nim-serialization/serialization.nim

137 lines
4.7 KiB
Nim

import
faststreams, serialization/[object_serialization, errors]
export
faststreams, object_serialization, errors
template serializationFormatImpl(Name: untyped,
Reader, Writer, PreferedOutput: distinct type,
mimeTypeName: static string = "") {.dirty.} =
# This indirection is required in order to be able to generate the
# `mimeType` accessor template. Without the indirection, the template
# mechanism of Nim will try to expand the `mimeType` param in the position
# of the `mimeType` template name which will result in error.
type Name* = object
template ReaderType*(T: type Name): type = Reader
template WriterType*(T: type Name): type = Writer
template PreferedOutputType*(T: type Name): type = PreferedOutput
template mimeType*(T: type Name): string = mimeTypeName
template serializationFormat*(Name: untyped,
Reader, Writer, PreferedOutput: distinct type,
mimeType: static string = "") =
serializationFormatImpl(Name, Reader, Writer, PreferedOutput, mimeType)
proc encodeImpl(writer: var auto, value: auto) =
mixin writeValue, getOutput
writer.writeValue value
template encode*(Format: type, value: auto, params: varargs[untyped]): auto =
mixin init, WriterType, PreferedOutputType
var s = init OutputStream
# TODO:
# Remove this when statement once the following bug is fixed:
# https://github.com/nim-lang/Nim/issues/9996
when astToStr(params) != "":
var writer = init(WriterType(Format), s, params)
else:
var writer = init(WriterType(Format), s)
encodeImpl(writer, value)
s.getOutput PreferedOutputType(Format)
proc readValue*(reader: var auto, T: type): T =
mixin readValue
reader.readValue(result)
template decode*(Format: distinct type,
input: string,
RecordType: distinct type,
params: varargs[untyped]): auto =
# TODO, this is dusplicated only due to a Nim bug:
# If `input` was `string|openarray[byte]`, it won't match `seq[byte]`
mixin init, ReaderType
var stream = memoryStream(input)
# TODO:
# Remove this when statement once the following bug is fixed:
# https://github.com/nim-lang/Nim/issues/9996
when astToStr(params) != "":
var reader = init(ReaderType(Format), stream, params)
else:
var reader = init(ReaderType(Format), stream)
reader.readValue(RecordType)
template decode*(Format: distinct type,
input: openarray[byte],
RecordType: distinct type,
params: varargs[untyped]): auto =
# TODO, this is dusplicated only due to a Nim bug:
# If `input` was `string|openarray[byte]`, it won't match `seq[byte]`
mixin init, ReaderType
var stream = memoryStream(input)
# TODO:
# Remove this when statement once the following bug is fixed:
# https://github.com/nim-lang/Nim/issues/9996
when astToStr(params) != "":
var reader = init(ReaderType(Format), stream, params)
else:
var reader = init(ReaderType(Format), stream)
reader.readValue(RecordType)
template loadFile*(Format: distinct type,
filename: string,
RecordType: distinct type,
params: varargs[untyped]): auto =
mixin init, ReaderType
var stream = openFile(filename)
try:
# TODO:
# Remove this when statement once the following bug is fixed:
# https://github.com/nim-lang/Nim/issues/9996
when astToStr(params) != "":
var reader = init(ReaderType(Format), stream, params)
else:
var reader = init(ReaderType(Format), stream)
reader.readValue(RecordType)
finally:
# TODO: destructors
if not stream.isNil:
stream[].close()
template loadFile*[RecordType](Format: type,
filename: string,
record: var RecordType,
params: varargs[untyped]) =
record = loadFile(Format, filename, RecordType, params)
template saveFile*(Format: type, filename: string, args: varargs[untyped]) =
when false:
# TODO use faststreams output stream
discard
else:
let bytes = Format.encode(args)
writeFile(filename, cast[string](bytes))
template borrowSerialization*(Alias: distinct type,
OriginalType: distinct type) {.dirty.} =
proc writeValue*[Writer](writer: var Writer, value: Alias) =
mixin writeValue
writeValue(writer, OriginalType value)
proc readValue*[Reader](reader: var Reader, value: var Alias) =
mixin readValue
value = Alias reader.readValue(OriginalType)
template appendValue*(stream: OutputStreamVar, Format: type, value: auto) =
mixin WriterType, init, writeValue
var writer = init(WriterType(Format), stream)
writeValue writer, value