cpl_vsil_plugin.cpp

/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Implement VSI large file api for plugins
 * Author:   Thomas Bonfort, thomas.bonfort@airbus.com
 *
 ******************************************************************************
 * Copyright (c) 2019, Thomas Bonfort <thomas.bonfort@airbus.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_port.h"
#include "cpl_vsil_plugin.h"

//! @cond Doxygen_Suppress
#ifndef DOXYGEN_SKIP

namespace cpl
{

VSIPluginHandle::VSIPluginHandle(VSIPluginFilesystemHandler *poFSIn,
                                 void *cbDataIn)
    : poFS(poFSIn), cbData(cbDataIn)
{
}

VSIPluginHandle::~VSIPluginHandle()
{
    if (cbData)
    {
        VSIPluginHandle::Close();
    }
}

int VSIPluginHandle::Seek(vsi_l_offset nOffset, int nWhence)
{
    return poFS->Seek(cbData, nOffset, nWhence);
}

vsi_l_offset VSIPluginHandle::Tell()
{
    return poFS->Tell(cbData);
}

size_t VSIPluginHandle::Read(void *const pBuffer, size_t const nSize,
                             size_t const nMemb)
{
    return poFS->Read(cbData, pBuffer, nSize, nMemb);
}

int VSIPluginHandle::Eof()
{
    return poFS->Eof(cbData);
}

int VSIPluginHandle::Error()
{
    return poFS->Error(cbData);
}

void VSIPluginHandle::ClearErr()
{
    poFS->ClearErr(cbData);
}

int VSIPluginHandle::Close()
{
    int ret = poFS->Close(cbData);
    cbData = nullptr;
    return ret;
}

int VSIPluginHandle::ReadMultiRange(int nRanges, void **ppData,
                                    const vsi_l_offset *panOffsets,
                                    const size_t *panSizes)
{
    return poFS->ReadMultiRange(cbData, nRanges, ppData, panOffsets, panSizes);
}

void VSIPluginHandle::AdviseRead(int nRanges, const vsi_l_offset *panOffsets,
                                 const size_t *panSizes)
{
    poFS->AdviseRead(cbData, nRanges, panOffsets, panSizes);
}

VSIRangeStatus VSIPluginHandle::GetRangeStatus(vsi_l_offset nOffset,
                                               vsi_l_offset nLength)
{
    return poFS->GetRangeStatus(cbData, nOffset, nLength);
}

size_t VSIPluginHandle::Write(const void *pBuffer, size_t nSize, size_t nCount)
{
    return poFS->Write(cbData, pBuffer, nSize, nCount);
}

int VSIPluginHandle::Flush()
{
    return poFS->Flush(cbData);
}

int VSIPluginHandle::Truncate(vsi_l_offset nNewSize)
{
    return poFS->Truncate(cbData, nNewSize);
}

VSIPluginFilesystemHandler::VSIPluginFilesystemHandler(
    const char *pszPrefix, const VSIFilesystemPluginCallbacksStruct *cbIn)
    : m_Prefix(pszPrefix), m_cb(nullptr)
{
    m_cb = new VSIFilesystemPluginCallbacksStruct(*cbIn);
}

VSIPluginFilesystemHandler::~VSIPluginFilesystemHandler()
{
    delete m_cb;
}

VSIVirtualHandle *
VSIPluginFilesystemHandler::Open(const char *pszFilename, const char *pszAccess,
                                 bool bSetError,
                                 CSLConstList /* papszOptions */)
{
    if (!IsValidFilename(pszFilename))
        return nullptr;
    void *cbData = m_cb->open(m_cb->pUserData, GetCallbackFilename(pszFilename),
                              pszAccess);
    if (cbData == nullptr)
    {
        if (bSetError)
        {
            VSIError(VSIE_FileError, "%s: %s", pszFilename, strerror(errno));
        }
        return nullptr;
    }
    if (m_cb->nBufferSize == 0)
    {
        return new VSIPluginHandle(this, cbData);
    }
    else
    {
        return VSICreateCachedFile(
            new VSIPluginHandle(this, cbData), m_cb->nBufferSize,
            (m_cb->nCacheSize < m_cb->nBufferSize) ? m_cb->nBufferSize
                                                   : m_cb->nCacheSize);
    }
}

const char *
VSIPluginFilesystemHandler::GetCallbackFilename(const char *pszFilename)
{
    return pszFilename + strlen(m_Prefix);
}

bool VSIPluginFilesystemHandler::IsValidFilename(const char *pszFilename)
{
    if (!STARTS_WITH_CI(pszFilename, m_Prefix))
        return false;
    return true;
}

int VSIPluginFilesystemHandler::Stat(const char *pszFilename,
                                     VSIStatBufL *pStatBuf, int nFlags)
{
    if (!IsValidFilename(pszFilename))
    {
        errno = EBADF;
        return -1;
    }

    memset(pStatBuf, 0, sizeof(VSIStatBufL));

    int nRet = 0;
    if (m_cb->stat != nullptr)
    {
        nRet = m_cb->stat(m_cb->pUserData, GetCallbackFilename(pszFilename),
                          pStatBuf, nFlags);
    }
    else
    {
        nRet = -1;
    }
    return nRet;
}

int VSIPluginFilesystemHandler::Seek(void *pFile, vsi_l_offset nOffset,
                                     int nWhence)
{
    if (m_cb->seek != nullptr)
    {
        return m_cb->seek(pFile, nOffset, nWhence);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Seek not implemented for %s plugin",
             m_Prefix);
    return -1;
}

vsi_l_offset VSIPluginFilesystemHandler::Tell(void *pFile)
{
    if (m_cb->tell != nullptr)
    {
        return m_cb->tell(pFile);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Tell not implemented for %s plugin",
             m_Prefix);
    return -1;
}

size_t VSIPluginFilesystemHandler::Read(void *pFile, void *pBuffer,
                                        size_t nSize, size_t nCount)
{
    if (m_cb->read != nullptr)
    {
        return m_cb->read(pFile, pBuffer, nSize, nCount);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Read not implemented for %s plugin",
             m_Prefix);
    return -1;
}

int VSIPluginFilesystemHandler::HasOptimizedReadMultiRange(
    const char * /*pszPath*/)
{
    if (m_cb->read_multi_range != nullptr)
    {
        return TRUE;
    }
    return FALSE;
}

VSIRangeStatus VSIPluginFilesystemHandler::GetRangeStatus(void *pFile,
                                                          vsi_l_offset nOffset,
                                                          vsi_l_offset nLength)
{
    if (m_cb->get_range_status != nullptr)
    {
        return m_cb->get_range_status(pFile, nOffset, nLength);
    }
    return VSI_RANGE_STATUS_UNKNOWN;
}

int VSIPluginFilesystemHandler::ReadMultiRange(void *pFile, int nRanges,
                                               void **ppData,
                                               const vsi_l_offset *panOffsets,
                                               const size_t *panSizes)
{
    if (m_cb->read_multi_range == nullptr)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Read not implemented for %s plugin", m_Prefix);
        return -1;
    }
    int iRange;
    int nMergedRanges = 1;
    for (iRange = 0; iRange < nRanges - 1; iRange++)
    {
        if (panOffsets[iRange] + panSizes[iRange] != panOffsets[iRange + 1])
        {
            nMergedRanges++;
        }
    }
    if (nMergedRanges == nRanges)
    {
        return m_cb->read_multi_range(pFile, nRanges, ppData, panOffsets,
                                      panSizes);
    }

    vsi_l_offset *mOffsets = new vsi_l_offset[nMergedRanges];
    size_t *mSizes = new size_t[nMergedRanges];
    char **mData = new char *[nMergedRanges];

    int curRange = 0;
    mSizes[curRange] = panSizes[0];
    mOffsets[curRange] = panOffsets[0];
    for (iRange = 0; iRange < nRanges - 1; iRange++)
    {
        if (panOffsets[iRange] + panSizes[iRange] == panOffsets[iRange + 1])
        {
            mSizes[curRange] += panSizes[iRange + 1];
        }
        else
        {
            mData[curRange] = new char[mSizes[curRange]];
            // start a new range
            curRange++;
            mSizes[curRange] = panSizes[iRange + 1];
            mOffsets[curRange] = panOffsets[iRange + 1];
        }
    }
    mData[curRange] = new char[mSizes[curRange]];

    int ret = m_cb->read_multi_range(pFile, nMergedRanges,
                                     reinterpret_cast<void **>(mData), mOffsets,
                                     mSizes);

    curRange = 0;
    size_t curOffset = panSizes[0];
    memcpy(ppData[0], mData[0], panSizes[0]);
    for (iRange = 0; iRange < nRanges - 1; iRange++)
    {
        if (panOffsets[iRange] + panSizes[iRange] == panOffsets[iRange + 1])
        {
            memcpy(ppData[iRange + 1], mData[curRange] + curOffset,
                   panSizes[iRange + 1]);
            curOffset += panSizes[iRange + 1];
        }
        else
        {
            curRange++;
            memcpy(ppData[iRange + 1], mData[curRange], panSizes[iRange + 1]);
            curOffset = panSizes[iRange + 1];
        }
    }

    delete[] mOffsets;
    delete[] mSizes;
    for (int i = 0; i < nMergedRanges; i++)
    {
        delete[] mData[i];
    }
    delete[] mData;

    return ret;
}

void VSIPluginFilesystemHandler::AdviseRead(void *pFile, int nRanges,
                                            const vsi_l_offset *panOffsets,
                                            const size_t *panSizes)
{
    if (m_cb->advise_read != nullptr)
    {
        m_cb->advise_read(pFile, nRanges, panOffsets, panSizes);
    }
    else
    {
        if (!m_bWarnedAdviseReadImplemented)
        {
            m_bWarnedAdviseReadImplemented = true;
            CPLDebug("VSIPlugin", "AdviseRead() not implemented");
        }
    }
}

int VSIPluginFilesystemHandler::Eof(void *pFile)
{
    if (m_cb->eof != nullptr)
    {
        return m_cb->eof(pFile);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Eof not implemented for %s plugin",
             m_Prefix);
    return -1;
}

int VSIPluginFilesystemHandler::Error(void *pFile)
{
    if (m_cb->error)
    {
        return m_cb->error(pFile);
    }
    CPLDebug("CPL", "Error() not implemented for %s plugin", m_Prefix);
    return 0;
}

void VSIPluginFilesystemHandler::ClearErr(void *pFile)
{
    if (m_cb->clear_err)
    {
        m_cb->clear_err(pFile);
    }
    else
    {
        CPLDebug("CPL", "ClearErr() not implemented for %s plugin", m_Prefix);
    }
}

int VSIPluginFilesystemHandler::Close(void *pFile)
{
    if (m_cb->close != nullptr)
    {
        return m_cb->close(pFile);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Close not implemented for %s plugin",
             m_Prefix);
    return -1;
}

size_t VSIPluginFilesystemHandler::Write(void *pFile, const void *psBuffer,
                                         size_t nSize, size_t nCount)
{
    if (m_cb->write != nullptr)
    {
        return m_cb->write(pFile, psBuffer, nSize, nCount);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Write not implemented for %s plugin",
             m_Prefix);
    return -1;
}

int VSIPluginFilesystemHandler::Flush(void *pFile)
{
    if (m_cb->flush != nullptr)
    {
        return m_cb->flush(pFile);
    }
    CPLError(CE_Failure, CPLE_AppDefined, "Flush not implemented for %s plugin",
             m_Prefix);
    return -1;
}

int VSIPluginFilesystemHandler::Truncate(void *pFile, vsi_l_offset nNewSize)
{
    if (m_cb->truncate != nullptr)
    {
        return m_cb->truncate(pFile, nNewSize);
    }
    CPLError(CE_Failure, CPLE_AppDefined,
             "Truncate not implemented for %s plugin", m_Prefix);
    return -1;
}

char **VSIPluginFilesystemHandler::ReadDirEx(const char *pszDirname,
                                             int nMaxFiles)
{
    if (!IsValidFilename(pszDirname))
        return nullptr;
    if (m_cb->read_dir != nullptr)
    {
        return m_cb->read_dir(m_cb->pUserData, GetCallbackFilename(pszDirname),
                              nMaxFiles);
    }
    return nullptr;
}

char **VSIPluginFilesystemHandler::SiblingFiles(const char *pszFilename)
{
    if (!IsValidFilename(pszFilename))
        return nullptr;
    if (m_cb->sibling_files != nullptr)
    {
        return m_cb->sibling_files(m_cb->pUserData,
                                   GetCallbackFilename(pszFilename));
    }
    return nullptr;
}

int VSIPluginFilesystemHandler::Unlink(const char *pszFilename)
{
    if (m_cb->unlink == nullptr || !IsValidFilename(pszFilename))
        return -1;
    return unlink(GetCallbackFilename(pszFilename));
}

int VSIPluginFilesystemHandler::Rename(const char *oldpath, const char *newpath)
{
    if (m_cb->rename == nullptr || !IsValidFilename(oldpath) ||
        !IsValidFilename(newpath))
        return -1;
    return m_cb->rename(m_cb->pUserData, GetCallbackFilename(oldpath),
                        GetCallbackFilename(newpath));
}

int VSIPluginFilesystemHandler::Mkdir(const char *pszDirname, long nMode)
{
    if (m_cb->mkdir == nullptr || !IsValidFilename(pszDirname))
        return -1;
    return m_cb->mkdir(m_cb->pUserData, GetCallbackFilename(pszDirname), nMode);
}

int VSIPluginFilesystemHandler::Rmdir(const char *pszDirname)
{
    if (m_cb->rmdir == nullptr || !IsValidFilename(pszDirname))
        return -1;
    return m_cb->rmdir(m_cb->pUserData, GetCallbackFilename(pszDirname));
}
}  // namespace cpl

#endif  // DOXYGEN_SKIP
//! @endcond

int VSIInstallPluginHandler(const char *pszPrefix,
                            const VSIFilesystemPluginCallbacksStruct *poCb)
{
    VSIFilesystemHandler *poHandler =
        new cpl::VSIPluginFilesystemHandler(pszPrefix, poCb);
    // TODO: check pszPrefix starts and ends with a /
    VSIFileManager::InstallHandler(pszPrefix, poHandler);
    return 0;
}

int VSIRemovePluginHandler(const char *pszPrefix)
{
    VSIFileManager::RemoveHandler(pszPrefix);
    return 0;
}

VSIFilesystemPluginCallbacksStruct *
VSIAllocFilesystemPluginCallbacksStruct(void)
{
    return static_cast<VSIFilesystemPluginCallbacksStruct *>(
        VSI_CALLOC_VERBOSE(1, sizeof(VSIFilesystemPluginCallbacksStruct)));
}

void VSIFreeFilesystemPluginCallbacksStruct(
    VSIFilesystemPluginCallbacksStruct *poCb)
{
    CPLFree(poCb);
}