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1 # Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org) |
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2 # |
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3 # Redistribution and use in source and binary forms, with or without |
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4 # modification, are permitted provided that the following conditions |
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5 # are met: |
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6 # 1. Redistributions of source code must retain the above copyright |
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7 # notice, this list of conditions and the following disclaimer. |
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8 # 2. Redistributions in binary form must reproduce the above copyright |
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9 # notice, this list of conditions and the following disclaimer in the |
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10 # documentation and/or other materials provided with the distribution. |
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11 # |
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12 # THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND |
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13 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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14 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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15 # DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR |
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16 # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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17 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
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18 # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
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19 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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20 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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21 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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22 |
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23 """Supports Python version checking.""" |
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24 |
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25 import logging |
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26 import sys |
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27 |
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28 _log = logging.getLogger("webkitpy.python24.versioning") |
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29 |
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30 # The minimum Python version the webkitpy package supports. |
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31 _MINIMUM_SUPPORTED_PYTHON_VERSION = "2.5" |
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32 |
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33 |
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34 def compare_version(sysmodule=None, target_version=None): |
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35 """Compare the current Python version with a target version. |
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36 |
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37 Args: |
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38 sysmodule: An object with version and version_info data attributes |
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39 used to detect the current Python version. The attributes |
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40 should have the same semantics as sys.version and |
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41 sys.version_info. This parameter should only be used |
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42 for unit testing. Defaults to sys. |
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43 target_version: A string representing the Python version to compare |
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44 the current version against. The string should have |
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45 one of the following three forms: 2, 2.5, or 2.5.3. |
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46 Defaults to the minimum version that the webkitpy |
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47 package supports. |
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48 |
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49 Returns: |
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50 A triple of (comparison, current_version, target_version). |
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51 |
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52 comparison: An integer representing the result of comparing the |
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53 current version with the target version. A positive |
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54 number means the current version is greater than the |
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55 target, 0 means they are the same, and a negative number |
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56 means the current version is less than the target. |
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57 This method compares version information only up |
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58 to the precision of the given target version. For |
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59 example, if the target version is 2.6 and the current |
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60 version is 2.5.3, this method uses 2.5 for the purposes |
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61 of comparing with the target. |
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62 current_version: A string representing the current Python version, for |
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63 example 2.5.3. |
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64 target_version: A string representing the version that the current |
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65 version was compared against, for example 2.5. |
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66 |
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67 """ |
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68 if sysmodule is None: |
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69 sysmodule = sys |
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70 if target_version is None: |
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71 target_version = _MINIMUM_SUPPORTED_PYTHON_VERSION |
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72 |
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73 # The number of version parts to compare. |
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74 precision = len(target_version.split(".")) |
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75 |
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76 # We use sys.version_info rather than sys.version since its first |
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77 # three elements are guaranteed to be integers. |
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78 current_version_info_to_compare = sysmodule.version_info[:precision] |
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79 # Convert integers to strings. |
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80 current_version_info_to_compare = map(str, current_version_info_to_compare) |
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81 current_version_to_compare = ".".join(current_version_info_to_compare) |
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82 |
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83 # Compare version strings lexicographically. |
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84 if current_version_to_compare > target_version: |
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85 comparison = 1 |
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86 elif current_version_to_compare == target_version: |
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87 comparison = 0 |
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88 else: |
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89 comparison = -1 |
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90 |
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91 # The version number portion of the current version string, for |
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92 # example "2.6.4". |
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93 current_version = sysmodule.version.split()[0] |
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94 |
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95 return (comparison, current_version, target_version) |
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96 |
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97 |
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98 # FIXME: Add a logging level parameter to allow the version message |
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99 # to be logged at levels other than WARNING, for example CRITICAL. |
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100 def check_version(log=None, sysmodule=None, target_version=None): |
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101 """Check the current Python version against a target version. |
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102 |
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103 Logs a warning message if the current version is less than the |
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104 target version. |
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105 |
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106 Args: |
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107 log: A logging.logger instance to use when logging the version warning. |
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108 Defaults to the logger of this module. |
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109 sysmodule: See the compare_version() docstring. |
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110 target_version: See the compare_version() docstring. |
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111 |
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112 Returns: |
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113 A boolean value of whether the current version is greater than |
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114 or equal to the target version. |
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115 |
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116 """ |
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117 if log is None: |
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118 log = _log |
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119 |
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120 (comparison, current_version, target_version) = \ |
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121 compare_version(sysmodule, target_version) |
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122 |
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123 if comparison >= 0: |
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124 # Then the current version is at least the minimum version. |
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125 return True |
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126 |
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127 message = ("WebKit Python scripts do not support your current Python " |
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128 "version (%s). The minimum supported version is %s.\n" |
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129 " See the following page to upgrade your Python version:\n\n" |
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130 " http://trac.webkit.org/wiki/PythonGuidelines\n" |
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131 % (current_version, target_version)) |
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132 log.warn(message) |
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133 return False |