feat(builtin.lsp): implement builtin handlers for lsp.(incoming|outgo…

…ing)_calls

Fixes #863

README.md

@@ -295,6 +295,8 @@ Built-in functions. Ready to be bound to any key you like.
 | Functions                                   | Description                                                                                                               |
 |---------------------------------------------|---------------------------------------------------------------------------------------------------------------------------|
 | `builtin.lsp_references`                    | Lists LSP references for word under the cursor                                                                            |
+| `builtin.lsp_incoming_calls`                | Lists LSP incoming calls for word under the cursor                                                                        |
+| `builtin.lsp_outgoing_calls`                | Lists LSP outgoing calls for word under the cursor                                                                        |
 | `builtin.lsp_document_symbols`              | Lists LSP document symbols in the current buffer                                                                          |
 | `builtin.lsp_workspace_symbols`             | Lists LSP document symbols in the current workspace                                                                       |
 | `builtin.lsp_dynamic_workspace_symbols`     | Dynamically Lists LSP for all workspace symbols                                                                           |

lua/telescope/builtin/init.lua

@@ -368,6 +368,16 @@ builtin.jumplist = require_on_exported_call("telescope.builtin.internal").jumpli
 ---@field timeout number: timeout for the sync call (default: 10000)
 builtin.lsp_references = require_on_exported_call("telescope.builtin.lsp").references
 
+--- Lists LSP incoming calls for word under the cursor, jumps to reference on `<cr>`
+---@param opts table: options to pass to the picker
+---@field timeout number: timeout for the sync call (default: 10000)
+builtin.lsp_incoming_calls = require_on_exported_call("telescope.builtin.lsp").incoming_calls
+
+--- Lists LSP outgoing calls for word under the cursor, jumps to reference on `<cr>`
+---@param opts table: options to pass to the picker
+---@field timeout number: timeout for the sync call (default: 10000)
+builtin.lsp_outgoing_calls = require_on_exported_call("telescope.builtin.lsp").outgoing_calls
+
 --- Goto the definition of the word under the cursor, if there's only one, otherwise show all options in Telescope
 ---@param opts table: options to pass to the picker
 ---@field timeout number: timeout for the sync call (default: 10000)

lua/telescope/builtin/lsp.lua

@@ -44,6 +44,106 @@ lsp.references = function(opts)
   }):find()
 end
 
+local function call_hierarchy(method, title, direction, opts, item, timeout)
+  local result, err = vim.lsp.buf_request_sync(0, method, { item = item }, timeout)
+  if err then
+    vim.api.nvim_err_writeln("Error handling " .. title .. ": " .. err)
+    return
+  end
+  if not result or vim.tbl_isempty(result) then
+    return
+  end
+  local locations = {}
+  for _, server_result in pairs(result) do
+    for _, ch_call in pairs(server_result.result) do
+      local ch_item = ch_call[direction]
+      for _, range in pairs(ch_call.fromRanges) do
+        table.insert(locations, {
+          filename = vim.uri_to_fname(ch_item.uri),
+          text = ch_item.name,
+          lnum = range.start.line + 1,
+          col = range.start.character + 1,
+        })
+      end
+    end
+  end
+  pickers.new(opts, {
+    prompt_title = title,
+    finder = finders.new_table {
+      results = locations,
+      entry_maker = opts.entry_maker or make_entry.gen_from_quickfix(opts),
+    },
+    previewer = conf.qflist_previewer(opts),
+    sorter = conf.generic_sorter(opts),
+  }):find()
+end
+
+local function calls(opts, direction)
+  opts = opts or {}
+
+  local params = vim.lsp.util.make_position_params()
+  local timeout = opts.timeout or 10000
+  local start = os.time()
+  local result, err = vim.lsp.buf_request_sync(0, "textDocument/prepareCallHierarchy", params, timeout)
+  if err then
+    vim.api.nvim_err_writeln("Error when preparing call hierarchy: " .. err)
+    return
+  end
+  -- NOTE: os.time() and os.difftime() only have second precision so we might stop too early later on
+  local remaining = timeout - os.difftime(os.time(), start)
+
+  local flattened_results = {}
+  for _, server_results in pairs(result) do
+    if server_results.result then
+      for _, result_result in pairs(server_results.result) do
+        if not vim.tbl_islist(result_result) then
+          flattened_results = { result_result }
+          break
+        end
+
+        vim.list_extend(flattened_results, server_results.result)
+      end
+    end
+  end
+  if #flattened_results == 0 then
+    return
+  else
+    if #flattened_results == 1 then
+      if direction == "from" then
+        call_hierarchy(
+          "callHierarchy/incomingCalls",
+          "LSP Incoming Calls",
+          direction,
+          opts,
+          flattened_results[1],
+          remaining
+        )
+      else
+        call_hierarchy(
+          "callHierarchy/outgoingCalls",
+          "LSP Outgoing Calls",
+          direction,
+          opts,
+          flattened_results[1],
+          remaining
+        )
+      end
+    else
+      -- TODO: handle more than one candidate
+      -- Based on LSP spec there could be several candidates and the client hasn
+      -- to choose among them.
+    end
+  end
+end
+
+lsp.incoming_calls = function(opts)
+  calls(opts, "from")
+end
+
+lsp.outgoing_calls = function(opts)
+  calls(opts, "to")
+end
+
 local function list_or_jump(action, title, opts)
   opts = opts or {}
 
@@ -486,6 +586,8 @@ local feature_map = {
   ["type_definitions"] = "type_definition",
   ["implementations"] = "implementation",
   ["workspace_symbols"] = "workspace_symbol",
+  ["incoming_calls"] = "call_hierarchy",
+  ["outgoing_calls"] = "call_hierarchy",
 }
 
 local function apply_checks(mod)