Line data    Source code

       1             : /******************************************************************************
       2             :  *
       3             :  * Project:  CPL - Common Portability Library
       4             :  * Purpose:  File handler that uses a temporary file, and upload file on close
       5             :  * Author:   Even Rouault, even.rouault at spatialys.com
       6             :  *
       7             :  ******************************************************************************
       8             :  * Copyright (c) 2020, Even Rouault <even.rouault at spatialys.com>
       9             :  *
      10             :  * Permission is hereby granted, free of charge, to any person obtaining a
      11             :  * copy of this software and associated documentation files (the "Software"),
      12             :  * to deal in the Software without restriction, including without limitation
      13             :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      14             :  * and/or sell copies of the Software, and to permit persons to whom the
      15             :  * Software is furnished to do so, subject to the following conditions:
      16             :  *
      17             :  * The above copyright notice and this permission notice shall be included
      18             :  * in all copies or substantial portions of the Software.
      19             :  *
      20             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
      21             :  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      22             :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
      23             :  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
      24             :  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
      25             :  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
      26             :  * DEALINGS IN THE SOFTWARE.
      27             :  ****************************************************************************/
      28             : 
      29             : #include "cpl_vsi_virtual.h"
      30             : 
      31             : #include <algorithm>
      32             : #include <vector>
      33             : 
      34             : /************************************************************************/
      35             : /*                        VSIUploadOnCloseHandle                        */
      36             : /************************************************************************/
      37             : 
      38             : class VSIUploadOnCloseHandle final : public VSIVirtualHandle
      39             : {
      40             :     VSIVirtualHandleUniquePtr m_poWritableHandle;
      41             :     std::string m_osTmpFilename;
      42             :     VSIVirtualHandleUniquePtr m_fpTemp;
      43             : 
      44             :     VSIUploadOnCloseHandle(const VSIUploadOnCloseHandle &) = delete;
      45             :     VSIUploadOnCloseHandle &operator=(const VSIUploadOnCloseHandle &) = delete;
      46             : 
      47             :   public:
      48           5 :     VSIUploadOnCloseHandle(VSIVirtualHandleUniquePtr &&poWritableHandle,
      49             :                            const std::string &osTmpFilename,
      50             :                            VSIVirtualHandleUniquePtr &&fpTemp)
      51          10 :         : m_poWritableHandle(std::move(poWritableHandle)),
      52           5 :           m_osTmpFilename(osTmpFilename), m_fpTemp(std::move(fpTemp))
      53             :     {
      54           5 :     }
      55             : 
      56             :     ~VSIUploadOnCloseHandle() override;
      57             : 
      58          31 :     int Seek(vsi_l_offset nOffset, int nWhence) override
      59             :     {
      60          31 :         return m_fpTemp->Seek(nOffset, nWhence);
      61             :     }
      62             : 
      63          27 :     vsi_l_offset Tell() override
      64             :     {
      65          27 :         return m_fpTemp->Tell();
      66             :     }
      67             : 
      68          35 :     size_t Read(void *pBuffer, size_t nSize, size_t nCount) override
      69             :     {
      70          35 :         return m_fpTemp->Read(pBuffer, nSize, nCount);
      71             :     }
      72             : 
      73          13 :     size_t Write(const void *pBuffer, size_t nSize, size_t nCount) override
      74             :     {
      75          13 :         return m_fpTemp->Write(pBuffer, nSize, nCount);
      76             :     }
      77             : 
      78           1 :     int Eof() override
      79             :     {
      80           1 :         return m_fpTemp->Eof();
      81             :     }
      82             : 
      83           0 :     int Flush() override
      84             :     {
      85           0 :         return m_fpTemp->Flush();
      86             :     }
      87             : 
      88             :     int Close() override;
      89             : 
      90           0 :     int Truncate(vsi_l_offset nNewSize) override
      91             :     {
      92           0 :         return m_fpTemp->Truncate(nNewSize);
      93             :     }
      94             : 
      95           0 :     VSIRangeStatus GetRangeStatus(vsi_l_offset nOffset,
      96             :                                   vsi_l_offset nLength) override
      97             :     {
      98           0 :         return m_fpTemp->GetRangeStatus(nOffset, nLength);
      99             :     }
     100             : };
     101             : 
     102             : /************************************************************************/
     103             : /*                      ~VSIUploadOnCloseHandle()                       */
     104             : /************************************************************************/
     105             : 
     106          10 : VSIUploadOnCloseHandle::~VSIUploadOnCloseHandle()
     107             : {
     108           5 :     VSIUploadOnCloseHandle::Close();
     109           5 :     if (!m_osTmpFilename.empty())
     110           0 :         VSIUnlink(m_osTmpFilename.c_str());
     111          10 : }
     112             : 
     113             : /************************************************************************/
     114             : /*                              Close()                                 */
     115             : /************************************************************************/
     116             : 
     117          10 : int VSIUploadOnCloseHandle::Close()
     118             : {
     119          10 :     if (m_fpTemp == nullptr)
     120           5 :         return -1;
     121             : 
     122             :     // Copy temporary files to m_poWritableHandle
     123           5 :     if (m_fpTemp->Seek(0, SEEK_END) != 0)
     124             :     {
     125           0 :         m_fpTemp.reset();
     126           0 :         return -1;
     127             :     }
     128           5 :     const auto nSize = m_fpTemp->Tell();
     129           5 :     m_fpTemp->Seek(0, SEEK_SET);
     130           5 :     constexpr size_t CHUNK_SIZE = 1024 * 1024;
     131           5 :     vsi_l_offset nOffset = 0;
     132          15 :     std::vector<GByte> abyBuffer(CHUNK_SIZE);
     133           8 :     while (nOffset < nSize)
     134             :     {
     135             :         size_t nToRead = static_cast<size_t>(
     136           4 :             std::min(nSize - nOffset, static_cast<vsi_l_offset>(CHUNK_SIZE)));
     137           8 :         if (m_fpTemp->Read(&abyBuffer[0], nToRead, 1) != 1 ||
     138           4 :             m_poWritableHandle->Write(&abyBuffer[0], nToRead, 1) != 1)
     139             :         {
     140           1 :             m_fpTemp.reset();
     141           1 :             return -1;
     142             :         }
     143           3 :         nOffset += nToRead;
     144             :     }
     145           4 :     m_fpTemp.reset();
     146           4 :     return m_poWritableHandle->Close();
     147             : }
     148             : 
     149             : /************************************************************************/
     150             : /*                    VSICreateUploadOnCloseFile()                      */
     151             : /************************************************************************/
     152             : 
     153             : VSIVirtualHandle *
     154           5 : VSICreateUploadOnCloseFile(VSIVirtualHandleUniquePtr &&poWritableHandle,
     155             :                            VSIVirtualHandleUniquePtr &&poTmpFile,
     156             :                            const std::string &osTmpFilename)
     157             : {
     158           5 :     const bool deleted = VSIUnlink(osTmpFilename.c_str()) == 0;
     159           5 :     return new VSIUploadOnCloseHandle(std::move(poWritableHandle),
     160          10 :                                       deleted ? std::string() : osTmpFilename,
     161          10 :                                       std::move(poTmpFile));
     162             : }