-
Notifications
You must be signed in to change notification settings - Fork 296
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Browse files
Browse the repository at this point in the history
This draft translates ruby `case` expressions into `if-elif-...-else-end` chains. The expression matched against is assigned a temporary variable `<tmp-#>` where # is a number. I was not sure on the convention but I wanted to be sure the variable is always fresh. A single when can contain a list of expressions to match against, which I translate into an `or-expression` if there is more than one. When matching against an expression `mExpr`, it is turned into a condition with `mExpr.=== <tmp-#>`. This list of expressions can contain a splat at the end, which we aren't handling yet. It also remains maybe to special case to a switch ast if all match expressions are literals. TextSpans for the generated intermediate ast are not sane and will need to be considered more carefully. --------- Co-authored-by: David Baker Effendi <[email protected]>
- Loading branch information
1 parent
438a1c9
commit 21558c7
Showing
8 changed files
with
202 additions
and
8 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
15 changes: 15 additions & 0 deletions
15
...ds/rubysrc2cpg/src/main/scala/io/joern/rubysrc2cpg/astcreation/FreshVariableCreator.scala
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,15 @@ | ||
| package io.joern.rubysrc2cpg.astcreation | ||
|
|
||
| import io.joern.rubysrc2cpg.astcreation.AstCreator | ||
| import io.joern.rubysrc2cpg.astcreation.RubyIntermediateAst.* | ||
|
|
||
| trait FreshVariableCreator { this: AstCreator => | ||
| // This is in a single-threaded context. | ||
| var tmpCounter: Int = 0 | ||
| private def tmpTemplate(id: Int): String = s"<tmp-${id}>" | ||
| protected def freshName: String = { | ||
| val name = tmpTemplate(tmpCounter) | ||
| tmpCounter += 1 | ||
| name | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
92 changes: 92 additions & 0 deletions
92
joern-cli/frontends/rubysrc2cpg/src/test/scala/io/joern/rubysrc2cpg/querying/CaseTests.scala
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,92 @@ | ||
| package io.joern.rubysrc2cpg.querying | ||
|
|
||
| import io.joern.rubysrc2cpg.testfixtures.RubyCode2CpgFixture | ||
| import io.shiftleft.semanticcpg.language.* | ||
| import io.shiftleft.codepropertygraph.generated.nodes.* | ||
| import io.shiftleft.codepropertygraph.generated.Operators | ||
|
|
||
| class CaseTests extends RubyCode2CpgFixture { | ||
| "`case x ... end` should be represented with if-else chain and multiple match expressions should be or-ed together" in { | ||
| val caseCode = """ | ||
| |case 0 | ||
| | when 0 | ||
| | 0 | ||
| | when 1,2 then 1 | ||
| | when 3, *[4,5] then 2 | ||
| | when *[6] then 3 | ||
| | else 4 | ||
| |end | ||
| |""".stripMargin | ||
| val cpg = code(caseCode) | ||
|
|
||
| val block @ List(_) = cpg.method(":program").block.astChildren.isBlock.l | ||
|
|
||
| val List(assign) = block.astChildren.assignment.l; | ||
| val List(lhs, rhs) = assign.argument.l | ||
|
|
||
| List(lhs).isCall.name.l shouldBe List("<tmp-0>") | ||
| List(rhs).isLiteral.code.l shouldBe List("0") | ||
|
|
||
| val headIf @ List(_) = block.astChildren.isControlStructure.l | ||
| val ifStmts @ List(_, _, _, _) = headIf.repeat(_.astChildren.order(3).astChildren.isControlStructure)(_.emit).l; | ||
| val conds: List[List[String]] = ifStmts.condition.map { cond => | ||
| val orConds = List(cond) | ||
| .repeat(_.isCall.where(_.name(Operators.logicalOr)).argument)( | ||
| _.emit(_.whereNot(_.isCall.name(Operators.logicalOr))) | ||
| ) | ||
| .l | ||
| orConds.map { | ||
| case u: Unknown => "unknown" | ||
| case mExpr => | ||
| val call @ List(_) = List(mExpr).isCall.l | ||
| call.methodFullName.l shouldBe List("===") | ||
| val List(lhs, rhs) = call.argument.l | ||
| rhs.code shouldBe "<tmp-0>" | ||
| val List(code) = List(lhs).isCall.argument(1).code.l | ||
| code | ||
| }.l | ||
| }.l | ||
|
|
||
| conds shouldBe List(List("0"), List("1", "2"), List("3", "unknown"), List("unknown")) | ||
| val matchResults = ifStmts.astChildren.order(2).astChildren ++ ifStmts.last.astChildren.order(3).astChildren | ||
| matchResults.code.l shouldBe List("0", "1", "2", "3", "4") | ||
|
|
||
| // It's not ideal, but we choose the smallest containing text span that we have easily acesssible | ||
| // as we don't have a good way to immutably update RubyNode text spans. | ||
| ifStmts.code.l should contain only caseCode.trim | ||
| ifStmts.condition.map(_.code.trim).l shouldBe List("0", "when 1,2 then 1", "when 3, *[4,5] then 2", "*[6]") | ||
| } | ||
|
|
||
| "`case ... end` without expression" in { | ||
| val cpg = code(""" | ||
| |case | ||
| | when false, true then 0 | ||
| | when true then 1 | ||
| | when false, *[false,false] then 2 | ||
| | when *[false, true] then 3 | ||
| |end | ||
| |""".stripMargin) | ||
|
|
||
| val block @ List(_) = cpg.method(":program").block.astChildren.isBlock.l | ||
|
|
||
| val headIf @ List(_) = block.astChildren.isControlStructure.l | ||
| val ifStmts @ List(_, _, _, _) = headIf.repeat(_.astChildren.order(3).astChildren.isControlStructure)(_.emit).l; | ||
| val conds: List[List[String]] = ifStmts.condition.map { cond => | ||
| val orConds = List(cond) | ||
| .repeat(_.isCall.where(_.name(Operators.logicalOr)).argument)( | ||
| _.emit(_.whereNot(_.isCall.name(Operators.logicalOr))) | ||
| ) | ||
| .l | ||
| orConds.map { | ||
| case u: Unknown => "unknown" | ||
| case c => c.code | ||
| } | ||
| }.l | ||
| conds shouldBe List(List("false", "true"), List("true"), List("false", "unknown"), List("unknown")) | ||
|
|
||
| val matchResults = ifStmts.astChildren.order(2).astChildren.l | ||
| matchResults.code.l shouldBe List("0", "1", "2", "3") | ||
|
|
||
| ifStmts.last.astChildren.order(3).l shouldBe List() | ||
| } | ||
| } |