lsp_windowing.lua

--[[
Code in this file was originally taken from neovim's
source code. (Specifically
https://github.com/neovim/neovim/tree/v0.7.2)  As
such this code follows neovim's license.

Note, the original code taken from neovim's
source did not appear to be from vim's original source
so it should not be subject to vim's license.

Copyright Neovim contributors. All rights reserved.

Neovim is licensed under the terms of the Apache 2.0 license, except for
parts of Neovim that were contributed under the Vim license (see below).

Neovim's license follows:

====
                                 Apache License
                           Version 2.0, January 2004
                        https://www.apache.org/licenses/

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====

The above license applies to all parts of Neovim except (1) parts that were
contributed under the Vim license and (2) externally maintained libraries.

The externally maintained libraries used by Neovim are:

  - Klib: a Generic Library in C. MIT/X11 license.
  - Lua: MIT license
  - LuaJIT: a Just-In-Time Compiler for Lua. Copyright Mike Pall. MIT license.
  - Luv: Apache 2.0 license
  - libmpack: MIT license
  - libtermkey: MIT license
  - libuv. Copyright Joyent, Inc. and other Node contributors. Node.js license.
  - libvterm: MIT license
  - lua-cjson: MIT license
  - lua-compat: MIT license
  - tree-sitter: MIT license
  - unibilium: LGPL v3
  - xdiff: LGPL v2

====

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those contributions under the Apache 2.0 license.

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--]]

local function str_byteindex_enc(line, index, encoding)
  if not encoding then encoding = 'utf-16' end
  if encoding == 'utf-8' then
    if index then return index else return #line end
  elseif encoding == 'utf-16' then
    return vim.str_byteindex(line, index, true)
  elseif encoding == 'utf-32' then
    return vim.str_byteindex(line, index)
  else
    error("Invalid encoding: " .. vim.inspect(encoding))
  end
end

local function get_lines(bufnr, rows)
  rows = type(rows) == "table" and rows or { rows }

  -- This is needed for bufload and bufloaded
  if bufnr == 0 then
    bufnr = vim.api.nvim_get_current_buf()
  end

  ---@private
  local function buf_lines()
    local lines = {}
    for _, row in pairs(rows) do
      lines[row] = (vim.api.nvim_buf_get_lines(bufnr, row, row + 1, false) or { "" })[1]
    end
    return lines
  end

  local uri = vim.uri_from_bufnr(bufnr)

  -- load the buffer if this is not a file uri
  -- Custom language server protocol extensions can result in servers sending URIs with custom schemes. Plugins are able to load these via `BufReadCmd` autocmds.
  if uri:sub(1, 4) ~= "file" then
    vim.fn.bufload(bufnr)
    return buf_lines()
  end

  -- use loaded buffers if available
  if vim.fn.bufloaded(bufnr) == 1 then
    return buf_lines()
  end

  local filename = api.nvim_buf_get_name(bufnr)

  -- get the data from the file
  local fd = uv.fs_open(filename, "r", 438)
  if not fd then return "" end
  local stat = uv.fs_fstat(fd)
  local data = uv.fs_read(fd, stat.size, 0)
  uv.fs_close(fd)

  local lines = {} -- rows we need to retrieve
  local need = 0 -- keep track of how many unique rows we need
  for _, row in pairs(rows) do
    if not lines[row] then
      need = need + 1
    end
    lines[row] = true
  end

  local found = 0
  local lnum = 0

  for line in string.gmatch(data, "([^\n]*)\n?") do
    if lines[lnum] == true then
      lines[lnum] = line
      found = found + 1
      if found == need then break end
    end
    lnum = lnum + 1
  end

  -- change any lines we didn't find to the empty string
  for i, line in pairs(lines) do
    if line == true then
      lines[i] = ""
    end
  end
  return lines
end

local function get_line(bufnr, row)
  return get_lines(bufnr, { row })[row]
end

local function get_line_byte_from_position(bufnr, position, offset_encoding)
  -- LSP's line and characters are 0-indexed
  -- Vim's line and columns are 1-indexed
  local col = position.character
  -- When on the first character, we can ignore the difference between byte and
  -- character
  if col > 0 then
    local line = get_line(bufnr, position.line) or ''
    local ok, result
    ok, result = pcall(str_byteindex_enc, line, col, offset_encoding)
    if ok then
      return result
    end
    return math.min(#line, col)
  end
  return col
end

local function jump_to_location(location, offset_encoding)
  -- location may be Location or LocationLink
  local uri = location.uri or location.targetUri
  if uri == nil then return end
  if offset_encoding == nil then
    vim.notify_once("jump_to_location must be called with valid offset encoding", vim.log.levels.WARN)
  end
  local bufnr = vim.uri_to_bufnr(uri)
  -- Save position in jumplist
  vim.cmd "normal! m'"

  -- Push a new item into tagstack
  local from = {vim.fn.bufnr('%'), vim.fn.line('.'), vim.fn.col('.'), 0}
  local items = {{tagname=vim.fn.expand('<cword>'), from=from}}
  vim.fn.settagstack(vim.fn.win_getid(), {items=items}, 't')

  --- Jump to new location (adjusting for UTF-16 encoding of characters)
  if vim.api.nvim_win_get_number(vim.api.nvim_get_current_win()) < 2
  then
    vim.cmd('vsplit')
  else
    vim.cmd('split')
  end

  local win = vim.api.nvim_get_current_win()
  local buf = vim.api.nvim_create_buf(true, true)
  vim.api.nvim_set_current_buf(bufnr)
  vim.api.nvim_buf_set_option(bufnr, 'buflisted', true)
  local range = location.range or location.targetSelectionRange
  local row = range.start.line
  local col = get_line_byte_from_position(bufnr, range.start, offset_encoding)
  vim.api.nvim_win_set_cursor(0, {row + 1, col})
  -- Open folds under the cursor
  vim.cmd("normal! zv")
  return true
end

local function location_handler(_, result, ctx, _)
  if result == nil or vim.tbl_isempty(result) then
    local _ = log.info() and log.info(ctx.method, 'No location found')
    return nil
  end
  local client = vim.lsp.get_client_by_id(ctx.client_id)

  -- textDocument/definition can return Location or Location[]
  -- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_definition

  if vim.tbl_islist(result) then
    jump_to_location(result[1], client.offset_encoding)

    if #result > 1 then
      vim.fn.setqflist({}, ' ', {
        title = 'LSP locations',
        items = util.locations_to_items(result, client.offset_encoding)
      })
      vim.api.nvim_command("botright copen")
    end
  else
    jump_to_location(result, client.offset_encoding)
  end
end

return {location_handler = location_handler}