Source code for soma.application

# -*- coding: utf-8 -*-
__docformat__ = "restructuredtext en"


import os
import sys
import platform
import traceback
from os.path import dirname

os.environ['ETS_TOOLKIT'] = 'qt4'
from traits.api import ReadOnly, Directory, List, Instance

from soma.singleton import Singleton
from soma.controller import Controller

#-------------------------------------------------------------------------




class Application(Singleton, Controller):

    '''Any program using soma should create an Application instance to manage
    its configuration and to store any kind of value that have to be global to
    the program.'''
    name = ReadOnly(desc='Name of the application')
    version = ReadOnly()

    plugin_modules = List(str)(
        desc='List of Python module to load after application configuration')

    def __singleton_init__(self, name=None, version=None, *args, **kwargs):
        '''Replaces __init__ in Singleton.'''
        super(Application, self).__singleton_init__(*args, **kwargs)
        # Warning : Traits bug
        # Using the trait Directory() might instantiate a QApplication (seems to depend on the
        # traits release). If it is declared in the class, the QApplication is instantiated at
        # module importation which prevent to customize QApplication.
        self.add_trait('install_directory', Directory(
                       desc='Base directory where the application is installed'))
        self.add_trait('user_directory', Directory(
                       desc='Base directory where user specific information can be find'))
        self.add_trait('application_directory', Directory(
                       desc='Base directory where application specific information can be find'))
        self.add_trait('site_directory',  Directory(
                       desc='Base directory where site specific information can be find'))
        self._controller_factories = None

        if name is None:
            name = os.path.basename(sys.argv[0])
        self.name = name
        self.version = version
        self.loaded_plugin_modules = {}



    def initialize(self):
        '''This method must be called once to setup the application.'''
        if 'CASA_BUILD' in os.environ:
            self.install_directory = os.environ['CASA_BUILD']
        elif 'CONDA_PREFIX' in os.environ:
            self.install_directory = os.environ['CONDA_PREFIX']
        else:
            self.install_directory = dirname(dirname(dirname(__file__)))
        homedir = os.getenv('HOME')
        if not homedir:
            homedir = ''
            if platform.system() == 'Windows':
                homedir = os.getenv('USERPROFILE')
                if not homedir:
                    homedir = os.getenv('HOMEPATH')
                    if not homedir:
                        homedir = '\\'
                    drive = os.getenv('HOMEDRIVE')
                    if not drive:
                        drive = os.getenv('SystemDrive')
                        if not drive:
                            drive = os.getenv('SystemRoot')
                            if not drive:
                                drive = os.getenv('windir')
                            if drive and len(drive) >= 2:
                                drive = drive[:2]
                            else:
                                drive = ''
                    homedir = drive + homedir
        if homedir and os.path.exists(homedir):
            self.user_directory = homedir

        # Load early plugin modules
        for plugin_module in self.plugin_modules:
            module = self.load_plugin_module(plugin_module)
            if module is not None:
                self.loaded_plugin_modules[plugin_module] = module
                init = getattr(
                    module, 'call_before_application_initialization', None)
                if init is not None:
                    init(self)

        appdir = os.path.normpath(
            os.path.dirname(os.path.dirname(sys.argv[0])))
        if os.path.exists(appdir):
            self.application_directory = appdir

        sitedir = os.path.join('/etc', self.name)
        if os.path.exists(sitedir):
            self.site_directory = sitedir

        # Load plugin modules
        for plugin_module in self.plugin_modules:
            module = self.loaded_plugin_modules.get(plugin_module)
            if module is None:
                module = self.load_plugin_module(plugin_module)
            if module is not None:
                self.loaded_plugin_modules[plugin_module] = module
                init = getattr(
                    module, 'call_after_application_initialization', None)
                if init is not None:
                    init(self)




    @staticmethod
    def load_plugin_module(plugin_module):
        '''This method loads a plugin module. It imports the module without raising
        an exception if it fails.'''
        try:
            __import__(plugin_module, level=0)
            return sys.modules[plugin_module]
        except Exception:
            # Python 2.6 hack : print_last may fail here (maybe due to threads management)
            # traceback.print_last()
            exceptionType, exceptionValue, exceptionTraceback = sys.exc_info()
            traceback.print_exception(
                exceptionType, exceptionValue, exceptionTraceback)
        return None