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# Copyright (C) 2014-2017 MongoDB, Inc.
#
# 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 'stringio'
module Mongo
module Grid
class File
# Encapsulates behaviour around GridFS chunks of file data.
#
# @since 2.0.0
class Chunk
# Name of the chunks collection.
#
# @since 2.0.0
COLLECTION = 'chunks'.freeze
# Default size for chunks of data.
#
# @since 2.0.0
DEFAULT_SIZE = (255 * 1024).freeze
# @return [ BSON::Document ] document The document to store for the
# chunk.
attr_reader :document
# Check chunk equality.
#
# @example Check chunk equality.
# chunk == other
#
# @param [ Object ] other The object ot compare to.
#
# @return [ true, false ] If the objects are equal.
#
# @since 2.0.0
def ==(other)
return false unless other.is_a?(Chunk)
document == other.document
end
# Get the BSON type for a chunk document.
#
# @example Get the BSON type.
# chunk.bson_type
#
# @return [ Integer ] The BSON type.
#
# @since 2.0.0
def bson_type
BSON::Hash::BSON_TYPE
end
# Get the chunk data.
#
# @example Get the chunk data.
# chunk.data
#
# @return [ BSON::Binary ] The chunk data.
#
# @since 2.0.0
def data
document[:data]
end
# Get the chunk id.
#
# @example Get the chunk id.
# chunk.id
#
# @return [ BSON::ObjectId ] The chunk id.
#
# @since 2.0.0
def id
document[:_id]
end
# Get the files id.
#
# @example Get the files id.
# chunk.files_id
#
# @return [ BSON::ObjectId ] The files id.
#
# @since 2.0.0
def files_id
document[:files_id]
end
# Get the chunk position.
#
# @example Get the chunk position.
# chunk.n
#
# @return [ Integer ] The chunk position.
#
# @since 2.0.0
def n
document[:n]
end
# Create the new chunk.
#
# @example Create the chunk.
# Chunk.new(document)
#
# @param [ BSON::Document ] document The document to create the chunk
# from.
#
# @since 2.0.0
def initialize(document)
@document = BSON::Document.new(:_id => BSON::ObjectId.new).merge(document)
end
# Conver the chunk to BSON for storage.
#
# @example Convert the chunk to BSON.
# chunk.to_bson
#
# @param [ BSON::ByteBuffer ] buffer The encoded BSON buffer to append to.
# @param [ true, false ] validating_keys Whether keys should be validated when serializing.
#
# @return [ String ] The raw BSON data.
#
# @since 2.0.0
def to_bson(buffer = BSON::ByteBuffer.new, validating_keys = BSON::Config.validating_keys?)
document.to_bson(buffer)
end
class << self
# Takes an array of chunks and assembles them back into the full
# piece of raw data.
#
# @example Assemble the chunks.
# Chunk.assemble(chunks)
#
# @param [ Array<Chunk> ] chunks The chunks.
#
# @return [ String ] The assembled data.
#
# @since 2.0.0
def assemble(chunks)
chunks.reduce(''){ |data, chunk| data << chunk.data.data }
end
# Split the provided data into multiple chunks.
#
# @example Split the data into chunks.
# Chunks.split(data)
#
# @param [ String, IO ] io The raw bytes.
# @param [ File::Info ] file_info The files collection file doc.
# @param [ Integer ] offset The offset.
#
# @return [ Array<Chunk> ] The chunks of the data.
#
# @since 2.0.0
def split(io, file_info, offset = 0)
io = StringIO.new(io) if io.is_a?(String)
parts = Enumerator.new { |y| y << io.read(file_info.chunk_size) until io.eof? }
parts.map.with_index do |bytes, n|
file_info.md5.update(bytes)
Chunk.new(
data: BSON::Binary.new(bytes),
files_id: file_info.id,
n: n + offset,
)
end
end
end
end
end
end
end
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