1 | # Copyright (C) 2005 Christian Limpach <Christian.Limpach@cl.cam.ac.uk> |
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2 | # Copyright (C) 2005 XenSource Ltd |
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3 | |
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4 | # This file is subject to the terms and conditions of the GNU General |
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5 | # Public License. See the file "COPYING" in the main directory of |
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6 | # this archive for more details. |
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7 | |
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8 | from xen.xend.xenstore.xsutil import xshandle |
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9 | |
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10 | |
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11 | class xstransact: |
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12 | |
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13 | def __init__(self, path = ""): |
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14 | |
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15 | self.in_transaction = False # Set this temporarily -- if this |
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16 | # constructor fails, then we need to |
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17 | # protect __del__. |
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18 | |
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19 | assert path is not None |
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20 | self.path = path.rstrip("/") |
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21 | self.transaction = xshandle().transaction_start() |
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22 | self.in_transaction = True |
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23 | |
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24 | def __del__(self): |
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25 | if self.in_transaction: |
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26 | xshandle().transaction_end(self.transaction, True) |
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27 | |
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28 | def commit(self): |
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29 | if not self.in_transaction: |
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30 | raise RuntimeError |
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31 | self.in_transaction = False |
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32 | rc = xshandle().transaction_end(self.transaction, False) |
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33 | self.transaction = "0" |
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34 | return rc |
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35 | |
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36 | def abort(self): |
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37 | if not self.in_transaction: |
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38 | return True |
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39 | self.in_transaction = False |
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40 | rc = xshandle().transaction_end(self.transaction, True) |
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41 | self.transaction = "0" |
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42 | return rc |
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43 | |
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44 | def _read(self, key): |
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45 | path = self.prependPath(key) |
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46 | try: |
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47 | return xshandle().read(self.transaction, path) |
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48 | except RuntimeError, ex: |
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49 | raise RuntimeError(ex.args[0], |
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50 | '%s, while reading %s' % (ex.args[1], path)) |
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51 | |
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52 | def read(self, *args): |
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53 | """If no arguments are given, return the value at this transaction's |
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54 | path. If one argument is given, treat that argument as a subpath to |
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55 | this transaction's path, and return the value at that path. |
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56 | Otherwise, treat each argument as a subpath to this transaction's |
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57 | path, and return a list composed of the values at each of those |
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58 | instead. |
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59 | """ |
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60 | if len(args) == 0: |
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61 | return xshandle().read(self.transaction, self.path) |
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62 | if len(args) == 1: |
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63 | return self._read(args[0]) |
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64 | ret = [] |
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65 | for key in args: |
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66 | ret.append(self._read(key)) |
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67 | return ret |
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68 | |
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69 | def _write(self, key, data): |
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70 | path = self.prependPath(key) |
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71 | try: |
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72 | xshandle().write(self.transaction, path, data) |
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73 | except RuntimeError, ex: |
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74 | raise RuntimeError(ex.args[0], |
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75 | ('%s, while writing %s : %s' % |
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76 | (ex.args[1], path, str(data)))) |
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77 | |
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78 | def write(self, *args): |
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79 | if len(args) == 0: |
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80 | raise TypeError |
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81 | if isinstance(args[0], dict): |
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82 | for d in args: |
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83 | if not isinstance(d, dict): |
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84 | raise TypeError |
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85 | for key in d.keys(): |
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86 | try: |
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87 | self._write(key, d[key]) |
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88 | except TypeError, msg: |
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89 | raise TypeError('Writing %s: %s: %s' % |
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90 | (key, str(d[key]), msg)) |
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91 | elif isinstance(args[0], list): |
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92 | for l in args: |
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93 | if not len(l) == 2: |
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94 | raise TypeError |
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95 | self._write(l[0], l[1]) |
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96 | elif len(args) % 2 == 0: |
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97 | for i in range(len(args) / 2): |
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98 | self._write(args[i * 2], args[i * 2 + 1]) |
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99 | else: |
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100 | raise TypeError |
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101 | |
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102 | def _remove(self, key): |
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103 | path = self.prependPath(key) |
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104 | return xshandle().rm(self.transaction, path) |
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105 | |
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106 | def remove(self, *args): |
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107 | """If no arguments are given, remove this transaction's path. |
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108 | Otherwise, treat each argument as a subpath to this transaction's |
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109 | path, and remove each of those instead. |
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110 | """ |
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111 | if len(args) == 0: |
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112 | xshandle().rm(self.transaction, self.path) |
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113 | else: |
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114 | for key in args: |
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115 | self._remove(key) |
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116 | |
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117 | def _list(self, key): |
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118 | path = self.prependPath(key) |
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119 | l = xshandle().ls(self.transaction, path) |
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120 | if l: |
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121 | return map(lambda x: key + "/" + x, l) |
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122 | return [] |
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123 | |
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124 | def list(self, *args): |
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125 | """If no arguments are given, list this transaction's path, returning |
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126 | the entries therein, or the empty list if no entries are found. |
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127 | Otherwise, treat each argument as a subpath to this transaction's |
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128 | path, and return the cumulative listing of each of those instead. |
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129 | """ |
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130 | if len(args) == 0: |
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131 | ret = xshandle().ls(self.transaction, self.path) |
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132 | if ret is None: |
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133 | return [] |
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134 | else: |
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135 | return ret |
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136 | else: |
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137 | ret = [] |
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138 | for key in args: |
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139 | ret.extend(self._list(key)) |
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140 | return ret |
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141 | |
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142 | |
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143 | def list_recursive_(self, subdir, keys): |
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144 | ret = [] |
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145 | for key in keys: |
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146 | new_subdir = subdir + "/" + key |
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147 | l = xshandle().ls(self.transaction, new_subdir) |
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148 | if l: |
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149 | ret.append([key, self.list_recursive_(new_subdir, l)]) |
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150 | else: |
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151 | ret.append([key, xshandle().read(self.transaction, new_subdir)]) |
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152 | return ret |
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153 | |
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154 | |
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155 | def list_recursive(self, *args): |
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156 | """If no arguments are given, list this transaction's path, returning |
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157 | the entries therein, or the empty list if no entries are found. |
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158 | Otherwise, treat each argument as a subpath to this transaction's |
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159 | path, and return the cumulative listing of each of those instead. |
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160 | """ |
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161 | if len(args) == 0: |
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162 | args = self.list() |
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163 | if args is None or len(args) == 0: |
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164 | return [] |
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165 | |
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166 | return self.list_recursive_(self.path, args) |
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167 | |
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168 | |
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169 | def gather(self, *args): |
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170 | if len(args) and type(args[0]) != tuple: |
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171 | args = args, |
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172 | ret = [] |
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173 | for tup in args: |
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174 | if len(tup) == 2: |
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175 | (key, fn) = tup |
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176 | defval = None |
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177 | else: |
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178 | (key, fn, defval) = tup |
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179 | |
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180 | val = self._read(key) |
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181 | # If fn is str, then this will successfully convert None to 'None' |
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182 | # (which we don't want). If it is int or float, then it will |
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183 | # throw ValueError on any non-convertible value. We check |
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184 | # explicitly for None, using defval instead, but allow ValueError |
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185 | # to propagate. |
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186 | if val is None: |
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187 | val = defval |
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188 | else: |
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189 | val = fn(val) |
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190 | ret.append(val) |
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191 | if len(ret) == 1: |
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192 | return ret[0] |
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193 | return ret |
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194 | |
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195 | def store(self, *args): |
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196 | if len(args) and type(args[0]) != tuple: |
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197 | args = args, |
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198 | for tup in args: |
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199 | if len(tup) == 2: |
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200 | (key, val) = tup |
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201 | try: |
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202 | fmt = { str : "%s", |
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203 | int : "%i", |
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204 | float : "%f", |
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205 | long : "%li", |
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206 | type(None) : None }[type(val)] |
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207 | except KeyError: |
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208 | raise TypeError |
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209 | else: |
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210 | (key, val, fmt) = tup |
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211 | if val is None: |
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212 | self._remove(key) |
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213 | else: |
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214 | self._write(key, fmt % val) |
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215 | |
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216 | |
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217 | def mkdir(self, *args): |
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218 | if len(args) == 0: |
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219 | xshandle().mkdir(self.transaction, self.path) |
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220 | else: |
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221 | for key in args: |
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222 | xshandle().mkdir(self.transaction, self.prependPath(key)) |
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223 | |
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224 | |
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225 | def get_permissions(self, *args): |
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226 | """If no arguments are given, return the permissions at this |
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227 | transaction's path. If one argument is given, treat that argument as |
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228 | a subpath to this transaction's path, and return the permissions at |
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229 | that path. Otherwise, treat each argument as a subpath to this |
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230 | transaction's path, and return a list composed of the permissions at |
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231 | each of those instead. |
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232 | """ |
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233 | if len(args) == 0: |
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234 | return xshandle().get_permissions(self.transaction, self.path) |
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235 | if len(args) == 1: |
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236 | return self._get_permissions(args[0]) |
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237 | ret = [] |
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238 | for key in args: |
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239 | ret.append(self._get_permissions(key)) |
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240 | return ret |
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241 | |
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242 | |
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243 | def _get_permissions(self, key): |
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244 | path = self.prependPath(key) |
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245 | try: |
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246 | return xshandle().get_permissions(self.transaction, path) |
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247 | except RuntimeError, ex: |
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248 | raise RuntimeError(ex.args[0], |
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249 | '%s, while getting permissions from %s' % |
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250 | (ex.args[1], path)) |
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251 | |
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252 | |
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253 | def set_permissions(self, *args): |
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254 | if len(args) == 0: |
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255 | raise TypeError |
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256 | elif isinstance(args[0], str): |
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257 | self.callRebased(args[0], self.set_permissions, *args[1:]) |
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258 | else: |
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259 | if not self.path: |
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260 | raise RuntimeError('Cannot set permissions on the root') |
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261 | |
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262 | xshandle().set_permissions(self.transaction, self.path, |
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263 | list(args)) |
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264 | |
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265 | |
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266 | def remove2(self, middlePath, *args): |
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267 | self.callRebased(middlePath, self.remove, *args) |
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268 | |
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269 | |
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270 | def write2(self, middlePath, *args): |
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271 | self.callRebased(middlePath, self.write, *args) |
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272 | |
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273 | |
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274 | def callRebased(self, middlePath, func, *args): |
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275 | oldpath = self.path |
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276 | self.path = self.prependPath(middlePath) |
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277 | try: |
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278 | func(*args) |
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279 | finally: |
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280 | self.path = oldpath |
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281 | |
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282 | |
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283 | def prependPath(self, key): |
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284 | if self.path: |
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285 | return self.path + '/' + key |
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286 | else: |
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287 | return key |
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288 | |
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289 | |
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290 | def Read(cls, path, *args): |
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291 | """If only one argument is given (path), return the value stored at |
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292 | that path. If two arguments are given, treat the second argument as a |
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293 | subpath within the first, and return the value at the composed path. |
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294 | Otherwise, treat each argument after the first as a subpath to the |
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295 | given path, and return a list composed of the values at each of those |
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296 | instead. This operation is performed inside a transaction. |
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297 | """ |
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298 | return complete(path, lambda t: t.read(*args)) |
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299 | Read = classmethod(Read) |
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300 | |
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301 | def Write(cls, path, *args): |
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302 | complete(path, lambda t: t.write(*args)) |
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303 | Write = classmethod(Write) |
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304 | |
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305 | def Remove(cls, path, *args): |
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306 | """If only one argument is given (path), remove it. Otherwise, treat |
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307 | each further argument as a subpath to the given path, and remove each |
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308 | of those instead. This operation is performed inside a transaction. |
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309 | """ |
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310 | complete(path, lambda t: t.remove(*args)) |
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311 | Remove = classmethod(Remove) |
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312 | |
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313 | def List(cls, path, *args): |
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314 | """If only one argument is given (path), list its contents, returning |
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315 | the entries therein, or the empty list if no entries are found. |
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316 | Otherwise, treat each further argument as a subpath to the given path, |
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317 | and return the cumulative listing of each of those instead. This |
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318 | operation is performed inside a transaction. |
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319 | """ |
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320 | return complete(path, lambda t: t.list(*args)) |
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321 | List = classmethod(List) |
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322 | |
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323 | def ListRecursive(cls, path, *args): |
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324 | """If only one argument is given (path), list its contents |
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325 | recursively, returning the entries therein, or the empty list if no |
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326 | entries are found. Otherwise, treat each further argument as a |
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327 | subpath to the given path, and return the cumulative listing of each |
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328 | of those instead. This operation is performed inside a transaction. |
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329 | """ |
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330 | return complete(path, lambda t: t.list_recursive(*args)) |
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331 | ListRecursive = classmethod(ListRecursive) |
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332 | |
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333 | def Gather(cls, path, *args): |
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334 | return complete(path, lambda t: t.gather(*args)) |
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335 | Gather = classmethod(Gather) |
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336 | |
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337 | def Store(cls, path, *args): |
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338 | complete(path, lambda t: t.store(*args)) |
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339 | Store = classmethod(Store) |
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340 | |
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341 | def SetPermissions(cls, path, *args): |
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342 | complete(path, lambda t: t.set_permissions(*args)) |
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343 | SetPermissions = classmethod(SetPermissions) |
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344 | |
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345 | def Mkdir(cls, path, *args): |
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346 | complete(path, lambda t: t.mkdir(*args)) |
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347 | Mkdir = classmethod(Mkdir) |
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348 | |
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349 | |
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350 | def complete(path, f): |
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351 | while True: |
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352 | t = xstransact(path) |
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353 | try: |
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354 | result = f(t) |
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355 | if t.commit(): |
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356 | return result |
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357 | except: |
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358 | t.abort() |
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359 | raise |
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