NimYAML/private/presenter.nim

667 lines
27 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.
import typetraits
type
DumperState = enum
dBlockExplicitMapKey, dBlockImplicitMapKey, dBlockMapValue,
dBlockInlineMap, dBlockSequenceItem, dFlowImplicitMapKey, dFlowMapValue,
dFlowExplicitMapKey, dFlowSequenceItem, dFlowMapStart,
dFlowSequenceStart
ScalarStyle = enum
sLiteral, sFolded, sPlain, sDoubleQuoted
proc inspect(scalar: string, indentation: int,
words, lines: var seq[tuple[start, finish: int]]):
ScalarStyle {.raises: [].} =
var
inLine = false
inWord = false
multipleSpaces = true
curWord, curLine: tuple[start, finish: int]
canUseFolded = true
canUseLiteral = true
canUsePlain = scalar.len > 0 and scalar[0] notin {'@', '`'}
for i, c in scalar:
case c
of ' ':
if inWord:
if not multipleSpaces:
curWord.finish = i - 1
inWord = false
else:
multipleSpaces = true
inWord = true
if not inLine:
inLine = true
curLine.start = i
# space at beginning of line will preserve previous and next
# linebreak. that is currently too complex to handle.
canUseFolded = false
of '\l':
canUsePlain = false # we don't use multiline plain scalars
curWord.finish = i - 1
if curWord.finish - curWord.start + 1 > 80 - indentation:
return if canUsePlain: sPlain else: sDoubleQuoted
words.add(curWord)
inWord = false
curWord.start = i + 1
multipleSpaces = true
if not inLine: curLine.start = i
inLine = false
curLine.finish = i - 1
if curLine.start - curLine.finish + 1 > 80 - indentation:
canUseLiteral = false
lines.add(curLine)
else:
if c in {'{', '}', '[', ']', ',', '#', '-', ':', '?', '%', '"',
'\''} or c.ord < 32: canUsePlain = false
if not inLine:
curLine.start = i
inLine = true
if not inWord:
if not multipleSpaces:
if curWord.finish - curWord.start + 1 > 80 - indentation:
return if canUsePlain: sPlain else: sDoubleQuoted
words.add(curWord)
curWord.start = i
inWord = true
multipleSpaces = false
if inWord:
curWord.finish = scalar.len - 1
if curWord.finish - curWord.start + 1 > 80 - indentation:
return if canUsePlain: sPlain else: sDoubleQuoted
words.add(curWord)
if inLine:
curLine.finish = scalar.len - 1
if curLine.finish - curLine.start + 1 > 80 - indentation:
canUseLiteral = false
lines.add(curLine)
if scalar.len <= 80 - indentation:
result = if canUsePlain: sPlain else: sDoubleQuoted
elif canUseLiteral: result = sLiteral
elif canUseFolded: result = sFolded
elif canUsePlain: result = sPlain
else: result = sDoubleQuoted
proc writeDoubleQuoted(scalar: string, s: Stream, indentation: int)
{.raises: [YamlPresenterOutputError].} =
var curPos = indentation
try:
s.write('"')
curPos.inc()
for c in scalar:
if curPos == 79:
s.write("\\\l")
s.write(repeat(' ', indentation))
curPos = indentation
if c == ' ':
s.write('\\')
curPos.inc()
case c
of '"':
s.write("\\\"")
curPos.inc(2)
of '\l':
s.write("\\n")
curPos.inc(2)
of '\t':
s.write("\\t")
curPos.inc(2)
of '\\':
s.write("\\\\")
curPos.inc(2)
else:
if ord(c) < 32:
s.write("\\x" & toHex(ord(c), 2))
curPos.inc(4)
else:
s.write(c)
curPos.inc()
s.write('"')
except:
var e = newException(YamlPresenterOutputError,
"Error while writing to output stream")
e.parent = getCurrentException()
raise e
proc writeDoubleQuotedJson(scalar: string, s: Stream)
{.raises: [YamlPresenterOutputError].} =
try:
s.write('"')
for c in scalar:
case c
of '"': s.write("\\\"")
of '\\': s.write("\\\\")
of '\l': s.write("\\n")
of '\t': s.write("\\t")
of '\f': s.write("\\f")
of '\b': s.write("\\b")
else:
if ord(c) < 32:
s.write("\\u" & toHex(ord(c), 4))
else:
s.write(c)
s.write('"')
except:
var e = newException(YamlPresenterOutputError,
"Error while writing to output stream")
e.parent = getCurrentException()
raise e
proc writeLiteral(scalar: string, indentation, indentStep: int, s: Stream,
lines: seq[tuple[start, finish: int]])
{.raises: [YamlPresenterOutputError].} =
try:
s.write('|')
if scalar[^1] != '\l': s.write('-')
if scalar[0] in [' ', '\t']: s.write($indentStep)
for line in lines:
s.write('\l')
s.write(repeat(' ', indentation + indentStep))
if line.finish >= line.start:
s.write(scalar[line.start .. line.finish])
except:
var e = newException(YamlPresenterOutputError,
"Error while writing to output stream")
e.parent = getCurrentException()
raise e
proc writeFolded(scalar: string, indentation, indentStep: int, s: Stream,
words: seq[tuple[start, finish: int]])
{.raises: [YamlPresenterOutputError].} =
try:
s.write("|-")
var curPos = 80
for word in words:
if word.start > 0 and scalar[word.start - 1] == '\l':
s.write("\l\l")
s.write(repeat(' ', indentation + indentStep))
curPos = indentation + indentStep
elif curPos + (word.finish - word.start) > 80:
s.write('\l')
s.write(repeat(' ', indentation + indentStep))
curPos = indentation + indentStep
else:
s.write(' ')
curPos.inc()
s.write(scalar[word.start .. word.finish])
curPos += word.finish - word.start + 1
except:
var e = newException(YamlPresenterOutputError,
"Error while writing to output stream")
e.parent = getCurrentException()
raise e
template safeWrite(s: string or char) {.dirty.} =
try:
target.write(s)
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
proc startItem(target: Stream, style: PresentationStyle, indentation: int,
state: var DumperState, isObject: bool)
{.raises: [YamlPresenterOutputError].} =
try:
case state
of dBlockMapValue:
target.write('\l')
target.write(repeat(' ', indentation))
if isObject or style == psCanonical:
target.write("? ")
state = dBlockExplicitMapKey
else:
state = dBlockImplicitMapKey
of dBlockInlineMap:
state = dBlockImplicitMapKey
of dBlockExplicitMapKey:
target.write('\l')
target.write(repeat(' ', indentation))
target.write(": ")
state = dBlockMapValue
of dBlockImplicitMapKey:
target.write(": ")
state = dBlockMapValue
of dFlowExplicitMapKey:
if style != psMinimal:
target.write('\l')
target.write(repeat(' ', indentation))
target.write(": ")
state = dFlowMapValue
of dFlowMapValue:
if (isObject and style != psMinimal) or
style in [psJson, psCanonical]:
target.write(",\l" & repeat(' ', indentation))
if style == psJson:
state = dFlowImplicitMapKey
else:
target.write("? ")
state = dFlowExplicitMapKey
elif isObject and style == psMinimal:
target.write(", ? ")
state = dFlowExplicitMapKey
else:
target.write(", ")
state = dFlowImplicitMapKey
of dFlowMapStart:
if (isObject and style != psMinimal) or
style in [psJson, psCanonical]:
target.write("\l" & repeat(' ', indentation))
if style == psJson:
state = dFlowImplicitMapKey
else:
target.write("? ")
state = dFlowExplicitMapKey
else:
state = dFlowImplicitMapKey
of dFlowImplicitMapKey:
target.write(": ")
state = dFlowMapValue
of dBlockSequenceItem:
target.write('\l')
target.write(repeat(' ', indentation))
target.write("- ")
of dFlowSequenceStart:
case style
of psMinimal, psDefault:
discard
of psCanonical, psJson:
target.write('\l')
target.write(repeat(' ', indentation))
of psBlockOnly:
discard # can never happen
state = dFlowSequenceItem
of dFlowSequenceItem:
case style
of psMinimal, psDefault:
target.write(", ")
of psCanonical, psJson:
target.write(",\l")
target.write(repeat(' ', indentation))
of psBlockOnly:
discard # can never happen
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
proc anchorName(a: AnchorId): string {.raises: [].} =
result = ""
var i = int(a)
while i >= 0:
let j = i mod 36
if j < 26: result.add(char(j + ord('a')))
else: result.add(char(j + ord('0') - 26))
i -= 36
proc writeTagAndAnchor(target: Stream, tag: TagId, tagLib: TagLibrary,
anchor: AnchorId) {.raises:[YamlPresenterOutputError].} =
try:
if tag notin [yTagQuestionMark, yTagExclamationMark]:
let tagUri = tagLib.uri(tag)
if tagUri.startsWith(tagLib.secondaryPrefix):
target.write("!!")
target.write(tagUri[18..tagUri.high])
target.write(' ')
elif tagUri.startsWith("!"):
target.write(tagUri)
target.write(' ')
else:
target.write("!<")
target.write(tagUri)
target.write("> ")
if anchor != yAnchorNone:
target.write("&")
target.write(anchorName(anchor))
target.write(' ')
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
proc present*(s: var YamlStream, target: Stream, tagLib: TagLibrary,
style: PresentationStyle = psDefault,
indentationStep: int = 2) =
var
indentation = 0
levels = newSeq[DumperState]()
cached = initQueue[YamlStreamEvent]()
while cached.len > 0 or not s.finished():
let item = if cached.len > 0: cached.dequeue else: s.next()
case item.kind
of yamlStartDocument:
if style != psJson:
# TODO: tag directives
try:
target.write("%YAML 1.2\l")
if tagLib.secondaryPrefix != yamlTagRepositoryPrefix:
target.write("%TAG !! " &
tagLib.secondaryPrefix & '\l')
target.write("--- ")
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
of yamlScalar:
if levels.len == 0:
if style != psJson:
safeWrite('\l')
else:
startItem(target, style, indentation, levels[levels.high],
false)
if style != psJson:
writeTagAndAnchor(target,
item.scalarTag, tagLib, item.scalarAnchor)
if style == psJson:
let hint = guessType(item.scalarContent)
if item.scalarTag in [yTagQuestionMark, yTagBoolean] and
hint in [yTypeBoolTrue, yTypeBoolFalse]:
if hint == yTypeBoolTrue:
safeWrite("true")
else:
safeWrite("false")
elif item.scalarTag in [yTagQuestionMark, yTagNull] and
hint == yTypeNull:
safeWrite("null")
elif item.scalarTag in [yTagQuestionMark, yTagInteger] and
hint == yTypeInteger:
safeWrite(item.scalarContent)
elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
hint in [yTypeFloatInf, yTypeFloatNaN]:
raise newException(YamlPresenterJsonError,
"Infinity and not-a-number values cannot be presented as JSON!")
elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
hint == yTypeFloat:
safeWrite(item.scalarContent)
else:
writeDoubleQuotedJson(item.scalarContent, target)
elif style == psCanonical:
writeDoubleQuoted(item.scalarContent, target,
indentation + indentationStep)
else:
var words, lines = newSeq[tuple[start, finish: int]]()
case item.scalarContent.inspect(indentation + indentationStep,
words, lines)
of sLiteral: writeLiteral(item.scalarContent, indentation,
indentationStep, target, lines)
of sFolded: writeFolded(item.scalarContent, indentation,
indentationStep, target, words)
of sPlain: safeWrite(item.scalarContent)
of sDoubleQuoted: writeDoubleQuoted(item.scalarContent, target,
indentation + indentationStep)
of yamlAlias:
if style == psJson:
raise newException(YamlPresenterJsonError,
"Alias not allowed in JSON output")
assert levels.len > 0
startItem(target, style, indentation, levels[levels.high], false)
try:
target.write('*')
target.write(cast[byte]('a') + cast[byte](item.aliasTarget))
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
of yamlStartSequence:
var nextState: DumperState
case style
of psDefault:
var length = 0
while true:
assert(not(s.finished()))
let next = s.next()
cached.enqueue(next)
case next.kind
of yamlScalar:
length += 2 + next.scalarContent.len
of yamlAlias:
length += 6
of yamlEndSequence:
break
else:
length = high(int)
break
nextState = if length <= 60: dFlowSequenceStart else:
dBlockSequenceItem
of psJson:
if levels.len > 0 and levels[levels.high] in
[dFlowMapStart, dFlowMapValue]:
raise newException(YamlPresenterJsonError,
"Cannot have sequence as map key in JSON output!")
nextState = dFlowSequenceStart
of psMinimal, psCanonical:
nextState = dFlowSequenceStart
of psBlockOnly:
nextState = dBlockSequenceItem
if levels.len == 0:
if nextState == dBlockSequenceItem:
if style != psJson:
writeTagAndAnchor(target,
item.seqTag, tagLib, item.seqAnchor)
else:
if style != psJson:
writeTagAndAnchor(target,
item.seqTag, tagLib, item.seqAnchor)
safeWrite('\l')
indentation += indentationStep
else:
startItem(target, style, indentation, levels[levels.high], true)
if style != psJson:
writeTagAndAnchor(target,
item.seqTag, tagLib, item.seqAnchor)
indentation += indentationStep
if nextState == dFlowSequenceStart:
safeWrite('[')
if levels.len > 0 and style in [psJson, psCanonical] and
levels[levels.high] in
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
indentation += indentationStep
levels.add(nextState)
of yamlStartMap:
var nextState: DumperState
case style
of psDefault:
type MapParseState = enum
mpInitial, mpKey, mpValue, mpNeedBlock
var mps: MapParseState = mpInitial
while mps != mpNeedBlock:
case s.peek().kind
of yamlScalar, yamlAlias:
case mps
of mpInitial: mps = mpKey
of mpKey: mps = mpValue
else: mps = mpNeedBlock
of yamlEndMap:
break
else:
mps = mpNeedBlock
nextState = if mps == mpNeedBlock: dBlockMapValue else:
dBlockInlineMap
of psMinimal:
nextState = dFlowMapStart
of psCanonical:
nextState = dFlowMapStart
of psJson:
if levels.len > 0 and levels[levels.high] in
[dFlowMapStart, dFlowMapValue]:
raise newException(YamlPresenterJsonError,
"Cannot have map as map key in JSON output!")
nextState = dFlowMapStart
of psBlockOnly:
nextState = dBlockMapValue
if levels.len == 0:
if nextState == dBlockMapValue:
if style != psJson:
writeTagAndAnchor(target,
item.mapTag, tagLib, item.mapAnchor)
else:
if style != psJson:
safeWrite('\l')
writeTagAndAnchor(target,
item.mapTag, tagLib, item.mapAnchor)
indentation += indentationStep
else:
if nextState in [dBlockMapValue, dBlockImplicitMapKey]:
startItem(target, style, indentation, levels[levels.high],
true)
if style != psJson:
writeTagAndAnchor(target,
item.mapTag, tagLib, item.mapAnchor)
else:
startItem(target, style, indentation, levels[levels.high],
true)
if style != psJson:
writeTagAndAnchor(target,
item.mapTag, tagLib, item.mapAnchor)
indentation += indentationStep
if nextState == dFlowMapStart:
safeWrite('{')
if levels.len > 0 and style in [psJson, psCanonical] and
levels[levels.high] in
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
indentation += indentationStep
levels.add(nextState)
of yamlEndSequence:
assert levels.len > 0
case levels.pop()
of dFlowSequenceItem:
case style
of psDefault, psMinimal, psBlockOnly:
safeWrite(']')
of psJson, psCanonical:
indentation -= indentationStep
try:
target.write('\l')
target.write(repeat(' ', indentation))
target.write(']')
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
if levels.len == 0 or levels[levels.high] notin
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
continue
of dFlowSequenceStart:
if levels.len > 0 and style in [psJson, psCanonical] and
levels[levels.high] in
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
indentation -= indentationStep
safeWrite(']')
of dBlockSequenceItem:
discard
else:
assert false
indentation -= indentationStep
of yamlEndMap:
assert levels.len > 0
let level = levels.pop()
case level
of dFlowMapValue:
case style
of psDefault, psMinimal, psBlockOnly:
safeWrite('}')
of psJson, psCanonical:
indentation -= indentationStep
try:
target.write('\l')
target.write(repeat(' ', indentation))
target.write('}')
except:
var e = newException(YamlPresenterOutputError, "")
e.parent = getCurrentException()
raise e
if levels.len == 0 or levels[levels.high] notin
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
continue
of dFlowMapStart:
if levels.len > 0 and style in [psJson, psCanonical] and
levels[levels.high] in
[dBlockExplicitMapKey, dBlockMapValue,
dBlockImplicitMapKey, dBlockSequenceItem]:
indentation -= indentationStep
safeWrite('}')
of dBlockMapValue, dBlockInlineMap:
discard
else:
assert false
indentation -= indentationStep
of yamlEndDocument:
if finished(s): break
safeWrite("...\l")
proc transform*(input: Stream, output: Stream, style: PresentationStyle,
indentationStep: int = 2) =
var
taglib = initExtendedTagLibrary()
parser = newYamlParser(tagLib)
events = parser.parse(input)
try:
if style == psCanonical:
var specificTagEvents = iterator(): YamlStreamEvent =
for e in events:
var event = e
case event.kind
of yamlStartDocument, yamlEndDocument, yamlEndMap,
yamlAlias, yamlEndSequence:
discard
of yamlStartMap:
if event.mapTag in [yTagQuestionMark,
yTagExclamationMark]:
event.mapTag = yTagMap
of yamlStartSequence:
if event.seqTag in [yTagQuestionMark,
yTagExclamationMark]:
event.seqTag = yTagSequence
of yamlScalar:
if event.scalarTag == yTagQuestionMark:
case guessType(event.scalarContent)
of yTypeInteger:
event.scalarTag = yTagInteger
of yTypeFloat, yTypeFloatInf, yTypeFloatNaN:
event.scalarTag = yTagFloat
of yTypeBoolTrue, yTypeBoolFalse:
event.scalarTag = yTagBoolean
of yTypeNull:
event.scalarTag = yTagNull
of yTypeUnknown:
event.scalarTag = yTagString
elif event.scalarTag == yTagExclamationMark:
event.scalarTag = yTagString
yield event
var s = initYamlStream(specificTagEvents)
present(s, output, tagLib, style,
indentationStep)
else:
present(events, output, tagLib, style, indentationStep)
except YamlStreamError:
var e = getCurrentException()
while e.parent of YamlStreamError: e = e.parent
if e.parent of IOError:
raise (ref IOError)(e.parent)
elif e.parent of YamlParserError:
raise (ref YamlParserError)(e.parent)
else:
# never happens
assert(false)
except YamlPresenterJsonError:
raise (ref YamlPresenterJsonError)(getCurrentException())
except YamlPresenterOutputError:
raise (ref YamlPresenterOutputError)(getCurrentException())