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- Generalized TCacheManager (for more type-safety and cleaner code)

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This commit is contained in:
Andreas Schneider
2009-12-08 15:12:09 +01:00
parent c0b5051b00
commit dde886b051
2 changed files with 56 additions and 51 deletions
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51
UCacheManager.pas
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@@ -33,34 +33,39 @@ uses
SysUtils, Classes;
type
TRemoveObjectEvent = procedure(AObject: TObject) of object;
PCacheEntry = ^TCacheEntry;
TCacheEntry = record
ID: Integer;
Obj: TObject;
Next: PCacheEntry;
end;
{ TCacheManager }
TCacheManager = class(TObject)
constructor Create(ASize: Integer);
destructor Destroy; override;
protected
generic TCacheManager<T> = class
type public
{ Types }
TRemoveObjectEvent = procedure(AObject: T) of object;
PCacheEntry = ^TCacheEntry;
TCacheEntry = record
ID: Integer;
Obj: T;
Next: PCacheEntry;
end;
var protected
{ Members }
FSize: Integer;
FFirst: PCacheEntry;
FLast: PCacheEntry;
FOnRemoveObject: TRemoveObjectEvent;
public
constructor Create(ASize: Integer);
destructor Destroy; override;
{ Fields }
property OnRemoveObject: TRemoveObjectEvent read FOnRemoveObject write FOnRemoveObject;
property OnRemoveObject: TRemoveObjectEvent read FOnRemoveObject
write FOnRemoveObject;
{ Methods }
function QueryID(const AID: Integer; out AObj: TObject): Boolean;
procedure StoreID(AID: Integer; AObj: TObject);
function QueryID(const AID: Integer; out AObj: T): Boolean;
procedure StoreID(AID: Integer; AObj: T);
procedure DiscardID(AID: Integer);
procedure DiscardObj(AObj: TObject);
procedure DiscardObj(AObj: T);
procedure RemoveID(AID: Integer);
procedure Clear;
function Iterate(var ACacheEntry: PCacheEntry): Boolean;
@@ -103,7 +108,7 @@ begin
current := FFirst;
for i := 1 to FSize do
begin
if current^.Obj <> nil then
if Pointer(current^.Obj) <> nil then
begin
if Assigned(FOnRemoveObject) then FOnRemoveObject(current^.Obj);
FreeAndNil(current^.Obj);
@@ -132,7 +137,7 @@ begin
end;
end;
procedure TCacheManager.DiscardObj(AObj: TObject);
procedure TCacheManager.DiscardObj(AObj: T);
var
current: PCacheEntry;
begin
@@ -160,7 +165,7 @@ begin
if (current^.ID = AID) then
begin
current^.ID := LongInt($FFFFFFFF);
if current^.Obj <> nil then
if Pointer(current^.Obj) <> nil then
FreeAndNil(current^.Obj);
end;
if (current^.Next <> nil) then
@@ -176,7 +181,7 @@ begin
current := FFirst;
while current <> nil do
begin
if current^.Obj <> nil then
if Pointer(current^.Obj) <> nil then
begin
current^.ID := LongInt($FFFFFFFF);
if Assigned(FOnRemoveObject) then FOnRemoveObject(current^.Obj);
@@ -196,7 +201,7 @@ begin
end;
function TCacheManager.QueryID(const AID: Integer;
out AObj: TObject): Boolean;
out AObj: T): Boolean;
var
current: PCacheEntry;
begin
@@ -222,7 +227,7 @@ begin
end;
end;
procedure TCacheManager.StoreID(AID: Integer; AObj: TObject);
procedure TCacheManager.StoreID(AID: Integer; AObj: T);
var
current: PCacheEntry;
begin
@@ -231,7 +236,7 @@ begin
current^.Next := FFirst;
FFirst := current;
FFirst^.ID := AID;
if FFirst^.Obj <> nil then //if the last cache entry did contain an object, remove it now
if Pointer(FFirst^.Obj) <> nil then //if the last cache entry did contain an object, remove it now
begin
if Assigned(FOnRemoveObject) then FOnRemoveObject(FFirst^.Obj);
FreeAndNil(FFirst^.Obj);