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1 | 1 | # revlogdeltas.py - Logic around delta computation for revlog |
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2 | 2 | # |
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3 | 3 | # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> |
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4 | 4 | # Copyright 2018 Octobus <contact@octobus.net> |
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5 | 5 | # |
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6 | 6 | # This software may be used and distributed according to the terms of the |
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7 | 7 | # GNU General Public License version 2 or any later version. |
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8 | 8 | """Helper class to compute deltas stored inside revlogs""" |
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9 | 9 | |
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10 | 10 | from __future__ import absolute_import |
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11 | 11 | |
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12 | 12 | import collections |
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13 | 13 | import heapq |
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14 | 14 | import struct |
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15 | 15 | |
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16 | 16 | # import stuff from node for others to import from revlog |
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17 | 17 | from ..node import ( |
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18 | 18 | nullrev, |
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19 | 19 | ) |
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20 | 20 | from ..i18n import _ |
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21 | 21 | |
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22 | 22 | from .constants import ( |
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23 | 23 | REVIDX_ISCENSORED, |
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24 | 24 | REVIDX_RAWTEXT_CHANGING_FLAGS, |
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25 | 25 | ) |
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26 | 26 | |
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27 | 27 | from ..thirdparty import ( |
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28 | 28 | attr, |
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29 | 29 | ) |
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30 | 30 | |
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31 | 31 | from .. import ( |
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32 | 32 | error, |
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33 | 33 | mdiff, |
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34 | 34 | ) |
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35 | 35 | |
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36 | 36 | # maximum <delta-chain-data>/<revision-text-length> ratio |
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37 | 37 | LIMIT_DELTA2TEXT = 2 |
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38 | 38 | |
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39 | 39 | class _testrevlog(object): |
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40 | 40 | """minimalist fake revlog to use in doctests""" |
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41 | 41 | |
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42 | 42 | def __init__(self, data, density=0.5, mingap=0): |
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43 | 43 | """data is an list of revision payload boundaries""" |
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44 | 44 | self._data = data |
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45 | 45 | self._srdensitythreshold = density |
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46 | 46 | self._srmingapsize = mingap |
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47 | 47 | |
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48 | 48 | def start(self, rev): |
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49 | 49 | if rev == 0: |
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50 | 50 | return 0 |
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51 | 51 | return self._data[rev - 1] |
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52 | 52 | |
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53 | 53 | def end(self, rev): |
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54 | 54 | return self._data[rev] |
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55 | 55 | |
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56 | 56 | def length(self, rev): |
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57 | 57 | return self.end(rev) - self.start(rev) |
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58 | 58 | |
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59 | 59 | def __len__(self): |
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60 | 60 | return len(self._data) |
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61 | 61 | |
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62 |
def slicechunk(revlog, revs, |
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62 | def slicechunk(revlog, revs, targetsize=None): | |
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63 | 63 | """slice revs to reduce the amount of unrelated data to be read from disk. |
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64 | 64 | |
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65 | 65 | ``revs`` is sliced into groups that should be read in one time. |
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66 | 66 | Assume that revs are sorted. |
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67 | 67 | |
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68 | 68 | The initial chunk is sliced until the overall density (payload/chunks-span |
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69 | 69 | ratio) is above `revlog._srdensitythreshold`. No gap smaller than |
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70 | 70 | `revlog._srmingapsize` is skipped. |
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71 | 71 | |
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72 | 72 | If `targetsize` is set, no chunk larger than `targetsize` will be yield. |
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73 | 73 | For consistency with other slicing choice, this limit won't go lower than |
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74 | 74 | `revlog._srmingapsize`. |
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75 | 75 | |
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76 | 76 | If individual revisions chunk are larger than this limit, they will still |
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77 | 77 | be raised individually. |
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78 | 78 | |
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79 | 79 | >>> revlog = _testrevlog([ |
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80 | 80 | ... 5, #00 (5) |
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81 | 81 | ... 10, #01 (5) |
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82 | 82 | ... 12, #02 (2) |
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83 | 83 | ... 12, #03 (empty) |
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84 | 84 | ... 27, #04 (15) |
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85 | 85 | ... 31, #05 (4) |
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86 | 86 | ... 31, #06 (empty) |
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87 | 87 | ... 42, #07 (11) |
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88 | 88 | ... 47, #08 (5) |
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89 | 89 | ... 47, #09 (empty) |
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90 | 90 | ... 48, #10 (1) |
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91 | 91 | ... 51, #11 (3) |
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92 | 92 | ... 74, #12 (23) |
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93 | 93 | ... 85, #13 (11) |
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94 | 94 | ... 86, #14 (1) |
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95 | 95 | ... 91, #15 (5) |
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96 | 96 | ... ]) |
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97 | 97 | |
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98 | 98 | >>> list(slicechunk(revlog, list(range(16)))) |
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99 | 99 | [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]] |
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100 | 100 | >>> list(slicechunk(revlog, [0, 15])) |
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101 | 101 | [[0], [15]] |
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102 | 102 | >>> list(slicechunk(revlog, [0, 11, 15])) |
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103 | 103 | [[0], [11], [15]] |
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104 | 104 | >>> list(slicechunk(revlog, [0, 11, 13, 15])) |
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105 | 105 | [[0], [11, 13, 15]] |
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106 | 106 | >>> list(slicechunk(revlog, [1, 2, 3, 5, 8, 10, 11, 14])) |
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107 | 107 | [[1, 2], [5, 8, 10, 11], [14]] |
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108 | 108 | |
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109 | 109 | Slicing with a maximum chunk size |
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110 | 110 | >>> list(slicechunk(revlog, [0, 11, 13, 15], targetsize=15)) |
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111 | 111 | [[0], [11], [13], [15]] |
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112 | 112 | >>> list(slicechunk(revlog, [0, 11, 13, 15], targetsize=20)) |
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113 | 113 | [[0], [11], [13, 15]] |
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114 | 114 | """ |
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115 | 115 | if targetsize is not None: |
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116 | 116 | targetsize = max(targetsize, revlog._srmingapsize) |
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117 | 117 | # targetsize should not be specified when evaluating delta candidates: |
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118 | 118 | # * targetsize is used to ensure we stay within specification when reading, |
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119 | # * deltainfo is used to pick are good delta chain when writing. | |
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120 | if not (deltainfo is None or targetsize is None): | |
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121 | msg = 'cannot use `targetsize` with a `deltainfo`' | |
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122 | raise error.ProgrammingError(msg) | |
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123 | 119 | for chunk in _slicechunktodensity(revlog, revs, |
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124 | deltainfo, | |
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125 | 120 | revlog._srdensitythreshold, |
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126 | 121 | revlog._srmingapsize): |
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127 | 122 | for subchunk in _slicechunktosize(revlog, chunk, targetsize): |
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128 | 123 | yield subchunk |
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129 | 124 | |
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130 | 125 | def _slicechunktosize(revlog, revs, targetsize=None): |
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131 | 126 | """slice revs to match the target size |
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132 | 127 | |
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133 | 128 | This is intended to be used on chunk that density slicing selected by that |
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134 | 129 | are still too large compared to the read garantee of revlog. This might |
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135 | 130 | happens when "minimal gap size" interrupted the slicing or when chain are |
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136 | 131 | built in a way that create large blocks next to each other. |
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137 | 132 | |
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138 | 133 | >>> revlog = _testrevlog([ |
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139 | 134 | ... 3, #0 (3) |
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140 | 135 | ... 5, #1 (2) |
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141 | 136 | ... 6, #2 (1) |
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142 | 137 | ... 8, #3 (2) |
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143 | 138 | ... 8, #4 (empty) |
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144 | 139 | ... 11, #5 (3) |
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145 | 140 | ... 12, #6 (1) |
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146 | 141 | ... 13, #7 (1) |
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147 | 142 | ... 14, #8 (1) |
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148 | 143 | ... ]) |
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149 | 144 | |
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150 | 145 | Cases where chunk is already small enough |
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151 | 146 | >>> list(_slicechunktosize(revlog, [0], 3)) |
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152 | 147 | [[0]] |
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153 | 148 | >>> list(_slicechunktosize(revlog, [6, 7], 3)) |
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154 | 149 | [[6, 7]] |
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155 | 150 | >>> list(_slicechunktosize(revlog, [0], None)) |
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156 | 151 | [[0]] |
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157 | 152 | >>> list(_slicechunktosize(revlog, [6, 7], None)) |
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158 | 153 | [[6, 7]] |
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159 | 154 | |
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160 | 155 | cases where we need actual slicing |
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161 | 156 | >>> list(_slicechunktosize(revlog, [0, 1], 3)) |
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162 | 157 | [[0], [1]] |
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163 | 158 | >>> list(_slicechunktosize(revlog, [1, 3], 3)) |
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164 | 159 | [[1], [3]] |
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165 | 160 | >>> list(_slicechunktosize(revlog, [1, 2, 3], 3)) |
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166 | 161 | [[1, 2], [3]] |
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167 | 162 | >>> list(_slicechunktosize(revlog, [3, 5], 3)) |
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168 | 163 | [[3], [5]] |
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169 | 164 | >>> list(_slicechunktosize(revlog, [3, 4, 5], 3)) |
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170 | 165 | [[3], [5]] |
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171 | 166 | >>> list(_slicechunktosize(revlog, [5, 6, 7, 8], 3)) |
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172 | 167 | [[5], [6, 7, 8]] |
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173 | 168 | >>> list(_slicechunktosize(revlog, [0, 1, 2, 3, 4, 5, 6, 7, 8], 3)) |
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174 | 169 | [[0], [1, 2], [3], [5], [6, 7, 8]] |
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175 | 170 | |
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176 | 171 | Case with too large individual chunk (must return valid chunk) |
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177 | 172 | >>> list(_slicechunktosize(revlog, [0, 1], 2)) |
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178 | 173 | [[0], [1]] |
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179 | 174 | >>> list(_slicechunktosize(revlog, [1, 3], 1)) |
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180 | 175 | [[1], [3]] |
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181 | 176 | >>> list(_slicechunktosize(revlog, [3, 4, 5], 2)) |
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182 | 177 | [[3], [5]] |
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183 | 178 | """ |
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184 | 179 | assert targetsize is None or 0 <= targetsize |
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185 | 180 | if targetsize is None or segmentspan(revlog, revs) <= targetsize: |
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186 | 181 | yield revs |
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187 | 182 | return |
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188 | 183 | |
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189 | 184 | startrevidx = 0 |
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190 | 185 | startdata = revlog.start(revs[0]) |
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191 | 186 | endrevidx = 0 |
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192 | 187 | iterrevs = enumerate(revs) |
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193 | 188 | next(iterrevs) # skip first rev. |
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194 | 189 | for idx, r in iterrevs: |
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195 | 190 | span = revlog.end(r) - startdata |
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196 | 191 | if span <= targetsize: |
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197 | 192 | endrevidx = idx |
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198 | 193 | else: |
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199 | 194 | chunk = _trimchunk(revlog, revs, startrevidx, endrevidx + 1) |
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200 | 195 | if chunk: |
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201 | 196 | yield chunk |
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202 | 197 | startrevidx = idx |
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203 | 198 | startdata = revlog.start(r) |
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204 | 199 | endrevidx = idx |
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205 | 200 | yield _trimchunk(revlog, revs, startrevidx) |
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206 | 201 | |
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207 |
def _slicechunktodensity(revlog, revs, |
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202 | def _slicechunktodensity(revlog, revs, targetdensity=0.5, | |
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208 | 203 | mingapsize=0): |
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209 | 204 | """slice revs to reduce the amount of unrelated data to be read from disk. |
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210 | 205 | |
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211 | 206 | ``revs`` is sliced into groups that should be read in one time. |
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212 | 207 | Assume that revs are sorted. |
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213 | 208 | |
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214 | ``deltainfo`` is a _deltainfo instance of a revision that we would append | |
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215 | to the top of the revlog. | |
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216 | ||
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217 | 209 | The initial chunk is sliced until the overall density (payload/chunks-span |
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218 | 210 | ratio) is above `targetdensity`. No gap smaller than `mingapsize` is |
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219 | 211 | skipped. |
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220 | 212 | |
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221 | 213 | >>> revlog = _testrevlog([ |
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222 | 214 | ... 5, #00 (5) |
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223 | 215 | ... 10, #01 (5) |
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224 | 216 | ... 12, #02 (2) |
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225 | 217 | ... 12, #03 (empty) |
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226 | 218 | ... 27, #04 (15) |
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227 | 219 | ... 31, #05 (4) |
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228 | 220 | ... 31, #06 (empty) |
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229 | 221 | ... 42, #07 (11) |
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230 | 222 | ... 47, #08 (5) |
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231 | 223 | ... 47, #09 (empty) |
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232 | 224 | ... 48, #10 (1) |
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233 | 225 | ... 51, #11 (3) |
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234 | 226 | ... 74, #12 (23) |
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235 | 227 | ... 85, #13 (11) |
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236 | 228 | ... 86, #14 (1) |
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237 | 229 | ... 91, #15 (5) |
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238 | 230 | ... ]) |
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239 | 231 | |
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240 | 232 | >>> list(_slicechunktodensity(revlog, list(range(16)))) |
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241 | 233 | [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]] |
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242 | 234 | >>> list(_slicechunktodensity(revlog, [0, 15])) |
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243 | 235 | [[0], [15]] |
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244 | 236 | >>> list(_slicechunktodensity(revlog, [0, 11, 15])) |
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245 | 237 | [[0], [11], [15]] |
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246 | 238 | >>> list(_slicechunktodensity(revlog, [0, 11, 13, 15])) |
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247 | 239 | [[0], [11, 13, 15]] |
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248 | 240 | >>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14])) |
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249 | 241 | [[1, 2], [5, 8, 10, 11], [14]] |
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250 | 242 | >>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14], |
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251 | 243 | ... mingapsize=20)) |
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252 | 244 | [[1, 2, 3, 5, 8, 10, 11], [14]] |
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253 | 245 | >>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14], |
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254 | 246 | ... targetdensity=0.95)) |
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255 | 247 | [[1, 2], [5], [8, 10, 11], [14]] |
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256 | 248 | >>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14], |
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257 | 249 | ... targetdensity=0.95, mingapsize=12)) |
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258 | 250 | [[1, 2], [5, 8, 10, 11], [14]] |
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259 | 251 | """ |
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260 | 252 | start = revlog.start |
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261 | 253 | length = revlog.length |
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262 | 254 | |
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263 | 255 | if len(revs) <= 1: |
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264 | 256 | yield revs |
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265 | 257 | return |
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266 | 258 | |
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267 | nextrev = len(revlog) | |
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268 | nextoffset = revlog.end(nextrev - 1) | |
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269 | ||
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270 | if deltainfo is None: | |
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271 | deltachainspan = segmentspan(revlog, revs) | |
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272 | chainpayload = sum(length(r) for r in revs) | |
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273 | else: | |
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274 | deltachainspan = deltainfo.distance | |
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275 | chainpayload = deltainfo.compresseddeltalen | |
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259 | deltachainspan = segmentspan(revlog, revs) | |
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260 | chainpayload = sum(length(r) for r in revs) | |
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276 | 261 | |
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277 | 262 | if deltachainspan < mingapsize: |
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278 | 263 | yield revs |
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279 | 264 | return |
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280 | 265 | |
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281 | 266 | readdata = deltachainspan |
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282 | 267 | |
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283 | 268 | if deltachainspan: |
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284 | 269 | density = chainpayload / float(deltachainspan) |
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285 | 270 | else: |
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286 | 271 | density = 1.0 |
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287 | 272 | |
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288 | 273 | if density >= targetdensity: |
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289 | 274 | yield revs |
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290 | 275 | return |
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291 | 276 | |
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292 | if deltainfo is not None and deltainfo.deltalen: | |
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293 | revs = list(revs) | |
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294 | revs.append(nextrev) | |
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295 | ||
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296 | 277 | # Store the gaps in a heap to have them sorted by decreasing size |
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297 | 278 | gapsheap = [] |
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298 | 279 | heapq.heapify(gapsheap) |
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299 | 280 | prevend = None |
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300 | 281 | for i, rev in enumerate(revs): |
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301 |
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302 |
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303 | revlen = length(rev) | |
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304 | else: | |
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305 | revstart = nextoffset | |
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306 | revlen = deltainfo.deltalen | |
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282 | revstart = start(rev) | |
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283 | revlen = length(rev) | |
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307 | 284 | |
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308 | 285 | # Skip empty revisions to form larger holes |
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309 | 286 | if revlen == 0: |
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310 | 287 | continue |
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311 | 288 | |
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312 | 289 | if prevend is not None: |
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313 | 290 | gapsize = revstart - prevend |
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314 | 291 | # only consider holes that are large enough |
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315 | 292 | if gapsize > mingapsize: |
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316 | 293 | heapq.heappush(gapsheap, (-gapsize, i)) |
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317 | 294 | |
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318 | 295 | prevend = revstart + revlen |
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319 | 296 | |
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320 | 297 | # Collect the indices of the largest holes until the density is acceptable |
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321 | 298 | indicesheap = [] |
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322 | 299 | heapq.heapify(indicesheap) |
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323 | 300 | while gapsheap and density < targetdensity: |
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324 | 301 | oppgapsize, gapidx = heapq.heappop(gapsheap) |
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325 | 302 | |
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326 | 303 | heapq.heappush(indicesheap, gapidx) |
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327 | 304 | |
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328 | 305 | # the gap sizes are stored as negatives to be sorted decreasingly |
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329 | 306 | # by the heap |
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330 | 307 | readdata -= (-oppgapsize) |
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331 | 308 | if readdata > 0: |
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332 | 309 | density = chainpayload / float(readdata) |
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333 | 310 | else: |
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334 | 311 | density = 1.0 |
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335 | 312 | |
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336 | 313 | # Cut the revs at collected indices |
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337 | 314 | previdx = 0 |
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338 | 315 | while indicesheap: |
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339 | 316 | idx = heapq.heappop(indicesheap) |
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340 | 317 | |
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341 | 318 | chunk = _trimchunk(revlog, revs, previdx, idx) |
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342 | 319 | if chunk: |
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343 | 320 | yield chunk |
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344 | 321 | |
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345 | 322 | previdx = idx |
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346 | 323 | |
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347 | 324 | chunk = _trimchunk(revlog, revs, previdx) |
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348 | 325 | if chunk: |
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349 | 326 | yield chunk |
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350 | 327 | |
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351 | 328 | def _trimchunk(revlog, revs, startidx, endidx=None): |
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352 | 329 | """returns revs[startidx:endidx] without empty trailing revs |
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353 | 330 | |
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354 | 331 | Doctest Setup |
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355 | 332 | >>> revlog = _testrevlog([ |
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356 | 333 | ... 5, #0 |
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357 | 334 | ... 10, #1 |
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358 | 335 | ... 12, #2 |
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359 | 336 | ... 12, #3 (empty) |
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360 | 337 | ... 17, #4 |
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361 | 338 | ... 21, #5 |
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362 | 339 | ... 21, #6 (empty) |
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363 | 340 | ... ]) |
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364 | 341 | |
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365 | 342 | Contiguous cases: |
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366 | 343 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0) |
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367 | 344 | [0, 1, 2, 3, 4, 5] |
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368 | 345 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0, 5) |
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369 | 346 | [0, 1, 2, 3, 4] |
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370 | 347 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0, 4) |
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371 | 348 | [0, 1, 2] |
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372 | 349 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 2, 4) |
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373 | 350 | [2] |
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374 | 351 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 3) |
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375 | 352 | [3, 4, 5] |
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376 | 353 | >>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 3, 5) |
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377 | 354 | [3, 4] |
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378 | 355 | |
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379 | 356 | Discontiguous cases: |
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380 | 357 | >>> _trimchunk(revlog, [1, 3, 5, 6], 0) |
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381 | 358 | [1, 3, 5] |
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382 | 359 | >>> _trimchunk(revlog, [1, 3, 5, 6], 0, 2) |
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383 | 360 | [1] |
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384 | 361 | >>> _trimchunk(revlog, [1, 3, 5, 6], 1, 3) |
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385 | 362 | [3, 5] |
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386 | 363 | >>> _trimchunk(revlog, [1, 3, 5, 6], 1) |
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387 | 364 | [3, 5] |
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388 | 365 | """ |
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389 | 366 | length = revlog.length |
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390 | 367 | |
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391 | 368 | if endidx is None: |
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392 | 369 | endidx = len(revs) |
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393 | 370 | |
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394 | 371 | # If we have a non-emtpy delta candidate, there are nothing to trim |
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395 | 372 | if revs[endidx - 1] < len(revlog): |
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396 | 373 | # Trim empty revs at the end, except the very first revision of a chain |
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397 | 374 | while (endidx > 1 |
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398 | 375 | and endidx > startidx |
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399 | 376 | and length(revs[endidx - 1]) == 0): |
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400 | 377 | endidx -= 1 |
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401 | 378 | |
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402 | 379 | return revs[startidx:endidx] |
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403 | 380 | |
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404 | 381 | def segmentspan(revlog, revs, deltainfo=None): |
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405 | 382 | """Get the byte span of a segment of revisions |
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406 | 383 | |
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407 | 384 | revs is a sorted array of revision numbers |
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408 | 385 | |
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409 | 386 | >>> revlog = _testrevlog([ |
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410 | 387 | ... 5, #0 |
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411 | 388 | ... 10, #1 |
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412 | 389 | ... 12, #2 |
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413 | 390 | ... 12, #3 (empty) |
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414 | 391 | ... 17, #4 |
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415 | 392 | ... ]) |
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416 | 393 | |
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417 | 394 | >>> segmentspan(revlog, [0, 1, 2, 3, 4]) |
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418 | 395 | 17 |
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419 | 396 | >>> segmentspan(revlog, [0, 4]) |
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420 | 397 | 17 |
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421 | 398 | >>> segmentspan(revlog, [3, 4]) |
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422 | 399 | 5 |
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423 | 400 | >>> segmentspan(revlog, [1, 2, 3,]) |
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424 | 401 | 7 |
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425 | 402 | >>> segmentspan(revlog, [1, 3]) |
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426 | 403 | 7 |
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427 | 404 | """ |
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428 | 405 | if not revs: |
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429 | 406 | return 0 |
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430 | 407 | if deltainfo is not None and len(revlog) <= revs[-1]: |
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431 | 408 | if len(revs) == 1: |
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432 | 409 | return deltainfo.deltalen |
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433 | 410 | offset = revlog.end(len(revlog) - 1) |
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434 | 411 | end = deltainfo.deltalen + offset |
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435 | 412 | else: |
|
436 | 413 | end = revlog.end(revs[-1]) |
|
437 | 414 | return end - revlog.start(revs[0]) |
|
438 | 415 | |
|
439 | 416 | def _textfromdelta(fh, revlog, baserev, delta, p1, p2, flags, expectednode): |
|
440 | 417 | """build full text from a (base, delta) pair and other metadata""" |
|
441 | 418 | # special case deltas which replace entire base; no need to decode |
|
442 | 419 | # base revision. this neatly avoids censored bases, which throw when |
|
443 | 420 | # they're decoded. |
|
444 | 421 | hlen = struct.calcsize(">lll") |
|
445 | 422 | if delta[:hlen] == mdiff.replacediffheader(revlog.rawsize(baserev), |
|
446 | 423 | len(delta) - hlen): |
|
447 | 424 | fulltext = delta[hlen:] |
|
448 | 425 | else: |
|
449 | 426 | # deltabase is rawtext before changed by flag processors, which is |
|
450 | 427 | # equivalent to non-raw text |
|
451 | 428 | basetext = revlog.revision(baserev, _df=fh, raw=False) |
|
452 | 429 | fulltext = mdiff.patch(basetext, delta) |
|
453 | 430 | |
|
454 | 431 | try: |
|
455 | 432 | res = revlog._processflags(fulltext, flags, 'read', raw=True) |
|
456 | 433 | fulltext, validatehash = res |
|
457 | 434 | if validatehash: |
|
458 | 435 | revlog.checkhash(fulltext, expectednode, p1=p1, p2=p2) |
|
459 | 436 | if flags & REVIDX_ISCENSORED: |
|
460 | 437 | raise error.StorageError(_('node %s is not censored') % |
|
461 | 438 | expectednode) |
|
462 | 439 | except error.CensoredNodeError: |
|
463 | 440 | # must pass the censored index flag to add censored revisions |
|
464 | 441 | if not flags & REVIDX_ISCENSORED: |
|
465 | 442 | raise |
|
466 | 443 | return fulltext |
|
467 | 444 | |
|
468 | 445 | @attr.s(slots=True, frozen=True) |
|
469 | 446 | class _deltainfo(object): |
|
470 | 447 | distance = attr.ib() |
|
471 | 448 | deltalen = attr.ib() |
|
472 | 449 | data = attr.ib() |
|
473 | 450 | base = attr.ib() |
|
474 | 451 | chainbase = attr.ib() |
|
475 | 452 | chainlen = attr.ib() |
|
476 | 453 | compresseddeltalen = attr.ib() |
|
477 | 454 | snapshotdepth = attr.ib() |
|
478 | 455 | |
|
479 | 456 | def isgooddeltainfo(revlog, deltainfo, revinfo): |
|
480 | 457 | """Returns True if the given delta is good. Good means that it is within |
|
481 | 458 | the disk span, disk size, and chain length bounds that we know to be |
|
482 | 459 | performant.""" |
|
483 | 460 | if deltainfo is None: |
|
484 | 461 | return False |
|
485 | 462 | |
|
486 | 463 | # - 'deltainfo.distance' is the distance from the base revision -- |
|
487 | 464 | # bounding it limits the amount of I/O we need to do. |
|
488 | 465 | # - 'deltainfo.compresseddeltalen' is the sum of the total size of |
|
489 | 466 | # deltas we need to apply -- bounding it limits the amount of CPU |
|
490 | 467 | # we consume. |
|
491 | 468 | |
|
492 | 469 | textlen = revinfo.textlen |
|
493 | 470 | defaultmax = textlen * 4 |
|
494 | 471 | maxdist = revlog._maxdeltachainspan |
|
495 | 472 | if not maxdist: |
|
496 | 473 | maxdist = deltainfo.distance # ensure the conditional pass |
|
497 | 474 | maxdist = max(maxdist, defaultmax) |
|
498 | 475 | |
|
499 | 476 | # Bad delta from read span: |
|
500 | 477 | # |
|
501 | 478 | # If the span of data read is larger than the maximum allowed. |
|
502 | 479 | # |
|
503 | 480 | # In the sparse-revlog case, we rely on the associated "sparse reading" |
|
504 | 481 | # to avoid issue related to the span of data. In theory, it would be |
|
505 | 482 | # possible to build pathological revlog where delta pattern would lead |
|
506 | 483 | # to too many reads. However, they do not happen in practice at all. So |
|
507 | 484 | # we skip the span check entirely. |
|
508 | 485 | if not revlog._sparserevlog and maxdist < deltainfo.distance: |
|
509 | 486 | return False |
|
510 | 487 | |
|
511 | 488 | # Bad delta from new delta size: |
|
512 | 489 | # |
|
513 | 490 | # If the delta size is larger than the target text, storing the |
|
514 | 491 | # delta will be inefficient. |
|
515 | 492 | if textlen < deltainfo.deltalen: |
|
516 | 493 | return False |
|
517 | 494 | |
|
518 | 495 | # Bad delta from cumulated payload size: |
|
519 | 496 | # |
|
520 | 497 | # If the sum of delta get larger than K * target text length. |
|
521 | 498 | if textlen * LIMIT_DELTA2TEXT < deltainfo.compresseddeltalen: |
|
522 | 499 | return False |
|
523 | 500 | |
|
524 | 501 | # Bad delta from chain length: |
|
525 | 502 | # |
|
526 | 503 | # If the number of delta in the chain gets too high. |
|
527 | 504 | if (revlog._maxchainlen |
|
528 | 505 | and revlog._maxchainlen < deltainfo.chainlen): |
|
529 | 506 | return False |
|
530 | 507 | |
|
531 | 508 | # bad delta from intermediate snapshot size limit |
|
532 | 509 | # |
|
533 | 510 | # If an intermediate snapshot size is higher than the limit. The |
|
534 | 511 | # limit exist to prevent endless chain of intermediate delta to be |
|
535 | 512 | # created. |
|
536 | 513 | if (deltainfo.snapshotdepth is not None and |
|
537 | 514 | (textlen >> deltainfo.snapshotdepth) < deltainfo.deltalen): |
|
538 | 515 | return False |
|
539 | 516 | |
|
540 | 517 | # bad delta if new intermediate snapshot is larger than the previous |
|
541 | 518 | # snapshot |
|
542 | 519 | if (deltainfo.snapshotdepth |
|
543 | 520 | and revlog.length(deltainfo.base) < deltainfo.deltalen): |
|
544 | 521 | return False |
|
545 | 522 | |
|
546 | 523 | return True |
|
547 | 524 | |
|
548 | 525 | def _candidategroups(revlog, textlen, p1, p2, cachedelta): |
|
549 | 526 | """Provides group of revision to be tested as delta base |
|
550 | 527 | |
|
551 | 528 | This top level function focus on emitting groups with unique and worthwhile |
|
552 | 529 | content. See _raw_candidate_groups for details about the group order. |
|
553 | 530 | """ |
|
554 | 531 | # should we try to build a delta? |
|
555 | 532 | if not (len(revlog) and revlog._storedeltachains): |
|
556 | 533 | yield None |
|
557 | 534 | return |
|
558 | 535 | |
|
559 | 536 | deltalength = revlog.length |
|
560 | 537 | deltaparent = revlog.deltaparent |
|
561 | 538 | good = None |
|
562 | 539 | |
|
563 | 540 | deltas_limit = textlen * LIMIT_DELTA2TEXT |
|
564 | 541 | |
|
565 | 542 | tested = set([nullrev]) |
|
566 | 543 | candidates = _refinedgroups(revlog, p1, p2, cachedelta) |
|
567 | 544 | while True: |
|
568 | 545 | temptative = candidates.send(good) |
|
569 | 546 | if temptative is None: |
|
570 | 547 | break |
|
571 | 548 | group = [] |
|
572 | 549 | for rev in temptative: |
|
573 | 550 | # skip over empty delta (no need to include them in a chain) |
|
574 | 551 | while (revlog._generaldelta |
|
575 | 552 | and not (rev == nullrev |
|
576 | 553 | or rev in tested |
|
577 | 554 | or deltalength(rev))): |
|
578 | 555 | tested.add(rev) |
|
579 | 556 | rev = deltaparent(rev) |
|
580 | 557 | # filter out revision we tested already |
|
581 | 558 | if rev in tested: |
|
582 | 559 | continue |
|
583 | 560 | tested.add(rev) |
|
584 | 561 | # filter out delta base that will never produce good delta |
|
585 | 562 | if deltas_limit < revlog.length(rev): |
|
586 | 563 | continue |
|
587 | 564 | # no need to try a delta against nullrev, this will be done as a |
|
588 | 565 | # last resort. |
|
589 | 566 | if rev == nullrev: |
|
590 | 567 | continue |
|
591 | 568 | # no delta for rawtext-changing revs (see "candelta" for why) |
|
592 | 569 | if revlog.flags(rev) & REVIDX_RAWTEXT_CHANGING_FLAGS: |
|
593 | 570 | continue |
|
594 | 571 | group.append(rev) |
|
595 | 572 | if group: |
|
596 | 573 | # XXX: in the sparse revlog case, group can become large, |
|
597 | 574 | # impacting performances. Some bounding or slicing mecanism |
|
598 | 575 | # would help to reduce this impact. |
|
599 | 576 | good = yield tuple(group) |
|
600 | 577 | yield None |
|
601 | 578 | |
|
602 | 579 | def _findsnapshots(revlog, cache, start_rev): |
|
603 | 580 | """find snapshot from start_rev to tip""" |
|
604 | 581 | deltaparent = revlog.deltaparent |
|
605 | 582 | issnapshot = revlog.issnapshot |
|
606 | 583 | for rev in revlog.revs(start_rev): |
|
607 | 584 | if issnapshot(rev): |
|
608 | 585 | cache[deltaparent(rev)].append(rev) |
|
609 | 586 | |
|
610 | 587 | def _refinedgroups(revlog, p1, p2, cachedelta): |
|
611 | 588 | good = None |
|
612 | 589 | # First we try to reuse a the delta contained in the bundle. |
|
613 | 590 | # (or from the source revlog) |
|
614 | 591 | # |
|
615 | 592 | # This logic only applies to general delta repositories and can be disabled |
|
616 | 593 | # through configuration. Disabling reuse source delta is useful when |
|
617 | 594 | # we want to make sure we recomputed "optimal" deltas. |
|
618 | 595 | if cachedelta and revlog._generaldelta and revlog._lazydeltabase: |
|
619 | 596 | # Assume what we received from the server is a good choice |
|
620 | 597 | # build delta will reuse the cache |
|
621 | 598 | good = yield (cachedelta[0],) |
|
622 | 599 | if good is not None: |
|
623 | 600 | yield None |
|
624 | 601 | return |
|
625 | 602 | for candidates in _rawgroups(revlog, p1, p2, cachedelta): |
|
626 | 603 | good = yield candidates |
|
627 | 604 | if good is not None: |
|
628 | 605 | break |
|
629 | 606 | |
|
630 | 607 | # If sparse revlog is enabled, we can try to refine the available deltas |
|
631 | 608 | if not revlog._sparserevlog: |
|
632 | 609 | yield None |
|
633 | 610 | return |
|
634 | 611 | |
|
635 | 612 | # if we have a refinable value, try to refine it |
|
636 | 613 | if good is not None and good not in (p1, p2) and revlog.issnapshot(good): |
|
637 | 614 | # refine snapshot down |
|
638 | 615 | previous = None |
|
639 | 616 | while previous != good: |
|
640 | 617 | previous = good |
|
641 | 618 | base = revlog.deltaparent(good) |
|
642 | 619 | if base == nullrev: |
|
643 | 620 | break |
|
644 | 621 | good = yield (base,) |
|
645 | 622 | # refine snapshot up |
|
646 | 623 | # |
|
647 | 624 | # XXX the _findsnapshots call can be expensive and is "duplicated" with |
|
648 | 625 | # the one done in `_rawgroups`. Once we start working on performance, |
|
649 | 626 | # we should make the two logics share this computation. |
|
650 | 627 | snapshots = collections.defaultdict(list) |
|
651 | 628 | _findsnapshots(revlog, snapshots, good + 1) |
|
652 | 629 | previous = None |
|
653 | 630 | while good != previous: |
|
654 | 631 | previous = good |
|
655 | 632 | children = tuple(sorted(c for c in snapshots[good])) |
|
656 | 633 | good = yield children |
|
657 | 634 | |
|
658 | 635 | # we have found nothing |
|
659 | 636 | yield None |
|
660 | 637 | |
|
661 | 638 | def _rawgroups(revlog, p1, p2, cachedelta): |
|
662 | 639 | """Provides group of revision to be tested as delta base |
|
663 | 640 | |
|
664 | 641 | This lower level function focus on emitting delta theorically interresting |
|
665 | 642 | without looking it any practical details. |
|
666 | 643 | |
|
667 | 644 | The group order aims at providing fast or small candidates first. |
|
668 | 645 | """ |
|
669 | 646 | gdelta = revlog._generaldelta |
|
670 | 647 | sparse = revlog._sparserevlog |
|
671 | 648 | curr = len(revlog) |
|
672 | 649 | prev = curr - 1 |
|
673 | 650 | deltachain = lambda rev: revlog._deltachain(rev)[0] |
|
674 | 651 | |
|
675 | 652 | if gdelta: |
|
676 | 653 | # exclude already lazy tested base if any |
|
677 | 654 | parents = [p for p in (p1, p2) if p != nullrev] |
|
678 | 655 | |
|
679 | 656 | if not revlog._deltabothparents and len(parents) == 2: |
|
680 | 657 | parents.sort() |
|
681 | 658 | # To minimize the chance of having to build a fulltext, |
|
682 | 659 | # pick first whichever parent is closest to us (max rev) |
|
683 | 660 | yield (parents[1],) |
|
684 | 661 | # then the other one (min rev) if the first did not fit |
|
685 | 662 | yield (parents[0],) |
|
686 | 663 | elif len(parents) > 0: |
|
687 | 664 | # Test all parents (1 or 2), and keep the best candidate |
|
688 | 665 | yield parents |
|
689 | 666 | |
|
690 | 667 | if sparse and parents: |
|
691 | 668 | snapshots = collections.defaultdict(list) # map: base-rev: snapshot-rev |
|
692 | 669 | # See if we can use an existing snapshot in the parent chains to use as |
|
693 | 670 | # a base for a new intermediate-snapshot |
|
694 | 671 | # |
|
695 | 672 | # search for snapshot in parents delta chain |
|
696 | 673 | # map: snapshot-level: snapshot-rev |
|
697 | 674 | parents_snaps = collections.defaultdict(set) |
|
698 | 675 | candidate_chains = [deltachain(p) for p in parents] |
|
699 | 676 | for chain in candidate_chains: |
|
700 | 677 | for idx, s in enumerate(chain): |
|
701 | 678 | if not revlog.issnapshot(s): |
|
702 | 679 | break |
|
703 | 680 | parents_snaps[idx].add(s) |
|
704 | 681 | snapfloor = min(parents_snaps[0]) + 1 |
|
705 | 682 | _findsnapshots(revlog, snapshots, snapfloor) |
|
706 | 683 | # search for the highest "unrelated" revision |
|
707 | 684 | # |
|
708 | 685 | # Adding snapshots used by "unrelated" revision increase the odd we |
|
709 | 686 | # reuse an independant, yet better snapshot chain. |
|
710 | 687 | # |
|
711 | 688 | # XXX instead of building a set of revisions, we could lazily enumerate |
|
712 | 689 | # over the chains. That would be more efficient, however we stick to |
|
713 | 690 | # simple code for now. |
|
714 | 691 | all_revs = set() |
|
715 | 692 | for chain in candidate_chains: |
|
716 | 693 | all_revs.update(chain) |
|
717 | 694 | other = None |
|
718 | 695 | for r in revlog.revs(prev, snapfloor): |
|
719 | 696 | if r not in all_revs: |
|
720 | 697 | other = r |
|
721 | 698 | break |
|
722 | 699 | if other is not None: |
|
723 | 700 | # To avoid unfair competition, we won't use unrelated intermediate |
|
724 | 701 | # snapshot that are deeper than the ones from the parent delta |
|
725 | 702 | # chain. |
|
726 | 703 | max_depth = max(parents_snaps.keys()) |
|
727 | 704 | chain = deltachain(other) |
|
728 | 705 | for idx, s in enumerate(chain): |
|
729 | 706 | if s < snapfloor: |
|
730 | 707 | continue |
|
731 | 708 | if max_depth < idx: |
|
732 | 709 | break |
|
733 | 710 | if not revlog.issnapshot(s): |
|
734 | 711 | break |
|
735 | 712 | parents_snaps[idx].add(s) |
|
736 | 713 | # Test them as possible intermediate snapshot base |
|
737 | 714 | # We test them from highest to lowest level. High level one are more |
|
738 | 715 | # likely to result in small delta |
|
739 | 716 | floor = None |
|
740 | 717 | for idx, snaps in sorted(parents_snaps.items(), reverse=True): |
|
741 | 718 | siblings = set() |
|
742 | 719 | for s in snaps: |
|
743 | 720 | siblings.update(snapshots[s]) |
|
744 | 721 | # Before considering making a new intermediate snapshot, we check |
|
745 | 722 | # if an existing snapshot, children of base we consider, would be |
|
746 | 723 | # suitable. |
|
747 | 724 | # |
|
748 | 725 | # It give a change to reuse a delta chain "unrelated" to the |
|
749 | 726 | # current revision instead of starting our own. Without such |
|
750 | 727 | # re-use, topological branches would keep reopening new chains. |
|
751 | 728 | # Creating more and more snapshot as the repository grow. |
|
752 | 729 | |
|
753 | 730 | if floor is not None: |
|
754 | 731 | # We only do this for siblings created after the one in our |
|
755 | 732 | # parent's delta chain. Those created before has less chances |
|
756 | 733 | # to be valid base since our ancestors had to create a new |
|
757 | 734 | # snapshot. |
|
758 | 735 | siblings = [r for r in siblings if floor < r] |
|
759 | 736 | yield tuple(sorted(siblings)) |
|
760 | 737 | # then test the base from our parent's delta chain. |
|
761 | 738 | yield tuple(sorted(snaps)) |
|
762 | 739 | floor = min(snaps) |
|
763 | 740 | # No suitable base found in the parent chain, search if any full |
|
764 | 741 | # snapshots emitted since parent's base would be a suitable base for an |
|
765 | 742 | # intermediate snapshot. |
|
766 | 743 | # |
|
767 | 744 | # It give a chance to reuse a delta chain unrelated to the current |
|
768 | 745 | # revisions instead of starting our own. Without such re-use, |
|
769 | 746 | # topological branches would keep reopening new full chains. Creating |
|
770 | 747 | # more and more snapshot as the repository grow. |
|
771 | 748 | yield tuple(snapshots[nullrev]) |
|
772 | 749 | |
|
773 | 750 | if not sparse: |
|
774 | 751 | # other approach failed try against prev to hopefully save us a |
|
775 | 752 | # fulltext. |
|
776 | 753 | yield (prev,) |
|
777 | 754 | |
|
778 | 755 | class deltacomputer(object): |
|
779 | 756 | def __init__(self, revlog): |
|
780 | 757 | self.revlog = revlog |
|
781 | 758 | |
|
782 | 759 | def buildtext(self, revinfo, fh): |
|
783 | 760 | """Builds a fulltext version of a revision |
|
784 | 761 | |
|
785 | 762 | revinfo: _revisioninfo instance that contains all needed info |
|
786 | 763 | fh: file handle to either the .i or the .d revlog file, |
|
787 | 764 | depending on whether it is inlined or not |
|
788 | 765 | """ |
|
789 | 766 | btext = revinfo.btext |
|
790 | 767 | if btext[0] is not None: |
|
791 | 768 | return btext[0] |
|
792 | 769 | |
|
793 | 770 | revlog = self.revlog |
|
794 | 771 | cachedelta = revinfo.cachedelta |
|
795 | 772 | baserev = cachedelta[0] |
|
796 | 773 | delta = cachedelta[1] |
|
797 | 774 | |
|
798 | 775 | fulltext = btext[0] = _textfromdelta(fh, revlog, baserev, delta, |
|
799 | 776 | revinfo.p1, revinfo.p2, |
|
800 | 777 | revinfo.flags, revinfo.node) |
|
801 | 778 | return fulltext |
|
802 | 779 | |
|
803 | 780 | def _builddeltadiff(self, base, revinfo, fh): |
|
804 | 781 | revlog = self.revlog |
|
805 | 782 | t = self.buildtext(revinfo, fh) |
|
806 | 783 | if revlog.iscensored(base): |
|
807 | 784 | # deltas based on a censored revision must replace the |
|
808 | 785 | # full content in one patch, so delta works everywhere |
|
809 | 786 | header = mdiff.replacediffheader(revlog.rawsize(base), len(t)) |
|
810 | 787 | delta = header + t |
|
811 | 788 | else: |
|
812 | 789 | ptext = revlog.revision(base, _df=fh, raw=True) |
|
813 | 790 | delta = mdiff.textdiff(ptext, t) |
|
814 | 791 | |
|
815 | 792 | return delta |
|
816 | 793 | |
|
817 | 794 | def _builddeltainfo(self, revinfo, base, fh): |
|
818 | 795 | # can we use the cached delta? |
|
819 | 796 | delta = None |
|
820 | 797 | if revinfo.cachedelta: |
|
821 | 798 | cachebase, cachediff = revinfo.cachedelta |
|
822 | 799 | #check if the diff still apply |
|
823 | 800 | currentbase = cachebase |
|
824 | 801 | while (currentbase != nullrev |
|
825 | 802 | and currentbase != base |
|
826 | 803 | and self.revlog.length(currentbase) == 0): |
|
827 | 804 | currentbase = self.revlog.deltaparent(currentbase) |
|
828 | 805 | if currentbase == base: |
|
829 | 806 | delta = revinfo.cachedelta[1] |
|
830 | 807 | if delta is None: |
|
831 | 808 | delta = self._builddeltadiff(base, revinfo, fh) |
|
832 | 809 | revlog = self.revlog |
|
833 | 810 | header, data = revlog.compress(delta) |
|
834 | 811 | deltalen = len(header) + len(data) |
|
835 | 812 | chainbase = revlog.chainbase(base) |
|
836 | 813 | offset = revlog.end(len(revlog) - 1) |
|
837 | 814 | dist = deltalen + offset - revlog.start(chainbase) |
|
838 | 815 | if revlog._generaldelta: |
|
839 | 816 | deltabase = base |
|
840 | 817 | else: |
|
841 | 818 | deltabase = chainbase |
|
842 | 819 | chainlen, compresseddeltalen = revlog._chaininfo(base) |
|
843 | 820 | chainlen += 1 |
|
844 | 821 | compresseddeltalen += deltalen |
|
845 | 822 | |
|
846 | 823 | revlog = self.revlog |
|
847 | 824 | snapshotdepth = None |
|
848 | 825 | if deltabase == nullrev: |
|
849 | 826 | snapshotdepth = 0 |
|
850 | 827 | elif revlog._sparserevlog and revlog.issnapshot(deltabase): |
|
851 | 828 | # A delta chain should always be one full snapshot, |
|
852 | 829 | # zero or more semi-snapshots, and zero or more deltas |
|
853 | 830 | p1, p2 = revlog.rev(revinfo.p1), revlog.rev(revinfo.p2) |
|
854 | 831 | if deltabase not in (p1, p2) and revlog.issnapshot(deltabase): |
|
855 | 832 | snapshotdepth = len(revlog._deltachain(deltabase)[0]) |
|
856 | 833 | |
|
857 | 834 | return _deltainfo(dist, deltalen, (header, data), deltabase, |
|
858 | 835 | chainbase, chainlen, compresseddeltalen, |
|
859 | 836 | snapshotdepth) |
|
860 | 837 | |
|
861 | 838 | def _fullsnapshotinfo(self, fh, revinfo): |
|
862 | 839 | curr = len(self.revlog) |
|
863 | 840 | rawtext = self.buildtext(revinfo, fh) |
|
864 | 841 | data = self.revlog.compress(rawtext) |
|
865 | 842 | compresseddeltalen = deltalen = dist = len(data[1]) + len(data[0]) |
|
866 | 843 | deltabase = chainbase = curr |
|
867 | 844 | snapshotdepth = 0 |
|
868 | 845 | chainlen = 1 |
|
869 | 846 | |
|
870 | 847 | return _deltainfo(dist, deltalen, data, deltabase, |
|
871 | 848 | chainbase, chainlen, compresseddeltalen, |
|
872 | 849 | snapshotdepth) |
|
873 | 850 | |
|
874 | 851 | def finddeltainfo(self, revinfo, fh): |
|
875 | 852 | """Find an acceptable delta against a candidate revision |
|
876 | 853 | |
|
877 | 854 | revinfo: information about the revision (instance of _revisioninfo) |
|
878 | 855 | fh: file handle to either the .i or the .d revlog file, |
|
879 | 856 | depending on whether it is inlined or not |
|
880 | 857 | |
|
881 | 858 | Returns the first acceptable candidate revision, as ordered by |
|
882 | 859 | _candidategroups |
|
883 | 860 | |
|
884 | 861 | If no suitable deltabase is found, we return delta info for a full |
|
885 | 862 | snapshot. |
|
886 | 863 | """ |
|
887 | 864 | if not revinfo.textlen: |
|
888 | 865 | return self._fullsnapshotinfo(fh, revinfo) |
|
889 | 866 | |
|
890 | 867 | # no delta for flag processor revision (see "candelta" for why) |
|
891 | 868 | # not calling candelta since only one revision needs test, also to |
|
892 | 869 | # avoid overhead fetching flags again. |
|
893 | 870 | if revinfo.flags & REVIDX_RAWTEXT_CHANGING_FLAGS: |
|
894 | 871 | return self._fullsnapshotinfo(fh, revinfo) |
|
895 | 872 | |
|
896 | 873 | cachedelta = revinfo.cachedelta |
|
897 | 874 | p1 = revinfo.p1 |
|
898 | 875 | p2 = revinfo.p2 |
|
899 | 876 | revlog = self.revlog |
|
900 | 877 | |
|
901 | 878 | deltainfo = None |
|
902 | 879 | p1r, p2r = revlog.rev(p1), revlog.rev(p2) |
|
903 | 880 | groups = _candidategroups(self.revlog, revinfo.textlen, |
|
904 | 881 | p1r, p2r, cachedelta) |
|
905 | 882 | candidaterevs = next(groups) |
|
906 | 883 | while candidaterevs is not None: |
|
907 | 884 | nominateddeltas = [] |
|
908 | 885 | if deltainfo is not None: |
|
909 | 886 | # if we already found a good delta, |
|
910 | 887 | # challenge it against refined candidates |
|
911 | 888 | nominateddeltas.append(deltainfo) |
|
912 | 889 | for candidaterev in candidaterevs: |
|
913 | 890 | candidatedelta = self._builddeltainfo(revinfo, candidaterev, fh) |
|
914 | 891 | if isgooddeltainfo(self.revlog, candidatedelta, revinfo): |
|
915 | 892 | nominateddeltas.append(candidatedelta) |
|
916 | 893 | if nominateddeltas: |
|
917 | 894 | deltainfo = min(nominateddeltas, key=lambda x: x.deltalen) |
|
918 | 895 | if deltainfo is not None: |
|
919 | 896 | candidaterevs = groups.send(deltainfo.base) |
|
920 | 897 | else: |
|
921 | 898 | candidaterevs = next(groups) |
|
922 | 899 | |
|
923 | 900 | if deltainfo is None: |
|
924 | 901 | deltainfo = self._fullsnapshotinfo(fh, revinfo) |
|
925 | 902 | return deltainfo |
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