winamp/Src/Plugins/Library/ml_wire/BackgroundDownloader.cpp

#include <vector>
#include <atomic>

#include "Main.h"
#include "Downloaded.h"
#include "BackgroundDownloader.h"

#include "Feeds.h"
#include "DownloadStatus.h"
#include "DownloadsDialog.h"
#include "api__ml_wire.h"
#include "api/service/waServiceFactory.h"
#include "../../..\Components\wac_network\wac_network_http_receiver_api.h"


using namespace Nullsoft::Utility;

#define SIMULTANEOUS_DOWNLOADS 2
std::vector<DownloadToken> downloadsQueue;
LockGuard downloadsQueueLock;

class DownloaderCallback : public ifc_downloadManagerCallback
{
public:
	DownloaderCallback( const wchar_t *url, const wchar_t *destination_filepath, const wchar_t *channel, const wchar_t *item, __time64_t publishDate )
	{
		this->hFile                = INVALID_HANDLE_VALUE;
		this->url                  = _wcsdup( url );
		this->destination_filepath = _wcsdup( destination_filepath );
		this->channel              = _wcsdup( channel );
		this->item                 = _wcsdup( item );
		this->publishDate          = publishDate;
		this->totalSize            = 0;
		this->downloaded           = 0;
	}
	
	void OnInit(DownloadToken token)
	{
		// ---- Inform the download status service of our presence----
		downloadStatus.AddDownloadThread(token, this->channel, this->item, this->destination_filepath);
	}

	void OnConnect(DownloadToken token)
	{
		// ---- retrieve total size
		api_httpreceiver *http = WAC_API_DOWNLOADMANAGER->GetReceiver(token);
		if (http) 
		{
			this->totalSize = http->content_length();
		}

		// ---- create file handle
		hFile = CreateFile(destination_filepath, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
		if ( hFile == INVALID_HANDLE_VALUE ) 
		{
			WAC_API_DOWNLOADMANAGER->CancelDownload(token);
		}		
	}

	void OnData(DownloadToken token, void *data, size_t datalen)
	{
		// ---- OnConnect copied here due to dlmgr OnData called first
		// ---- retrieve total size
		api_httpreceiver *http = WAC_API_DOWNLOADMANAGER->GetReceiver(token);
		if ( !this->totalSize && http ) 
		{
			this->totalSize = http->content_length();
		}

		if ( hFile == INVALID_HANDLE_VALUE )
		{
			// ---- create file handle
			hFile = CreateFile(destination_filepath, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
			if ( hFile == INVALID_HANDLE_VALUE ) 
			{
				WAC_API_DOWNLOADMANAGER->CancelDownload(token);
				return;
			}		
		}
		// ---- OnConnect to be removed once dlmgr is fixed

		// ---- OnData
		// ---- if file handle is invalid, then cancel download
		if ( hFile == INVALID_HANDLE_VALUE )
		{
			WAC_API_DOWNLOADMANAGER->CancelDownload(token);
			return;
		}

		this->downloaded = (size_t)WAC_API_DOWNLOADMANAGER->GetBytesDownloaded(token);

		if ( datalen > 0 ) 
		{
			// ---- hFile is valid handle, and write to disk
			DWORD numWritten = 0;
			WriteFile(hFile, data,(DWORD)datalen, &numWritten, FALSE);
			
			// ---- failed writing the number of datalen characters, cancel download
			if (numWritten != datalen) 
			{
				WAC_API_DOWNLOADMANAGER->CancelDownload(token);
				return;
			}
		}
	
		// if killswitch is turned on, then cancel download
		if ( downloadStatus.UpdateStatus(token, this->downloaded, this->totalSize) )
		{
			WAC_API_DOWNLOADMANAGER->CancelDownload(token);
		}
	}

	void OnCancel(DownloadToken token)
	{
		if ( hFile != INVALID_HANDLE_VALUE ) 
		{
			CloseHandle(hFile);
			DeleteFile(destination_filepath);
		}
		DownloadsUpdated(token,NULL);
		downloadStatus.DownloadThreadDone(token);


		{
			AutoLock lock( downloadsQueueLock );

			size_t l_index = 0;
			for ( DownloadToken &l_download_token : downloadsQueue )
			{
				if ( l_download_token == token )
				{
					downloadsQueue.erase( downloadsQueue.begin() + l_index );
					break;
				}

				++l_index;
			}
		}

		for ( DownloadToken &l_download_token : downloadsQueue )
		{
			if ( WAC_API_DOWNLOADMANAGER->IsPending( l_download_token ) )
			{
				WAC_API_DOWNLOADMANAGER->ResumePendingDownload( l_download_token );
				break;
			}
		}

		this->Release();
	}	

	void OnError(DownloadToken token, int error)
	{
		if ( hFile != INVALID_HANDLE_VALUE ) 
		{
			CloseHandle(hFile);
			DeleteFile(destination_filepath);
		}
		DownloadsUpdated(token,NULL);
		downloadStatus.DownloadThreadDone(token);

		{
			AutoLock lock(downloadsQueueLock);
			for (size_t index = 0; index < downloadsQueue.size(); index++)
			{
				if (downloadsQueue.at(index) == token)
				{
					downloadsQueue.erase(downloadsQueue.begin() + index);
					break;
				}
			}
			for (size_t index = 0; index < downloadsQueue.size(); index++)
			{
				if(WAC_API_DOWNLOADMANAGER->IsPending(downloadsQueue.at(index)))
				{
					WAC_API_DOWNLOADMANAGER->ResumePendingDownload(downloadsQueue.at(index));
					break;
				}
			}
		}
		this->Release();
	}

	void OnFinish( DownloadToken token )
	{
		if ( hFile != INVALID_HANDLE_VALUE )
		{
			CloseHandle( hFile );

			DownloadedFile *data = new DownloadedFile( this->url, this->destination_filepath, this->channel, this->item, this->publishDate );
			data->bytesDownloaded = this->downloaded;
			data->totalSize = this->totalSize;
			{
				AutoLock lock( downloadedFiles );
				downloadedFiles.downloadList.push_back( *data );
				addToLibrary_thread( *data );

				AddPodcastData( *data );

				DownloadsUpdated( token, &downloadedFiles.downloadList[ downloadedFiles.downloadList.size() - 1 ] );
			}
			downloadStatus.DownloadThreadDone( token );
			delete data;
		}
		else
		{
			DownloadsUpdated( token, NULL );
			downloadStatus.DownloadThreadDone( token );
		}

		{
			AutoLock lock( downloadsQueueLock );
			size_t l_index = 0;
			for ( DownloadToken &l_download_token : downloadsQueue )
			{
				if ( l_download_token == token )
				{
					downloadsQueue.erase( downloadsQueue.begin() + l_index );
					break;
				}

				++l_index;
			}

			for ( DownloadToken &l_download_token : downloadsQueue )
			{
				if ( WAC_API_DOWNLOADMANAGER->IsPending( l_download_token ) )
				{
					WAC_API_DOWNLOADMANAGER->ResumePendingDownload( l_download_token );
					break;
				}
			}
		}

		this->Release();
	}


	int GetSource( wchar_t *source, size_t source_cch )
	{
		return wcscpy_s( source, source_cch, this->channel );
	}

	int GetTitle( wchar_t *title, size_t title_cch )
	{
		return wcscpy_s( title, title_cch, this->item );
	}

	int GetLocation( wchar_t *location, size_t location_cch )
	{
		return wcscpy_s( location, location_cch, this->destination_filepath );
	}


	size_t AddRef()
	{
		return _ref_count.fetch_add( 1 );
	}

	size_t Release()
	{
		if ( _ref_count.load() == 0 )
			return _ref_count.load();

		LONG r = _ref_count.fetch_sub( 1 );
		if ( r == 0 )
			delete( this );

		return r;
	}

private: // private destructor so no one accidentally calls delete directly on this reference counted object
	~DownloaderCallback()
	{
		if ( url )
			free( url );

		if ( destination_filepath )
			free( destination_filepath );

		if ( channel )
			free( channel );

		if ( item )
			free( item );
	}

protected:
	RECVS_DISPATCH;

private:
	HANDLE     hFile;
	wchar_t    *url;
	wchar_t    *destination_filepath;
	wchar_t    *channel;
	wchar_t    *item;
	__time64_t  publishDate;
	size_t      totalSize;
	size_t      downloaded;

	std::atomic<std::size_t> _ref_count = 1;
};

void BackgroundDownloader::Download( const wchar_t *url, const wchar_t *savePath, const wchar_t *channel, const wchar_t *item, __time64_t publishDate )
{
	DownloaderCallback *callback = new DownloaderCallback( url, savePath, channel, item, publishDate );
	{
		Nullsoft::Utility::AutoLock lock( downloadsQueueLock );
		if ( downloadsQueue.size() < SIMULTANEOUS_DOWNLOADS )
		{
			DownloadToken dt = WAC_API_DOWNLOADMANAGER->DownloadEx( AutoChar( url ), callback, api_downloadManager::DOWNLOADEX_CALLBACK | api_downloadManager::DOWNLOADEX_UI );
			downloadsQueue.push_back( dt );
		}
		else
		{
			DownloadToken dt = WAC_API_DOWNLOADMANAGER->DownloadEx( AutoChar( url ), callback, api_downloadManager::DOWNLOADEX_CALLBACK | api_downloadManager::DOWNLOADEX_PENDING | api_downloadManager::DOWNLOADEX_UI );
			downloadsQueue.push_back( dt );
		}
	}
}

BackgroundDownloader downloader;

#define CBCLASS DownloaderCallback
START_DISPATCH;
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONFINISH,    OnFinish )
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONCANCEL,    OnCancel )
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONERROR,     OnError )
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONDATA,      OnData )
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONCONNECT,   OnConnect )
VCB( IFC_DOWNLOADMANAGERCALLBACK_ONINIT,      OnInit )
CB(  IFC_DOWNLOADMANAGERCALLBACK_GETSOURCE,   GetSource )
CB(  IFC_DOWNLOADMANAGERCALLBACK_GETTITLE,    GetTitle )
CB(  IFC_DOWNLOADMANAGERCALLBACK_GETLOCATION, GetLocation )
CB(  ADDREF, AddRef )
CB(  RELEASE, Release )
END_DISPATCH;
#undef CBCLASS