app/django/contrib/gis/db/backend/util.py
author Lennard de Rijk <ljvderijk@gmail.com>
Fri, 23 Jan 2009 12:00:48 +0000
changeset 920 39badbfb80be
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Added the new way to process invites for club_admin only. This patch contains the separability needed to ensure that we can successfully do the access checks we need. Host invites can for the time being only be completed by developers due to the reorganization. Patch by: Lennard de Rijk Reviewed by: to-be-reviewed

from types import UnicodeType

def gqn(val):
    """
    The geographic quote name function; used for quoting tables and 
    geometries (they use single rather than the double quotes of the
    backend quotename function).
    """
    if isinstance(val, basestring):
        if isinstance(val, UnicodeType): val = val.encode('ascii')
        return "'%s'" % val
    else:
        return str(val)

class SpatialOperation(object):
    """
    Base class for generating spatial SQL.
    """
    def __init__(self, function='', operator='', result='', beg_subst='', end_subst=''):
        self.function = function
        self.operator = operator
        self.result = result
        self.beg_subst = beg_subst
        try:
            # Try and put the operator and result into to the
            # end substitution.
            self.end_subst = end_subst % (operator, result)
        except TypeError:
            self.end_subst = end_subst

    @property
    def sql_subst(self):
        return ''.join([self.beg_subst, self.end_subst])

    def as_sql(self, geo_col):
        return self.sql_subst % self.params(geo_col)

    def params(self, geo_col):
        return (geo_col, self.operator)

class SpatialFunction(SpatialOperation):
    """
    Base class for generating spatial SQL related to a function.
    """
    def __init__(self, func, beg_subst='%s(%s, %%s', end_subst=')', result='', operator=''):
        # Getting the function prefix.
        kwargs = {'function' : func, 'operator' : operator, 'result' : result,
                  'beg_subst' : beg_subst, 'end_subst' : end_subst,}
        super(SpatialFunction, self).__init__(**kwargs)

    def params(self, geo_col):
        return (self.function, geo_col)