Fix possibilities of random crashes using filters w/Undo History window visible

Same problem as in 86a6462d7b82608cc14a8417bbdb42e2a4e3c467

src/app/commands/filters/filter_manager_impl.cpp

@@ -183,7 +183,7 @@ bool FilterManagerImpl::applyStep()
   return true;
 }
 
-void FilterManagerImpl::apply(Transaction& transaction)
+void FilterManagerImpl::apply()
 {
   bool cancelled = false;
 
@@ -203,7 +203,7 @@ void FilterManagerImpl::apply(Transaction& transaction)
     if (algorithm::shrink_bounds2(m_src.get(), m_dst.get(),
                                   m_bounds, output)) {
       if (m_cel->layer()->isBackground()) {
-        transaction.execute(
+        m_transaction->execute(
           new cmd::CopyRegion(
             m_cel->image(),
             m_dst.get(),
@@ -212,7 +212,7 @@ void FilterManagerImpl::apply(Transaction& transaction)
       }
       else {
         // Patch "m_cel"
-        transaction.execute(
+        m_transaction->execute(
           new cmd::PatchCel(
             m_cel, m_dst.get(),
             gfx::Region(output),
@@ -239,7 +239,7 @@ void FilterManagerImpl::applyToTarget()
   // Initialize writting operation
   ContextReader reader(m_context);
   ContextWriter writer(reader);
-  Transaction transaction(writer.context(), m_filter->getName(), ModifyDocument);
+  m_transaction.reset(new Transaction(writer.context(), m_filter->getName(), ModifyDocument));
 
   m_progressBase = 0.0f;
   m_progressWidth = 1.0f / images.size();
@@ -250,7 +250,7 @@ void FilterManagerImpl::applyToTarget()
   if (paletteChange) {
     Palette newPalette = *getNewPalette();
     restoreSpritePalette();
-    transaction.execute(
+    m_transaction->execute(
       new cmd::SetPalette(m_site.sprite(),
                           m_site.frame(), &newPalette));
   }
@@ -264,7 +264,7 @@ void FilterManagerImpl::applyToTarget()
     // Avoid applying the filter two times to the same image
     if (visited.find(image->id()) == visited.end()) {
       visited.insert(image->id());
-      applyToCel(transaction, it->cel());
+      applyToCel(it->cel());
     }
 
     // Is there a delegate to know if the process was cancelled by the user?
@@ -275,12 +275,17 @@ void FilterManagerImpl::applyToTarget()
     m_progressBase += m_progressWidth;
   }
 
-  transaction.commit();
-
   // Reset m_oldPalette to avoid restoring the color palette
   m_oldPalette.reset(nullptr);
 }
 
+void FilterManagerImpl::commitTransaction()
+{
+  // This must be executed in the main UI thread.
+  // Check Transaction::commit() comments.
+  m_transaction->commit();
+}
+
 void FilterManagerImpl::flush()
 {
   int h = m_row - m_nextRowToFlush;
@@ -395,10 +400,10 @@ void FilterManagerImpl::init(Cel* cel)
     m_target &= ~TARGET_ALPHA_CHANNEL;
 }
 
-void FilterManagerImpl::applyToCel(Transaction& transaction, Cel* cel)
+void FilterManagerImpl::applyToCel(Cel* cel)
 {
   init(cel);
-  apply(transaction);
+  apply();
 }
 
 bool FilterManagerImpl::updateBounds(doc::Mask* mask)

src/app/commands/filters/filter_manager_impl.h

@@ -19,6 +19,7 @@
 #include "gfx/rect.h"
 
 #include <cstring>
+#include <memory>
 
 namespace doc {
   class Cel;
@@ -82,6 +83,7 @@ namespace app {
     void end();
     bool applyStep();
     void applyToTarget();
+    void commitTransaction();
 
     app::Document* document();
     doc::Sprite* sprite() { return m_site.sprite(); }
@@ -114,8 +116,8 @@ namespace app {
 
   private:
     void init(doc::Cel* cel);
-    void apply(Transaction& transaction);
+    void apply();
-    void applyToCel(Transaction& transaction, doc::Cel* cel);
+    void applyToCel(doc::Cel* cel);
     bool updateBounds(doc::Mask* mask);
     bool paletteHasChanged();
     void restoreSpritePalette();
@@ -136,6 +138,7 @@ namespace app {
     Target m_targetOrig;          // Original targets
     Target m_target;              // Filtered targets
     base::UniquePtr<doc::Palette> m_oldPalette;
+    std::unique_ptr<Transaction> m_transaction;
 
     // Hooks
     float m_progressBase;

src/app/commands/filters/filter_worker.cpp

@@ -104,7 +104,9 @@ void FilterWorker::run()
 
   {
     scoped_lock lock(m_mutex);
-    if (!m_done)
+    if (m_done)
+      m_filterMgr->commitTransaction();
+    else
       m_cancelled = true;
   }
 

src/app/transaction.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2015  David Capello
+// Copyright (C) 2001-2017  David Capello
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -51,6 +51,11 @@ namespace app {
     // If you don't use this routine, all the changes will be discarded
     // (if the sprite's undo was enabled when the Transaction was
     // created).
+    //
+    // WARNING: This must be called from the main UI thread, because
+    // it will generate a DocumentUndo::add() which triggers a
+    // DocumentUndoObserver::onAddUndoState() notification, which
+    // updates the Undo History window UI.
     void commit();
 
     void execute(Cmd* cmd);