feat(events): Emitter passes event objects. Allow stopping propagation.

Author: sindrets

lua/diffview/bootstrap.lua

@@ -38,8 +38,8 @@ _G.DiffviewGlobal = {
 
 DiffviewGlobal.emitter:on_any(function(event, args)
   local utils = require("diffview.utils")
-  require("diffview").nore_emit(event, utils.tbl_unpack(args))
-  require("diffview.config").user_emitter:nore_emit(event, utils.tbl_unpack(args))
+  require("diffview").nore_emit(event.id, utils.tbl_unpack(args))
+  require("diffview.config").user_emitter:nore_emit(event.id, utils.tbl_unpack(args))
 end)
 
 return true

lua/diffview/config.lua

@@ -491,7 +491,9 @@ function M.setup(user_config)
 
   for event, callback in pairs(M._config.hooks) do
     if type(callback) == "function" then
-      M.user_emitter:on(event, callback)
+      M.user_emitter:on(event, function (_, ...)
+        callback(...)
+      end)
     end
   end
 

lua/diffview/events.lua

@@ -6,8 +6,8 @@ local utils = lazy.require("diffview.utils")
 
 local M = {}
 
----@enum Event
-local Event = {
+---@enum EventName
+local EventName = {
   FILES_STAGED = 1,
 }
 
@@ -18,10 +18,26 @@ local Event = {
 ---@field callback function The original callback
 ---@field call function
 
+---@class Event : diffview.Object
+---@operator call:Event
+---@field id any
+---@field propagate boolean
+local Event = oop.create_class("Event")
+
+function Event:init(opt)
+  self.id = opt.id
+  self.propagate = true
+end
+
+function Event:stop_propagation()
+  self.propagate = false
+end
+
+
 ---@class EventEmitter : diffview.Object
----@field event_map table<Event, Listener[]> # Registered events mapped to subscribed listeners.
+---@field event_map table<any, Listener[]> # Registered events mapped to subscribed listeners.
 ---@field any_listeners Listener[] # Listeners subscribed to all events.
----@field emit_lock table<Event, boolean>
+---@field emit_lock table<any, boolean>
 local EventEmitter = oop.create_class("EventEmitter")
 
 ---EventEmitter constructor.
@@ -32,49 +48,48 @@ function EventEmitter:init()
 end
 
 ---Subscribe to a given event.
----@param event any Event identifier.
----@param callback function
-function EventEmitter:on(event, callback)
-  if not self.event_map[event] then
-    self.event_map[event] = {}
+---@param event_id any Event identifier.
+---@param callback fun(event: Event, ...)
+function EventEmitter:on(event_id, callback)
+  if not self.event_map[event_id] then
+    self.event_map[event_id] = {}
   end
 
-  table.insert(self.event_map[event], {
+  table.insert(self.event_map[event_id], 1, {
     type = "normal",
     callback = callback,
-    call = function(args)
-      return callback(utils.tbl_unpack(args))
+    call = function(event, args)
+      return callback(event, utils.tbl_unpack(args))
     end,
   })
 end
 
 ---Subscribe a one-shot listener to a given event.
----@param event any Event identifier.
----@param callback function
-function EventEmitter:once(event, callback)
-  if not self.event_map[event] then
-    self.event_map[event] = {}
+---@param event_id any Event identifier.
+---@param callback fun(event: Event, ...)
+function EventEmitter:once(event_id, callback)
+  if not self.event_map[event_id] then
+    self.event_map[event_id] = {}
   end
 
   local emitted = false
 
-  table.insert(self.event_map[event], {
+  table.insert(self.event_map[event_id], 1, {
     type = "once",
     callback = callback,
-    call = function(args)
+    call = function(event, args)
       if not emitted then
         emitted = true
-        self:off(callback, event)
-        return callback(utils.tbl_unpack(args))
+        return callback(event, utils.tbl_unpack(args))
       end
     end,
   })
 end
 
 ---Add a new any-listener, subscribed to all events.
----@param callback function
+---@param callback fun(event: Event, ...)
 function EventEmitter:on_any(callback)
-  table.insert(self.any_listeners, {
+  table.insert(self.any_listeners, 1, {
     type = "any",
     callback = callback,
     call = function(event, args)
@@ -84,11 +99,11 @@ function EventEmitter:on_any(callback)
 end
 
 ---Add a new one-shot any-listener, subscribed to all events.
----@param callback function
+---@param callback fun(event: Event, ...)
 function EventEmitter:once_any(callback)
   local emitted = false
 
-  table.insert(self.any_listeners, {
+  table.insert(self.any_listeners, 1, {
     type = "any_once",
     callback = callback,
     call = function(event, args)
@@ -103,13 +118,13 @@ end
 ---Unsubscribe a listener. If no event is given, the listener is unsubscribed
 ---from all events.
 ---@param callback function
----@param event? any Only unsubscribe listeners from this event.
-function EventEmitter:off(callback, event)
+---@param event_id? any Only unsubscribe listeners from this event.
+function EventEmitter:off(callback, event_id)
   ---@type Listener[][]
   local all
 
-  if event then
-    all = { self.event_map[event] }
+  if event_id then
+    all = { self.event_map[event_id] }
   else
     all = utils.vec_join(
       vim.tbl_values(self.event_map),
@@ -133,63 +148,87 @@ function EventEmitter:off(callback, event)
 end
 
 ---Clear all listeners for a given event. If no event is given: clear all listeners.
----@param event any?
-function EventEmitter:clear(event)
+---@param event_id any?
+function EventEmitter:clear(event_id)
   for e, _ in pairs(self.event_map) do
-    if event == nil or event == e then
+    if event_id == nil or event_id == e then
       self.event_map[e] = nil
     end
   end
 end
 
+---@param listeners Listener[]
+---@param event Event
+---@param args table
+---@return Listener[]
+local function filter_call(listeners, event, args)
+  listeners = utils.vec_slice(listeners) --[[@as Listener[] ]]
+  local result = {}
+
+  for i = 1, #listeners do
+    local cur = listeners[i]
+    local ret = cur.call(event, args)
+
+    if not (cur.type == "once" or cur.type == "any_once") and not ret then
+      result[#result + 1] = cur
+    end
+
+    if not event.propagate then
+      for j = i + 1, #listeners do result[j] = listeners[j] end
+      break
+    end
+  end
+
+  return result
+end
+
 ---Notify all listeners subscribed to a given event.
----@param event any Event identifier.
+---@param event_id any Event identifier.
 ---@param ... any Event callback args.
-function EventEmitter:emit(event, ...)
-  if not self.emit_lock[event] then
+function EventEmitter:emit(event_id, ...)
+  if not self.emit_lock[event_id] then
     local args = utils.tbl_pack(...)
+    local e = Event({ id = event_id })
 
-    if type(self.event_map[event]) == "table" then
-      self.event_map[event] = utils.tbl_fmap(self.event_map[event], function(listeners)
-        return not listeners.call(args) and listeners or nil
-      end)
+    if type(self.event_map[event_id]) == "table" then
+      self.event_map[event_id] = filter_call(self.event_map[event_id], e, args)
     end
 
-    self.any_listeners = utils.tbl_fmap(self.any_listeners, function(listeners)
-      return not listeners.call(event, args) and listeners or nil
-    end)
+    if e.propagate then
+      self.any_listeners = filter_call(self.any_listeners, e, args)
+    end
   end
 end
 
 ---Non-recursively notify all listeners subscribed to a given event.
----@param event any Event identifier.
+---@param event_id any Event identifier.
 ---@param ... any Event callback args.
-function EventEmitter:nore_emit(event, ...)
-  if not self.emit_lock[event] then
-    self.emit_lock[event] = true
+function EventEmitter:nore_emit(event_id, ...)
+  if not self.emit_lock[event_id] then
+    self.emit_lock[event_id] = true
     local args = utils.tbl_pack(...)
+    local e = Event({ id = event_id })
 
-    if type(self.event_map[event]) == "table" then
-      self.event_map[event] = utils.tbl_fmap(self.event_map[event], function(listeners)
-        return not listeners.call(args) and listeners or nil
-      end)
+    if type(self.event_map[event_id]) == "table" then
+      self.event_map[event_id] = filter_call(self.event_map[event_id], e, args)
     end
 
-    self.any_listeners = utils.tbl_fmap(self.any_listeners, function(listeners)
-      return not listeners.call(event, args) and listeners or nil
-    end)
+    if e.propagate then
+      self.any_listeners = filter_call(self.any_listeners, e, args)
+    end
 
-    self.emit_lock[event] = false
+    self.emit_lock[event_id] = false
   end
 end
 
 ---Get all listeners subscribed to the given event.
----@param event any Event identifier.
+---@param event_id any Event identifier.
 ---@return Listener[]?
-function EventEmitter:get(event)
-  return self.event_map[event]
+function EventEmitter:get(event_id)
+  return self.event_map[event_id]
 end
 
+M.EventName = EventName
 M.Event = Event
 M.EventEmitter = EventEmitter
 return M

lua/diffview/scene/layout.lua

@@ -23,13 +23,13 @@ function Layout:init(opt)
 
     ---@param other Layout
     ---@diagnostic disable-next-line: unused-local
-    self.emitter:on("create_pre", function(other)
+    self.emitter:on("create_pre", function(_, other)
       last_equalalways = vim.o.equalalways
       vim.opt.equalalways = true
     end)
 
     ---@param other Layout
-    self.emitter:on("create_post", function(other)
+    self.emitter:on("create_post", function(_, other)
       other:open_null()
       other:open_files()
       vim.opt.equalalways = last_equalalways

lua/diffview/scene/view.lua

@@ -52,7 +52,7 @@ function View:init(opt)
   self.closing = utils.sate(opt.closing, false)
 
   local function wrap_event(event)
-    DiffviewGlobal.emitter:on(event, function(view, ...)
+    DiffviewGlobal.emitter:on(event, function(_, view, ...)
       local cur_view = require("diffview.lib").get_current_view()
 
       if (view and view == self) or (not view and cur_view == self) then

lua/diffview/scene/views/diff/diff_view.lua

@@ -4,7 +4,7 @@ local oop = require("diffview.oop")
 local CommitLogPanel = lazy.access("diffview.ui.panels.commit_log_panel", "CommitLogPanel") ---@type CommitLogPanel|LazyModule
 local Diff = lazy.access("diffview.diff", "Diff") ---@type Diff|LazyModule
 local EditToken = lazy.access("diffview.diff", "EditToken") ---@type EditToken|LazyModule
-local Event = lazy.access("diffview.events", "Event") ---@type Event|LazyModule
+local EventName = lazy.access("diffview.events", "EventName") ---@type EventName|LazyModule
 local FileDict = lazy.access("diffview.vcs.file_dict", "FileDict") ---@type FileDict|LazyModule
 local FileEntry = lazy.access("diffview.scene.file_entry", "FileEntry") ---@type FileEntry|LazyModule
 local FilePanel = lazy.access("diffview.scene.views.diff.file_panel", "FilePanel") ---@type FilePanel|LazyModule
@@ -71,7 +71,7 @@ function DiffView:init(opt)
   self.attached_bufs = {}
 
   ---@param entry FileEntry
-  self.emitter:on("file_open_post", function(entry)
+  self.emitter:on("file_open_post", function(_, entry)
     if entry.kind == "conflicting" then
       local file = entry.layout:get_main_win().file
 
@@ -466,7 +466,7 @@ function DiffView:file_safeguard()
 end
 
 function DiffView:on_files_staged(callback)
-  self.emitter:on(Event.FILES_STAGED, callback)
+  self.emitter:on(EventName.FILES_STAGED, callback)
 end
 
 function DiffView:init_event_listeners()

lua/diffview/scene/views/diff/listeners.lua

@@ -1,6 +1,6 @@
 local lazy = require("diffview.lazy")
 
-local Event = lazy.access("diffview.events", "Event") ---@type Event|LazyModule
+local EventName = lazy.access("diffview.events", "EventName") ---@type EventName|LazyModule
 local RevType = lazy.access("diffview.vcs.rev", "RevType") ---@type RevType|LazyModule
 local actions = lazy.require("diffview.actions") ---@module "diffview.actions"
 local async = lazy.require("plenary.async") ---@module "plenary.async"
@@ -52,7 +52,7 @@ return function(view)
       end
     end,
     ---@diagnostic disable-next-line: unused-local
-    files_updated = function(files)
+    files_updated = function(_, files)
       view.initialized = true
     end,
     close = function()
@@ -171,7 +171,7 @@ return function(view)
         view:update_files(function()
           view.panel:highlight_cur_file()
         end)
-        view.emitter:emit(Event.FILES_STAGED, view)
+        view.emitter:emit(EventName.FILES_STAGED, view)
       end
     end,
     stage_all = function()
@@ -190,7 +190,7 @@ return function(view)
         view:update_files(function()
           view.panel:highlight_cur_file()
         end)
-        view.emitter:emit(Event.FILES_STAGED, view)
+        view.emitter:emit(EventName.FILES_STAGED, view)
       end
     end,
     unstage_all = function()
@@ -202,7 +202,7 @@ return function(view)
       end
 
       view:update_files()
-      view.emitter:emit(Event.FILES_STAGED, view)
+      view.emitter:emit(EventName.FILES_STAGED, view)
     end,
     restore_entry = async.void(function()
       local commit

lua/diffview/scene/views/file_history/file_history_view.lua

@@ -2,7 +2,7 @@ local lazy = require("diffview.lazy")
 local oop = require("diffview.oop")
 
 local CommitLogPanel = lazy.access("diffview.ui.panels.commit_log_panel", "CommitLogPanel") ---@type CommitLogPanel|LazyModule
-local Event = lazy.access("diffview.events", "Event") ---@type Event|LazyModule
+local EventName = lazy.access("diffview.events", "EventName") ---@type EventName|LazyModule
 local FileEntry = lazy.access("diffview.scene.file_entry", "FileEntry") ---@type FileEntry|LazyModule
 local FileHistoryPanel = lazy.access("diffview.scene.views.file_history.file_history_panel", "FileHistoryPanel") ---@type FileHistoryPanel|LazyModule
 local JobStatus = lazy.access("diffview.vcs.utils", "JobStatus") ---@type JobStatus|LazyModule
@@ -173,7 +173,7 @@ function FileHistoryView:file_safeguard()
 end
 
 function FileHistoryView:on_files_staged(callback)
-  self.emitter:on(Event.FILES_STAGED, callback)
+  self.emitter:on(EventName.FILES_STAGED, callback)
 end
 
 function FileHistoryView:init_event_listeners()