120 lines
3.1 KiB
Ruby
120 lines
3.1 KiB
Ruby
# --
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# Copyright (C) 2008-2009 10gen Inc.
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#
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU Affero General Public License, version 3, as
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# published by the Free Software Foundation.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License
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# for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# ++
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require 'mutex_m'
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require 'mongo/util/byte_buffer'
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module XGen
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module Mongo
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module Driver
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# Implementation of the Babble OID. Object ids are not required by
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# Mongo, but they make certain operations more efficient.
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#
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# The driver does not automatically assign ids to records that are
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# inserted. (An upcoming feature will allow you to give an id "factory"
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# to a database and/or a collection.)
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#
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# 12 bytes
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# ---
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# 0 time
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# 1
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# 2
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# 3
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# 4 machine
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# 5
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# 6
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# 7 pid
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# 8
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# 9 inc
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# 10
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# 11
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class ObjectID
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MACHINE = ( val = rand(0x1000000); [val & 0xff, (val >> 8) & 0xff, (val >> 16) & 0xff] )
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PID = ( val = rand(0x10000); [val & 0xff, (val >> 8) & 0xff]; )
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LOCK = Object.new
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LOCK.extend Mutex_m
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@@index_time = Time.new.to_i
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@@index = 0
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# Given a string representation of an ObjectID, return a new ObjectID
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# with that value.
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def self.from_string(str)
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data = []
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i = str.to_i(16)
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while i > 0
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data << (i & 0xff)
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i >>= 8
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end
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self.new(data.reverse)
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end
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# +data+ is an array of bytes. If nil, a new id will be generated.
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# The time +t+ is only used for testing; leave it nil.
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def initialize(data=nil, t=nil)
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@data = data || generate_id(t)
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end
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def eql?(other)
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@data == other.to_a
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end
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alias_method :==, :eql?
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def to_a
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@data.dup
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end
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def to_s
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@data.collect { |b| '%02x' % b }.join
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end
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# (Would normally be private, but isn't so we can test it.)
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def generate_id(t=nil)
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t ||= Time.new.to_i
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buf = ByteBuffer.new
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buf.put_int(t & 0xffffffff)
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buf.put_array(MACHINE)
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buf.put_array(PID)
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i = index_for_time(t)
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buf.put(i & 0xff)
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buf.put((i >> 8) & 0xff)
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buf.put((i >> 16) & 0xff)
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buf.rewind
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buf.to_a.dup
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end
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# (Would normally be private, but isn't so we can test it.)
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def index_for_time(t)
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LOCK.mu_synchronize {
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if t != @@index_time
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@@index = 0
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@@index_time = t
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end
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retval = @@index
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@@index += 1
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retval
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}
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end
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end
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end
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end
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end
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