[lua] Add events handling with Sprite.events & App.events

Added a new Events object with :on() and :off() methods to start or
stop listening to a specific event respectively. This also allows to
add several callbacks for the same event.

Replaced the temporal Site.onChange & Sprite.onChange implementations.

Related to several issues (enable more possibilities for): #138, #1403, #1949, #2965, #2980

laf

@@ -1 +1 @@
-Subproject commit f58ece8248e2ebf6124b28ec49044be913f57292
+Subproject commit c9bb18ba92915f0d9735da25360e4725f767b447

src/app/CMakeLists.txt

@@ -163,6 +163,7 @@ if(ENABLE_SCRIPTING)
     script/color_space_class.cpp
     script/dialog_class.cpp
     script/engine.cpp
+    script/events_class.cpp
     script/frame_class.cpp
     script/frames_class.cpp
     script/image_class.cpp

src/app/active_site_handler.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2021  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -28,10 +28,11 @@ ActiveSiteHandler::~ActiveSiteHandler()
 void ActiveSiteHandler::addDoc(Doc* doc)
 {
   Data data;
-  if (doc::Layer* layer = doc->sprite()->root()->firstLayer())
-    data.layer = layer->id();
-  else
-    data.layer = doc::NullId;
+  data.layer = doc::NullId;
+  if (doc->sprite()) {      // The sprite can be nullptr in some tests
+    if (doc::Layer* layer = doc->sprite()->root()->firstLayer())
+      data.layer = layer->id();
+  }
   data.frame = 0;
   m_data.insert(std::make_pair(doc, data));
   doc->add_observer(this);

src/app/context.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2020  Igara Studio S.A.
+// Copyright (C) 2018-2021  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -81,7 +81,7 @@ Doc* Context::activeDocument() const
 
 void Context::setActiveDocument(Doc* document)
 {
-  onSetActiveDocument(document);
+  onSetActiveDocument(document, true);
 }
 
 void Context::setActiveLayer(doc::Layer* layer)
@@ -206,15 +206,19 @@ void Context::onAddDocument(Doc* doc)
 
   if (m_activeSiteHandler)
     m_activeSiteHandler->addDoc(doc);
+
+  notifyActiveSiteChanged();
 }
 
 void Context::onRemoveDocument(Doc* doc)
 {
-  if (doc == m_lastSelectedDoc)
-    m_lastSelectedDoc = nullptr;
-
   if (m_activeSiteHandler)
     m_activeSiteHandler->removeDoc(doc);
+
+  if (doc == m_lastSelectedDoc) {
+    m_lastSelectedDoc = nullptr;
+    notifyActiveSiteChanged();
+  }
 }
 
 void Context::onGetActiveSite(Site* site) const
@@ -224,24 +228,33 @@ void Context::onGetActiveSite(Site* site) const
     activeSiteHandler()->getActiveSiteForDoc(doc, site);
 }
 
-void Context::onSetActiveDocument(Doc* doc)
+void Context::onSetActiveDocument(Doc* doc, bool notify)
 {
   m_lastSelectedDoc = doc;
+  if (notify)
+    notifyActiveSiteChanged();
 }
 
 void Context::onSetActiveLayer(doc::Layer* layer)
 {
   Doc* newDoc = (layer ? static_cast<Doc*>(layer->sprite()->document()): nullptr);
+  if (!newDoc)
+    return;
+
+  activeSiteHandler()->setActiveLayerInDoc(newDoc, layer);
+
   if (newDoc != m_lastSelectedDoc)
     setActiveDocument(newDoc);
-  if (newDoc)
-    activeSiteHandler()->setActiveLayerInDoc(newDoc, layer);
+  else
+    notifyActiveSiteChanged();
 }
 
 void Context::onSetActiveFrame(const doc::frame_t frame)
 {
   if (m_lastSelectedDoc)
     activeSiteHandler()->setActiveFrameInDoc(m_lastSelectedDoc, frame);
+
+  notifyActiveSiteChanged();
 }
 
 void Context::onSetRange(const DocRange& range)

src/app/context.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2020  Igara Studio S.A.
+// Copyright (C) 2018-2021  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -110,7 +110,7 @@ namespace app {
     void onRemoveDocument(Doc* doc) override;
 
     virtual void onGetActiveSite(Site* site) const;
-    virtual void onSetActiveDocument(Doc* doc);
+    virtual void onSetActiveDocument(Doc* doc, bool notify);
     virtual void onSetActiveLayer(doc::Layer* layer);
     virtual void onSetActiveFrame(const doc::frame_t frame);
     virtual void onSetRange(const DocRange& range);
@@ -122,10 +122,12 @@ namespace app {
   private:
     ActiveSiteHandler* activeSiteHandler() const;
 
+    // This must be defined before m_docs because ActiveSiteHandler
+    // will be an observer of all documents.
+    mutable std::unique_ptr<ActiveSiteHandler> m_activeSiteHandler;
     mutable Docs m_docs;
     ContextFlags m_flags;       // Last updated flags.
     Doc* m_lastSelectedDoc;
-    mutable std::unique_ptr<ActiveSiteHandler> m_activeSiteHandler;
     mutable std::unique_ptr<Preferences> m_preferences;
 
     DISABLE_COPYING(Context);

src/app/doc.cpp

@@ -70,6 +70,14 @@ Doc::Doc(Sprite* sprite)
 Doc::~Doc()
 {
   DOC_TRACE("DOC: Deleting", this);
+
+  try {
+    notify_observers<Doc*>(&DocObserver::onDestroy, this);
+  }
+  catch (...) {
+    LOG(ERROR, "DOC: Exception on DocObserver::onDestroy()\n");
+  }
+
   removeFromContext();
 }
 

src/app/doc_observer.h

@@ -17,6 +17,7 @@ namespace app {
   public:
     virtual ~DocObserver() { }
 
+    virtual void onDestroy(Doc* doc) { }
     virtual void onFileNameChanged(Doc* doc) { }
 
     // General update. If an observer receives this event, it's because
@@ -80,8 +81,6 @@ namespace app {
     // Slices
     virtual void onSliceNameChange(DocEvent& ev) { }
 
-    // Called to destroy the observable. (Here you could call "delete this".)
-    virtual void dispose() { }
   };
 
 } // namespace app

src/app/doc_undo_observer.h

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2021  Igara Studio S.A.
 // Copyright (C) 2015-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -19,12 +20,12 @@ namespace app {
   class DocUndoObserver {
   public:
     virtual ~DocUndoObserver() { }
-    virtual void onAddUndoState(DocUndo* history) = 0;
+    virtual void onAddUndoState(DocUndo* history) { }
     virtual void onDeleteUndoState(DocUndo* history,
-                                   undo::UndoState* state) = 0;
-    virtual void onCurrentUndoStateChange(DocUndo* history) = 0;
-    virtual void onClearRedo(DocUndo* history) = 0;
-    virtual void onTotalUndoSizeChange(DocUndo* history) = 0;
+                                   undo::UndoState* state) { }
+    virtual void onCurrentUndoStateChange(DocUndo* history) { }
+    virtual void onClearRedo(DocUndo* history) { }
+    virtual void onTotalUndoSizeChange(DocUndo* history) { }
   };
 
 } // namespace app

src/app/script/app_object.cpp

@@ -456,6 +456,12 @@ int App_useTool(lua_State* L)
   return 0;
 }
 
+int App_get_events(lua_State* L)
+{
+  push_app_events(L);
+  return 1;
+}
+
 int App_get_activeSprite(lua_State* L)
 {
   app::Context* ctx = App::instance()->context();
@@ -736,6 +742,7 @@ const Property App_properties[] = {
   { "range", App_get_range, nullptr },
   { "isUIAvailable", App_get_isUIAvailable, nullptr },
   { "defaultPalette", App_get_defaultPalette, App_set_defaultPalette },
+  { "events", App_get_events, nullptr },
   { nullptr, nullptr, nullptr }
 };
 

src/app/script/engine.cpp

@@ -155,6 +155,7 @@ void register_color_space_class(lua_State* L);
 #ifdef ENABLE_UI
 void register_dialog_class(lua_State* L);
 #endif
+void register_events_class(lua_State* L);
 void register_frame_class(lua_State* L);
 void register_frames_class(lua_State* L);
 void register_image_class(lua_State* L);
@@ -387,6 +388,7 @@ Engine::Engine()
 #ifdef ENABLE_UI
   register_dialog_class(L);
 #endif
+  register_events_class(L);
   register_frame_class(L);
   register_frames_class(L);
   register_image_class(L);

src/app/script/engine.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2020  Igara Studio S.A.
+// Copyright (C) 2018-2021  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -121,6 +121,7 @@ namespace app {
     EngineDelegate* m_oldDelegate;
   };
 
+  void push_app_events(lua_State* L);
   int push_image_iterator_function(lua_State* L, const doc::Image* image, int extraArgIndex);
   void push_brush(lua_State* L, const doc::BrushRef& brush);
   void push_cel_image(lua_State* L, doc::Cel* cel);
@@ -136,6 +137,7 @@ namespace app {
   void push_palette(lua_State* L, doc::Palette* palette);
   void push_plugin(lua_State* L, Extension* ext);
   void push_sprite_cel(lua_State* L, doc::Cel* cel);
+  void push_sprite_events(lua_State* L, doc::Sprite* sprite);
   void push_sprite_frame(lua_State* L, doc::Sprite* sprite, doc::frame_t frame);
   void push_sprite_frames(lua_State* L, doc::Sprite* sprite);
   void push_sprite_frames(lua_State* L, doc::Sprite* sprite, const std::vector<doc::frame_t>& frames);

src/app/script/events_class.cpp

@@ -0,0 +1,343 @@
+// Aseprite
+// Copyright (C) 2021  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/app.h"
+#include "app/context.h"
+#include "app/context_observer.h"
+#include "app/doc.h"
+#include "app/doc_undo.h"
+#include "app/doc_undo_observer.h"
+#include "app/script/docobj.h"
+#include "app/script/engine.h"
+#include "app/script/luacpp.h"
+#include "doc/document.h"
+#include "doc/sprite.h"
+
+#include <cstring>
+#include <map>
+#include <memory>
+
+namespace app {
+namespace script {
+
+using namespace doc;
+
+namespace {
+
+using EventListener = int;
+
+class AppEvents;
+class SpriteEvents;
+static std::unique_ptr<AppEvents> g_appEvents;
+static std::map<doc::ObjectId, std::unique_ptr<SpriteEvents>> g_spriteEvents;
+
+class Events {
+public:
+  using EventType = int;
+
+  Events() { }
+  virtual ~Events() { }
+  Events(const Events&) = delete;
+  Events& operator=(const Events&) = delete;
+
+  virtual EventType eventType(const char* eventName) const = 0;
+
+  bool hasListener(EventListener callbackRef) const {
+    for (auto& listeners : m_listeners) {
+      for (EventListener listener : listeners) {
+        if (listener == callbackRef)
+          return true;
+      }
+    }
+    return false;
+  }
+
+  void add(EventType eventType, EventListener callbackRef) {
+    if (eventType >= m_listeners.size())
+      m_listeners.resize(eventType+1);
+
+    auto& listeners = m_listeners[eventType];
+    listeners.push_back(callbackRef);
+    if (listeners.size() == 1)
+      onAddFirstListener(eventType);
+  }
+
+  void remove(EventListener callbackRef) {
+    for (int i=0; i<int(m_listeners.size()); ++i) {
+      EventListeners& listeners = m_listeners[i];
+      auto it = listeners.begin();
+      auto end = listeners.end();
+      bool removed = false;
+      for (; it != end; ) {
+        if (*it == callbackRef) {
+          removed = true;
+          it = listeners.erase(it);
+          end = listeners.end();
+        }
+        else
+          ++it;
+      }
+      if (removed && listeners.empty())
+        onRemoveLastListener(i);
+    }
+  }
+
+protected:
+  void call(EventType eventType) {
+    if (eventType >= m_listeners.size())
+      return;
+
+    script::Engine* engine = App::instance()->scriptEngine();
+    lua_State* L = engine->luaState();
+
+    try {
+      for (EventListener callbackRef : m_listeners[eventType]) {
+        lua_rawgeti(L, LUA_REGISTRYINDEX, callbackRef);
+        if (lua_pcall(L, 0, 0, 0)) {
+          if (const char* s = lua_tostring(L, -1))
+            engine->consolePrint(s);
+        }
+      }
+    }
+    catch (const std::exception& ex) {
+      engine->consolePrint(ex.what());
+    }
+  }
+
+private:
+  virtual void onAddFirstListener(EventType eventType) = 0;
+  virtual void onRemoveLastListener(EventType eventType) = 0;
+
+  using EventListeners = std::vector<EventListener>;
+  std::vector<EventListeners> m_listeners;
+};
+
+class AppEvents : public Events
+                , private ContextObserver {
+public:
+  enum : EventType { Unknown = -1, SiteChange };
+
+  AppEvents() {
+  }
+
+  EventType eventType(const char* eventName) const {
+    if (std::strcmp(eventName, "sitechange") == 0)
+      return SiteChange;
+    else
+      return Unknown;
+  }
+
+private:
+
+  void onAddFirstListener(EventType eventType) override {
+    switch (eventType) {
+      case SiteChange: {
+        App::instance()->context()->add_observer(this);
+        break;
+      }
+    }
+  }
+
+  void onRemoveLastListener(EventType eventType) override {
+    switch (eventType) {
+      case SiteChange: {
+        App::instance()->context()->remove_observer(this);
+        break;
+      }
+    }
+  }
+
+  // ContextObserver impl
+  void onActiveSiteChange(const Site& site) override { call(SiteChange); }
+};
+
+class SpriteEvents : public Events
+                   , public DocUndoObserver
+                   , public DocObserver {
+public:
+  enum : EventType { Unknown = -1, Change };
+
+  SpriteEvents(const Sprite* sprite)
+    : m_spriteId(sprite->id()) {
+    doc()->add_observer(this);
+  }
+
+  ~SpriteEvents() {
+    if (m_observingUndo) {
+      doc()->undoHistory()->remove_observer(this);
+      m_observingUndo = false;
+    }
+    doc()->remove_observer(this);
+  }
+
+  EventType eventType(const char* eventName) const {
+    if (std::strcmp(eventName, "change") == 0)
+      return Change;
+    else
+      return Unknown;
+  }
+
+  // DocObserver impl
+  void onDestroy(Doc* doc) override {
+    auto it = g_spriteEvents.find(m_spriteId);
+    ASSERT(it != g_spriteEvents.end());
+    if (it != g_spriteEvents.end())
+      g_spriteEvents.erase(it);
+  }
+
+  // DocUndoObserver impl
+  void onAddUndoState(DocUndo* history) override { call(Change);  }
+  void onCurrentUndoStateChange(DocUndo* history) override { call(Change); }
+
+private:
+
+  void onAddFirstListener(EventType eventType) override {
+    switch (eventType) {
+      case Change:
+        ASSERT(!m_observingUndo);
+        doc()->undoHistory()->add_observer(this);
+        m_observingUndo = true;
+        break;
+    }
+  }
+
+  void onRemoveLastListener(EventType eventType) override {
+    switch (eventType) {
+      case Change: {
+        if (m_observingUndo) {
+          doc()->undoHistory()->remove_observer(this);
+          m_observingUndo = false;
+        }
+        break;
+      }
+    }
+  }
+
+  Doc* doc() {
+    Sprite* sprite = doc::get<Sprite>(m_spriteId);
+    if (sprite)
+      return static_cast<Doc*>(sprite->document());
+    else
+      return nullptr;
+  }
+
+  ObjectId m_spriteId;
+  bool m_observingUndo = false;
+};
+
+int Events_on(lua_State* L)
+{
+  auto evs = get_ptr<Events>(L, 1);
+  const char* eventName = lua_tostring(L, 2);
+  if (!eventName)
+    return 0;
+
+  const int type = evs->eventType(eventName);
+  if (type < 0)
+    return luaL_error(L, "invalid event name to listen");
+
+  if (!lua_isfunction(L, 3))
+    return luaL_error(L, "second argument must be a function");
+
+  // Copy the callback function to add it to the global registry
+  lua_pushvalue(L, 3);
+  int callbackRef = luaL_ref(L, LUA_REGISTRYINDEX);
+  evs->add(type, callbackRef);
+
+  // Return the callback ref (this is an EventListener easier to use
+  // in Events_off())
+  lua_pushinteger(L, callbackRef);
+  return 1;
+}
+
+int Events_off(lua_State* L)
+{
+  auto evs = get_ptr<Events>(L, 1);
+  int callbackRef = LUA_REFNIL;
+
+  // Remove by listener value
+  if (lua_isinteger(L, 2)) {
+    callbackRef = lua_tointeger(L, 2);
+  }
+  // Remove by function reference
+  else if (lua_isfunction(L, 2)) {
+    lua_pushnil(L);
+    while (lua_next(L, LUA_REGISTRYINDEX) != 0) {
+      if (lua_isnumber(L, -2) &&
+          lua_isfunction(L, -1)) {
+        int i = lua_tointeger(L, -2);
+        if (// Compare value=function in 2nd argument
+            lua_compare(L, -1, 2, LUA_OPEQ) &&
+            // Check that this Events contain this reference
+            evs->hasListener(i)) {
+          callbackRef = i;
+          lua_pop(L, 2);  // Pop value and key
+          break;
+        }
+      }
+      lua_pop(L, 1); // Pop the value, leave the key for next lua_next()
+    }
+  }
+  else {
+    return luaL_error(L, "first argument must be a function or a EventListener");
+  }
+
+  if (callbackRef != LUA_REFNIL) {
+    evs->remove(callbackRef);
+    luaL_unref(L, LUA_REGISTRYINDEX, callbackRef);
+  }
+  return 0;
+}
+
+// We don't need a __gc (to call ~Events()), because Events instances
+// will be deleted when the Sprite is deleted or on App Exit
+const luaL_Reg Events_methods[] = {
+  { "on", Events_on },
+  { "off", Events_off },
+  { nullptr, nullptr }
+};
+
+} // anonymous namespace
+
+DEF_MTNAME(Events);
+
+void register_events_class(lua_State* L)
+{
+  REG_CLASS(L, Events);
+}
+
+void push_app_events(lua_State* L)
+{
+  if (!g_appEvents) {
+    App::instance()->Exit.connect([]{ g_appEvents.reset(); });
+    g_appEvents.reset(new AppEvents);
+  }
+  push_ptr<Events>(L, g_appEvents.get());
+}
+
+void push_sprite_events(lua_State* L, Sprite* sprite)
+{
+  ASSERT(sprite);
+
+  SpriteEvents* spriteEvents;
+
+  auto it = g_spriteEvents.find(sprite->id());
+  if (it != g_spriteEvents.end())
+    spriteEvents = it->second.get();
+  else {
+    spriteEvents = new SpriteEvents(sprite);
+    g_spriteEvents[sprite->id()].reset(spriteEvents);
+  }
+
+  push_ptr<Events>(L, spriteEvents);
+}
+
+} // namespace script
+} // namespace app

src/app/script/site_class.cpp

@@ -26,47 +26,6 @@ namespace script {
 
 namespace {
 
-class ScriptSiteObserver : public ContextObserver {
-public:
-  static ScriptSiteObserver* instance() {
-    static ScriptSiteObserver instance;
-    return &instance;
-  }
-
-  void onActiveSiteChange(const Site& site) {
-    if (m_onchangeRef == 0)
-      return;
-
-    script::Engine* engine = App::instance()->scriptEngine();
-    lua_State* L = engine->luaState();
-
-    lua_rawgeti(L, LUA_REGISTRYINDEX, m_onchangeRef);
-    if (lua_pcall(L, 0, 0, 0)) {
-      if (const char* s = lua_tostring(L, -1)) {
-        Console().printf("Error: %s", s);
-      }
-    }
-  }
-
-  int callbackRef() {
-    return m_onchangeRef;
-  }
-
-  void setCallbackRef(int onchangeRef) {
-    m_onchangeRef = onchangeRef;
-  }
-
-private:
-  ScriptSiteObserver()
-    : ContextObserver(),
-      m_onchangeRef(0)
-  { }
-
-  ~ScriptSiteObserver() { }
-
-  int m_onchangeRef;
-};
-
 int Site_get_sprite(lua_State* L)
 {
   auto site = get_obj<Site>(L, 1);
@@ -124,33 +83,6 @@ int Site_get_image(lua_State* L)
   return 1;
 }
 
-int Site_get_onChange(lua_State* L)
-{
-  lua_rawgeti(L, LUA_REGISTRYINDEX, ScriptSiteObserver::instance()->callbackRef());
-  return 1;
-}
-
-int Site_set_onChange(lua_State* L)
-{
-  auto site = get_obj<Site>(L, 1);
-  auto obs = ScriptSiteObserver::instance();
-
-  if (lua_isfunction(L, 2)) {
-    int onchangeRef = luaL_ref(L, LUA_REGISTRYINDEX);
-    if (!obs->callbackRef()) {
-      App::instance()->context()->add_observer(obs);
-    }
-    obs->setCallbackRef(onchangeRef);
-  }
-  else if (obs->callbackRef()) {
-    luaL_unref(L, LUA_REGISTRYINDEX, obs->callbackRef());
-    obs->setCallbackRef(0);
-    App::instance()->context()->remove_observer(obs);
-  }
-
-  return 0;
-}
-
 const luaL_Reg Site_methods[] = {
   { nullptr, nullptr }
 };
@@ -162,7 +94,6 @@ const Property Site_properties[] = {
   { "frame", Site_get_frame, nullptr },
   { "frameNumber", Site_get_frameNumber, nullptr },
   { "image", Site_get_image, nullptr },
-  { "onChange", Site_get_onChange, Site_set_onChange },
   { nullptr, nullptr, nullptr }
 };
 

src/app/script/sprite_class.cpp

@@ -59,41 +59,6 @@ namespace app {
 namespace script {
 
 namespace {
-// in lua, observers become `Sprite.onChange`
-class ScriptDocObserver : public DocUndoObserver {
-public:
-  ScriptDocObserver(int callbackRef)
-    : DocUndoObserver(),
-      m_callbackRef(callbackRef)
-  { }
-
-  void onAddUndoState(DocUndo* history) { callback();  }
-  void onDeleteUndoState(DocUndo* history, undo::UndoState* state) { }
-  void onCurrentUndoStateChange(DocUndo* history) { callback(); }
-  void onClearRedo(DocUndo* history) { }
-  void onTotalUndoSizeChange(DocUndo* history) { }
-
-  int callbackRef() { return m_callbackRef; }
-  void setCallbackRef(int callbackRef) { m_callbackRef = callbackRef; }
-
-private:
-  void callback() {
-    script::Engine* engine = App::instance()->scriptEngine();
-    lua_State* L = engine->luaState();
-
-    lua_rawgeti(L, LUA_REGISTRYINDEX, m_callbackRef);
-    if (lua_pcall(L, 0, 0, 0)) {
-      if (const char* s = lua_tostring(L, -1)) {
-        Console().printf("Error: %s", s);
-      }
-    }
-  }
-
-  int m_callbackRef;
-};
-
-// used to maintain one-to-one relation between sprites and observers
-std::map<doc::ObjectId, ScriptDocObserver*> script_observers;
 
 int Sprite_new(lua_State* L)
 {
@@ -627,47 +592,13 @@ int Sprite_deleteSlice(lua_State* L)
   }
 }
 
-int Sprite_get_onChange(lua_State* L)
+int Sprite_get_events(lua_State* L)
 {
   auto sprite = get_docobj<Sprite>(L, 1);
-  ScriptDocObserver* obs = script_observers[sprite->id()];
-
-  if (obs) {
-    lua_rawgeti(L, LUA_REGISTRYINDEX, obs->callbackRef());
-  }
-  else {
-    lua_pushnil(L);
-  }
+  push_sprite_events(L, sprite);
   return 1;
 }
 
-int Sprite_set_onChange(lua_State* L)
-{
-  auto sprite = get_docobj<Sprite>(L, 1);
-  auto doc = static_cast<Doc*>(sprite->document());
-  ScriptDocObserver* obs = script_observers[sprite->id()];
-
-  if (lua_isfunction(L, 2)) {
-    int callbackRef = luaL_ref(L, LUA_REGISTRYINDEX);
-    if (obs) {
-      obs->setCallbackRef(callbackRef);
-    }
-    else {
-      obs = new ScriptDocObserver(callbackRef);
-      doc->undoHistory()->add_observer(obs);
-      script_observers[sprite->id()] = obs;
-    }
-  }
-  else if (obs) {
-    doc->undoHistory()->remove_observer(obs);
-    script_observers.erase(sprite->id());
-    luaL_unref(L, LUA_REGISTRYINDEX, obs->callbackRef());
-    delete obs;
-  }
-
-  return 0;
-}
-
 int Sprite_get_filename(lua_State* L)
 {
   auto sprite = get_docobj<Sprite>(L, 1);
@@ -922,7 +853,7 @@ const Property Sprite_properties[] = {
   { "bounds", Sprite_get_bounds, nullptr },
   { "gridBounds", Sprite_get_gridBounds, Sprite_set_gridBounds },
   { "pixelRatio", Sprite_get_pixelRatio, Sprite_set_pixelRatio },
-  { "onChange", Sprite_get_onChange, Sprite_set_onChange },
+  { "events", Sprite_get_events, nullptr },
   { nullptr, nullptr, nullptr }
 };
 

src/app/ui_context.cpp

@@ -134,10 +134,10 @@ void UIContext::setActiveView(DocView* docView)
   notifyActiveSiteChanged();
 }
 
-void UIContext::onSetActiveDocument(Doc* document)
+void UIContext::onSetActiveDocument(Doc* document, bool notify)
 {
-  bool notify = (lastSelectedDoc() != document);
-  app::Context::onSetActiveDocument(document);
+  notify = (notify && lastSelectedDoc() != document);
+  app::Context::onSetActiveDocument(document, false);
 
   DocView* docView = getFirstDocView(document);
   if (docView) {     // The view can be null if we are in --batch mode

src/app/ui_context.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2021  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -53,7 +53,7 @@ namespace app {
     void onAddDocument(Doc* doc) override;
     void onRemoveDocument(Doc* doc) override;
     void onGetActiveSite(Site* site) const override;
-    void onSetActiveDocument(Doc* doc) override;
+    void onSetActiveDocument(Doc* doc, bool notify) override;
     void onSetActiveLayer(doc::Layer* layer) override;
     void onSetActiveFrame(const doc::frame_t frame) override;
     void onSetRange(const DocRange& range) override;