C++ TFileName::SetLength方法代码示例

void CRefTestAgentImportFile::DumpMetaData(const CMetaDataArray& aMetaDataArray)
	{
	_LIT(KMetaDataLogFile, "c:\\logs\\rta\\metadata");
	_LIT(KExt, ".log");
	
	TInt id(0);
	TInt err(KErrNone);
	TFileName filename;
	RFile file;
	do	{
		filename.SetLength(0);
		filename.Append(KMetaDataLogFile);
		filename.AppendNum(++id);
		filename.Append(KExt);
		err = file.Create(iFs,filename,EFileWrite);
		} while(err == KErrAlreadyExists);

	if(err == KErrNone)
		{
		for(TInt i=0;i<aMetaDataArray.Count();i++)
			{
			file.Write(aMetaDataArray[i].Field8());
			file.Write(_L8(" "));
			file.Write(aMetaDataArray[i].Data8());
			file.Write(_L8("\r\n"));
			}
		file.Close();
		}
	}

LOCAL_C void doExampleL()
{
    // Define descriptor constants using the _LIT macro
    _LIT(KMessage1,"Default path for fsSession is %S\n");
    _LIT(KMessage2,"Session path for fsSession is now %S\n");
    _LIT(KMessage3,"Session path for fsSession2 is %S\n");
    _LIT(KTestDir,"f32test\\");

    // Open file server session
    User::LeaveIfError(fsSession.Connect());

    // Get the default session path, and display it.
    // It should be the private path for this (process)
    // i.e. c:\private\0fffff04.
    TFileName path;
    User::LeaveIfError(fsSession.SessionPath(path));
    console->Printf(KMessage1,&path);

    // Create a directory within the default session path.
    // and then set the default path to the full directory.
    //
    // Steps.
    //
    // 1  Create the private path - it is not automatically created by Symbian OS.
    // 2. Get the name of the private path
    // 3. Create the new directory level f32test\ within the private path
    // 4. Set the session path to \private\0fffff04\f32test.
    User::LeaveIfError(fsSession.CreatePrivatePath(EDriveC)); // <--- 1.
    fsSession.PrivatePath(path);   // <------------------------------ 2.
    path.Append(KTestDir);
    User::LeaveIfError(fsSession.MkDir(path));// <------------------- 3.
    User::LeaveIfError(fsSession.SetSessionPath(path)); // <--------- 4.

    // Retrieve the session path to make sure that the system
    // agrees with what we believe is the new session path.
    // Clear the path descriptor; this is NOT necessary, but just
    // shows that we are not cheating !
    path.SetLength(0);
    User::LeaveIfError(fsSession.SessionPath(path));
    console->Printf(KMessage2,&path);

    // Make another connection to the file server and show
    // its default session path.It should be the original
    // private path for this (process) i.e. c:\private\0fffff04.
    RFs fsSession2;
    User::LeaveIfError(fsSession2.Connect());
    fsSession2.SessionPath(path);
    console->Printf(KMessage3,&path);

    // Remove the \f32test\ directory
    fsSession.PrivatePath(path);
    path.Append(KTestDir);
    User::LeaveIfError(fsSession.RmDir(path));

    // Close these two sessions with the file server.
    fsSession2.Close();
    fsSession.Close();
}

//static
QFileSystemEntry QFileSystemEngine::currentPath()
{
    TFileName fn;
    QFileSystemEntry ret;
    TInt r = qt_s60GetRFs().SessionPath(fn);
    if(r == KErrNone) {
        //remove terminating slash from non root paths (session path is clean, absolute and always ends in a \)
        if(fn.Length() > 3 && fn[fn.Length() - 1] == '\\')
            fn.SetLength(fn.Length() - 1);
        ret = QFileSystemEntry(qt_TDesC2QString(fn), QFileSystemEntry::FromNativePath());
    }
    return ret;
}

TInt CWidgetRegistrySTIF::ClientSessionGetWidgetPathL( TTestResult& aResult )
    {
    aResult.SetResult( KErrGeneral, KFailed );
    RWidgetRegistryClientSession* registryClient;
    registryClient = new (ELeave) RWidgetRegistryClientSession;
    CleanupStack::PushL( registryClient );
    TInt error = registryClient->Connect();
    if ( KErrNone == error )
        {
        TFileName fn;
        fn.SetLength( 0 );
        registryClient->GetWidgetPath( iValidUid, fn );
        if ( 0 < fn.Length() )
            {
            aResult.SetResult( KErrNone, KPassed );
            }
        registryClient->Disconnect();
        }
    CleanupStack::PopAndDestroy( registryClient );
    return KErrNone;
    }

void __fastcall TCDirectoryOutline::SetDirectory(const TFileName NewDir)
{
    if (NewDir.Length() > 0) {
        TFileName Path = ForceCase(ExpandFileName(NewDir));
        int n = Path.Length();

        if (n > 3 && Path.IsPathDelimiter(n))
            Path.SetLength(n - 1);

        if (Path != FDirectory) {
            FDirectory = Path;
            chdir(FDirectory.c_str());

            if (!SameLetter(Path[1], Drive))
                Drive = Path[1];
            else {
                WalkTree(Path);
                Change();
            }
        }
    }
}

void
CNfsAppUi::ConstructL()
{
  TFileName fnb;
  fnb.Copy(Application()->AppFullName());
  int l;
  for(l = fnb.Length()-1; l; l--)
    if(fnb[l] == '\\')
      break;
  fnb.SetLength(l+1);
  fnb.Append(_L("nfsclient.exe"));
#if !defined(__int64)	// Old SDK
  EikDll::StartExeL(fnb);
#else
 RProcess pr;
 if(pr.Create(fnb,fnb) == KErrNone)
   {
     pr.Resume();
     pr.Close();
   }
#endif

  User::Exit(0);
}

TInt CMusicPlayerImgEngine::GetAlbumArtFilename(const CMetadata &aMetadata, const TSize &aSize, TFileName &aCoverFilename, CImageDecoder **aDecoder) 
{
	/* Function returns KErrNotFound if we find nothing, it returns 0 if we find a file, and it returns 1 if the elemnt is in cache
	 * In aCacheIndex returns the cache index, if found there, or -1. If found in cache, the cache is updated.
	 * If NOT found in cache, aCoverFilename contains the cover filename. If aMetadata.iCover is valid (non-NULL)
	 * then the aCoverFilename is non-existent, e.g. e:\\Music\\Something\\Else.mp3_360.jpg The purpose in this case
	 * would be to identify the image in the cache.
	 * 
	 * The algorithm for finding the album art:
	 * 1. Check if there is aMetadata.iCover. If it does, check the cache, update aCoverFilename, return.
	 * 2. Check for KAlbumCoverNameGeneric (cover.jpg) in song's folder.
	 * 3. Check for KAlbumCoverNameGeneric2 (folder.jpg) in song's folder.
	 * 4. If aMetadata artist and album are non-NULL, check the Source/__Covers/Artist-Album.jpg
	 * 5. If enabled in Preferences, create a "hint" Source/__Covers/Artist-Album.hint having 0 bytes
	 * 6. If here, return KErrNotFound
	 */
	
	aMetadata.iFileDirEntry->GetFullPath(aCoverFilename,ETrue);
	LOG(ELogGeneral,1,"GetAlbumArtFilename++ (%S), iCover=%x",&aCoverFilename,aMetadata.iCover);

	TInt r,err;
	TEntry entry;
	
	*aDecoder=NULL;
	if(aMetadata.iCover) {
		aMetadata.iFileDirEntry->GetFullPath(aCoverFilename);
		//check if we have this in cache
		if(IsInCache(aCoverFilename,aSize)) {
			LOG(ELogGeneral,-1,"GetAlbumArtFilename-- (we have embedded cover, in cache)");
			return 1; 
		}
		else {
			TRAP(err,*aDecoder=CImageDecoder::DataNewL(iEikEnv->FsSession(),*aMetadata.iCover));
			if(!err) {
				LOG(ELogGeneral,-1,"GetAlbumArtFilename-- (we have embedded cover)");
				return 0; 
			}
			else LOG0("Instantiating a CImageDecoder for the embedded cover failed. Checking other options.");
		}
	}
	
	//check for KAlbumCoverNameGeneric
	aMetadata.iFileDirEntry->iParent->GetFullPath(aCoverFilename,ETrue);
	TInt pathLength=aCoverFilename.Length();
	aCoverFilename.Append(KAlbumCoverNameGeneric);
	if((r=GetAlbumArtFilenameHelper(aSize,aCoverFilename,aDecoder))>=0)
		return r;
	
	//check for KAlbumCoverNameGeneric2
	aCoverFilename.SetLength(pathLength);
	aCoverFilename.Append(KAlbumCoverNameGeneric2);
	if((r=GetAlbumArtFilenameHelper(aSize,aCoverFilename,aDecoder))>=0)
		return r;
	
	//if we are here, we need to check if we have valid Artist and Album metadata
	if(aMetadata.iAlbum && aMetadata.iArtist)
	{
		//we can construct Source/__Covers/Artist-Album.jpg
		aMetadata.iFileDirEntry->GetSource()->GetFullPath(aCoverFilename,ETrue);
		aCoverFilename.Append(KCoversFolderName);
		pathLength=aCoverFilename.Length();
		if(pathLength+aMetadata.iArtist->Length()+aMetadata.iAlbum->Length()+6<=KMaxFileName) //6= the dash + length of .jpg or .jpeg or .hint
		{
			//check for __Covers/Artist-Album.jpg
			aCoverFilename.Append(*aMetadata.iArtist);
			aCoverFilename.Append('-');
			aCoverFilename.Append(*aMetadata.iAlbum);
			aCoverFilename.Append(KAlbumCoverExtension);
			if((r=GetAlbumArtFilenameHelper(aSize,aCoverFilename,aDecoder))>=0)
				return r;
			
			//if we are here, the file does not exist!
			if((iPreferences->iPFlags&CMLauncherPreferences::EPreferencesCreateCoverHintFiles) &&
					(pathLength+KIgnoreFolderName().Length()+aMetadata.iArtist->Length()+aMetadata.iAlbum->Length()+6<=KMaxFileName)) //filename size requirements
			{
				//check first if the hint file is in the "IGNORE" folder
				aCoverFilename.SetLength(pathLength);
				aCoverFilename.Append(KIgnoreFolderName);
				aCoverFilename.Append(*aMetadata.iArtist);
				aCoverFilename.Append('-');
				aCoverFilename.Append(*aMetadata.iAlbum);
				aCoverFilename.Append(KHintFileExtension);
				if(iEikEnv->FsSession().Entry(aCoverFilename,entry)){
					//the hint file was not found in the IGNORE folder
					//we should create a hint file
					aCoverFilename.SetLength(pathLength);
					aCoverFilename.Append(*aMetadata.iArtist);
					aCoverFilename.Append('-');
					aCoverFilename.Append(*aMetadata.iAlbum);
					aCoverFilename.Append(KHintFileExtension);
					LOG0("Creating hint file for %S",&aCoverFilename);
					//first, we try to make the folder
					if(!iEikEnv->FsSession().MkDir(aCoverFilename.Left(pathLength))){
						//set the entry as hidden
						TTime modifTime;
						modifTime.UniversalTime();
						iEikEnv->FsSession().SetEntry(aCoverFilename.Left(pathLength),modifTime,KEntryAttHidden,0);
					}
					//now we create the file, IF it does not exist
					if(iEikEnv->FsSession().Entry(aCoverFilename,entry)){
//.........这里部分代码省略.........

TBool CTstAppUi::ProcessCommandParametersL(TApaCommand, TFileName& aDocumentName, const TDesC8&)
	{
	aDocumentName.SetLength(0);
	return EFalse;
	}