Mini Shell

"""
Peewee integration with APSW, "another python sqlite wrapper".

Project page: https://rogerbinns.github.io/apsw/

APSW is a really neat library that provides a thin wrapper on top of SQLite's
C interface.

Here are just a few reasons to use APSW, taken from the documentation:

* APSW gives all functionality of SQLite, including virtual tables, virtual
  file system, blob i/o, backups and file control.
* Connections can be shared across threads without any additional locking.
* Transactions are managed explicitly by your code.
* APSW can handle nested transactions.
* Unicode is handled correctly.
* APSW is faster.
"""
import apsw
from peewee import *
from peewee import __exception_wrapper__
from peewee import BooleanField as _BooleanField
from peewee import DateField as _DateField
from peewee import DateTimeField as _DateTimeField
from peewee import DecimalField as _DecimalField
from peewee import Insert
from peewee import TimeField as _TimeField
from peewee import logger

from playhouse.sqlite_ext import SqliteExtDatabase


class APSWDatabase(SqliteExtDatabase):
    server_version = tuple(int(i) for i in apsw.sqlitelibversion().split('.'))

    def __init__(self, database, **kwargs):
        self._modules = {}
        super(APSWDatabase, self).__init__(database, **kwargs)

    def register_module(self, mod_name, mod_inst):
        self._modules[mod_name] = mod_inst
        if not self.is_closed():
            self.connection().createmodule(mod_name, mod_inst)

    def unregister_module(self, mod_name):
        del(self._modules[mod_name])

    def _connect(self):
        conn = apsw.Connection(self.database, **self.connect_params)
        if self._timeout is not None:
            conn.setbusytimeout(self._timeout * 1000)
        try:
            self._add_conn_hooks(conn)
        except:
            conn.close()
            raise
        return conn

    def _add_conn_hooks(self, conn):
        super(APSWDatabase, self)._add_conn_hooks(conn)
        self._load_modules(conn)  # APSW-only.

    def _load_modules(self, conn):
        for mod_name, mod_inst in self._modules.items():
            conn.createmodule(mod_name, mod_inst)
        return conn

    def _load_aggregates(self, conn):
        for name, (klass, num_params) in self._aggregates.items():
            def make_aggregate():
                return (klass(), klass.step, klass.finalize)
            conn.createaggregatefunction(name, make_aggregate)

    def _load_collations(self, conn):
        for name, fn in self._collations.items():
            conn.createcollation(name, fn)

    def _load_functions(self, conn):
        for name, (fn, num_params) in self._functions.items():
            conn.createscalarfunction(name, fn, num_params)

    def _load_extensions(self, conn):
        conn.enableloadextension(True)
        for extension in self._extensions:
            conn.loadextension(extension)

    def load_extension(self, extension):
        self._extensions.add(extension)
        if not self.is_closed():
            conn = self.connection()
            conn.enableloadextension(True)
            conn.loadextension(extension)

    def last_insert_id(self, cursor, query_type=None):
        if not self.returning_clause:
            return cursor.getconnection().last_insert_rowid()
        elif query_type == Insert.SIMPLE:
            try:
                return cursor[0][0]
            except (AttributeError, IndexError, TypeError):
                pass
        return cursor

    def rows_affected(self, cursor):
        try:
            return cursor.getconnection().changes()
        except AttributeError:
            return cursor.cursor.getconnection().changes()  # RETURNING query.

    def begin(self, lock_type='deferred'):
        self.cursor().execute('begin %s;' % lock_type)

    def commit(self):
        with __exception_wrapper__:
            curs = self.cursor()
            if curs.getconnection().getautocommit():
                return False
            curs.execute('commit;')
        return True

    def rollback(self):
        with __exception_wrapper__:
            curs = self.cursor()
            if curs.getconnection().getautocommit():
                return False
            curs.execute('rollback;')
        return True

    def execute_sql(self, sql, params=None):
        logger.debug((sql, params))
        with __exception_wrapper__:
            cursor = self.cursor()
            cursor.execute(sql, params or ())
        return cursor


def nh(s, v):
    if v is not None:
        return str(v)

class BooleanField(_BooleanField):
    def db_value(self, v):
        v = super(BooleanField, self).db_value(v)
        if v is not None:
            return v and 1 or 0

class DateField(_DateField):
    db_value = nh

class TimeField(_TimeField):
    db_value = nh

class DateTimeField(_DateTimeField):
    db_value = nh

class DecimalField(_DecimalField):
    db_value = nh