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'''$Id: db.py,v 1.20 2002/03/14 20:24:54 adustman Exp $'''
__version__='$Revision: 1.20 $'[11:-2]

import _mysql
import MySQLdb
from _mysql_exceptions import OperationalError, NotSupportedError
MySQLdb_version_required = (0,9,2)

_v = getattr(_mysql, 'version_info', (0,0,0))
if _v < MySQLdb_version_required:
    raise NotSupportedError, \
	"ZMySQLDA requires at least MySQLdb %s, %s found" % \
	(MySQLdb_version_required, _v)

from MySQLdb.converters import conversions
from MySQLdb.constants import FIELD_TYPE, CR, CLIENT
from Shared.DC.ZRDB.TM import TM
from DateTime import DateTime
from zLOG import LOG, ERROR, INFO

import string, sys
from string import strip, split, find, upper, rfind
from time import time
from thread import get_ident, allocate_lock

hosed_connection = (
    CR.SERVER_GONE_ERROR,
    CR.SERVER_LOST
    )

key_types = {
    "PRI": "PRIMARY KEY",
    "MUL": "INDEX",
    "UNI": "UNIQUE",
    }

field_icons = "bin", "date", "datetime", "float", "int", "text", "time"

icon_xlate = {
    "varchar": "text", "char": "text",
    "enum": "what", "set": "what",
    "double": "float", "numeric": "float",
    "blob": "bin", "mediumblob": "bin", "longblob": "bin",
    "tinytext": "text", "mediumtext": "text",
    "longtext": "text", "timestamp": "datetime",
    "decimal": "float", "smallint": "int",
    "mediumint": "int", "bigint": "int",
    }

type_xlate = {
    "double": "float", "numeric": "float",
    "decimal": "float", "smallint": "int",
    "mediumint": "int", "bigint": "int",
    "int": "int", "float": "float",
    "timestamp": "datetime", "datetime": "datetime",
    "time": "datetime",
    }
    
def _mysql_timestamp_converter(s):
	if len(s) < 14:
		s = s + "0"*(14-len(s))
        parts = map(int, (s[:4],s[4:6],s[6:8],
                          s[8:10],s[10:12],s[12:14]))
	return DateTime("%04d-%02d-%02d %02d:%02d:%02d" % tuple(parts))

def DateTime_or_None(s):
    try: return DateTime(s)
    except: return None

def int_or_long(s):
    try: return int(s)
    except: return long(s)

class ThreadedDB:
    """
      This class is an interface to DB.
      Its caracteristic is that an instance of this class interfaces multiple
      instanes of DB class, each one being bound to a specific thread.
    """

    conv=conversions.copy()
    conv[FIELD_TYPE.LONG] = int_or_long
    conv[FIELD_TYPE.DATETIME] = DateTime_or_None
    conv[FIELD_TYPE.DATE] = DateTime_or_None
    conv[FIELD_TYPE.DECIMAL] = float
    del conv[FIELD_TYPE.TIME]

    def __init__(self,connection):
        """
          Parse the connection string.
          Initiate a trial connection with the database to check
          transactionality once instead of once per DB instance.
        """
        self._connection = connection
        self._kw_args = self._parse_connection_string(connection)
        self._db_pool = {}
        self._db_lock = allocate_lock()
        connection = MySQLdb.connect(**self._kw_args)
        transactional = connection.server_capabilities & CLIENT.TRANSACTIONS
        connection.close()
        if self._try_transactions == '-':
            transactional = 0
        elif not transactional and self._try_transactions == '+':
            raise NotSupportedError, "transactions not supported by this server"
        self._use_TM = self._transactions = transactional
        if self._mysql_lock:
            self._use_TM = 1

    def _parse_connection_string(self, connection):
        kwargs = {'conv': self.conv}
        items = split(connection)
        self._use_TM = None
        if not items: return kwargs
        lockreq, items = items[0], items[1:]
        if lockreq[0] == "*":
            self._mysql_lock = lockreq[1:]
            db_host, items = items[0], items[1:]
            self._use_TM = 1
        else:
            self._mysql_lock = None
            db_host = lockreq
        if '@' in db_host:
            db, host = split(db_host,'@',1)
            kwargs['db'] = db
            if ':' in host:
                host, port = split(host,':',1)
                kwargs['port'] = int(port)
            kwargs['host'] = host
        else:
            kwargs['db'] = db_host
        if kwargs['db'] and kwargs['db'][0] in ('+', '-'):
            self._try_transactions = kwargs['db'][0]
            kwargs['db'] = kwargs['db'][1:]
        else:
            self._try_transactions = None
        if not kwargs['db']:
            del kwargs['db']
        if not items: return kwargs
        kwargs['user'], items = items[0], items[1:]
        if not items: return kwargs
        kwargs['passwd'], items = items[0], items[1:]
        if not items: return kwargs
        kwargs['unix_socket'], items = items[0], items[1:]
        return kwargs

    def _pool_set(self, key, value):
      self._db_lock.acquire()
      try:
        self._db_pool[key] = value
      finally:
        self._db_lock.release()

    def _pool_get(self, key):
      self._db_lock.acquire()
      try:
        return self._db_pool.get(key)
      finally:
        self._db_lock.release()

    def _access_db(self, method_id, args, kw):
        """
          Generic method to call pooled objects' methods.
          When the current thread had never issued any call, create a DB
          instance.
        """
        ident = get_ident()
        db = self._pool_get(ident)
        if db is None:
            db = DB(kw_args=self._kw_args, use_TM=self._use_TM,
                    mysql_lock=self._mysql_lock,
                    transactions=self._transactions)
            self._pool_set(ident, db)
        return getattr(db, method_id)(*args, **kw)

    def tables(self, *args, **kw):
        return self._access_db(method_id='tables', args=args, kw=kw)

    def columns(self, *args, **kw):
        return self._access_db(method_id='columns', args=args, kw=kw)

    def query(self, *args, **kw):
        return self._access_db(method_id='query', args=args, kw=kw)

    def string_literal(self, *args, **kw):
        return self._access_db(method_id='string_literal', args=args, kw=kw)

class DB(TM):

    defs={
        FIELD_TYPE.CHAR: "i", FIELD_TYPE.DATE: "d",
        FIELD_TYPE.DATETIME: "d", FIELD_TYPE.DECIMAL: "n",
        FIELD_TYPE.DOUBLE: "n", FIELD_TYPE.FLOAT: "n", FIELD_TYPE.INT24: "i",
        FIELD_TYPE.LONG: "i", FIELD_TYPE.LONGLONG: "l",
        FIELD_TYPE.SHORT: "i", FIELD_TYPE.TIMESTAMP: "d",
        FIELD_TYPE.TINY: "i", FIELD_TYPE.YEAR: "i",
        }

    _p_oid=_p_changed=_registered=None

    def __init__(self, kw_args, use_TM, mysql_lock, transactions):
        self._kw_args = kw_args
        self._mysql_lock = mysql_lock
        self._use_TM = use_TM
        self._transactions = transactions
        self._forceReconnection()

    def __del__(self):
      self.db.close()

    def _forceReconnection(self):
      db = MySQLdb.connect(**self._kw_args)
      self.db = db

    def tables(self, rdb=0,
               _care=('TABLE', 'VIEW')):
        r=[]
        a=r.append
        result = self._query("SHOW TABLES")
        row = result.fetch_row(1)
        while row:
            a({'TABLE_NAME': row[0][0], 'TABLE_TYPE': 'TABLE'})
            row = result.fetch_row(1)
        return r

    def columns(self, table_name):
        from string import join
        try:
            c = self._query('SHOW COLUMNS FROM %s' % table_name)
        except:
            return ()
        r=[]
        for Field, Type, Null, Key, Default, Extra in c.fetch_row(0):
            info = {}
            field_default = Default and "DEFAULT %s"%Default or ''
            if Default: info['Default'] = Default
            if '(' in Type:
                end = rfind(Type,')')
                short_type, size = split(Type[:end],'(',1)
                if short_type not in ('set','enum'):
                    if ',' in size:
                        info['Scale'], info['Precision'] = \
                                       map(int, split(size,',',1))
                    else:
                        info['Scale'] = int(size)
            else:
                short_type = Type
            if short_type in field_icons:
                info['Icon'] = short_type
            else:
                info['Icon'] = icon_xlate.get(short_type, "what")
            info['Name'] = Field
            info['Type'] = type_xlate.get(short_type,'string')
            info['Extra'] = Extra,
            info['Description'] = join([Type, field_default, Extra or '',
                                        key_types.get(Key, Key or ''),
                                        Null != 'YES' and 'NOT NULL' or '']),
            info['Nullable'] = (Null == 'YES') and 1 or 0
            if Key:
                info['Index'] = 1
            if Key == 'PRI':
                info['PrimaryKey'] = 1
                info['Unique'] = 1
            elif Key == 'UNI':
                info['Unique'] = 1
            r.append(info)
        return r

    def _query(self, query, force_reconnect=False):
        """
          Send a query to MySQL server.
          It reconnects automaticaly if needed and the following conditions are
          met:
           - It has not just tried to reconnect (ie, this function will not
             attemp to connect twice per call).
           - This conection is not transactionnal and has set not MySQL locks,
             because they are bound to the connection. This check can be
             overridden by passing force_reconnect with True value.
        """
        try:
            self.db.query(query)
        except OperationalError, m:
            if ((not force_reconnect) and \
                (self._mysql_lock or self._transactions)) or \
               m[0] not in hosed_connection:
                raise
            # Hm. maybe the db is hosed.  Let's restart it.
            self._forceReconnection()
            self.db.query(query)
        return self.db.store_result()

    def query(self,query_string, max_rows=1000):
        self._use_TM and self._register()
        desc=None
        result=()
        for qs in filter(None, map(strip,split(query_string, '\0'))):
            qtype = upper(split(qs, None, 1)[0])
            if qtype == "SELECT" and max_rows:
                qs = "%s LIMIT %d" % (qs,max_rows)
                r=0
            c = self._query(qs)
            if desc is not None:
                if c and (c.describe() != desc):
                    raise 'Query Error', (
                        'Multiple select schema are not allowed'
                        )
            if c:
                desc=c.describe()
                result=c.fetch_row(max_rows)
            else:
                desc=None

        if desc is None: return (),()

        items=[]
        func=items.append
        defs=self.defs
        for d in desc:
            item={'name': d[0],
                  'type': defs.get(d[1],"t"),
                  'width': d[2],
                  'null': d[6]
                 }
            func(item)
        return items, result

    def string_literal(self, s):
        return self.db.string_literal(s)

    def _begin(self, *ignored):
        try:
            self._transaction_begun = True
            # Ping the database to reconnect if connection was closed.
            self._query("SELECT 1", force_reconnect=True)
            if self._transactions:
                self._query("BEGIN")
            if self._mysql_lock:
                self._query("SELECT GET_LOCK('%s',0)" % self._mysql_lock)
        except:
            LOG('ZMySQLDA', ERROR, "exception during _begin",
                error=sys.exc_info())
            raise

    def _finish(self, *ignored):
        if not self._transaction_begun:
            return
        self._transaction_begun = False
        if self._mysql_lock:
            self._query("SELECT RELEASE_LOCK('%s')" % self._mysql_lock)
        if self._transactions:
            self._query("COMMIT")

    def _abort(self, *ignored):
        if not self._transaction_begun:
            return
        self._transaction_begun = False
        if self._mysql_lock:
            self._query("SELECT RELEASE_LOCK('%s')" % self._mysql_lock)
        if self._transactions:
            self._query("ROLLBACK")
        else:
            LOG('ZMySQLDA', ERROR, "aborting when non-transactional")

