shell/mondrian_story_shell/lib/models/surface/surface_graph.dart - topaz - Git at Google

 // Copyright 2018 The Fuchsia Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:developer' show Timeline;

 import 'package:fidl/fidl.dart';
 import 'package:fidl_fuchsia_modular/fidl.dart';
 import 'package:fidl_fuchsia_ui_views/fidl_async.dart';
 import 'package:fidl_fuchsia_ui_viewsv1token/fidl.dart';
 import 'package:fuchsia_scenic_flutter/child_view_connection.dart'
     show ChildViewConnection;
 import 'package:lib.app.dart/logging.dart';
 import 'package:lib.widgets/model.dart';
 import 'package:zircon/zircon.dart' show EventPair;

 import '../tree/spanning_tree.dart';
 import '../tree/tree.dart';
 import 'surface.dart';
 import 'surface_properties.dart';

 // Data structure to manage the relationships and relative focus of surfaces
 class SurfaceGraph extends Model {
   SurfaceGraph() {
     setupLogger(name: 'Mondrian');
   }

   SurfaceGraph.fromJson(Map<String, dynamic> json) {
     reload(json);
   }

   /// Cache of surfaces
   final Map<String, Surface> _surfaces = <String, Surface>{};

   /// Surface relationship tree
   final Tree<String> _tree = new Tree<String>(value: null);

   /// The stack of previous focusedSurfaces, most focused at end
   final List<String> _focusedSurfaces = <String>[];

   /// The stack of previous focusedSurfaces, most focused at end
   final Set<String> _dismissedSurfaces = <String>{};

   /// A mapping between surfaces that were brought in as ModuleSource::External
   /// surfaces (e.g. suggestions) and surfaces that were visually present at
   /// their introduction, in order to track where to provide a shell affordance
   /// for resummoning external surfaces that have been dismissed
   /// (surfaces are identified by ID)
   final Map<String, String> _visualAssociation = <String, String>{};

   Tree<String> get root => _tree;

   /// The node corresponding to the given id.
   Surface getNode(String id) => _surfaces[id];

   /// The last focused surface.
   Surface _lastFocusedSurface;

   /// The currently most focused [Surface]
   Surface get focused =>
       _focusedSurfaces.isEmpty ? null : _surfaces[_focusedSurfaces.last];

   /// The history of focused [Surface]s
   Iterable<Surface> get focusStack => _focusedSurfaces
       .where(_surfaces.containsKey)
       .map((String id) => _surfaces[id]);

   /// Add a [Surface] to the graph with the given parameters.
   ///
   /// Returns the surface that was added to the graph.
   Surface addSurface(
     String id,
     SurfaceProperties properties,
     String parentId,
     SurfaceRelation relation,
     String pattern,
     String placeholderColor,
   ) {
     Tree<String> node = _tree.find(id) ?? new Tree<String>(value: id);
     Tree<String> parent =
         (parentId == kNoParent) ? _tree : _tree.find(parentId);
     assert(parent != null);
     assert(relation != null);
     Surface oldSurface = _surfaces[id];
     Surface updatedSurface = new Surface(
         this, node, properties, relation, pattern, placeholderColor);
     // if this is an external surface, create an association between this and
     // the most focused surface.
     if (properties.source == ModuleSource.external$ &&
         _focusedSurfaces.isNotEmpty) {
       _visualAssociation[_focusedSurfaces.last] = id;
     }
     if (oldSurface != null) {
       // TODO (jphsiao): this is a hack to handle the adding of a surface with
       // the same view id. In this case we assume the view is going to be
       // reused.
       updatedSurface.connection = oldSurface.connection;
     }
     _surfaces[id] = updatedSurface;
     // Do not add the child again if the parent already knows about it.
     if (!parent.children.contains(node)) {
       parent.add(node);
     }

     notifyListeners();
     return updatedSurface;
   }

   /// Removes [Surface] from graph
   void removeSurface(String id) {
     if (_surfaces.keys.contains(id)) {
       Tree<String> node = _tree.find(id);
       if (node != null) {
         node.detach();
         // Remove orphaned children
         for (Tree<String> child in node.children) {
           child.detach();
           // As a temporary policy, remove child surfaces when surfaces are
           // removed. This policy will be revisited when we have a better sense
           // of what to do with orphaned children.
           _surfaces[child.value].remove();
           _focusedSurfaces.remove(child.value);
           _dismissedSurfaces.remove(child.value);
         }
         _focusedSurfaces.remove(id);
         _dismissedSurfaces.remove(id);
         _surfaces.remove(id);
         notifyListeners();
       }
     }
   }

   /// Move the surface up in the focus stack, undismissing it if needed.
   void focusSurface(String id) {
     if (!_surfaces.containsKey(id)) {
       log.warning('Invalid surface id "$id"');
       return;
     }
     _dismissedSurfaces.remove(id);
     _focusedSurfaces
       ..remove(id)
       ..add(id);

     // Also request the input focus through the child view connection.
     ChildViewConnection connection = _surfaces[id].connection;
     if (connection != null) {
       _surfaces[id].connection.requestFocus();
       _lastFocusedSurface = _surfaces[id];
       notifyListeners();
     }
   }

   /// Add a container root to the surface graph
   void addContainer(
     String id,
     SurfaceProperties properties,
     String parentId,
     SurfaceRelation relation,
     List<ContainerLayout> layouts,
   ) {
     // TODO (djurphy): collisions/pathing - partial fix if we
     // make the changes so container IDs are paths.
     log.info('addContainer: $id');
     Tree<String> node = _tree.find(id) ?? new Tree<String>(value: id);
     log.info('found or made node: $node');
     Tree<String> parent =
         (parentId == kNoParent) ? _tree : _tree.find(parentId);
     assert(parent != null);
     assert(relation != null);
     parent.add(node);
     Surface oldSurface = _surfaces[id];
     _surfaces[id] = new SurfaceContainer(
         this, node, properties, relation, '' /*pattern*/, layouts);
     oldSurface?.notifyListeners();
     log.info('_surfaces[id]: ${_surfaces[id]}');
     notifyListeners();
   }

   /// Returns the list of surfaces that would be dismissed if this surface
   /// were dismissed - e.g. as a result of dependency - including this surface
   List<String> dismissedSet(String id) {
     Surface dismissed = _surfaces[id];
     List<Surface> ancestors = dismissed.ancestors.toList();
     List<Surface> dependentTree = getDependentSpanningTree(dismissed)
         .map((Tree<Surface> t) => t.value)
         .toList()
           // TODO(djmurphy) - when codependent comes in this needs to change
           // this only removes down the tree, codependents would remove their
           // ancestors
           ..removeWhere((Surface s) => ancestors.contains(s));
     List<String> depIds =
         dependentTree.map((Surface s) => s.node.value).toList();
     return depIds;
   }

   /// Check if given surface can be dismissed
   bool canDismissSurface(String id) {
     List<String> wouldDismiss = dismissedSet(id);
     return _focusedSurfaces
         .where((String fid) => !wouldDismiss.contains(fid))
         .isNotEmpty;
   }

   /// When called surface is no longer displayed
   bool dismissSurface(String id) {
     if (!canDismissSurface(id)) {
       return false;
     }
     List<String> depIds = dismissedSet(id);
     _focusedSurfaces.removeWhere((String fid) => depIds.contains(fid));
     _dismissedSurfaces.addAll(depIds);
     notifyListeners();
     return true;
   }

   /// True if surface has been dismissed and not subsequently focused
   bool isDismissed(String id) => _dismissedSurfaces.contains(id);

   void connectView(String id, InterfaceHandle<ViewOwner> viewOwner) {
     connectViewFromViewHolderToken(
         id,
         ViewHolderToken(
             value: EventPair(viewOwner.passChannel().passHandle())));
   }

   /// Used to update a [Surface] with a live ChildViewConnection
   void connectViewFromViewHolderToken(
       String id, ViewHolderToken viewHolderToken) {
     final Surface surface = _surfaces[id];
     if (surface != null) {
       if (surface.connection != null) {
         // TODO(jphsiao): remove this hack once story shell API has been
         // change to accomodate view reusage
         return;
       }
       log.fine('connectView $surface');
       surface
         ..connection = ChildViewConnection(
           viewHolderToken,
           onAvailable: (ChildViewConnection connection) {
             Timeline.instantSync('surface available', arguments: {'id': '$id'});

             // If this surface is the last focused one, also request input focus
             if (_lastFocusedSurface == surface) {
               connection.requestFocus();
             }
             surface.notifyListeners();
           },
           onUnavailable: (ChildViewConnection connection) {
             trace('surface $id unavailable');
             surface.connection = null;
             if (_surfaces.containsValue(surface)) {
               removeSurface(id);
               notifyListeners();
             }
             // Also any existing listener
             surface.notifyListeners();
           },
         )
         ..notifyListeners();
     }
   }

   void reload(Map<String, dynamic> json) {
     List<dynamic> decodedSurfaceList = json['surfaceList'];
     for (dynamic s in decodedSurfaceList) {
       Map<String, dynamic> item = s.cast<String, dynamic>();
       Surface surface = new Surface.fromJson(item, this);

       _surfaces.putIfAbsent(surface.node.value, () {
         return surface;
       });
     }
     _surfaces.forEach((String id, Surface surface) {
       Tree<String> node = surface.node;
       if (surface.isParentRoot) {
         _tree.add(node);
       }
       if (surface.childIds != null) {
         for (String id in surface.childIds) {
           node.add(_surfaces[id].node);
         }
       }
     });
     dynamic list = json['focusStack'];
     List<String> focusStack = list.cast<String>();
     _focusedSurfaces.addAll(focusStack);
   }

   // Get the SurfaceIds of associated external surfaces
   // (surfaces originating from outside the current story)
   // that are dismissed and associated with the current Surface
   Set<String> externalSurfaces({String surfaceId}) {
     // Case1: An external child has a relationship with this surface
     // and the child has been dismissed
     Surface parent = getNode(surfaceId);
     List<Surface> externalSurfaces = parent.children.toList()
       ..retainWhere(
           (Surface s) => s.properties.source == ModuleSource.external$);
     Set<String> externalIds =
         externalSurfaces.map((Surface s) => s.node.value).toSet();
     // Case2: The focused surface has a recorded visual association with an
     // external surface
     if (_visualAssociation[surfaceId].isNotEmpty) {
       externalIds.add(_visualAssociation[surfaceId]);
     }
     return externalIds;
   }

   /// Returns the amount of [Surface]s in the graph
   int get size => _surfaces.length;

   /// The tree size includes the root node which has no surface
   int get treeSize => _tree.flatten().length;

   @override
   String toString() =>
       'Tree:\n${_tree.children.map(_toString).join('\n')}\nfocusStack length ${focusStack.length}';

   String _toString(Tree<String> node, {String prefix = ''}) {
     String nodeString = '$prefix${_surfaces[node.value]}';
     if (node.children.isNotEmpty) {
       nodeString =
           '$nodeString\n${node.children.map((Tree<String> node) => _toString(node, prefix: '$prefix  ')).join('\n')}';
     }
     return '$nodeString';
   }

   Map<String, dynamic> toJson() {
     return {
       'surfaceList': _surfaces.values.toList(),
       'focusStack': _focusedSurfaces,
       'links': [], // TODO(jphsiao): plumb through link data
     };
   }
 }
	// Copyright 2018 The Fuchsia Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:developer' show Timeline;

	import 'package:fidl/fidl.dart';
	import 'package:fidl_fuchsia_modular/fidl.dart';
	import 'package:fidl_fuchsia_ui_views/fidl_async.dart';
	import 'package:fidl_fuchsia_ui_viewsv1token/fidl.dart';
	import 'package:fuchsia_scenic_flutter/child_view_connection.dart'
	show ChildViewConnection;
	import 'package:lib.app.dart/logging.dart';
	import 'package:lib.widgets/model.dart';
	import 'package:zircon/zircon.dart' show EventPair;

	import '../tree/spanning_tree.dart';
	import '../tree/tree.dart';
	import 'surface.dart';
	import 'surface_properties.dart';

	// Data structure to manage the relationships and relative focus of surfaces
	class SurfaceGraph extends Model {
	SurfaceGraph() {
	setupLogger(name: 'Mondrian');
	}

	SurfaceGraph.fromJson(Map<String, dynamic> json) {
	reload(json);
	}

	/// Cache of surfaces
	final Map<String, Surface> _surfaces = <String, Surface>{};

	/// Surface relationship tree
	final Tree<String> _tree = new Tree<String>(value: null);

	/// The stack of previous focusedSurfaces, most focused at end
	final List<String> _focusedSurfaces = <String>[];

	/// The stack of previous focusedSurfaces, most focused at end
	final Set<String> _dismissedSurfaces = <String>{};

	/// A mapping between surfaces that were brought in as ModuleSource::External
	/// surfaces (e.g. suggestions) and surfaces that were visually present at
	/// their introduction, in order to track where to provide a shell affordance
	/// for resummoning external surfaces that have been dismissed
	/// (surfaces are identified by ID)
	final Map<String, String> _visualAssociation = <String, String>{};

	Tree<String> get root => _tree;

	/// The node corresponding to the given id.
	Surface getNode(String id) => _surfaces[id];

	/// The last focused surface.
	Surface _lastFocusedSurface;

	/// The currently most focused [Surface]
	Surface get focused =>
	_focusedSurfaces.isEmpty ? null : _surfaces[_focusedSurfaces.last];

	/// The history of focused [Surface]s
	Iterable<Surface> get focusStack => _focusedSurfaces
	.where(_surfaces.containsKey)
	.map((String id) => _surfaces[id]);

	/// Add a [Surface] to the graph with the given parameters.
	///
	/// Returns the surface that was added to the graph.
	Surface addSurface(
	String id,
	SurfaceProperties properties,
	String parentId,
	SurfaceRelation relation,
	String pattern,
	String placeholderColor,
	) {
	Tree<String> node = _tree.find(id) ?? new Tree<String>(value: id);
	Tree<String> parent =
	(parentId == kNoParent) ? _tree : _tree.find(parentId);
	assert(parent != null);
	assert(relation != null);
	Surface oldSurface = _surfaces[id];
	Surface updatedSurface = new Surface(
	this, node, properties, relation, pattern, placeholderColor);
	// if this is an external surface, create an association between this and
	// the most focused surface.
	if (properties.source == ModuleSource.external$ &&
	_focusedSurfaces.isNotEmpty) {
	_visualAssociation[_focusedSurfaces.last] = id;
	}
	if (oldSurface != null) {
	// TODO (jphsiao): this is a hack to handle the adding of a surface with
	// the same view id. In this case we assume the view is going to be
	// reused.
	updatedSurface.connection = oldSurface.connection;
	}
	_surfaces[id] = updatedSurface;
	// Do not add the child again if the parent already knows about it.
	if (!parent.children.contains(node)) {
	parent.add(node);
	}

	notifyListeners();
	return updatedSurface;
	}

	/// Removes [Surface] from graph
	void removeSurface(String id) {
	if (_surfaces.keys.contains(id)) {
	Tree<String> node = _tree.find(id);
	if (node != null) {
	node.detach();
	// Remove orphaned children
	for (Tree<String> child in node.children) {
	child.detach();
	// As a temporary policy, remove child surfaces when surfaces are
	// removed. This policy will be revisited when we have a better sense
	// of what to do with orphaned children.
	_surfaces[child.value].remove();
	_focusedSurfaces.remove(child.value);
	_dismissedSurfaces.remove(child.value);
	}
	_focusedSurfaces.remove(id);
	_dismissedSurfaces.remove(id);
	_surfaces.remove(id);
	notifyListeners();
	}
	}
	}

	/// Move the surface up in the focus stack, undismissing it if needed.
	void focusSurface(String id) {
	if (!_surfaces.containsKey(id)) {
	log.warning('Invalid surface id "$id"');
	return;
	}
	_dismissedSurfaces.remove(id);
	_focusedSurfaces
	..remove(id)
	..add(id);

	// Also request the input focus through the child view connection.
	ChildViewConnection connection = _surfaces[id].connection;
	if (connection != null) {
	_surfaces[id].connection.requestFocus();
	_lastFocusedSurface = _surfaces[id];
	notifyListeners();
	}
	}

	/// Add a container root to the surface graph
	void addContainer(
	String id,
	SurfaceProperties properties,
	String parentId,
	SurfaceRelation relation,
	List<ContainerLayout> layouts,
	) {
	// TODO (djurphy): collisions/pathing - partial fix if we
	// make the changes so container IDs are paths.
	log.info('addContainer: $id');
	Tree<String> node = _tree.find(id) ?? new Tree<String>(value: id);
	log.info('found or made node: $node');
	Tree<String> parent =
	(parentId == kNoParent) ? _tree : _tree.find(parentId);
	assert(parent != null);
	assert(relation != null);
	parent.add(node);
	Surface oldSurface = _surfaces[id];
	_surfaces[id] = new SurfaceContainer(
	this, node, properties, relation, '' /pattern/, layouts);
	oldSurface?.notifyListeners();
	log.info('_surfaces[id]: ${_surfaces[id]}');
	notifyListeners();
	}

	/// Returns the list of surfaces that would be dismissed if this surface
	/// were dismissed - e.g. as a result of dependency - including this surface
	List<String> dismissedSet(String id) {
	Surface dismissed = _surfaces[id];
	List<Surface> ancestors = dismissed.ancestors.toList();
	List<Surface> dependentTree = getDependentSpanningTree(dismissed)
	.map((Tree<Surface> t) => t.value)
	.toList()
	// TODO(djmurphy) - when codependent comes in this needs to change
	// this only removes down the tree, codependents would remove their
	// ancestors
	..removeWhere((Surface s) => ancestors.contains(s));
	List<String> depIds =
	dependentTree.map((Surface s) => s.node.value).toList();
	return depIds;
	}

	/// Check if given surface can be dismissed
	bool canDismissSurface(String id) {
	List<String> wouldDismiss = dismissedSet(id);
	return _focusedSurfaces
	.where((String fid) => !wouldDismiss.contains(fid))
	.isNotEmpty;
	}

	/// When called surface is no longer displayed
	bool dismissSurface(String id) {
	if (!canDismissSurface(id)) {
	return false;
	}
	List<String> depIds = dismissedSet(id);
	_focusedSurfaces.removeWhere((String fid) => depIds.contains(fid));
	_dismissedSurfaces.addAll(depIds);
	notifyListeners();
	return true;
	}

	/// True if surface has been dismissed and not subsequently focused
	bool isDismissed(String id) => _dismissedSurfaces.contains(id);

	void connectView(String id, InterfaceHandle<ViewOwner> viewOwner) {
	connectViewFromViewHolderToken(
	id,
	ViewHolderToken(
	value: EventPair(viewOwner.passChannel().passHandle())));
	}

	/// Used to update a [Surface] with a live ChildViewConnection
	void connectViewFromViewHolderToken(
	String id, ViewHolderToken viewHolderToken) {
	final Surface surface = _surfaces[id];
	if (surface != null) {
	if (surface.connection != null) {
	// TODO(jphsiao): remove this hack once story shell API has been
	// change to accomodate view reusage
	return;
	}
	log.fine('connectView $surface');
	surface
	..connection = ChildViewConnection(
	viewHolderToken,
	onAvailable: (ChildViewConnection connection) {
	Timeline.instantSync('surface available', arguments: {'id': '$id'});

	// If this surface is the last focused one, also request input focus
	if (_lastFocusedSurface == surface) {
	connection.requestFocus();
	}
	surface.notifyListeners();
	},
	onUnavailable: (ChildViewConnection connection) {
	trace('surface $id unavailable');
	surface.connection = null;
	if (_surfaces.containsValue(surface)) {
	removeSurface(id);
	notifyListeners();
	}
	// Also any existing listener
	surface.notifyListeners();
	},
	)
	..notifyListeners();
	}
	}

	void reload(Map<String, dynamic> json) {
	List<dynamic> decodedSurfaceList = json['surfaceList'];
	for (dynamic s in decodedSurfaceList) {
	Map<String, dynamic> item = s.cast<String, dynamic>();
	Surface surface = new Surface.fromJson(item, this);

	_surfaces.putIfAbsent(surface.node.value, () {
	return surface;
	});
	}
	_surfaces.forEach((String id, Surface surface) {
	Tree<String> node = surface.node;
	if (surface.isParentRoot) {
	_tree.add(node);
	}
	if (surface.childIds != null) {
	for (String id in surface.childIds) {
	node.add(_surfaces[id].node);
	}
	}
	});
	dynamic list = json['focusStack'];
	List<String> focusStack = list.cast<String>();
	_focusedSurfaces.addAll(focusStack);
	}

	// Get the SurfaceIds of associated external surfaces
	// (surfaces originating from outside the current story)
	// that are dismissed and associated with the current Surface
	Set<String> externalSurfaces({String surfaceId}) {
	// Case1: An external child has a relationship with this surface
	// and the child has been dismissed
	Surface parent = getNode(surfaceId);
	List<Surface> externalSurfaces = parent.children.toList()
	..retainWhere(
	(Surface s) => s.properties.source == ModuleSource.external$);
	Set<String> externalIds =
	externalSurfaces.map((Surface s) => s.node.value).toSet();
	// Case2: The focused surface has a recorded visual association with an
	// external surface
	if (_visualAssociation[surfaceId].isNotEmpty) {
	externalIds.add(_visualAssociation[surfaceId]);
	}
	return externalIds;
	}

	/// Returns the amount of [Surface]s in the graph
	int get size => _surfaces.length;

	/// The tree size includes the root node which has no surface
	int get treeSize => _tree.flatten().length;

	@override
	String toString() =>
	'Tree:\n${_tree.children.map(_toString).join('\n')}\nfocusStack length ${focusStack.length}';

	String _toString(Tree<String> node, {String prefix = ''}) {
	String nodeString = '$prefix${_surfaces[node.value]}';
	if (node.children.isNotEmpty) {
	nodeString =
	'$nodeString\n${node.children.map((Tree<String> node) => _toString(node, prefix: '$prefix ')).join('\n')}';
	}
	return '$nodeString';
	}

	Map<String, dynamic> toJson() {
	return {
	'surfaceList': _surfaces.values.toList(),
	'focusStack': _focusedSurfaces,
	'links': [], // TODO(jphsiao): plumb through link data
	};
	}
	}