142 lines
4 KiB
C++
142 lines
4 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2015 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#include <mapnik/plugin.hpp>
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#include <stdexcept>
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#ifdef _WINDOWS
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#define NOMINMAX
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#include <windows.h>
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#define handle HMODULE
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#define dlsym GetProcAddress
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#define dlclose FreeLibrary
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#define dlerror GetLastError
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#define MAPNIK_SUPPORTS_DLOPEN
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#else
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#ifdef MAPNIK_HAS_DLCFN
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#include <dlfcn.h>
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#define MAPNIK_SUPPORTS_DLOPEN
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#endif
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#define handle void *
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#endif
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// TODO - handle/report dlerror
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namespace mapnik
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{
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struct _mapnik_lib_t {
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handle dl;
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};
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PluginInfo::PluginInfo(std::string const& filename,
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std::string const& library_name)
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: filename_(filename),
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name_(),
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module_(new mapnik_lib_t)
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{
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#ifdef _WINDOWS
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if (module_) module_->dl = LoadLibraryA(filename.c_str());
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if (module_ && module_->dl)
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{
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name_func name = reinterpret_cast<name_func>(dlsym(module_->dl, library_name.c_str()));
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if (name) name_ = name();
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}
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#else
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#ifdef MAPNIK_HAS_DLCFN
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if (module_) module_->dl = dlopen(filename.c_str(),RTLD_LAZY);
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if (module_ && module_->dl)
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{
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name_func name = reinterpret_cast<name_func>(dlsym(module_->dl, library_name.c_str()));
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if (name) name_ = name();
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}
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#else
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throw std::runtime_error("no support for loading dynamic objects (Mapnik not compiled with -DMAPNIK_HAS_DLCFN)");
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#endif
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#endif
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}
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PluginInfo::~PluginInfo()
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{
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if (module_)
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{
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#ifdef MAPNIK_SUPPORTS_DLOPEN
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/*
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We do not call dlclose for plugins that link libgdal.
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This is a terrible hack, but necessary to prevent crashes
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at exit when gdal attempts to shutdown. The problem arises
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when Mapnik is used with another library that uses thread-local
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storage (like libuv). In this case GDAL also tries to cleanup thread
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local storage and leaves things in a state that causes libuv to crash.
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This is partially fixed by http://trac.osgeo.org/gdal/ticket/5509 but only
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in the case that gdal is linked as a shared library. This workaround therefore
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prevents crashes with gdal 1.11.x and gdal 2.x when using a static libgdal.
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*/
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if (module_->dl && name_ != "gdal" && name_ != "ogr")
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{
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dlclose(module_->dl),module_->dl=0;
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}
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#endif
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delete module_;
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}
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}
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void * PluginInfo::get_symbol(std::string const& sym_name) const
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{
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#ifdef MAPNIK_SUPPORTS_DLOPEN
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return static_cast<void *>(dlsym(module_->dl, sym_name.c_str()));
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#else
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return NULL;
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#endif
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}
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std::string const& PluginInfo::name() const
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{
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return name_;
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}
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bool PluginInfo::valid() const
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{
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#ifdef MAPNIK_SUPPORTS_DLOPEN
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if (module_ && module_->dl && !name_.empty()) return true;
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#endif
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return false;
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}
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std::string PluginInfo::get_error() const
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{
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return std::string("could not open: '") + name_ + "'";
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}
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void PluginInfo::init()
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{
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// do any initialization needed
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}
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void PluginInfo::exit()
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{
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// do any shutdown needed
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}
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}
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