Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/util.py: 19%

1# engine/util.py 

2# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors 

3# <see AUTHORS file> 

4# 

5# This module is part of SQLAlchemy and is released under 

6# the MIT License: https://www.opensource.org/licenses/mit-license.php 

7 

8from .. import exc 

9from .. import util 

10from ..util import collections_abc 

11from ..util import immutabledict 

12 

13 

14def connection_memoize(key): 

15 """Decorator, memoize a function in a connection.info stash. 

16 

17 Only applicable to functions which take no arguments other than a 

18 connection. The memo will be stored in ``connection.info[key]``. 

19 """ 

20 

21 @util.decorator 

22 def decorated(fn, self, connection): 

23 connection = connection.connect() 

24 try: 

25 return connection.info[key] 

26 except KeyError: 

27 connection.info[key] = val = fn(self, connection) 

28 return val 

29 

30 return decorated 

31 

32 

33_no_tuple = () 

34_no_kw = util.immutabledict() 

35 

36 

37def _distill_params(connection, multiparams, params): 

38 r"""Given arguments from the calling form \*multiparams, \**params, 

39 return a list of bind parameter structures, usually a list of 

40 dictionaries. 

41 

42 In the case of 'raw' execution which accepts positional parameters, 

43 it may be a list of tuples or lists. 

44 

45 """ 

46 

47 if not multiparams: 

48 if params: 

49 connection._warn_for_legacy_exec_format() 

50 return [params] 

51 else: 

52 return [] 

53 elif len(multiparams) == 1: 

54 zero = multiparams[0] 

55 if isinstance(zero, (list, tuple)): 

56 if ( 

57 not zero 

58 or hasattr(zero[0], "__iter__") 

59 and not hasattr(zero[0], "strip") 

60 ): 

61 # execute(stmt, [{}, {}, {}, ...]) 

62 # execute(stmt, [(), (), (), ...]) 

63 return zero 

64 else: 

65 # this is used by exec_driver_sql only, so a deprecation 

66 # warning would already be coming from passing a plain 

67 # textual statement with positional parameters to 

68 # execute(). 

69 # execute(stmt, ("value", "value")) 

70 return [zero] 

71 elif hasattr(zero, "keys"): 

72 # execute(stmt, {"key":"value"}) 

73 return [zero] 

74 else: 

75 connection._warn_for_legacy_exec_format() 

76 # execute(stmt, "value") 

77 return [[zero]] 

78 else: 

79 connection._warn_for_legacy_exec_format() 

80 if hasattr(multiparams[0], "__iter__") and not hasattr( 

81 multiparams[0], "strip" 

82 ): 

83 return multiparams 

84 else: 

85 return [multiparams] 

86 

87 

88def _distill_cursor_params(connection, multiparams, params): 

89 """_distill_params without any warnings. more appropriate for 

90 "cursor" params that can include tuple arguments, lists of tuples, 

91 etc. 

92 

93 """ 

94 

95 if not multiparams: 

96 if params: 

97 return [params] 

98 else: 

99 return [] 

100 elif len(multiparams) == 1: 

101 zero = multiparams[0] 

102 if isinstance(zero, (list, tuple)): 

103 if ( 

104 not zero 

105 or hasattr(zero[0], "__iter__") 

106 and not hasattr(zero[0], "strip") 

107 ): 

108 # execute(stmt, [{}, {}, {}, ...]) 

109 # execute(stmt, [(), (), (), ...]) 

110 return zero 

111 else: 

112 # this is used by exec_driver_sql only, so a deprecation 

113 # warning would already be coming from passing a plain 

114 # textual statement with positional parameters to 

115 # execute(). 

116 # execute(stmt, ("value", "value")) 

117 

118 return [zero] 

119 elif hasattr(zero, "keys"): 

120 # execute(stmt, {"key":"value"}) 

121 return [zero] 

122 else: 

123 # execute(stmt, "value") 

124 return [[zero]] 

125 else: 

126 if hasattr(multiparams[0], "__iter__") and not hasattr( 

127 multiparams[0], "strip" 

128 ): 

129 return multiparams 

130 else: 

131 return [multiparams] 

132 

133 

134def _distill_params_20(params): 

135 if params is None: 

136 return _no_tuple, _no_kw 

137 elif isinstance(params, list): 

138 # collections_abc.MutableSequence): # avoid abc.__instancecheck__ 

139 if params and not isinstance( 

140 params[0], (collections_abc.Mapping, tuple) 

141 ): 

142 raise exc.ArgumentError( 

143 "List argument must consist only of tuples or dictionaries" 

144 ) 

145 

146 return (params,), _no_kw 

147 elif isinstance( 

148 params, 

149 (tuple, dict, immutabledict), 

150 # only do abc.__instancecheck__ for Mapping after we've checked 

151 # for plain dictionaries and would otherwise raise 

152 ) or isinstance(params, collections_abc.Mapping): 

153 return (params,), _no_kw 

154 else: 

155 raise exc.ArgumentError("mapping or sequence expected for parameters") 

156 

157 

158class TransactionalContext(object): 

159 """Apply Python context manager behavior to transaction objects. 

160 

161 Performs validation to ensure the subject of the transaction is not 

162 used if the transaction were ended prematurely. 

163 

164 """ 

165 

166 _trans_subject = None 

167 

168 def _transaction_is_active(self): 

169 raise NotImplementedError() 

170 

171 def _transaction_is_closed(self): 

172 raise NotImplementedError() 

173 

174 def _rollback_can_be_called(self): 

175 """indicates the object is in a state that is known to be acceptable 

176 for rollback() to be called. 

177 

178 This does not necessarily mean rollback() will succeed or not raise 

179 an error, just that there is currently no state detected that indicates 

180 rollback() would fail or emit warnings. 

181 

182 It also does not mean that there's a transaction in progress, as 

183 it is usually safe to call rollback() even if no transaction is 

184 present. 

185 

186 .. versionadded:: 1.4.28 

187 

188 """ 

189 raise NotImplementedError() 

190 

191 def _get_subject(self): 

192 raise NotImplementedError() 

193 

194 @classmethod 

195 def _trans_ctx_check(cls, subject): 

196 trans_context = subject._trans_context_manager 

197 if trans_context: 

198 if not trans_context._transaction_is_active(): 

199 raise exc.InvalidRequestError( 

200 "Can't operate on closed transaction inside context " 

201 "manager. Please complete the context manager " 

202 "before emitting further commands." 

203 ) 

204 

205 def __enter__(self): 

206 subject = self._get_subject() 

207 

208 # none for outer transaction, may be non-None for nested 

209 # savepoint, legacy nesting cases 

210 trans_context = subject._trans_context_manager 

211 self._outer_trans_ctx = trans_context 

212 

213 self._trans_subject = subject 

214 subject._trans_context_manager = self 

215 return self 

216 

217 def __exit__(self, type_, value, traceback): 

218 subject = self._trans_subject 

219 

220 # simplistically we could assume that 

221 # "subject._trans_context_manager is self". However, any calling 

222 # code that is manipulating __exit__ directly would break this 

223 # assumption. alembic context manager 

224 # is an example of partial use that just calls __exit__ and 

225 # not __enter__ at the moment. it's safe to assume this is being done 

226 # in the wild also 

227 out_of_band_exit = ( 

228 subject is None or subject._trans_context_manager is not self 

229 ) 

230 

231 if type_ is None and self._transaction_is_active(): 

232 try: 

233 self.commit() 

234 except: 

235 with util.safe_reraise(): 

236 if self._rollback_can_be_called(): 

237 self.rollback() 

238 finally: 

239 if not out_of_band_exit: 

240 subject._trans_context_manager = self._outer_trans_ctx 

241 self._trans_subject = self._outer_trans_ctx = None 

242 else: 

243 try: 

244 if not self._transaction_is_active(): 

245 if not self._transaction_is_closed(): 

246 self.close() 

247 else: 

248 if self._rollback_can_be_called(): 

249 self.rollback() 

250 finally: 

251 if not out_of_band_exit: 

252 subject._trans_context_manager = self._outer_trans_ctx 

253 self._trans_subject = self._outer_trans_ctx = None