cross_definitions.py

#!/bin/env python3
import os

###############################################################################


class CrossDefinitions():
    def __init__(
            self,
            name,
            description,
            binaries={},
            properties={},
            host_machine={},
            target_machine={},
            based_on=[]
         ):
        self.used = False
        self.name = name
        self.description = description

        self.sections_overlay = {
            'binaries':       binaries,
            'properties':     properties,
            'host_machine':   host_machine,
            'target_machine': target_machine,
        }
        self.sections_base = {
            'binaries':       {},
            'properties':     {},
            'host_machine':   {},
            'target_machine': {},
        }
        if based_on:
            if not isinstance(based_on, list):
                based_on = [based_on]
            for i in based_on:
                self.based_on(i)

    # Write to destdir/filename or filename
    def write_to_file(self, destdir=''):
        self.__apply_base()

        outfilepath = os.path.join(destdir, self.name + '.txt')
        os.makedirs(os.path.dirname(outfilepath) or '.', exist_ok=True)
        with open(outfilepath, 'w') as crossfile:

            # Write commented description
            crossfile.write(''.join([
                '# ' + i for i in self.description.splitlines(True)
            ]))
            crossfile.write('\n')

            # Write section and its variables
            def write_section(name, variables):
                crossfile.write('\n[{0}]\n'.format(name))
                maxnamelen = len(max(variables.keys(), key=len))
                for name, value in variables.items():
                    if value is not '':
                        crossfile.write('{0} = {1}\n'.format(
                            name.ljust(maxnamelen), repr(value)
                        ))

            # Write all sections, if not empty
            for name, values in self.sections_base.items():
                if values:
                    write_section(name, values)

    def merge_to_base(self, baselay, overlay):
        for section in overlay.keys():
            # Initialize as dict first…
            if section not in baselay:
                baselay[section] = {}

            # Replace scalars, merge lists
            for it in overlay[section].keys():
                if it in baselay[section] and \
                  (isinstance(overlay[section][it], list) or \
                   isinstance(baselay[section][it], list)):
                    baselay[section][it] = [
                        item for sublist in [
                            baselay[section][it], overlay[section][it],
                        ] for item in sublist
                    ]
                else:
                    baselay[section][it] = overlay[section][it]

    # Update as an overlay to base
    def based_on(self, base):
        if self.used:
            raise RuntimeError('Definitions ' + self.name + ' already used!')
        base.__apply_base()
        self.description += '\nBased on \'{0}\''.format(base.name)
        self.merge_to_base(self.sections_base, base.sections_base)

    def __apply_base(self):
        self.used = True
        self.merge_to_base(self.sections_base, self.sections_overlay)