{
    This file is part of the Free Pascal Classes Library (FCL).
    Copyright (c) 2006 by the Free Pascal development team

    SQLite3 connection for SQLDB

    See the File COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}
 
{ 
  Based on an implementation by Martin Schreiber, part of MSEIDE.
  Reworked all code so it conforms to FCL coding standards.
} 
 
unit sqlite3conn;
{$mode objfpc}
{$h+}

interface

uses
  classes, db, bufdataset, sqldb, sqlite3dyn, types;

const
  sqliteerrormax = 99;
 
type
  PDateTime = ^TDateTime;
  
  TSqliteOption = (sloTransactions,sloDesignTransactions);
  TSqliteOptions = set of TSqliteOption;
 
  TStringArray = Array of string;
  PStringArray = ^TStringArray;
 
  TArrayStringArray = Array of TStringArray;
  PArrayStringArray = ^TArrayStringArray;
 
  { TSQLite3Connection }

  TSQLite3Connection = class(TSQLConnection)
  private
    fhandle: psqlite3;
    foptions: TSQLiteOptions;
    procedure setoptions(const avalue: tsqliteoptions);
  protected
    function stringquery(const asql: string): TStringArray;
    function stringsquery(const asql: string): TArrayStringArray;
    procedure checkerror(const aerror: integer);
    
    procedure DoInternalConnect; override;
    procedure DoInternalDisconnect; override;
    function GetHandle : pointer; override;
 
    Function AllocateCursorHandle : TSQLCursor; override;
                        //aowner used as blob cache
    Procedure DeAllocateCursorHandle(var cursor : TSQLCursor); override;
    Function AllocateTransactionHandle : TSQLHandle; override;
 
    procedure PrepareStatement(cursor: TSQLCursor; ATransaction : TSQLTransaction; 
                          buf: string; AParams : TParams); override;
    procedure Execute(cursor: TSQLCursor;atransaction:tSQLtransaction; AParams : TParams); override;
    function Fetch(cursor : TSQLCursor) : boolean; override;
    procedure AddFieldDefs(cursor: TSQLCursor; FieldDefs : TfieldDefs); override;
    procedure UnPrepareStatement(cursor : TSQLCursor); override;
 
    procedure FreeFldBuffers(cursor : TSQLCursor); override;
    function LoadField(cursor : TSQLCursor;FieldDef : TfieldDef;buffer : pointer; out CreateBlob : boolean) : boolean; override;
           //if bufsize < 0 -> buffer was to small, should be -bufsize
    function GetTransactionHandle(trans : TSQLHandle): pointer; override;
    function Commit(trans : TSQLHandle) : boolean; override;
    function RollBack(trans : TSQLHandle) : boolean; override;
    function StartdbTransaction(trans : TSQLHandle; aParams : string) : boolean; override;
    procedure CommitRetaining(trans : TSQLHandle); override;
    procedure RollBackRetaining(trans : TSQLHandle); override;
    procedure LoadBlobIntoBuffer(FieldDef: TFieldDef;ABlobBuf: PBufBlobField; cursor: TSQLCursor; ATransaction : TSQLTransaction); override;
    // New methods
    procedure execsql(const asql: string);
    procedure UpdateIndexDefs(var IndexDefs : TIndexDefs; const TableName : string); // Differs from SQLDB.
    function  getprimarykeyfield(const atablename: string; const acursor: tsqlcursor): string; 
    function RowsAffected(cursor: TSQLCursor): TRowsCount; override;
    function GetSchemaInfoSQL(SchemaType : TSchemaType; SchemaObjectName, SchemaPattern : string) : string; override;
    function StrToStatementType(s : string) : TStatementType; override;
  public
    function GetInsertID: int64; 
    procedure GetFieldNames(const TableName : string; List :  TStrings); override;
  published
    property Options: TSqliteOptions read FOptions write SetOptions;
  end;
 
implementation

uses
  dbconst, sysutils, typinfo, dateutils;
 
type

 TStorageType = (stNone,stInteger,stFloat,stText,stBlob,stNull);
 
 TSQLite3Cursor = class(tsqlcursor)
  private
   fhandle : psqlite3;
   fstatement: psqlite3_stmt;
   ftail: pchar;
   fstate: integer;
   fparambinding: array of Integer;
   procedure checkerror(const aerror: integer);
   procedure bindparams(AParams : TParams);
   Procedure Prepare(Buf : String; APArams : TParams);
   Procedure UnPrepare;
   Procedure Execute;
   Function Fetch : Boolean;
 public
   RowsAffected : Largeint;
 end;

procedure freebindstring(astring: pointer); cdecl;
begin
  StrDispose(AString);
end;

procedure TSQLite3Cursor.checkerror(const aerror: integer);

Var
  S : String;

begin
 if (aerror<>sqlite_ok) then 
   begin
   S:=strpas(sqlite3_errmsg(fhandle));
   DatabaseError(S);
   end;
end;

Procedure TSQLite3Cursor.bindparams(AParams : TParams);

  Function PCharStr(Const S : String) : PChar;
  
  begin
    Result:=StrAlloc(Length(S)+1);
    If (Result<>Nil) then
      StrPCopy(Result,S);
  end;
  
Var
  I : Integer;
  P : TParam;  
  pc : pchar;
  str1: string;
  cu1: currency;
  do1: double;
  parms : array of Integer;
  
begin
  for I:=1  to high(fparambinding)+1 do 
    begin
    P:=aparams[fparambinding[I-1]];
    if P.isnull then 
      checkerror(sqlite3_bind_null(fstatement,I))
    else 
      case P.datatype of
        ftinteger,
        ftboolean,
        ftsmallint: checkerror(sqlite3_bind_int(fstatement,I,p.asinteger));
        ftword:     checkerror(sqlite3_bind_int(fstatement,I,P.asword));
        ftlargeint: checkerror(sqlite3_bind_int64(fstatement,I,P.aslargeint));
        ftbcd: begin
               cu1:= P.ascurrency;
               checkerror(sqlite3_bind_int64(fstatement,I,pint64(@cu1)^));
               end;
        ftfloat,
        ftcurrency,
        ftdatetime,
        ftdate,
        fttime: begin
                do1:= P.asfloat;
                checkerror(sqlite3_bind_double(fstatement,I,do1));
                end;
        ftstring: begin
                  str1:= p.asstring;
                  checkerror(sqlite3_bind_text(fstatement,I,pcharstr(str1), length(str1),@freebindstring));
                  end;
        ftblob: begin
                str1:= P.asstring;
                checkerror(sqlite3_bind_blob(fstatement,I,pcharstr(str1), length(str1),@freebindstring));
                end; 
      else 
        databaseerror('Parameter type '+getenumname(typeinfo(tfieldtype),ord(P.datatype))+' not supported.');
      end; { Case }
    end;   
end;

Procedure TSQLite3Cursor.Prepare(Buf : String; APArams : TParams);

begin
  if assigned(aparams) and (aparams.count > 0) then 
    buf := aparams.parsesql(buf,false,false,false,psinterbase,fparambinding);
  checkerror(sqlite3_prepare(fhandle,pchar(buf),length(buf),@fstatement,@ftail));
end;

Procedure TSQLite3Cursor.UnPrepare;

begin
  sqlite3_finalize(fstatement); // No check.
end;

Procedure TSQLite3Cursor.Execute;

var
 wo1: word;

begin
{$ifdef i386}
  wo1:= get8087cw;
  set8087cw(wo1 or $1f);             //mask exceptions, Sqlite3 has overflow
  Try  // Why do people always forget this ??
{$endif}
    fstate:= sqlite3_step(fstatement);
{$ifdef i386}
  finally  
    set8087cw(wo1);                    //restore
  end;
{$endif}  
  if (fstate<=sqliteerrormax) then 
    checkerror(sqlite3_reset(fstatement));
  RowsAffected:=sqlite3_changes(fhandle);
  if (fstate=sqlite_row) then 
    fstate:= sqliteerrormax; //first row
end;  

Function TSQLite3Cursor.Fetch : Boolean;

begin
  if (fstate=sqliteerrormax) then 
    fstate:=sqlite_row //first row;
  else if (fstate=sqlite_row) then 
    begin
    fstate:=sqlite3_step(fstatement);
    if (fstate<=sqliteerrormax) then 
      checkerror(sqlite3_reset(fstatement));  //right error returned??
    end;
  result:=(fstate=sqlite_row);
end;

{ TSQLite3Connection }

procedure TSQLite3Connection.LoadBlobIntoBuffer(FieldDef: TFieldDef;ABlobBuf: PBufBlobField; cursor: TSQLCursor; ATransaction : TSQLTransaction); 

var
 int1: integer;
 st: psqlite3_stmt;
 fnum: integer;

begin
  st:=TSQLite3Cursor(cursor).fstatement;
  fnum:= FieldDef.fieldno - 1;

  int1:= sqlite3_column_bytes(st,fnum);

  ReAllocMem(ABlobBuf^.BlobBuffer^.Buffer,int1);
  if int1 > 0 then
    move(sqlite3_column_text(st,fnum)^,ABlobBuf^.BlobBuffer^.Buffer^,int1);
  ABlobBuf^.BlobBuffer^.Size := int1;
end;

function TSQLite3Connection.AllocateTransactionHandle: TSQLHandle;
begin
 result:= tsqlhandle.create;
end;

function TSQLite3Connection.AllocateCursorHandle: TSQLCursor;

Var
  Res : TSQLite3Cursor;

begin
  Res:= TSQLite3Cursor.create;
  Res.fhandle:=self.fhandle;
  Result:=Res;
end;

procedure TSQLite3Connection.DeAllocateCursorHandle(var cursor: TSQLCursor);
begin
  freeandnil(cursor);
end;

procedure TSQLite3Connection.PrepareStatement(cursor: TSQLCursor;
               ATransaction: TSQLTransaction; buf: string; AParams: TParams);
begin
  TSQLite3Cursor(cursor).Prepare(Buf,AParams);
end;

procedure TSQLite3Connection.UnPrepareStatement(cursor: TSQLCursor);

begin
  TSQLite3Cursor(cursor).UnPrepare;
end;


Type
  TFieldMap = Record
    N : String;
    T : TFieldType;
  end;
  
Const
  FieldMapCount = 19;
  FieldMap : Array [1..FieldMapCount] of TFieldMap = (
   (n:'INT'; t: ftInteger),
   (n:'LARGEINT'; t:ftlargeInt),
   (n:'WORD'; t: ftWord),
   (n:'SMALLINT'; t: ftSmallint),
   (n:'BOOLEAN'; t: ftBoolean),
   (n:'REAL'; t: ftFloat),
   (n:'FLOAT'; t: ftFloat),
   (n:'DOUBLE'; t: ftFloat),
   (n:'TIMESTAMP'; t: ftDateTime),
   (n:'DATETIME'; t: ftDateTime), // MUST be before date
   (n:'DATE'; t: ftDate),
   (n:'TIME'; t: ftTime),
   (n:'CURRENCY'; t: ftCurrency),
   (n:'VARCHAR'; t: ftString),
   (n:'CHAR'; t: ftString),
   (n:'NUMERIC'; t: ftBCD),
   (n:'DECIMAL'; t: ftBCD),
   (n:'TEXT'; t: ftmemo),
   (n:'BLOB'; t: ftBlob)
{ Template:
  (n:''; t: ft)
}
  );

procedure TSQLite3Connection.AddFieldDefs(cursor: TSQLCursor;
               FieldDefs: TfieldDefs);
var
 i     : integer;
 FN,FD : string;
 ft1   : tfieldtype;
 size1 : word;
 ar1   : TStringArray;
 fi    : integer;
 st    : psqlite3_stmt;
 
begin
  st:=TSQLite3Cursor(cursor).fstatement;
  for i:= 0 to sqlite3_column_count(st) - 1 do 
    begin
    FN:=sqlite3_column_name(st,i);
    FD:=uppercase(sqlite3_column_decltype(st,i));
    ft1:= ftUnknown;
    size1:= 0;
    for fi := 1 to FieldMapCount do if pos(FieldMap[fi].N,FD)=1 then
      begin
      ft1:=FieldMap[fi].t;
      break;
      end;
    // Empty field types are allowed and used in calculated columns (aggregates)
    // and by pragma-statements
    if FD='' then ft1 := ftString;
    // handle some specials.
    size1:=0;
    case ft1 of
      ftString: begin
                fi:=pos('(',FD);
                if (fi>0) then
                  begin
                  System.Delete(FD,1,fi);
                  fi:=pos(')',FD);
                  size1:=StrToIntDef(trim(copy(FD,1,fi-1)),255);
                  if size1 > dsMaxStringSize then size1 := dsMaxStringSize;
                  end
                else size1 := 255;
                end;
      ftBCD:    begin
                fi:=pos(',',FD);
                if (fi>0) then
                  begin
                  System.Delete(FD,1,fi);
                  fi:=pos(')',FD);
                  size1:=StrToIntDef(trim(copy(FD,1,fi-1)),255);
                  end
                else size1 := 4;
                end;
      ftUnknown : DatabaseError('Unknown record type: '+FN);
    end; // Case
    tfielddef.create(fielddefs,FN,ft1,size1,false,i+1);
    end;
end;

procedure TSQLite3Connection.Execute(cursor: TSQLCursor; atransaction: tsqltransaction; AParams: TParams);
var
 SC : TSQLite3Cursor;
            
begin
  SC:=TSQLite3Cursor(cursor);
  If (AParams<>Nil) and (AParams.count > 0) then
    SC.BindParams(AParams);
  SC.Execute;    
end;

Function NextWord(Var S : ShortString; Sep : Char) : String;

Var
  P : Integer;

begin
  P:=Pos(Sep,S);
  If (P=0) then 
    P:=Length(S)+1;
  Result:=Copy(S,1,P-1);
  Delete(S,1,P);
end;

Function ParseSQLiteDate(S : ShortString) : TDateTime;

Var
  Year, Month, Day : Integer;

begin
 Result:=0;
 If TryStrToInt(NextWord(S,'-'),Year) then
   if TryStrToInt(NextWord(S,'-'),Month) then
     if TryStrToInt(NextWord(S,'-'),Day) then
        Result:=EncodeDate(Year,Month,Day);
end;

Function ParseSQLiteTime(S : ShortString) : TDateTime;

Var
  Hour, Min, Sec : Integer;

begin
  Result:=0;
  If TryStrToInt(NextWord(S,':'),Hour) then
    if TryStrToInt(NextWord(S,':'),Min) then
      if TryStrToInt(NextWord(S,':'),Sec) then
        Result:=EncodeTime(Hour,Min,Sec,0);
end;

Function ParseSQLiteDateTime(S : String) : TDateTime;

var
  P : Integer;
  DS,TS : ShortString;

begin
  DS:='';
  TS:='';
  P:=Pos(' ',S);
  If (P<>0) then
    begin
    DS:=Copy(S,1,P-1);
    TS:=S;
    Delete(TS,1,P);
    end
  else
    begin  
    If (Pos('-',S)<>0) then
      DS:=S
    else if (Pos(':',S)<>0) then
      TS:=S;
    end;
  Result:=ComposeDateTime(ParseSQLiteDate(DS),ParseSQLiteTime(TS));
end;
function TSQLite3Connection.LoadField(cursor : TSQLCursor;FieldDef : TfieldDef;buffer : pointer; out CreateBlob : boolean) : boolean;

var
 st1: TStorageType;
 fnum: integer;
 i: integer;
 i64: int64;
 int1,int2: integer;
 str1: string;
 ar1,ar2: TStringArray;
 st    : psqlite3_stmt;
 
begin
  st:=TSQLite3Cursor(cursor).fstatement;
  fnum:= FieldDef.fieldno - 1;
  st1:= TStorageType(sqlite3_column_type(st,fnum));
  CreateBlob:=false;
  result:= st1 <> stnull;
  if Not result then 
    Exit;
  case FieldDef.datatype of
    ftInteger  : pinteger(buffer)^  := sqlite3_column_int(st,fnum);
    ftSmallInt : psmallint(buffer)^ := sqlite3_column_int(st,fnum);
    ftWord     : pword(buffer)^     := sqlite3_column_int(st,fnum);
    ftBoolean  : pwordbool(buffer)^ := sqlite3_column_int(st,fnum)<>0;
    ftLargeInt,
    ftBCD      : PInt64(buffer)^:= sqlite3_column_int64(st,fnum);
    ftFloat,
    ftCurrency : pdouble(buffer)^:= sqlite3_column_double(st,fnum);
    ftDateTime,
    ftDate,
    ftTime:  if st1 = sttext then 
               begin
               setlength(str1,sqlite3_column_bytes(st,fnum));
               move(sqlite3_column_text(st,fnum)^,str1[1],length(str1));
               PDateTime(Buffer)^:=ParseSqliteDateTime(str1)
               end
             else
               Pdatetime(buffer)^:= sqlite3_column_double(st,fnum);
    ftString: begin
              int1:= sqlite3_column_bytes(st,fnum);
              if int1>FieldDef.Size then 
                int1:=FieldDef.Size;
              if int1 > 0 then 
                 move(sqlite3_column_text(st,fnum)^,buffer^,int1);
              end;
    ftMemo,
    ftBlob: CreateBlob:=True;
  else { Case }
   result:= false; // unknown
  end; { Case }
end;

function TSQLite3Connection.Fetch(cursor: TSQLCursor): boolean;

begin
  Result:=TSQLite3Cursor(cursor).Fetch;
end;

procedure TSQLite3Connection.FreeFldBuffers(cursor: TSQLCursor);
begin
 //dummy
end;

function TSQLite3Connection.GetTransactionHandle(trans: TSQLHandle): pointer;
begin
 result:= nil;
end;

function TSQLite3Connection.Commit(trans: TSQLHandle): boolean;
begin
  execsql('COMMIT');
  result:= true;
end;

function TSQLite3Connection.RollBack(trans: TSQLHandle): boolean;
begin
  execsql('ROLLBACK');
  result:= true;
end;

function TSQLite3Connection.StartdbTransaction(trans: TSQLHandle;
               aParams: string): boolean;
begin
  execsql('BEGIN');
  result:= true;
end;

procedure TSQLite3Connection.CommitRetaining(trans: TSQLHandle);
begin
  commit(trans);  
  execsql('BEGIN');
end;

procedure TSQLite3Connection.RollBackRetaining(trans: TSQLHandle);
begin
  rollback(trans);
  execsql('BEGIN');
end;

procedure TSQLite3Connection.DoInternalConnect;
var
  str1: string;
begin
  if Length(databasename)=0 then
    DatabaseError(SErrNoDatabaseName,self);
  initialisesqlite;
  str1:= databasename;
  checkerror(sqlite3_open(pchar(str1),@fhandle));
end;

procedure TSQLite3Connection.DoInternalDisconnect;

begin
  if fhandle <> nil then 
    begin
    checkerror(sqlite3_close(fhandle));
    fhandle:= nil;
    releasesqlite;
    end; 
end;

function TSQLite3Connection.GetHandle: pointer;
begin
  result:= fhandle;
end;

procedure TSQLite3Connection.checkerror(const aerror: integer);

Var
  S : String;

begin
 if (aerror<>sqlite_ok) then 
   begin
   S:=strpas(sqlite3_errmsg(fhandle));
   DatabaseError(S,Self);
   end;
end;

procedure TSQLite3Connection.execsql(const asql: string);
var
 err  : pchar;
 str1 : string;
 res  : integer;
begin
 err:= nil;
 Res := sqlite3_exec(fhandle,pchar(asql),nil,nil,@err);
 if err <> nil then 
   begin
   str1:= strpas(err);
   sqlite3_free(err);
   end;
 if (res<>sqlite_ok) then 
   databaseerror(str1);
end;

function execcallback(adata: pointer; ncols: longint; //adata = PStringArray
                avalues: PPchar; anames: PPchar):longint; cdecl;
var
  P : PStringArray;
  i : integer;
  
begin
  P:=PStringArray(adata); 
  SetLength(P^,ncols);
  for i:= 0 to ncols - 1 do 
    P^[i]:= strPas(avalues[i]);
  result:= 0;
end;

function TSQLite3Connection.stringquery(const asql: string): TStringArray;
begin
  SetLength(result,0);
  CheckError(sqlite3_exec(fhandle,pchar(asql),@execcallback,@result,nil));
end;

function execscallback(adata: pointer; ncols: longint; //adata = PArrayStringArray
                avalues: PPchar; anames: PPchar):longint; cdecl;
var
 I,N : integer;
 PP : PArrayStringArray;
 p  : PStringArray;
 
begin
 PP:=PArrayStringArray(adata);
 N:=high(PP^); // Length-1;
 setlength(PP^,N+2); // increase with 1;
 p:= @(PP^[N]); // newly added array, fill with data.
 setlength(p^,ncols); 
 for i:= 0 to ncols - 1 do 
   p^[i]:= strPas(avalues[i]);
 result:= 0;
end;

function TSQLite3Connection.stringsquery(const asql: string): TArrayStringArray;
begin
  SetLength(result,0);
  checkerror(sqlite3_exec(fhandle,pchar(asql),@execscallback,@result,nil));
end;

function TSQLite3Connection.getprimarykeyfield(const atablename: string;
                                const acursor: tsqlcursor): string;
var
  int1,int2: integer;
  ar1: TArrayStringArray;
  str1: string;
  
begin
  result:= '';
  if atablename <> '' then 
    begin
    ar1:= stringsquery('PRAGMA table_info('+atablename+');');
    for int1:= 0 to high(ar1) do 
      begin
      if (high(ar1[int1]) >= 5) and (ar1[int1][5] <> '0') then 
        begin
        result:= ar1[int1][1];
        break;
        end;
      end;
    end;
end;

function TSQLite3Connection.RowsAffected(cursor: TSQLCursor): TRowsCount;
begin
  if assigned(cursor) then
    Result := (cursor as TSQLite3Cursor).RowsAffected
  else
    Result := -1;
end;

function TSQLite3Connection.GetSchemaInfoSQL(SchemaType: TSchemaType;
  SchemaObjectName, SchemaPattern: string): string;
  
begin
  case SchemaType of
    stTables     : result := 'select name as table_name from sqlite_master where type = ''table''';
    stColumns    : result := 'pragma table_info(''' + (SchemaObjectName) + ''')';
  else
    DatabaseError(SMetadataUnavailable)
  end; {case}
end;

function TSQLite3Connection.StrToStatementType(s: string): TStatementType;
begin
  S:=Lowercase(s);
  if s = 'pragma' then exit(stSelect);
  result := inherited StrToStatementType(s);
end;

procedure TSQLite3Connection.UpdateIndexDefs(var IndexDefs: TIndexDefs;
                              const TableName: string);
var
  str1: string;
  
begin
  str1:= getprimarykeyfield(tablename,nil);
  if str1 <> '' then 
    begin
    indexdefs.add('$PRIMARY_KEY$',str1,[ixPrimary,ixUnique]);
    end;
end;
{
procedure TSQLite3Connection.UpdateIndexDefs(var IndexDefs: TIndexDefs;
                              const TableName: string);
var
 int1,int2: integer;
 ar1: TArrayStringArray;
 str1: string;
begin
 ar1:= stringsquery('PRAGMA table_info('+tablename+');');
 for int1:= 0 to high(ar1) do begin
  if (high(ar1[int1]) >= 5) and (ar1[int1][5] <> '0') then begin
   indexdefs.add('$PRIMARY_KEY$',ar1[int1][1],[ixPrimary,ixUnique]);
   break;
  end;
 end;
end;
}

function TSQLite3Connection.getinsertid: int64;
begin
 result:= sqlite3_last_insert_rowid(fhandle);
end;

procedure TSQLite3Connection.GetFieldNames(const TableName: string;
  List: TStrings);
begin
  GetDBInfo(stColumns,TableName,'name',List);
end;

procedure TSQLite3Connection.setoptions(const avalue: tsqliteoptions);
begin
 if avalue <> foptions then 
   begin
   checkdisconnected;
   foptions:= avalue;
   end;
end;

end.