跨程序实现数据传递之FileMapping实现

一、传递数据结构定义及公共单元代码:

需要引入单元:winapi.windows;

1、声明部分

//用户库及主程序间数据共享相关
TAuthOnlineInfo = record
  IsDLL: Boolean;
  IsOnline: Boolean;
  IsAuth: Boolean;
  IsToDB: Boolean;
  CurDBID: Integer;
  UserName: string[255];
end;
PAuthOnlineInfo = ^TAuthOnlineInfo;
TAuthOnlineHelp = class
private
  const KeyName = ‘{89B70110-BC0A-426F-B097-3FC0271744AE}‘;

  class var FMapFile: THandle;
  class var FBuf: Pointer;
  class var FExist: Boolean;

  class function IsNT: Boolean;
public
  class function Exist: Boolean;
  //创建映射
  class function CreateMap(AInfo: PAuthOnlineInfo): Boolean;
  //更新映射
  class function UpdateMap(AInfo: PAuthOnlineInfo): Boolean;
  //关闭映射
  class procedure CloseMap;
  //获取映射数据
  class function GetAuthOnlineInfo(AInfo: PAuthOnlineInfo): Boolean;
end;

2、实现部分

{ TAuthOnlineHelp }

class procedure TAuthOnlineHelp.CloseMap;
begin
  if FBuf <> nil then
    UnMapViewOfFile(FBuf);
  if FMapFile <> 0 then
    CloseHandle(FMapFile);
  FBuf := nil;
  FMapFile := 0;
end;

class function TAuthOnlineHelp.CreateMap(AInfo: PAuthOnlineInfo): Boolean;
var
  SecurityDescriptor: TSecurityDescriptor;
  SecurityAttr: TSecurityAttributes;
begin
  //需要加安全设置,才能跨用户进程访问
  if IsNT then
  begin
    SecurityAttr.nLength := SizeOf(SECURITY_ATTRIBUTES);
    SecurityAttr.bInheritHandle := True;
    SecurityAttr.lpSecurityDescriptor := @SecurityDescriptor;

    if not InitializeSecurityDescriptor(@SecurityDescriptor, 1) then
      raise Exception.CreateFmt(‘初始化安全设置失败(%d)‘, [GetLastError]);
    if not SetSecurityDescriptorDacl(@SecurityDescriptor, TRUE, nil, FALSE) then
      raise Exception.CreateFmt(‘安全设置错误(%d)‘, [GetLastError]);
    if not SetKernelObjectSecurity(GetCurrentProcess, DACL_SECURITY_INFORMATION,
      @SecurityDescriptor) then
      raise Exception.CreateFmt(‘安全设置失败(%d)‘, [GetLastError]);

    FMapFile := CreateFileMapping($FFFFFFFF, @SecurityAttr, PAGE_READWRITE,
      0, SizeOf(TAuthOnlineInfo), PChar(KeyName));
  end
  else
    FMapFile := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE,
      0, SizeOf(TAuthOnlineInfo), PChar(KeyName));
  if (FMapFile = 0) or (GetLastError() = ERROR_ALREADY_EXISTS) then
  begin
    Result := False;
    Exit;
  end
  else
    Result := True;
  FBuf := MapViewOfFile(FMapFile, FILE_MAP_ALL_ACCESS, 0, 0, 0);
  if (FBuf = nil) then
  begin

    raise Exception.CreateFmt(‘映射内存空间失败 (%d).‘, [GetLastError]);
      CloseHandle(FMapFile);

    Result := False;
    Exit;
  end
  else if AInfo <> nil then
   CopyMemory(FBuf, AInfo, SizeOf(TAuthOnlineInfo));
  FExist := True;
end;

class function TAuthOnlineHelp.Exist: Boolean;
begin
  Result := FExist;
end;

class function TAuthOnlineHelp.GetAuthOnlineInfo(AInfo: PAuthOnlineInfo): Boolean;
var
  hMapFile: THandle;
  pBuf: Pointer;
begin
  Result := False;
  if (AInfo= nil) then Exit;

  hMapFile := OpenFileMapping(FILE_MAP_READ, FALSE, PChar(KeyName));
  if hMapFile = 0 then
  begin
    Result := False;
    Exit;
  end;

  pBuf := MapViewOfFile(hMapFile, FILE_MAP_READ, 0, 0, SizeOf(TAuthOnlineInfo));
  if (pBuf = nil) then
  begin
    CloseHandle(hMapFile);
    Result := False;
    Exit;
  end;
  CopyMemory(AInfo, pBuf, SizeOf(TAuthOnlineInfo));
  UnmapViewOfFile(pBuf);
  CloseHandle(hMapFile);

  Result := True;
end;

class function TAuthOnlineHelp.IsNT: Boolean;
var
  OS: TOSVERSIONINFO;
begin
  OS.dwOSVersionInfoSize := SizeOf(TOSVERSIONINFO);
  GetVersionEx(OS);
  Result := (OS.dwMajorVersion >= 5) or (OS.dwPlatformId = VER_PLATFORM_WIN32_NT);
end;

class function TAuthOnlineHelp.UpdateMap(AInfo: PAuthOnlineInfo): Boolean;
begin
  Result := False;
  if (AInfo= nil) then Exit;

  if FMapFile = 0 then
    Exit
  else
  begin
    CopyMemory(FBuf, AInfo, SizeOf(TAuthOnlineInfo));
    Result := True;
  end;
end;

 

二、创建映射的进程代码 

New(pInfo);  //pInfo 类型PAuthOnlineInfo 
pInfo.IsDLL := False;
pInfo.CurDBID := ASheet.App.BaseData.CurUserDBID;
if TAuthOnlineHelp.Exist then
  TAuthOnlineHelp.UpdateMap(pInfo)
else
  TAuthOnlineHelp.CreateMap(pInfo);
Dispose(pInfo);
ShellExecute(0, ‘Open‘, PWideChar(sFileName), nil, nil, SW_SHOWMAXIMIZED);  //sFileName是第二个进程名称

 

三、读取映射文件的进程代码

New(pInfo);   //pInfo 类型PAuthOnlineInfo 
TAuthOnlineHelp.GetAuthOnlineInfo(pInfo);

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