[klib] Return the block's return value in inFile methods

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrFakeOverrideStrategy.kt

@@ -81,7 +81,6 @@ internal class Fir2IrFakeOverrideStrategy(
         }
     }
 
-    override fun inFile(file: IrFile?, block: () -> Unit) {
+    override fun <R> inFile(file: IrFile?, block: () -> R): R =
         publicIdSignatureComputer.inFile(file?.symbol, block)
-    }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/overrides/FakeOverrideBuilderStrategy.kt

@@ -71,7 +71,7 @@ abstract class FakeOverrideBuilderStrategy(
      * Contract:
      *  * must call [block] exactly once.
      */
-    abstract fun inFile(file: IrFile?, block: () -> Unit)
+    abstract fun <R> inFile(file: IrFile?, block: () -> R): R
 
     /**
      * Callback for creating a symbol for fake override function.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -1305,7 +1305,7 @@ private object BindToNewEmptySymbols : FakeOverrideBuilderStrategy(
         }
     }
 
-    override fun inFile(file: IrFile?, block: () -> Unit) { block() }
+    override fun <R> inFile(file: IrFile?, block: () -> R): R = block()
 }
 
 fun IrClass.addFakeOverrides(

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/overrides/FakeOverrides.kt

@@ -87,9 +87,8 @@ private class IrLinkerFakeOverrideBuilderStrategy(
     unimplementedOverridesStrategy = unimplementedOverridesStrategy
 ) {
 
-    override fun inFile(file: IrFile?, block: () -> Unit) {
+    override fun <R> inFile(file: IrFile?, block: () -> R): R =
         fakeOverrideDeclarationTable.inFile(file, block)
-    }
 
     override fun linkFunctionFakeOverride(function: IrFunctionWithLateBinding, manglerCompatibleMode: Boolean) {
         val (signature, symbol) = computeFunctionFakeOverrideSymbol(function, manglerCompatibleMode)

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/DeclarationTable.kt

@@ -46,10 +46,8 @@ open class DeclarationTable(globalTable: GlobalDeclarationTable) {
     // TODO: we need to disentangle signature construction with declaration tables.
     open val signaturer: IdSignatureFactory = IdSignatureFactory(globalTable.publicIdSignatureComputer, this)
 
-    fun inFile(file: IrFile?, block: () -> Unit) {
+    fun <R> inFile(file: IrFile?, block: () -> R): R =
         signaturer.inFile(file?.symbol, block)
-    }
-
 
     private fun IrDeclaration.isLocalDeclaration(compatibleMode: Boolean): Boolean {
         return !isExportedDeclaration(this, compatibleMode)

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrFileSerializer.kt

@@ -1326,17 +1326,7 @@ open class IrFileSerializer(
         }
     }
 
-    fun serializeIrFile(file: IrFile): SerializedIrFile {
-        var result: SerializedIrFile? = null
-
-        declarationTable.inFile(file) {
-            result = serializeIrFileImpl(file)
-        }
-
-        return result!!
-    }
-
-    private fun serializeIrFileImpl(file: IrFile): SerializedIrFile {
+    fun serializeIrFile(file: IrFile): SerializedIrFile = declarationTable.inFile(file) {
         val topLevelDeclarations = mutableListOf<SerializedDeclaration>()
 
         val proto = ProtoFile.newBuilder()
@@ -1379,7 +1369,7 @@ open class IrFileSerializer(
 
         fillPlatformExplicitlyExported(file, proto)
 
-        return SerializedIrFile(
+        SerializedIrFile(
             fileData = proto.build().toByteArray(),
             fqName = file.packageFqName.asString(),
             path = file.path,

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/signature/IdSignatureComputer.kt

@@ -36,7 +36,7 @@ interface IdSignatureComputer {
      * @param block A block within which signatures computed for private declarations will include [file]'s signature.
      * @see [IdSignature.FileSignature]
      */
-    fun inFile(file: IrFileSymbol?, block: () -> Unit)
+    fun <R> inFile(file: IrFileSymbol?, block: () -> R): R
 }
 
 class DescToIrIdSignatureComputer(private val delegate: IdSignatureDescriptor) : IdSignatureComputer {
@@ -49,7 +49,5 @@ class DescToIrIdSignatureComputer(private val delegate: IdSignatureDescriptor) :
         }
     }
 
-    override fun inFile(file: IrFileSymbol?, block: () -> Unit) {
-        block()
-    }
+    override fun <R> inFile(file: IrFileSymbol?, block: () -> R): R = block()
 }

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/signature/IdSignatureFactory.kt

@@ -39,12 +39,13 @@ class PublicIdSignatureComputer(val mangler: KotlinMangler.IrMangler) : IdSignat
 
     private var currentFileSignatureX: IdSignature.FileSignature? = null
 
-    override fun inFile(file: IrFileSymbol?, block: () -> Unit) {
+    override fun <R> inFile(file: IrFileSymbol?, block: () -> R): R {
         currentFileSignatureX = file?.let { IdSignature.FileSignature(it) }
-
-        block()
-
-        currentFileSignatureX = null
+        try {
+            return block()
+        } finally {
+            currentFileSignatureX = null
+        }
     }
 
     private fun IrDeclaration.checkIfPlatformSpecificExport(): Boolean = mangler.run { isPlatformSpecificExport() }
@@ -211,9 +212,8 @@ class IdSignatureFactory(
     private var localIndex: Long = startIndex.toLong()
     private var scopeIndex: Int = startIndex
 
-    override fun inFile(file: IrFileSymbol?, block: () -> Unit) {
+    override fun <R> inFile(file: IrFileSymbol?, block: () -> R): R =
         publicSignatureBuilder.inFile(file, block)
-    }
 
     private fun composeContainerIdSignature(container: IrDeclarationParent, compatibleMode: Boolean): IdSignature =
         when (container) {