src/python/pystreamredirect.hpp

   1 /*
   2  * This file is part of the SmuView project.
   3  *
   4  * Copyright (C) 2019-2021 Frank Stettner <frank-stettner@gmx.net>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef PYTHON_PYSTREAMREDIRECT_HPP
  21 #define PYTHON_PYSTREAMREDIRECT_HPP
  22
  23 #include <iostream>
  24 #include <memory>
  25 #include <string>
  26
  27 #include <pybind11/pybind11.h>
  28
  29 #include <QObject>
  30
  31 #include "src/python/pystreambuf.hpp"
  32 #include "src/python/smuscriptrunner.hpp"
  33
  34 using std::shared_ptr;
  35 using std::string;
  36
  37 namespace py = pybind11;
  38
  39 namespace sv {
  40 namespace python {
  41
  42 class __attribute__((visibility("hidden"))) PyStreamRedirect : public QObject
  43 {
  44         Q_OBJECT
  45
  46 public:
  47     explicit PyStreamRedirect(shared_ptr<SmuScriptRunner> script_runner) :
  48                 script_runner_(script_runner)
  49         {
  50                 auto sys_module = py::module::import("sys");
  51                 old_stdout_ = sys_module.attr("stdout");
  52                 old_stderr_ = sys_module.attr("stderr");
  53
  54                 auto locale_module = py::module::import("locale");
  55                 auto default_encoding = locale_module.attr("getpreferredencoding")(false);
  56
  57                 stdout_buf_ = new PyStreamBuf(
  58                         py::str(py::getattr(old_stdout_, "encoding", default_encoding)),
  59                         py::str(py::getattr(old_stdout_, "errors", py::str("strict"))));
  60                 auto py_stdout_buf = py::cast(
  61                         stdout_buf_, py::return_value_policy::reference);
  62                 connect(stdout_buf_, &PyStreamBuf::send_string,
  63                         script_runner_.get(), &SmuScriptRunner::send_py_stdout);
  64
  65                 stderr_buf_ = new PyStreamBuf(
  66                         py::str(py::getattr(old_stderr_, "encoding", default_encoding)),
  67                         py::str(py::getattr(old_stderr_, "errors", py::str("backslashreplace"))));
  68                 auto py_stderr_buf = py::cast(
  69                         stderr_buf_, py::return_value_policy::reference);
  70                 connect(stderr_buf_, &PyStreamBuf::send_string,
  71                         script_runner_.get(), &SmuScriptRunner::send_py_stderr);
  72
  73                 sys_module.attr("stdout") = py_stdout_buf;
  74                 sys_module.attr("stderr") = py_stderr_buf;
  75         }
  76
  77         ~PyStreamRedirect()
  78         {
  79                 try {
  80                         auto sys_module = py::module::import("sys");
  81                         sys_module.attr("stdout") = old_stdout_;
  82                         sys_module.attr("stderr") = old_stderr_;
  83                 }
  84                 catch (const py::error_already_set &) {}
  85
  86                 stdout_buf_->py_close();
  87                 stderr_buf_->py_close();
  88
  89                 disconnect(stdout_buf_, &PyStreamBuf::send_string,
  90                         script_runner_.get(), &SmuScriptRunner::send_py_stdout);
  91                 disconnect(stderr_buf_, &PyStreamBuf::send_string,
  92                         script_runner_.get(), &SmuScriptRunner::send_py_stderr);
  93         }
  94
  95 private:
  96         shared_ptr<SmuScriptRunner> script_runner_;
  97         py::object old_stdout_;
  98         py::object old_stderr_;
  99         PyStreamBuf *stdout_buf_;
 100         PyStreamBuf *stderr_buf_;
 101
 102 };
 103
 104 } // namespace python
 105 } // namespace sv
 106
 107 #endif // PYTHON_PYSTREAMREDIRECT_HPP