Trying to add undo

src/text_editor/buffer.cpp

@@ -225,7 +225,7 @@ void MergeSort(int64_t Count, Edit *First, Edit *Temp) {
     }
 }
 
-void ApplyEdits(Buffer *buffer, Array<Edit> edits) {
+void _ApplyEdits(Buffer *buffer, Array<Edit> edits) {
     Scratch scratch((Arena *)buffer->allocator.object);
     Assert(buffer->data[0]);
     Assert(buffer->allocator.proc);

src/text_editor/event_recording.cpp

@@ -101,7 +101,7 @@ void EventRecording_SimulateGetCharPressed(Window *focused_window) {
             For(focused_window->cursors) {
                 AddEdit(&edits, it.range, string);
             }
-            ApplyEdits(&focused_window->buffer, edits);
+            ApplyEdits(focused_window, edits);
             AfterEdit(focused_window, edits);
         }
     }

src/text_editor/layout.cpp

@@ -14,6 +14,16 @@ struct Layout {
     Vec2             buffer_world_pixel_size;
 };
 
+struct HistoryEntry {
+    Array<Cursor> cursors;
+    Array<Edit>   edits;
+};
+
+struct History {
+    Array<HistoryEntry> entries;
+    int                 debug_edit_phase;
+};
+
 struct Window {
     Font  font;
     float font_size;
@@ -25,6 +35,7 @@ struct Window {
     Cursor        main_cursor_begin_frame;
     Array<Cursor> cursors;
     Buffer        buffer;
+    History       history;
 
     Arena  layout_arena;
     Layout layout;
@@ -246,7 +257,7 @@ Array<LayoutColumn> CalculateVisibleColumns(Arena *arena, Window &window) {
     return r;
 }
 
-void BeforeEdit(Window *window) {
+void MergeCursors(Window *window) {
     Scratch scratch;
     // Merge cursors that overlap, this needs to be handled before any edits to
     // make sure overlapping edits won't happen.
@@ -280,7 +291,67 @@ void BeforeEdit(Window *window) {
     window->cursors = new_cursors;
 }
 
+void UndoEdit(Window *window) {
+    if (window->history.entries.len <= 0) return;
+
+    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) {
+    Assert(window->history.debug_edit_phase == 1);
+    window->history.debug_edit_phase += 1;
+
+    {
+        HistoryEntry *entry         = window->history.entries.last();
+        Allocator     sys_allocator = GetSystemAllocator();
+        entry->edits                = edits.tight_copy(sys_allocator);
+        For(entry->edits) {
+            // Need to compile reverse edits
+            Range  new_range = {it.range.min, it.range.min + it.string.len};
+            String string    = GetString(window->buffer, it.range);
+            it.string        = Copy(sys_allocator, string);
+            it.range         = new_range;
+        }
+    }
+
+    _ApplyEdits(&window->buffer, edits);
+}
+
 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();
+    Assert(entry->cursors.len);
+    Assert(entry->edits.len);
+
     // Offset all cursors by edits
     ForItem(edit, edits) {
         int64_t remove_size = GetRangeSize(edit.range);
@@ -308,6 +379,7 @@ void AfterEdit(Window *window, Array<Edit> edits) {
     // Make sure all cursors are in range
     For(window->cursors) it.range = Clamp(window->buffer, it.range);
 
+    // Generate layout
     Clear(&window->layout_arena);
     window->layout = CalculateLayout(&window->layout_arena, window->buffer, window->font, window->font_size, window->font_spacing);
 }

src/text_editor/main.cpp

@@ -63,27 +63,26 @@ int main() {
         window.font_size = font_size;
         window.font_spacing;
         InitArena(&window.layout_arena);
-
         InitBuffer(GetSystemAllocator(), &window.buffer);
-        if (1) {
-            // Array<Edit> edits = {FrameArena};
-            // AddEdit(&edits, GetEnd(window.buffer), Format(FrameArena, "line number: 1"));
-            // ApplyEdits(&window.buffer, edits);
-            for (int i = 0; i < 50; i += 1) {
-                Array<Edit> edits = {FrameArena};
-                AddEdit(&edits, GetEnd(window.buffer), Format(FrameArena, "line number: %d\n", i));
-                ApplyEdits(&window.buffer, edits);
-            }
-        }
 
         window.cursors.allocator = GetSystemAllocator();
         window.cursors.add({});
-        AfterEdit(&window, {});
 
+        if (1) {
+            for (int i = 0; i < 50; i += 1) {
+                BeforeEdit(&window);
+                Array<Edit> edits = {FrameArena};
+                AddEdit(&edits, GetEnd(window.buffer), Format(FrameArena, "line number: %d\n", i));
+                ApplyEdits(&window, edits);
+                AfterEdit(&window, edits);
+            }
+        }
+
+        *window.cursors.last() = {};
         windows.add(window);
     }
 
-    // EnableEventWaiting();
+    int64_t frame = -1;
     InitEventRecording();
     while (!WindowShouldClose()) {
         For(windows) {
@@ -91,6 +90,9 @@ int main() {
             it.main_cursor_begin_frame = it.cursors[0];
         }
 
+        frame += 1;
+        Dbg("%lld", (long long)frame);
+
         UpdateEventRecording();
 
         {
@@ -100,7 +102,7 @@ int main() {
             focused_window->scroll.y -= mouse_wheel;
             focused_window->scroll.y = ClampBottom(focused_window->scroll.y, 0.f);
 
-            BeforeEdit(focused_window); // Merge cursors
+            MergeCursors(focused_window);
             if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyPressed(KEY_A)) {
                 focused_window->cursors.clear();
                 focused_window->cursors.add(MakeCursor(0, focused_window->buffer.len));
@@ -167,7 +169,7 @@ int main() {
                         cursors_to_add.add({front, front});
                     }
                     For(cursors_to_add) focused_window->cursors.add(it);
-                    BeforeEdit(focused_window);                                      // Merge cursors
+                    MergeCursors(focused_window);
                 } else if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyDown(KEY_LEFT_ALT)) { // Default in VSCode seems to be Shift + Alt + down
                     BeforeEdit(focused_window);
                     Array<Edit> edits = {FrameArena};
@@ -177,7 +179,7 @@ int main() {
                         String  string = GetString(focused_window->buffer, line.range);
                         AddEdit(&edits, {line.range.max, line.range.max}, string);
                     }
-                    ApplyEdits(&focused_window->buffer, edits);
+                    ApplyEdits(focused_window, edits);
                     AfterEdit(focused_window, edits);
                     For(focused_window->cursors) {
                         it.range.max = it.range.min = MoveDown(focused_window->buffer, it.range.min);
@@ -204,7 +206,7 @@ int main() {
                         cursors_to_add.add({front, front});
                     }
                     For(cursors_to_add) focused_window->cursors.add(it);
-                    BeforeEdit(focused_window);                                      // Merge cursors
+                    MergeCursors(focused_window);
                 } else if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyDown(KEY_LEFT_ALT)) { // Default in VSCode seems to be Shift + Alt + up
                     BeforeEdit(focused_window);
                     Array<Edit> edits = {FrameArena};
@@ -214,7 +216,7 @@ int main() {
                         String  string = GetString(focused_window->buffer, line.range);
                         AddEdit(&edits, {line.range.min, line.range.min}, string);
                     }
-                    ApplyEdits(&focused_window->buffer, edits);
+                    ApplyEdits(focused_window, edits);
                     AfterEdit(focused_window, edits);
                     For(focused_window->cursors) {
                         it.range.max = it.range.min = MoveUp(focused_window->buffer, it.range.min);
@@ -240,7 +242,7 @@ int main() {
                 if (Seek(to_seek, needle, &found_index, SeekFlag_IgnoreCase)) {
                     found_index += cursor.range.max;
                     focused_window->cursors.add(MakeCursor(found_index + needle.len, found_index));
-                    BeforeEdit(focused_window); // Merge cursors
+                    MergeCursors(focused_window);
                 }
             }
 
@@ -288,7 +290,7 @@ int main() {
                 For(focused_window->cursors) {
                     AddEdit(&edits, it.range, string);
                 }
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
             if (IsKeyDown(KEY_LEFT_CONTROL) && (IsKeyPressed(KEY_X) || IsKeyPressedRepeat(KEY_X))) {
@@ -310,10 +312,14 @@ int main() {
                 }
                 String to_save = Merge(FrameArena, strings, "\n");
                 SetClipboardText(to_save.data);
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
 
+            if (IsKeyDown(KEY_LEFT_CONTROL) && (IsKeyPressed(KEY_Z) || IsKeyPressedRepeat(KEY_Z))) {
+                UndoEdit(focused_window);
+            }
+
             if (IsKeyPressed(KEY_DELETE) || IsKeyPressedRepeat(KEY_DELETE)) {
                 // Select things to delete
                 For(focused_window->cursors) {
@@ -334,7 +340,7 @@ int main() {
                 Array<Edit> edits  = {FrameArena};
                 String      string = {};
                 For(focused_window->cursors) AddEdit(&edits, it.range, string);
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
 
@@ -358,7 +364,7 @@ int main() {
                 Array<Edit> edits  = {FrameArena};
                 String      string = {};
                 For(focused_window->cursors) AddEdit(&edits, it.range, string);
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
 
@@ -366,7 +372,7 @@ int main() {
                 BeforeEdit(focused_window);
                 Array<Edit> edits = {FrameArena};
                 For(focused_window->cursors) AddEdit(&edits, it.range, "    ");
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
 
@@ -382,7 +388,7 @@ int main() {
                 BeforeEdit(focused_window);
                 Array<Edit> edits = {FrameArena};
                 For(focused_window->cursors) AddEdit(&edits, it.range, "\n");
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
 
@@ -402,7 +408,7 @@ int main() {
                 For(focused_window->cursors) {
                     AddEdit(&edits, it.range, string);
                 }
-                ApplyEdits(&focused_window->buffer, edits);
+                ApplyEdits(focused_window, edits);
                 AfterEdit(focused_window, edits);
             }
             EventRecording_SimulateGetCharPressed(focused_window);
@@ -457,7 +463,7 @@ int main() {
                             window.cursors.clear();
                         }
                         window.cursors.add({col->pos, col->pos});
-                        BeforeEdit(&window); // Merge cursors
+                        MergeCursors(&window);
                         window.mouse_selecting = true;
                     }
 
@@ -572,6 +578,14 @@ int main() {
 
         Dbg_Draw();
         EventRecording_Draw();
+
+        Window *focused_window = &windows[0];
+        if (focused_window->mouse_selecting || EventPlaying) {
+            DisableEventWaiting();
+        } else {
+            EnableEventWaiting();
+        }
+
         EndDrawing();
     }
 }