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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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35
packages/fcl-db/src/base/bufdataset.pas
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@ -384,6 +384,21 @@ type
{ TFpcBinaryDatapacketReader } { 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) TFpcBinaryDatapacketReader = class(TDataPacketReader)
private private
const const
@ -392,9 +407,11 @@ type
StringFieldTypes = [ftString,ftFixedChar,ftWideString,ftFixedWideChar]; StringFieldTypes = [ftString,ftFixedChar,ftWideString,ftFixedWideChar];
BlobFieldTypes = [ftBlob,ftMemo,ftWideMemo]; BlobFieldTypes = [ftBlob,ftMemo,ftWideMemo];
VarLenFieldTypes = StringFieldTypes + BlobFieldTypes + [ftBytes,ftVarBytes]; VarLenFieldTypes = StringFieldTypes + BlobFieldTypes + [ftBytes,ftVarBytes];
protected
var var
FVersion: byte; FVersion: byte;
public public
constructor Create(AStream : TStream); override;
procedure LoadFieldDefs(AFieldDefs : TFieldDefs; var AnAutoIncValue : integer); override; procedure LoadFieldDefs(AFieldDefs : TFieldDefs; var AnAutoIncValue : integer); override;
procedure StoreFieldDefs(AFieldDefs : TFieldDefs; AnAutoIncValue : integer); override; procedure StoreFieldDefs(AFieldDefs : TFieldDefs; AnAutoIncValue : integer); override;
procedure InitLoadRecords; override; procedure InitLoadRecords; override;
@ -3515,6 +3532,12 @@ end;
{ TFpcBinaryDatapacketReader } { TFpcBinaryDatapacketReader }
constructor TFpcBinaryDatapacketReader.Create(AStream: TStream);
begin
inherited;
FVersion := 20; // default version 2.0
end;
procedure TFpcBinaryDatapacketReader.LoadFieldDefs(AFieldDefs: TFieldDefs; var AnAutoIncValue: integer); procedure TFpcBinaryDatapacketReader.LoadFieldDefs(AFieldDefs: TFieldDefs; var AnAutoIncValue: integer);
var FldCount : word; var FldCount : word;
@ -3555,7 +3578,7 @@ procedure TFpcBinaryDatapacketReader.StoreFieldDefs(AFieldDefs: TFieldDefs; AnAu
var i : integer; var i : integer;
begin begin
Stream.Write(FpcBinaryIdent2[1], length(FpcBinaryIdent2)); Stream.Write(FpcBinaryIdent2[1], length(FpcBinaryIdent2));
Stream.WriteByte(20); // version 2.0 Stream.WriteByte(FVersion);
Stream.WriteWord(AFieldDefs.Count); Stream.WriteWord(AFieldDefs.Count);
for i := 0 to AFieldDefs.Count -1 do with AFieldDefs[i] do for i := 0 to AFieldDefs.Count -1 do with AFieldDefs[i] do
@ -3608,11 +3631,11 @@ var
L: cardinal; L: cardinal;
B: TBytes; B: TBytes;
begin begin
with ADataset do
case FVersion of case FVersion of
10: 10:
Stream.ReadBuffer(ADataset.GetCurrentBuffer^, ADataset.FRecordSize); // Ugly because private members of ADataset are used... Stream.ReadBuffer(GetCurrentBuffer^, FRecordSize); // Ugly because private members of ADataset are used...
20: 20:
with ADataset do
for i:=0 to FieldDefs.Count-1 do for i:=0 to FieldDefs.Count-1 do
begin begin
AField := Fields.FieldByNumber(FieldDefs[i].FieldNo); AField := Fields.FieldByNumber(FieldDefs[i].FieldNo);
@ -3652,8 +3675,11 @@ begin
Stream.WriteBuffer(AUpdOrder,sizeof(integer)); Stream.WriteBuffer(AUpdOrder,sizeof(integer));
// Record data // Record data
// Old 1.0 version: Stream.WriteBuffer(ADataset.GetCurrentBuffer^, ADataset.FRecordSize);
with ADataset do with ADataset do
case FVersion of
10:
Stream.WriteBuffer(GetCurrentBuffer^, FRecordSize); // Old 1.0 version
20:
for i:=0 to FieldDefs.Count-1 do for i:=0 to FieldDefs.Count-1 do
begin begin
AField := Fields.FieldByNumber(FieldDefs[i].FieldNo); AField := Fields.FieldByNumber(FieldDefs[i].FieldNo);
@ -3671,6 +3697,7 @@ begin
end; end;
end; end;
end; end;
end;
procedure TFpcBinaryDatapacketReader.FinalizeStoreRecords; procedure TFpcBinaryDatapacketReader.FinalizeStoreRecords;
begin begin