stevedlawrence commented on code in PR #901:
URL: https://github.com/apache/daffodil/pull/901#discussion_r1067177831
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daffodil-runtime2/src/main/scala/org/apache/daffodil/runtime2/generators/CodeGeneratorState.scala:
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@@ -58,38 +56,209 @@ class CodeGeneratorState(private val root: ElementBase) {
sb
}
+ // Returns a name for the given element's element resource descriptor
+ private def erdName(context: ElementBase): String = {
+ val sb = buildName(context, new StringBuilder) ++= "ERD"
+ val name = sb.toString
+ name
+ }
+
// Returns a name for the given element's C struct identifier
private def cStructName(context: ElementBase): String = {
val sb = buildName(context, new StringBuilder)
val name = sb.toString
name
}
- // Returns a name for the given element's element resource descriptor
- private def erdName(context: ElementBase): String = {
- val sb = buildName(context, new StringBuilder) ++= "ERD"
- val name = sb.toString
- name
+ // Returns the notation needed to access a C struct field. We make some
simplifying
+ // assumptions to make generating the field access easier:
+ // - the expression contains only a relative or absolute path, nothing else
(e.g.,
+ // the expression doesn't call any functions or perform any computation)
+ // - we can convert an absolute path to a rootElement()-> indirection
+ // - we can convert a relative path beginning with up dirs to a parents->
indirection
+ // - we can convert a relative path without any up dirs to an instance->
indirection
+ // - we can convert slashes in the path to dots in a C struct field access
notation
+ private def cStructFieldAccess(expr: String): String = {
+ // Strip any namespace prefixes from expr and the root element's local
name since
+ // C code uses only struct fields' names.
+ val rootName = root.namedQName.local
+ val exprPath = expr.replaceAll("/[^/:]+:", "/").stripPrefix(s"/$rootName")
+ val fieldAccess = if (exprPath.startsWith("/")) {
+ // Convert exprPath to a rootElement()-> indirection
+ val C = cStructName(root)
+ s"""(($C *)rootElement())->${exprPath.stripPrefix("/")}"""
+ } else if (exprPath.startsWith("../")) {
+ // Split exprPath into the up dirs and after the up dirs
+ val afterUpDirs = exprPath.split("\\.\\./").mkString
+ val upDirs = exprPath.stripSuffix(afterUpDirs)
+ // Count how many up dirs there are
+ val nUpDirs = upDirs.split('/').length
+ // Go up the stack that many times to get that struct's C type
+ val C = structs(nUpDirs).C
+ // Convert the up dirs to parents
+ val parents = upDirs.replaceAllLiterally("../",
"parent->").stripSuffix("->")
+ // Convert exprPath to a parents-> indirection
+ s"""(($C *)instance->_base.$parents)->$afterUpDirs"""
+ } else {
+ // Convert exprPath to an instance-> indirection
+ s"""instance->$exprPath"""
+ }
+ // Finally, convert the field access to C struct dot notation
+ val notation = fieldAccess.replace('/', '.')
+ notation
}
- // Returns true if the element has not been seen before (checking if a
- // map already contains the element, otherwise adding it to the map)
- def elementNotSeenYet(context: ElementBase): Boolean = {
- val key = cStructName(context)
- val alreadySeen = elementsAlreadySeen.contains(key)
- if (!alreadySeen)
- elementsAlreadySeen += (key -> context)
- !alreadySeen
+ // Returns the code needed to get the size of an array of elements, which
+ // may be either a constant (maxOccurs) or an expression (occursCount)
+ // which accesses a particular C struct field.
+ private def getOccursCount(e: ElementBase): String = {
+ val occursCount = e.occursCountKind match {
+ case OccursCountKind.Fixed =>
+ s""" UNUSED(instance);
+ | return ${e.maxOccurs};""".stripMargin
+ case OccursCountKind.Expression =>
+ // Extract expression from {...} in element's occursCount attribute
+ val xml = e.occursCountEv.toBriefXML()
Review Comment:
We could do something like make `occursCountExpr` public and then you could
just do `e.occursCountExpr.prettyExpr`.
The evaluateables are really a runtime1 specific thing, so making `fooExpr`
vals public when needed by runtime2 doesn't seem unreasonable to me.
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