Redo working

src/text_editor/layout.cpp

@@ -20,7 +20,8 @@ struct HistoryEntry {
 };
 
 struct History {
-    Array<HistoryEntry> entries;
+    Array<HistoryEntry> undo_stack;
+    Array<HistoryEntry> redo_stack;
     int                 debug_edit_phase;
 };
 
@@ -287,49 +288,19 @@ void MergeCursors(Window *window) {
             new_cursors.add(it);
         }
     }
+    Assert(new_cursors.len <= window->cursors.len);
     window->cursors.dealloc();
     window->cursors = new_cursors;
 }
 
-void UndoEdit(Window *window) {
+void SaveHistoryBeforeMergeCursor(Window *window, Array<HistoryEntry> *stack) {
-    if (window->history.entries.len <= 0) return;
+    HistoryEntry *entry         = stack->alloc();
-
-    HistoryEntry entry = window->history.entries.pop();
-    _ApplyEdits(&window->buffer, entry.edits);
-
-    window->cursors.dealloc();
-    window->cursors = entry.cursors;
-
     Allocator     sys_allocator = GetSystemAllocator();
-    For(entry.edits) Dealloc(sys_allocator, &it.string.data);
-    entry.edits.dealloc();
-
-    // Generate layout
-    Clear(&window->layout_arena);
-    window->layout = CalculateLayout(&window->layout_arena, window->buffer, window->font, window->font_size, window->font_spacing);
-}
-
-void BeforeEdit(Window *window) {
-    Assert(window->history.debug_edit_phase == 0);
-    window->history.debug_edit_phase += 1;
-
-    {
-        History      &h             = window->history;
-        HistoryEntry *entry         = h.entries.alloc();
-        Allocator     sys_allocator = GetSystemAllocator();
-        Assert(window->cursors.len);
     entry->cursors              = window->cursors.tight_copy(sys_allocator);
-    }
-
-    MergeCursors(window);
 }
 
-void ApplyEdits(Window *window, Array<Edit> edits) {
+void SaveHistoryBeforeApplyEdits(Window *window, Array<HistoryEntry> *stack, Array<Edit> edits) {
-    Assert(window->history.debug_edit_phase == 1);
+    HistoryEntry *entry         = stack->last();
-    window->history.debug_edit_phase += 1;
-
-    {
-        HistoryEntry *entry         = window->history.entries.last();
     Allocator     sys_allocator = GetSystemAllocator();
     entry->edits                = edits.tight_copy(sys_allocator);
 
@@ -359,8 +330,68 @@ void ApplyEdits(Window *window, Array<Edit> edits) {
             }
         }
     }
-    }
+}
 
+void RedoEdit(Window *window) {
+    if (window->history.redo_stack.len <= 0) return;
+
+    HistoryEntry entry = window->history.redo_stack.pop();
+
+    SaveHistoryBeforeMergeCursor(window, &window->history.undo_stack);
+    SaveHistoryBeforeApplyEdits(window, &window->history.undo_stack, entry.edits);
+    _ApplyEdits(&window->buffer, entry.edits);
+
+    window->cursors.dealloc();
+    window->cursors = entry.cursors;
+
+    Allocator sys_allocator = GetSystemAllocator();
+    For(entry.edits) Dealloc(sys_allocator, &it.string.data);
+    entry.edits.dealloc();
+
+    // Generate layout
+    Clear(&window->layout_arena);
+    window->layout = CalculateLayout(&window->layout_arena, window->buffer, window->font, window->font_size, window->font_spacing);
+}
+
+void UndoEdit(Window *window) {
+    if (window->history.undo_stack.len <= 0) return;
+
+    HistoryEntry entry = window->history.undo_stack.pop();
+
+    SaveHistoryBeforeMergeCursor(window, &window->history.redo_stack);
+    SaveHistoryBeforeApplyEdits(window, &window->history.redo_stack, entry.edits);
+    _ApplyEdits(&window->buffer, entry.edits);
+
+    window->cursors.dealloc();
+    window->cursors = entry.cursors;
+
+    Allocator sys_allocator = GetSystemAllocator();
+    For(entry.edits) Dealloc(sys_allocator, &it.string.data);
+    entry.edits.dealloc();
+
+    // Generate layout
+    Clear(&window->layout_arena);
+    window->layout = CalculateLayout(&window->layout_arena, window->buffer, window->font, window->font_size, window->font_spacing);
+}
+
+void BeforeEdit(Window *window) {
+    Assert(window->history.debug_edit_phase == 0);
+    window->history.debug_edit_phase += 1;
+    Assert(window->cursors.len);
+    SaveHistoryBeforeMergeCursor(window, &window->history.undo_stack);
+    For(window->history.redo_stack) {
+        it.cursors.dealloc();
+        ForItem(edit, it.edits) Dealloc(it.edits.allocator, &edit.string.data);
+        it.edits.dealloc();
+    }
+    window->history.redo_stack.dealloc();
+    MergeCursors(window);
+}
+
+void ApplyEdits(Window *window, Array<Edit> edits) {
+    Assert(window->history.debug_edit_phase == 1);
+    window->history.debug_edit_phase += 1;
+    SaveHistoryBeforeApplyEdits(window, &window->history.undo_stack, edits);
     _ApplyEdits(&window->buffer, edits);
 }
 
@@ -368,7 +399,7 @@ void AfterEdit(Window *window, Array<Edit> edits) {
     Assert(window->history.debug_edit_phase == 2);
     window->history.debug_edit_phase -= 2;
 
-    HistoryEntry *entry = window->history.entries.last();
+    HistoryEntry *entry = window->history.undo_stack.last();
     Assert(entry->cursors.len);
     Assert(entry->edits.len);
 

src/text_editor/main.cpp

@@ -316,9 +316,15 @@ int main() {
                 AfterEdit(focused_window, edits);
             }
 
-            if (IsKeyDown(KEY_LEFT_CONTROL) && (IsKeyPressed(KEY_Z) || IsKeyPressedRepeat(KEY_Z))) {
+            if ((IsKeyPressed(KEY_Z) || IsKeyPressedRepeat(KEY_Z))) {
+                if (IsKeyDown(KEY_LEFT_CONTROL)) {
+                    if (IsKeyDown(KEY_LEFT_SHIFT)) {
+                        RedoEdit(focused_window);
+                    } else {
                         UndoEdit(focused_window);
                     }
+                }
+            }
 
             if (IsKeyPressed(KEY_DELETE) || IsKeyPressedRepeat(KEY_DELETE)) {
                 // Select things to delete