Add a build/write-prefetch unparse path driven by a dedicated Builder tree

.github/workflows/main.yml

@@ -197,6 +197,14 @@ jobs:
       - name: Run Unit Tests
         run: $SBT test
 
+      # Build ahead is the default, so run the suite once more event driven to
+      # keep that unparse path tested.
+      - name: Run Unit Tests (event-driven unparse)
+        if: matrix.os == 'ubuntu-22.04' && matrix.java_version == '17'
+        env:
+          DAFFODIL_TDML_TUNABLES: infosetBuilderMode=eventDriven
+        run: $SBT test
+
       - name: Run Integration Tests
         run: $SBT daffodil-test-integration/test
 

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/Grammar.scala

@@ -21,6 +21,8 @@ import org.apache.daffodil.core.compiler.ForParser
 import org.apache.daffodil.core.compiler.ForUnparser
 import org.apache.daffodil.core.dsom.*
 import org.apache.daffodil.lib.exceptions.Assert
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.SeqCompInfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.AssertExpressionEvaluationParser
 import org.apache.daffodil.runtime1.processors.parsers.NadaParser
 import org.apache.daffodil.runtime1.processors.parsers.SeqCompParser
@@ -124,6 +126,19 @@ class SeqComp private (context: SchemaComponent, children: Seq[Gram])
     else if (unparserChildren.length == 1) unparserChildren.head
     else new SeqCompUnparser(context.runtimeData, unparserChildren.toArray)
   }
+
+  // Only the (usually at most one) child(ren) that actually build infoset
+  // content contribute here; children that build no infoset events
+  // (delimiters, padding, etc.) simply have no builder to collect.
+  lazy val builderChildren: Array[InfosetBuilder] = {
+    children
+      .filter(x => !x.isEmpty && (x.forWhat != ForParser))
+      .map(_.builder)
+      .filterNot(_.isEmpty)
+      .toArray
+  }
+
+  final override lazy val builder: InfosetBuilder = SeqCompInfosetBuilder(builderChildren)
 }
 
 object EmptyGram extends Gram(null) {

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/Production.scala

@@ -22,6 +22,8 @@ import org.apache.daffodil.core.compiler.ForUnparser
 import org.apache.daffodil.core.compiler.ParserOrUnparser
 import org.apache.daffodil.core.dsom.SchemaComponent
 import org.apache.daffodil.lib.util.Logger
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.NadaInfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.NadaParser
 import org.apache.daffodil.unparsers.runtime1.NadaUnparser
 
@@ -107,4 +109,16 @@ final class Prod(
     else
       unp
   }
+
+  final override lazy val builder: InfosetBuilder = {
+    if (gram.isEmpty) {
+      NadaInfosetBuilder
+    } else {
+      (forWhat, gram.forWhat) match {
+        case (ForParser, _) => NadaInfosetBuilder
+        case (_, ForParser) => NadaInfosetBuilder
+        case _ => gram.builder
+      }
+    }
+  }
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/ChoiceCombinator.scala

@@ -29,10 +29,17 @@ import org.apache.daffodil.lib.cookers.ChoiceBranchKeyCooker
 import org.apache.daffodil.lib.cookers.IntRangeCooker
 import org.apache.daffodil.lib.exceptions.Assert
 import org.apache.daffodil.lib.schema.annotation.props.gen.ChoiceLengthKind
+import org.apache.daffodil.lib.util.Maybe
+import org.apache.daffodil.lib.util.Maybe.Nope
+import org.apache.daffodil.lib.util.Maybe.One
 import org.apache.daffodil.lib.util.MaybeInt
 import org.apache.daffodil.lib.util.ProperlySerializableMap.*
 import org.apache.daffodil.lib.xml.NamedQName
+import org.apache.daffodil.runtime1.infoset.ChoiceInfosetBuilder
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.NadaInfosetBuilder
 import org.apache.daffodil.runtime1.processors.RangeBound
+import org.apache.daffodil.runtime1.processors.TermRuntimeData
 import org.apache.daffodil.runtime1.processors.parsers.*
 import org.apache.daffodil.runtime1.processors.unparsers.*
 import org.apache.daffodil.unparsers.runtime1.*
@@ -266,8 +273,15 @@ case class ChoiceCombinator(ch: ChoiceTermBase, alternatives: Seq[Gram])
     }
   }
 
+  private lazy val eventUnparserMap = ch.choiceBranchMap._1.map { case (qname, branchTerm) =>
+    (qname, branchTerm.termContentBody.unparser)
+  }
+
+  private lazy val hasEventBranchUnparser: Boolean =
+    eventUnparserMap.exists { case (_, branchUnparser) => !branchUnparser.isEmpty }
+
   override lazy val unparser: Unparser = {
-    val (eventRDMap, optDefaultBranch) = ch.choiceBranchMap
+    val optDefaultBranch = ch.choiceBranchMap._2
     /*
      * Since it's impossible to know the hiddenness for terms at this level (unless
      * they're a hiddenGroupRef), we always attempt to find a defaultable unparser.
@@ -313,11 +327,7 @@ case class ChoiceCombinator(ch: ChoiceTermBase, alternatives: Seq[Gram])
       optDefaultUnparser
     }
 
-    val eventUnparserMap = eventRDMap.map { case (qname, branchTerm) =>
-      (qname, branchTerm.termContentBody.unparser)
-    }
-    val mapValues = eventUnparserMap.map { case (k, v) => v }.filterNot(_.isEmpty)
-    if (mapValues.isEmpty) {
+    if (!hasEventBranchUnparser) {
       if (branchForUnparse.isEmpty) {
         new NadaUnparser(null)
       } else {
@@ -332,4 +342,22 @@ case class ChoiceCombinator(ch: ChoiceTermBase, alternatives: Seq[Gram])
       new ChoiceCombinatorUnparser(ch.modelGroupRuntimeData, cbm, choiceLengthInBits)
     }
   }
+
+  override lazy val builder: InfosetBuilder = {
+    val (eventRDMap, optDefaultBranch) = ch.choiceBranchMap
+
+    if (!hasEventBranchUnparser && optDefaultBranch.isEmpty) {
+      NadaInfosetBuilder
+    } else {
+      val branchMap: Map[NamedQName, (TermRuntimeData, InfosetBuilder)] =
+        eventRDMap.map { case (qname, branchTerm) =>
+          (qname, (branchTerm.termRuntimeData, branchTerm.termContentBody.builder))
+        }
+      val defaultBranch: Maybe[(TermRuntimeData, InfosetBuilder)] = optDefaultBranch match {
+        case Some(term) => One((term.termRuntimeData, term.termContentBody.builder))
+        case None => Nope
+      }
+      new ChoiceInfosetBuilder(ch.modelGroupRuntimeData, branchMap, defaultBranch)
+    }
+  }
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/DelimiterAndEscapeRelated.scala

@@ -21,9 +21,11 @@ import org.apache.daffodil.core.dsom.*
 import org.apache.daffodil.core.grammar.Gram
 import org.apache.daffodil.core.grammar.Terminal
 import org.apache.daffodil.lib.exceptions.Assert
+import org.apache.daffodil.lib.util.Maybe
 import org.apache.daffodil.lib.util.Maybe.*
 import org.apache.daffodil.lib.util.Misc
 import org.apache.daffodil.lib.xml.XMLUtils
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.{ Parser as DaffodilParser, * }
 import org.apache.daffodil.runtime1.processors.unparsers.Unparser as DaffodilUnparser
 import org.apache.daffodil.unparsers.runtime1.*
@@ -55,6 +57,10 @@ case class DelimiterStackCombinatorSequence(sq: SequenceTermBase, body: Gram)
 
   override lazy val unparser: DaffodilUnparser =
     new DelimiterStackUnparser(uInit, uSep, uTerm, sq.termRuntimeData, body.unparser)
+
+  // Delimiters build no infoset events; the builder tree skips straight to
+  // whatever this sequence's body itself builds, if anything.
+  override lazy val builder: InfosetBuilder = body.builder
 }
 
 case class DelimiterStackCombinatorChoice(ch: ChoiceTermBase, body: Gram)
@@ -77,6 +83,10 @@ case class DelimiterStackCombinatorChoice(ch: ChoiceTermBase, body: Gram)
 
   override lazy val unparser: DaffodilUnparser =
     new DelimiterStackUnparser(uInit, None, uTerm, ch.termRuntimeData, body.unparser)
+
+  // Delimiters build no infoset events; the builder tree skips straight to
+  // whatever this choice's body itself builds, if anything.
+  override lazy val builder: InfosetBuilder = body.builder
 }
 
 case class DelimiterStackCombinatorElement(e: ElementBase, body: Gram)
@@ -111,6 +121,10 @@ case class DelimiterStackCombinatorElement(e: ElementBase, body: Gram)
     if (u.isEmpty) u
     else new DelimiterStackUnparser(uInit, None, uTerm, e.termRuntimeData, u)
   }
+
+  // Delimiters build no infoset events; the builder tree skips straight to
+  // whatever this element's body itself builds, if anything.
+  override lazy val builder: InfosetBuilder = body.builder
 }
 
 case class DynamicEscapeSchemeCombinatorElement(e: ElementBase, body: Gram)
@@ -135,4 +149,9 @@ case class DynamicEscapeSchemeCombinatorElement(e: ElementBase, body: Gram)
     if (u.isEmpty || schemeUnparseIsConstant) u
     else new DynamicEscapeSchemeUnparser(schemeUnparseOpt.get, e.termRuntimeData, u)
   }
+
+  // The escape scheme only governs delimiter matching in written bytes; the
+  // builder tree skips straight to whatever this element's body itself
+  // builds, if anything.
+  override lazy val builder: InfosetBuilder = body.builder
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/ElementCombinator.scala

@@ -28,6 +28,9 @@ import org.apache.daffodil.lib.schema.annotation.props.gen.LengthKind
 import org.apache.daffodil.lib.schema.annotation.props.gen.Representation
 import org.apache.daffodil.lib.schema.annotation.props.gen.TestKind
 import org.apache.daffodil.lib.util.Maybe
+import org.apache.daffodil.runtime1.infoset.ElementInfosetBuilder
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.NadaInfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.CaptureEndOfContentLengthParser
 import org.apache.daffodil.runtime1.processors.parsers.CaptureEndOfValueLengthParser
 import org.apache.daffodil.runtime1.processors.parsers.CaptureStartOfContentLengthParser
@@ -44,6 +47,7 @@ import org.apache.daffodil.unparsers.runtime1.CaptureStartOfValueLengthUnparser
 import org.apache.daffodil.unparsers.runtime1.ElementOVCSpecifiedLengthUnparser
 import org.apache.daffodil.unparsers.runtime1.ElementOVCUnspecifiedLengthUnparser
 import org.apache.daffodil.unparsers.runtime1.ElementSpecifiedLengthUnparser
+import org.apache.daffodil.unparsers.runtime1.ElementUnparserBase
 import org.apache.daffodil.unparsers.runtime1.ElementUnparserInputValueCalc
 import org.apache.daffodil.unparsers.runtime1.ElementUnspecifiedLengthUnparser
 import org.apache.daffodil.unparsers.runtime1.ElementUnusedUnparser
@@ -111,6 +115,12 @@ class ElementCombinator(
 
   private lazy val eRepTypeUnparser: Maybe[Unparser] = repTypeElementGram.maybeUnparser
 
+  private lazy val isSpecifiedLength: Boolean =
+    (context.lengthKind._eq_(LengthKind.Explicit)) ||
+      (context.isSimpleType &&
+        (context.lengthKind._eq_(LengthKind.Implicit)) &&
+        (context.impliedRepresentation._eq_(Representation.Text)))
+
   override lazy val unparser: Unparser = {
     if (context.isOutputValueCalc) {
       new ElementOVCSpecifiedLengthUnparser(
@@ -122,12 +132,7 @@ class ElementCombinator(
         eAfterUnparser,
         context.ovcCompiledExpression
       )
-    } else if (
-      (context.lengthKind._eq_(LengthKind.Explicit)) ||
-      (context.isSimpleType &&
-        (context.lengthKind._eq_(LengthKind.Implicit)) &&
-        (context.impliedRepresentation._eq_(Representation.Text)))
-    ) {
+    } else if (isSpecifiedLength) {
 
       new ElementSpecifiedLengthUnparser(
         context.erd,
@@ -143,6 +148,26 @@ class ElementCombinator(
     }
   }
 
+  private lazy val eBuilder: InfosetBuilder = {
+    if (eValue.isEmpty) {
+      NadaInfosetBuilder
+    } else {
+      eValue.builder
+    }
+  }
+  private lazy val eRepTypeBuilder: InfosetBuilder = repTypeElementGram.builder
+
+  // Shares the memoized unparser above for unparseBegin/unparseEnd, so
+  // build and the unparse see identical node-creation behavior.
+  override lazy val builder: InfosetBuilder = {
+    if (context.isOutputValueCalc || isSpecifiedLength) {
+      val eu = unparser.asInstanceOf[ElementUnparserBase]
+      val contentBuilder = eRepTypeBuilder.orElse(eBuilder)
+      new ElementInfosetBuilder(context.erd, eu, contentBuilder)
+    } else {
+      subComb.builder
+    }
+  }
 }
 
 case class ElementUnused(ctxt: ElementBase)
@@ -374,6 +399,14 @@ class ElementParseAndUnspecifiedLength(
       new ElementUnparserInputValueCalc(context.erd, uSetVar)
     }
   }
+
+  // Shares the memoized unparser above for unparseBegin/unparseEnd, so
+  // build and the unparse see identical nilled/OVC/IVC node-creation behavior.
+  override lazy val builder: InfosetBuilder = {
+    val eu = unparser.asInstanceOf[ElementUnparserBase]
+    val contentBuilder = eRepTypeBuilder.orElse(eBuilder)
+    new ElementInfosetBuilder(context.erd, eu, contentBuilder)
+  }
 }
 
 abstract class ElementCombinatorBase(
@@ -449,4 +482,8 @@ abstract class ElementCombinatorBase(
 
   def unparser: Unparser
 
+  lazy val eBuilder: InfosetBuilder = eGram.builder
+
+  lazy val eRepTypeBuilder: InfosetBuilder = repTypeElementGram.builder
+
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/HiddenGroupCombinator.scala

@@ -20,6 +20,8 @@ package org.apache.daffodil.core.grammar.primitives
 import org.apache.daffodil.core.dsom.ModelGroup
 import org.apache.daffodil.core.grammar.Gram
 import org.apache.daffodil.core.grammar.Terminal
+import org.apache.daffodil.runtime1.infoset.HiddenGroupInfosetBuilder
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.HiddenGroupCombinatorParser
 import org.apache.daffodil.runtime1.processors.parsers.Parser
 import org.apache.daffodil.runtime1.processors.unparsers.Unparser
@@ -34,4 +36,5 @@ final class HiddenGroupCombinator(ctxt: ModelGroup, body: Gram)
   override lazy val unparser: Unparser =
     new HiddenGroupCombinatorUnparser(ctxt.modelGroupRuntimeData, body.unparser)
 
+  override lazy val builder: InfosetBuilder = HiddenGroupInfosetBuilder(body.builder)
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/LayeredSequence.scala

@@ -21,6 +21,8 @@ import org.apache.daffodil.core.dsom.*
 import org.apache.daffodil.core.grammar.Terminal
 import org.apache.daffodil.core.layers.LayerSchemaCompiler
 import org.apache.daffodil.lib.util.Misc
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.SequenceInfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.LayeredSequenceParser
 import org.apache.daffodil.runtime1.processors.parsers.Parser as DaffodilParser
 import org.apache.daffodil.runtime1.processors.unparsers.Unparser as DaffodilUnparser
@@ -47,4 +49,11 @@ case class LayeredSequence(sq: SequenceGroupTermBase, bodyTerm: SequenceChild)
 
   override lazy val unparser: DaffodilUnparser =
     new LayeredSequenceUnparser(srd, bodyUnparser)
+
+  // The layer transform builds no infoset events, but this is still a one-child
+  // sequence position: it must push/pop bodyTerm's TRD and advance the
+  // group index like any sequence child, or next-element resolution on
+  // the shared InfosetInputter breaks.
+  override lazy val builder: InfosetBuilder =
+    SequenceInfosetBuilder(Array(bodyTerm.sequenceChildBuildInfo))
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/NilEmptyCombinators.scala

@@ -21,6 +21,8 @@ import org.apache.daffodil.core.dsom.ElementBase
 import org.apache.daffodil.core.grammar.Gram
 import org.apache.daffodil.core.grammar.Terminal
 import org.apache.daffodil.lib.exceptions.Assert
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.NilOrContentInfosetBuilder
 import org.apache.daffodil.runtime1.processors.parsers.ComplexNilOrContentParser
 import org.apache.daffodil.runtime1.processors.parsers.SimpleNilOrValueParser
 import org.apache.daffodil.unparsers.runtime1.ComplexNilOrContentUnparser
@@ -59,4 +61,8 @@ case class ComplexNilOrContent(ctxt: ElementBase, nilGram: Gram, contentGram: Gr
   override lazy val unparser =
     ComplexNilOrContentUnparser(ctxt.erd, nilUnparser, contentUnparser)
 
+  // A nilled complex element has no children to build; nilled-ness is only
+  // known once the node exists, so this needs a real runtime check, not a
+  // static pass-through.
+  override lazy val builder: InfosetBuilder = NilOrContentInfosetBuilder(contentGram.builder)
 }

daffodil-core/src/main/scala/org/apache/daffodil/core/grammar/primitives/SequenceChild.scala

@@ -25,6 +25,8 @@ import org.apache.daffodil.lib.schema.annotation.props.gen.LengthKind
 import org.apache.daffodil.lib.schema.annotation.props.gen.OccursCountKind
 import org.apache.daffodil.lib.schema.annotation.props.gen.Representation
 import org.apache.daffodil.runtime1.dpath.NodeInfo
+import org.apache.daffodil.runtime1.infoset.InfosetBuilder
+import org.apache.daffodil.runtime1.infoset.SequenceChildInfosetBuildInfo
 import org.apache.daffodil.runtime1.processors.parsers.*
 import org.apache.daffodil.unparsers.runtime1.*
 
@@ -69,6 +71,7 @@ abstract class SequenceChild(protected val sq: SequenceTermBase, child: Term, gr
 
   protected lazy val childParser = child.termContentBody.parser
   protected lazy val childUnparser = child.termContentBody.unparser
+  protected lazy val childBuilder: InfosetBuilder = child.termContentBody.builder
 
   final override lazy val parser = sequenceChildParser
   final override lazy val unparser = sequenceChildUnparser
@@ -82,6 +85,9 @@ abstract class SequenceChild(protected val sq: SequenceTermBase, child: Term, gr
   final lazy val optSequenceChildUnparser: Option[SequenceChildUnparser] =
     if (childUnparser.isEmpty) None else Some(unparser)
 
+  final lazy val sequenceChildBuildInfo: SequenceChildInfosetBuildInfo =
+    SequenceChildInfosetBuildInfo(unparser, childBuilder)
+
   /**
    * There's only parse result helpers here, so let's abbreviate
    */