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1 | 1 | # obsolete.py - obsolete markers handling |
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2 | 2 | # |
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3 | 3 | # Copyright 2012 Pierre-Yves David <pierre-yves.david@ens-lyon.org> |
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4 | 4 | # Logilab SA <contact@logilab.fr> |
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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 | |
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9 | 9 | """Obsolete markers handling |
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10 | 10 | |
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11 | 11 | An obsolete marker maps an old changeset to a list of new |
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12 | 12 | changesets. If the list of new changesets is empty, the old changeset |
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13 | 13 | is said to be "killed". Otherwise, the old changeset is being |
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14 | 14 | "replaced" by the new changesets. |
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15 | 15 | |
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16 | 16 | Obsolete markers can be used to record and distribute changeset graph |
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17 | 17 | transformations performed by history rewriting operations, and help |
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18 | 18 | building new tools to reconciliate conflicting rewriting actions. To |
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19 | 19 | facilitate conflicts resolution, markers include various annotations |
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20 | 20 | besides old and news changeset identifiers, such as creation date or |
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21 | 21 | author name. |
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22 | 22 | |
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23 | 23 | |
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24 | 24 | Format |
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25 | 25 | ------ |
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26 | 26 | |
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27 | 27 | Markers are stored in an append-only file stored in |
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28 | 28 | '.hg/store/obsstore'. |
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29 | 29 | |
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30 | 30 | The file starts with a version header: |
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31 | 31 | |
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32 | 32 | - 1 unsigned byte: version number, starting at zero. |
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33 | 33 | |
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34 | 34 | |
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35 | 35 | The header is followed by the markers. Each marker is made of: |
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36 | 36 | |
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37 | 37 | - 1 unsigned byte: number of new changesets "R", could be zero. |
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38 | 38 | |
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39 | 39 | - 1 unsigned 32-bits integer: metadata size "M" in bytes. |
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40 | 40 | |
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41 | 41 | - 1 byte: a bit field. It is reserved for flags used in obsolete |
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42 | 42 | markers common operations, to avoid repeated decoding of metadata |
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43 | 43 | entries. |
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44 | 44 | |
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45 | 45 | - 20 bytes: obsoleted changeset identifier. |
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46 | 46 | |
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47 | 47 | - N*20 bytes: new changesets identifiers. |
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48 | 48 | |
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49 | 49 | - M bytes: metadata as a sequence of nul-terminated strings. Each |
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50 | 50 | string contains a key and a value, separated by a color ':', without |
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51 | 51 | additional encoding. Keys cannot contain '\0' or ':' and values |
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52 | 52 | cannot contain '\0'. |
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53 | 53 | """ |
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54 | 54 | import struct |
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55 | 55 | from mercurial import util, base85 |
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56 | 56 | from i18n import _ |
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57 | 57 | |
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58 | 58 | _pack = struct.pack |
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59 | 59 | _unpack = struct.unpack |
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60 | 60 | |
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61 | 61 | |
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62 | 62 | |
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63 | 63 | # data used for parsing and writing |
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64 | 64 | _fmversion = 0 |
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65 | 65 | _fmfixed = '>BIB20s' |
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66 | 66 | _fmnode = '20s' |
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67 | 67 | _fmfsize = struct.calcsize(_fmfixed) |
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68 | 68 | _fnodesize = struct.calcsize(_fmnode) |
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69 | 69 | |
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70 | 70 | def _readmarkers(data): |
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71 | 71 | """Read and enumerate markers from raw data""" |
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72 | 72 | off = 0 |
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73 | 73 | diskversion = _unpack('>B', data[off:off + 1])[0] |
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74 | 74 | off += 1 |
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75 | 75 | if diskversion != _fmversion: |
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76 | 76 | raise util.Abort(_('parsing obsolete marker: unknown version %r') |
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77 | 77 | % diskversion) |
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78 | 78 | |
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79 | 79 | # Loop on markers |
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80 | 80 | l = len(data) |
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81 | 81 | while off + _fmfsize <= l: |
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82 | 82 | # read fixed part |
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83 | 83 | cur = data[off:off + _fmfsize] |
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84 | 84 | off += _fmfsize |
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85 | 85 | nbsuc, mdsize, flags, pre = _unpack(_fmfixed, cur) |
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86 | 86 | # read replacement |
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87 | 87 | sucs = () |
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88 | 88 | if nbsuc: |
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89 | 89 | s = (_fnodesize * nbsuc) |
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90 | 90 | cur = data[off:off + s] |
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91 | 91 | sucs = _unpack(_fmnode * nbsuc, cur) |
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92 | 92 | off += s |
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93 | 93 | # read metadata |
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94 | 94 | # (metadata will be decoded on demand) |
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95 | 95 | metadata = data[off:off + mdsize] |
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96 | 96 | if len(metadata) != mdsize: |
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97 | 97 | raise util.Abort(_('parsing obsolete marker: metadata is too ' |
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98 | 98 | 'short, %d bytes expected, got %d') |
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99 | 99 | % (len(metadata), mdsize)) |
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100 | 100 | off += mdsize |
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101 | 101 | yield (pre, sucs, flags, metadata) |
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102 | 102 | |
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103 | 103 | def encodemeta(meta): |
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104 | 104 | """Return encoded metadata string to string mapping. |
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105 | 105 | |
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106 | 106 | Assume no ':' in key and no '\0' in both key and value.""" |
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107 | 107 | for key, value in meta.iteritems(): |
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108 | 108 | if ':' in key or '\0' in key: |
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109 | 109 | raise ValueError("':' and '\0' are forbidden in metadata key'") |
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110 | 110 | if '\0' in value: |
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111 | 111 | raise ValueError("':' are forbidden in metadata value'") |
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112 | 112 | return '\0'.join(['%s:%s' % (k, meta[k]) for k in sorted(meta)]) |
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113 | 113 | |
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114 | 114 | def decodemeta(data): |
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115 | 115 | """Return string to string dictionary from encoded version.""" |
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116 | 116 | d = {} |
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117 | 117 | for l in data.split('\0'): |
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118 | 118 | if l: |
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119 | 119 | key, value = l.split(':') |
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120 | 120 | d[key] = value |
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121 | 121 | return d |
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122 | 122 | |
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123 | 123 | class marker(object): |
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124 | 124 | """Wrap obsolete marker raw data""" |
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125 | 125 | |
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126 | 126 | def __init__(self, repo, data): |
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127 | 127 | # the repo argument will be used to create changectx in later version |
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128 | 128 | self._repo = repo |
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129 | 129 | self._data = data |
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130 | 130 | self._decodedmeta = None |
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131 | 131 | |
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132 | 132 | def precnode(self): |
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133 | 133 | """Precursor changeset node identifier""" |
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134 | 134 | return self._data[0] |
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135 | 135 | |
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136 | 136 | def succnodes(self): |
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137 | 137 | """List of successor changesets node identifiers""" |
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138 | 138 | return self._data[1] |
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139 | 139 | |
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140 | 140 | def metadata(self): |
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141 | 141 | """Decoded metadata dictionary""" |
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142 | 142 | if self._decodedmeta is None: |
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143 | 143 | self._decodedmeta = decodemeta(self._data[3]) |
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144 | 144 | return self._decodedmeta |
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145 | 145 | |
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146 | 146 | def date(self): |
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147 | 147 | """Creation date as (unixtime, offset)""" |
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148 | 148 | parts = self.metadata()['date'].split(' ') |
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149 | 149 | return (float(parts[0]), int(parts[1])) |
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150 | 150 | |
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151 | 151 | class obsstore(object): |
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152 | 152 | """Store obsolete markers |
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153 | 153 | |
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154 | 154 | Markers can be accessed with two mappings: |
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155 | 155 | - precursors: old -> set(new) |
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156 | 156 | - successors: new -> set(old) |
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157 | 157 | """ |
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158 | 158 | |
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159 | 159 | def __init__(self): |
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160 | 160 | self._all = [] |
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161 | 161 | # new markers to serialize |
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162 | 162 | self._new = [] |
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163 | 163 | self.precursors = {} |
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164 | 164 | self.successors = {} |
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165 | 165 | |
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166 | 166 | def __iter__(self): |
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167 | 167 | return iter(self._all) |
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168 | 168 | |
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169 | 169 | def __nonzero__(self): |
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170 | 170 | return bool(self._all) |
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171 | 171 | |
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172 | 172 | def create(self, prec, succs=(), flag=0, metadata=None): |
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173 | 173 | """obsolete: add a new obsolete marker |
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174 | 174 | |
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175 | 175 | * ensuring it is hashable |
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176 | 176 | * check mandatory metadata |
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177 | 177 | * encode metadata |
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178 | 178 | """ |
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179 | 179 | if metadata is None: |
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180 | 180 | metadata = {} |
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181 | 181 | if len(prec) != 20: |
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182 | 182 | raise ValueError(prec) |
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183 | 183 | for succ in succs: |
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184 | 184 | if len(succ) != 20: |
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185 |
raise ValueError( |
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185 | raise ValueError(succ) | |
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186 | 186 | marker = (str(prec), tuple(succs), int(flag), encodemeta(metadata)) |
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187 | 187 | self.add(marker) |
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188 | 188 | |
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189 | 189 | def add(self, marker): |
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190 | 190 | """Add a new marker to the store |
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191 | 191 | |
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192 | 192 | This marker still needs to be written to disk""" |
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193 | 193 | self._new.append(marker) |
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194 | 194 | self._load(marker) |
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195 | 195 | |
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196 | 196 | def loadmarkers(self, data): |
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197 | 197 | """Load all markers in data, mark them as known.""" |
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198 | 198 | for marker in _readmarkers(data): |
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199 | 199 | self._load(marker) |
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200 | 200 | |
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201 | 201 | def mergemarkers(self, data): |
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202 | 202 | other = set(_readmarkers(data)) |
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203 | 203 | local = set(self._all) |
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204 | 204 | new = other - local |
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205 | 205 | for marker in new: |
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206 | 206 | self.add(marker) |
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207 | 207 | |
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208 | 208 | def flushmarkers(self, stream): |
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209 | 209 | """Write all markers to a stream |
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210 | 210 | |
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211 | 211 | After this operation, "new" markers are considered "known".""" |
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212 | 212 | self._writemarkers(stream) |
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213 | 213 | self._new[:] = [] |
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214 | 214 | |
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215 | 215 | def _load(self, marker): |
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216 | 216 | self._all.append(marker) |
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217 | 217 | pre, sucs = marker[:2] |
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218 | 218 | self.precursors.setdefault(pre, set()).add(marker) |
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219 | 219 | for suc in sucs: |
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220 | 220 | self.successors.setdefault(suc, set()).add(marker) |
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221 | 221 | |
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222 | 222 | def _writemarkers(self, stream=None): |
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223 | 223 | # Kept separate from flushmarkers(), it will be reused for |
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224 | 224 | # markers exchange. |
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225 | 225 | if stream is None: |
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226 | 226 | final = [] |
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227 | 227 | w = final.append |
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228 | 228 | else: |
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229 | 229 | w = stream.write |
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230 | 230 | w(_pack('>B', _fmversion)) |
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231 | 231 | for marker in self._all: |
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232 | 232 | pre, sucs, flags, metadata = marker |
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233 | 233 | nbsuc = len(sucs) |
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234 | 234 | format = _fmfixed + (_fmnode * nbsuc) |
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235 | 235 | data = [nbsuc, len(metadata), flags, pre] |
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236 | 236 | data.extend(sucs) |
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237 | 237 | w(_pack(format, *data)) |
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238 | 238 | w(metadata) |
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239 | 239 | if stream is None: |
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240 | 240 | return ''.join(final) |
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241 | 241 | |
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242 | 242 | def listmarkers(repo): |
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243 | 243 | """List markers over pushkey""" |
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244 | 244 | if not repo.obsstore: |
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245 | 245 | return {} |
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246 | 246 | data = repo.obsstore._writemarkers() |
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247 | 247 | return {'dump': base85.b85encode(data)} |
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248 | 248 | |
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249 | 249 | def pushmarker(repo, key, old, new): |
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250 | 250 | """Push markers over pushkey""" |
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251 | 251 | if key != 'dump': |
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252 | 252 | repo.ui.warn(_('unknown key: %r') % key) |
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253 | 253 | return 0 |
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254 | 254 | if old: |
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255 | 255 | repo.ui.warn(_('unexpected old value') % key) |
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256 | 256 | return 0 |
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257 | 257 | data = base85.b85decode(new) |
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258 | 258 | lock = repo.lock() |
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259 | 259 | try: |
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260 | 260 | repo.obsstore.mergemarkers(data) |
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261 | 261 | return 1 |
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262 | 262 | finally: |
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263 | 263 | lock.release() |
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264 | 264 | |
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265 | 265 | def allmarkers(repo): |
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266 | 266 | """all obsolete markers known in a repository""" |
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267 | 267 | for markerdata in repo.obsstore: |
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268 | 268 | yield marker(repo, markerdata) |
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269 | 269 | |
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270 | 270 | def precursormarkers(ctx): |
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271 | 271 | """obsolete marker making this changeset obsolete""" |
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272 | 272 | for data in ctx._repo.obsstore.precursors.get(ctx.node(), ()): |
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273 | 273 | yield marker(ctx._repo, data) |
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274 | 274 | |
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275 | 275 | def successormarkers(ctx): |
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276 | 276 | """obsolete marker marking this changeset as a successors""" |
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277 | 277 | for data in ctx._repo.obsstore.successors.get(ctx.node(), ()): |
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278 | 278 | yield marker(ctx._repo, data) |
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279 | 279 |
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