Feature #5248 » patch.diff
| lib/pstore.rb | ||
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#
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# See PStore for documentation.
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require "fileutils"
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require "digest/md5"
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require "thread"
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#
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# PStore implements a file based persistence mechanism based on a Hash. User
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# Raises PStore::Error if the calling code is not in a PStore#transaction or
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# if the code is in a read-only PStore#transaction.
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#
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def in_transaction_wr()
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in_transaction()
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def in_transaction_wr
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in_transaction
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raise PStore::Error, "in read-only transaction" if @rdonly
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end
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private :in_transaction, :in_transaction_wr
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# be read-only. It will raise PStore::Error if called at any other time.
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#
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def []=(name, value)
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in_transaction_wr()
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in_transaction_wr
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@table[name] = value
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end
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#
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# be read-only. It will raise PStore::Error if called at any other time.
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#
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def delete(name)
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in_transaction_wr()
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in_transaction_wr
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@table.delete name
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end
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# Constant for relieving Ruby's garbage collector.
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EMPTY_STRING = ""
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EMPTY_MARSHAL_DATA = Marshal.dump({})
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EMPTY_MARSHAL_CHECKSUM = Digest::MD5.digest(EMPTY_MARSHAL_DATA)
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EMPTY_MARSHAL_CHECKSUM = EMPTY_MARSHAL_DATA.sum
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#
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# Open the specified filename (either in read-only mode or in
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if read_only
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begin
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table = load(file)
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if !table.is_a?(Hash)
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raise Error, "PStore file seems to be corrupted."
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end
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raise Error, "PStore file seems to be corrupted." unless table.is_a?(Hash)
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rescue EOFError
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# This seems to be a newly-created file.
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table = {}
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# This seems to be a newly-created file.
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table = {}
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checksum = empty_marshal_checksum
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size = empty_marshal_data.size
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size = empty_marshal_data.bytesize
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else
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table = load(data)
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checksum = Digest::MD5.digest(data)
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size = data.size
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if !table.is_a?(Hash)
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raise Error, "PStore file seems to be corrupted."
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end
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checksum = data.sum
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size = data.bytesize
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raise Error, "PStore file seems to be corrupted." unless table.is_a?(Hash)
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end
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data.replace(EMPTY_STRING)
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[table, checksum, size]
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end
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def on_windows?
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is_windows = RUBY_PLATFORM =~ /mswin/ ||
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RUBY_PLATFORM =~ /mingw/ ||
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RUBY_PLATFORM =~ /bccwin/ ||
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RUBY_PLATFORM =~ /wince/
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is_windows = RUBY_PLATFORM =~ /mswin|mingw|bccwin|wince/
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self.class.__send__(:define_method, :on_windows?) do
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is_windows
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end
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is_windows
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end
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# Check whether Marshal.dump supports the 'canonical' option. This option
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# makes sure that Marshal.dump always dumps data structures in the same order.
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# This is important because otherwise, the checksums that we generate may differ.
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def marshal_dump_supports_canonical_option?
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begin
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Marshal.dump(nil, -1, true)
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result = true
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rescue
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result = false
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end
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self.class.__send__(:define_method, :marshal_dump_supports_canonical_option?) do
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result
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end
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result
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end
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def save_data(original_checksum, original_file_size, file)
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# We only want to save the new data if the size or checksum has changed.
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# This results in less filesystem calls, which is good for performance.
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if marshal_dump_supports_canonical_option?
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new_data = Marshal.dump(@table, -1, true)
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else
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new_data = dump(@table)
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end
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new_checksum = Digest::MD5.digest(new_data)
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new_data = dump(@table)
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if new_data.size != original_file_size || new_checksum != original_checksum
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if new_data.bytesize != original_file_size || new_data.sum != original_checksum
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if @ultra_safe && !on_windows?
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# Windows doesn't support atomic file renames.
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save_data_with_atomic_file_rename_strategy(new_data, file)
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def save_data_with_fast_strategy(data, file)
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file.rewind
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file.truncate(0)
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file.write(data)
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file.truncate(data.bytesize)
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end
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# This method is just a wrapped around Marshal.dump
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# to allow subclass overriding used in YAML::Store.
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def dump(table) # :nodoc:
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def empty_marshal_data
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EMPTY_MARSHAL_DATA
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end
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def empty_marshal_checksum
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EMPTY_MARSHAL_CHECKSUM
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end
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| ... | ... | |
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# :enddoc:
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if __FILE__ == $0
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if __FILE__ == $PROGRAM_NAME
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db = PStore.new("/tmp/foo")
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db.transaction do
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p db.roots
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