Add ability of compile our python installation files into (.pyc/.pyo) depending on our python version

Because this way the initialization of our apk it will be faster. We must use the .pyc extension for our python 3 because as of Python 3.5, the .pyo filename extension is no longer used and has been removed. Notice that the command to compile the files for python 3 is slightly different (`-b` option added). This is done that way because otherwise our compiled files would be put in `__pycache__` folder and this option makes that the compiled files gets putted in the same directory than the compiled file.

See also:
  - `PEP 488 -- Elimination of PYO files` (https://www.python.org/dev/peps/pep-0488/)
  - `PEP 3147 -- PYC Repository Directories` as to why a separate directory is used (https://www.python.org/dev/peps/pep-3147/)

Author: opacam

pythonforandroid/python.py

@@ -6,6 +6,7 @@
 from os.path import dirname, exists, join
 from shutil import copy2
 from os import environ
+import subprocess
 import glob
 import sh
 
@@ -71,7 +72,7 @@ class GuestPythonRecipe(TargetPythonRecipe):
     '''The directories that we want to omit for our python bundle'''
 
     stdlib_filen_blacklist = [
-        '*.pyc',
+        '*.py',
         '*.exe',
         '*.whl',
     ]
@@ -84,13 +85,23 @@ class GuestPythonRecipe(TargetPythonRecipe):
     '''The directories from site packages dir that we don't want to be included
     in our python bundle.'''
 
-    site_packages_filen_blacklist = []
+    site_packages_filen_blacklist = [
+        '*.py'
+    ]
     '''The file extensions from site packages dir that we don't want to be
     included in our python bundle.'''
 
     opt_depends = ['sqlite3', 'libffi', 'openssl']
     '''The optional libraries which we would like to get our python linked'''
 
+    compiled_extension = '.pyc'
+    '''the default extension for compiled python files.
+
+    .. note:: the default extension for compiled python files has been .pyo for
+        python 2.x-3.4 but as of Python 3.5, the .pyo filename extension is no
+        longer used and has been removed in favour of extension .pyc
+    '''
+
     def __init__(self, *args, **kwargs):
         self._ctx = None
         super(GuestPythonRecipe, self).__init__(*args, **kwargs)
@@ -249,26 +260,48 @@ def include_root(self, arch_name):
     def link_root(self, arch_name):
         return join(self.get_build_dir(arch_name), 'android-build')
 
+    def compile_python_files(self, dir):
+        '''
+        Compile the python files (recursively) for the python files inside
+        a given folder.
+
+        .. note:: python2 compiles the files into extension .pyo, but in
+            python3, and as of Python 3.5, the .pyo filename extension is no
+            longer used...uses .pyc (https://www.python.org/dev/peps/pep-0488)
+        '''
+        args = [self.ctx.hostpython]
+        # Todo: make dynamic `-OO`, strip docstrings, via `--no-optimize-python`
+        if self.ctx.python_recipe.name == 'python3':
+            args += ['-OO', '-m', 'compileall', '-b', '-f', dir]
+        else:
+            args += ['-OO', '-m', 'compileall', '-f', dir]
+        subprocess.call(args)
+
     def create_python_bundle(self, dirn, arch):
         """
         Create a packaged python bundle in the target directory, by
         copying all the modules and standard library to the right
         place.
         """
+        # Todo: find a better way to find the build libs folder
+        modules_build_dir = join(
+            self.get_build_dir(arch.arch), 'android-build', 'build',
+            'lib.linux{}-arm-{}'.format('2' if self.version[0] == '2' else '',
+                                        self.major_minor_version_string))
+
+        # Compile to *.pyc/*.pyo the python modules
+        self.compile_python_files(modules_build_dir)
+        # Compile to *.pyc/*.pyo the standard python library
+        self.compile_python_files(join(self.get_build_dir(arch.arch), 'Lib'))
+        # Compile to *.pyc/*.pyo the other python packages (site-packages)
+        self.compile_python_files(self.ctx.get_python_install_dir())
+
         # Bundle compiled python modules to a folder
         modules_dir = join(dirn, 'modules')
+        c_ext = self.compiled_extension
         ensure_dir(modules_dir)
-        # Todo: find a better way to find the build libs folder
-        modules_build_dir = join(
-            self.get_build_dir(arch.arch),
-            'android-build',
-            'build',
-            'lib.linux{}-arm-{}'.format(
-                '2' if self.version[0] == '2' else '',
-                self.major_minor_version_string
-            ))
         module_filens = (glob.glob(join(modules_build_dir, '*.so')) +
-                         glob.glob(join(modules_build_dir, '*.py')))
+                         glob.glob(join(modules_build_dir, '*' + c_ext)))
         info("Copy {} files into the bundle".format(len(module_filens)))
         for filen in module_filens:
             info(" - copy {}".format(filen))

pythonforandroid/recipes/python2/__init__.py

@@ -47,6 +47,8 @@ class Python2Recipe(GuestPythonRecipe):
                       '--prefix={prefix}',
                       '--exec-prefix={exec_prefix}')
 
+    compiled_extension = '.pyo'
+
     def prebuild_arch(self, arch):
         super(Python2Recipe, self).prebuild_arch(arch)
         patch_mark = join(self.get_build_dir(arch.arch), '.openssl-patched')