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'''$Id: db.py,v 1.31.2.7 2004/07/01 21:31:58 fog Exp $'''
__version__='$Revision: 1.31.2.7 $'[11:-2]


from Shared.DC.ZRDB.TM import TM
from Shared.DC.ZRDB import dbi_db

import string, sys
from string import strip, split, find
from time import time
from types import ListType
import site

import psycopg
from psycopg import NUMBER, STRING, INTEGER, FLOAT, DATETIME
from psycopg import BOOLEAN, ROWID, LONGINTEGER
from ZODB.POSException import ConflictError

class DB(TM,dbi_db.DB):

    _p_oid = _p_changed = _registered = None

    def __init__(self, connection, tilevel, enc='utf-8'):
        self.connection = connection
        self.tilevel = tilevel
        self.encoding = enc 
        self.db = self.connect(self.connection)
        self.failures = 0
        self.calls = 0

    def connect(self, connection):
        o = psycopg.connect(connection)
        o.set_isolation_level(int(self.tilevel))
        return o
    
    def _finish(self, *ignored):
        if hasattr(self, 'db') and self.db:
            self.db.commit()
            
    def _abort(self, *ignored):
        if hasattr(self, 'db') and self.db:
            self.db.rollback()
            
    def _cursor(self):
        """Obtains a cursor in a safe way."""
        if not hasattr(self, 'db') or not self.db:
            self.db = self.connect(self.connection)
        return self.db.cursor()
    
    def tables(self, rdb=0, _care=('TABLE', 'VIEW')):
        self._register()
        c = self._cursor()
        c.execute('SELECT t.tablename AS NAME, '
                  '\'TABLE\' AS TYPE FROM pg_tables t '
                  'WHERE tableowner <> \'postgres\' '
                  'UNION SELECT v.viewname AS NAME, '
                  '\'VIEW\' AS TYPE FROM pg_views v '
                  'WHERE viewowner <> \'postgres\' '
                  'UNION SELECT t.tablename AS NAME, '
                  '\'SYSTEM_TABLE\' AS TYPE FROM pg_tables t '
                  'WHERE tableowner = \'postgres\' '
                  'UNION SELECT v.viewname AS NAME, '
                  '\'SYSTEM_TABLE\' AS TYPE FROM pg_views v '
                  'WHERE viewowner = \'postgres\' ' )
        r = []
        a = r.append
        for name, typ in c.fetchall():
            if typ in _care:
                a({'TABLE_NAME': name, 'TABLE_TYPE': typ})
        c.close()
        return r

    def columns(self, table_name):
        self._register()
        c = self._cursor()
        try:
            r = c.execute('select * from "%s" where 1=0' % table_name)
        except:
            return ()
        desc = c.description
        r = []
        a = r.append
        for name, type, width, ds, p, scale, null_ok in desc:
            if type == NUMBER:
                if type == INTEGER:
                    type = INTEGER
                elif type == FLOAT:
                    type = FLOAT
                else: type = NUMBER
            elif type == BOOLEAN:
                type = BOOLEAN
            elif type == ROWID:
                type = ROWID
            elif type == DATETIME:
                type = DATETIME
            else:
                type = STRING
            a({ 'Name': name,
                'Type': type.name,
                'Precision': 0,
                'Scale': 0,
                'Nullable': 0})
        return r

    def query(self, query_string, max_rows=None, query_data=None):
        self._register()
        self.calls = self.calls+1
        
        desc = ()
        result = []
        nselects = 0
        
        c = self._cursor()
        
        try:
            for qs in filter(None, map(strip, split(query_string, '\0'))):
                if type(qs) == unicode:
                    if self.encoding:
                        qs = qs.encode(self.encoding)
                try:
                    if (query_data):
                        r = c.execute(qs, query_data)
                    else:
                        r = c.execute(qs)
                except (psycopg.ProgrammingError,psycopg.IntegrityError), perr:
                    if perr.args[0].find("concurrent update") > -1:
                        raise ConflictError
                    raise perr
                if c.description is not None:
                    nselects = nselects + 1
                    if c.description != desc and nselects > 1:
                        raise 'Query Error', \
                              'Multiple select schema are not allowed'
                    if max_rows:
                        result = c.fetchmany(max_rows)
                    else:
                        result = c.fetchall()
                    desc = c.description
            self.failures = 0
            
        except StandardError, err:
            self._abort()
            raise err
        
        items = []
        for name, typ, width, ds, p, scale, null_ok in desc:
            if typ == NUMBER:
                if typ == INTEGER or typ == LONGINTEGER: typs = 'i'
                else: typs = 'n'
            elif typ == BOOLEAN:
                typs = 'n'
            elif typ == ROWID:
                typs = 'i'
            elif typ == DATETIME:
                typs = 'd'
            else:
                typs = 's'
            items.append({
                'name': name,
                'type': typs,
                'width': width,
                'null': null_ok,
                })

        return items, result

    def close(self):
        """Close the connection."""
        self.db.close()
        self.db = None
        
    def sortKey(self):
        """Zope 2.6 added this one."""
        return 1
