mbeckerle commented on a change in pull request #88: Daffodil 1919 separators URL: https://github.com/apache/incubator-daffodil/pull/88#discussion_r206571525
########## File path: daffodil-runtime1-unparser/src/main/scala/org/apache/daffodil/processors/unparsers/SeparatedSequenceUnparsers.scala ########## @@ -0,0 +1,423 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.daffodil.processors.unparsers + +import org.apache.daffodil.equality.TypeEqual +import org.apache.daffodil.exceptions.Assert +import org.apache.daffodil.processors.{ ElementRuntimeData, SequenceRuntimeData, TermRuntimeData } +import org.apache.daffodil.schema.annotation.props.SeparatorSuppressionPolicy +import org.apache.daffodil.schema.annotation.props.gen.{ SeparatorPosition } +import org.apache.daffodil.infoset.DIElement + +/** + * DFDL Spec. section 14.2.3 specifies only a few different behaviors + * for separator suppression. Each has an algorithm. + */ +sealed trait SeparatorSuppressionAlgorithm extends Serializable { + + /** + * Determines if we should suppress a zero length element and + * separator. + * + * Checks if the length is zero if necessary to decide. + * + * Returns Suppress or IfTrailing when the element is, in fact, zero length, + * and the algorithm wants those to be suppressed. + * Returns DoNotSuppress otherwise. + */ + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement): SeparatorSuppressionAction + + def shouldDoExtraSeparators = false + + def checkArrayPos(state: UState, maxRepeats: Long): Boolean = true + +} + +object SeparatorSuppressionAlgorithm { + type Type = SeparatorSuppressionAlgorithm + import SeparatorSuppressionAction._ + + object None extends Type { + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement) = Assert.usageError("not to be called.") + } + object FixedOrExpression extends Type { + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement) = DoNotSuppress + } + + class SuppressAnyEmpty(zeroLengthDetector: ZeroLengthDetector) extends Type { + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement) = { + val isZL = zeroLengthDetector.isZeroLength(infosetElement) + if (isZL) Suppress + else DoNotSuppress + } + } + + trait CheckArrayPosMixin { self: SeparatorSuppressionAlgorithm => + override def checkArrayPos(state: UState, maxRepeats: Long): Boolean = { + state.arrayPos <= maxRepeats + } + } + + class ImplicitSuppressAnyEmpty(zeroLengthDetector: ZeroLengthDetector) + extends SuppressAnyEmpty(zeroLengthDetector) + with CheckArrayPosMixin + + object ImplicitNeverOrNotPotentiallyTrailing extends Type + with CheckArrayPosMixin { + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement) = DoNotSuppress + + override def shouldDoExtraSeparators = true + + } + + class ImplicitPotentiallyTrailing(zeroLengthDetector: ZeroLengthDetector) extends Type + with CheckArrayPosMixin { + def shouldSuppressIfZeroLength(state: UState, infosetElement: DIElement) = { + val isZL = zeroLengthDetector.isZeroLength(infosetElement) + if (isZL) IfTrailing + else DoNotSuppress + } + } +} + +sealed trait SeparatorSuppressionAction extends Serializable +object SeparatorSuppressionAction { + type Type = SeparatorSuppressionAction + case object Suppress extends Type + case object DoNotSuppress extends Type + case object IfTrailing extends Type +} + +trait Separated { self: SequenceChildUnparser => + + def sep: Unparser + def spos: SeparatorPosition + def ssp: SeparatorSuppressionPolicy + def ssAlgorithm: SeparatorSuppressionAlgorithm + + val childProcessors = Seq(childUnparser, sep) +} + +class ScalarOrderedSeparatedSequenceChildUnparser( + childUnparser: Unparser, + srd: SequenceRuntimeData, + trd: TermRuntimeData, + val sep: Unparser, + val spos: SeparatorPosition, + val ssp: SeparatorSuppressionPolicy, + val ssAlgorithm: SeparatorSuppressionAlgorithm) + extends SequenceChildUnparser(childUnparser, srd, trd) + with Separated { + + override def unparse(state: UState) = childUnparser.unparse1(state) +} + +class RepOrderedSeparatedSequenceChildUnparser( + childUnparser: Unparser, + srd: SequenceRuntimeData, + erd: ElementRuntimeData, + val sep: Unparser, + val spos: SeparatorPosition, + val ssp: SeparatorSuppressionPolicy, // need for diagnostics perhaps + val ssAlgorithm: SeparatorSuppressionAlgorithm) + extends RepeatingChildUnparser(childUnparser, srd, erd) + with Separated { + + override def checkArrayPos(state: UState) = ssAlgorithm.checkArrayPos(state, maxRepeats(state)) +} + +class OrderedSeparatedSequenceUnparser( + rd: SequenceRuntimeData, + ssp: SeparatorSuppressionPolicy, + spos: SeparatorPosition, + sep: Unparser, + childUnparsersArg: Seq[SequenceChildUnparser]) + extends OrderedSequenceUnparserBase(rd, childUnparsersArg) { + + private val childUnparsers = childUnparsersArg.asInstanceOf[Seq[SequenceChildUnparser with Separated]] + + /** + * True if requires special treatment in the unparse processing loop, as occurrences + * of later sequence children can influence whether possible trailing separators + * from earlier sequence children are actually trailing or not. + */ + private type IPT = SeparatorSuppressionAlgorithm.ImplicitPotentiallyTrailing + + private val hasTrailingSeparatorSuppression = { + childUnparsers.last.ssAlgorithm.isInstanceOf[IPT] + } + + /** + * Unparses one occurrence. + */ + protected def unparseOne( + unparser: SequenceChildUnparser, + trd: TermRuntimeData, + state: UState): Unit = { + + if (trd.isRepresented) { + if ((spos eq SeparatorPosition.Prefix)) { + sep.unparse1(state) + } else if ((spos eq SeparatorPosition.Infix) && state.groupPos > 1) { + sep.unparse1(state) + } + } + + unparser.unparse1(state) + + if ((spos eq SeparatorPosition.Postfix) && trd.isRepresented) { + sep.unparse1(state) + } + } + + /** + * Unparses a zero-length occurrence, without the separator. This is so that + * any statements or other side-effects (discriminators, setVariable, etc.) + * will occur. + */ + private def unparseZeroLengthWithoutSeparatorForSideEffect( + unparser: SequenceChildUnparser, + trd: TermRuntimeData, + state: UState): Unit = { + // + // Unfortunately there's no way to confirm that this produced zero length + // because of the possible buffering going on in the unparser. + // We'd have to depend on intricate details of the unparser behavior to do this, + // and that's unwise from separation-of-concerns perspective. + // + unparser.unparse1(state) + } + + /** + * Unparses the separator only. + * + * Does not deals with infix boundary condition, because + * the counting of the potential trailing separators takes + * this into account. + */ + private def unparseJustSeparator(state: UState): Unit = { + sep.unparse1(state) + } + + /** + * Returns 1, or 0 if infix separator, and this is the first thing + * in the sequence meaning there is no separator for it. + * + * However, if we're not doing trailing separator suppression, always + * returns 0. + */ + private def suppressedTrailingSeparatorIncrement(unparser: SequenceChildUnparser with Separated, state: UState): Int = { + Assert.usage(unparser.trd.isRepresented) + val notIPT = !unparser.ssAlgorithm.isInstanceOf[IPT] Review comment: Note that all this could be pre-computed at compile time except the groupPos check. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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