1 files changed, 116 insertions, 0 deletions
diff --git a/lib/chef/version_constraint.rb b/lib/chef/version_constraint.rb
new file mode 100644
index 0000000000..b6f1f08757
--- /dev/null
+++ b/lib/chef/version_constraint.rb
@@ -0,0 +1,116 @@
+# Author:: Seth Falcon (<seth@opscode.com>)
+# Author:: Christopher Walters (<cw@opscode.com>)
+# Copyright:: Copyright 2010-2011 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+require 'chef/version_class'
+
+class Chef
+  class VersionConstraint
+    DEFAULT_CONSTRAINT = ">= 0.0.0"
+    STANDARD_OPS = %w(< > <= >=)
+    OPS = %w(< > = <= >= ~>)
+    PATTERN = /^(#{OPS.join('|')}) (.+)$/
+
+    attr_reader :op, :version
+
+    def initialize(constraint_spec=DEFAULT_CONSTRAINT)
+      case constraint_spec
+      when nil
+        parse(DEFAULT_CONSTRAINT)
+      when Array
+        parse_from_array(constraint_spec)
+      when String
+        parse(constraint_spec)
+      else
+        msg = "VersionConstraint should be created from a String. You gave: #{constraint_spec.inspect}"
+        raise Chef::Exceptions::InvalidVersionConstraint, msg
+      end
+    end
+
+    def include?(v)
+      version = if v.respond_to? :version # a CookbookVersion-like object
+                  Chef::Version.new(v.version.to_s)
+                else
+                  Chef::Version.new(v.to_s)
+                end
+     do_op(version)
+    end
+
+    def inspect
+      "(#{@op} #{@version})"
+    end
+
+    def to_s
+      "#{@op} #{@version}"
+    end
+
+    def eql?(o)
+      o.class == self.class && @op == o.op && @version == o.version
+    end
+    alias_method :==, :eql?
+
+    private
+
+    def do_op(other_version)
+      if STANDARD_OPS.include? @op
+        other_version.send(@op.to_sym, @version)
+      elsif @op == '='
+        other_version == @version
+      elsif @op == '~>'
+        if @missing_patch_level
+          (other_version.major == @version.major &&
+           other_version.minor >= @version.minor)
+        else
+          (other_version.major == @version.major &&
+           other_version.minor == @version.minor &&
+           other_version.patch >= @version.patch)
+        end
+      else                      # should never happen
+        raise "bad op #{@op}"
+      end
+    end
+
+    def parse_from_array(constraint_spec)
+      if constraint_spec.empty?
+        parse(DEFAULT_CONSTRAINT)
+      elsif constraint_spec.size == 1
+        parse(constraint_spec.first)
+      else
+        msg = "only one version constraint operation is supported, but you gave #{constraint_spec.size} "
+        msg << "['#{constraint_spec.join(', ')}']"
+        raise Chef::Exceptions::InvalidVersionConstraint, msg
+      end
+    end
+
+    def parse(str)
+      @missing_patch_level = false
+      if str.index(" ").nil? && str =~ /^[0-9]/
+        # try for lone version, implied '='
+        @version = Chef::Version.new(str)
+        @op = "="
+      elsif PATTERN.match str
+        @op = $1
+        raw_version = $2
+        @version = Chef::Version.new(raw_version)
+        if raw_version.split('.').size == 2
+          @missing_patch_level = true
+        end
+      else
+        raise Chef::Exceptions::InvalidVersionConstraint, "'#{str}'"
+      end
+    end
+
+  end
+end