support navigating a file by its symbols in a seperate window

2 files changed, 148 insertions, 0 deletions

diff --git a/README.md b/README.md
index 806af12..de1206a 100644
--- a/README.md
+++ b/README.md
@@ -107,6 +107,7 @@ Alternatively, a plugin manager like [vis-plug](https://github.com/erf/vis-plug)
 	lspc-show-diagnostics - show the available diagnostics of the current line
 	lspc-next-diagnostic - jump to the next available diagnostic
 	lspc-prev-diagnostic - jump to the previous available diagnostic
+	lspc-navigate-symbols - navigate a file by its symbols in a seperate window
 
 ### Available configuration options
 
diff --git a/init.lua b/init.lua
index 9a40bf9..8953847 100644
--- a/init.lua
+++ b/init.lua
@@ -728,6 +728,14 @@ function LanguageServer:call_text_document_method(method, params, win, ctx)
   self:request_diagnostics(win)
 end
 
+--- Call the textDocument/symbol method of the server if provided
+function LanguageServer:request_symbols(win, ctx)
+  if self.capabilities['documentSymbolProvider'] then
+    local params = {textDocument = {uri = path_to_uri(win.file.path)}}
+    self:call_text_document_method('documentSymbol', params, win, ctx)
+  end
+end
+
 local function lspc_handle_goto_method_response(req, result)
   if not result or type(result) ~= 'table' or next(result) == nil then
     lspc:warn(req.method .. ' found no results')
@@ -962,6 +970,12 @@ local function lspc_handle_initialize_response(ls, result)
   vis.events.emit(lspc.events.LS_INITIALIZED, ls)
 end
 
+local function lspc_handle_symbol_method_response(result, ctx)
+  if ctx.callback and type(ctx.callback) == 'function' then
+    ctx.callback(result, ctx)
+  end
+end
+
 --- Send didChangeConfiguration notification with the default settings
 function LanguageServer:send_default_settings()
   -- Use the rootUri or the open file's path as scope for the initial settings
@@ -1023,6 +1037,9 @@ function LanguageServer:handle_method_response(method_response, req)
   elseif method == 'textDocument/diagnostic' then
     lspc_handle_diagnostic_method_response(self, result, req.ctx)
 
+  elseif method == 'textDocument/documentSymbol' then
+    lspc_handle_symbol_method_response(result, req.ctx)
+
   elseif method == 'shutdown' then
     self:send_notification('exit')
     self.fd:close()
@@ -1558,6 +1575,123 @@ local function lspc_show_diagnostic(win, line)
   end
 end
 
+local lsp_symbol_kinds = {
+  'File',
+  'Module',
+  'Namespace',
+  'Package',
+  'Class',
+  'Method',
+  'Property',
+  'Field',
+  'Constructor',
+  'Enum',
+  'Interface',
+  'Function',
+  'Variable',
+  'Constant',
+  'String',
+  'Number',
+  'Boolean',
+  'Array',
+  'Object',
+  'Key',
+  'Null',
+  'EnumMember',
+  'Struct',
+  'Event',
+  'Operator',
+  'TypeParameter',
+}
+
+local function recursive_bfs_symbols_flatten(symbols, indent)
+  local ranges = {}
+  local str = ''
+  for _, s in ipairs(symbols) do
+    local range = s.selectionRange or s.location.range
+    table.insert(ranges, range)
+    str = str ..
+              string.format('%s%s %s %d:%d\n', indent, lsp_symbol_kinds[s.kind], s.name,
+                            range.start.line + 1, range.start.character + 1)
+    -- Remember DocumentSymbol.selectionRange or SymbolInformation.location.range
+    if s.children then
+      local cstr, cranges = recursive_bfs_symbols_flatten(s.children, indent .. '  ')
+      str = str .. cstr
+      for _, v in ipairs(cranges) do
+        table.insert(ranges, v)
+      end
+    end
+  end
+  return str, ranges
+end
+
+local function lspc_navwin_from_symbols(symbols, ctx)
+  local symbols_outline, ranges = recursive_bfs_symbols_flatten(symbols, '')
+
+  local old_layout = vis.ui.layout
+  vis:command('vsplit')
+  local navwin = ctx.win
+  local codewin = vis.win
+
+  -- Prepare window to be our symbol navigation window
+  navwin.file = 'symbols'
+  local navfile = navwin.file
+  navfile:delete(0, navfile.size)
+  navfile:insert(0, symbols_outline)
+  navwin:draw()
+  -- Jump to navigation window
+  vis.win = navwin
+
+  -- Create event handlers to connect the position in the navigation window to
+  -- the original window.
+  local function nav_win_win_highlight_handler(win)
+    -- This is not the navigation window
+    if win ~= navwin then
+      return true
+    end
+
+    -- No valid selection in the navigation window
+    local line = navwin.selection.line
+    if line > #ranges then
+      return true
+    end
+    local sel = lsp_pos_to_vis_sel(ranges[navwin.selection.line].start)
+
+    -- Set the selection in the code window to the selected symbol
+    codewin.selection:to(sel.line, sel.col)
+    return true
+  end
+  vis.events.subscribe(vis.events.WIN_HIGHLIGHT, nav_win_win_highlight_handler)
+
+  -- Remove the event handlers.
+  local nav_win_close_handler
+  nav_win_close_handler = function(win)
+    if win ~= navwin and win ~= codewin then
+      return true
+      -- The code windows was closed, therefore we can also close the navigation window
+    elseif win == codewin then
+      navwin:close(true)
+      -- Reset everything after closing the navigation window
+    else
+      -- reset vis' layout
+      vis.ui.layout = old_layout
+      vis.ui.layout = vis.ui.layouts.HORIZONTAL
+
+      -- remove the navigation window event handlers
+      vis.events.unsubscribe(vis.events.UI_DRAW, nav_win_win_highlight_handler)
+      vis.events.unsubscribe(vis.events.WIN_CLOSE, nav_win_close_handler)
+    end
+    return true
+  end
+
+  vis.events.subscribe(vis.events.WIN_CLOSE, nav_win_close_handler)
+end
+
+local function lspc_nav_symbols(ls, win)
+  local ctx = {win = win, callback = lspc_navwin_from_symbols}
+  ls:request_symbols(win, ctx)
+end
+
 -- vis-lspc commands
 
 vis:command_register('lspc-back', function()
@@ -1784,6 +1918,19 @@ vis:command_register('lspc-show-diagnostics', function(argv, _, win)
   end
 end)
 
+vis:command_register('lspc-navigate-symbols', function(argv, _, win)
+  local ls, err = lspc_get_usable_ls(win, argv[1])
+  if err then
+    lspc:err(err)
+    return
+  end
+  assert(ls)
+  if not ls:is_file_opened(win.file.path) then
+    lspc_open(ls, win, win.file)
+  end
+  lspc_nav_symbols(ls, win)
+end, 'navigate the file by its symbols')
+
 -- vis-lspc event hooks
 vis.events.subscribe(vis.events.WIN_OPEN, function(win)
   if lspc.autostart and win.syntax then