[Following Mike's suggestion] Patch set for Postgresql pat1

gistfile1.txt

"""Add SP and trigger for CIDR overlap

Revision ID: cfbd4c516845
Revises: d3435b514502
Create Date: 2016-05-17 19:14:41.915533

"""
from alembic import op
from neutron.db.migration.alembic_migrations import replaceable_obj


# revision identifiers, used by Alembic.
revision = 'cfbd4c516845'
down_revision = 'd3435b514502'

add_stored_procedure_for_mysql = replaceable_obj.ReplaceableObject(
    "cidr_overlap(cidr1 varchar(30), cidr2 varchar(30))",
    """
    RETURNS TINYINT
    BEGIN
    DECLARE bitmask INT;
    SET bitmask = pow(
        2,
        (32 - least(
            cast(substring_index(cidr1, '/', -1) as signed integer),
            cast(substring_index(cidr2, '/', -1) as signed integer)
        ))
    ) - 1;

    RETURN
        inet_aton(substring_index(cidr1, '/', 1)) & ~bitmask =
        inet_aton(substring_index(cidr2, '/', 1)) & ~bitmask;
    END
    """
)

add_trigger_for_mysql = replaceable_obj.ReplaceableObject(
    "no_overlap_cidr_subnets",
    """
    BEFORE INSERT ON subnets
    FOR EACH ROW
    BEGIN
      DECLARE msg VARCHAR(200);
      IF (EXISTS(SELECT * FROM subnets WHERE network_id = NEW.network_id
        AND cidr_overlap(cidr, NEW.cidr))) THEN
        SET msg = CONCAT(
            'inserted subnet ', NEW.cidr,
            ' conflicts with existing subnets');
        SIGNAL sqlstate '45000'
            SET MESSAGE_TEXT = msg;
      END IF;
    END
    """
)

add_stored_procedure_1_for_postgresql = replaceable_obj.ReplaceableObject(
    "cidr_overlap (cidr1 CIDR, cidr2 CIDR)",
    """
    RETURNS BOOLEAN AS
    $$
    BEGIN
    RETURN
    (cidr1 <<= cidr2) OR (cidr2 <<= cidr1);
    END;
    $$ LANGUAGE plpgsql;
    """
)

add_operator_for_postgresql = replaceable_obj.ReplaceableObject(
    "&&",
    """
        (   PROCEDURE = cidr_overlap,
            LEFTARG = CIDR,
            RIGHTARG = CIDR,
            COMMUTATOR = &&,
            NEGATOR = !&&
        )
    """
)

add_operator_class_for_postgresql = replaceable_obj.ReplaceableObject(
    "custom_cidr_class FOR TYPE CIDR",
    """
    USING gist AS
    OPERATOR        3       &&
    """
)


def upgrade():
    if op.get_bind().engine.name == 'mysql':
        op.create_sp(add_stored_procedure_for_mysql)
        op.create_trigger(add_trigger_for_mysql)
    elif op.get_bind().engine.name == 'postgresql':
        op.create_sp(add_stored_procedure_1_for_postgresql)
        op.create_operator(add_operator_for_postgresql)
        op.create_operator_class(add_operator_class_for_postgresql)
    else:
        return