Merge webkit.org at r58033 : Initial merge by git

Change-Id: If006c38561af287c50cd578d251629b51e4d8cd1

1 files changed, 133 insertions, 0 deletions

diff --git a/WebKitTools/Scripts/webkitpy/python24/versioning.py b/WebKitTools/Scripts/webkitpy/python24/versioning.py
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+# Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1.  Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+# 2.  Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Supports Python version checking."""
+
+import logging
+import sys
+
+_log = logging.getLogger("webkitpy.python24.versioning")
+
+# The minimum Python version the webkitpy package supports.
+_MINIMUM_SUPPORTED_PYTHON_VERSION = "2.5"
+
+
+def compare_version(sysmodule=None, target_version=None):
+    """Compare the current Python version with a target version.
+
+    Args:
+      sysmodule: An object with version and version_info data attributes
+                 used to detect the current Python version.  The attributes
+                 should have the same semantics as sys.version and
+                 sys.version_info.  This parameter should only be used
+                 for unit testing.  Defaults to sys.
+      target_version: A string representing the Python version to compare
+                      the current version against.  The string should have
+                      one of the following three forms: 2, 2.5, or 2.5.3.
+                      Defaults to the minimum version that the webkitpy
+                      package supports.
+
+    Returns:
+      A triple of (comparison, current_version, target_version).
+
+      comparison: An integer representing the result of comparing the
+                  current version with the target version.  A positive
+                  number means the current version is greater than the
+                  target, 0 means they are the same, and a negative number
+                  means the current version is less than the target.
+                      This method compares version information only up
+                  to the precision of the given target version.  For
+                  example, if the target version is 2.6 and the current
+                  version is 2.5.3, this method uses 2.5 for the purposes
+                  of comparing with the target.
+      current_version: A string representing the current Python version, for
+                       example 2.5.3.
+      target_version: A string representing the version that the current
+                      version was compared against, for example 2.5.
+
+    """
+    if sysmodule is None:
+        sysmodule = sys
+    if target_version is None:
+        target_version = _MINIMUM_SUPPORTED_PYTHON_VERSION
+
+    # The number of version parts to compare.
+    precision = len(target_version.split("."))
+
+    # We use sys.version_info rather than sys.version since its first
+    # three elements are guaranteed to be integers.
+    current_version_info_to_compare = sysmodule.version_info[:precision]
+    # Convert integers to strings.
+    current_version_info_to_compare = map(str, current_version_info_to_compare)
+    current_version_to_compare = ".".join(current_version_info_to_compare)
+
+    # Compare version strings lexicographically.
+    if current_version_to_compare > target_version:
+        comparison = 1
+    elif current_version_to_compare == target_version:
+        comparison = 0
+    else:
+        comparison = -1
+
+    # The version number portion of the current version string, for
+    # example "2.6.4".
+    current_version = sysmodule.version.split()[0]
+
+    return (comparison, current_version, target_version)
+
+
+# FIXME: Add a logging level parameter to allow the version message
+#        to be logged at levels other than WARNING, for example CRITICAL.
+def check_version(log=None, sysmodule=None, target_version=None):
+    """Check the current Python version against a target version.
+
+    Logs a warning message if the current version is less than the
+    target version.
+
+    Args:
+      log: A logging.logger instance to use when logging the version warning.
+           Defaults to the logger of this module.
+      sysmodule: See the compare_version() docstring.
+      target_version: See the compare_version() docstring.
+
+    Returns:
+      A boolean value of whether the current version is greater than
+      or equal to the target version.
+
+    """
+    if log is None:
+        log = _log
+
+    (comparison, current_version, target_version) = \
+        compare_version(sysmodule, target_version)
+
+    if comparison >= 0:
+        # Then the current version is at least the minimum version.
+        return True
+
+    message = ("WebKit Python scripts do not support your current Python "
+               "version (%s).  The minimum supported version is %s.\n"
+               "  See the following page to upgrade your Python version:\n\n"
+               "    http://trac.webkit.org/wiki/PythonGuidelines\n"
+               % (current_version, target_version))
+    log.warn(message)
+    return False