Unvendor'd MemCache-Client. Now requires the MemCache Client gem as a dependency - Don't forget to gem bundle buys and girls

6 files changed, 5 insertions, 1157 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 2d80f3ce6b..cd72aa1bee 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,8 +1,10 @@
 *Edge*
 
-* Unvendor'd Builder.  Now requires the Builder gem as a dependency
+* Unvendor'd Memcach Client.  Now requires the Builder gem as a dependency [Mikel Lindsaar]
 
-* Unvendor'd TZInfo.  Now requires the TZInfo gem as a dependency
+* Unvendor'd Builder.  Now requires the Builder gem as a dependency [Mikel Lindsaar]
+
+* Unvendor'd TZInfo.  Now requires the TZInfo gem as a dependency [Mikel Lindsaar]
 
 * YAML serialization for OrderedHash.  #3608 [Gregor Schmidt]
 
diff --git a/activesupport/Rakefile b/activesupport/Rakefile
index 434c5e2ed4..03ab3b2760 100644
--- a/activesupport/Rakefile
+++ b/activesupport/Rakefile
@@ -41,7 +41,6 @@ Rake::RDocTask.new { |rdoc|
   rdoc.rdoc_files.include('README', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/active_support.rb')
   rdoc.rdoc_files.include('lib/active_support/**/*.rb')
-  rdoc.rdoc_files.exclude('lib/active_support/vendor/*')
 }
 
 spec = eval(File.read('activesupport.gemspec'))
diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
index ada5c5c0fe..19cdbaa41a 100644
--- a/activesupport/activesupport.gemspec
+++ b/activesupport/activesupport.gemspec
@@ -9,6 +9,7 @@ Gem::Specification.new do |s|
   s.add_dependency('i18n', '~> 0.3.0')
   s.add_dependency('tzinfo', '~> 0.3.16')
   s.add_dependency('builder', '~> 2.1.2')
+  s.add_dependency('memcache-client', '~> 1.7.5')
 
   s.files = Dir['CHANGELOG', 'README', 'lib/**/*']
   s.require_path = 'lib'
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 51ec87f329..833ae351b9 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -69,5 +69,3 @@ module ActiveSupport
 
   autoload :TestCase
 end
-
-require 'active_support/vendor'
diff --git a/activesupport/lib/active_support/vendor.rb b/activesupport/lib/active_support/vendor.rb
deleted file mode 100644
index caa77d19e2..0000000000
--- a/activesupport/lib/active_support/vendor.rb
+++ /dev/null
@@ -1,19 +0,0 @@
-require 'pathname'
-
-def ActiveSupport.requirable?(file)
-  $LOAD_PATH.any? { |p| Dir.glob("#{p}/#{file}.*").any? }
-end
-
-[%w(builder 2.1.2), %w(memcache-client 1.7.5)].each do |lib, version|
-  # If the lib is not already requirable
-  unless ActiveSupport.requirable? lib
-    # Try to activate a gem ~> satisfying the requested version first.
-    begin
-      gem lib, ">= #{version}"
-      # Use the vendored lib if the gem's missing or we aren't using RubyGems.
-    rescue LoadError, NoMethodError
-      # There could be symlinks
-      $LOAD_PATH.unshift Pathname.new(__FILE__).dirname.join("vendor/#{lib}-#{version}/lib").realpath.to_s
-    end
-  end
-end
diff --git a/activesupport/lib/active_support/vendor/memcache-client-1.7.5/lib/memcache.rb b/activesupport/lib/active_support/vendor/memcache-client-1.7.5/lib/memcache.rb
deleted file mode 100644
index 3fcc388ba0..0000000000
--- a/activesupport/lib/active_support/vendor/memcache-client-1.7.5/lib/memcache.rb
+++ /dev/null
@@ -1,1133 +0,0 @@
-$TESTING = defined?($TESTING) && $TESTING
-
-require 'socket'
-require 'thread'
-require 'zlib'
-require 'digest/sha1'
-require 'net/protocol'
-
-##
-# A Ruby client library for memcached.
-#
-
-class MemCache
-
-  ##
-  # The version of MemCache you are using.
-
-  VERSION = '1.7.5'
-
-  ##
-  # Default options for the cache object.
-
-  DEFAULT_OPTIONS = {
-    :namespace    => nil,
-    :readonly     => false,
-    :multithread  => true,
-    :failover     => true,
-    :timeout      => 0.5,
-    :logger       => nil,
-    :no_reply     => false,
-    :check_size   => true,
-    :autofix_keys => false,
-    :namespace_separator => ':',
-  }
-
-  ##
-  # Default memcached port.
-
-  DEFAULT_PORT = 11211
-
-  ##
-  # Default memcached server weight.
-
-  DEFAULT_WEIGHT = 1
-
-  ##
-  # The namespace for this instance
-
-  attr_reader :namespace
-
-  ##
-  # The multithread setting for this instance
-
-  attr_reader :multithread
-
-  ##
-  # Whether to try to fix keys that are too long and will be truncated by
-  # using their SHA1 hash instead.
-  # The hash is only used on keys longer than 250 characters, or containing spaces,
-  # to avoid impacting performance unnecesarily.
-  #
-  # In theory, your code should generate correct keys when calling memcache, 
-  # so it's your responsibility and you should try to fix this problem at its source.
-  #
-  # But if that's not possible, enable this option and memcache-client will give you a hand.
-  
-  attr_reader :autofix_keys
-  
-  ##
-  # The servers this client talks to.  Play at your own peril.
-
-  attr_reader :servers
-
-  ##
-  # Socket timeout limit with this client, defaults to 0.5 sec.
-  # Set to nil to disable timeouts.
-
-  attr_reader :timeout
-
-  ##
-  # Should the client try to failover to another server if the
-  # first server is down?  Defaults to true.
-
-  attr_reader :failover
-
-  ##
-  # Log debug/info/warn/error to the given Logger, defaults to nil.
-
-  attr_reader :logger
-
-  ##
-  # Don't send or look for a reply from the memcached server for write operations.
-  # Please note this feature only works in memcached 1.2.5 and later.  Earlier
-  # versions will reply with "ERROR".
-  attr_reader :no_reply
-
-  ##
-  # Accepts a list of +servers+ and a list of +opts+.  +servers+ may be
-  # omitted.  See +servers=+ for acceptable server list arguments.
-  #
-  # Valid options for +opts+ are:
-  #
-  #   [:namespace]    Prepends this value to all keys added or retrieved.
-  #   [:readonly]     Raises an exception on cache writes when true.
-  #   [:multithread]  Wraps cache access in a Mutex for thread safety. Defaults to true.
-  #   [:failover]     Should the client try to failover to another server if the
-  #                   first server is down?  Defaults to true.
-  #   [:timeout]      Time to use as the socket read timeout.  Defaults to 0.5 sec,
-  #                   set to nil to disable timeouts.
-  #   [:logger]       Logger to use for info/debug output, defaults to nil
-  #   [:no_reply]     Don't bother looking for a reply for write operations (i.e. they
-  #                   become 'fire and forget'), memcached 1.2.5 and later only, speeds up
-  #                   set/add/delete/incr/decr significantly.
-  #   [:check_size]   Raises a MemCacheError if the value to be set is greater than 1 MB, which
-  #                   is the maximum key size for the standard memcached server.  Defaults to true.
-  #   [:autofix_keys] If a key is longer than 250 characters or contains spaces, 
-  #                   use an SHA1 hash instead, to prevent collisions on truncated keys.
-  # Other options are ignored.
-
-  def initialize(*args)
-    servers = []
-    opts = {}
-
-    case args.length
-    when 0 then # NOP
-    when 1 then
-      arg = args.shift
-      case arg
-      when Hash   then opts = arg
-      when Array  then servers = arg
-      when String then servers = [arg]
-      else raise ArgumentError, 'first argument must be Array, Hash or String'
-      end
-    when 2 then
-      servers, opts = args
-    else
-      raise ArgumentError, "wrong number of arguments (#{args.length} for 2)"
-    end
-
-    opts = DEFAULT_OPTIONS.merge opts
-    @namespace    = opts[:namespace]
-    @readonly     = opts[:readonly]
-    @multithread  = opts[:multithread]
-    @autofix_keys = opts[:autofix_keys]
-    @timeout      = opts[:timeout]
-    @failover     = opts[:failover]
-    @logger       = opts[:logger]
-    @no_reply     = opts[:no_reply]
-    @check_size   = opts[:check_size]
-    @namespace_separator = opts[:namespace_separator]
-    @mutex        = Mutex.new if @multithread
-
-    logger.info { "memcache-client #{VERSION} #{Array(servers).inspect}" } if logger
-
-    Thread.current[:memcache_client] = self.object_id if !@multithread
-
-    self.servers = servers
-  end
-
-  ##
-  # Returns a string representation of the cache object.
-
-  def inspect
-    "<MemCache: %d servers, ns: %p, ro: %p>" %
-      [@servers.length, @namespace, @readonly]
-  end
-
-  ##
-  # Returns whether there is at least one active server for the object.
-
-  def active?
-    not @servers.empty?
-  end
-
-  ##
-  # Returns whether or not the cache object was created read only.
-
-  def readonly?
-    @readonly
-  end
-
-  ##
-  # Set the servers that the requests will be distributed between.  Entries
-  # can be either strings of the form "hostname:port" or
-  # "hostname:port:weight" or MemCache::Server objects.
-  #
-  def servers=(servers)
-    # Create the server objects.
-    @servers = Array(servers).collect do |server|
-      case server
-      when String
-        host, port, weight = server.split ':', 3
-        port ||= DEFAULT_PORT
-        weight ||= DEFAULT_WEIGHT
-        Server.new self, host, port, weight
-      else
-        server
-      end
-    end
-
-    logger.debug { "Servers now: #{@servers.inspect}" } if logger
-
-    # There's no point in doing this if there's only one server
-    @continuum = create_continuum_for(@servers) if @servers.size > 1
-
-    @servers
-  end
-
-  ##
-  # Decrements the value for +key+ by +amount+ and returns the new value.
-  # +key+ must already exist.  If +key+ is not an integer, it is assumed to be
-  # 0.  +key+ can not be decremented below 0.
-
-  def decr(key, amount = 1)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    with_server(key) do |server, cache_key|
-      cache_decr server, cache_key, amount
-    end
-  rescue TypeError => err
-    handle_error nil, err
-  end
-
-  ##
-  # Retrieves +key+ from memcache.  If +raw+ is false, the value will be
-  # unmarshalled.
-
-  def get(key, raw = false)
-    with_server(key) do |server, cache_key|
-      logger.debug { "get #{key} from #{server.inspect}" } if logger
-      value = cache_get server, cache_key
-      return nil if value.nil?
-      value = Marshal.load value unless raw
-      return value
-    end
-  rescue TypeError => err
-    handle_error nil, err
-  end
-
-  ##
-  # Performs a +get+ with the given +key+.  If 
-  # the value does not exist and a block was given,
-  # the block will be called and the result saved via +add+.
-  #
-  # If you do not provide a block, using this
-  # method is the same as using +get+.
-  #
-  def fetch(key, expiry = 0, raw = false)
-    value = get(key, raw)
-
-    if value.nil? && block_given?
-      value = yield
-      add(key, value, expiry, raw)
-    end
-
-    value
-  end
-
-  ##
-  # Retrieves multiple values from memcached in parallel, if possible.
-  #
-  # The memcached protocol supports the ability to retrieve multiple
-  # keys in a single request.  Pass in an array of keys to this method
-  # and it will:
-  #
-  # 1. map the key to the appropriate memcached server
-  # 2. send a single request to each server that has one or more key values
-  #
-  # Returns a hash of values.
-  #
-  #   cache["a"] = 1
-  #   cache["b"] = 2
-  #   cache.get_multi "a", "b" # => { "a" => 1, "b" => 2 }
-  #
-  # Note that get_multi assumes the values are marshalled.
-
-  def get_multi(*keys)
-    raise MemCacheError, 'No active servers' unless active?
-
-    keys.flatten!
-    key_count = keys.length
-    cache_keys = {}
-    server_keys = Hash.new { |h,k| h[k] = [] }
-
-    # map keys to servers
-    keys.each do |key|
-      server, cache_key = request_setup key
-      cache_keys[cache_key] = key
-      server_keys[server] << cache_key
-    end
-
-    results = {}
-
-    server_keys.each do |server, keys_for_server|
-      keys_for_server_str = keys_for_server.join ' '
-      begin
-        values = cache_get_multi server, keys_for_server_str
-        values.each do |key, value|
-          results[cache_keys[key]] = Marshal.load value
-        end
-      rescue IndexError => e
-        # Ignore this server and try the others
-        logger.warn { "Unable to retrieve #{keys_for_server.size} elements from #{server.inspect}: #{e.message}"} if logger
-      end
-    end
-
-    return results
-  rescue TypeError => err
-    handle_error nil, err
-  end
-
-  ##
-  # Increments the value for +key+ by +amount+ and returns the new value.
-  # +key+ must already exist.  If +key+ is not an integer, it is assumed to be
-  # 0.
-
-  def incr(key, amount = 1)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    with_server(key) do |server, cache_key|
-      cache_incr server, cache_key, amount
-    end
-  rescue TypeError => err
-    handle_error nil, err
-  end
-
-  ##
-  # Add +key+ to the cache with value +value+ that expires in +expiry+
-  # seconds.  If +raw+ is true, +value+ will not be Marshalled.
-  #
-  # Warning: Readers should not call this method in the event of a cache miss;
-  # see MemCache#add.
-
-  ONE_MB = 1024 * 1024
-
-  def set(key, value, expiry = 0, raw = false)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-
-    value = Marshal.dump value unless raw
-    with_server(key) do |server, cache_key|
-      logger.debug { "set #{key} to #{server.inspect}: #{value.to_s.size}" } if logger
-
-      if @check_size && value.to_s.size > ONE_MB
-        raise MemCacheError, "Value too large, memcached can only store 1MB of data per key"
-      end
-
-      command = "set #{cache_key} 0 #{expiry} #{value.to_s.size}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-
-        if result.nil?
-          server.close
-          raise MemCacheError, "lost connection to #{server.host}:#{server.port}"
-        end
-
-        result
-      end
-    end
-  end
-
-  ##
-  # "cas" is a check and set operation which means "store this data but
-  # only if no one else has updated since I last fetched it."  This can
-  # be used as a form of optimistic locking.
-  #
-  # Works in block form like so:
-  #   cache.cas('some-key') do |value|
-  #     value + 1
-  #   end
-  #
-  # Returns:
-  # +nil+ if the value was not found on the memcached server.
-  # +STORED+ if the value was updated successfully
-  # +EXISTS+ if the value was updated by someone else since last fetch
-
-  def cas(key, expiry=0, raw=false)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    raise MemCacheError, "A block is required" unless block_given?
-
-    (value, token) = gets(key, raw)
-    return nil unless value
-    updated = yield value
-    value = Marshal.dump updated unless raw
-
-    with_server(key) do |server, cache_key|
-      logger.debug { "cas #{key} to #{server.inspect}: #{value.to_s.size}" } if logger
-      command = "cas #{cache_key} 0 #{expiry} #{value.to_s.size} #{token}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-
-        if result.nil?
-          server.close
-          raise MemCacheError, "lost connection to #{server.host}:#{server.port}"
-        end
-
-        result
-      end
-    end
-  end
-
-  ##
-  # Add +key+ to the cache with value +value+ that expires in +expiry+
-  # seconds, but only if +key+ does not already exist in the cache.
-  # If +raw+ is true, +value+ will not be Marshalled.
-  #
-  # Readers should call this method in the event of a cache miss, not
-  # MemCache#set.
-
-  def add(key, value, expiry = 0, raw = false)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    value = Marshal.dump value unless raw
-    with_server(key) do |server, cache_key|
-      logger.debug { "add #{key} to #{server}: #{value ? value.to_s.size : 'nil'}" } if logger
-      command = "add #{cache_key} 0 #{expiry} #{value.to_s.size}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-        result
-      end
-    end
-  end
-  
-  ##
-  # Add +key+ to the cache with value +value+ that expires in +expiry+
-  # seconds, but only if +key+ already exists in the cache.
-  # If +raw+ is true, +value+ will not be Marshalled.
-  def replace(key, value, expiry = 0, raw = false)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    value = Marshal.dump value unless raw
-    with_server(key) do |server, cache_key|
-      logger.debug { "replace #{key} to #{server}: #{value ? value.to_s.size : 'nil'}" } if logger
-      command = "replace #{cache_key} 0 #{expiry} #{value.to_s.size}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-        result
-      end
-    end
-  end
-
-  ##
-  # Append - 'add this data to an existing key after existing data'
-  # Please note the value is always passed to memcached as raw since it
-  # doesn't make a lot of sense to concatenate marshalled data together.
-  def append(key, value)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    with_server(key) do |server, cache_key|
-      logger.debug { "append #{key} to #{server}: #{value ? value.to_s.size : 'nil'}" } if logger
-      command = "append #{cache_key} 0 0 #{value.to_s.size}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-        result
-      end
-    end
-  end
-
-  ##
-  # Prepend - 'add this data to an existing key before existing data'
-  # Please note the value is always passed to memcached as raw since it
-  # doesn't make a lot of sense to concatenate marshalled data together.
-  def prepend(key, value)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    with_server(key) do |server, cache_key|
-      logger.debug { "prepend #{key} to #{server}: #{value ? value.to_s.size : 'nil'}" } if logger
-      command = "prepend #{cache_key} 0 0 #{value.to_s.size}#{noreply}\r\n#{value}\r\n"
-
-      with_socket_management(server) do |socket|
-        socket.write command
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-        result
-      end
-    end
-  end
-
-  ##
-  # Removes +key+ from the cache in +expiry+ seconds.
-
-  def delete(key, expiry = 0)
-    raise MemCacheError, "Update of readonly cache" if @readonly
-    with_server(key) do |server, cache_key|
-      with_socket_management(server) do |socket|
-        logger.debug { "delete #{cache_key} on #{server}" } if logger
-        socket.write "delete #{cache_key} #{expiry}#{noreply}\r\n"
-        break nil if @no_reply
-        result = socket.gets
-        raise_on_error_response! result
-        result
-      end
-    end
-  end
-
-  ##
-  # Flush the cache from all memcache servers.
-  # A non-zero value for +delay+ will ensure that the flush
-  # is propogated slowly through your memcached server farm.
-  # The Nth server will be flushed N*delay seconds from now,
-  # asynchronously so this method returns quickly.
-  # This prevents a huge database spike due to a total
-  # flush all at once.
-
-  def flush_all(delay=0)
-    raise MemCacheError, 'No active servers' unless active?
-    raise MemCacheError, "Update of readonly cache" if @readonly
-
-    begin
-      delay_time = 0
-      @servers.each do |server|
-        with_socket_management(server) do |socket|
-          logger.debug { "flush_all #{delay_time} on #{server}" } if logger
-          if delay == 0 # older versions of memcached will fail silently otherwise
-            socket.write "flush_all#{noreply}\r\n"
-          else
-            socket.write "flush_all #{delay_time}#{noreply}\r\n"
-          end
-          break nil if @no_reply
-          result = socket.gets
-          raise_on_error_response! result
-          result
-        end
-        delay_time += delay
-      end
-    rescue IndexError => err
-      handle_error nil, err
-    end
-  end
-
-  ##
-  # Reset the connection to all memcache servers.  This should be called if
-  # there is a problem with a cache lookup that might have left the connection
-  # in a corrupted state.
-
-  def reset
-    @servers.each { |server| server.close }
-  end
-
-  ##
-  # Returns statistics for each memcached server.  An explanation of the
-  # statistics can be found in the memcached docs:
-  #
-  # http://code.sixapart.com/svn/memcached/trunk/server/doc/protocol.txt
-  #
-  # Example:
-  #
-  #   >> pp CACHE.stats
-  #   {"localhost:11211"=>
-  #     {"bytes"=>4718,
-  #      "pid"=>20188,
-  #      "connection_structures"=>4,
-  #      "time"=>1162278121,
-  #      "pointer_size"=>32,
-  #      "limit_maxbytes"=>67108864,
-  #      "cmd_get"=>14532,
-  #      "version"=>"1.2.0",
-  #      "bytes_written"=>432583,
-  #      "cmd_set"=>32,
-  #      "get_misses"=>0,
-  #      "total_connections"=>19,
-  #      "curr_connections"=>3,
-  #      "curr_items"=>4,
-  #      "uptime"=>1557,
-  #      "get_hits"=>14532,
-  #      "total_items"=>32,
-  #      "rusage_system"=>0.313952,
-  #      "rusage_user"=>0.119981,
-  #      "bytes_read"=>190619}}
-  #   => nil
-
-  def stats
-    raise MemCacheError, "No active servers" unless active?
-    server_stats = {}
-
-    @servers.each do |server|
-      next unless server.alive?
-
-      with_socket_management(server) do |socket|
-        value = nil
-        socket.write "stats\r\n"
-        stats = {}
-        while line = socket.gets do
-          raise_on_error_response! line
-          break if line == "END\r\n"
-          if line =~ /\ASTAT ([\S]+) ([\w\.\:]+)/ then
-            name, value = $1, $2
-            stats[name] = case name
-                          when 'version'
-                            value
-                          when 'rusage_user', 'rusage_system' then
-                            seconds, microseconds = value.split(/:/, 2)
-                            microseconds ||= 0
-                            Float(seconds) + (Float(microseconds) / 1_000_000)
-                          else
-                            if value =~ /\A\d+\Z/ then
-                              value.to_i
-                            else
-                              value
-                            end
-                          end
-          end
-        end
-        server_stats["#{server.host}:#{server.port}"] = stats
-      end
-    end
-
-    raise MemCacheError, "No active servers" if server_stats.empty?
-    server_stats
-  end
-
-  ##
-  # Shortcut to get a value from the cache.
-
-  alias [] get
-
-  ##
-  # Shortcut to save a value in the cache.  This method does not set an
-  # expiration on the entry.  Use set to specify an explicit expiry.
-
-  def []=(key, value)
-    set key, value
-  end
-
-  protected unless $TESTING
-
-  ##
-  # Create a key for the cache, incorporating the namespace qualifier if
-  # requested.
-
-  def make_cache_key(key)
-    if @autofix_keys and (key =~ /\s/ or (key.length + (namespace.nil? ? 0 : namespace.length)) > 250)
-      key = "#{Digest::SHA1.hexdigest(key)}-autofixed"
-    end
-
-    if namespace.nil? then
-      key
-    else
-      "#{@namespace}#{@namespace_separator}#{key}"
-    end
-  end
-
-  ##
-  # Returns an interoperable hash value for +key+.  (I think, docs are
-  # sketchy for down servers).
-
-  def hash_for(key)
-    Zlib.crc32(key)
-  end
-
-  ##
-  # Pick a server to handle the request based on a hash of the key.
-
-  def get_server_for_key(key, options = {})
-    raise ArgumentError, "illegal character in key #{key.inspect}" if
-      key =~ /\s/
-    raise ArgumentError, "key too long #{key.inspect}" if key.length > 250
-    raise MemCacheError, "No servers available" if @servers.empty?
-    return @servers.first if @servers.length == 1
-
-    hkey = hash_for(key)
-
-    20.times do |try|
-      entryidx = Continuum.binary_search(@continuum, hkey)
-      server = @continuum[entryidx].server
-      return server if server.alive?
-      break unless failover
-      hkey = hash_for "#{try}#{key}"
-    end
-    
-    raise MemCacheError, "No servers available"
-  end
-
-  ##
-  # Performs a raw decr for +cache_key+ from +server+.  Returns nil if not
-  # found.
-
-  def cache_decr(server, cache_key, amount)
-    with_socket_management(server) do |socket|
-      socket.write "decr #{cache_key} #{amount}#{noreply}\r\n"
-      break nil if @no_reply
-      text = socket.gets
-      raise_on_error_response! text
-      return nil if text == "NOT_FOUND\r\n"
-      return text.to_i
-    end
-  end
-
-  ##
-  # Fetches the raw data for +cache_key+ from +server+.  Returns nil on cache
-  # miss.
-
-  def cache_get(server, cache_key)
-    with_socket_management(server) do |socket|
-      socket.write "get #{cache_key}\r\n"
-      keyline = socket.gets # "VALUE <key> <flags> <bytes>\r\n"
-
-      if keyline.nil? then
-        server.close
-        raise MemCacheError, "lost connection to #{server.host}:#{server.port}"
-      end
-
-      raise_on_error_response! keyline
-      return nil if keyline == "END\r\n"
-
-      unless keyline =~ /(\d+)\r/ then
-        server.close
-        raise MemCacheError, "unexpected response #{keyline.inspect}"
-      end
-      value = socket.read $1.to_i
-      socket.read 2 # "\r\n"
-      socket.gets   # "END\r\n"
-      return value
-    end
-  end
-
-  def gets(key, raw = false)
-    with_server(key) do |server, cache_key|
-      logger.debug { "gets #{key} from #{server.inspect}" } if logger
-      result = with_socket_management(server) do |socket|
-        socket.write "gets #{cache_key}\r\n"
-        keyline = socket.gets # "VALUE <key> <flags> <bytes> <cas token>\r\n"
-
-        if keyline.nil? then
-          server.close
-          raise MemCacheError, "lost connection to #{server.host}:#{server.port}"
-        end
-
-        raise_on_error_response! keyline
-        return nil if keyline == "END\r\n"
-
-        unless keyline =~ /(\d+) (\w+)\r/ then
-          server.close
-          raise MemCacheError, "unexpected response #{keyline.inspect}"
-        end
-        value = socket.read $1.to_i
-        socket.read 2 # "\r\n"
-        socket.gets   # "END\r\n"
-        [value, $2]
-      end
-      result[0] = Marshal.load result[0] unless raw
-      result
-    end
-  rescue TypeError => err
-    handle_error nil, err
-  end
-
-
-  ##
-  # Fetches +cache_keys+ from +server+ using a multi-get.
-
-  def cache_get_multi(server, cache_keys)
-    with_socket_management(server) do |socket|
-      values = {}
-      socket.write "get #{cache_keys}\r\n"
-
-      while keyline = socket.gets do
-        return values if keyline == "END\r\n"
-        raise_on_error_response! keyline
-
-        unless keyline =~ /\AVALUE (.+) (.+) (.+)/ then
-          server.close
-          raise MemCacheError, "unexpected response #{keyline.inspect}"
-        end
-
-        key, data_length = $1, $3
-        values[$1] = socket.read data_length.to_i
-        socket.read(2) # "\r\n"
-      end
-
-      server.close
-      raise MemCacheError, "lost connection to #{server.host}:#{server.port}" # TODO: retry here too
-    end
-  end
-
-  ##
-  # Performs a raw incr for +cache_key+ from +server+.  Returns nil if not
-  # found.
-
-  def cache_incr(server, cache_key, amount)
-    with_socket_management(server) do |socket|
-      socket.write "incr #{cache_key} #{amount}#{noreply}\r\n"
-      break nil if @no_reply
-      text = socket.gets
-      raise_on_error_response! text
-      return nil if text == "NOT_FOUND\r\n"
-      return text.to_i
-    end
-  end
-
-  ##
-  # Gets or creates a socket connected to the given server, and yields it
-  # to the block, wrapped in a mutex synchronization if @multithread is true.
-  #
-  # If a socket error (SocketError, SystemCallError, IOError) or protocol error
-  # (MemCacheError) is raised by the block, closes the socket, attempts to
-  # connect again, and retries the block (once).  If an error is again raised,
-  # reraises it as MemCacheError.
-  #
-  # If unable to connect to the server (or if in the reconnect wait period),
-  # raises MemCacheError.  Note that the socket connect code marks a server
-  # dead for a timeout period, so retrying does not apply to connection attempt
-  # failures (but does still apply to unexpectedly lost connections etc.).
-
-  def with_socket_management(server, &block)
-    check_multithread_status!
-
-    @mutex.lock if @multithread
-    retried = false
-
-    begin
-      socket = server.socket
-
-      # Raise an IndexError to show this server is out of whack. If were inside
-      # a with_server block, we'll catch it and attempt to restart the operation.
-
-      raise IndexError, "No connection to server (#{server.status})" if socket.nil?
-
-      block.call(socket)
-
-    rescue SocketError, Errno::EAGAIN, Timeout::Error => err
-      logger.warn { "Socket failure: #{err.message}" } if logger
-      server.mark_dead(err)
-      handle_error(server, err)
-
-    rescue MemCacheError, SystemCallError, IOError => err
-      logger.warn { "Generic failure: #{err.class.name}: #{err.message}" } if logger
-      handle_error(server, err) if retried || socket.nil?
-      retried = true
-      retry
-    end
-  ensure
-    @mutex.unlock if @multithread
-  end
-
-  def with_server(key)
-    retried = false
-    begin
-      server, cache_key = request_setup(key)
-      yield server, cache_key
-    rescue IndexError => e
-      logger.warn { "Server failed: #{e.class.name}: #{e.message}" } if logger
-      if !retried && @servers.size > 1
-        logger.info { "Connection to server #{server.inspect} DIED! Retrying operation..." } if logger
-        retried = true
-        retry
-      end
-      handle_error(nil, e)
-    end
-  end
-
-  ##
-  # Handles +error+ from +server+.
-
-  def handle_error(server, error)
-    raise error if error.is_a?(MemCacheError)
-    server.close if server
-    new_error = MemCacheError.new error.message
-    new_error.set_backtrace error.backtrace
-    raise new_error
-  end
-
-  def noreply
-    @no_reply ? ' noreply' : ''
-  end
-
-  ##
-  # Performs setup for making a request with +key+ from memcached.  Returns
-  # the server to fetch the key from and the complete key to use.
-
-  def request_setup(key)
-    raise MemCacheError, 'No active servers' unless active?
-    cache_key = make_cache_key key
-    server = get_server_for_key cache_key
-    return server, cache_key
-  end
-
-  def raise_on_error_response!(response)
-    if response =~ /\A(?:CLIENT_|SERVER_)?ERROR(.*)/
-      raise MemCacheError, $1.strip
-    end
-  end
-
-  def create_continuum_for(servers)
-    total_weight = servers.inject(0) { |memo, srv| memo + srv.weight }
-    continuum = []
-
-    servers.each do |server|
-      entry_count_for(server, servers.size, total_weight).times do |idx|
-        hash = Digest::SHA1.hexdigest("#{server.host}:#{server.port}:#{idx}")
-        value = Integer("0x#{hash[0..7]}")
-        continuum << Continuum::Entry.new(value, server)
-      end
-    end
-
-    continuum.sort { |a, b| a.value <=> b.value }
-  end
-
-  def entry_count_for(server, total_servers, total_weight)
-    ((total_servers * Continuum::POINTS_PER_SERVER * server.weight) / Float(total_weight)).floor
-  end
-
-  def check_multithread_status!
-    return if @multithread
-
-    if Thread.current[:memcache_client] != self.object_id
-      raise MemCacheError, <<-EOM
-        You are accessing this memcache-client instance from multiple threads but have not enabled multithread support.
-        Normally:  MemCache.new(['localhost:11211'], :multithread => true)
-        In Rails:  config.cache_store = [:mem_cache_store, 'localhost:11211', { :multithread => true }]
-      EOM
-    end
-  end
-
-  ##
-  # This class represents a memcached server instance.
-
-  class Server
-
-    ##
-    # The amount of time to wait before attempting to re-establish a
-    # connection with a server that is marked dead.
-
-    RETRY_DELAY = 30.0
-
-    ##
-    # The host the memcached server is running on.
-
-    attr_reader :host
-
-    ##
-    # The port the memcached server is listening on.
-
-    attr_reader :port
-
-    ##
-    # The weight given to the server.
-
-    attr_reader :weight
-
-    ##
-    # The time of next retry if the connection is dead.
-
-    attr_reader :retry
-
-    ##
-    # A text status string describing the state of the server.
-
-    attr_reader :status
-
-    attr_reader :logger
-
-    ##
-    # Create a new MemCache::Server object for the memcached instance
-    # listening on the given host and port, weighted by the given weight.
-
-    def initialize(memcache, host, port = DEFAULT_PORT, weight = DEFAULT_WEIGHT)
-      raise ArgumentError, "No host specified" if host.nil? or host.empty?
-      raise ArgumentError, "No port specified" if port.nil? or port.to_i.zero?
-
-      @host   = host
-      @port   = port.to_i
-      @weight = weight.to_i
-
-      @sock   = nil
-      @retry  = nil
-      @status = 'NOT CONNECTED'
-      @timeout = memcache.timeout
-      @logger = memcache.logger
-    end
-
-    ##
-    # Return a string representation of the server object.
-
-    def inspect
-      "<MemCache::Server: %s:%d [%d] (%s)>" % [@host, @port, @weight, @status]
-    end
-
-    ##
-    # Check whether the server connection is alive.  This will cause the
-    # socket to attempt to connect if it isn't already connected and or if
-    # the server was previously marked as down and the retry time has
-    # been exceeded.
-
-    def alive?
-      !!socket
-    end
-
-    ##
-    # Try to connect to the memcached server targeted by this object.
-    # Returns the connected socket object on success or nil on failure.
-
-    def socket
-      return @sock if @sock and not @sock.closed?
-
-      @sock = nil
-
-      # If the host was dead, don't retry for a while.
-      return if @retry and @retry > Time.now
-
-      # Attempt to connect if not already connected.
-      begin
-        @sock = connect_to(@host, @port, @timeout)
-        @sock.setsockopt Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1
-        @retry  = nil
-        @status = 'CONNECTED'
-      rescue SocketError, SystemCallError, IOError => err
-        logger.warn { "Unable to open socket: #{err.class.name}, #{err.message}" } if logger
-        mark_dead err
-      end
-
-      return @sock
-    end
-
-    def connect_to(host, port, timeout=nil)
-      io = MemCache::BufferedIO.new(TCPSocket.new(host, port))
-      io.read_timeout = timeout
-      io
-    end
-
-    ##
-    # Close the connection to the memcached server targeted by this
-    # object.  The server is not considered dead.
-
-    def close
-      @sock.close if @sock && !@sock.closed?
-      @sock   = nil
-      @retry  = nil
-      @status = "NOT CONNECTED"
-    end
-
-    ##
-    # Mark the server as dead and close its socket.
-
-    def mark_dead(error)
-      @sock.close if @sock && !@sock.closed?
-      @sock   = nil
-      @retry  = Time.now + RETRY_DELAY
-
-      reason = "#{error.class.name}: #{error.message}"
-      @status = sprintf "%s:%s DEAD (%s), will retry at %s", @host, @port, reason, @retry
-      @logger.info { @status } if @logger
-    end
-
-  end
-
-  ##
-  # Base MemCache exception class.
-
-  class MemCacheError < RuntimeError; end
-
-  class BufferedIO < Net::BufferedIO # :nodoc:
-    BUFSIZE = 1024 * 16
-
-    if RUBY_VERSION < '1.9.1'
-      def rbuf_fill
-        begin
-          @rbuf << @io.read_nonblock(BUFSIZE)
-        rescue Errno::EWOULDBLOCK
-          retry unless @read_timeout
-          if IO.select([@io], nil, nil, @read_timeout)
-            retry
-          else
-            raise Timeout::Error, 'IO timeout'
-          end
-        end
-      end
-    end
-
-    def setsockopt(*args)
-      @io.setsockopt(*args)
-    end
-
-    def gets
-      readuntil("\n")
-    end
-  end
-
-end
-
-module Continuum
-  POINTS_PER_SERVER = 160 # this is the default in libmemcached
-
-  # Find the closest index in Continuum with value <= the given value
-  def self.binary_search(ary, value, &block)
-    upper = ary.size - 1
-    lower = 0
-    idx = 0
-
-    while(lower <= upper) do
-      idx = (lower + upper) / 2
-      comp = ary[idx].value <=> value
-
-      if comp == 0
-        return idx
-      elsif comp > 0
-        upper = idx - 1
-      else
-        lower = idx + 1
-      end
-    end
-    return upper
-  end
-
-  class Entry
-    attr_reader :value
-    attr_reader :server
-
-    def initialize(val, srv)
-      @value = val
-      @server = srv
-    end
-
-    def inspect
-      "<#{value}, #{server.host}:#{server.port}>"
-    end
-  end
-
-end