(*
 *  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 FBClientAPI;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$codepage UTF8}
{$interfaces COM}
{$ENDIF}

interface

uses
  Classes,
    {$IFDEF WINDOWS}Windows, {$ENDIF}
    {$IFDEF FPC} Dynlibs, {$ENDIF}
   IB, IBHeader, FBActivityMonitor, FBMessages, IBExternals;

{For Linux see result of GetFirebirdLibList method}
{$IFDEF DARWIN}
const
FIREBIRD_SO2 = 'libfbclient.dylib';
{$ENDIF}
{$IFDEF WINDOWS}
const
IBASE_DLL = 'gds32.dll';
FIREBIRD_CLIENT = 'fbclient.dll'; {do not localize}
FIREBIRD_EMBEDDED = 'fbembed.dll';
{$ENDIF}

{$IFNDEF FPC}
type
  TLibHandle = THandle;

const
  NilHandle = 0;
  DirectorySeparator = '\';
{$ENDIF}

type
  TStatusVector              = array[0..19] of NativeInt;
  PStatusVector              = ^TStatusVector;

  TFBClientAPI = class;

  { TFBStatus }

  TFBStatus = class(TFBInterfacedObject)
  private
    FIBDataBaseErrorMessages: TIBDataBaseErrorMessages;
  protected
    FOwner: TFBClientAPI;
  public
    constructor Create(aOwner: TFBClientAPI);
    function StatusVector: PStatusVector; virtual; abstract;

    {IStatus}
    function GetIBErrorCode: Long;
    function Getsqlcode: Long;
    function GetMessage: AnsiString;
    function CheckStatusVector(ErrorCodes: array of TFBStatusCode): Boolean;
    function GetIBDataBaseErrorMessages: TIBDataBaseErrorMessages;
    procedure SetIBDataBaseErrorMessages(Value: TIBDataBaseErrorMessages);
  end;

  { TFBClientAPI }

  TFBClientAPI = class(TFBInterfacedObject)
  private
    FOwnsIBLibrary: boolean;
    class var FIBCS: TRTLCriticalSection;
    procedure LoadIBLibrary;
  protected
    class var FFBLibraryName: string;
    class var IBLibrary: TLibHandle;
    {$IFDEF WINDOWS}
    class var FFBLibraryPath: string;
    {$ENDIF}
    function GetProcAddr(ProcName: PAnsiChar): Pointer;
    function GetOverrideLibName: string;
    {$IFDEF UNIX}
    function GetFirebirdLibList: string; virtual; abstract;
    {$ENDIF}
    procedure LoadInterface; virtual;
  public
    {Taken from legacy API}
    isc_sqlcode: Tisc_sqlcode;
    isc_sql_interprete: Tisc_sql_interprete;
    isc_interprete: Tisc_interprete;
    isc_event_counts: Tisc_event_counts;
    isc_event_block: Tisc_event_block;
    isc_free: Tisc_free;

    constructor Create;
    destructor Destroy; override;
    procedure IBAlloc(var P; OldSize, NewSize: Integer);
    procedure IBDataBaseError;
    procedure SetupEnvironment;

    {Encode/Decode}
    procedure EncodeInteger(aValue: integer; len: integer; buffer: PByte);
    function DecodeInteger(bufptr: PByte; len: short): integer; virtual; abstract;
    procedure SQLEncodeDate(aDate: TDateTime; bufptr: PByte); virtual; abstract;
    function SQLDecodeDate(byfptr: PByte): TDateTime; virtual; abstract;
    procedure SQLEncodeTime(aTime: TDateTime; bufptr: PByte); virtual; abstract;
    function SQLDecodeTime(bufptr: PByte): TDateTime;  virtual; abstract;
    procedure SQLEncodeDateTime(aDateTime: TDateTime; bufptr: PByte); virtual; abstract;
    function SQLDecodeDateTime(bufptr: PByte): TDateTime; virtual; abstract;


    {IFirebirdAPI}
    function GetStatus: IStatus; virtual; abstract;
    function IsLibraryLoaded: boolean;
    function IsEmbeddedServer: boolean; virtual; abstract;
    function GetLibraryName: string;
end;

var FirebirdClientAPI: TFBClientAPI = nil;

implementation

uses IBUtils, Registry, {$IFDEF Unix} initc, {$ENDIF}
{$IFDEF FPC}
{$IFDEF WINDOWS }
WinDirs,
{$ENDIF}
{$ELSE}
 ShlObj,
{$ENDIF}
SysUtils;

{$IFDEF UNIX}
{$I 'include/uloadlibrary.inc'}
{$ELSE}
{$I 'include/wloadlibrary.inc'}
{$ENDIF}

  {$IFDEF Unix}
  {SetEnvironmentVariable doesn't exist so we have to use C Library}
  function setenv(name:Pchar; value:Pchar; replace:integer):integer;cdecl;external clib name 'setenv';
  function unsetenv(name:Pchar):integer;cdecl;external clib name 'unsetenv';
  function SetEnvironmentVariable(name:PAnsiChar; value:PAnsiChar):boolean;
  // Set environment variable; if empty string given, remove it.
  begin
    result:=false; //assume failure
    if value = '' then
    begin
      // Assume user wants to remove variable.
      if unsetenv(name)=0 then result:=true;
    end
    else
    begin
      // Non empty so set the variable
      if setenv(name, value, 1)=0 then result:=true;
    end;
  end;
  {$ENDIF}

{ TFBClientAPI }

constructor TFBClientAPI.Create;
begin
  inherited Create;
  LoadIBLibrary;
  if (IBLibrary <> NilHandle) then
  begin
    SetupEnvironment;
    LoadInterface;
  end;
  FirebirdClientAPI := self;
end;

destructor TFBClientAPI.Destroy;
begin
  FirebirdClientAPI := nil;
  if FOwnsIBLibrary and (IBLibrary <> NilHandle) then
    FreeLibrary(IBLibrary);
  IBLibrary := NilHandle;
  inherited Destroy;
end;

procedure TFBClientAPI.IBAlloc(var P; OldSize, NewSize: Integer);
var
  i: Integer;
begin
  ReallocMem(Pointer(P), NewSize);
  for i := OldSize to NewSize - 1 do PAnsiChar(P)[i] := #0;
end;

procedure TFBClientAPI.IBDataBaseError;
begin
  raise EIBInterBaseError.Create(GetStatus);
end;

{Under Unixes, if using an embedded server then set up local TMP and LOCK Directories}

procedure TFBClientAPI.SetupEnvironment;
var TmpDir: AnsiString;
begin
  {$IFDEF UNIX}
    TmpDir := GetTempDir +
        DirectorySeparator + 'firebird_' + sysutils.GetEnvironmentVariable('USER');
    if sysutils.GetEnvironmentVariable('FIREBIRD_TMP') = '' then
    begin
      if not DirectoryExists(tmpDir) then
        mkdir(tmpDir);
      SetEnvironmentVariable('FIREBIRD_TMP',PAnsiChar(TmpDir));
    end;
    if sysutils.GetEnvironmentVariable('FIREBIRD_LOCK') = '' then
    begin
      if not DirectoryExists(tmpDir) then
        mkdir(tmpDir);
      SetEnvironmentVariable('FIREBIRD_LOCK',PAnsiChar(TmpDir));
    end;
  {$ENDIF}
end;

procedure TFBClientAPI.EncodeInteger(aValue: integer; len: integer; buffer: PByte);
begin
  while len > 0 do
  begin
    buffer^ := aValue and $FF;
    Inc(buffer);
    Dec(len);
    aValue := aValue shr 8;
  end;
end;

function TFBClientAPI.IsLibraryLoaded: boolean;
begin
  Result := IBLibrary <> NilHandle;
end;

function TFBClientAPI.GetProcAddr(ProcName: PAnsiChar): Pointer;
begin
  Result := GetProcAddress(IBLibrary, ProcName);
  if not Assigned(Result) then
    raise Exception.CreateFmt(SFirebirdAPIFuncNotFound,[ProcName]);
end;

function TFBClientAPI.GetOverrideLibName: string;
begin
  Result := '';
  if AllowUseOfFBLIB then
    Result := GetEnvironmentVariable('FBLIB');
  if Result = '' then
  begin
    if assigned(OnGetLibraryName) then
      OnGetLibraryName(Result)
  end;
end;

procedure TFBClientAPI.LoadInterface;
begin
  isc_sqlcode := GetProcAddr('isc_sqlcode'); {do not localize}
  isc_sql_interprete := GetProcAddr('isc_sql_interprete'); {do not localize}
  isc_interprete := GetProcAddr('isc_interprete'); {do not localize}
  isc_event_counts := GetProcAddr('isc_event_counts'); {do not localize}
  isc_event_block := GetProcAddr('isc_event_block'); {do not localize}
  isc_free := GetProcAddr('isc_free'); {do not localize}
end;

function TFBClientAPI.GetLibraryName: string;
begin
  Result := FFBLibraryName;
end;

const
  IBLocalBufferLength = 512;
  IBBigLocalBufferLength = IBLocalBufferLength * 2;
  IBHugeLocalBufferLength = IBBigLocalBufferLength * 20;

{ TFBStatus }

constructor TFBStatus.Create(aOwner: TFBClientAPI);
begin
  inherited Create;
  FOwner := aOwner;
  FIBDataBaseErrorMessages := [ShowSQLMessage, ShowIBMessage];
end;

function TFBStatus.GetIBErrorCode: Long;
begin
  Result := StatusVector^[1];
end;

function TFBStatus.Getsqlcode: Long;
begin
  with FOwner do
    Result := isc_sqlcode(PISC_STATUS(StatusVector));
end;

function TFBStatus.GetMessage: AnsiString;
var local_buffer: array[0..IBHugeLocalBufferLength - 1] of AnsiChar;
    IBDataBaseErrorMessages: TIBDataBaseErrorMessages;
    sqlcode: Long;
    psb: PStatusVector;
begin
  Result := '';
  IBDataBaseErrorMessages := FIBDataBaseErrorMessages;
  sqlcode := Getsqlcode;
  if (ShowSQLCode in IBDataBaseErrorMessages) then
    Result := Result + 'SQLCODE: ' + IntToStr(sqlcode); {do not localize}

  Exclude(IBDataBaseErrorMessages, ShowSQLMessage);
  if (ShowSQLMessage in IBDataBaseErrorMessages) then
  begin
    with FOwner do
      isc_sql_interprete(sqlcode, local_buffer, IBLocalBufferLength);
    if (ShowSQLCode in FIBDataBaseErrorMessages) then
      Result := Result + CRLF;
    Result := Result + strpas(local_buffer);
  end;

  if (ShowIBMessage in IBDataBaseErrorMessages) then
  begin
    if (ShowSQLCode in IBDataBaseErrorMessages) or
       (ShowSQLMessage in IBDataBaseErrorMessages) then
      Result := Result + CRLF;
    psb := StatusVector;
    with FOwner do
    while (isc_interprete(@local_buffer, @psb) > 0) do
    begin
      if (Result <> '') and (Result[Length(Result)] <> LF) then
        Result := Result + CRLF;
      Result := Result + strpas(local_buffer);
    end;
  end;
  if (Result <> '') and (Result[Length(Result)] = '.') then
    Delete(Result, Length(Result), 1);
end;

function TFBStatus.CheckStatusVector(ErrorCodes: array of TFBStatusCode
  ): Boolean;
var
  p: PISC_STATUS;
  i: Integer;
  procedure NextP(i: Integer);
  begin
    p := PISC_STATUS(PAnsiChar(p) + (i * SizeOf(ISC_STATUS)));
  end;
begin
  p := PISC_STATUS(StatusVector);
  result := False;
  while (p^ <> 0) and (not result) do
    case p^ of
      3: NextP(3);
      1, 4:
      begin
        NextP(1);
        i := 0;
        while (i <= High(ErrorCodes)) and (not result) do
        begin
          result := p^ = ErrorCodes[i];
          Inc(i);
        end;
        NextP(1);
      end;
      else
        NextP(2);
    end;
end;

function TFBStatus.GetIBDataBaseErrorMessages: TIBDataBaseErrorMessages;
begin
  EnterCriticalSection(TFBClientAPI.FIBCS);
  try
    result := FIBDataBaseErrorMessages;
  finally
    LeaveCriticalSection(TFBClientAPI.FIBCS);
  end;
end;

procedure TFBStatus.SetIBDataBaseErrorMessages(Value: TIBDataBaseErrorMessages);
begin
  EnterCriticalSection(TFBClientAPI.FIBCS);
  try
    FIBDataBaseErrorMessages := Value;
  finally
    LeaveCriticalSection(TFBClientAPI.FIBCS);
  end;
end;

initialization
  TFBClientAPI.IBLibrary := NilHandle;
  {$IFNDEF FPC}
  InitializeCriticalSection(TFBClientAPI.FIBCS);
  {$ELSE}
  InitCriticalSection(TFBClientAPI.FIBCS);
  {$ENDIF}

finalization
  {$IFNDEF FPC}
  DeleteCriticalSection(TFBClientAPI.FIBCS);
  {$ELSE}
  DoneCriticalSection(TFBClientAPI.FIBCS);
  {$ENDIF}
  if TFBClientAPI.IBLibrary <> NilHandle then
  begin
    FreeLibrary(TFBClientAPI.IBLibrary);
    TFBClientAPI.IBLibrary := NilHandle;
    TFBClientAPI.FFBLibraryName := '';
  end;

end.