Set up PYTHONHOME dynamically.

Author: SylvainCorlay

.appveyor.yml

@@ -35,7 +35,7 @@ install:
   # Build and install xeus-python
   - mkdir build
   - cd build
-  - cmake -G "NMake Makefiles" -D CMAKE_INSTALL_PREFIX=%MINICONDA%\\Library -D XEXTRA_JUPYTER_DATA_DIR=%MINICONDA%\\share\\jupyter -D BUILD_TESTS=ON ..
+  - cmake -G "NMake Makefiles" -D CMAKE_INSTALL_PREFIX=%MINICONDA%\\Library -D XEXTRA_JUPYTER_DATA_DIR=%MINICONDA%\\share\\jupyter -D BUILD_TESTS=ON -D XEUS_PYTHONHOME_RELPATH=..\\ ..
   - nmake
   - nmake install
   # Install test dependencies

.travis.yml

@@ -64,13 +64,14 @@ install:
     # Build and install xeus-python
     - mkdir build
     - cd build
-    - cmake -D CMAKE_INSTALL_PREFIX=$HOME/miniconda -D DOWNLOAD_GTEST=ON -D PYTHON_EXECUTABLE=`which python` -D XEUS_PYTHONHOME="$HOME/miniconda" -D CMAKE_INSTALL_LIBDIR=lib -DCMAKE_C_COMPILER=$CC -DCMAKE_CXX_COMPILER=$CXX ..
+    - cmake -D CMAKE_INSTALL_PREFIX=$HOME/miniconda -D DOWNLOAD_GTEST=ON -D PYTHON_EXECUTABLE=`which python` -D CMAKE_INSTALL_LIBDIR=lib -DCMAKE_C_COMPILER=$CC -DCMAKE_CXX_COMPILER=$CXX ..
     - make -j2 install
 script:
     # For Python 2, activate the kernel_test Python3 environment
     - if [[ "$PY" == "2" ]]; then
         source activate kernel_test;
         jupyter kernelspec install --sys-prefix ../share/jupyter/kernels/xpython;
+        source activate root;
       fi
     - cd test
     - ./test_xeus_python

CMakeLists.txt

@@ -105,7 +105,6 @@ set(XEUS_PYTHON_SRC
     src/xlinecache.hpp
     src/xptvsd_client.cpp
     src/xptvsd_client.hpp
-    src/xpythonhome.cpp
     src/xstream.cpp
     src/xstream.hpp
     src/xtraceback.cpp
@@ -118,14 +117,21 @@ set(XEUS_PYTHON_HEADERS
     include/xeus-python/xdebugger.hpp
     include/xeus-python/xeus_python_config.hpp
     include/xeus-python/xinterpreter.hpp
-    include/xeus-python/xpythonhome.hpp
+)
+
+set(XPYTHON_SRC
+    src/main.cpp
+    src/xpythonhome.hpp
+    src/xpythonhome.cpp
+    src/xpaths.hpp
+    src/xpaths.cpp
 )
 
 # xeus-python is the target for the library
 add_library(xeus-python SHARED ${XEUS_PYTHON_SRC} ${XEUS_PYTHON_HEADERS})
 
 # xpython is the target for the kernel executable
-add_executable(xpython src/main.cpp)
+add_executable(xpython ${XPYTHON_SRC})
 set_target_properties(xpython PROPERTIES ENABLE_EXPORTS 1)
 target_link_libraries(xpython PRIVATE pybind11::pybind11 xeus-python INTERFACE pybind11_json)
 
@@ -158,7 +164,11 @@ set_target_properties(xeus-python PROPERTIES
                       SOVERSION ${XPYT_VERSION_MAJOR}
                       OUTPUT_NAME "libxeus-python")
 
-target_compile_definitions(xeus-python PUBLIC "XEUS_PYTHON_EXPORTS" XEUS_PYTHONHOME="${PYTHON_PREFIX}")
+target_compile_definitions(xeus-python PUBLIC "XEUS_PYTHON_EXPORTS")
+
+if (XEUS_PYTHONHOME_RELPATH)
+    target_compile_definitions(xpython PRIVATE XEUS_PYTHONHOME_RELPATH=${XEUS_PYTHONHOME_RELPATH})
+endif()
 
 #########
 # Tests #

include/xeus-python/xpythonhome.hpp

@@ -20,9 +20,10 @@
 #include "pybind11/pybind11.h"
 
 #include "xeus-python/xinterpreter.hpp"
-#include "xeus-python/xpythonhome.hpp"
 #include "xeus-python/xdebugger.hpp"
 
+#include "xpythonhome.hpp"
+
 namespace py = pybind11;
 
 std::string extract_filename(int& argc, char* argv[])

src/main.cpp

@@ -0,0 +1,96 @@
+/***************************************************************************
+* Copyright (c) 2018, Martin Renou, Johan Mabille, Sylvain Corlay and      *
+* Wolf Vollprecht                                                          *
+*                                                                          *
+* Distributed under the terms of the BSD 3-Clause License.                 *
+*                                                                          *
+* The full license is in the file LICENSE, distributed with this software. *
+****************************************************************************/
+
+#include "xpaths.hpp"
+
+#include <string>
+#include <cstring>
+
+#if defined(__linux__)
+#  include <unistd.h>
+#endif
+#if defined(_WIN32)
+#  if defined(NOMINMAX)
+#    include <windows.h>
+#  else
+#    define NOMINMAX
+#    include <windows.h>
+#    undef NOMINMAX
+#  endif
+#endif
+#ifdef __APPLE__
+#  include <cstdint>
+#  include <mach-o/dyld.h>
+#endif
+#if defined(__sun)
+#  include <stdlib.h>
+#endif
+
+namespace xpyt
+{
+    std::string executable_path()
+    {
+        std::string path;
+        char buffer[1024];
+        std::memset(buffer, '\0', sizeof(buffer));
+#if defined(__linux__)
+        if (readlink("/proc/self/exe", buffer, sizeof(buffer)) != -1)
+        {
+            path = buffer;
+        }
+        else
+        {
+            // failed to determine run path
+        }
+#elif defined (_WIN32)
+        if (GetModuleFileName(nullptr, buffer, sizeof(buffer)) != 0)
+        {
+            path = buffer;
+        }
+        else
+        {
+            // failed to determine run path
+        }
+#elif defined (__APPLE__)
+        std::uint32_t size = sizeof(buffer);
+        if(_NSGetExecutablePath(buffer, &size) == 0)
+        {
+            path = buffer;
+        }
+        else
+        {
+            // failed to determine run path
+        }
+#elif defined (__FreeBSD__)
+        int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
+        if (sysctl(mib, 4, buffer, sizeof(buffer), NULL, 0) != -1)
+        {
+            path = buffer;
+        }
+        else
+        {
+            // failed to determine run path
+        }
+#elif defined(__sun)
+        path = getexecname();
+#endif
+        return path;
+    }
+    
+    std::string prefix_path()
+    {
+        std::string path = executable_path();
+#if defined (_WIN32)
+        char separator = '\\';
+#else
+        char separator = '/';
+#endif
+        return path.substr(0, path.find_last_of("/\\")) + separator + ".." + separator;
+    }
+}

src/xpaths.cpp

@@ -0,0 +1,29 @@
+/***************************************************************************
+* Copyright (c) Johan Mabille, Sylvain Corlay and Wolf Vollprecht          *
+* Copyright (c) QuantStack                                                 *
+*                                                                          *
+* Distributed under the terms of the BSD 3-Clause License.                 *
+*                                                                          *
+* The full license is in the file LICENSE, distributed with this software. *
+****************************************************************************/
+
+#ifndef XPYT_PATHS_HPP
+#define XPYT_PATHS_HPP
+
+#include <string>
+
+namespace xpyt
+{
+    /*******************
+     * executable_path *
+     *******************/
+
+    std::string executable_path();
+    
+    /*******************
+     * prefix_path *
+     *******************/
+
+    std::string prefix_path();
+}
+#endif

src/xpaths.hpp

@@ -7,22 +7,33 @@
 * The full license is in the file LICENSE, distributed with this software. *
 ****************************************************************************/
 
-#include "xeus-python/xpythonhome.hpp"
+#include "pybind11/pybind11.h"
+
+#include <iostream>
+#include <string>
+
+#include "xeus-python/xeus_python_config.hpp"
+
+#include "xpythonhome.hpp"
+#include "xpaths.hpp"
 
 namespace xpyt
 {
-    // This functino must not be inlined in the header.
-    // get_pythonhome and set_pythonhome must remain
-    // in different compilation units to avoid compiler
-    // optimization in set_pythonhome that results
-    // in a relocation issue with conda.
-    const char* get_pythonhome()
+    void set_pythonhome()
     {
-#ifdef XEUS_PYTHONHOME
-        return XEUS_PYTHONHOME;
+// The XEUS_PYTHONHOME_RELPATH compile-time definition can be used.
+// To specify the PYTHONHOME location as a relative path to the PREFIX.
+#if defined(XEUS_PYTHONHOME_RELPATH)
+        static const std::string pythonhome = prefix_path() + XPYT_STRINGIFY(XEUS_PYTHONHOME_RELPATH);
 #else
-        return "";
+        static const std::string pythonhome = prefix_path();
+#endif
+
+#if PY_MAJOR_VERSION == 2
+        Py_SetPythonHome(const_cast<char*>(pythonhome.c_str()));
+#else
+        static const std::wstring wstr(pythonhome.cbegin(), pythonhome.cend());;
+        Py_SetPythonHome(const_cast<wchar_t*>(wstr.c_str()));
 #endif
     }
 }
-

src/xpythonhome.cpp

@@ -0,0 +1,18 @@
+/***************************************************************************
+* Copyright (c) 2018, Martin Renou, Johan Mabille, Sylvain Corlay and      *
+* Wolf Vollprecht                                                          *
+*                                                                          *
+* Distributed under the terms of the BSD 3-Clause License.                 *
+*                                                                          *
+* The full license is in the file LICENSE, distributed with this software. *
+****************************************************************************/
+
+#ifndef XEUS_PYTHONHOME_HPP
+#define XEUS_PYTHONHOME_HPP
+
+namespace xpyt
+{
+    void set_pythonhome();
+}
+#endif
+

src/xpythonhome.hpp

@@ -77,7 +77,6 @@ find_package(Threads)
 include_directories(${GTEST_INCLUDE_DIRS} SYSTEM)
 
 set(XEUS_PYTHON_TESTS
-    ../src/xpythonhome.cpp
     ../src/xutils.cpp
     test_debugger.cpp
     xeus_client.hpp

test/CMakeLists.txt

@@ -779,11 +779,7 @@ void start_kernel()
     dump_connection_file();
     std::thread kernel([]()
     {
-#if WIN32
-        std::string cmd = ".\\..\\xpython -f " + KERNEL_JSON + "&";
-#else
-        std::string cmd = "./../xpython -f " + KERNEL_JSON + "&";
-#endif
+        std::string cmd = "xpython -f " + KERNEL_JSON + "&";
         int ret2 = std::system(cmd.c_str());
     });
     std::this_thread::sleep_for(2s);