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##
# The Version class processes string versions into comparable
# values. A version string should normally be a series of numbers
# separated by periods. Each part (digits separated by periods) is
# considered its own number, and these are used for sorting. So for
# instance, 3.10 sorts higher than 3.2 because ten is greater than
# two.
#
# If any part contains letters (currently only a-z are supported) then
# that version is considered prerelease. Versions with a prerelease
# part in the Nth part sort less than versions with N-1
# parts. Prerelease parts are sorted alphabetically using the normal
# Ruby string sorting rules. If a prerelease part contains both
# letters and numbers, it will be broken into multiple parts to
# provide expected sort behavior (1.0.a10 becomes 1.0.a.10, and is
# greater than 1.0.a9).
#
# Prereleases sort between real releases (newest to oldest):
#
# 1. 1.0
# 2. 1.0.b1
# 3. 1.0.a.2
# 4. 0.9
#
# == How Software Changes
#
# Users expect to be able to specify a version constraint that gives them
# some reasonable expectation that new versions of a library will work with
# their software if the version constraint is true, and not work with their
# software if the version constraint is false. In other words, the perfect
# system will accept all compatible versions of the library and reject all
# incompatible versions.
#
# Libraries change in 3 ways (well, more than 3, but stay focused here!).
#
# 1. The change may be an implementation detail only and have no effect on
# the client software.
# 2. The change may add new features, but do so in a way that client software
# written to an earlier version is still compatible.
# 3. The change may change the public interface of the library in such a way
# that old software is no longer compatible.
#
# Some examples are appropriate at this point. Suppose I have a Stack class
# that supports a <tt>push</tt> and a <tt>pop</tt> method.
#
# === Examples of Category 1 changes:
#
# * Switch from an array based implementation to a linked-list based
# implementation.
# * Provide an automatic (and transparent) backing store for large stacks.
#
# === Examples of Category 2 changes might be:
#
# * Add a <tt>depth</tt> method to return the current depth of the stack.
# * Add a <tt>top</tt> method that returns the current top of stack (without
# changing the stack).
# * Change <tt>push</tt> so that it returns the item pushed (previously it
# had no usable return value).
#
# === Examples of Category 3 changes might be:
#
# * Changes <tt>pop</tt> so that it no longer returns a value (you must use
# <tt>top</tt> to get the top of the stack).
# * Rename the methods to <tt>push_item</tt> and <tt>pop_item</tt>.
#
# == RubyGems Rational Versioning
#
# * Versions shall be represented by three non-negative integers, separated
# by periods (e.g. 3.1.4). The first integers is the "major" version
# number, the second integer is the "minor" version number, and the third
# integer is the "build" number.
#
# * A category 1 change (implementation detail) will increment the build
# number.
#
# * A category 2 change (backwards compatible) will increment the minor
# version number and reset the build number.
#
# * A category 3 change (incompatible) will increment the major build number
# and reset the minor and build numbers.
#
# * Any "public" release of a gem should have a different version. Normally
# that means incrementing the build number. This means a developer can
# generate builds all day long for himself, but as soon as he/she makes a
# public release, the version must be updated.
#
# === Examples
#
# Let's work through a project lifecycle using our Stack example from above.
#
# Version 0.0.1:: The initial Stack class is release.
# Version 0.0.2:: Switched to a linked=list implementation because it is
# cooler.
# Version 0.1.0:: Added a <tt>depth</tt> method.
# Version 1.0.0:: Added <tt>top</tt> and made <tt>pop</tt> return nil
# (<tt>pop</tt> used to return the old top item).
# Version 1.1.0:: <tt>push</tt> now returns the value pushed (it used it
# return nil).
# Version 1.1.1:: Fixed a bug in the linked list implementation.
# Version 1.1.2:: Fixed a bug introduced in the last fix.
#
# Client A needs a stack with basic push/pop capability. He writes to the
# original interface (no <tt>top</tt>), so his version constraint looks
# like:
#
# gem 'stack', '~> 0.0'
#
# Essentially, any version is OK with Client A. An incompatible change to
# the library will cause him grief, but he is willing to take the chance (we
# call Client A optimistic).
#
# Client B is just like Client A except for two things: (1) He uses the
# <tt>depth</tt> method and (2) he is worried about future
# incompatibilities, so he writes his version constraint like this:
#
# gem 'stack', '~> 0.1'
#
# The <tt>depth</tt> method was introduced in version 0.1.0, so that version
# or anything later is fine, as long as the version stays below version 1.0
# where incompatibilities are introduced. We call Client B pessimistic
# because he is worried about incompatible future changes (it is OK to be
# pessimistic!).
#
# == Preventing Version Catastrophe:
#
# From: http://blog.zenspider.com/2008/10/rubygems-howto-preventing-cata.html
#
# Let's say you're depending on the fnord gem version 2.y.z. If you
# specify your dependency as ">= 2.0.0" then, you're good, right? What
# happens if fnord 3.0 comes out and it isn't backwards compatible
# with 2.y.z? Your stuff will break as a result of using ">=". The
# better route is to specify your dependency with an "approximate" version
# specifier ("~>"). They're a tad confusing, so here is how the dependency
# specifiers work:
#
# Specification From ... To (exclusive)
# ">= 3.0" 3.0 ... &infin;
# "~> 3.0" 3.0 ... 4.0
# "~> 3.0.0" 3.0.0 ... 3.1
# "~> 3.5" 3.5 ... 4.0
# "~> 3.5.0" 3.5.0 ... 3.6
class Gem::Version
autoload :Requirement, 'rubygems/requirement'
include Comparable
# FIX: These are only used once, in .correct?. Do they deserve to be
# constants?
VERSION_PATTERN = '[0-9]+(\.[0-9a-zA-Z]+)*' # :nodoc:
ANCHORED_VERSION_PATTERN = /\A\s*(#{VERSION_PATTERN})*\s*\z/ # :nodoc:
##
# A string representation of this Version.
attr_reader :version
alias to_s version
##
# True if the +version+ string matches RubyGems' requirements.
def self.correct? version
version.to_s =~ ANCHORED_VERSION_PATTERN
end
##
# Factory method to create a Version object. Input may be a Version
# or a String. Intended to simplify client code.
#
# ver1 = Version.create('1.3.17') # -> (Version object)
# ver2 = Version.create(ver1) # -> (ver1)
# ver3 = Version.create(nil) # -> nil
# REFACTOR: There's no real reason this should be separate from #initialize.
def self.create input
if input.respond_to? :version then
input
elsif input.nil? then
nil
else
new input
end
end
##
# Constructs a Version from the +version+ string. A version string is a
# series of digits or ASCII letters separated by dots.
def initialize version
raise ArgumentError, "Malformed version number string #{version}" unless
self.class.correct?(version)
@version = version.to_s.strip
end
##
# Return a new version object where the next to the last revision
# number is one greater (e.g., 5.3.1 => 5.4).
#
# Pre-release (alpha) parts, e.g, 5.3.1.b.2 => 5.4, are ignored.
def bump
segments = self.segments.dup
segments.pop while segments.any? { |s| String === s }
segments.pop if segments.size > 1
segments[-1] = segments[-1].succ
self.class.new segments.join(".")
end
##
# A Version is only eql? to another version if it's specified to the
# same precision. Version "1.0" is not the same as version "1".
def eql? other
self.class === other and @version == other.version
end
def hash # :nodoc:
@hash ||= segments.hash
end
def init_with coder # :nodoc:
yaml_initialize coder.tag, coder.map
end
def inspect # :nodoc:
"#<#{self.class} #{version.inspect}>"
end
##
# Dump only the raw version string, not the complete object. It's a
# string for backwards (RubyGems 1.3.5 and earlier) compatibility.
def marshal_dump
[version]
end
##
# Load custom marshal format. It's a string for backwards (RubyGems
# 1.3.5 and earlier) compatibility.
def marshal_load array
initialize array[0]
end
def yaml_initialize(tag, map)
@version = map['version']
@segments = nil
@hash = nil
end
def to_yaml_properties
["@version"]
end
def encode_with coder
coder.add 'version', @version
end
##
# A version is considered a prerelease if it contains a letter.
def prerelease?
@prerelease ||= !!(@version =~ /[a-zA-Z]/)
end
def pretty_print q # :nodoc:
q.text "Gem::Version.new(#{version.inspect})"
end
##
# The release for this version (e.g. 1.2.0.a -> 1.2.0).
# Non-prerelease versions return themselves.
def release
return self unless prerelease?
segments = self.segments.dup
segments.pop while segments.any? { |s| String === s }
self.class.new segments.join('.')
end
def segments # :nodoc:
# segments is lazy so it can pick up version values that come from
# old marshaled versions, which don't go through marshal_load.
@segments ||= @version.scan(/[0-9]+|[a-z]+/i).map do |s|
/^\d+$/ =~ s ? s.to_i : s
end
end
##
# A recommended version for use with a ~> Requirement.
def approximate_recommendation
segments = self.segments.dup
segments.pop while segments.any? { |s| String === s }
segments.pop while segments.size > 2
segments.push 0 while segments.size < 2
"~> #{segments.join(".")}"
end
##
# Compares this version with +other+ returning -1, 0, or 1 if the
# other version is larger, the same, or smaller than this
# one. Attempts to compare to something that's not a
# <tt>Gem::Version</tt> return +nil+.
def <=> other
return unless Gem::Version === other
return 0 if @version == other.version
lhsegments = segments
rhsegments = other.segments
lhsize = lhsegments.size
rhsize = rhsegments.size
limit = (lhsize > rhsize ? lhsize : rhsize) - 1
i = 0
while i <= limit
lhs, rhs = lhsegments[i] || 0, rhsegments[i] || 0
i += 1
next if lhs == rhs
return -1 if String === lhs && Numeric === rhs
return 1 if Numeric === lhs && String === rhs
return lhs <=> rhs
end
return 0
end
end
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