117 lines
4.4 KiB
Ruby
117 lines
4.4 KiB
Ruby
# --
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# Copyright (C) 2008-2009 10gen Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ++
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require 'mongo/collection'
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require 'mongo/message'
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module XGen
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module Mongo
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module Driver
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# A query against a collection. A query's selector is a hash. See the
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# Mongo documentation for query details.
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class Query
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attr_accessor :number_to_skip, :number_to_return, :order_by
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# If true, $explain will be set in QueryMessage that uses this query.
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attr_accessor :explain
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# Either +nil+ or a hash (preferably an OrderedHash).
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attr_accessor :hint
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attr_reader :selector # writer defined below
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# sel :: A hash describing the query. See the Mongo docs for details.
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#
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# return_fields :: If not +nil+, a single field name or an array of
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# field names. Only those fields will be returned.
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# (Called :fields in calls to Collection#find.)
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#
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# number_to_skip :: Number of records to skip before returning
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# records. (Called :offset in calls to
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# Collection#find.) Default is 0.
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#
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# number_to_return :: Max number of records to return. (Called :limit
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# in calls to Collection#find.) Default is 0 (all
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# records).
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#
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# order_by :: If not +nil+, specifies record sort order. May be a
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# String, Hash, OrderedHash, or Array. If a string, the
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# results will be ordered by that field in ascending
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# order. If an array, it should be an array of field names
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# which will all be sorted in ascending order. If a hash,
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# it may be either a regular Hash or an OrderedHash. The
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# keys should be field names, and the values should be 1
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# (ascending) or -1 (descending). Note that if it is a
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# regular Hash then sorting by more than one field
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# probably will not be what you intend because key order
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# is not preserved. (order_by is called :sort in calls to
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# Collection#find.)
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#
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# hint :: If not +nil+, specifies query hint fields. Must be either
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# +nil+ or a hash (preferably an OrderedHash). See
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# Collection#hint.
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def initialize(sel={}, return_fields=nil, number_to_skip=0, number_to_return=0, order_by=nil, hint=nil)
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@number_to_skip, @number_to_return, @order_by, @hint =
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number_to_skip, number_to_return, order_by, hint
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@explain = nil
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self.selector = sel
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self.fields = return_fields
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end
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# Set query selector hash. If sel is a string, it will be used as a
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# $where clause. (See Mongo docs for details.)
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def selector=(sel)
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@selector = case sel
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when nil
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{}
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when String
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{"$where" => sel}
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when Hash
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sel
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end
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end
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# Set fields to return. If +val+ is +nil+ or empty, all fields will be
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# returned.
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def fields=(val)
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@fields = val
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@fields = nil if @fields && @fields.empty?
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end
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def fields
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case @fields
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when String
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{@fields => 1}
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when Array
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if @fields.length == 0
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nil
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else
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h = {}
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@fields.each { |field| h[field] = 1 }
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h
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end
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else # nil, anything else
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nil
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end
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end
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def contains_special_fields
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(@order_by != nil && @order_by.length > 0) || @explain || @hint
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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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