FontEditor: Propagate errors when pushing undo commands

3 files changed, 40 insertions, 12 deletions

diff --git a/Userland/Applications/FontEditor/FontEditor.cpp b/Userland/Applications/FontEditor/FontEditor.cpp
index c5833aa7a2..383ec3905f 100644
--- a/Userland/Applications/FontEditor/FontEditor.cpp
+++ b/Userland/Applications/FontEditor/FontEditor.cpp
@@ -739,6 +739,24 @@ bool FontEditorWidget::open_file(String const& path)
     return true;
 }
 
+void FontEditorWidget::push_undo()
+{
+    auto maybe_state = m_undo_selection->save_state();
+    if (maybe_state.is_error()) {
+        warnln("Failed to save undo state: {}", maybe_state.error());
+        return;
+    }
+    auto state = maybe_state.release_value();
+    auto maybe_command = try_make<SelectionUndoCommand>(*m_undo_selection, move(state));
+    if (maybe_command.is_error()) {
+        warnln("Failed to make undo command: {}", maybe_command.error());
+        return;
+    }
+    auto command = maybe_command.release_value();
+    if (auto maybe_push = m_undo_stack->try_push(move(command)); maybe_push.is_error())
+        warnln("Failed to push undo stack: {}", maybe_push.error());
+}
+
 void FontEditorWidget::reset_selection_and_push_undo()
 {
     auto selection = m_glyph_map_widget->selection().normalized();
@@ -749,7 +767,7 @@ void FontEditorWidget::reset_selection_and_push_undo()
         m_glyph_map_widget->set_selection(start, 1);
         m_glyph_map_widget->update();
     }
-    m_undo_stack->push(make<SelectionUndoCommand>(*m_undo_selection));
+    push_undo();
 }
 
 void FontEditorWidget::undo()
@@ -963,7 +981,7 @@ void FontEditorWidget::paste_glyphs()
     auto selection = m_glyph_map_widget->selection().normalized();
     auto range_bound_glyph_count = min(glyph_count, 1 + m_range.last - selection.start());
     m_undo_selection->set_size(range_bound_glyph_count);
-    m_undo_stack->push(make<SelectionUndoCommand>(*m_undo_selection));
+    push_undo();
 
     size_t bytes_per_glyph = Gfx::GlyphBitmap::bytes_per_row() * edited_font().glyph_height();
     size_t bytes_per_copied_glyph = Gfx::GlyphBitmap::bytes_per_row() * height;
@@ -993,7 +1011,7 @@ void FontEditorWidget::paste_glyphs()
 
 void FontEditorWidget::delete_selected_glyphs()
 {
-    m_undo_stack->push(make<SelectionUndoCommand>(*m_undo_selection));
+    push_undo();
 
     auto selection = m_glyph_map_widget->selection().normalized();
     size_t bytes_per_glyph = Gfx::GlyphBitmap::bytes_per_row() * m_edited_font->glyph_height();
diff --git a/Userland/Applications/FontEditor/FontEditor.h b/Userland/Applications/FontEditor/FontEditor.h
index a23eb844c7..b049331c70 100644
--- a/Userland/Applications/FontEditor/FontEditor.h
+++ b/Userland/Applications/FontEditor/FontEditor.h
@@ -75,6 +75,7 @@ private:
     void paste_glyphs();
     void delete_selected_glyphs();
 
+    void push_undo();
     void reset_selection_and_push_undo();
 
     RefPtr<Gfx::BitmapFont> m_edited_font;
diff --git a/Userland/Applications/FontEditor/UndoSelection.h b/Userland/Applications/FontEditor/UndoSelection.h
index f6fa963ad6..6965c013d7 100644
--- a/Userland/Applications/FontEditor/UndoSelection.h
+++ b/Userland/Applications/FontEditor/UndoSelection.h
@@ -19,14 +19,14 @@ public:
         , m_font(font)
     {
     }
-    NonnullRefPtr<UndoSelection> save_state()
+    ErrorOr<NonnullRefPtr<UndoSelection>> save_state()
     {
-        auto state = adopt_ref(*new UndoSelection(m_start, m_size, m_active_glyph, *m_font));
+        auto state = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) UndoSelection(m_start, m_size, m_active_glyph, *m_font)));
         size_t bytes_per_glyph = Gfx::GlyphBitmap::bytes_per_row() * font().glyph_height();
         auto* rows = font().rows() + m_start * bytes_per_glyph;
         auto* widths = font().widths() + m_start;
-        state->m_data.append(&rows[0], bytes_per_glyph * m_size);
-        state->m_data.append(&widths[0], m_size);
+        TRY(state->m_data.try_append(&rows[0], bytes_per_glyph * m_size));
+        TRY(state->m_data.try_append(&widths[0], m_size));
         return state;
     }
     void restore_state(UndoSelection const& state)
@@ -61,20 +61,29 @@ private:
 
 class SelectionUndoCommand : public GUI::Command {
 public:
-    SelectionUndoCommand(UndoSelection& selection)
-        : m_undo_state(selection.save_state())
+    SelectionUndoCommand(UndoSelection& selection, NonnullRefPtr<UndoSelection> undo_state)
+        : m_undo_state(undo_state)
         , m_undo_selection(selection)
     {
     }
     virtual void undo() override
     {
-        if (!m_redo_state)
-            m_redo_state = m_undo_state->save_state();
+        if (!m_redo_state) {
+            if (auto maybe_state = m_undo_state->save_state(); !maybe_state.is_error()) {
+                auto state = maybe_state.release_value();
+                m_redo_state = move(state);
+            } else {
+                warnln("Failed to save redo state: {}", maybe_state.error());
+            }
+        }
         m_undo_selection.restore_state(*m_undo_state);
     }
     virtual void redo() override
     {
-        m_undo_selection.restore_state(*m_redo_state);
+        if (m_redo_state)
+            m_undo_selection.restore_state(*m_redo_state);
+        else
+            warnln("Failed to restore state");
     }
 
 private: