1 | """
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2 | util.py
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3 | """
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4 | from __future__ import print_function
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5 |
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6 | import sys
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7 | from mypy.nodes import (CallExpr, IfStmt, Block, Expression, MypyFile,
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8 | MemberExpr, IntExpr, NameExpr, ComparisonExpr)
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9 | from mypy.types import Instance, Type
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10 |
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11 | from typing import Any, Sequence, Optional
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12 |
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13 | # Used by cppgen_pass and const_pass
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14 |
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15 | # mycpp/examples/small_str.py sorta works with this!
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16 | #SMALL_STR = True
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17 |
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18 | SMALL_STR = False
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19 |
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20 | SymbolPath = Sequence[str]
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21 |
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22 |
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23 | def log(msg: str, *args: Any) -> None:
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24 | if args:
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25 | msg = msg % args
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26 | print(msg, file=sys.stderr)
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27 |
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28 |
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29 | def join_name(parts: SymbolPath,
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30 | strip_package: bool = False,
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31 | delim: str = '::') -> str:
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32 | """
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33 | Join the given name path into a string with the given delimiter.
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34 | Use strip_package to remove the top-level directory (e.g. `core`, `ysh`)
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35 | when dealing with C++ namespaces.
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36 | """
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37 | if not strip_package:
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38 | return delim.join(parts)
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39 |
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40 | if len(parts) > 1:
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41 | return delim.join(('', ) + parts[1:])
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42 |
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43 | return parts[0]
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44 |
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45 |
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46 | def split_py_name(name: str) -> SymbolPath:
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47 | ret = tuple(name.split('.'))
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48 | if len(ret) and ret[0] == 'mycpp':
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49 | # Drop the prefix 'mycpp.' if present. This makes names compatible with
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50 | # the examples that use testpkg.
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51 | return ret[1:]
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52 |
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53 | return ret
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54 |
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55 |
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56 | def _collect_cases(module_path: str,
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57 | if_node: IfStmt,
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58 | out: list[tuple[Expression, Block]],
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59 | errors=None) -> Optional[Block] | bool:
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60 | """
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61 | The MyPy AST has a recursive structure for if-elif-elif rather than a
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62 | flat one. It's a bit confusing.
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63 |
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64 | Appends (expr, block) cases to out param, and returns the default
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65 | block, which has no expression.
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66 |
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67 | default block may be None.
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68 |
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69 | Returns False if there is no default block.
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70 | """
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71 | assert isinstance(if_node, IfStmt), if_node
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72 | assert len(if_node.expr) == 1, if_node.expr
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73 | assert len(if_node.body) == 1, if_node.body
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74 |
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75 | expr = if_node.expr[0]
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76 | body = if_node.body[0]
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77 |
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78 | if not isinstance(expr, CallExpr):
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79 | if errors is not None:
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80 | errors.append((module_path, expr.line,
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81 | 'Expected call like case(x), got %s' % expr))
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82 | return
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83 |
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84 | out.append((expr, body))
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85 |
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86 | if if_node.else_body:
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87 | first_of_block = if_node.else_body.body[0]
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88 | # BUG: this is meant for 'elif' only. But it also triggers for
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89 | #
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90 | # else:
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91 | # if 0:
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92 |
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93 | if isinstance(first_of_block, IfStmt):
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94 | return _collect_cases(module_path, first_of_block, out, errors)
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95 | else:
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96 | # default case - no expression
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97 | return if_node.else_body
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98 |
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99 | return False # NO DEFAULT BLOCK - Different than None
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100 |
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101 |
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102 | def ShouldSkipPyFile(node: MypyFile) -> bool:
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103 | # Skip some stdlib stuff. A lot of it is brought in by 'import
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104 | # typing'. These module are special; their contents are currently all
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105 | # built-in primitives.
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106 | return node.fullname in ('__future__', 'sys', 'types', 'typing', 'abc',
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107 | '_ast', 'ast', '_weakrefset', 'collections',
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108 | 'cStringIO', 're', 'builtins')
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109 |
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110 |
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111 | def IsStr(t: Type):
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112 | """Helper to check if a type is a string."""
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113 | return isinstance(t, Instance) and t.type.fullname == 'builtins.str'
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114 |
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115 |
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116 | def _ShouldSkipIf(stmt: IfStmt) -> bool:
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117 | cond = stmt.expr[0]
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118 |
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119 | # Omit anything that looks like if __name__ == ...
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120 | if (isinstance(cond, ComparisonExpr) and
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121 | isinstance(cond.operands[0], NameExpr) and
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122 | cond.operands[0].name == '__name__'):
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123 | return True
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124 |
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125 | if isinstance(cond, NameExpr) and cond.name == 'TYPE_CHECKING':
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126 | # Omit if TYPE_CHECKING blocks. They contain type expressions that
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127 | # don't type check!
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128 | return True
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129 |
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130 | return False
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131 |
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132 |
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133 | def GetSpecialIfCondition(stmt: IfStmt) -> Optional[str]:
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134 | cond = stmt.expr[0]
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135 | if isinstance(cond, NameExpr) and cond.name == 'TYPE_CHECKING':
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136 | return cond.name
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137 |
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138 | if isinstance(cond, MemberExpr) and cond.name in ('PYTHON', 'CPP'):
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139 | return cond.name
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140 |
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141 | return None
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142 |
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143 |
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144 | def ShouldVisitIfExpr(stmt: IfStmt) -> bool:
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145 | if _ShouldSkipIf(stmt) or GetSpecialIfCondition(stmt) in ('PYTHON', 'CPP'):
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146 | return False
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147 |
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148 | cond = stmt.expr[0]
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149 | if isinstance(cond, IntExpr) and cond.value == 0:
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150 | return False
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151 |
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152 | return True
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153 |
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154 |
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155 | def ShouldVisitIfBody(stmt: IfStmt) -> bool:
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156 | if _ShouldSkipIf(stmt):
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157 | return False
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158 |
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159 | cond = stmt.expr[0]
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160 | if isinstance(cond, MemberExpr) and cond.name == 'PYTHON':
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161 | return False
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162 |
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163 | if isinstance(cond, IntExpr) and cond.value == 0:
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164 | return False
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165 |
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166 | return True
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167 |
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168 |
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169 | def ShouldVisitElseBody(stmt: IfStmt) -> bool:
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170 | if _ShouldSkipIf(stmt):
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171 | return False
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172 |
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173 | cond = stmt.expr[0]
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174 | if isinstance(cond, MemberExpr) and cond.name == 'CPP':
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175 | return False
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176 |
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177 | return stmt.else_body is not None
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