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unit VirtualIconThread;
// Version 1.2.0
// The contents of this file are subject to the Mozilla Public License
// Version 1.1 (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the
// License at
//
// http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an
// " AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either expressed or
// implied. See the License for the specific language governing rights
// and limitations under the License.
//
//
// Alternatively, the contents of this file may be used under
// the terms of the GNU General Public License Version 2 or later
// (the "GPL"), in which case the provisions of the GPL are applicable
// instead of those above. If you wish to allow use of your version of
// this file only under the terms of the GPL and not to allow others to
// use your version of this file under the MPL, indicate your decision
// by deleting the provisions above and replace them with the notice and
// other provisions required by the GPL. If you do not delete the provisions
// above, a recipient may use your version of this file under either the
// MPL or the GPL.
//
// The initial developer of this code is Jim Kueneman <jimdk@mindspring.com>
//
//----------------------------------------------------------------------------
interface
{$include ..\Include\Compilers.inc}
{$include ..\Include\VSToolsAddIns.inc}
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls,
ShlObj, ShellAPI, ActiveX, VirtualShellUtilities, VirtualNamespace,
VirtualResources;
const
SAFETLYVALVEMAX = 20; // Number of times PostMessage it tried if it fails (very unlikely)
type
PVirtualThreadIconInfo = ^TVirtualThreadIconInfo;
TVirtualThreadIconInfo = packed record
PIDL: PItemIDList; // PIDL to the object that requested the image index
IconIndex: integer; // Extracted Icon Index
LargeIcon: Boolean; // Extract the large Icon or Small Icon
Control: TWinControl; // The window that needs the icon
UserData: Pointer; // In VET and VLVEx this is the node. The value in this field is used as the test in ClearPendingItem(TestItem: Pointer) so true is if UserData = TestItem
UserData2: Pointer; // User definable
Tag: integer; // In VLVEx this is the item index
MessageID: LongWord; // The WM_xxx Message to send the control
end;
TWMVTSetIconIndex = packed record
Msg: Cardinal;
IconInfo: PVirtualThreadIconInfo;
end;
type
{ Thread to extract images without slowing down VET }
TVirtualImageThread = class(TThread)
private
FQueryList: TThreadList;
FImageThreadEvent: THandle;
// FMalloc: IMalloc;
FExtractedIconIndex: integer;
protected
procedure AddNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList; LargeIcon: Boolean;
UserData: Pointer; Tag: integer);
procedure ClearPendingItem(Control: TWinControl; TestItem: Pointer;
MessageID: LongWord; const Malloc: IMalloc);
procedure ClearPendingItems(Control: TWinControl; MessageID: LongWord; const Malloc: IMalloc);
function CopyPIDL(APIDL: PItemIDList; const Malloc: IMalloc): PItemIDList;
procedure Execute; override;
function ExtractIconImage(APIDL: PItemIDLIst): Integer;
procedure ExtractInfo(PIDL: PItemIDList; Info: PVirtualThreadIconInfo); virtual;
procedure ExtractedInfoLoad(Info: PVirtualThreadIconInfo); virtual; // Load Info before being sent to Control(s)
procedure InsertNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList;
LargeIcon: Boolean; UserData: Pointer; Tag: integer);
procedure InvalidateExtraction; virtual; // Called if after extraction the item can't be dispatched
function NextID(APIDL: PItemIDList): PItemIDList;
function PIDLSize(APIDL: PItemIDList): Integer;
procedure ReleaseItem(Item: PVirtualThreadIconInfo; const Malloc: IMalloc); virtual;
procedure SetEvent;
function StripLastID(IDList: PItemIDList; var Last_CB: Word; var LastID: PItemIDList): PItemIDList;
property ExtractedIconIndex: integer read FExtractedIconIndex write FExtractedIconIndex;
property ImageThreadEvent: THandle read FImageThreadEvent write FImageThreadEvent;
// property Malloc: IMalloc read FMalloc write FMalloc;
property QueryList: TThreadList read FQueryList;
public
constructor Create(CreateSuspended: Boolean);
destructor Destroy; override;
end;
IVirtualImageThreadManager = interface(IUnknown)
['{F6CDCFE6-4294-4169-A6ED-D1E24F3152AC}']
procedure AddNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList;
LargeIcon: Boolean; UserData: Pointer; Tag: integer);
procedure ClearPendingItems(Control: TWinControl; MessageID: LongWord; const Malloc: IMalloc);
procedure ClearPendingItem(Control: TWinControl; TestItem: Pointer; MessageID: LongWord; const Malloc: IMalloc);
procedure InsertNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList;
LargeIcon: Boolean; UserData: Pointer; Tag: integer);
function LockThread: TList;
procedure RegisterControl(Control: TWinControl);
procedure ReleaseItem(Item: PVirtualThreadIconInfo; const Malloc: IMalloc);
procedure SetThreadPriority(Priority: TThreadPriority);
procedure UnLockThread;
procedure UnRegisterControl(Control: TWinControl);
end;
TVirtualImageThreadManager = class(TInterfacedObject, IVirtualImageThreadManager)
private
FControlList: TThreadList;
FImageThread: TVirtualImageThread;
FThreadPriority: TThreadPriority;
protected
procedure ReleaseImageThread;
function RegisteredControl(Control: TWinControl): Boolean;
property ControlList: TThreadList read FControlList write FControlList;
property ImageThread: TVirtualImageThread read FImageThread write FImageThread;
property ThreadPriority: TThreadPriority read FThreadPriority write FThreadPriority;
public
constructor Create;
destructor Destroy; override;
procedure AddNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList;
LargeIcon: Boolean; UserData: Pointer; Tag: integer);
procedure ClearPendingItems(Control: TWinControl; MessageID: LongWord; const Malloc: IMalloc);
procedure ClearPendingItem(Control: TWinControl; TestItem: Pointer; MessageID: LongWord; const Malloc: IMalloc);
procedure InsertNewItem(Control: TWinControl; WindowsMessageID: LongWord; PIDL: PItemIDList;
LargeIcon: Boolean; UserData: Pointer; Tag: integer);
function LockThread: TList;
procedure RegisterControl(Control: TWinControl);
procedure ReleaseItem(Item: PVirtualThreadIconInfo; const Malloc: IMalloc);
procedure SetThreadPriority(Priority: TThreadPriority);
procedure UnLockThread;
procedure UnRegisterControl(Control: TWinControl);
end;
function ImageThreadManager: IVirtualImageThreadManager;
implementation
var
ImageManager: IVirtualImageThreadManager = nil;
function ImageThreadManager: IVirtualImageThreadManager;
begin
if not Assigned(ImageManager) then
ImageManager := TVirtualImageThreadManager.Create as IVirtualImageThreadManager;
Result := ImageManager
end;
{ TVirtualImageThread }
procedure TVirtualImageThread.AddNewItem(Control: TWinControl; WindowsMessageID: LongWord;
PIDL: PItemIDList; LargeIcon: Boolean; UserData: Pointer; Tag: integer);
var
List: TList;
Info: PVirtualThreadIconInfo;
begin
List := QueryList.LockList;
try
Info := AllocMem(SizeOf(TVirtualThreadIconInfo));
Info.Control := Control;
Info.PIDL := PIDLMgr.CopyPIDL(PIDL);
Info.LargeIcon := LargeIcon;
Info.UserData := UserData;
Info.Tag := Tag;
Info.MessageID := WindowsMessageID;
List.Add(Info);
SetEvent
finally
QueryList.UnlockList;
end
end;
procedure TVirtualImageThread.ClearPendingItem(Control: TWinControl; TestItem: Pointer;
MessageID: Longword; const Malloc: IMalloc);
// This method makes one big assumption. It assumes that the TestItem is equal to the
// PVirtualThreadIconInfo.UserData field.
var
List: TList;
i : integer;
Msg: TMsg;
begin
// Lock the thread from dispatching any more messages
List := QueryList.LockList;
try
// Since we have the list locked we can pick any messages that are in
// message queue that are pending. They may reference the Item we are
// now deleting! By handling this message while the list is locked we
// can be sure all pending icon updates are done before we delete a Item.
if Control.HandleAllocated then
begin
// First flush out any pending messages and let them be processed
while PeekMessage(Msg, Control.Handle, MessageID, MessageID, PM_REMOVE) do
begin
TranslateMessage(Msg);
DispatchMessage(Msg)
end;
end;
for i := 0 to List.Count - 1 do
begin
if (PVirtualThreadIconInfo(List[i])^.Control = Control) then
begin
if (TestItem = PVirtualThreadIconInfo(List[i])^.UserData) then
begin
ReleaseItem(PVirtualThreadIconInfo(List[i]), Malloc);
List[i] := nil
end
end
end;
List.Pack;
finally
QueryList.UnlockList;
end
end;
procedure TVirtualImageThread.ClearPendingItems(Control: TWinControl; MessageID: LongWord; const Malloc: IMalloc);
var
List: TList;
i : integer;
Msg: TMsg;
begin
// Lock the thread from dispatching any more messages
List := QueryList.LockList;
try
// Since we have the list locked we can pick any messages that are in
// message queue that are pending. They may reference the Item we are
// now deleting! By handling this message while the list is locked we
// can be sure all pending icon updates are done before we delete a Item.
if Control.HandleAllocated then
begin
// First flush out any pending messages and let them be processed
while PeekMessage(Msg, Control.Handle, MessageID, MessageID, PM_REMOVE) do
begin
TranslateMessage(Msg);
DispatchMessage(Msg)
end;
end;
for i := 0 to List.Count - 1 do
begin
if (PVirtualThreadIconInfo(List[i])^.Control = Control) then
begin
ReleaseItem(PVirtualThreadIconInfo(List[i]), Malloc);
List[i] := nil
end
end;
List.Pack;
finally
QueryList.UnlockList;
end
end;
function TVirtualImageThread.CopyPIDL(APIDL: PItemIDList; const Malloc: IMalloc): PItemIDList;
// Copies the PIDL and returns a newly allocated PIDL. It is not associated
// with any instance of TPIDLManager so it may be assigned to any instance.
var
Size: integer;
begin
if Assigned(APIDL) then
begin
Size := PIDLSize(APIDL);
Result := Malloc.Alloc(Size);
if Result <> nil then
CopyMemory(Result, APIDL, Size);
end else
Result := nil
end;
constructor TVirtualImageThread.Create(CreateSuspended: Boolean);
begin
inherited Create(CreateSuspended);
{ NEED A UNIQUE EVENT FOR EACH THREAD IDIOT!!!}
ImageThreadEvent := CreateEvent(nil, True, False, '');
FQueryList := TThreadList.Create;
end;
destructor TVirtualImageThread.Destroy;
begin
inherited;
{ Important to keep resources valid until after the inherited Destroy returns. }
{ The Execute method is terminated during a WaitFor called in this destructor. }
{ During that time Execute may still reference these resources. }
FQueryList.Free;
if ImageThreadEvent <> 0 then
CloseHandle(ImageThreadEvent);
end;
procedure TVirtualImageThread.Execute;
var
Index: Integer;
List: TList;
SafetyValve: integer;
Info: PVirtualThreadIconInfo;
PIDL: PItemIDList;
Malloc: IMalloc;
begin
CoInitialize(nil);
try
SHGetMalloc(Malloc); // Create in the context of the thread
while not Terminated do
begin
WaitForSingleObject(ImageThreadEvent, INFINITE);
if not Terminated then
begin
// Ok everyone .... breath
Sleep(1);
// Get the next waiting node
List := QueryList.LockList;
try
Info := nil;
// Grab the last item but don't remove it from the list yet.
// If we remove it then if a control flushs pending queries before
// we dispatch it we will send it to a control that is not ready.
// If there are not items in the list then we are done so reset
// local varaibles and reset the event so WaitForSingleObject waits again
if List.Count > 0 then
begin
Index := List.Count - 1;
Info := PVirtualThreadIconInfo(List.Items[Index]);
// We can't use the actual Info object as it my be deleted on us
PIDL := CopyPIDL(Info.PIDL, Malloc);
end
else begin
Index := -1;
PIDL := nil;
ResetEvent(ImageThreadEvent); // Reset ourselves when there are no more images
end;
finally
QueryList.UnlockList
end;
// Check again to see if we are terminated
if Assigned(PIDL) then
try
// Call the long processing method if necessary.
ExtractInfo(PIDL, Info);
// Ok the slow extraction is done time to dispatch it
List := QueryList.LockList;
try
// Free the temp PIDL
if PIDL <> nil then
Malloc.Free(PIDL);
// Check to see if there are any items in the list or if items have
// been deleted first. If they are the item will be left if the queue
// and it will have to be done again
if (List.Count > 0) and (Index < List.Count) then
begin
// See if the node was deleted and removed from the list or the
// contexts were shifted
if List[Index] = Info then
begin
ExtractedInfoLoad(Info);
// No it is still there so we can remove it
List.Delete(Index);
// Note: It is possible by the time the VET gets this TMessage
// the node can be destroyed so main thread locks the list
// the PeekMessage's to remove all WM_VTSETICONINDEX before
// freeing node.
// Can't SendMessage because the main thread may be blocked
// waiting for the list and SendMessage will deadlock.
// Here again accessing a TWinControl is not thread safe but
// we are only reading the properties
if Info.Control.HandleAllocated then
begin
SafetyValve := 0;
while not PostMessage(Info.Control.Handle, Info.MessageID, Integer(Info), 0) and (SafetyValve < SAFETLYVALVEMAX) do
begin
Inc(SafetyValve);
Sleep(1);
end;
if SafetyValve >= SAFETLYVALVEMAX then
ReleaseItem(Info, Malloc)
end else
ReleaseItem(Info, Malloc)
end else
InvalidateExtraction
end else
InvalidateExtraction
finally
QueryList.UnlockList;
end
except
// Don't let exceptions escape the thread
end
end
end
finally
// Make sure WaitFor is in the Wait Function before the thread really ends
Sleep(100);
Malloc := nil;
CoUninitialize;
end;
end;
procedure TVirtualImageThread.ExtractedInfoLoad(Info: PVirtualThreadIconInfo);
// This is called from within a locked list so it is safe to maniulate
begin
Info.IconIndex := ExtractedIconIndex;
end;
function TVirtualImageThread.ExtractIconImage(APIDL: PItemIDLIst): integer;
function GetIconByIShellIcon(PIDL: PItemIDList; var Index: integer): Boolean;
var
Flags: Longword;
OldCB: Word;
Old_ID: PItemIDList;
{$IFNDEF VIRTUALNAMESPACES}
Desktop,
{$ENDIF}
Folder: IShellFolder;
ShellIcon: IShellIcon;
begin
Result := False;
StripLastID(PIDL, OldCB, Old_ID);
try
{$IFDEF VIRTUALNAMESPACES}
Old_ID.mkid.cb := OldCB;
Folder := NamespaceExtensionFactory.BindToVirtualParentObject(PIDL);
{$ELSE}
SHGetDesktopFolder(Desktop);
Desktop.BindToObject(PIDL, nil, IShellFolder, Pointer(Folder));
Old_ID.mkid.cb := OldCB;
{$ENDIF}
if Assigned(Folder) then
if Folder.QueryInterface(IShellIcon, ShellIcon) = S_OK then
begin
Flags := 0;
Result := ShellIcon.GetIconOf(Old_ID, Flags, Index) = NOERROR
end
finally
{$IFNDEF VIRTUALNAMESPACES}
Old_ID.mkid.cb := OldCB
{$ENDIF}
end
end;
procedure GetIconBySHGetFileInfo(APIDL: PItemIDList; var Index: Integer);
var
Flags: integer;
Info: TSHFILEINFO;
begin
Flags := SHGFI_PIDL or SHGFI_SYSICONINDEX or SHGFI_SHELLICONSIZE;
Flags := Flags or SHGFI_SMALLICON;
if SHGetFileInfo(PChar(APIDL), 0, Info, SizeOf(Info), Flags) <> 0 then
Index := Info.iIcon
else
Index := 0
end;
begin
if not GetIconByIShellIcon(APIDL, Result) then
GetIconBySHGetFileInfo(APIDL, Result);
end;
procedure TVirtualImageThread.ExtractInfo(PIDL: PItemIDList; Info: PVirtualThreadIconInfo);
// Use the passed PIDL to figure out what what to extract
begin
ExtractedIconIndex := ExtractIconImage(PIDL);
end;
procedure TVirtualImageThread.InsertNewItem(Control: TWinControl;
WindowsMessageID: LongWord; PIDL: PItemIDList; LargeIcon: Boolean;
UserData: Pointer; Tag: integer);
var
List: TList;
Info: PVirtualThreadIconInfo;
begin
List := QueryList.LockList;
try
Info := AllocMem(SizeOf(TVirtualThreadIconInfo));
Info.Control := Control;
Info.PIDL := PIDLMgr.CopyPIDL(PIDL);
Info.LargeIcon := LargeIcon;
Info.UserData := UserData;
Info.Tag := Tag;
Info.MessageID := WindowsMessageID;
List.Insert(0, Info);
SetEvent
finally
QueryList.UnlockList;
end
end;
procedure TVirtualImageThread.InvalidateExtraction;
begin
end;
function TVirtualImageThread.NextID(APIDL: PItemIDList): PItemIDList;
begin
Result := APIDL;
if Assigned(APIDL) then
Inc(PChar(Result), APIDL^.mkid.cb);
end;
function TVirtualImageThread.PIDLSize(APIDL: PItemIDList): integer;
// Returns the total Memory in bytes the PIDL occupies.
begin
Result := 0;
if Assigned(APIDL) then
begin
Result := SizeOf( Word); // add the null terminating last ItemID
while APIDL.mkid.cb <> 0 do
begin
Result := Result + APIDL.mkid.cb;
APIDL := NextID(APIDL);
end;
end;
end;
procedure TVirtualImageThread.ReleaseItem(Item: PVirtualThreadIconInfo; const Malloc: IMalloc);
begin
if Assigned(Item) then
begin
if Assigned(Item.PIDL) then
Malloc.Free(Item.PIDL);
FreeMem(Item)
end
end;
procedure TVirtualImageThread.SetEvent;
begin
Windows.SetEvent(ImageThreadEvent);
end;
function TVirtualImageThread.StripLastID(IDList: PItemIDList;
var Last_CB: Word; var LastID: PItemIDList): PItemIDList;
var
MarkerID: PItemIDList;
begin
Last_CB := 0;
LastID := nil;
Result := IDList;
MarkerID := IDList;
if Assigned(IDList) then
begin
while IDList.mkid.cb <> 0 do
begin
MarkerID := IDList;
IDList := NextID(IDList);
end;
Last_CB := MarkerID.mkid.cb;
LastID := MarkerID;
MarkerID.mkid.cb := 0;
end;
end;
{ TVirtualImageThreadManager }
procedure TVirtualImageThreadManager.AddNewItem(Control: TWinControl; WindowsMessageID: LongWord;
PIDL: PItemIDList; LargeIcon: Boolean; UserData: Pointer; Tag: integer);
begin
if Assigned(ImageThread) then
begin
Assert(RegisteredControl(Control), 'Trying to add Image Thread Item to a unregistered control');
ImageThread.AddNewItem(Control, WindowsMessageID, PIDL, LargeIcon, UserData, Tag)
end
end;
procedure TVirtualImageThreadManager.ClearPendingItem(Control: TWinControl;
TestItem: Pointer; MessageID: LongWord; const Malloc: IMalloc);
// Looks for the matching TestItem in the Item field of the record as a flag to delete
// the record
begin
if Assigned(ImageThread) then
begin
if RegisteredControl(Control) then
begin
ImageThread.ClearPendingItem(Control, TestItem, MessageID, Malloc)
end else
Assert(True=False, 'Trying to clear pending Image Thead Items from an unregistered control');
end
end;
procedure TVirtualImageThreadManager.ClearPendingItems(Control: TWinControl; MessageID: LongWord; const Malloc: IMalloc);
begin
if Assigned(ImageThread) then
begin
if RegisteredControl(Control) then
begin
ImageThread.ClearPendingItems(Control, MessageID, Malloc)
end else
Assert(True=False, 'Trying to clear pending Image Thead Items from an unregistered control');
end
end;
constructor TVirtualImageThreadManager.Create;
begin
ControlList := TThreadList.Create;
ThreadPriority := tpNormal;
end;
destructor TVirtualImageThreadManager.Destroy;
begin
ReleaseImageThread;
ControlList.Free;
inherited;
end;
function TVirtualImageThreadManager.LockThread: TList;
begin
if Assigned(ImageThread) then
Result := ImageThread.QueryList.LockList
else
Result := nil
end;
procedure TVirtualImageThreadManager.InsertNewItem(Control: TWinControl;
WindowsMessageID: LongWord; PIDL: PItemIDList; LargeIcon: Boolean;
UserData: Pointer; Tag: integer);
begin
if Assigned(ImageThread) then
begin
Assert(RegisteredControl(Control), 'Trying to add Image Thread Item to a unregistered control');
ImageThread.InsertNewItem(Control, WindowsMessageID, PIDL, LargeIcon, UserData, Tag)
end
end;
procedure TVirtualImageThreadManager.RegisterControl(Control: TWinControl);
var
List: TList;
begin
List := ControlList.LockList;
try
List.Add(Control);
if not Assigned(ImageThread) then
begin
ImageThread := TVirtualImageThread.Create(False);
ImageThread.Priority := ThreadPriority;
end
finally
ControlList.UnlockList
end
end;
function TVirtualImageThreadManager.RegisteredControl( Control: TWinControl): Boolean;
var
List: TList;
begin
if Assigned(Control) then
begin
List := ControlList.LockList;
try
Result := List.IndexOf(Control) > -1
finally
ControlList.UnlockList
end
end else
Result := False;
end;
procedure TVirtualImageThreadManager.ReleaseItem(Item: PVirtualThreadIconInfo; const Malloc: IMalloc);
begin
ImageThread.ReleaseItem(Item, Malloc)
end;
procedure TVirtualImageThreadManager.ReleaseImageThread;
begin
if Assigned(ImageThread) then
begin
ImageThread.Priority := tpNormal; // So D6 shuts down faster.
ImageThread.Terminate;
ImageThread.SetEvent;
ImageThread.WaitFor;
FreeAndNil(FImageThread)
end
end;
procedure TVirtualImageThreadManager.SetThreadPriority(
Priority: TThreadPriority);
begin
ThreadPriority := Priority;
if Assigned(ImageThread) then
ImageThread.Priority := ThreadPriority
end;
procedure TVirtualImageThreadManager.UnLockThread;
begin
if Assigned(ImageThread) then
ImageThread.QueryList.UnLockList
end;
procedure TVirtualImageThreadManager.UnRegisterControl(Control: TWinControl);
var
List: TList;
Index: integer;
begin
List := ControlList.LockList;
try
Index := List.IndexOf(Control);
if Index > -1 then
begin
List.Delete(Index);
if List.Count = 0 then
ReleaseImageThread;
end
finally
ControlList.UnlockList
end
end;
initialization
finalization
ImageManager := nil;
end.
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