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1 # changegroup.py - Mercurial changegroup manipulation functions
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2 #
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3 # Copyright 2006 Matt Mackall <mpm@selenic.com>
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4 #
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5 # This software may be used and distributed according to the terms of the
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6 # GNU General Public License version 2, incorporated herein by reference.
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7
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8 from i18n import _
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9 import util
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10 import struct, os, bz2, zlib, tempfile
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11
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12 def getchunk(source):
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13 """get a chunk from a changegroup"""
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14 d = source.read(4)
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15 if not d:
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16 return ""
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17 l = struct.unpack(">l", d)[0]
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18 if l <= 4:
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19 return ""
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20 d = source.read(l - 4)
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21 if len(d) < l - 4:
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22 raise util.Abort(_("premature EOF reading chunk"
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23 " (got %d bytes, expected %d)")
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24 % (len(d), l - 4))
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25 return d
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26
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27 def chunkiter(source):
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28 """iterate through the chunks in source"""
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29 while 1:
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30 c = getchunk(source)
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31 if not c:
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32 break
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33 yield c
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34
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35 def chunkheader(length):
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36 """build a changegroup chunk header"""
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37 return struct.pack(">l", length + 4)
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38
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39 def closechunk():
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40 return struct.pack(">l", 0)
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41
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42 class nocompress(object):
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43 def compress(self, x):
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44 return x
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45 def flush(self):
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46 return ""
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47
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48 bundletypes = {
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49 "": ("", nocompress),
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50 "HG10UN": ("HG10UN", nocompress),
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51 "HG10BZ": ("HG10", lambda: bz2.BZ2Compressor()),
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52 "HG10GZ": ("HG10GZ", lambda: zlib.compressobj()),
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53 }
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54
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55 # hgweb uses this list to communicate it's preferred type
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56 bundlepriority = ['HG10GZ', 'HG10BZ', 'HG10UN']
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57
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58 def writebundle(cg, filename, bundletype):
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59 """Write a bundle file and return its filename.
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60
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61 Existing files will not be overwritten.
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62 If no filename is specified, a temporary file is created.
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63 bz2 compression can be turned off.
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64 The bundle file will be deleted in case of errors.
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65 """
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66
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67 fh = None
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68 cleanup = None
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69 try:
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70 if filename:
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71 fh = open(filename, "wb")
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72 else:
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73 fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
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74 fh = os.fdopen(fd, "wb")
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75 cleanup = filename
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76
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77 header, compressor = bundletypes[bundletype]
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78 fh.write(header)
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79 z = compressor()
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80
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81 # parse the changegroup data, otherwise we will block
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82 # in case of sshrepo because we don't know the end of the stream
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83
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84 # an empty chunkiter is the end of the changegroup
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85 # a changegroup has at least 2 chunkiters (changelog and manifest).
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86 # after that, an empty chunkiter is the end of the changegroup
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87 empty = False
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88 count = 0
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89 while not empty or count <= 2:
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90 empty = True
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91 count += 1
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92 for chunk in chunkiter(cg):
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93 empty = False
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94 fh.write(z.compress(chunkheader(len(chunk))))
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95 pos = 0
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96 while pos < len(chunk):
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97 next = pos + 2**20
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98 fh.write(z.compress(chunk[pos:next]))
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99 pos = next
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100 fh.write(z.compress(closechunk()))
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101 fh.write(z.flush())
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102 cleanup = None
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103 return filename
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104 finally:
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105 if fh is not None:
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106 fh.close()
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107 if cleanup is not None:
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108 os.unlink(cleanup)
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109
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110 def unbundle(header, fh):
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111 if header == 'HG10UN':
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112 return fh
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113 elif not header.startswith('HG'):
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114 # old client with uncompressed bundle
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115 def generator(f):
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116 yield header
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117 for chunk in f:
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118 yield chunk
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119 elif header == 'HG10GZ':
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120 def generator(f):
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121 zd = zlib.decompressobj()
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122 for chunk in f:
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123 yield zd.decompress(chunk)
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124 elif header == 'HG10BZ':
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125 def generator(f):
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126 zd = bz2.BZ2Decompressor()
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127 zd.decompress("BZ")
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128 for chunk in util.filechunkiter(f, 4096):
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129 yield zd.decompress(chunk)
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130 return util.chunkbuffer(generator(fh))
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131
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132 def readbundle(fh, fname):
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133 header = fh.read(6)
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134 if not header.startswith('HG'):
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135 raise util.Abort(_('%s: not a Mercurial bundle file') % fname)
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136 if not header.startswith('HG10'):
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137 raise util.Abort(_('%s: unknown bundle version') % fname)
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138 elif header not in bundletypes:
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139 raise util.Abort(_('%s: unknown bundle compression type') % fname)
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140 return unbundle(header, fh)
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