Hide keyboard shortcuts

Hot-keys on this page

r m x p   toggle line displays

j k   next/prev highlighted chunk

0   (zero) top of page

1   (one) first highlighted chunk

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

# This file is part of daf_butler. 

# 

# Developed for the LSST Data Management System. 

# This product includes software developed by the LSST Project 

# (http://www.lsst.org). 

# See the COPYRIGHT file at the top-level directory of this distribution 

# for details of code ownership. 

# 

# This program is free software: you can redistribute it and/or modify 

# it under the terms of the GNU General Public License as published by 

# the Free Software Foundation, either version 3 of the License, or 

# (at your option) any later version. 

# 

# This program is distributed in the hope that it will be useful, 

# but WITHOUT ANY WARRANTY; without even the implied warranty of 

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

# GNU General Public License for more details. 

# 

# You should have received a copy of the GNU General Public License 

# along with this program. If not, see <http://www.gnu.org/licenses/>. 

 

"""Support for Storage Classes.""" 

 

import builtins 

import itertools 

import logging 

 

from .utils import doImport, Singleton, getFullTypeName 

from .assembler import CompositeAssembler 

from .config import ConfigSubset 

 

log = logging.getLogger(__name__) 

 

__all__ = ("StorageClass", "StorageClassFactory", "StorageClassConfig") 

 

 

class StorageClassConfig(ConfigSubset): 

component = "storageClasses" 

defaultConfigFile = "storageClasses.yaml" 

 

 

class StorageClass: 

"""Class describing how a label maps to a particular Python type. 

 

Parameters 

---------- 

name : `str` 

Name to use for this class. 

pytype : `type` 

Python type (or name of type) to associate with the `StorageClass` 

components : `dict`, optional 

`dict` mapping name of a component to another `StorageClass`. 

assembler : `str`, optional 

Fully qualified name of class supporting assembly and disassembly 

of a `pytype` instance. 

""" 

defaultAssembler = CompositeAssembler 

defaultAssemblerName = getFullTypeName(defaultAssembler) 

 

def __init__(self, name, pytype=None, components=None, assembler=None): 

self.name = name 

self._pytypeName = pytype 

if pytype is None: 

self._pytypeName = "object" 

self._pytype = object 

self._components = components if components is not None else {} 

# if the assembler is not None also set it and clear the default 

# assembler 

if assembler is not None: 

self._assemblerClassName = assembler 

self._assembler = None 

elif components is not None: 

# We set a default assembler for composites so that a class is 

# guaranteed to support something if it is a composite. 

log.debug("Setting default assembler for %s", self.name) 

self._assembler = self.defaultAssembler 

self._assemblerClassName = self.defaultAssemblerName 

else: 

self._assembler = None 

self._assemblerClassName = None 

# The types are created on demand and cached 

self._pytype = None 

 

@property 

def components(self): 

"""Component names mapped to associated `StorageClass` 

""" 

return self._components 

 

@property 

def pytype(self): 

"""Python type associated with this `StorageClass`.""" 

if self._pytype is not None: 

return self._pytype 

# Handle case where we did get a python type not string 

if not isinstance(self._pytypeName, str): 

pytype = self._pytypeName 

self._pytypeName = self._pytypeName.__name__ 

elif hasattr(builtins, self._pytypeName): 

pytype = getattr(builtins, self._pytypeName) 

else: 

pytype = doImport(self._pytypeName) 

self._pytype = pytype 

return self._pytype 

 

@property 

def assemblerClass(self): 

"""Class to use to (dis)assemble an object from components.""" 

if self._assembler is not None: 

return self._assembler 

111 ↛ 112line 111 didn't jump to line 112, because the condition on line 111 was never true if self._assemblerClassName is None: 

return None 

self._assembler = doImport(self._assemblerClassName) 

return self._assembler 

 

def assembler(self): 

"""Return an instance of an assembler. 

 

Returns 

------- 

assembler : `CompositeAssembler` 

Instance of the assembler associated with this `StorageClass`. 

Assembler is constructed with this `StorageClass`. 

""" 

cls = self.assemblerClass 

return cls(storageClass=self) 

 

def validateInstance(self, instance): 

"""Check that the supplied Python object has the expected Python type 

 

Parameters 

---------- 

instance : `object` 

Object to check. 

 

Returns 

------- 

isOk : `bool` 

True if the supplied instance object can be handled by this 

`StorageClass`, False otherwise. 

""" 

return isinstance(instance, self.pytype) 

 

def __eq__(self, other): 

"""Equality checks name, pytype name, assembler name, and components""" 

if self.name != other.name: 

return False 

 

149 ↛ 150line 149 didn't jump to line 150, because the condition on line 149 was never true if type(self) != type(other): 

return False 

 

# We must compare pytype and assembler by name since we do not want 

# to trigger an import of external module code here 

if self._assemblerClassName != other._assemblerClassName: 

return False 

if self._pytypeName != other._pytypeName: 

return False 

 

# Ensure we have the same component keys in each 

if set(self.components.keys()) != set(other.components.keys()): 

return False 

 

# Ensure that all the components have the same type 

for k in self.components: 

if self.components[k] != other.components[k]: 

return False 

 

# If we got to this point everything checks out 

return True 

 

def __hash__(self): 

return hash(self.name) 

 

def __repr__(self): 

return "{}({}, pytype={}, components={})".format(type(self).__qualname__, 

self.name, 

self.pytype, 

list(self.components.keys())) 

 

 

class StorageClassFactory(metaclass=Singleton): 

"""Factory for `StorageClass` instances. 

 

This class is a singleton, with each instance sharing the pool of 

StorageClasses. Since code can not know whether it is the first 

time the instance has been created, the constructor takes no arguments. 

To populate the factory with storage classes, a call to 

`~StorageClassFactory.addFromConfig()` should be made. 

 

Parameters 

---------- 

config : `StorageClassConfig` or `str`, optional 

Load configuration. In a ButlerConfig` the relevant configuration 

is located in the ``storageClasses`` section. 

""" 

 

def __init__(self, config=None): 

self._storageClasses = {} 

self._configs = [] 

 

201 ↛ 202line 201 didn't jump to line 202, because the condition on line 201 was never true if config is not None: 

self.addFromConfig(config) 

 

def __contains__(self, storageClassOrName): 

"""Indicates whether the storage class exists in the factory. 

 

Parameters 

---------- 

storageClassOrName : `str` or `StorageClass` 

If `str` is given existence of the named StorageClass 

in the factory is checked. If `StorageClass` is given 

existence and equality are checked. 

 

Returns 

------- 

in : `bool` 

True if the supplied string is present, or if the supplied 

`StorageClass` is present and identical. 

 

Notes 

----- 

The two different checks (one for "key" and one for "value") based on 

the type of the given argument mean that it is possible for 

StorageClass.name to be in the factory but StorageClass to not be 

in the factory. 

""" 

if isinstance(storageClassOrName, str): 

return storageClassOrName in self._storageClasses 

elif isinstance(storageClassOrName, StorageClass): 

if storageClassOrName.name in self._storageClasses: 

return storageClassOrName == self._storageClasses[storageClassOrName.name] 

return False 

 

def addFromConfig(self, config): 

"""Add more `StorageClass` definitions from a config file. 

 

Parameters 

---------- 

config : `StorageClassConfig`, `Config` or `str` 

Storage class configuration. Can contain a ``storageClasses`` 

key if part of a global configuration. 

""" 

sconfig = StorageClassConfig(config) 

self._configs.append(sconfig) 

 

# Since we can not assume that we will get definitions of 

# components before the definitions of the composites, we create 

# two lists 

composites = {} 

simple = {} 

for name, info in sconfig.items(): 

if "components" in info: 

composites[name] = info 

else: 

simple[name] = info 

 

for name in itertools.chain(simple, composites): 

info = sconfig[name] 

 

# Always create the storage class so we can ensure that 

# we are not trying to overwrite with a different definition 

components = None 

if "components" in info: 

components = {} 

for cname, ctype in info["components"].items(): 

components[cname] = self.getStorageClass(ctype) 

 

# Extract scalar items from dict that are needed for StorageClass Constructor 

storageClassKwargs = {k: info[k] for k in ("pytype", "assembler") if k in info} 

 

# Fill in other items 

storageClassKwargs["components"] = components 

 

# Create the new storage class and register it 

newStorageClass = StorageClass(name, **storageClassKwargs) 

self.registerStorageClass(newStorageClass) 

 

def getStorageClass(self, storageClassName): 

"""Get a StorageClass instance associated with the supplied name. 

 

Parameters 

---------- 

storageClassName : `str` 

Name of the storage class to retrieve. 

 

Returns 

------- 

instance : `StorageClass` 

Instance of the correct `StorageClass`. 

""" 

return self._storageClasses[storageClassName] 

 

def registerStorageClass(self, storageClass): 

"""Store the `StorageClass` in the factory. 

 

Will be indexed by `StorageClass.name` and will return instances 

of the supplied `StorageClass`. 

 

Parameters 

---------- 

storageClass : `StorageClass` 

Type of the Python `StorageClass` to register. 

 

Raises 

------ 

ValueError 

If a storage class has already been registered with 

storageClassName and the previous definition differs. 

""" 

if storageClass.name in self._storageClasses: 

existing = self.getStorageClass(storageClass.name) 

if existing != storageClass: 

raise ValueError(f"New definition for StorageClass {storageClass.name} differs from current" 

" definition") 

else: 

self._storageClasses[storageClass.name] = storageClass 

 

def _unregisterStorageClass(self, storageClassName): 

"""Remove the named StorageClass from the factory. 

 

Parameters 

---------- 

storageClassName : `str` 

Name of storage class to remove. 

 

Raises 

------ 

KeyError 

The named storage class is not registered. 

 

Notes 

----- 

This method is intended to simplify testing of StorageClassFactory 

functionality and it is not expected to be required for normal usage. 

""" 

del self._storageClasses[storageClassName]