| 1 | """vm.py: Library for executing shell."""
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| 2 | from __future__ import print_function
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| 3 |
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| 4 | from _devbuild.gen.id_kind_asdl import Id
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| 5 | from _devbuild.gen.runtime_asdl import (CommandStatus, StatusArray, flow_e,
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| 6 | flow_t)
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| 7 | from _devbuild.gen.syntax_asdl import Token
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| 8 | from _devbuild.gen.value_asdl import value_t, Obj
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| 9 | from core import error
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| 10 | from core import pyos
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| 11 | from mycpp.mylib import log
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| 12 |
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| 13 | from typing import List, Tuple, Any, TYPE_CHECKING
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| 14 | if TYPE_CHECKING:
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| 15 | from _devbuild.gen.runtime_asdl import cmd_value, RedirValue
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| 16 | from _devbuild.gen.syntax_asdl import (command, command_t, CommandSub)
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| 17 | from frontend import typed_args
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| 18 | from osh import sh_expr_eval
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| 19 | from osh.sh_expr_eval import ArithEvaluator
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| 20 | from osh.sh_expr_eval import BoolEvaluator
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| 21 | from ysh.expr_eval import ExprEvaluator
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| 22 | from osh.word_eval import NormalWordEvaluator
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| 23 | from osh.cmd_eval import CommandEvaluator
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| 24 | from osh import prompt
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| 25 | from core import dev
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| 26 | from core import state
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| 27 |
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| 28 | _ = log
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| 29 |
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| 30 |
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| 31 | class ControlFlow(Exception):
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| 32 | """Internal exception for control flow.
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| 33 |
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| 34 | Used by CommandEvaluator and 'source' builtin
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| 35 |
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| 36 | break and continue are caught by loops, return is caught by functions.
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| 37 | """
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| 38 | pass
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| 39 |
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| 40 |
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| 41 | class IntControlFlow(Exception):
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| 42 |
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| 43 | def __init__(self, token, arg):
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| 44 | # type: (Token, int) -> None
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| 45 | """
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| 46 | Args:
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| 47 | token: the keyword token
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| 48 | arg: exit code to 'return', or number of levels to break/continue
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| 49 | """
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| 50 | self.token = token
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| 51 | self.arg = arg
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| 52 |
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| 53 | def IsReturn(self):
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| 54 | # type: () -> bool
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| 55 | return self.token.id == Id.ControlFlow_Return
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| 56 |
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| 57 | def IsBreak(self):
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| 58 | # type: () -> bool
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| 59 | return self.token.id == Id.ControlFlow_Break
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| 60 |
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| 61 | def IsContinue(self):
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| 62 | # type: () -> bool
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| 63 | return self.token.id == Id.ControlFlow_Continue
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| 64 |
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| 65 | def StatusCode(self):
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| 66 | # type: () -> int
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| 67 | assert self.IsReturn()
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| 68 | # All shells except dash do this truncation.
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| 69 | # turn 257 into 1, and -1 into 255.
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| 70 | return self.arg & 0xff
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| 71 |
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| 72 | def HandleLoop(self):
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| 73 | # type: () -> flow_t
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| 74 | """Mutates this exception and returns what the caller should do."""
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| 75 |
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| 76 | if self.IsBreak():
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| 77 | self.arg -= 1
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| 78 | if self.arg == 0:
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| 79 | return flow_e.Break # caller should break out of loop
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| 80 |
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| 81 | elif self.IsContinue():
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| 82 | self.arg -= 1
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| 83 | if self.arg == 0:
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| 84 | return flow_e.Nothing # do nothing to continue
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| 85 |
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| 86 | # return / break 2 / continue 2 need to pop up more
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| 87 | return flow_e.Raise
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| 88 |
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| 89 | def __repr__(self):
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| 90 | # type: () -> str
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| 91 | return '<IntControlFlow %s %s>' % (self.token, self.arg)
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| 92 |
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| 93 |
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| 94 | class ValueControlFlow(Exception):
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| 95 |
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| 96 | def __init__(self, token, value):
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| 97 | # type: (Token, value_t) -> None
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| 98 | """
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| 99 | Args:
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| 100 | token: the keyword token
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| 101 | value: value_t to 'return' from a function
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| 102 | """
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| 103 | self.token = token
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| 104 | self.value = value
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| 105 |
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| 106 | def __repr__(self):
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| 107 | # type: () -> str
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| 108 | return '<ValueControlFlow %s %s>' % (self.token, self.value)
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| 109 |
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| 110 |
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| 111 | def InitUnsafeArith(mem, word_ev, unsafe_arith):
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| 112 | # type: (state.Mem, NormalWordEvaluator, sh_expr_eval.UnsafeArith) -> None
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| 113 | """Wire up circular dependencies for UnsafeArith."""
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| 114 | mem.unsafe_arith = unsafe_arith # for 'declare -n' nameref expansion of a[i]
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| 115 | word_ev.unsafe_arith = unsafe_arith # for ${!ref} expansion of a[i]
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| 116 |
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| 117 |
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| 118 | def InitCircularDeps(
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| 119 | arith_ev, # type: ArithEvaluator
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| 120 | bool_ev, # type: BoolEvaluator
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| 121 | expr_ev, # type: ExprEvaluator
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| 122 | word_ev, # type: NormalWordEvaluator
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| 123 | cmd_ev, # type: CommandEvaluator
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| 124 | shell_ex, # type: _Executor
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| 125 | prompt_ev, # type: prompt.Evaluator
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| 126 | global_io, # type: Obj
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| 127 | tracer, # type: dev.Tracer
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| 128 | ):
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| 129 | # type: (...) -> None
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| 130 | """Wire up mutually recursive evaluators and runtime objects."""
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| 131 | arith_ev.word_ev = word_ev
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| 132 | bool_ev.word_ev = word_ev
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| 133 |
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| 134 | if expr_ev: # for pure OSH
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| 135 | expr_ev.shell_ex = shell_ex
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| 136 | expr_ev.cmd_ev = cmd_ev
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| 137 | expr_ev.word_ev = word_ev
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| 138 |
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| 139 | word_ev.arith_ev = arith_ev
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| 140 | word_ev.expr_ev = expr_ev
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| 141 | word_ev.prompt_ev = prompt_ev
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| 142 | word_ev.shell_ex = shell_ex
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| 143 |
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| 144 | cmd_ev.shell_ex = shell_ex
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| 145 | cmd_ev.arith_ev = arith_ev
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| 146 | cmd_ev.bool_ev = bool_ev
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| 147 | cmd_ev.expr_ev = expr_ev
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| 148 | cmd_ev.word_ev = word_ev
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| 149 | cmd_ev.tracer = tracer
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| 150 |
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| 151 | shell_ex.cmd_ev = cmd_ev
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| 152 |
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| 153 | prompt_ev.word_ev = word_ev
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| 154 | prompt_ev.expr_ev = expr_ev
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| 155 | prompt_ev.global_io = global_io
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| 156 |
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| 157 | tracer.word_ev = word_ev
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| 158 |
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| 159 | arith_ev.CheckCircularDeps()
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| 160 | bool_ev.CheckCircularDeps()
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| 161 | if expr_ev:
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| 162 | expr_ev.CheckCircularDeps()
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| 163 | word_ev.CheckCircularDeps()
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| 164 | cmd_ev.CheckCircularDeps()
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| 165 | shell_ex.CheckCircularDeps()
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| 166 | prompt_ev.CheckCircularDeps()
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| 167 | tracer.CheckCircularDeps()
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| 168 |
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| 169 |
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| 170 | class _Executor(object):
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| 171 |
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| 172 | def __init__(self):
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| 173 | # type: () -> None
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| 174 | self.cmd_ev = None # type: CommandEvaluator
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| 175 |
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| 176 | def CheckCircularDeps(self):
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| 177 | # type: () -> None
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| 178 | pass
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| 179 |
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| 180 | def RunBuiltin(self, builtin_id, cmd_val):
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| 181 | # type: (int, cmd_value.Argv) -> int
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| 182 | """The 'builtin' builtin in osh/builtin_meta.py needs this."""
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| 183 | return 0
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| 184 |
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| 185 | def RunSimpleCommand(self, cmd_val, cmd_st, run_flags):
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| 186 | # type: (cmd_value.Argv, CommandStatus, int) -> int
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| 187 | return 0
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| 188 |
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| 189 | def RunBackgroundJob(self, node):
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| 190 | # type: (command_t) -> int
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| 191 | return 0
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| 192 |
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| 193 | def RunPipeline(self, node, status_out):
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| 194 | # type: (command.Pipeline, CommandStatus) -> None
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| 195 | pass
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| 196 |
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| 197 | def RunSubshell(self, node):
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| 198 | # type: (command_t) -> int
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| 199 | return 0
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| 200 |
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| 201 | def CaptureStdout(self, node):
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| 202 | # type: (command_t) -> Tuple[int, str]
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| 203 | return 0, ''
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| 204 |
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| 205 | def RunCommandSub(self, cs_part):
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| 206 | # type: (CommandSub) -> str
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| 207 | return ''
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| 208 |
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| 209 | def RunProcessSub(self, cs_part):
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| 210 | # type: (CommandSub) -> str
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| 211 | return ''
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| 212 |
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| 213 | def PushRedirects(self, redirects, err_out):
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| 214 | # type: (List[RedirValue], List[error.IOError_OSError]) -> None
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| 215 | pass
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| 216 |
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| 217 | def PopRedirects(self, num_redirects, err_out):
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| 218 | # type: (int, List[error.IOError_OSError]) -> None
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| 219 | pass
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| 220 |
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| 221 | def PushProcessSub(self):
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| 222 | # type: () -> None
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| 223 | pass
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| 224 |
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| 225 | def PopProcessSub(self, compound_st):
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| 226 | # type: (StatusArray) -> None
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| 227 | pass
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| 228 |
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| 229 |
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| 230 | #
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| 231 | # Abstract base classes
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| 232 | #
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| 233 |
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| 234 |
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| 235 | class _AssignBuiltin(object):
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| 236 | """Interface for assignment builtins."""
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| 237 |
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| 238 | def __init__(self):
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| 239 | # type: () -> None
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| 240 | """Empty constructor for mycpp."""
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| 241 | pass
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| 242 |
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| 243 | def Run(self, cmd_val):
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| 244 | # type: (cmd_value.Assign) -> int
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| 245 | raise NotImplementedError()
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| 246 |
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| 247 |
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| 248 | class _Builtin(object):
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| 249 | """All builtins except 'command' obey this interface.
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| 250 |
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| 251 | Assignment builtins use cmd_value.Assign; others use cmd_value.Argv.
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| 252 | """
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| 253 |
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| 254 | def __init__(self):
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| 255 | # type: () -> None
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| 256 | """Empty constructor for mycpp."""
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| 257 | pass
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| 258 |
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| 259 | def Run(self, cmd_val):
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| 260 | # type: (cmd_value.Argv) -> int
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| 261 | raise NotImplementedError()
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| 262 |
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| 263 |
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| 264 | class _Callable(object):
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| 265 | """Interface for functions in the runtime."""
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| 266 |
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| 267 | def __init__(self):
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| 268 | # type: () -> None
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| 269 | """Empty constructor for mycpp."""
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| 270 | pass
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| 271 |
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| 272 | def Call(self, args):
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| 273 | # type: (typed_args.Reader) -> value_t
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| 274 | raise NotImplementedError()
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| 275 |
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| 276 |
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| 277 | class ctx_Redirect(object):
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| 278 | """For closing files.
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| 279 |
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| 280 | This is asymmetric because if PushRedirects fails, then we don't execute
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| 281 | the command at all.
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| 282 |
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| 283 | Example:
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| 284 | { seq 3 > foo.txt; echo 4; } > bar.txt
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| 285 | """
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| 286 |
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| 287 | def __init__(self, shell_ex, num_redirects, err_out):
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| 288 | # type: (_Executor, int, List[error.IOError_OSError]) -> None
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| 289 | self.shell_ex = shell_ex
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| 290 | self.num_redirects = num_redirects
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| 291 | self.err_out = err_out
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| 292 |
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| 293 | def __enter__(self):
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| 294 | # type: () -> None
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| 295 | pass
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| 296 |
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| 297 | def __exit__(self, type, value, traceback):
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| 298 | # type: (Any, Any, Any) -> None
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| 299 | self.shell_ex.PopRedirects(self.num_redirects, self.err_out)
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| 300 |
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| 301 |
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| 302 | class ctx_ProcessSub(object):
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| 303 | """For waiting on processes started during word evaluation.
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| 304 |
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| 305 | Example:
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| 306 | diff <(seq 3) <(seq 4) > >(tac)
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| 307 | """
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| 308 |
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| 309 | def __init__(self, shell_ex, process_sub_status):
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| 310 | # type: (_Executor, StatusArray) -> None
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| 311 | shell_ex.PushProcessSub()
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| 312 | self.shell_ex = shell_ex
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| 313 | self.process_sub_status = process_sub_status
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| 314 |
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| 315 | def __enter__(self):
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| 316 | # type: () -> None
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| 317 | pass
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| 318 |
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| 319 | def __exit__(self, type, value, traceback):
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| 320 | # type: (Any, Any, Any) -> None
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| 321 |
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| 322 | # Wait and return array to set _process_sub_status
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| 323 | self.shell_ex.PopProcessSub(self.process_sub_status)
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| 324 |
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| 325 |
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| 326 | class ctx_FlushStdout(object):
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| 327 |
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| 328 | def __init__(self, err_out):
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| 329 | # type: (List[error.IOError_OSError]) -> None
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| 330 | self.err_out = err_out
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| 331 |
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| 332 | def __enter__(self):
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| 333 | # type: () -> None
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| 334 | pass
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| 335 |
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| 336 | def __exit__(self, type, value, traceback):
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| 337 | # type: (Any, Any, Any) -> None
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| 338 |
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| 339 | # Can't raise exception in destructor! So we append it to out param.
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| 340 | err = pyos.FlushStdout()
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| 341 | if err is not None:
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| 342 | self.err_out.append(err)
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