Implement bootstrapping auto layout

Headers/AppKit/NSLayoutConstraint.h

@@ -30,6 +30,7 @@
 #import <Foundation/NSKeyedArchiver.h>
 #import <AppKit/NSLayoutAnchor.h>
 #import <AppKit/NSView.h>
+#import <AppKit/NSWindow.h>
 
 @class NSControl, NSAnimation, NSArray, NSMutableArray, NSDictionary;
 
@@ -183,6 +184,14 @@ APPKIT_EXPORT_CLASS
 
 @end
 
+@interface NSWindow (NSConstraintBasedLayoutCoreMethods)
+
+- (void) _bootstrapAutoLayout;
+
+- (void) layoutIfNeeded;
+
+@end
+
 #if	defined(__cplusplus)
 }
 #endif

Headers/AppKit/NSView.h

@@ -53,6 +53,7 @@
 @class NSScrollView;
 @class NSView;
 @class NSWindow;
+@class GSAutoLayoutEngine;
 
 typedef NSInteger NSTrackingRectTag;
 typedef NSInteger NSToolTipTag;
@@ -186,6 +187,7 @@ PACKAGE_SCOPE
   NSUInteger _autoresizingMask;
   NSFocusRingType _focusRingType;
   NSRect _autoresizingFrameError;
+  GSAutoLayoutEngine *_layoutEngine;
 }
 
 /*

Source/GNUmakefile

@@ -356,6 +356,7 @@ GSXibLoading.m \
 GSXibKeyedUnarchiver.m \
 GSXib5KeyedUnarchiver.m \
 GSHelpAttachment.m \
+GSAutoLayoutEngine.m \
 GSAutoLayoutVFLParser.m
 
 # Turn off NSMenuItem warning that NSMenuItem conforms to <NSObject>,
@@ -671,7 +672,8 @@ GSXibElement.h \
 GSXibLoading.h \
 GSXibKeyedUnarchiver.h \
 GSHelpAttachment.h \
-GSAutoLayoutVFLParser.h
+GSAutoLayoutVFLParser.h \
+GSAutoLayoutEngine.h
 
 libgnustep-gui_HEADER_FILES = ${GUI_HEADERS}
 

Source/GSAutoLayoutEngine.h

@@ -0,0 +1,48 @@
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+   
+   By: Benjamin Johnson
+   Date: 28-2-2023
+   This file is part of the GNUstep Library.
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+   
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110 USA.
+*/
+
+#import "AppKit/NSLayoutConstraint.h"
+#import <Foundation/Foundation.h>
+
+@class NSView;
+@class NSLayoutConstraint;
+
+#ifndef _GS_AUTO_LAYOUT_ENGINE_H
+#define _GS_AUTO_LAYOUT_ENGINE_H
+
+@interface GSAutoLayoutEngine : NSObject
+
+- (void) addConstraint: (NSLayoutConstraint *)constraint;
+
+- (void) addConstraints: (NSArray *)constraints;
+
+- (void) removeConstraint: (NSLayoutConstraint *)constraint;
+
+- (void) removeConstraints: (NSArray *)constraints;
+
+- (NSRect) alignmentRectForView: (NSView *)view;
+
+- (NSArray *) constraintsForView: (NSView *)view;
+
+@end
+
+#endif

Source/GSAutoLayoutEngine.m

@@ -0,0 +1,60 @@
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+   
+   By: Benjamin Johnson
+   Date: 28-2-2023
+   This file is part of the GNUstep Library.
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+   
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110 USA.
+*/
+
+#import "GSAutoLayoutEngine.h"
+#include "AppKit/NSLayoutConstraint.h"
+
+@implementation GSAutoLayoutEngine
+
+- (void) addConstraint: (NSLayoutConstraint *)constraint
+{
+  // FIXME Add constraint to solver
+}
+
+- (void) addConstraints: (NSArray *)constraints
+{
+  // FIXME Add constraints to solver
+}
+
+- (void) removeConstraint: (NSLayoutConstraint *)constraint
+{
+  // FIXME Remove constraint from solver
+}
+
+- (void) removeConstraints: (NSArray *)constraints
+{
+  // FIXME Remove constraints from solver
+}
+
+- (NSRect) alignmentRectForView: (NSView *)view
+{
+  // FIXME Get alignment rect for view from solver
+  return NSMakeRect (0, 0, 0, 0);
+}
+
+- (NSArray *) constraintsForView: (NSView *)view
+{
+  // FIXME Get constraints for view
+  return [NSArray array];
+}
+
+@end

Source/NSLayoutConstraint.m

@@ -36,6 +36,7 @@
 #import "NSAutoresizingMaskLayoutConstraint.h" 
 #import "GSFastEnumeration.h"
 #import "GSAutoLayoutVFLParser.h"
+#import "GSAutoLayoutEngine.h"
 
 static NSMutableArray *activeConstraints = nil;
 // static NSNotificationCenter *nc = nil;
@@ -652,16 +653,92 @@ static NSMutableArray *activeConstraints = nil;
 
 @implementation NSView (NSConstraintBasedLayoutInstallingConstraints)
 
+- (void) _bootstrapAutoLayout
+{
+  if ([self window])
+    {
+      [[self window] _bootstrapAutoLayout];
+    }
+  else
+    {
+      [self _initializeLayoutEngine];
+    }
+}
+
 - (void) addConstraint: (NSLayoutConstraint *)constraint
 {
-  // FIXME: Implement adding constraint to layout engine
+  if (![self _layoutEngine])
+    {
+      [self _bootstrapAutoLayout];
+    }
+
+  [[self _layoutEngine] addConstraint: constraint];
 }
 
 - (void) addConstraints: (NSArray*)constraints
 {
-  FOR_IN (NSLayoutConstraint*, constraint, constraints)
+  if (![self _layoutEngine])
-    [self addConstraint: constraint];
+    {
-  END_FOR_IN (constraints);
+      [self _bootstrapAutoLayout];
+    }
+
+  [[self _layoutEngine] addConstraints: constraints];
+}
+
+- (void) removeConstraint: (NSLayoutConstraint *)constraint
+{
+  if (![self _layoutEngine])
+    {
+      return;
+    }
+
+  [[self _layoutEngine] removeConstraint: constraint];
+}
+
+- (void) removeConstraints: (NSArray *)constraints
+{
+  if (![self _layoutEngine])
+    {
+      return;
+    }
+
+  [[self _layoutEngine] removeConstraints: constraints];
+}
+
+- (NSArray*) constraints
+{
+  GSAutoLayoutEngine *engine = [self _layoutEngine];
+  if (!engine)
+    {
+      return [NSArray array];
+    }
+
+  return [engine constraintsForView: self];
+}
+
+- (void) _initializeLayoutEngine
+{
+  [self _setLayoutEngine: [[GSAutoLayoutEngine alloc] init]];
 }
 
 @end
+
+@implementation NSWindow (NSConstraintBasedLayoutCoreMethods)
+
+- (void) layoutIfNeeded
+{
+  [self updateConstraintsIfNeeded];
+  [[self contentView] _layoutViewAndSubViews];
+}
+
+- (void) updateConstraintsIfNeeded
+{
+  [[self contentView] updateConstraintsForSubtreeIfNeeded];
+}
+
+- (void) _bootstrapAutoLayout
+{
+  [[[self contentView] superview] _initializeLayoutEngine];
+}
+
+@end 

Source/NSView.m

@@ -79,6 +79,7 @@
 #import "GSBindingHelpers.h"
 #import "GSFastEnumeration.h"
 #import "GSGuiPrivate.h"
+#import "GSAutoLayoutEngine.h"
 #import "NSViewPrivate.h"
 
 /*
@@ -635,7 +636,8 @@ GSSetDragTypes(NSView* obj, NSArray *types)
 
   _needsUpdateConstraints = YES;
   _translatesAutoresizingMaskIntoConstraints = YES;
-  
+  _layoutEngine = nil;
+
   return self;
 }
 
@@ -768,6 +770,11 @@ GSSetDragTypes(NSView* obj, NSArray *types)
   [self unregisterDraggedTypes];
   [self releaseGState];
 
+  if (_layoutEngine && !_super_view)
+    {
+      RELEASE(_layoutEngine);
+    }
+
   [super dealloc];
 }
 
@@ -826,6 +833,8 @@ GSSetDragTypes(NSView* obj, NSArray *types)
       index += 1;
     }
 
+  [aView _setLayoutEngine: [self _layoutEngine]];
+
   [aView _viewWillMoveToWindow: _window];
   [aView _viewWillMoveToSuperview: self];
   [aView setNextResponder: self];
@@ -5140,7 +5149,17 @@ static NSView* findByTag(NSView *view, NSInteger aTag, NSUInteger *level)
 
 - (void) layout
 {
-  // FIXME: Implement asking layout engine for the alignment rect of each subview and set the alignment rect of each sub view
+  if (![self _layoutEngine])
+    {
+      return;
+    }
+
+  NSArray *subviews = [self subviews];
+  FOR_IN (NSView *, subview, subviews)
+    NSRect subviewAlignmentRect =
+        [[self _layoutEngine] alignmentRectForView: subview];
+    [subview setFrame: subviewAlignmentRect];
+  END_FOR_IN (subviews);
 }
 
 - (void) layoutSubtreeIfNeeded
@@ -5149,20 +5168,6 @@ static NSView* findByTag(NSView *view, NSInteger aTag, NSUInteger *level)
   [self _layoutViewAndSubViews];
 }
 
-- (void) _layoutViewAndSubViews
-{
-  if (_needsLayout)
-    {
-      [self layout];
-      _needsLayout = NO;
-    }
-
-  NSArray *subviews = [self subviews];
-  FOR_IN (NSView *, subview, subviews)
-    [subview _layoutViewAndSubViews];
-  END_FOR_IN (subviews);
-}
-
 - (void) setNeedsLayout: (BOOL) needsLayout
 {
   if (!needsLayout)
@@ -5212,6 +5217,35 @@ static NSView* findByTag(NSView *view, NSInteger aTag, NSUInteger *level)
   _needsUpdateConstraints = needsUpdateConstraints;
 }
 
+- (void) _layoutViewAndSubViews
+{
+  if (_needsLayout)
+    {
+      [self layout];
+      _needsLayout = NO;
+    }
+
+  NSArray *subviews = [self subviews];
+  FOR_IN (NSView *, subview, subviews)
+    [subview _layoutViewAndSubViews];
+  END_FOR_IN (subviews);
+}
+
+- (GSAutoLayoutEngine*) _layoutEngine
+{  
+  return _layoutEngine;
+}
+
+- (void) _setLayoutEngine: (GSAutoLayoutEngine *)engine
+{
+  _layoutEngine = engine;
+
+  NSArray *subviews = [self subviews];
+  FOR_IN (NSView *, subview, subviews)
+    [subview _setLayoutEngine: engine];
+  END_FOR_IN (subviews);
+}
+
 @end
 
 @implementation NSView (__NSViewPrivateMethods__)

Source/NSViewPrivate.h

@@ -42,6 +42,12 @@
 
 - (void) _setNeedsUpdateConstraints: (BOOL)needsUpdateConstraints;
 
+- (void) _layoutViewAndSubViews;
+
+- (GSAutoLayoutEngine*) _layoutEngine;
+
+- (void) _setLayoutEngine: (GSAutoLayoutEngine*)engine;
+
 @end
 
 #endif // _GNUstep_H_NSViewPrivate