| [976] | 1 | ###
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| 2 | ### IDCache - Cache for fast id lookups to an SQL table
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| 3 | ###
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| 4 |
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| 5 | from ...builtins import *
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| 6 | from ...parsing.autotype import *
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| 7 |
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| 8 | class IDCache(object):
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| 9 |
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| 10 | def __init__(self, conn=None, cache=None, static=False, table=None, key_column=None, value_column=None, anchors=None, extras=None, initialize=True, init_append=None):
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| 11 |
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| 12 | self.conn = conn
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| 13 | self.table = table
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| 14 | self.key_column = key_column
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| 15 | self.value_column = value_column
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| 16 | self.anchors = anchors
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| 17 | self.extras = extras
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| 18 |
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| 19 | if cache is None:
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| 20 | self.cache = {}
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| 21 | else:
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| 22 | self.cache = cache
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| 23 |
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| 24 | self.static = static
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| 25 |
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| 26 | init_sql = "SELECT %s, %s FROM %s" % (key_column, value_column, table)
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| 27 | anchor_sql = ""
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| 28 |
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| 29 | if anchors:
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| 30 |
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| 31 | i = 0
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| 32 |
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| 33 | for key, value in anchors.items():
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| 34 |
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| 35 | if i == 0:
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| 36 | init_sql = '%s WHERE ' % (init_sql)
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| 37 | else:
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| 38 | init_sql = '%s AND ' % (init_sql)
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| 39 |
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| 40 | if type(value) in (int, float):
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| 41 | init_sql = "%s %s = %s" % (init_sql, key, value)
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| 42 | anchor_sql = "%s AND %s = %s" % (anchor_sql, key, value)
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| 43 | else:
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| 44 | init_sql = "%s %s = '%s'" % (init_sql, key, value)
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| 45 | anchor_sql = "%s AND %s = '%s'" % (anchor_sql, key, value)
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| 46 |
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| 47 | i += 1
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| 48 |
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| 49 | if init_append:
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| 50 | self.init_sql = '%s %s' % (init_sql, init_append)
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| 51 | else:
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| 52 | self.init_sql = '%s' % (init_sql)
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| 53 |
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| 54 | self.anchor_sql = anchor_sql
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| 55 |
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| 56 | if initialize:
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| 57 | self.initialize()
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| 58 |
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| 59 | #
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| 60 | # initilize the cache
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| 61 | #
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| 62 | def initialize(self):
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| 63 |
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| 64 | cache = self.cache
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| 65 | key_column = self.key_column
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| 66 | value_column = self.value_column
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| 67 | table = self.table
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| 68 | anchors = self.anchors
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| 69 | curs = self.conn.cursor()
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| 70 |
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| 71 | sql = self.init_sql
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| 72 |
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| 73 | for row in curs.execute(sql):
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| 74 | cache[row[key_column]] = row[value_column]
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| 75 |
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| 76 | #
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| 77 | # flush the cache
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| 78 | #
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| 79 | def flush(self):
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| 80 | self.cache = {}
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| 81 |
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| 82 | #
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| 83 | # return a value
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| 84 | #
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| 85 | def __getitem__(self, key):
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| 86 |
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| 87 | cache = self.cache
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| 88 | anchors = self.anchors
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| 89 | anchor_sql = self.anchor_sql
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| 90 |
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| 91 | if key in cache.keys():
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| 92 | return cache[key]
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| 93 | elif not self.static:
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| 94 | key_column = self.key_column
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| 95 | value_column = self.value_column
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| 96 | table = self.table
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| 97 | curs = self.conn.cursor()
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| 98 | sql = "SELECT %s FROM %s WHERE %s = '%s'%s" % (value_column, self.table, self.key_column, key, anchor_sql)
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| 99 | curs.execute(sql)
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| 100 | results = curs.fetchone()
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| 101 | if results:
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| 102 | value = results[0]
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| 103 | cache[key] = value
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| 104 | return value
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| 105 | else:
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| 106 | return None
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| 107 | else:
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| 108 | return None
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| 109 |
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| 110 | #
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| 111 | # set a value
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| 112 | #
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| 113 | def __setitem__(self, key, value):
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| 114 |
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| 115 | cache = self.cache
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| 116 |
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| 117 | cache[key] = value
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| 118 |
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| 119 | #
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| 120 | # delete a value
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| 121 | #
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| 122 | def __delitem__(self, key):
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| 123 |
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| 124 | cache = self.cache
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| 125 |
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| 126 | if cache.has_key(key):
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| 127 | del cache[key]
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| 128 |
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| 129 | #
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| 130 | #
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| 131 | #
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| 132 | def __contains__(self, item):
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| 133 |
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| 134 | cache = self.cache
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| 135 |
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| 136 | if cache.has_key(item):
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| 137 | return True
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| 138 | else:
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| 139 | return False
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| 140 |
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| 141 | #
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| 142 | #
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| 143 | #
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| 144 | def has_key(self, key):
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| 145 |
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| 146 | return key in self
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| 147 |
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| 148 | #
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| 149 | #
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| 150 | #
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| 151 | def keys(self):
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| 152 |
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| 153 | cache = self.cache
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| 154 |
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| 155 | return cache.keys()
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| 156 |
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| 157 | #
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| 158 | #
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| 159 | #
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| 160 | def __iter__(self):
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| 161 |
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| 162 | return iter(self.keys())
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| 163 |
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| 164 | #
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| 165 | # actions to take when an IDCache is deleted
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| 166 | #
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| 167 | def __del__(self):
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| 168 |
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| 169 | cache = self.cache
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| 170 |
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| 171 | if hasattr(cache, 'close'):
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| 172 | cache.close()
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| 173 |
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