1 | """
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2 | mylib.py: Python stubs/interfaces that are reimplemented in C++, not directly
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3 | translated.
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4 | """
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5 | from __future__ import print_function
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6 |
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7 | try:
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8 | import cStringIO
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9 | except ImportError:
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10 | # Python 3 doesn't have cStringIO. Our yaks/ demo currently uses
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11 | # mycpp/mylib.py with Python 3.
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12 | cStringIO = None
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13 | import io
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14 |
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15 | import sys
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16 |
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17 | from pylib import collections_
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18 | try:
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19 | import posix_ as posix
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20 | except ImportError:
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21 | # Hack for tangled dependencies.
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22 | import os
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23 | posix = os
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24 |
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25 | from typing import (Tuple, List, Dict, Optional, Iterator, Any, TypeVar,
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26 | Generic, cast, TYPE_CHECKING)
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27 | if TYPE_CHECKING:
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28 | from mycpp import mops
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29 |
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30 | # For conditional translation
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31 | CPP = False
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32 | PYTHON = True
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33 |
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34 | # Use POSIX name directly
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35 | STDIN_FILENO = 0
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36 |
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37 |
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38 | def MaybeCollect():
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39 | # type: () -> None
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40 | pass
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41 |
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42 |
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43 | def PrintGcStats():
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44 | # type: () -> None
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45 | pass
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46 |
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47 |
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48 | def NewDict():
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49 | # type: () -> Dict[str, Any]
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50 | """Make dictionaries ordered in Python, e.g. for JSON.
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51 |
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52 | In C++, our Dict implementation should be ordered.
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53 | """
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54 | return collections_.OrderedDict()
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55 |
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56 |
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57 | def log(msg, *args):
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58 | # type: (str, *Any) -> None
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59 | """Print debug output to stderr."""
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60 | if args:
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61 | msg = msg % args
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62 | print(msg, file=sys.stderr)
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63 |
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64 |
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65 | def print_stderr(s):
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66 | # type: (str) -> None
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67 | """Print a message to stderr for the user.
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68 |
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69 | This should be used sparingly, since it doesn't have location info, like
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70 | ui.ErrorFormatter does. We use it to print fatal I/O errors that were only
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71 | caught at the top level.
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72 | """
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73 | print(s, file=sys.stderr)
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74 |
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75 |
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76 | #
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77 | # Byte Operations avoid excessive allocations with string algorithms
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78 | #
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79 |
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80 |
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81 | def ByteAt(s, i):
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82 | # type: (str, int) -> int
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83 | """i must be in bounds."""
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84 |
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85 | # This simplifies the C++ implementation
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86 | assert 0 <= i, 'No negative indices'
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87 | assert i < len(s), 'No negative indices'
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88 |
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89 | return ord(s[i])
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90 |
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91 |
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92 | def ByteEquals(byte, ch):
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93 | # type: (int, str) -> bool
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94 | assert len(ch) == 1, ch
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95 | assert 0 <= byte < 256, byte
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96 |
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97 | return byte == ord(ch)
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98 |
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99 |
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100 | def ByteInSet(byte, byte_set):
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101 | # type: (int, str) -> bool
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102 | assert 0 <= byte < 256, byte
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103 |
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104 | return chr(byte) in byte_set
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105 |
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106 |
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107 | def JoinBytes(byte_list):
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108 | # type: (List[int]) -> str
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109 |
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110 | return ''.join(chr(b) for b in byte_list)
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111 |
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112 |
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113 | #
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114 | # For SparseArray
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115 | #
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116 |
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117 |
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118 | def BigIntSort(keys):
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119 | # type: (List[mops.BigInt]) -> None
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120 | keys.sort(key=lambda big: big.i)
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121 |
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122 |
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123 | #
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124 | # Files
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125 | #
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126 |
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127 |
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128 | class LineReader:
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129 |
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130 | def readline(self):
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131 | # type: () -> str
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132 | raise NotImplementedError()
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133 |
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134 | def close(self):
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135 | # type: () -> None
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136 | raise NotImplementedError()
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137 |
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138 | def isatty(self):
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139 | # type: () -> bool
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140 | raise NotImplementedError()
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141 |
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142 |
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143 | if TYPE_CHECKING:
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144 |
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145 | class BufLineReader(LineReader):
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146 |
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147 | def __init__(self, s):
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148 | # type: (str) -> None
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149 | raise NotImplementedError()
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150 |
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151 | def open(path):
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152 | # type: (str) -> LineReader
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153 |
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154 | # TODO: should probably return mylib.File
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155 | # mylib.open() is currently only used in yaks/yaks_main and
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156 | # bin.osh_parse
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157 | raise NotImplementedError()
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158 |
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159 | else:
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160 | # Actual runtime
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161 | if cStringIO:
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162 | BufLineReader = cStringIO.StringIO
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163 | else: # Python 3
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164 | BufLineReader = io.StringIO
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165 |
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166 | open = open
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167 |
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168 |
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169 | class Writer:
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170 |
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171 | def write(self, s):
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172 | # type: (str) -> None
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173 | raise NotImplementedError()
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174 |
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175 | def flush(self):
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176 | # type: () -> None
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177 | raise NotImplementedError()
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178 |
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179 | def isatty(self):
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180 | # type: () -> bool
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181 | raise NotImplementedError()
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182 |
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183 | def close(self):
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184 | # type: () -> None
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185 | raise NotImplementedError()
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186 |
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187 |
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188 | class BufWriter(Writer):
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189 | """Mimic StringIO API, but add clear() so we can reuse objects.
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190 |
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191 | We can also add accelerators for directly writing numbers, to avoid
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192 | allocations when encoding JSON.
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193 | """
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194 |
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195 | def __init__(self):
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196 | # type: () -> None
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197 | self.parts = []
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198 |
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199 | def write(self, s):
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200 | # type: (str) -> None
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201 | self.parts.append(s)
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202 |
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203 | def isatty(self):
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204 | # type: () -> bool
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205 | return False
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206 |
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207 | def write_spaces(self, n):
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208 | # type: (int) -> None
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209 | """For JSON indenting. Avoid intermediate allocations in C++."""
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210 | self.parts.append(' ' * n)
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211 |
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212 | def getvalue(self):
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213 | # type: () -> str
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214 | return ''.join(self.parts)
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215 |
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216 | def clear(self):
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217 | # type: () -> None
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218 | del self.parts[:]
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219 |
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220 | def close(self):
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221 | # type: () -> None
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222 |
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223 | # No-op for now - we could invalidate write()?
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224 | pass
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225 |
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226 |
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227 | def Stdout():
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228 | # type: () -> Writer
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229 | return sys.stdout
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230 |
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231 |
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232 | def Stderr():
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233 | # type: () -> Writer
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234 | return sys.stderr
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235 |
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236 |
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237 | def Stdin():
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238 | # type: () -> LineReader
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239 | return sys.stdin
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240 |
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241 |
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242 | class switch(object):
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243 | """Translates to C switch on int.
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244 |
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245 | with switch(i) as case:
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246 | if case(42, 43):
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247 | print('hi')
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248 | elif case(99):
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249 | print('two')
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250 | else:
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251 | print('neither')
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252 | """
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253 |
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254 | def __init__(self, value):
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255 | # type: (int) -> None
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256 | self.value = value
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257 |
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258 | def __enter__(self):
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259 | # type: () -> switch
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260 | return self
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261 |
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262 | def __exit__(self, type, value, traceback):
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263 | # type: (Any, Any, Any) -> bool
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264 | return False # Allows a traceback to occur
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265 |
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266 | def __call__(self, *cases):
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267 | # type: (*Any) -> bool
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268 | return self.value in cases
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269 |
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270 |
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271 | class str_switch(object):
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272 | """Translates to fast dispatch on string length, then memcmp()."""
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273 |
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274 | def __init__(self, value):
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275 | # type: (str) -> None
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276 | self.value = value
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277 |
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278 | def __enter__(self):
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279 | # type: () -> switch
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280 | return self
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281 |
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282 | def __exit__(self, type, value, traceback):
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283 | # type: (Any, Any, Any) -> bool
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284 | return False # Allows a traceback to occur
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285 |
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286 | def __call__(self, *cases):
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287 | # type: (*Any) -> bool
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288 | return self.value in cases
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289 |
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290 |
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291 | class tagswitch(object):
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292 | """Translates to C switch(node->tag())"""
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293 |
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294 | def __init__(self, node):
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295 | # type: (Any) -> None
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296 | self.tag = node.tag()
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297 |
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298 | def __enter__(self):
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299 | # type: () -> tagswitch
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300 | return self
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301 |
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302 | def __exit__(self, type, value, traceback):
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303 | # type: (Any, Any, Any) -> bool
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304 | return False # Allows a traceback to occur
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305 |
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306 | def __call__(self, *cases):
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307 | # type: (*Any) -> bool
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308 | return self.tag in cases
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309 |
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310 |
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311 | if TYPE_CHECKING:
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312 | # Doesn't work
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313 | T = TypeVar('T')
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314 |
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315 | class StackArray(Generic[T]):
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316 |
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317 | def __init__(self):
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318 | self.items = [] # type: List[T]
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319 |
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320 | def append(self, item):
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321 | # type: (T) -> None
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322 | self.items.append(item)
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323 |
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324 | def pop(self):
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325 | # type: () -> T
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326 | return self.items.pop()
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327 |
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328 | # Doesn't work, this is only for primitive types
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329 | #StackArray = NewType('StackArray', list)
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330 |
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331 |
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332 | def MakeStackArray(item_type):
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333 | # type: (TypeVar) -> StackArray[item_type]
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334 | """
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335 | Convenience "constructor" used like this:
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336 |
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337 | myarray = MakeStackArray(int)
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338 |
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339 | The idiom could also be
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340 |
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341 | myarray = cast('StackArray[int]', [])
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342 |
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343 | But that's uglier.
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344 | """
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345 | return cast('StackArray[item_type]', [])
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346 |
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347 |
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348 | if TYPE_CHECKING:
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349 | K = TypeVar('K')
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350 | V = TypeVar('V')
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351 |
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352 |
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353 | def iteritems(d):
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354 | # type: (Dict[K, V]) -> Iterator[Tuple[K, V]]
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355 | """Make translation a bit easier."""
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356 | return d.iteritems()
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357 |
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358 |
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359 | def split_once(s, delim):
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360 | # type: (str, str) -> Tuple[str, Optional[str]]
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361 | """Easier to call than split(s, 1) because of tuple unpacking."""
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362 |
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363 | parts = s.split(delim, 1)
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364 | if len(parts) == 1:
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365 | no_str = None # type: Optional[str]
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366 | return s, no_str
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367 | else:
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368 | return parts[0], parts[1]
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369 |
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370 |
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371 | def hex_lower(i):
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372 | # type: (int) -> str
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373 | return '%x' % i
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374 |
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375 |
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376 | def dict_erase(d, key):
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377 | # type: (Dict[Any, Any], Any) -> None
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378 | """
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379 | Ensure that a key isn't in the Dict d. This makes C++ translation easier.
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380 | """
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381 | try:
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382 | del d[key]
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383 | except KeyError:
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384 | pass
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385 |
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386 |
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387 | def str_cmp(s1, s2):
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388 | # type: (str, str) -> int
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389 | if s1 == s2:
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390 | return 0
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391 | if s1 < s2:
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392 | return -1
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393 | else:
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394 | return 1
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395 |
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396 |
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397 | class UniqueObjects(object):
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398 | """A set of objects identified by their address in memory
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399 |
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400 | Python's id(obj) returns the address of any object. But we don't simply
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401 | implement it, because it requires a uint64_t on 64-bit systems, while mycpp
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402 | only supports 'int'.
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403 |
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404 | So we have a whole class.
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405 |
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406 | Should be used for:
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407 |
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408 | - Cycle detection when pretty printing, as Python's repr() does
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409 | - See CPython's Objects/object.c PyObject_Repr()
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410 | /* These methods are used to control infinite recursion in repr, str, print,
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411 | etc. Container objects that may recursively contain themselves,
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412 | e.g. builtin dictionaries and lists, should use Py_ReprEnter() and
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413 | Py_ReprLeave() to avoid infinite recursion.
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414 | */
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415 | - e.g. dictobject.c dict_repr() calls Py_ReprEnter() to print {...}
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416 | - In Python 2.7 a GLOBAL VAR is used
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417 |
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418 | - It also checks for STACK OVERFLOW
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419 |
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420 | - Packle serialization
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421 | """
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422 |
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423 | def __init__(self):
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424 | # 64-bit id() -> small integer ID
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425 | self.addresses = {} # type: Dict[int, int]
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426 |
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427 | def Contains(self, obj):
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428 | # type: (Any) -> bool
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429 | """ Convenience? """
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430 | return self.Get(obj) != -1
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431 |
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432 | def MaybeAdd(self, obj):
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433 | # type: (Any) -> None
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434 | """ Convenience? """
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435 |
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436 | # def AddNewObject(self, obj):
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437 | def Add(self, obj):
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438 | # type: (Any) -> None
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439 | """
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440 | Assert it isn't already there, and assign a new ID!
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441 |
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442 | # Lib/pickle does:
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443 |
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444 | self.memo[id(obj)] = memo_len, obj
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445 |
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446 | I guess that's the object ID and a void*
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447 |
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448 | Then it does:
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449 |
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450 | x = self.memo.get(id(obj))
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451 |
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452 | and
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453 |
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454 | # If the object is already in the memo, this means it is
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455 | # recursive. In this case, throw away everything we put on the
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456 | # stack, and fetch the object back from the memo.
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457 | if id(obj) in self.memo:
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458 | write(POP + self.get(self.memo[id(obj)][0]))
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459 |
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460 | BUT It only uses the numeric ID!
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461 | """
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462 | addr = id(obj)
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463 | assert addr not in self.addresses
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464 | self.addresses[addr] = len(self.addresses)
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465 |
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466 | def Get(self, obj):
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467 | # type: (Any) -> int
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468 | """
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469 | Returns unique ID assigned
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470 |
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471 | Returns -1 if it doesn't exist?
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472 | """
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473 | addr = id(obj)
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474 | return self.addresses.get(addr, -1)
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475 |
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476 | # Note: self.memo.clear() doesn't appear to be used
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477 |
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478 |
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479 | def probe(provider, name, *args):
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480 | # type: (str, str, Any) -> None
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481 | """Create a probe for use with profilers like linux perf and ebpf or dtrace."""
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482 | # Noop. Just a marker for mycpp to emit a DTRACE_PROBE()
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483 | return
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484 |
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485 |
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486 | class File:
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487 | """
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488 | TODO: This should define a read/write interface, and then LineReader() and
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489 | Writer() can possibly inherit it, with runtime assertions
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490 |
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491 | Then we allow downcasting from File -> LineReader, like we currently do in
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492 | C++ in gc_mylib.h.
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493 |
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494 | Inheritance can't express the structural Reader/Writer pattern of Go, which
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495 | would be better. I suppose we could use File* everywhere, but having
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496 | fine-grained types is nicer. And there will be very few casts.
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497 | """
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498 | pass
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