versionpredicate.py 5.0 KB

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  1. """Module for parsing and testing package version predicate strings.
  2. """
  3. import re
  4. import distutils.version
  5. import operator
  6. re_validPackage = re.compile(r"(?i)^\s*([a-z_]\w*(?:\.[a-z_]\w*)*)(.*)",
  7. re.ASCII)
  8. # (package) (rest)
  9. re_paren = re.compile(r"^\s*\((.*)\)\s*$") # (list) inside of parentheses
  10. re_splitComparison = re.compile(r"^\s*(<=|>=|<|>|!=|==)\s*([^\s,]+)\s*$")
  11. # (comp) (version)
  12. def splitUp(pred):
  13. """Parse a single version comparison.
  14. Return (comparison string, StrictVersion)
  15. """
  16. res = re_splitComparison.match(pred)
  17. if not res:
  18. raise ValueError("bad package restriction syntax: %r" % pred)
  19. comp, verStr = res.groups()
  20. return (comp, distutils.version.StrictVersion(verStr))
  21. compmap = {"<": operator.lt, "<=": operator.le, "==": operator.eq,
  22. ">": operator.gt, ">=": operator.ge, "!=": operator.ne}
  23. class VersionPredicate:
  24. """Parse and test package version predicates.
  25. >>> v = VersionPredicate('pyepat.abc (>1.0, <3333.3a1, !=1555.1b3)')
  26. The `name` attribute provides the full dotted name that is given::
  27. >>> v.name
  28. 'pyepat.abc'
  29. The str() of a `VersionPredicate` provides a normalized
  30. human-readable version of the expression::
  31. >>> print(v)
  32. pyepat.abc (> 1.0, < 3333.3a1, != 1555.1b3)
  33. The `satisfied_by()` method can be used to determine with a given
  34. version number is included in the set described by the version
  35. restrictions::
  36. >>> v.satisfied_by('1.1')
  37. True
  38. >>> v.satisfied_by('1.4')
  39. True
  40. >>> v.satisfied_by('1.0')
  41. False
  42. >>> v.satisfied_by('4444.4')
  43. False
  44. >>> v.satisfied_by('1555.1b3')
  45. False
  46. `VersionPredicate` is flexible in accepting extra whitespace::
  47. >>> v = VersionPredicate(' pat( == 0.1 ) ')
  48. >>> v.name
  49. 'pat'
  50. >>> v.satisfied_by('0.1')
  51. True
  52. >>> v.satisfied_by('0.2')
  53. False
  54. If any version numbers passed in do not conform to the
  55. restrictions of `StrictVersion`, a `ValueError` is raised::
  56. >>> v = VersionPredicate('p1.p2.p3.p4(>=1.0, <=1.3a1, !=1.2zb3)')
  57. Traceback (most recent call last):
  58. ...
  59. ValueError: invalid version number '1.2zb3'
  60. It the module or package name given does not conform to what's
  61. allowed as a legal module or package name, `ValueError` is
  62. raised::
  63. >>> v = VersionPredicate('foo-bar')
  64. Traceback (most recent call last):
  65. ...
  66. ValueError: expected parenthesized list: '-bar'
  67. >>> v = VersionPredicate('foo bar (12.21)')
  68. Traceback (most recent call last):
  69. ...
  70. ValueError: expected parenthesized list: 'bar (12.21)'
  71. """
  72. def __init__(self, versionPredicateStr):
  73. """Parse a version predicate string.
  74. """
  75. # Fields:
  76. # name: package name
  77. # pred: list of (comparison string, StrictVersion)
  78. versionPredicateStr = versionPredicateStr.strip()
  79. if not versionPredicateStr:
  80. raise ValueError("empty package restriction")
  81. match = re_validPackage.match(versionPredicateStr)
  82. if not match:
  83. raise ValueError("bad package name in %r" % versionPredicateStr)
  84. self.name, paren = match.groups()
  85. paren = paren.strip()
  86. if paren:
  87. match = re_paren.match(paren)
  88. if not match:
  89. raise ValueError("expected parenthesized list: %r" % paren)
  90. str = match.groups()[0]
  91. self.pred = [splitUp(aPred) for aPred in str.split(",")]
  92. if not self.pred:
  93. raise ValueError("empty parenthesized list in %r"
  94. % versionPredicateStr)
  95. else:
  96. self.pred = []
  97. def __str__(self):
  98. if self.pred:
  99. seq = [cond + " " + str(ver) for cond, ver in self.pred]
  100. return self.name + " (" + ", ".join(seq) + ")"
  101. else:
  102. return self.name
  103. def satisfied_by(self, version):
  104. """True if version is compatible with all the predicates in self.
  105. The parameter version must be acceptable to the StrictVersion
  106. constructor. It may be either a string or StrictVersion.
  107. """
  108. for cond, ver in self.pred:
  109. if not compmap[cond](version, ver):
  110. return False
  111. return True
  112. _provision_rx = None
  113. def split_provision(value):
  114. """Return the name and optional version number of a provision.
  115. The version number, if given, will be returned as a `StrictVersion`
  116. instance, otherwise it will be `None`.
  117. >>> split_provision('mypkg')
  118. ('mypkg', None)
  119. >>> split_provision(' mypkg( 1.2 ) ')
  120. ('mypkg', StrictVersion ('1.2'))
  121. """
  122. global _provision_rx
  123. if _provision_rx is None:
  124. _provision_rx = re.compile(
  125. r"([a-zA-Z_]\w*(?:\.[a-zA-Z_]\w*)*)(?:\s*\(\s*([^)\s]+)\s*\))?$",
  126. re.ASCII)
  127. value = value.strip()
  128. m = _provision_rx.match(value)
  129. if not m:
  130. raise ValueError("illegal provides specification: %r" % value)
  131. ver = m.group(2) or None
  132. if ver:
  133. ver = distutils.version.StrictVersion(ver)
  134. return m.group(1), ver