398 lines
10 KiB
Ruby
398 lines
10 KiB
Ruby
require 'mongo/types/dbref'
|
|
require 'mongo/types/objectid'
|
|
require 'mongo/util/ordered_hash'
|
|
require 'mongo/gridfs/chunk'
|
|
|
|
module XGen
|
|
module Mongo
|
|
module GridFS
|
|
|
|
# GridStore is an IO-like object that provides input and output for
|
|
# streams of data to Mongo. See Mongo's documentation about GridFS for
|
|
# storage implementation details.
|
|
#
|
|
# Example code:
|
|
#
|
|
# GridStore.open(database, 'filename', 'w') { |f|
|
|
# f.puts "Hello, world!"
|
|
# }
|
|
# GridStore.open(database, 'filename, 'r') { |f|
|
|
# puts f.read # => Hello, world!\n
|
|
# }
|
|
# GridStore.open(database, 'filename', 'w+") { |f|
|
|
# f.puts "But wait, there's more!"
|
|
# }
|
|
# GridStore.open(database, 'filename, 'r') { |f|
|
|
# puts f.read # => Hello, world!\nBut wait, there's more!\n
|
|
# }
|
|
class GridStore
|
|
|
|
include Enumerable
|
|
|
|
attr_accessor :filename
|
|
|
|
# Array of strings; may be +nil+
|
|
attr_accessor :aliases
|
|
|
|
# Default is 'text/plain'
|
|
attr_accessor :content_type
|
|
|
|
attr_reader :object_id, :upload_date
|
|
|
|
attr_reader :chunk_size
|
|
|
|
attr_accessor :lineno
|
|
|
|
class << self
|
|
|
|
def exist?(db, name)
|
|
db.collection('_files').find({'filename' => name}).next_object.nil?
|
|
end
|
|
|
|
def open(db, name, mode)
|
|
gs = self.new(db, name, mode)
|
|
result = nil
|
|
begin
|
|
result = yield gs if block_given?
|
|
ensure
|
|
gs.close
|
|
end
|
|
result
|
|
end
|
|
|
|
def read(db, name, length=nil, offset=nil)
|
|
GridStore.open(db, name, 'r') { |gs|
|
|
gs.seek(offset) if offset
|
|
gs.read(length)
|
|
}
|
|
end
|
|
|
|
def readlines(db, name, separator=$/)
|
|
GridStore.open(db, name, 'r') { |gs|
|
|
gs.readlines(separator)
|
|
}
|
|
end
|
|
|
|
def unlink(db, *names)
|
|
names.each { |name|
|
|
gs = GridStore.new(db, name)
|
|
gs.send(:delete_chunks)
|
|
db.collection('_files').remove('_id' => gs.object_id)
|
|
}
|
|
end
|
|
alias_method :delete, :unlink
|
|
|
|
end
|
|
|
|
#---
|
|
# ================================================================
|
|
#+++
|
|
|
|
# Mode may only be 'r', 'w', or 'w+'.
|
|
def initialize(db, name, mode='r')
|
|
@db, @filename, @mode = db, name, mode
|
|
|
|
doc = @db.collection('_files').find({'filename' => @filename}).next_object
|
|
if doc
|
|
@object_id = doc['_id']
|
|
@content_type = doc['contentType']
|
|
@chunk_size = doc['chunkSize']
|
|
@upload_date = doc['uploadDate']
|
|
@aliases = doc['aliases']
|
|
@length = doc['length']
|
|
fc_id = doc['next']
|
|
if fc_id
|
|
coll = @db.collection('_chunks')
|
|
row = coll.find({'_id' => fc_id.object_id}).next_object
|
|
@first_chunk = row ? Chunk.new(coll, row) : nil
|
|
else
|
|
@first_chunk = nil
|
|
end
|
|
else
|
|
@upload_date = Time.new
|
|
@chunk_size = Chunk::DEFAULT_CHUNK_SIZE
|
|
@content_type = 'text/plain'
|
|
@length = 0
|
|
end
|
|
|
|
case mode
|
|
when 'r'
|
|
@curr_chunk = @first_chunk
|
|
when 'w'
|
|
delete_chunks
|
|
@first_chunk = @curr_chunk = nil
|
|
when 'w+'
|
|
@curr_chunk = find_last_chunk
|
|
@curr_chunk.pos = @curr_chunk.data.length if @curr_chunk
|
|
end
|
|
|
|
@lineno = 0
|
|
@pushback_byte = nil
|
|
end
|
|
|
|
# Change chunk size. Can only change if the file is opened for write
|
|
# and the first chunk's size is zero.
|
|
def chunk_size=(size)
|
|
unless @mode[0] == ?w && @first_chunk == nil
|
|
raise "error: can only change chunk size if open for write and no data written."
|
|
end
|
|
@chunk_size = size
|
|
end
|
|
|
|
#---
|
|
# ================ reading ================
|
|
#+++
|
|
|
|
def getc
|
|
if @pushback_byte
|
|
byte = @pushback_byte
|
|
@pushback_byte = nil
|
|
byte
|
|
elsif eof?
|
|
nil
|
|
else
|
|
if @curr_chunk.eof?
|
|
@curr_chunk = @curr_chunk.next
|
|
end
|
|
@curr_chunk.getc
|
|
end
|
|
end
|
|
|
|
def gets(separator=$/)
|
|
str = ''
|
|
byte = getc
|
|
return nil if byte == nil # EOF
|
|
while byte != nil
|
|
s = byte.chr
|
|
str << s
|
|
break if s == separator
|
|
byte = getc
|
|
end
|
|
@lineno += 1
|
|
str
|
|
end
|
|
|
|
def read(len=nil, buf=nil)
|
|
buf ||= ''
|
|
byte = getc
|
|
while byte != nil && (len == nil || len > 0)
|
|
buf << byte.chr
|
|
len -= 1 if len
|
|
byte = getc if (len == nil || len > 0)
|
|
end
|
|
buf
|
|
end
|
|
|
|
def readchar
|
|
byte = getc
|
|
raise EOFError.new if byte == nil
|
|
byte
|
|
end
|
|
|
|
def readline(separator=$/)
|
|
line = gets
|
|
raise EOFError.new if line == nil
|
|
line
|
|
end
|
|
|
|
def readlines(separator=$/)
|
|
read.split(separator).collect { |line| "#{line}#{separator}" }
|
|
end
|
|
|
|
def each
|
|
line = gets
|
|
while line
|
|
yield line
|
|
line = gets
|
|
end
|
|
end
|
|
alias_method :each_line, :each
|
|
|
|
def each_byte
|
|
byte = getc
|
|
while byte
|
|
yield byte
|
|
byte = getc
|
|
end
|
|
end
|
|
|
|
def ungetc(byte)
|
|
@pushback_byte = byte
|
|
end
|
|
|
|
#---
|
|
# ================ writing ================
|
|
#+++
|
|
|
|
def putc(byte)
|
|
chunks = @db.collection('_chunks')
|
|
if @curr_chunk == nil
|
|
@first_chunk = @curr_chunk = Chunk.new(chunks, 'cn' => 1)
|
|
elsif @curr_chunk.pos == @chunk_size
|
|
prev_chunk = @curr_chunk
|
|
@curr_chunk = Chunk.new(chunks, 'cn' => prev_chunk.chunk_number + 1)
|
|
prev_chunk.next = @curr_chunk
|
|
prev_chunk.save
|
|
end
|
|
@curr_chunk.putc(byte)
|
|
end
|
|
|
|
def print(*objs)
|
|
objs = [$_] if objs == nil || objs.empty?
|
|
objs.each { |obj|
|
|
str = obj.to_s
|
|
str.each_byte { |byte| putc(byte) }
|
|
}
|
|
nil
|
|
end
|
|
|
|
def puts(*objs)
|
|
if objs == nil || objs.empty?
|
|
putc(10)
|
|
else
|
|
print(*objs.collect{ |obj|
|
|
str = obj.to_s
|
|
str << "\n" unless str =~ /\n$/
|
|
str
|
|
})
|
|
end
|
|
nil
|
|
end
|
|
|
|
def <<(obj)
|
|
write(obj.to_s)
|
|
end
|
|
|
|
# Writes +string+ as bytes and returns the number of bytes written.
|
|
def write(string)
|
|
raise "#@filename not opened for write" unless @mode[0] == ?w
|
|
count = 0
|
|
string.each_byte { |byte|
|
|
putc byte
|
|
count += 1
|
|
}
|
|
count
|
|
end
|
|
|
|
# A no-op.
|
|
def flush
|
|
end
|
|
|
|
#---
|
|
# ================ status ================
|
|
#+++
|
|
|
|
def eof
|
|
raise IOError.new("stream not open for reading") unless @mode[0] == ?r
|
|
@curr_chunk == nil || (@curr_chunk.eof? && !@curr_chunk.has_next?)
|
|
end
|
|
alias_method :eof?, :eof
|
|
|
|
#---
|
|
# ================ positioning ================
|
|
#+++
|
|
|
|
def rewind
|
|
if @curr_chunk != @first_chunk
|
|
@curr_chunk.save unless @curr_chunk == nil || @curr_chunk.empty?
|
|
@curr_chunk == @first_chunk
|
|
end
|
|
@curr_chunk.pos = 0
|
|
@lineno = 0
|
|
# TODO if writing, delete all other chunks on first write
|
|
end
|
|
|
|
def seek(pos, whence=IO::SEEK_SET)
|
|
# target_pos = case whence
|
|
# when IO::SEEK_CUR
|
|
# tell + pos
|
|
# when IO::SEEK_END
|
|
|
|
# @curr_chunk.save if @curr_chunk
|
|
# target_chunk_num = ((pos / @chunk_size) + 1).to_i
|
|
# target_chunk_pos = pos % @chunk_size
|
|
# if @curr_chunk == nil || @curr_chunk.chunk_number != target_chunk_num
|
|
# end
|
|
# @curr_chunk.pos = target_chunk_pos
|
|
# 0
|
|
# TODO
|
|
raise "not yet implemented"
|
|
end
|
|
|
|
def tell
|
|
return 0 unless @curr_chunk
|
|
@chunk_size * (@curr_chunk.chunk_number - 1) + @curr_chunk.pos
|
|
end
|
|
|
|
#---
|
|
# ================ closing ================
|
|
#+++
|
|
|
|
def close
|
|
if @mode[0] == ?w
|
|
if @curr_chunk
|
|
@curr_chunk.truncate
|
|
@curr_chunk.save
|
|
end
|
|
files = @db.collection('_files')
|
|
if @object_id
|
|
files.remove('_id' => @object_id)
|
|
else
|
|
@object_id = XGen::Mongo::Driver::ObjectID.new
|
|
end
|
|
files.insert(to_mongo_object)
|
|
end
|
|
@db = nil
|
|
end
|
|
|
|
def closed?
|
|
@db == nil
|
|
end
|
|
|
|
#---
|
|
# ================ protected ================
|
|
#+++
|
|
|
|
protected
|
|
|
|
def to_mongo_object
|
|
h = OrderedHash.new
|
|
h['_id'] = @object_id
|
|
h['filename'] = @filename
|
|
h['contentType'] = @content_type
|
|
h['length'] = @curr_chunk ? (@curr_chunk.chunk_number - 1) * @chunk_size + @curr_chunk.pos : 0
|
|
h['chunkSize'] = @chunk_size
|
|
h['uploadDate'] = @upload_date
|
|
h['aliases'] = @aliases
|
|
h['next'] = XGen::Mongo::Driver::DBRef.new(nil, nil, @db, '_chunks', @first_chunk.object_id) if @first_chunk
|
|
h
|
|
end
|
|
|
|
def find_last_chunk
|
|
chunk = @curr_chunk || @first_chunk
|
|
while chunk.has_next?
|
|
chunk = chunk.next
|
|
end
|
|
chunk
|
|
end
|
|
|
|
def save_chunk(chunk)
|
|
chunks = @db.collection('_chunks')
|
|
end
|
|
|
|
def delete_chunks
|
|
chunk = @first_chunk
|
|
coll = @db.collection('_chunks')
|
|
while chunk
|
|
next_chunk = chunk.next
|
|
coll.remove({'_id' => chunk.object_id})
|
|
chunk = next_chunk
|
|
end
|
|
@first_chunk = @curr_chunk = nil
|
|
end
|
|
|
|
end
|
|
end
|
|
end
|
|
end
|