udr/client/FBTransaction.pas

(*
 *  Firebird Interface (fbintf). The fbintf components provide a set of
 *  Pascal language bindings for the Firebird API. Although predominantly
 *  a new development they include source code taken from IBX and may be
 *  considered a derived product. This software thus also includes the copyright
 *  notice and license conditions from IBX.
 *
 *  Except for those parts dervied from IBX, contents of this file are subject
 *  to the Initial Developer's Public License Version 1.0 (the "License"); you
 *  may not use this file except in compliance with the License. You may obtain a
 *  copy of the License here:
 *
 *    http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Initial Developer of the Original Code is Tony Whyman.
 *
 *  The Original Code is (C) 2016 Tony Whyman, MWA Software
 *  (http://www.mwasoftware.co.uk).
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): ______________________________________.
 *
*)
{************************************************************************}
{                                                                        }
{       Borland Delphi Visual Component Library                          }
{       InterBase Express core components                                }
{                                                                        }
{       Copyright (c) 1998-2000 Inprise Corporation                      }
{                                                                        }
{    InterBase Express is based in part on the product                   }
{    Free IB Components, written by Gregory H. Deatz for                 }
{    Hoagland, Longo, Moran, Dunst & Doukas Company.                     }
{    Free IB Components is used under license.                           }
{                                                                        }
{    The contents of this file are subject to the InterBase              }
{    Public License Version 1.0 (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.Inprise.com/IPL.html }
{    Software distributed under the License is distributed on            }
{    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either              }
{    express or implied. See the License for the specific language       }
{    governing rights and limitations under the License.                 }
{    The Original Code was created by InterBase Software Corporation     }
{       and its successors.                                              }
{    Portions created by Inprise Corporation are Copyright (C) Inprise   }
{       Corporation. All Rights Reserved.                                }
{    Contributor(s): Jeff Overcash                                       }
{                                                                        }
{    IBX For Lazarus (Firebird Express)                                  }
{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
{    Portions created by MWA Software are copyright McCallum Whyman      }
{    Associates Ltd 2011 - 2015                                                }
{                                                                        }
{************************************************************************}
unit FBTransaction;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$interfaces COM}
{$ENDIF}

interface

uses
  Classes, SysUtils, IB, FBParamBlock, FBActivityMonitor, FBClientAPI, FBOutputBlock;

type
  { TFBTransaction }

  TFBTransaction = class(TActivityReporter, IActivityMonitor,ITransaction)
  private
    FFirebirdAPI: TFBClientAPI;
    function GenerateTPB(sl: array of byte): ITPB;
  protected
    FTPB: ITPB;
    FSeqNo: integer;
    FDefaultCompletion: TTransactionCompletion;
    FAttachments: array of IAttachment; {Keep reference to attachment - ensures
                                          attachment cannot be freed before transaction}
    FTransactionName: AnsiString;
    FForeignHandle: boolean;
    procedure CheckHandle;
    function GetActivityIntf(att: IAttachment): IActivityMonitor; virtual; abstract;
    function GetJournalIntf(Attachment: IAttachment): IJournallingHook;
    procedure SetInterface(api: TFBClientAPI); virtual;
    function GetTrInfo(ReqBuffer: PByte; ReqBufLen: integer): ITrInformation; virtual; abstract;
    procedure InternalStartSingle(attachment: IAttachment); virtual; abstract;
    procedure InternalStartMultiple; virtual; abstract;
    procedure InternalCommit(Force: boolean); virtual; abstract;
    procedure InternalCommitRetaining; virtual; abstract;
    procedure InternalRollback(Force: boolean); virtual; abstract;
    procedure InternalRollbackRetaining; virtual; abstract;
  public
    constructor Create(api: TFBClientAPI; Attachments: array of IAttachment; Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
    constructor Create(api: TFBClientAPI; Attachments: array of IAttachment; TPB: ITPB; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
    constructor Create(api: TFBClientAPI; Attachment: IAttachment; Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
    constructor Create(api: TFBClientAPI; Attachment: IAttachment; TPB: ITPB; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
    destructor Destroy; override;
    procedure DoDefaultTransactionEnd(Force: boolean);
    property FirebirdAPI: TFBClientAPI read FFirebirdAPI;

  public
    {ITransaction}
    function getTPB: ITPB;
    procedure PrepareForCommit;virtual; abstract;
    procedure Commit(Force: boolean=false);
    procedure CommitRetaining;
    function GetInTransaction: boolean; virtual; abstract;
    function GetIsReadOnly: boolean;
    function GetTransactionID: integer;
    function GetAttachmentCount: integer;
    function GetAttachment(index: integer): IAttachment;
    function GetJournalingActive(attachment: IAttachment): boolean;
    function GetDefaultCompletion: TTransactionCompletion;
    procedure Rollback(Force: boolean=false);
    procedure RollbackRetaining;
    procedure Start(DefaultCompletion: TTransactionCompletion=taCommit); overload;
    procedure Start(TPB: ITPB; DefaultCompletion: TTransactionCompletion=taCommit); overload;
    function GetTrInformation(Requests: array of byte): ITrInformation; overload;
    function GetTrInformation(Request: byte): ITrInformation; overload;
    function GetTransactionName: AnsiString;
    procedure SetTransactionName(aValue: AnsiString);

    property InTransaction: boolean read GetInTransaction;
    property TransactionSeqNo: integer read FSeqNo;
  end;

  {The transaction user interface is used to force an action on the end of the
   transaction.}

  ITransactionUser = interface
    ['{156fcdc9-a326-44b3-a82d-f23c6fb9f97c}']
    procedure TransactionEnding(aTransaction: ITransaction; Force: boolean);
  end;

  { TTPBItem }

  TTPBItem = class(TParamBlockItem,ITPBItem)
  public
    function getParamTypeName: AnsiString; override;
  end;

  { TTPB }

  TTPB = class (TCustomParamBlock<TTPBItem,ITPBItem>, ITPB)
  protected
    function LookupItemType(ParamTypeName: AnsiString): byte; override;
  public
    constructor Create(api: TFBClientAPI);
    function GetParamTypeName(ParamType: byte): Ansistring;
    {$IFDEF FPC}
    function ITPB.GetDPBParamTypeName = GetParamTypeName;
    {$ELSE}
    function GetDPBParamTypeName(ParamType: byte): Ansistring;
    {$ENDIF}
    function AsText: AnsiString;
end;

  {$IFDEF FPC}
  TTrInfoItem = class;

  { TTrInfoItem }

  TTrInfoItem = class(TOutputBlockItemGroup<TTrInfoItem,ITrInfoItem>,ITrInfoItem)
  {$ELSE}
    TTrInfoItem = class(TOutputBlockItemGroup<TOutputBlockItem,ITrInfoItem>,ITrInfoItem)
  {$ENDIF}
    public
      procedure DecodeTraIsolation(var IsolationType, RecVersion: byte);
  end;

  { TTrInformation }

  TTrInformation = class(TCustomOutputBlock<TTrInfoItem,ITrInfoItem>, ITrInformation)
  protected
    procedure DoParseBuffer; override;
  public
    constructor Create(api: TFBClientAPI; aSize: integer = DefaultBufferSize);
    {$IFNDEF FPC}
    function Find(ItemType: byte): ITrInfoItem;
    {$ENDIF}
  end;


implementation

uses FBMessages;

const
  isc_tpb_last_tpb_constant = isc_tpb_at_snapshot_number;

  TPBConstantNames: array[1..isc_tpb_last_tpb_constant] of string = (
    'consistency',
    'concurrency',
    'shared',
    'protected',
    'exclusive',
    'wait',
    'nowait',
    'read',
    'write',
    'lock_read',
    'lock_write',
    'verb_time',
    'commit_time',
    'ignore_limbo',
    'read_committed',
    'autocommit',
    'rec_version',
    'no_rec_version',
    'restart_requests',
    'no_auto_undo',
    'lock_timeout',
    'read_consistency',
    'at_snapshot_number'
  );

{ TFBTransaction }

function TFBTransaction.GenerateTPB(sl: array of byte): ITPB;
var
  i: Integer;
begin
  Result := TTPB.Create(FFirebirdAPI);
  for i := 0 to Length(sl) - 1 do
    Result.Add(sl[i]);
end;

procedure TFBTransaction.CheckHandle;
begin
  if not InTransaction then
    IBError(ibxeNotInTransaction,[]);
end;

function TFBTransaction.GetJournalIntf(Attachment: IAttachment): IJournallingHook;
begin
  Attachment.QueryInterface(IJournallingHook,Result)
end;

procedure TFBTransaction.SetInterface(api: TFBClientAPI);
begin
  FFirebirdAPI := api;
end;

constructor TFBTransaction.Create(api: TFBClientAPI; Attachments: array of IAttachment;
  Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString);
begin
  Create(api, Attachments,GenerateTPB(Params), DefaultCompletion, aName);
end;

constructor TFBTransaction.Create(api: TFBClientAPI; Attachments: array of IAttachment; TPB: ITPB;
  DefaultCompletion: TTransactionAction; aName: AnsiString);
var
  i: Integer;
begin
  inherited Create(nil);
  FTransactionName := aName;
  SetInterface(api);
  if Length(Attachments) = 0 then
    IBError(ibxeEmptyAttachmentsList,[nil]);

  {make sure all attachments use same Firebird API}
  for i := 0 to Length(Attachments) - 1 do
    if Attachments[i].getFirebirdAPI.GetFBLibrary.GetHandle <> FFirebirdAPI.GetFBLibrary.GetHandle then
      IBError(ibxeDifferentAPIs,[nil]);

  SetLength(FAttachments,Length(Attachments));
  for i := 0 to Length(Attachments) - 1 do
  begin
    AddMonitor(GetActivityIntf(Attachments[i]));
    FAttachments[i] := Attachments[i];
  end;
  FTPB := TPB;
  Start(DefaultCompletion);
end;

constructor TFBTransaction.Create(api: TFBClientAPI; Attachment: IAttachment;
  Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString);
begin
  Create(api,Attachment,GenerateTPB(Params),DefaultCompletion,aName);
end;

constructor TFBTransaction.Create(api: TFBClientAPI; Attachment: IAttachment; TPB: ITPB;
  DefaultCompletion: TTransactionAction; aName: AnsiString);
begin
  inherited Create(nil);
  SetInterface(api);
  AddMonitor(GetActivityIntf(Attachment));
  SetLength(FAttachments,1);
  FAttachments[0] := Attachment;
  FTPB := TPB;
  FTransactionName := aName;
  Start(DefaultCompletion);
end;

destructor TFBTransaction.Destroy;
begin
  DoDefaultTransactionEnd(false);
  inherited Destroy;
end;

procedure TFBTransaction.DoDefaultTransactionEnd(Force: boolean);
var i: integer;
    intf: IUnknown;
    user: ITransactionUser;
begin
  if InTransaction and not FForeignHandle then
  begin
    for i := 0 to InterfaceCount - 1 do
    begin
      intf := GetInterface(i);
      if (intf <> nil) and  (intf.QueryInterface(ITransactionUser,user) = S_OK) then
        user.TransactionEnding(self,Force);
    end;
    case FDefaultCompletion of
    taRollback:
      Rollback(Force);
    taCommit:
      Commit(Force);
    end;
  end;
end;

function TFBTransaction.getTPB: ITPB;
begin
  Result := FTPB;
end;

procedure TFBTransaction.Commit(Force: boolean);
var i: integer;
    TransactionID: integer;
    TransactionEndNeeded: array of boolean;
begin
  if not GetInTransaction then Exit;

  if FForeignHandle then
    IBError(ibxeTransactionNotOwned,[nil]);

  SetLength(TransactionEndNeeded,Length(FAttachments));
  TransactionID := GetTransactionID;
  for i := 0 to Length(FAttachments) - 1 do
    if (FAttachments[i] <> nil)  then
      TransactionEndNeeded[i] := GetJournalingActive(FAttachments[i])
    else
      TransactionEndNeeded[i] := false;
  InternalCommit(Force);
  for i := 0 to Length(FAttachments) - 1 do
    if TransactionEndNeeded[i] then
       GetJournalIntf(FAttachments[i]).TransactionEnd(TransactionID, TACommit);
end;

procedure TFBTransaction.CommitRetaining;
var i: integer;
    TransactionID: integer;
begin
  if not GetInTransaction then Exit;

  TransactionID := GetTransactionID;
  InternalCommitRetaining;
  for i := 0 to Length(FAttachments) - 1 do
    if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
       GetJournalIntf(FAttachments[i]).TransactionRetained(self,TransactionID, TACommitRetaining);
end;

function TFBTransaction.GetIsReadOnly: boolean;
var Info: ITrInformation;
begin
  Info := GetTrInformation(isc_info_tra_access);
  if (Info.Count > 0) and (Info[0].getItemType = isc_info_tra_access) then
    Result := Info[0].getAsInteger = isc_info_tra_readonly
  else
    Result := false;
end;

function TFBTransaction.GetTransactionID: integer;
var Info: ITrInformation;
begin
  Result := -1;
  Info := GetTrInformation(isc_info_tra_id);
  if (Info.Count > 0) and (Info[0].getItemType = isc_info_tra_id) then
    Result := Info[0].getAsInteger;
end;

function TFBTransaction.GetAttachmentCount: integer;
begin
  Result := Length(FAttachments);
end;

function TFBTransaction.GetAttachment(index: integer): IAttachment;
begin
  if (index >= 0) and (index < Length(FAttachments)) then
    Result := FAttachments[index]
  else
    IBError(ibxeAttachmentListIndexError,[index]);
end;

function TFBTransaction.GetJournalingActive(attachment: IAttachment): boolean;
begin
  Result := false;
  if (attachment = nil) and (length(FAttachments) > 0) then
    attachment := FAttachments[0];
  if attachment <> nil then
  with attachment do
  Result := self.GetInTransaction and JournalingActive and
     ((((joReadOnlyTransactions in GetJournalOptions) and self.GetIsReadOnly)) or
     ((joReadWriteTransactions in GetJournalOptions) and not self.GetIsReadOnly));
end;

function TFBTransaction.GetDefaultCompletion: TTransactionCompletion;
begin
  Result := FDefaultCompletion;
end;

procedure TFBTransaction.Rollback(Force: boolean);
var i: integer;
    TransactionID: integer;
    TransactionEndNeeded: array of boolean;
begin
  if not GetInTransaction then Exit;

  if FForeignHandle then
    IBError(ibxeTransactionNotOwned,[nil]);

  SetLength(TransactionEndNeeded,Length(FAttachments));
  TransactionID := GetTransactionID;
  for i := 0 to Length(FAttachments) - 1 do
    if (FAttachments[i] <> nil)  then
      TransactionEndNeeded[i] := GetJournalingActive(FAttachments[i])
    else
      TransactionEndNeeded[i] := false;
  InternalRollback(Force);
  for i := 0 to Length(FAttachments) - 1 do
    if TransactionEndNeeded[i] then
       GetJournalIntf(FAttachments[i]).TransactionEnd(TransactionID, TARollback);
end;

procedure TFBTransaction.RollbackRetaining;
var i: integer;
    TransactionID: integer;
begin
  if not GetInTransaction then Exit;

  TransactionID := GetTransactionID;
  InternalRollbackRetaining;
  for i := 0 to Length(FAttachments) - 1 do
    if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
       GetJournalIntf(FAttachments[i]).TransactionRetained(self,TransactionID,TARollbackRetaining);
end;

procedure TFBTransaction.Start(DefaultCompletion: TTransactionCompletion);
var i: integer;
begin
  if GetInTransaction then
    Exit;

  FDefaultCompletion := DefaultCompletion;

  if Length(FAttachments) = 1 then
    InternalStartSingle(FAttachments[0])
  else
    InternalStartMultiple;
  for i := 0 to Length(FAttachments) - 1 do
    if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
      GetJournalIntf(FAttachments[i]).TransactionStart(self);
  Inc(FSeqNo);
end;

procedure TFBTransaction.Start(TPB: ITPB; DefaultCompletion: TTransactionCompletion
  );
begin
  FTPB := TPB;
  Start(DefaultCompletion);
end;

function TFBTransaction.GetTrInformation(Requests: array of byte
  ): ITrInformation;
var ReqBuffer: PByte;
    i: integer;
begin
  CheckHandle;
  if Length(Requests) = 1 then
    Result := GetTrInformation(Requests[0])
  else
  begin
    GetMem(ReqBuffer,Length(Requests));
    try
      for i := 0 to Length(Requests) - 1 do
        ReqBuffer[i] := Requests[i];

      Result := GetTrInfo(ReqBuffer,Length(Requests));

    finally
      FreeMem(ReqBuffer);
    end;
  end;
end;

function TFBTransaction.GetTrInformation(Request: byte): ITrInformation;
begin
  CheckHandle;
  Result := GetTrInfo(@Request,1);
end;

function TFBTransaction.GetTransactionName: AnsiString;
begin
  Result := FTransactionName;
end;

procedure TFBTransaction.SetTransactionName(aValue: AnsiString);
begin
  FTransactionName := aValue;
end;

{ TTPBItem }

function TTPBItem.getParamTypeName: AnsiString;
begin
  Result :=  TPBPrefix + TPBConstantNames[getParamType];
end;


{TTPB}

constructor TTPB.Create(api: TFBClientAPI);
begin
  inherited Create(api);
  FDataLength := 1;
  FBuffer^ := isc_tpb_version3;
end;

function TTPB.GetParamTypeName(ParamType: byte): Ansistring;
begin
  if ParamType <= isc_tpb_last_tpb_constant then
    Result := TPBPrefix + TPBConstantNames[ParamType]
  else
    Result := '';
end;

function TTPB.AsText: AnsiString;
var i: integer;
begin
  Result := '[';
  for i := 0 to getCount - 1 do
  begin
    Result := Result + GetParamTypeName(getItems(i).getParamType);
    if i < getCount - 1 then
      Result := Result + ',';
  end;
  Result := Result + ']';
end;

{$IFNDEF FPC}
function TTPB.GetDPBParamTypeName(ParamType: byte): Ansistring;
begin
  Result := GetParamTypeName(ParamType);
end;
{$ENDIF}


function TTPB.LookupItemType(ParamTypeName: AnsiString): byte;
var i: byte;
begin
  Result := 0;
  ParamTypeName := LowerCase(ParamTypeName);
  if (Pos(TPBPrefix, ParamTypeName) = 1) then
    Delete(ParamTypeName, 1, Length(TPBPrefix));

  for i := 1 to isc_tpb_last_tpb_constant do
    if (ParamTypeName = TPBConstantNames[i]) then
    begin
      Result := i;
      break;
    end;
end;

{ TTrInfoItem }

procedure TTrInfoItem.DecodeTraIsolation(var IsolationType, RecVersion: byte);
begin
  with FFirebirdClientAPI, ItemData^ do
  if getItemType = isc_info_tra_isolation then
  begin
    if FDataLength = 1 then
    begin
      IsolationType := getAsInteger;
      RecVersion := 0;
    end
    else
    begin
      IsolationType := (FBufPtr + 3)^;
      RecVersion := (FBufPtr + 4)^;
    end
  end
  else
    IBError(ibxeInfoBufferTypeError,[integer(FBufPtr^)]);
end;

{ TTrInformation }

procedure TTrInformation.DoParseBuffer;
var P: PByte;
    index: integer;
begin
  P := Buffer;
  index := 0;
  SetLength(FItems,0);
  while (P^ <> isc_info_end) and (P < Buffer + getBufSize) do
  begin
    SetLength(FItems,index+1);
    case byte(P^) of
    isc_info_tra_id,
    isc_info_tra_oldest_interesting,
    isc_info_tra_oldest_active,
    isc_info_tra_oldest_snapshot,
    fb_info_tra_snapshot_number,
    isc_info_tra_lock_timeout:
      FItems[index] := AddIntegerItem(P);

    isc_info_tra_isolation,
      {return transaction isolation mode of current transaction.
        format of returned clumplets is following:

        isc_info_tra_isolation,
                1, isc_info_tra_consistency | isc_info_tra_concurrency
        |
                2, isc_info_tra_read_committed,
                         isc_info_tra_no_rec_version | isc_info_tra_rec_version

        i.e. for read committed transactions returned 2 items while for
        other transactions returned 1 item}

    isc_info_tra_access:
      FItems[index] := AddIntegerItem(P);
    fb_info_tra_dbpath:
      FItems[index] := AddStringItem(P);
    else
      FItems[index] := AddItem(P);
    end;
    P := P + FItems[index]^.FSize;
    Inc(index);
  end;
end;

constructor TTrInformation.Create(api: TFBClientAPI; aSize: integer);
begin
  inherited Create(api,aSize);
  FIntegerType := dtInteger;
end;

{$IFNDEF FPC}
function TTrInformation.Find(ItemType: byte): ITrInfoItem;
begin
  Result := inherited Find(ItemType);
  if Result.GetSize = 0 then
    Result := nil;
end;
{$ENDIF}

end.

Revision:	371
Committed:	Wed Jan 5 15:21:22 2022 UTC (2 years, 3 months ago) by tony
Content type:	text/x-pascal
File size:	20676 byte(s)
Log Message:	Beta Release 0.1
#	Content
1	(*
2	* Firebird Interface (fbintf). The fbintf components provide a set of
3	* Pascal language bindings for the Firebird API. Although predominantly
4	* a new development they include source code taken from IBX and may be
5	* considered a derived product. This software thus also includes the copyright
6	* notice and license conditions from IBX.
7	*
8	* Except for those parts dervied from IBX, contents of this file are subject
9	* to the Initial Developer's Public License Version 1.0 (the "License"); you
10	* may not use this file except in compliance with the License. You may obtain a
11	* copy of the License here:
12	*
13	* http://www.firebirdsql.org/index.php?op=doc&id=idpl
14	*
15	* Software distributed under the License is distributed on an "AS
16	* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17	* implied. See the License for the specific language governing rights
18	* and limitations under the License.
19	*
20	* The Initial Developer of the Original Code is Tony Whyman.
21	*
22	* The Original Code is (C) 2016 Tony Whyman, MWA Software
23	* (http://www.mwasoftware.co.uk).
24	*
25	* All Rights Reserved.
26	*
27	* Contributor(s): ______________________________________.
28	*
29	*)
30	{************************************************************************}
31	{ }
32	{ Borland Delphi Visual Component Library }
33	{ InterBase Express core components }
34	{ }
35	{ Copyright (c) 1998-2000 Inprise Corporation }
36	{ }
37	{ InterBase Express is based in part on the product }
38	{ Free IB Components, written by Gregory H. Deatz for }
39	{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
40	{ Free IB Components is used under license. }
41	{ }
42	{ The contents of this file are subject to the InterBase }
43	{ Public License Version 1.0 (the "License"); you may not }
44	{ use this file except in compliance with the License. You }
45	{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
46	{ Software distributed under the License is distributed on }
47	{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
48	{ express or implied. See the License for the specific language }
49	{ governing rights and limitations under the License. }
50	{ The Original Code was created by InterBase Software Corporation }
51	{ and its successors. }
52	{ Portions created by Inprise Corporation are Copyright (C) Inprise }
53	{ Corporation. All Rights Reserved. }
54	{ Contributor(s): Jeff Overcash }
55	{ }
56	{ IBX For Lazarus (Firebird Express) }
57	{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
58	{ Portions created by MWA Software are copyright McCallum Whyman }
59	{ Associates Ltd 2011 - 2015 }
60	{ }
61	{************************************************************************}
62	unit FBTransaction;
63	{$IFDEF MSWINDOWS}
64	{$DEFINE WINDOWS}
65	{$ENDIF}
66
67	{$IFDEF FPC}
68	{$mode delphi}
69	{$interfaces COM}
70	{$ENDIF}
71
72	interface
73
74	uses
75	Classes, SysUtils, IB, FBParamBlock, FBActivityMonitor, FBClientAPI, FBOutputBlock;
76
77	type
78	{ TFBTransaction }
79
80	TFBTransaction = class(TActivityReporter, IActivityMonitor,ITransaction)
81	private
82	FFirebirdAPI: TFBClientAPI;
83	function GenerateTPB(sl: array of byte): ITPB;
84	protected
85	FTPB: ITPB;
86	FSeqNo: integer;
87	FDefaultCompletion: TTransactionCompletion;
88	FAttachments: array of IAttachment; {Keep reference to attachment - ensures
89	attachment cannot be freed before transaction}
90	FTransactionName: AnsiString;
91	FForeignHandle: boolean;
92	procedure CheckHandle;
93	function GetActivityIntf(att: IAttachment): IActivityMonitor; virtual; abstract;
94	function GetJournalIntf(Attachment: IAttachment): IJournallingHook;
95	procedure SetInterface(api: TFBClientAPI); virtual;
96	function GetTrInfo(ReqBuffer: PByte; ReqBufLen: integer): ITrInformation; virtual; abstract;
97	procedure InternalStartSingle(attachment: IAttachment); virtual; abstract;
98	procedure InternalStartMultiple; virtual; abstract;
99	procedure InternalCommit(Force: boolean); virtual; abstract;
100	procedure InternalCommitRetaining; virtual; abstract;
101	procedure InternalRollback(Force: boolean); virtual; abstract;
102	procedure InternalRollbackRetaining; virtual; abstract;
103	public
104	constructor Create(api: TFBClientAPI; Attachments: array of IAttachment; Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
105	constructor Create(api: TFBClientAPI; Attachments: array of IAttachment; TPB: ITPB; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
106	constructor Create(api: TFBClientAPI; Attachment: IAttachment; Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
107	constructor Create(api: TFBClientAPI; Attachment: IAttachment; TPB: ITPB; DefaultCompletion: TTransactionAction; aName: AnsiString); overload;
108	destructor Destroy; override;
109	procedure DoDefaultTransactionEnd(Force: boolean);
110	property FirebirdAPI: TFBClientAPI read FFirebirdAPI;
111
112	public
113	{ITransaction}
114	function getTPB: ITPB;
115	procedure PrepareForCommit;virtual; abstract;
116	procedure Commit(Force: boolean=false);
117	procedure CommitRetaining;
118	function GetInTransaction: boolean; virtual; abstract;
119	function GetIsReadOnly: boolean;
120	function GetTransactionID: integer;
121	function GetAttachmentCount: integer;
122	function GetAttachment(index: integer): IAttachment;
123	function GetJournalingActive(attachment: IAttachment): boolean;
124	function GetDefaultCompletion: TTransactionCompletion;
125	procedure Rollback(Force: boolean=false);
126	procedure RollbackRetaining;
127	procedure Start(DefaultCompletion: TTransactionCompletion=taCommit); overload;
128	procedure Start(TPB: ITPB; DefaultCompletion: TTransactionCompletion=taCommit); overload;
129	function GetTrInformation(Requests: array of byte): ITrInformation; overload;
130	function GetTrInformation(Request: byte): ITrInformation; overload;
131	function GetTransactionName: AnsiString;
132	procedure SetTransactionName(aValue: AnsiString);
133
134	property InTransaction: boolean read GetInTransaction;
135	property TransactionSeqNo: integer read FSeqNo;
136	end;
137
138	{The transaction user interface is used to force an action on the end of the
139	transaction.}
140
141	ITransactionUser = interface
142	['{156fcdc9-a326-44b3-a82d-f23c6fb9f97c}']
143	procedure TransactionEnding(aTransaction: ITransaction; Force: boolean);
144	end;
145
146	{ TTPBItem }
147
148	TTPBItem = class(TParamBlockItem,ITPBItem)
149	public
150	function getParamTypeName: AnsiString; override;
151	end;
152
153	{ TTPB }
154
155	TTPB = class (TCustomParamBlock<TTPBItem,ITPBItem>, ITPB)
156	protected
157	function LookupItemType(ParamTypeName: AnsiString): byte; override;
158	public
159	constructor Create(api: TFBClientAPI);
160	function GetParamTypeName(ParamType: byte): Ansistring;
161	{$IFDEF FPC}
162	function ITPB.GetDPBParamTypeName = GetParamTypeName;
163	{$ELSE}
164	function GetDPBParamTypeName(ParamType: byte): Ansistring;
165	{$ENDIF}
166	function AsText: AnsiString;
167	end;
168
169	{$IFDEF FPC}
170	TTrInfoItem = class;
171
172	{ TTrInfoItem }
173
174	TTrInfoItem = class(TOutputBlockItemGroup<TTrInfoItem,ITrInfoItem>,ITrInfoItem)
175	{$ELSE}
176	TTrInfoItem = class(TOutputBlockItemGroup<TOutputBlockItem,ITrInfoItem>,ITrInfoItem)
177	{$ENDIF}
178	public
179	procedure DecodeTraIsolation(var IsolationType, RecVersion: byte);
180	end;
181
182	{ TTrInformation }
183
184	TTrInformation = class(TCustomOutputBlock<TTrInfoItem,ITrInfoItem>, ITrInformation)
185	protected
186	procedure DoParseBuffer; override;
187	public
188	constructor Create(api: TFBClientAPI; aSize: integer = DefaultBufferSize);
189	{$IFNDEF FPC}
190	function Find(ItemType: byte): ITrInfoItem;
191	{$ENDIF}
192	end;
193
194
195	implementation
196
197	uses FBMessages;
198
199	const
200	isc_tpb_last_tpb_constant = isc_tpb_at_snapshot_number;
201
202	TPBConstantNames: array[1..isc_tpb_last_tpb_constant] of string = (
203	'consistency',
204	'concurrency',
205	'shared',
206	'protected',
207	'exclusive',
208	'wait',
209	'nowait',
210	'read',
211	'write',
212	'lock_read',
213	'lock_write',
214	'verb_time',
215	'commit_time',
216	'ignore_limbo',
217	'read_committed',
218	'autocommit',
219	'rec_version',
220	'no_rec_version',
221	'restart_requests',
222	'no_auto_undo',
223	'lock_timeout',
224	'read_consistency',
225	'at_snapshot_number'
226	);
227
228	{ TFBTransaction }
229
230	function TFBTransaction.GenerateTPB(sl: array of byte): ITPB;
231	var
232	i: Integer;
233	begin
234	Result := TTPB.Create(FFirebirdAPI);
235	for i := 0 to Length(sl) - 1 do
236	Result.Add(sl[i]);
237	end;
238
239	procedure TFBTransaction.CheckHandle;
240	begin
241	if not InTransaction then
242	IBError(ibxeNotInTransaction,[]);
243	end;
244
245	function TFBTransaction.GetJournalIntf(Attachment: IAttachment): IJournallingHook;
246	begin
247	Attachment.QueryInterface(IJournallingHook,Result)
248	end;
249
250	procedure TFBTransaction.SetInterface(api: TFBClientAPI);
251	begin
252	FFirebirdAPI := api;
253	end;
254
255	constructor TFBTransaction.Create(api: TFBClientAPI; Attachments: array of IAttachment;
256	Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString);
257	begin
258	Create(api, Attachments,GenerateTPB(Params), DefaultCompletion, aName);
259	end;
260
261	constructor TFBTransaction.Create(api: TFBClientAPI; Attachments: array of IAttachment; TPB: ITPB;
262	DefaultCompletion: TTransactionAction; aName: AnsiString);
263	var
264	i: Integer;
265	begin
266	inherited Create(nil);
267	FTransactionName := aName;
268	SetInterface(api);
269	if Length(Attachments) = 0 then
270	IBError(ibxeEmptyAttachmentsList,[nil]);
271
272	{make sure all attachments use same Firebird API}
273	for i := 0 to Length(Attachments) - 1 do
274	if Attachments[i].getFirebirdAPI.GetFBLibrary.GetHandle <> FFirebirdAPI.GetFBLibrary.GetHandle then
275	IBError(ibxeDifferentAPIs,[nil]);
276
277	SetLength(FAttachments,Length(Attachments));
278	for i := 0 to Length(Attachments) - 1 do
279	begin
280	AddMonitor(GetActivityIntf(Attachments[i]));
281	FAttachments[i] := Attachments[i];
282	end;
283	FTPB := TPB;
284	Start(DefaultCompletion);
285	end;
286
287	constructor TFBTransaction.Create(api: TFBClientAPI; Attachment: IAttachment;
288	Params: array of byte; DefaultCompletion: TTransactionAction; aName: AnsiString);
289	begin
290	Create(api,Attachment,GenerateTPB(Params),DefaultCompletion,aName);
291	end;
292
293	constructor TFBTransaction.Create(api: TFBClientAPI; Attachment: IAttachment; TPB: ITPB;
294	DefaultCompletion: TTransactionAction; aName: AnsiString);
295	begin
296	inherited Create(nil);
297	SetInterface(api);
298	AddMonitor(GetActivityIntf(Attachment));
299	SetLength(FAttachments,1);
300	FAttachments[0] := Attachment;
301	FTPB := TPB;
302	FTransactionName := aName;
303	Start(DefaultCompletion);
304	end;
305
306	destructor TFBTransaction.Destroy;
307	begin
308	DoDefaultTransactionEnd(false);
309	inherited Destroy;
310	end;
311
312	procedure TFBTransaction.DoDefaultTransactionEnd(Force: boolean);
313	var i: integer;
314	intf: IUnknown;
315	user: ITransactionUser;
316	begin
317	if InTransaction and not FForeignHandle then
318	begin
319	for i := 0 to InterfaceCount - 1 do
320	begin
321	intf := GetInterface(i);
322	if (intf <> nil) and (intf.QueryInterface(ITransactionUser,user) = S_OK) then
323	user.TransactionEnding(self,Force);
324	end;
325	case FDefaultCompletion of
326	taRollback:
327	Rollback(Force);
328	taCommit:
329	Commit(Force);
330	end;
331	end;
332	end;
333
334	function TFBTransaction.getTPB: ITPB;
335	begin
336	Result := FTPB;
337	end;
338
339	procedure TFBTransaction.Commit(Force: boolean);
340	var i: integer;
341	TransactionID: integer;
342	TransactionEndNeeded: array of boolean;
343	begin
344	if not GetInTransaction then Exit;
345
346	if FForeignHandle then
347	IBError(ibxeTransactionNotOwned,[nil]);
348
349	SetLength(TransactionEndNeeded,Length(FAttachments));
350	TransactionID := GetTransactionID;
351	for i := 0 to Length(FAttachments) - 1 do
352	if (FAttachments[i] <> nil) then
353	TransactionEndNeeded[i] := GetJournalingActive(FAttachments[i])
354	else
355	TransactionEndNeeded[i] := false;
356	InternalCommit(Force);
357	for i := 0 to Length(FAttachments) - 1 do
358	if TransactionEndNeeded[i] then
359	GetJournalIntf(FAttachments[i]).TransactionEnd(TransactionID, TACommit);
360	end;
361
362	procedure TFBTransaction.CommitRetaining;
363	var i: integer;
364	TransactionID: integer;
365	begin
366	if not GetInTransaction then Exit;
367
368	TransactionID := GetTransactionID;
369	InternalCommitRetaining;
370	for i := 0 to Length(FAttachments) - 1 do
371	if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
372	GetJournalIntf(FAttachments[i]).TransactionRetained(self,TransactionID, TACommitRetaining);
373	end;
374
375	function TFBTransaction.GetIsReadOnly: boolean;
376	var Info: ITrInformation;
377	begin
378	Info := GetTrInformation(isc_info_tra_access);
379	if (Info.Count > 0) and (Info[0].getItemType = isc_info_tra_access) then
380	Result := Info[0].getAsInteger = isc_info_tra_readonly
381	else
382	Result := false;
383	end;
384
385	function TFBTransaction.GetTransactionID: integer;
386	var Info: ITrInformation;
387	begin
388	Result := -1;
389	Info := GetTrInformation(isc_info_tra_id);
390	if (Info.Count > 0) and (Info[0].getItemType = isc_info_tra_id) then
391	Result := Info[0].getAsInteger;
392	end;
393
394	function TFBTransaction.GetAttachmentCount: integer;
395	begin
396	Result := Length(FAttachments);
397	end;
398
399	function TFBTransaction.GetAttachment(index: integer): IAttachment;
400	begin
401	if (index >= 0) and (index < Length(FAttachments)) then
402	Result := FAttachments[index]
403	else
404	IBError(ibxeAttachmentListIndexError,[index]);
405	end;
406
407	function TFBTransaction.GetJournalingActive(attachment: IAttachment): boolean;
408	begin
409	Result := false;
410	if (attachment = nil) and (length(FAttachments) > 0) then
411	attachment := FAttachments[0];
412	if attachment <> nil then
413	with attachment do
414	Result := self.GetInTransaction and JournalingActive and
415	((((joReadOnlyTransactions in GetJournalOptions) and self.GetIsReadOnly)) or
416	((joReadWriteTransactions in GetJournalOptions) and not self.GetIsReadOnly));
417	end;
418
419	function TFBTransaction.GetDefaultCompletion: TTransactionCompletion;
420	begin
421	Result := FDefaultCompletion;
422	end;
423
424	procedure TFBTransaction.Rollback(Force: boolean);
425	var i: integer;
426	TransactionID: integer;
427	TransactionEndNeeded: array of boolean;
428	begin
429	if not GetInTransaction then Exit;
430
431	if FForeignHandle then
432	IBError(ibxeTransactionNotOwned,[nil]);
433
434	SetLength(TransactionEndNeeded,Length(FAttachments));
435	TransactionID := GetTransactionID;
436	for i := 0 to Length(FAttachments) - 1 do
437	if (FAttachments[i] <> nil) then
438	TransactionEndNeeded[i] := GetJournalingActive(FAttachments[i])
439	else
440	TransactionEndNeeded[i] := false;
441	InternalRollback(Force);
442	for i := 0 to Length(FAttachments) - 1 do
443	if TransactionEndNeeded[i] then
444	GetJournalIntf(FAttachments[i]).TransactionEnd(TransactionID, TARollback);
445	end;
446
447	procedure TFBTransaction.RollbackRetaining;
448	var i: integer;
449	TransactionID: integer;
450	begin
451	if not GetInTransaction then Exit;
452
453	TransactionID := GetTransactionID;
454	InternalRollbackRetaining;
455	for i := 0 to Length(FAttachments) - 1 do
456	if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
457	GetJournalIntf(FAttachments[i]).TransactionRetained(self,TransactionID,TARollbackRetaining);
458	end;
459
460	procedure TFBTransaction.Start(DefaultCompletion: TTransactionCompletion);
461	var i: integer;
462	begin
463	if GetInTransaction then
464	Exit;
465
466	FDefaultCompletion := DefaultCompletion;
467
468	if Length(FAttachments) = 1 then
469	InternalStartSingle(FAttachments[0])
470	else
471	InternalStartMultiple;
472	for i := 0 to Length(FAttachments) - 1 do
473	if (FAttachments[i] <> nil) and GetJournalingActive(FAttachments[i]) then
474	GetJournalIntf(FAttachments[i]).TransactionStart(self);
475	Inc(FSeqNo);
476	end;
477
478	procedure TFBTransaction.Start(TPB: ITPB; DefaultCompletion: TTransactionCompletion
479	);
480	begin
481	FTPB := TPB;
482	Start(DefaultCompletion);
483	end;
484
485	function TFBTransaction.GetTrInformation(Requests: array of byte
486	): ITrInformation;
487	var ReqBuffer: PByte;
488	i: integer;
489	begin
490	CheckHandle;
491	if Length(Requests) = 1 then
492	Result := GetTrInformation(Requests[0])
493	else
494	begin
495	GetMem(ReqBuffer,Length(Requests));
496	try
497	for i := 0 to Length(Requests) - 1 do
498	ReqBuffer[i] := Requests[i];
499
500	Result := GetTrInfo(ReqBuffer,Length(Requests));
501
502	finally
503	FreeMem(ReqBuffer);
504	end;
505	end;
506	end;
507
508	function TFBTransaction.GetTrInformation(Request: byte): ITrInformation;
509	begin
510	CheckHandle;
511	Result := GetTrInfo(@Request,1);
512	end;
513
514	function TFBTransaction.GetTransactionName: AnsiString;
515	begin
516	Result := FTransactionName;
517	end;
518
519	procedure TFBTransaction.SetTransactionName(aValue: AnsiString);
520	begin
521	FTransactionName := aValue;
522	end;
523
524	{ TTPBItem }
525
526	function TTPBItem.getParamTypeName: AnsiString;
527	begin
528	Result := TPBPrefix + TPBConstantNames[getParamType];
529	end;
530
531
532	{TTPB}
533
534	constructor TTPB.Create(api: TFBClientAPI);
535	begin
536	inherited Create(api);
537	FDataLength := 1;
538	FBuffer^ := isc_tpb_version3;
539	end;
540
541	function TTPB.GetParamTypeName(ParamType: byte): Ansistring;
542	begin
543	if ParamType <= isc_tpb_last_tpb_constant then
544	Result := TPBPrefix + TPBConstantNames[ParamType]
545	else
546	Result := '';
547	end;
548
549	function TTPB.AsText: AnsiString;
550	var i: integer;
551	begin
552	Result := '[';
553	for i := 0 to getCount - 1 do
554	begin
555	Result := Result + GetParamTypeName(getItems(i).getParamType);
556	if i < getCount - 1 then
557	Result := Result + ',';
558	end;
559	Result := Result + ']';
560	end;
561
562	{$IFNDEF FPC}
563	function TTPB.GetDPBParamTypeName(ParamType: byte): Ansistring;
564	begin
565	Result := GetParamTypeName(ParamType);
566	end;
567	{$ENDIF}
568
569
570	function TTPB.LookupItemType(ParamTypeName: AnsiString): byte;
571	var i: byte;
572	begin
573	Result := 0;
574	ParamTypeName := LowerCase(ParamTypeName);
575	if (Pos(TPBPrefix, ParamTypeName) = 1) then
576	Delete(ParamTypeName, 1, Length(TPBPrefix));
577
578	for i := 1 to isc_tpb_last_tpb_constant do
579	if (ParamTypeName = TPBConstantNames[i]) then
580	begin
581	Result := i;
582	break;
583	end;
584	end;
585
586	{ TTrInfoItem }
587
588	procedure TTrInfoItem.DecodeTraIsolation(var IsolationType, RecVersion: byte);
589	begin
590	with FFirebirdClientAPI, ItemData^ do
591	if getItemType = isc_info_tra_isolation then
592	begin
593	if FDataLength = 1 then
594	begin
595	IsolationType := getAsInteger;
596	RecVersion := 0;
597	end
598	else
599	begin
600	IsolationType := (FBufPtr + 3)^;
601	RecVersion := (FBufPtr + 4)^;
602	end
603	end
604	else
605	IBError(ibxeInfoBufferTypeError,[integer(FBufPtr^)]);
606	end;
607
608	{ TTrInformation }
609
610	procedure TTrInformation.DoParseBuffer;
611	var P: PByte;
612	index: integer;
613	begin
614	P := Buffer;
615	index := 0;
616	SetLength(FItems,0);
617	while (P^ <> isc_info_end) and (P < Buffer + getBufSize) do
618	begin
619	SetLength(FItems,index+1);
620	case byte(P^) of
621	isc_info_tra_id,
622	isc_info_tra_oldest_interesting,
623	isc_info_tra_oldest_active,
624	isc_info_tra_oldest_snapshot,
625	fb_info_tra_snapshot_number,
626	isc_info_tra_lock_timeout:
627	FItems[index] := AddIntegerItem(P);
628
629	isc_info_tra_isolation,
630	{return transaction isolation mode of current transaction.
631	format of returned clumplets is following:
632
633	isc_info_tra_isolation,
634	1, isc_info_tra_consistency \| isc_info_tra_concurrency
635	\|
636	2, isc_info_tra_read_committed,
637	isc_info_tra_no_rec_version \| isc_info_tra_rec_version
638
639	i.e. for read committed transactions returned 2 items while for
640	other transactions returned 1 item}
641
642	isc_info_tra_access:
643	FItems[index] := AddIntegerItem(P);
644	fb_info_tra_dbpath:
645	FItems[index] := AddStringItem(P);
646	else
647	FItems[index] := AddItem(P);
648	end;
649	P := P + FItems[index]^.FSize;
650	Inc(index);
651	end;
652	end;
653
654	constructor TTrInformation.Create(api: TFBClientAPI; aSize: integer);
655	begin
656	inherited Create(api,aSize);
657	FIntegerType := dtInteger;
658	end;
659
660	{$IFNDEF FPC}
661	function TTrInformation.Find(ItemType: byte): ITrInfoItem;
662	begin
663	Result := inherited Find(ItemType);
664	if Result.GetSize = 0 then
665	Result := nil;
666	end;
667	{$ENDIF}
668
669	end.
670