LSP: Move default buf callbacks to vim.lsp.callbacks (#11452)

- In the process, refactored focusable_preview to a util function.
- Add text for locations_to_items of the current line.
- Improve location callback to handle multiple return values by using
set_qflist.
- Remove update_tagstack and leave note for future travelers.

1 files changed, 223 insertions, 0 deletions

diff --git a/runtime/lua/vim/lsp/callbacks.lua b/runtime/lua/vim/lsp/callbacks.lua
new file mode 100644
index 0000000000..4fc3f74519
--- /dev/null
+++ b/runtime/lua/vim/lsp/callbacks.lua
@@ -0,0 +1,223 @@
+local log = require 'vim.lsp.log'
+local protocol = require 'vim.lsp.protocol'
+local util = require 'vim.lsp.util'
+local vim = vim
+local api = vim.api
+
+local M = {}
+
+local function err_message(...)
+  api.nvim_err_writeln(table.concat(vim.tbl_flatten{...}))
+  api.nvim_command("redraw")
+end
+
+M['workspace/applyEdit'] = function(_, _, workspace_edit)
+  if not workspace_edit then return end
+  -- TODO(ashkan) Do something more with label?
+  if workspace_edit.label then
+    print("Workspace edit", workspace_edit.label)
+  end
+  util.apply_workspace_edit(workspace_edit.edit)
+end
+
+M['textDocument/publishDiagnostics'] = function(_, _, result)
+  if not result then return end
+  local uri = result.uri
+  local bufnr = vim.uri_to_bufnr(uri)
+  if not bufnr then
+    err_message("LSP.publishDiagnostics: Couldn't find buffer for ", uri)
+    return
+  end
+  util.buf_clear_diagnostics(bufnr)
+  util.buf_diagnostics_save_positions(bufnr, result.diagnostics)
+  util.buf_diagnostics_underline(bufnr, result.diagnostics)
+  util.buf_diagnostics_virtual_text(bufnr, result.diagnostics)
+  -- util.set_loclist(result.diagnostics)
+end
+
+M['textDocument/references'] = function(_, _, result)
+  if not result then return end
+  util.set_qflist(result)
+  api.nvim_command("copen")
+  api.nvim_command("wincmd p")
+end
+
+M['textDocument/rename'] = function(_, _, result)
+  if not result then return end
+  util.apply_workspace_edit(result)
+end
+
+M['textDocument/rangeFormatting'] = function(_, _, result)
+  if not result then return end
+  util.apply_text_edits(result)
+end
+
+M['textDocument/formatting'] = function(_, _, result)
+  if not result then return end
+  util.apply_text_edits(result)
+end
+
+M['textDocument/completion'] = function(_, _, result)
+  if vim.tbl_isempty(result or {}) then return end
+  local row, col = unpack(api.nvim_win_get_cursor(0))
+  local line = assert(api.nvim_buf_get_lines(0, row-1, row, false)[1])
+  local line_to_cursor = line:sub(col+1)
+
+  local matches = util.text_document_completion_list_to_complete_items(result, line_to_cursor)
+  vim.fn.complete(col, matches)
+end
+
+M['textDocument/hover'] = function(_, method, result)
+  util.focusable_preview(method, function()
+    if not (result and result.contents) then
+      return { 'No information available' }
+    end
+    local markdown_lines = util.convert_input_to_markdown_lines(result.contents)
+    markdown_lines = util.trim_empty_lines(markdown_lines)
+    if vim.tbl_isempty(markdown_lines) then
+      return { 'No information available' }
+    end
+    return markdown_lines, util.try_trim_markdown_code_blocks(markdown_lines)
+  end)
+end
+
+local function location_callback(_, method, result)
+  if result == nil or vim.tbl_isempty(result) then
+    local _ = log.info() and log.info(method, 'No location found')
+    return nil
+  end
+  util.jump_to_location(result[1])
+  if #result > 1 then
+    util.set_qflist(result)
+    api.nvim_command("copen")
+    api.nvim_command("wincmd p")
+  end
+end
+
+M['textDocument/declaration'] = location_callback
+M['textDocument/definition'] = location_callback
+M['textDocument/typeDefinition'] = location_callback
+M['textDocument/implementation'] = location_callback
+
+--- Convert SignatureHelp response to preview contents.
+-- https://microsoft.github.io/language-server-protocol/specifications/specification-3-14/#textDocument_signatureHelp
+local function signature_help_to_preview_contents(input)
+  if not input.signatures then
+    return
+  end
+  --The active signature. If omitted or the value lies outside the range of
+  --`signatures` the value defaults to zero or is ignored if `signatures.length
+  --=== 0`. Whenever possible implementors should make an active decision about
+  --the active signature and shouldn't rely on a default value.
+  local contents = {}
+  local active_signature = input.activeSignature or 0
+  -- If the activeSignature is not inside the valid range, then clip it.
+  if active_signature >= #input.signatures then
+    active_signature = 0
+  end
+  local signature = input.signatures[active_signature + 1]
+  if not signature then
+    return
+  end
+  vim.list_extend(contents, vim.split(signature.label, '\n', true))
+  if signature.documentation then
+    util.convert_input_to_markdown_lines(signature.documentation, contents)
+  end
+  if input.parameters then
+    local active_parameter = input.activeParameter or 0
+    -- If the activeParameter is not inside the valid range, then clip it.
+    if active_parameter >= #input.parameters then
+      active_parameter = 0
+    end
+    local parameter = signature.parameters and signature.parameters[active_parameter]
+    if parameter then
+      --[=[
+      --Represents a parameter of a callable-signature. A parameter can
+      --have a label and a doc-comment.
+      interface ParameterInformation {
+        --The label of this parameter information.
+        --
+        --Either a string or an inclusive start and exclusive end offsets within its containing
+        --signature label. (see SignatureInformation.label). The offsets are based on a UTF-16
+        --string representation as `Position` and `Range` does.
+        --
+        --*Note*: a label of type string should be a substring of its containing signature label.
+        --Its intended use case is to highlight the parameter label part in the `SignatureInformation.label`.
+        label: string | [number, number];
+        --The human-readable doc-comment of this parameter. Will be shown
+        --in the UI but can be omitted.
+        documentation?: string | MarkupContent;
+      }
+      --]=]
+      -- TODO highlight parameter
+      if parameter.documentation then
+        util.convert_input_to_markdown_lines(parameter.documentation, contents)
+      end
+    end
+  end
+  return contents
+end
+
+M['textDocument/signatureHelp'] = function(_, method, result)
+  util.focusable_preview(method, function()
+    if not (result and result.signatures and result.signatures[1]) then
+      return { 'No signature available' }
+    end
+    -- TODO show popup when signatures is empty?
+    local lines = signature_help_to_preview_contents(result)
+    lines = util.trim_empty_lines(lines)
+    if vim.tbl_isempty(lines) then
+      return { 'No signature available' }
+    end
+    return lines, util.try_trim_markdown_code_blocks(lines)
+  end)
+end
+
+M['textDocument/peekDefinition'] = function(_, _, result, _)
+  if not (result and result[1]) then return end
+  local loc = result[1]
+  local bufnr = vim.uri_to_bufnr(loc.uri) or error("not found: "..tostring(loc.uri))
+  local start = loc.range.start
+  local finish = loc.range["end"]
+  util.open_floating_peek_preview(bufnr, start, finish, { offset_x = 1 })
+  local headbuf = util.open_floating_preview({"Peek:"}, nil, {
+    offset_y = -(finish.line - start.line);
+    width = finish.character - start.character + 2;
+  })
+  -- TODO(ashkan) change highlight group?
+  api.nvim_buf_add_highlight(headbuf, -1, 'Keyword', 0, -1)
+end
+
+local function log_message(_, _, result, client_id)
+  local message_type = result.type
+  local message = result.message
+  local client = vim.lsp.get_client_by_id(client_id)
+  local client_name = client and client.name or string.format("id=%d", client_id)
+  if not client then
+    err_message("LSP[", client_name, "] client has shut down after sending the message")
+  end
+  if message_type == protocol.MessageType.Error then
+    err_message("LSP[", client_name, "] ", message)
+  else
+    local message_type_name = protocol.MessageType[message_type]
+    api.nvim_out_write(string.format("LSP[%s][%s] %s\n", client_name, message_type_name, message))
+  end
+  return result
+end
+
+M['window/showMessage'] = log_message
+M['window/logMessage'] = log_message
+
+-- Add boilerplate error validation and logging for all of these.
+for k, fn in pairs(M) do
+  M[k] = function(err, method, params, client_id)
+    local _ = log.debug() and log.debug('default_callback', method, { params = params, client_id = client_id, err = err })
+    if err then
+      error(tostring(err))
+    end
+    return fn(err, method, params, client_id)
+  end
+end
+
+return M
+-- vim:sw=2 ts=2 et