cmake: add python support

FindCython.cmake was taken from
https://github.com/thewtex/cython-cmake-example. The UseCython module
works, but since it is lacking an installation target setup.py will be
used instead.

CMakeLists.txt

@@ -42,6 +42,10 @@ HexVersion(PACKAGE_VERSION_NUM ${PROJECT_VERSION_MAJOR} ${PROJECT_VERSION_MINOR}
 
 include(GNUInstallDirs)
 
+# For Python bindings and documentation
+# (Must be called before PythonLibs for matching versions.)
+find_package(PythonInterp)
+
 # Auto-detection of features that can be toggled
 find_package(OpenSSL 1.0.1  QUIET)
 find_package(Libev 4.15     QUIET)
@@ -55,8 +59,13 @@ find_package(Jansson  2.5   QUIET)
 set(ENABLE_HPACK_TOOLS_DEFAULT ${JANSSON_FOUND})
 find_package(Libevent 2.0.8 QUIET COMPONENTS openssl)
 set(ENABLE_EXAMPLES_DEFAULT ${LIBEVENT_OPENSSL_FOUND})
-# XXX auto-detect python
-set(ENABLE_PYTHON_BINDINGS_DEFAULT OFF)
+find_package(Cython         QUIET)
+find_package(PythonLibs     QUIET)
+if(CYTHON_FOUND AND PYTHONLIBS_FOUND)
+  set(ENABLE_PYTHON_BINDINGS_DEFAULT ON)
+else()
+  set(ENABLE_PYTHON_BINDINGS_DEFAULT OFF)
+endif()
 
 find_package(LibXml2        QUIET)
 set(WITH_LIBXML2_DEFAULT    ${LIBXML2_FOUND})
@@ -68,12 +77,6 @@ set(WITH_SPDYLAY_DEFAULT    ${SPDYLAY_FOUND})
 include(CMakeOptions.txt)
 
 find_package(PkgConfig 0.20)
-# For Python bindings and documentation
-find_package(PythonInterp)
-# XXX fail only when "ON" instead of "CHECK"?
-if(ENABLE_PYTHON_BINDINGS)
-endif()
-# AM_PATH_PYTHON([2.7],, [:])
 
 if(ENABLE_LIB_ONLY)
   set(ENABLE_APP            OFF)
@@ -82,21 +85,6 @@ if(ENABLE_LIB_ONLY)
   set(ENABLE_PYTHON_BINDINGS OFF)
 endif()
 
-if(ENABLE_PYTHON_BINDINGS)
-  find_package(PythonLibs 2.7 REQUIRED)
-  # XXX find cython
-endif()
-# if [test "x$request_python_bindings" != "xno"]; then
-#   AX_PYTHON_DEVEL([>= '2.7'])
-# fi
-#
-# if test "x${cython_path}" = "x"; then
-#   AC_CHECK_PROGS([CYTHON], [cython.py cython])
-# else
-#   CYTHON=${cython_path}
-#   AC_SUBST([CYTHON])
-# fi
-
 #
 # If we're running GCC or clang define _U_ to be "__attribute__((unused))"
 # so we can use _U_ to flag unused function parameters and not get warnings
@@ -143,6 +131,18 @@ cmake_pop_check_state()
 # Additional libraries required for programs under src directory.
 set(APP_LIBRARIES)
 
+if(ENABLE_PYTHON_BINDINGS)
+  find_package(Cython         REQUIRED)
+  find_package(PythonLibs     REQUIRED)
+  if(NOT PYTHON_VERSION_STRING STREQUAL PYTHONLIBS_VERSION_STRING)
+    message(SEND_ERROR
+      "Python executable and library must have the same version!"
+      " Found Python ${PYTHON_VERSION_STRING} and"
+      " PythonLibs ${PYTHONLIBS_VERSION_STRING}"
+    )
+  endif()
+endif()
+
 set(CMAKE_THREAD_PREFER_PTHREAD 1)
 find_package(Threads)
 if(CMAKE_USE_PTHREADS_INIT)
@@ -311,16 +311,6 @@ else()
   set(HAVE_NEVERBLEED 0)
 endif()
 
-# Python bindings
-if(ENABLE_PYTHON_BINDINGS AND NOT CYTHON AND NOT PYTHONLIBS_FOUND)
-# XXX PythonInterp and PythonLibs are looked up before, unreachable check?
-# if test "x${request_python_bindings}" != "xno" &&
-#    test "x${CYTHON}" != "x" &&
-#    test "x${PYTHON}" != "x:" &&
-#    test "x${have_python_dev}" = "xyes"; then
-  message(FATAL_ERROR "python bindings were requested (ENABLE_PYTHON_BINDINGS=1) but dependencies are not met.")
-endif()
-
 # Checks for header files.
 # XXX AC_HEADER_ASSERT adds --disable-assert which sets -DNDEBUG
 include(CheckIncludeFile)
@@ -528,7 +518,6 @@ add_subdirectory(script)
 
 
 # XXX fix shared/static library
-# XXX fix python
 string(TOUPPER "${CMAKE_BUILD_TYPE}" _build_type)
 message(STATUS "summary of build options:
 
@@ -550,8 +539,7 @@ message(STATUS "summary of build options:
     Python:
       Python:         ${PYTHON_EXECUTABLE}
       PYTHON_VERSION: ${PYTHON_VERSION_STRING}
-      pyexecdir:      ${pyexecdir}
-      Python-dev:     ${have_python_dev}
+      Library version:${PYTHONLIBS_VERSION_STRING}
       Cython:         ${CYTHON_EXECUTABLE}
     Test:
       CUnit:          ${HAVE_CUNIT} (LIBS='${CUNIT_LIBRARIES}')

CMakeOptions.txt

@@ -23,7 +23,5 @@ option(WITH_SPDYLAY     "Use spdylay"
   ${WITH_SPDYLAY_DEFAULT})
 option(WITH_MRUBY       "Use mruby")
 option(WITH_NEVERBLEED  "Use neverbleed")
-set(CYTHON_PATH "" CACHE PATH     "Use cython in given path")
-set(CYTHON      "" CACHE FILEPATH "The Cython executable")
 
 # vim: ft=cmake:

cmake/FindCython.cmake

+# Find the Cython compiler.
+#
+# This code sets the following variables:
+#
+#  CYTHON_EXECUTABLE
+#
+# See also UseCython.cmake
+
+#=============================================================================
+# Copyright 2011 Kitware, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#=============================================================================
+
+# Use the Cython executable that lives next to the Python executable
+# if it is a local installation.
+find_package( PythonInterp )
+if( PYTHONINTERP_FOUND )
+  get_filename_component( _python_path ${PYTHON_EXECUTABLE} PATH )
+  find_program( CYTHON_EXECUTABLE
+    NAMES cython cython.bat cython3
+    HINTS ${_python_path}
+    )
+else()
+  find_program( CYTHON_EXECUTABLE
+    NAMES cython cython.bat cython3
+    )
+endif()
+
+
+include( FindPackageHandleStandardArgs )
+FIND_PACKAGE_HANDLE_STANDARD_ARGS( Cython REQUIRED_VARS CYTHON_EXECUTABLE )
+
+mark_as_advanced( CYTHON_EXECUTABLE )

python/CMakeLists.txt

 # EXTRA_DIST = cnghttp2.pxd nghttp2.pyx
 
-# XXX consider https://github.com/thewtex/cython-cmake-example
-
 if(ENABLE_PYTHON_BINDINGS)
-  # XXX add ALL? Will always be invoked as target is always out-of-date though.
-  add_custom_target(python
-    COMMAND ${PYTHON_EXECUTABLE} setup.py build
-    DEPENDS nghttp2.c
-  )
 
-  add_custom_target(python-install
-    COMMAND ${PYTHON_EXECUTABLE} setup.py install --prefix=${DESTDIR}${CMAKE_INSTALL_PREFIX}
+  add_custom_target(python ALL
+    COMMAND "${PYTHON_EXECUTABLE}" setup.py build
+    VERBATIM
+    DEPENDS nghttp2.c
   )
 
-  # XXX cmake does not have an uninstall target, do not bother with this then.
-  # XXX glob patterns like this will probably not work
-  #add_custom_target(python-uninstall
-  #  COMMAND ${CMAKE} -E remove -f ${DESTDIR}${CMAKE_INSTALL_FULL_LIBDIR}/python*/site-packages/nghttp2.so
-  #  COMMAND ${CMAKE} -E remove -f ${DESTDIR}${CMAKE_INSTALL_FULL_LIBDIR}/python*/site-packages/python_nghttp2-*.egg
-  #)
-
-  # XXX cleaner way to advertise the build artifacts? (note nghttp2.c is cleaned automatically)
-  add_custom_target(python-clean
-    COMMAND ${PYTHON_EXECUTABLE} setup.py clean --all
-  )
+  configure_file(install-python.cmake.in install-python.cmake ESCAPE_QUOTES @ONLY)
+  install(SCRIPT "${CMAKE_CURRENT_BINARY_DIR}/install-python.cmake")
 
-  # XXX CYTHON_EXECUTABLE is not set!
   add_custom_command(OUTPUT nghttp2.c
-    COMMAND ${CYTHON_EXECUTABLE} -o nghttp2.c nghttp2.pyx
+    COMMAND "${CYTHON_EXECUTABLE}" -o nghttp2.c
+      "${CMAKE_CURRENT_SOURCE_DIR}/nghttp2.pyx"
+    VERBATIM
     DEPENDS nghttp2.pyx
   )
+## This works also, except that the installation target is missing...
+#  include(UseCython)
+#  cython_add_module(python_nghttp2 nghttp2.pyx)
+#  set_target_properties(python_nghttp2 PROPERTIES
+#    OUTPUT_NAME nghttp2
+#  )
+#  target_include_directories(python_nghttp2 PRIVATE
+#    "${CMAKE_SOURCE_DIR}/lib"
+#    "${CMAKE_SOURCE_DIR}/lib/includes"
+#    "${CMAKE_BINARY_DIR}/lib/includes"
+#  )
+#  target_link_libraries(python_nghttp2
+#    nghttp2
+#  )
 endif()

python/install-python.cmake.in

+get_filename_component(rootdir "$ENV{DESTDIR}" ABSOLUTE)
+if(rootdir STREQUAL "")
+  set(rootdir /)
+endif()
+execute_process(
+  COMMAND "@PYTHON_EXECUTABLE@" setup.py install
+    --skip-build
+    --root=${rootdir} --prefix=${CMAKE_INSTALL_PREFIX}
+  WORKING_DIRECTORY "@CMAKE_CURRENT_BINARY_DIR@"
+)

python/setup.py.in

@@ -39,6 +39,7 @@ setup(
                                            '@top_srcdir@/lib/includes',
                                            '@top_builddir@/lib/includes'],
                              library_dirs=['@top_builddir@/lib/.libs',
+                                           '@top_builddir@/lib',
                                            '@top_builddir@'],
                              libraries=LIBS)],
     long_description='TBD'