POC for "rename" functionality

apps/language_server/lib/language_server/protocol.ex

@@ -181,6 +181,25 @@ defmodule ElixirLS.LanguageServer.Protocol do
     end
   end
 
+  defmacro rename_req(id, uri, line, character, new_name) do
+    quote do
+      request(unquote(id), "textDocument/rename", %{
+        "textDocument" => %{"uri" => unquote(uri)},
+        "position" => %{"line" => unquote(line), "character" => unquote(character)},
+        "newName" => unquote(new_name)
+      })
+    end
+  end
+
+  defmacro prepare_rename_req(id, uri, line, character) do
+    quote do
+      request(unquote(id), "textDocument/prepareRename", %{
+        "textDocument" => %{"uri" => unquote(uri)},
+        "position" => %{"line" => unquote(line), "character" => unquote(character)}
+      })
+    end
+  end
+
   defmacro execute_command_req(id, command, arguments) do
     quote do
       request(unquote(id), "workspace/executeCommand", %{

apps/language_server/lib/language_server/providers/rename.ex

@@ -0,0 +1,143 @@
+defmodule ElixirLS.LanguageServer.Providers.Rename do
+  @moduledoc """
+  Provides functionality to rename a symbol inside a workspace
+
+  https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_rename
+  """
+
+  alias ElixirLS.LanguageServer.SourceFile
+
+  def rename(%SourceFile{} = source_file, start_uri, line, character, new_name) do
+    edits =
+      with char_ident when not is_nil(char_ident) <-
+             get_char_ident(source_file.text, line, character),
+           %ElixirSense.Location{} = definition <-
+             ElixirSense.definition(source_file.text, line, character),
+           references <- ElixirSense.references(source_file.text, line, character) do
+        length_old = length(char_ident)
+
+        definition_references =
+          case definition do
+            %{file: nil, type: :function} ->
+              parse_definition_source_code(source_file.text)
+              |> get_all_fn_header_positions(char_ident)
+              |> positions_to_references(start_uri, length_old)
+
+            %{file: separate_file_path, type: :function} ->
+              parse_definition_source_code(definition)
+              |> get_all_fn_header_positions(char_ident)
+              |> positions_to_references(SourceFile.path_to_uri(separate_file_path), length_old)
+
+            _ ->
+              positions_to_references(
+                [{definition.line, definition.column}],
+                start_uri,
+                length_old
+              )
+          end
+
+        definition_references ++ repack_references(references, start_uri)
+      else
+        _ ->
+          []
+      end
+
+    changes =
+      edits
+      |> Enum.group_by(& &1.uri)
+      |> Enum.map(fn {uri, edits} ->
+        %{
+          "textDocument" => %{
+            "uri" => uri,
+            "version" => source_file.version + 1
+          },
+          "edits" =>
+            Enum.map(edits, fn edit ->
+              %{"range" => edit.range, "newText" => new_name}
+            end)
+        }
+      end)
+
+    {:ok, %{"documentChanges" => changes}}
+  end
+
+  def prepare(%SourceFile{} = source_file, _uri, line, character) do
+    result =
+      with %{
+             begin: {start_line, start_col},
+             end: {end_line, end_col},
+             context: {context, char_ident}
+           }
+           when context in [:local_or_var, :local_call] <-
+             Code.Fragment.surround_context(source_file.text, {line, character}) do
+        %{
+          range: adjust_range(start_line, start_col, end_line, end_col),
+          placeholder: to_string(char_ident)
+        }
+      else
+        _ ->
+          # Not a variable or local call, skipping for now
+          nil
+      end
+
+    {:ok, result}
+  end
+
+  defp repack_references(references, uri) do
+    for reference <- references do
+      %{
+        uri: uri,
+        range: %{
+          end: %{character: reference.range.end.column - 1, line: reference.range.end.line - 1},
+          start: %{
+            character: reference.range.start.column - 1,
+            line: reference.range.start.line - 1
+          }
+        }
+      }
+    end
+  end
+
+  defp parse_definition_source_code(%{file: file}) do
+    ElixirSense.Core.Parser.parse_file(file, true, true, 0)
+  end
+
+  defp parse_definition_source_code(source_text) when is_binary(source_text) do
+    ElixirSense.Core.Parser.parse_string(source_text, true, true, 0)
+  end
+
+  defp get_all_fn_header_positions(parsed_source, char_ident) do
+    parsed_source.mods_funs_to_positions
+    |> Map.filter(fn
+      {{_, fn_name, _}, _} -> Atom.to_charlist(fn_name) == char_ident
+    end)
+    |> Enum.flat_map(fn {_, %{positions: positions}} -> positions end)
+    |> Enum.uniq()
+  end
+
+  defp positions_to_references(header_positions, start_uri, length_old)
+       when is_list(header_positions) do
+    header_positions
+    |> Enum.map(fn {line, column} ->
+      %{
+        uri: start_uri,
+        range: adjust_range(line, column, line, column + length_old)
+      }
+    end)
+  end
+
+  defp adjust_range(start_line, start_character, end_line, end_character) do
+    %{
+      start: %{line: start_line - 1, character: start_character - 1},
+      end: %{line: end_line - 1, character: end_character - 1}
+    }
+  end
+
+  defp get_char_ident(text, line, character) do
+    case Code.Fragment.surround_context(text, {line, character}) do
+      %{context: {context, char_ident}} when context in [:local_or_var, :local_call] -> char_ident
+      %{context: {:dot, _, char_ident}} -> char_ident
+      _ -> nil
+    end
+  end
+end

apps/language_server/lib/language_server/server.ex

@@ -24,6 +24,7 @@ defmodule ElixirLS.LanguageServer.Server do
     Definition,
     Implementation,
     References,
+    Rename,
     Formatting,
     SignatureHelp,
     DocumentSymbols,
@@ -739,6 +740,26 @@ defmodule ElixirLS.LanguageServer.Server do
     {:async, fun, state}
   end
 
+  defp handle_request(rename_req(_id, uri, line, character, new_name), state = %__MODULE__{}) do
+    source_file = get_source_file(state, uri)
+
+    fun = fn ->
+      Rename.rename(source_file, uri, line + 1, character + 1, new_name)
+    end
+
+    {:async, fun, state}
+  end
+
+  defp handle_request(prepare_rename_req(_id, uri, line, character), state = %__MODULE__{}) do
+    source_file = get_source_file(state, uri)
+
+    fun = fn ->
+      Rename.prepare(source_file, uri, line + 1, character + 1)
+    end
+
+    {:async, fun, state}
+  end
+
   defp handle_request(execute_command_req(_id, command, args) = req, state = %__MODULE__{}) do
     {:async,
      fn ->
@@ -809,6 +830,7 @@ defmodule ElixirLS.LanguageServer.Server do
       "workspaceSymbolProvider" => true,
       "documentOnTypeFormattingProvider" => %{"firstTriggerCharacter" => "\n"},
       "codeLensProvider" => %{"resolveProvider" => false},
+      "renameProvider" => %{"prepareProvider" => true},
       "executeCommandProvider" => %{
         "commands" => ExecuteCommand.get_commands(server_instance_id)
       },