| 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
|