Mercurial Repositories > Radon Code Metrics / file comparison
comparison: RadonMetrics/radon/complexity.py
RadonMetrics/radon/complexity.py
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| 1 '''This module contains all high-level helpers function that allow to work with | |
| 2 Cyclomatic Complexity | |
| 3 ''' | |
| 4 | |
| 5 import math | |
| 6 from radon.visitors import GET_COMPLEXITY, ComplexityVisitor, code2ast | |
| 7 | |
| 8 | |
| 9 # sorted_block ordering functions | |
| 10 SCORE = lambda block: -GET_COMPLEXITY(block) | |
| 11 LINES = lambda block: block.lineno | |
| 12 ALPHA = lambda block: block.name | |
| 13 | |
| 14 | |
| 15 def cc_rank(cc): | |
| 16 r'''Rank the complexity score from A to F, where A stands for the simplest | |
| 17 and best score and F the most complex and worst one: | |
| 18 | |
| 19 ============= ===================================================== | |
| 20 1 - 5 A (low risk - simple block) | |
| 21 6 - 10 B (low risk - well structured and stable block) | |
| 22 11 - 20 C (moderate risk - slightly complex block) | |
| 23 21 - 30 D (more than moderate risk - more complex block) | |
| 24 31 - 40 E (high risk - complex block, alarming) | |
| 25 41+ F (very high risk - error-prone, unstable block) | |
| 26 ============= ===================================================== | |
| 27 | |
| 28 Here *block* is used in place of function, method or class. | |
| 29 | |
| 30 The formula used to convert the score into an index is the following: | |
| 31 | |
| 32 .. math:: | |
| 33 | |
| 34 \text{rank} = \left \lceil \dfrac{\text{score}}{10} \right \rceil | |
| 35 - H(5 - \text{score}) | |
| 36 | |
| 37 where ``H(s)`` stands for the Heaviside Step Function. | |
| 38 The rank is then associated to a letter (0 = A, 5 = F). | |
| 39 ''' | |
| 40 if cc < 0: | |
| 41 raise ValueError('Complexity must be a non-negative value') | |
| 42 return chr(min(int(math.ceil(cc / 10.) or 1) - (1, 0)[5 - cc < 0], 5) + 65) | |
| 43 | |
| 44 | |
| 45 def average_complexity(blocks): | |
| 46 '''Compute the average Cyclomatic complexity from the given blocks. | |
| 47 Blocks must be either :class:`~radon.visitors.Function` or | |
| 48 :class:`~radon.visitors.Class`. If the block list is empty, then 0 is | |
| 49 returned. | |
| 50 ''' | |
| 51 size = len(blocks) | |
| 52 if size == 0: | |
| 53 return 0 | |
| 54 return sum((GET_COMPLEXITY(block) for block in blocks), .0) / len(blocks) | |
| 55 | |
| 56 | |
| 57 def sorted_results(blocks, order=SCORE): | |
| 58 '''Given a ComplexityVisitor instance, returns a list of sorted blocks | |
| 59 with respect to complexity. A block is a either | |
| 60 :class:`~radon.visitors.Function` object or a | |
| 61 :class:`~radon.visitors.Class` object. | |
| 62 The blocks are sorted in descending order from the block with the highest | |
| 63 complexity. | |
| 64 | |
| 65 The optional `order` parameter indicates how to sort the blocks. It can be: | |
| 66 | |
| 67 * `LINES`: sort by line numbering; | |
| 68 * `ALPHA`: sort by name (from A to Z); | |
| 69 * `SCORE`: sorty by score (descending). | |
| 70 | |
| 71 Default is `SCORE`. | |
| 72 ''' | |
| 73 return sorted(blocks, key=order) | |
| 74 | |
| 75 | |
| 76 def add_closures(blocks): | |
| 77 '''Process a list of blocks by adding all closures as top-level blocks.''' | |
| 78 new_blocks = [] | |
| 79 for block in blocks: | |
| 80 new_blocks.append(block) | |
| 81 if 'closures' not in block._fields: | |
| 82 continue | |
| 83 for closure in block.closures: | |
| 84 named = closure._replace(name=block.name + '.' + closure.name) | |
| 85 new_blocks.append(named) | |
| 86 return new_blocks | |
| 87 | |
| 88 | |
| 89 def cc_visit(code, **kwargs): | |
| 90 '''Visit the given code with :class:`~radon.visitors.ComplexityVisitor`. | |
| 91 All the keyword arguments are directly passed to the visitor. | |
| 92 ''' | |
| 93 return cc_visit_ast(code2ast(code), **kwargs) | |
| 94 | |
| 95 | |
| 96 def cc_visit_ast(ast_node, **kwargs): | |
| 97 '''Visit the AST node with :class:`~radon.visitors.ComplexityVisitor`. All | |
| 98 the keyword arguments are directly passed to the visitor. | |
| 99 ''' | |
| 100 return ComplexityVisitor.from_ast(ast_node, **kwargs).blocks | |
| 101 | |
| 102 | |
| 103 class Flake8Checker(object): | |
| 104 '''Entry point for the Flake8 tool.''' | |
| 105 | |
| 106 name = 'radon' | |
| 107 _code = 'R701' | |
| 108 _error_tmpl = 'R701: %r is too complex (%d)' | |
| 109 no_assert = False | |
| 110 max_cc = -1 | |
| 111 | |
| 112 def __init__(self, tree, filename): | |
| 113 '''Accept the AST tree and a filename (unused).''' | |
| 114 self.tree = tree | |
| 115 | |
| 116 version = property(lambda self: __import__('radon').__version__) | |
| 117 | |
| 118 @classmethod | |
| 119 def add_options(cls, parser): # pragma: no cover | |
| 120 '''Add custom options to the global parser.''' | |
| 121 parser.add_option('--radon-max-cc', default=-1, action='store', | |
| 122 type='int', help='Radon complexity threshold') | |
| 123 parser.add_option('--radon-no-assert', dest='no_assert', | |
| 124 action='store_true', default=False, | |
| 125 help='Radon will ignore assert statements') | |
| 126 parser.config_options.append('radon-max-cc') | |
| 127 parser.config_options.append('radon-no-assert') | |
| 128 | |
| 129 @classmethod | |
| 130 def parse_options(cls, options): # pragma: no cover | |
| 131 '''Save actual options as class attributes.''' | |
| 132 cls.max_cc = options.radon_max_cc | |
| 133 cls.no_assert = options.no_assert | |
| 134 | |
| 135 def run(self): | |
| 136 '''Run the ComplexityVisitor over the AST tree.''' | |
| 137 if self.max_cc < 0: | |
| 138 if not self.no_assert: | |
| 139 return | |
| 140 self.max_cc = 10 | |
| 141 visitor = ComplexityVisitor.from_ast(self.tree, | |
| 142 no_assert=self.no_assert) | |
| 143 for block in visitor.blocks: | |
| 144 if block.complexity > self.max_cc: | |
| 145 text = self._error_tmpl % (block.name, block.complexity) | |
| 146 yield block.lineno, 0, text, type(self) |
