NimYAML/private/streams.nim

92 lines
2.6 KiB
Nim

# NimYAML - YAML implementation in Nim
# (c) Copyright 2015 Felix Krause
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
when not defined(JS):
type IteratorYamlStream = ref object of YamlStream
backend: iterator(): YamlStreamEvent
proc initYamlStream*(backend: iterator(): YamlStreamEvent): YamlStream =
result = new(IteratorYamlStream)
result.peeked = false
result.isFinished = false
IteratorYamlStream(result).backend = backend
result.nextImpl = proc(s: YamlStream, e: var YamlStreamEvent): bool =
e = IteratorYamlStream(s).backend()
if finished(IteratorYamlStream(s).backend):
s.isFinished = true
result = false
else: result = true
type
BufferYamlStream = ref object of YamlStream
pos: int
buf: seq[YamlStreamEvent] not nil
proc newBufferYamlStream(): BufferYamlStream not nil =
BufferYamlStream(peeked: false, isFinished: false, buf: @[], pos: 0,
nextImpl: proc(s: YamlStream, e: var YamlStreamEvent): bool =
let bys = BufferYamlStream(s)
if bys.pos == bys.buf.len:
result = false
s.isFinished = true
else:
e = bys.buf[bys.pos]
inc(bys.pos)
result = true
)
proc next*(s: YamlStream): YamlStreamEvent =
if s.peeked:
s.peeked = false
shallowCopy(result, s.cached)
else:
yAssert(not s.isFinished)
try:
while true:
if s.nextImpl(s, result): break
yAssert(not s.isFinished)
except YamlStreamError:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur.parent
raise e
except Exception:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur
raise e
proc peek*(s: YamlStream): YamlStreamEvent =
if not s.peeked:
s.cached = s.next()
s.peeked = true
shallowCopy(result, s.cached)
proc `peek=`*(s: YamlStream, value: YamlStreamEvent) =
s.cached = value
s.peeked = true
proc finished*(s: YamlStream): bool =
if s.peeked: result = false
else:
try:
while true:
if s.isFinished: return true
if s.nextImpl(s, s.cached):
s.peeked = true
return false
except YamlStreamError:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur.parent
raise e
except Exception:
let cur = getCurrentException()
echo cur.getStackTrace()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur
raise e