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fcl-db: bufdataset: make TFpcBinaryDatapacketReader more flexible hence descendant can override version preset in constructor and write in old format.

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git-svn-id: trunk@25508 -
This commit is contained in:
lacak 2013-09-17 12:43:45 +00:00
parent 129fddf800
commit baa700925c
1 changed files with 52 additions and 25 deletions
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77
packages/fcl-db/src/base/bufdataset.pas
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@ -384,6 +384,21 @@ type
{ TFpcBinaryDatapacketReader }
{ Format description:
Header:
Identification: 13 bytes: 'BinBufDataSet'
Version: 1 byte
FieldDefs:
Number of Fields: 2 bytes
For each FieldDef: Name, DisplayName, Size: 2 bytes, DataType: 2 bytes, ReadOnlyAttr: 1 byte
AutoInc Value: 4 bytes
Records:
Record header: each record begins with $fe: 1 byte
row state: 1 byte
update order: 4 bytes
Record data:
}
TFpcBinaryDatapacketReader = class(TDataPacketReader)
private
const
@ -392,9 +407,11 @@ type
StringFieldTypes = [ftString,ftFixedChar,ftWideString,ftFixedWideChar];
BlobFieldTypes = [ftBlob,ftMemo,ftWideMemo];
VarLenFieldTypes = StringFieldTypes + BlobFieldTypes + [ftBytes,ftVarBytes];
protected
var
FVersion: byte;
public
constructor Create(AStream : TStream); override;
procedure LoadFieldDefs(AFieldDefs : TFieldDefs; var AnAutoIncValue : integer); override;
procedure StoreFieldDefs(AFieldDefs : TFieldDefs; AnAutoIncValue : integer); override;
procedure InitLoadRecords; override;
@ -2339,7 +2356,7 @@ begin
SetFieldIsNull(NullMask, blobbuf.BlobBuffer^.FieldNo-1)
else
unSetFieldIsNull(NullMask, blobbuf.BlobBuffer^.FieldNo-1);
blobbuf.BlobBuffer^.FieldNo := -1;
end;
@ -3515,6 +3532,12 @@ end;
{ TFpcBinaryDatapacketReader }
constructor TFpcBinaryDatapacketReader.Create(AStream: TStream);
begin
inherited;
FVersion := 20; // default version 2.0
end;
procedure TFpcBinaryDatapacketReader.LoadFieldDefs(AFieldDefs: TFieldDefs; var AnAutoIncValue: integer);
var FldCount : word;
@ -3555,7 +3578,7 @@ procedure TFpcBinaryDatapacketReader.StoreFieldDefs(AFieldDefs: TFieldDefs; AnAu
var i : integer;
begin
Stream.Write(FpcBinaryIdent2[1], length(FpcBinaryIdent2));
Stream.WriteByte(20); // version 2.0
Stream.WriteByte(FVersion);
Stream.WriteWord(AFieldDefs.Count);
for i := 0 to AFieldDefs.Count -1 do with AFieldDefs[i] do
@ -3608,11 +3631,11 @@ var
L: cardinal;
B: TBytes;
begin
case FVersion of
10:
Stream.ReadBuffer(ADataset.GetCurrentBuffer^, ADataset.FRecordSize); // Ugly because private members of ADataset are used...
20:
with ADataset do
with ADataset do
case FVersion of
10:
Stream.ReadBuffer(GetCurrentBuffer^, FRecordSize); // Ugly because private members of ADataset are used...
20:
for i:=0 to FieldDefs.Count-1 do
begin
AField := Fields.FieldByNumber(FieldDefs[i].FieldNo);
@ -3634,7 +3657,7 @@ begin
AField.SetData(@B[0], False); // set it to the FilterBuffer
end;
end;
end;
end;
end;
procedure TFpcBinaryDatapacketReader.StoreRecord(ADataset: TCustomBufDataset;
@ -3652,24 +3675,28 @@ begin
Stream.WriteBuffer(AUpdOrder,sizeof(integer));
// Record data
// Old 1.0 version: Stream.WriteBuffer(ADataset.GetCurrentBuffer^, ADataset.FRecordSize);
with ADataset do
for i:=0 to FieldDefs.Count-1 do
begin
AField := Fields.FieldByNumber(FieldDefs[i].FieldNo);
if AField=nil then continue;
if AField.DataType in StringFieldTypes then
Stream.WriteAnsiString(AField.AsString)
else
begin
B := AField.AsBytes;
L := length(B);
if AField.DataType in VarLenFieldTypes then
Stream.WriteDWord(L);
if L > 0 then
Stream.WriteBuffer(B[0], L);
end;
end;
case FVersion of
10:
Stream.WriteBuffer(GetCurrentBuffer^, FRecordSize); // Old 1.0 version
20:
for i:=0 to FieldDefs.Count-1 do
begin
AField := Fields.FieldByNumber(FieldDefs[i].FieldNo);
if AField=nil then continue;
if AField.DataType in StringFieldTypes then
Stream.WriteAnsiString(AField.AsString)
else
begin
B := AField.AsBytes;
L := length(B);
if AField.DataType in VarLenFieldTypes then
Stream.WriteDWord(L);
if L > 0 then
Stream.WriteBuffer(B[0], L);
end;
end;
end;
end;
procedure TFpcBinaryDatapacketReader.FinalizeStoreRecords;