MORMOT的数据序列

mormot服务器回复客户端通过Ctxt.OutContent属性。

此属性的类型是：SockString。   // property OutContent: SockString read fOutContent write fOutContent ;

继续跟代码，发现SockString是RawByteString类型。

type{$ifdef UNICODE}  /// define the fastest Unicode string type of the compiler  SynUnicode = UnicodeString;  /// define a raw 8-bit storage string type, used for data buffer management  SockString = type RawByteString;{$else}  /// define the fastest 16-bit Unicode string type of the compiler  SynUnicode = WideString;  {$ifdef HASCODEPAGE} // FPC may expect a CP, e.g. to compare two string constants  SockString = type RawByteString;  {$else}  /// define a 8-bit raw storage string type, used for data buffer management  SockString = type AnsiString;  {$endif}{$endif}

　继续跟代码，发现RawByteString是AnsiString类型。从下面的代码可以看出，

RawByteString是跨平台的，针对不同的平台有不同的编译开关。这也是为什么要封装一个RawByteString类型。

{
    $IFDEF NEXTGEN}  UTF8String = type _AnsiString(65001);  RawByteString = type _AnsiString($ffff);  {
    $NODEFINE UTF8String}  {
    $NODEFINE RawByteString}{
    $ELSEIF Defined(LINUX64) or Defined(OSX64)}  UTF8String = type AnsiString(65001);  RawByteString = type AnsiString($ffff);  {
    $NODEFINE UTF8String}  {
    $NODEFINE RawByteString}{
    $ELSE}  UTF8String = type AnsiString(65001);  RawByteString = type AnsiString($ffff);{
    $ENDIF}

mormot在SynCommons.pas单元定义了一些RawByteString和其它数据类型相互转换的公共函数，一起来看看。

stream和RawByteString相互转换函数：

function StreamToRawByteString(aStream: TStream): RawByteString;var current, size: Int64;begin  result := '';  if aStream=nil then    exit;  current := aStream.Position;  if (current=0) and aStream.InheritsFrom(TRawByteStringStream) then begin    result := TRawByteStringStream(aStream).DataString; // fast COW    exit;  end;  size := aStream.Size-current;  if (size=0) or (size>maxInt) then    exit;  SetLength(result,size);  aStream.Read(pointer(result)^,size);  aStream.Position := current;end;

　　

function RawByteStringToStream(const aString: RawByteString): TStream;begin  result := TRawByteStringStream.Create(aString);end;

　　bytes和RawByteString相互转换函数：

procedure BytesToRawByteString(const bytes: TBytes; out buf: RawByteString);begin  SetString(buf,PAnsiChar(pointer(bytes)),Length(bytes));end;

　　

procedure RawByteStringToBytes(const buf: RawByteString; out bytes: TBytes);var L: Integer;begin  L := Length(buf);  if L<>0 then begin    SetLength(bytes,L);    MoveFast(pointer(buf)^,pointer(bytes)^,L);  end;end;

　　RawByteString和Variant相互转换函数：

procedure RawByteStringToVariant(const Data: RawByteString; var Value: variant);begin  with TVarData(Value) do begin    {$ifndef FPC}if VType and VTYPE_STATIC<>0 then{$endif}      VarClear(Value);    if Data='' then      VType := varNull else begin      VType := varString;      VAny := nil; // avoid GPF below when assigning a string variable to VAny      RawByteString(VAny) := Data;    end;  end;end;

　　

procedure VariantToRawByteString(const Value: variant; var Dest: RawByteString);begin  case TVarData(Value).VType of  varEmpty, varNull:    Dest := '';  varString:    Dest := RawByteString(TVarData(Value).VAny);  else // not from RawByteStringToVariant() -> conversion to string    Dest := {$ifdef UNICODE}RawByteString{$else}string{$endif}(Value);  end;end;

　　stream,ansistring,variant基本上代表了常用的数据格式。