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Merged
merged 3 commits into from
Apr 19, 2025
Merged

New fix for hibernation bug w/out hacks #160

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b7d9e2f
remove all hacks
SirRufoApr 17, 2025
292d7c7
remove all hacks
SirRufoApr 17, 2025
9c7423c
manage IView references in list
SirRufoApr 17, 2025
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20 changes: 0 additions & 20 deletions Src/FmMain.pas
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Original file line numberDiff line numberDiff line change
Expand Up@@ -522,12 +522,6 @@ TMainForm = class(THelpAwareForm)
/// <summary>Object that manages favourites.</summary>
fFavouritesMgr: TFavouritesManager;

/// <summary>Handles the <c>WM_POWERBROADCAST</c> messages to detect and
/// respond to hibernation messages.</summary>
/// <remarks>!! HACK necessary as part of the fix for an obscure bug. See
/// https://.com/delphidabbler/codesnip/issues/70</remarks>
procedure WMPowerBroadcast(var Msg: TMessage); message WM_POWERBROADCAST;

/// <summary>Displays view item given by TViewItemAction instance
/// referenced by Sender and adds to history list.</summary>
procedure ActViewItemExecute(Sender: TObject);
Expand DownExpand Up@@ -1586,19 +1580,5 @@ procedure TMainForm.splitVertCanResize(Sender: TObject;
Accept := False;
end;

procedure TMainForm.WMPowerBroadcast(var Msg: TMessage);
begin
// !! HACK
// Sometimes when the computer is resumed from hibernation the tree view in
// the overview frame is destroyed and recreated by Windows. Unfortunately the
// IView instances associated with the recreated tree nodes are lost.
// Attempting to read those (now nil) IView instances was resulting in an
// access violation.
case Msg.WParam of
PBT_APMSUSPEND:
fMainDisplayMgr._HACK_PrepareForHibernate;
end;
end;

end.

4 changes: 2 additions & 2 deletions Src/FrOverview.dfm
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@@ -1,9 +1,9 @@
inherited OverviewFrame: TOverviewFrame
inherited pnlTitle: TPanel
inherited lblTitle: TLabel
Width = 54
Width = 53
Caption = 'Overview'
ExplicitWidth = 54
ExplicitWidth = 53
end
object tbarOverview: TToolBar
Left = 224
Expand Down
58 changes: 5 additions & 53 deletions Src/FrOverview.pas
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Original file line numberDiff line numberDiff line change
Expand Up@@ -18,6 +18,7 @@ interface

uses
// Delphi
Generics.Collections,
ComCtrls, Controls, Classes, Windows, ExtCtrls, StdCtrls, ToolWin, Menus,
// Project
DB.USnippet, FrTitled, IntfFrameMgrs, IntfNotifier, UCommandBars,
Expand All@@ -26,29 +27,6 @@ interface

type

// !! HACK
// Horrible hack to expose CreateWnd for overiding TTreeView.CreateWnd for the
// existing TTreeView component of TOverviewFrame. The hack avoids having to
// remove the component and replacing it with a descendant class that is
// manually constructed at run time.
// This is here to enable the tree view to be recreated with correctly
// instantiated TViewItemTreeNode nodes after Windows recreates the tree
// behind the scenes after resuming from hibernation.
// I am deeply ashamed of this hack.
TTreeView = class(ComCtrls.TTreeView)
strict private
var
_HACK_fOnAfterCreateNilViews: TNotifyEvent;
protected
procedure CreateWnd; override;
public
/// <summary>!! HACK. Event triggered after the inherited CreateWnd is
/// called. Only called if the tree view has nil references to IView
/// objects.</summary>
property _HACK_OnAfterCreateNilViews: TNotifyEvent
read _HACK_fOnAfterCreateNilViews write _HACK_fOnAfterCreateNilViews;
end;

{
TOverviewFrame:
Titled frame that displays lists of snippets grouped in various ways and
Expand DownExpand Up@@ -111,6 +89,7 @@ TTVDraw = class(TSnippetsTVDraw)
end;

var
fViewStore : TList<IView>; // Stores the references of the Views
fTVDraw: TTVDraw; // Object that renders tree view nodes
fNotifier: INotifier; // Notifies app of user initiated events
fCanChange: Boolean; // Whether selected node allowed to change
Expand DownExpand Up@@ -237,10 +216,6 @@ TTVDraw = class(TSnippetsTVDraw)
procedure RestoreTreeState;
{Restores last saved treeview expansion state from memory.
}
/// <summary>!! HACK: Sets an event handler on the tree view to work
/// around a bug that can occur after resuming from hibernation.</summary>
/// <remarks>Method of IOverviewDisplayMgr.</remarks>
procedure _HACK_SetHibernateHandler(const AHandler: TNotifyEvent);
{ IPaneInfo }
function IsInteractive: Boolean;
{Checks if the pane is currently interactive with user.
Expand DownExpand Up@@ -311,6 +286,7 @@ constructor TOverviewFrame.Create(AOwner: TComponent);
TabIdx: Integer; // loops through tabs
begin
inherited;
fViewStore := TList<IView>.Create;
// Create delegated (contained) command bar manager for toolbar and popup menu
fCommandBars := TCommandBarMgr.Create(Self);
fCommandBars.AddCommandBar(
Expand DownExpand Up@@ -346,6 +322,7 @@ destructor TOverviewFrame.Destroy;
fSelectedItem := nil;
fSnippetList.Free; // does not free referenced snippets
fCommandBars.Free;
fViewStore.Free;
inherited;
end;

Expand DownExpand Up@@ -547,7 +524,7 @@ procedure TOverviewFrame.Redisplay;
Exit;
// Build new treeview using grouping determined by selected tab
Builder := BuilderClasses[tcDisplayStyle.TabIndex].Create(
tvSnippets, fSnippetList
tvSnippets, fSnippetList, fViewStore
);
Builder.Build;
// Restore state of treeview based on last time it was displayed
Expand DownExpand Up@@ -982,12 +959,6 @@ procedure TOverviewFrame.UpdateTreeState(const State: TTreeNodeAction);
end;
end;

procedure TOverviewFrame._HACK_SetHibernateHandler(
const AHandler: TNotifyEvent);
begin
tvSnippets._HACK_OnAfterCreateNilViews := AHandler;
end;

{ TOverviewFrame.TTVDraw }

function TOverviewFrame.TTVDraw.IsSectionHeadNode(
Expand DownExpand Up@@ -1026,24 +997,5 @@ function TOverviewFrame.TTVDraw.IsUserDefinedNode(
Result := False;
end;

{ TTreeView }

procedure TTreeView.CreateWnd;
var
HasNilViews: Boolean;
Node: TTreeNode;
begin
inherited;
HasNilViews := False;
for Node in Items do
begin
HasNilViews := not Assigned((Node as TViewItemTreeNode).ViewItem);
if HasNilViews then
Break;
end;
if HasNilViews and Assigned(_HACK_fOnAfterCreateNilViews) then
_HACK_fOnAfterCreateNilViews(Self);
end;

end.

4 changes: 0 additions & 4 deletions Src/IntfFrameMgrs.pas
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Expand Up@@ -19,7 +19,6 @@ interface
uses
// Delphi
SHDocVw, ActiveX,
Classes, // !! For HACK
// Project
Browser.IntfDocHostUI, DB.USnippet, Compilers.UGlobals, UCommandBars, UView;

Expand DownExpand Up@@ -146,9 +145,6 @@ interface
/// <summary>Restore expand / collapse state of treeview to last save
/// state.</summary>
procedure RestoreTreeState;
/// <summary>!! HACK: Sets an event handler on the tree view to work
/// around a bug that can occur after resuming from hibernation.</summary>
procedure _HACK_SetHibernateHandler(const AHandler: TNotifyEvent);
end;

type
Expand Down
28 changes: 0 additions & 28 deletions Src/UMainDisplayMgr.pas
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Original file line numberDiff line numberDiff line change
Expand Up@@ -165,11 +165,6 @@ TMainDisplayMgr = class(TObject)
procedure DisplayViewItem(ViewItem: IView; Mode: TDetailPageDisplayMode);
overload;

/// <summary>!! HACK event handle to redisplay the overview pane treeview.
/// Called only if Windows has mysteriously recreated the treeview and lost
/// necessary object references.</summary>
procedure _HACK_HibernateHandler(Sender: TObject);

public
/// <summary>Object contructor. Sets up object to work with given frame
/// manager objects.</summary>
Expand DownExpand Up@@ -297,13 +292,6 @@ TMainDisplayMgr = class(TObject)
/// <summary>Prepares display ready for database to be reloaded.</summary>
procedure PrepareForDBReload;

/// <summary>!!HACK: gets the overview frame prepared for program
/// hibernation.</summary>
/// <remarks>Saves the overview tree view state ready for restoring after
/// hibernation if Windows has recreated the overview pane's treeview,
/// losing necessary IView object references..</remarks>
procedure _HACK_PrepareForHibernate;

end;


Expand DownExpand Up@@ -704,21 +692,5 @@ procedure TMainDisplayMgr.UpdateOverviewTreeState(const State: TTreeNodeAction);
(fOverviewMgr as IOverviewDisplayMgr).UpdateTreeState(State);
end;

procedure TMainDisplayMgr._HACK_HibernateHandler(Sender: TObject);
begin
(fOverviewMgr as IOverviewDisplayMgr).Display(Query.Selection, True);
(fOverviewMgr as IOverviewDisplayMgr).RestoreTreeState;
// disable this handler until next resume from hibernation
(fOverviewMgr as IOverviewDisplayMgr)._HACK_SetHibernateHandler(nil);
end;

procedure TMainDisplayMgr._HACK_PrepareForHibernate;
begin
(fOverviewMgr as IOverviewDisplayMgr).SaveTreeState;
(fOverviewMgr as IOverviewDisplayMgr)._HACK_SetHibernateHandler(
_HACK_HibernateHandler
);
end;

end.

21 changes: 17 additions & 4 deletions Src/UOverviewTreeBuilder.pas
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Original file line numberDiff line numberDiff line change
Expand Up@@ -18,6 +18,7 @@ interface

uses
// Delphu
Generics.Collections,
ComCtrls,
// Project
DB.USnippet, UGroups, UView, UViewItemTreeNode;
Expand All@@ -34,11 +35,14 @@ TOverviewTreeBuilder = class abstract(TObject)
var
fTreeView: TTreeView; // Value of TreeView property
fSnippetList: TSnippetList; // Value of SnippetList property
fViewStore : TList<IView>;
strict protected
property TreeView: TTreeView read fTreeView;
{Reference to treeview populated by class}
property SnippetList: TSnippetList read fSnippetList;
{List of snippets to be displayed in treeview}
property ViewStore : TList<IView> read fViewStore;
{List of views attached to treeview nodes}
function AddViewItemNode(const ParentNode: TViewItemTreeNode;
ViewItem: IView): TViewItemTreeNode;
{Adds a new node to the tree view that represents a view item.
Expand All@@ -57,7 +61,7 @@ TOverviewTreeBuilder = class abstract(TObject)
@return Required view item object.
}
public
constructor Create(const TV: TTreeView; const SnippetList: TSnippetList);
constructor Create(const TV: TTreeView; const SnippetList: TSnippetList; const ViewStore : TList<IView>);
{Class constructor. Sets up object to populate a treeview with a list of
snippets.
@param TV [in] Treeview control to be populated.
Expand DownExpand Up@@ -177,7 +181,9 @@ procedure TOverviewTreeBuilder.Build;
ParentNode: TViewItemTreeNode; // each section node in tree
Grouping: TGrouping; // groups snippets
Group: TGroupItem; // each group of snippets
View: IView;
begin
ViewStore.Clear;
// Create required grouping of snippets
Grouping := CreateGrouping;
try
Expand All@@ -186,11 +192,17 @@ procedure TOverviewTreeBuilder.Build;
begin
if not Group.IsEmpty or Preferences.ShowEmptySections then
begin
ParentNode := AddViewItemNode(nil, CreateViewItemForGroup(Group));
View := CreateViewItemForGroup(Group);
ParentNode := AddViewItemNode(nil, View);
ViewStore.Add(View);
for Snippet in Group.SnippetList do
begin
View := TViewFactory.CreateSnippetView(Snippet);
AddViewItemNode(
ParentNode, TViewFactory.CreateSnippetView(Snippet)
ParentNode, View
);
ViewStore.Add(View);
end;
end;
end;
finally
Expand All@@ -199,7 +211,7 @@ procedure TOverviewTreeBuilder.Build;
end;

constructor TOverviewTreeBuilder.Create(const TV: TTreeView;
const SnippetList: TSnippetList);
const SnippetList: TSnippetList; const ViewStore : TList<IView>);
{Class constructor. Sets up object to populate a treeview with a list of
snippets.
@param TV [in] Treeview control to be populated.
Expand All@@ -209,6 +221,7 @@ constructor TOverviewTreeBuilder.Create(const TV: TTreeView;
inherited Create;
fTreeView := TV;
fSnippetList := SnippetList;
fViewStore := ViewStore;
end;

{ TOverviewCategorisedTreeBuilder }
Expand Down
18 changes: 16 additions & 2 deletions Src/UViewItemTreeNode.pas
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Expand Up@@ -31,14 +31,28 @@ interface
}
TViewItemTreeNode = class(TTreeNode)
strict private
var fViewItem: IView; // Value of ViewItem property
function GetViewItem: IView;
procedure SetViewItem(const Value: IView);
published // Value of ViewItem property
public
property ViewItem: IView read fViewItem write fViewItem;
property ViewItem: IView read GetViewItem write SetViewItem;
{View item associated with tree node}
end;


implementation

{ TViewItemTreeNode }

function TViewItemTreeNode.GetViewItem: IView;
begin
Result := IView(Data);
end;

procedure TViewItemTreeNode.SetViewItem(const Value: IView);
begin
Data := Pointer(Value);
end;

end.