集成桌面搜索，模拟器#
This is a revised version of an earlier blog at http://blog.joycode.com/jiangsheng/archive/2005/07/19/59725.aspx, published July 19, 2005. The source code is available at jiangsheng/Samples
微软的桌面搜索API推出也有一段时间了，但是网上可以找到的相关技术资料还不多。官方的资料在https://web.archive.org/web/20051030062212/http://addins.msn.com/devguide.aspx可以看到，而且网页上有SDK和一个C#的示例供下载。
The beta version of Windows Desktop Search (WDS) is released for a while. The SDK with a sample in C# is available for download at http://addins.msn.com/devguide.aspx. And using it in Visual C applications is quite easy, too.
First, you need to import ADO, since WDS uses ADO to return search results
#import "c:\Program Files\Common Files\system\ado\Msado15.dll" rename("EOF","adoEOF") rename("DataTypeEnum","adoDataTypeEnum")
using namespace ADODB;
Then import the wdsQuery.tlb file, which can be found in the SDK
#import "wdsQuery.tlb" rename("EOF","adoEOF") rename("DataTypeEnum","adoDataTypeEnum")
using namespace WDSQuery;
You need a CLSID to create the search engine object. The CLSID of the WDS object is not too hard to find in the wdsQuery.idl, which is also part of the WDS SDK.
DEFINE_GUID(CLSID_SearchDesktop,0x1AD68C99,0x00FB,0x416d,0x80,0x4B,0xC3,0x8D,0xEE,0x75,0xD5,0x5E);
使用搜索API非常的简单，首先创建一个桌面搜索对象
Now you can create the object like this
ISearchDesktopPtr m_pSearchDesktop;
BOOL CWDSSampleView::PreCreateWindow(CREATESTRUCT& cs)
{
// TODO: Modify the Window class or styles here by modifying
// the CREATESTRUCT cs
if(m_pSearchDesktop.CreateInstance(CLSID_SearchDesktop))
{
AfxMessageBox(IDS_FAILED_TO_CREATE_SEARCH_ENGINE);
return FALSE;
}
之后就可以开始执行搜索了。桌面搜索对象有两个方法，ExecuteSQLQuery和ExecuteQuery，都返回一个ADO记录集对象。ExecuteQuery是对用户比较友好的版本，参数虽然比较多，但是不需要自己构建SQL；而ExecuteSQLQuery是底层版本，只有一个参数——需要自己构造的SQL。相信我，你不会渴望自己来创建SQL的。传递给ExecuteQuery的参数就已经够长的了。字符串表中IDS_COLUMNS_GENERAL的内容是：
The object has two search methods that return an ADO recordset. The ExecuteSQLQuery method is the friendly one, takes a string and return the search result. The ExecuteSQLQuery method, on the contrary, accept a SQL statement. Believe me, you won’t eager to construct the SQL by yourself. The parameter list of the ExecuteSQLQuery method is long enough. Here are the columns I choose:
DocTitle,DocFormat,Url,DocAuthor,PrimaryDate,FileName, FileExt,IsAttachment,Characterization,Rank,PerceivedType, HasAttach,DocTitlePrefix,FileExtDesc,DisplayFolder, DocKeywords,DocComments,ConversationID,Size, Create,Write
void CWDSSampleView::Search(LPCTSTR lpszQuery,LPCTSTR lpszSort)
{
CString strQuery(lpszQuery);if(strQuery.IsEmpty())return;
CString strSort(lpszSort);
USES_CONVERSION;
HRESULT hr=S_OK;
GetListCtrl().SetItemCount(0);
ClearCache();
try{
CString strColumns;
VERIFY(strColumns.LoadString(IDS_COLUMNS_GENERAL));
if(strSort.IsEmpty())
m_pRecordset=m_pSearchDesktop->ExecuteQuery(T2OLE(strQuery),
T2OLE(strColumns),NULL,NULL);
else
m_pRecordset=m_pSearchDesktop->ExecuteQuery(T2OLE(strQuery),
T2OLE(strColumns),T2OLE(strSort),NULL);
int nItemCount=m_pRecordset->GetRecordCount();
GetListCtrl().SetItemCount(nItemCount);
}
catch(_com_error&e)
{
//……
}
}
但是，访问返回的记录集的速度比访问数据库要慢。我不得不用虚列表和缓存来提高性能。在搜索结果很多（例如关键字选择”Microsoft”）时程序有假死现象——当然也不排除我选择的字段过多的原因。
See, to increase performance, I used a cache and a virtual list control. But the application is still a little slow, if the search result list is too large. A better way to return the result set is to reduce date transfer. The search should only return the primary key column and the sorting columns, and when an item is about to be displayed, search again to get the information of this item.
最近在写一个14位CPU的模拟器，CPU指令长度是固定的——13字节，十分的不吉利^_^b，而且CPU指令集中一些特定指令会根据上下文判断是否跳过下一个指令。但是在Intel系统上没有这样的指令，而且指令长度是可变的，所以无法知道下一个指令的长度来跳过它。我现在是在内存中设置一个标志，在执行每个指令之前检查这个标志来判断前一个指令是否指明跳过当前指令——低效，但是可以正常工作。