mirror of https://github.com/vitalif/grive2
91 lines
2.3 KiB
C++
91 lines
2.3 KiB
C++
/*
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grive: an GPL program to sync a local directory with Google Drive
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Copyright (C) 2012 Wan Wai Ho
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2
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of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "Download.hh"
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#include <openssl/evp.h>
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#include <cassert>
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#include <new>
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#include <stdexcept>
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namespace gr {
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Download::Download( const std::string& filename ) :
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m_file( filename.c_str(), std::ios::out | std::ios::binary ),
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m_mdctx( ::EVP_MD_CTX_create() )
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{
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if ( m_mdctx == 0 )
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throw std::bad_alloc() ;
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if ( ::EVP_DigestInit_ex( m_mdctx, ::EVP_md5(), 0 ) != 1 )
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throw std::runtime_error( "cannot create MD5 digest context" ) ;
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if ( !m_file )
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throw std::runtime_error( "cannot open file " + filename + " for writing" ) ;
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}
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Download::Download( const std::string& filename, NoChecksum ) :
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m_file( filename.c_str(), std::ios::out | std::ios::binary ),
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m_mdctx( 0 )
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{
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if ( !m_file )
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throw std::runtime_error( "cannot open file " + filename + " for writing" ) ;
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}
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Download::~Download( )
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{
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if ( m_mdctx != 0 )
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::EVP_MD_CTX_destroy( m_mdctx ) ;
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}
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std::string Download::Finish() const
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{
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std::string result ;
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// get the checksum and return it ;
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if ( m_mdctx != 0 )
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{
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unsigned int size = EVP_MAX_MD_SIZE ;
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result.resize( size ) ;
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if ( ::EVP_DigestFinal_ex( m_mdctx, reinterpret_cast<unsigned char*>(&result[0]), &size ) != 1 )
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throw std::runtime_error( "cannot calculate checksum" ) ;
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result.resize( size ) ;
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}
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return result ;
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}
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std::size_t Download::Callback( char *data, std::size_t size, std::size_t nmemb, Download *pthis )
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{
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assert( pthis != 0 ) ;
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assert( data != 0 ) ;
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std::size_t count = size * nmemb ;
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if ( pthis->m_mdctx != 0 )
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::EVP_DigestUpdate( pthis->m_mdctx, data, count ) ;
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return pthis->m_file.rdbuf()->sputn( data, count ) ;
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}
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} // end of namespace
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