.partial_response.exp_len
+
+  if leftover > 0 then
+    local leftover_data = ls.partial_response.msg:sub(
+                              ls.partial_response.exp_len + 1)
+    lspc.log('LSPC: parse leftover:\n"' .. leftover_data .. '"\n')
+
+    ls.partial_response.exp_len = 0
+    ls.partial_response.len = 0
+    ls_recv_data(ls, leftover_data)
+  end
+
+  ls.partial_response.exp_len = 0
+  ls.partial_response.len = 0
+end
+
+-- check if a language server is running and register file as open
+local function lspc_get_usable_ls(syntax)
+  local ls = lspc.running[syntax]
+  if not ls then
+    vis:info('Error: No language server running for ' .. syntax)
+    return nil
+  end
+
+  if not ls.initialized then
+    vis:info('Error: Language server not initialized yet. Please try again')
+    return nil
+  end
+
+  return ls
+end
+
+local function lspc_close(ls, file)
+  ls_send_notification(ls, 'textDocument/didClose',
+                       {textDocument = {uri = path_to_uri(file.path)}})
+  ls.open_files[file.path] = nil
+end
+
+vis:command_register('lspc-close', function(_, _, win)
+  local ls = lspc_get_usable_ls(win.syntax)
+
+  lspc_close(ls, win.file)
+end)
+
+-- register a file as open with a language server and setup a close and save event handlers
+-- A file must be opened before any textDocument functions can be used with it.
+local function lspc_open(ls, win, file)
+  local params = {
+    textDocument = {
+      uri = 'file://' .. file.path,
+      languageId = win.syntax,
+      version = 0,
+      text = file:content(0, file.size),
+    },
+  }
+
+  ls.open_files[file.path] = {file = file, version = 0}
+  ls_send_notification(ls, 'textDocument/didOpen', params)
+
+  -- TODO: implement textDocument/didChange
+
+  vis.events.subscribe(vis.events.FILE_CLOSE, function(file)
+    for _, ls in pairs(lspc.running) do
+      if ls.open_files[file.path] then
+        lspc_close(ls, file)
+      end
+    end
+  end)
+
+  -- the server is interested in didSave notifications
+  if ls.capabilities.textDocumentSync.save then
+    vis.events.subscribe(vis.events.FILE_SAVE_POST, function(file, path)
+      for _, ls in pairs(lspc.running) do
+        if ls.open_files[file.path] then
+          local params = {textDocument = {uri = path_to_uri(path)}}
+          ls_send_notification(ls, 'textDocument/didSave', params)
+        end
+      end
+    end)
+  end
+
+end
+
+vis:command_register('lspc-open', function(_, _, win)
+  local ls = lspc_get_usable_ls(win.syntax)
+
+  if ls.open_files[win.file.path] then
+    return
+  end
+
+  lspc_open(ls, win, win.file)
+end)
+
+-- Initiate the shutdown of a language server
+-- Sending the exit notification and closing the file handle are done in
+-- the shutdown response handler.
+local function ls_shutdown_server(ls)
+  ls_call_method(ls, 'shutdown', nil)
+end
+
+vis:command_register('lspc-shutdown-server', function(argv, _, win)
+  local ls = lspc_get_usable_ls(argv[1] or win.syntax)
+  if not ls then
+    return
+  end
+
+  ls_shutdown_server(ls)
+end)
+
+local function ls_start_server(syntax)
+  if lspc.running[syntax] then
+    vis:info('Error: Already a language server running for ' .. syntax)
+    return
+  end
+
+  local ls_conf = lspc.ls_map[syntax]
+  if not ls_conf then
+    vis:info('Error: No language server available for ' .. syntax)
+    return
+  end
+
+  local ls = {
+    name = ls_conf.name,
+    initialized = false,
+    id = 0,
+    inflight = {},
+    open_files = {},
+    partial_response = {exp_len = 0, len = 0, response = nil},
+  }
+
+  ls.fd = vis:communicate(ls_conf.name, ls_conf.cmd)
+
+  lspc.running[syntax] = ls
+
+  -- register the response handler
+  vis.events.subscribe(vis.events.PROCESS_RESPONSE, function(name, msg, event)
+    if name ~= ls.name then
+      return
+    end
+
+    if event == 'EXIT' or event == 'SIGNAL' then
+      if event == 'EXIT' then
+        vis:info('language server exited with: ' .. msg)
+      else
+        vis:info('language server received signal: ' .. msg)
+      end
+
+      ls.running[syntax] = nil
+      return
+    end
+
+    lspc.log('LS response(' .. event .. '): ' .. msg .. '\n')
+    if event == 'STDERR' then
+      return
+    end
+
+    ls_recv_data(ls, msg)
+  end)
+
+  local params = {
+    processID = vis_pid,
+    client = {name = lspc.name, version = lspc.version},
+    rootUri = nil,
+    capabilities = {},
+  }
+
+  ls_call_method(ls, 'initialize', params)
+
+  return ls
+end
+
+vis:command_register('lspc-start-server', function(argv, _, win)
+  ls_start_server(argv[1] or win.syntax)
+end)
+
+local function lspc_method_textDocumentPositionParams(ls, method, win)
+  -- check if the language server has a provider for this method
+  if not ls.capabilities[method .. 'Provider'] then
+    vis:info(
+        'LPSC Error: language server ' .. ls.name .. ' does not provide ' ..
+            method)
+    return
+  end
+
+  if not ls.open_files[win.file.path] then
+    lspc_open(ls, win, win.file)
+  end
+
+  local params = vis_doc_pos_to_lsp(vis_get_doc_pos(win))
+
+  ls_call_method(ls, 'textDocument/' .. method, params, win)
+end
+
+local function lspc_declaration(ls, win)
+  lspc_method_textDocumentPositionParams(ls, 'declaration', win)
+end
+
+local function lspc_definition(ls, win)
+  lspc_method_textDocumentPositionParams(ls, 'definition', win)
+end
+
+local function lspc_typeDefinition(ls, win)
+  lspc_method_textDocumentPositionParams(ls, 'typeDefinition', win)
+end
+
+local function lspc_implementation(ls, win)
+  lspc_method_textDocumentPositionParams(ls, 'implementation', win)
+end
+
+local function lspc_completion(ls, win)
+  lspc_method_textDocumentPositionParams(ls, 'completion', win)
+end
+
+local lspc_methods = {
+  declaration = lspc_declaration,
+  definition = lspc_definition,
+  typeDefinition = lspc_typeDefinition,
+  implementation = lspc_implementation,
+  completion = lspc_completion,
+}
+
+for name, func in pairs(lspc_methods) do
+  vis:command_register('lspc-' .. name, function(_, _, win, selection)
+    local ls = lspc_get_usable_ls(win.syntax, win.file)
+    if not ls then
+      return
+    end
+
+    func(ls, win, selection)
+  end)
+end
+
+-- default bindings
+vis:map(vis.modes.NORMAL, '<F2>', function()
+  vis:command('lspc-start-server')
+end)
+
+vis:map(vis.modes.NORMAL, '<F3>', function()
+  vis:command('lspc-open')
+end)
+
+vis:map(vis.modes.NORMAL, '<C-]>', function()
+  vis:command('lspc-definition')
+end)
+
+vis:map(vis.modes.NORMAL, '<C-t>', function()
+  vis:command('lspc-back')
+end)
+
+vis:map(vis.modes.NORMAL, '<C- >', function()
+  vis:command('lspc-completion')
+end)
+
+vis:map(vis.modes.INSERT, '<C- >', function()
+  vis:command('lspc-completion')
+  vis.mode = vis.modes.INSERT
+end)
+
+return lspc
-- 
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