CBOR: fix default instance writing and verifying tags

Kotlin · Jul 2, 2024 · f4b43e7 · f4b43e7
1 parent 3d8768c
commit f4b43e7
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Showing 4 changed files with 267 additions and 36 deletions.
diff --git a/docs/formats.md b/docs/formats.md
@@ -250,7 +250,9 @@ When serializing, `ObjectTags` will always be encoded directly before to the dat
 value-tagged property of an object-tagged type will have the value tags preceding the object tags.
 Writing and verifying object tags can be toggled using the `writeObjectTags` and `verifyObjectTags` configuration
 switches. Note that verifying only value tags can result in some data with superfluous tags to still deserialize
-successfully, since in this case - by definition - only a partial validation of tags happens.
+successfully, since in this case - by definition - only a partial validation of tags happens.  
+A predefined Cbor instance (in addition to the default [`Cbor.Default`](Cbor.kt) one) is available, writing and verifying
+all tags as [`Cbor.Tagged`](Cbor.kt).
 
 In addition, CBOR supports keys of all types which work just as `SerialName`s.
 COSE restricts this again to strings and numbers and calls these restricted map keys *labels*. String labels can be

diff --git a/formats/cbor/commonMain/src/kotlinx/serialization/cbor/Cbor.kt b/formats/cbor/commonMain/src/kotlinx/serialization/cbor/Cbor.kt
@@ -57,10 +57,30 @@ public sealed class Cbor(
 ) : BinaryFormat {
 
     /**
-     * The default instance of [Cbor]
+     * The default instance of [Cbor]. Neither writes nor verifies tags. Uses indefinite length encoding by default.
      */
-    public companion object Default :
-        Cbor(false, false, true, true, true, true, true, false, false, true, false, EmptySerializersModule())
+    public companion object Default:
+        Cbor(false, false, false, false, false, false, false, false, false, false, false, EmptySerializersModule()) {
+
+        /**
+         * Stricter instance of [Cbor]. Writes and verifies all tags. Uses indefinite length encoding by default.
+         */
+        public val Tagging: Cbor =
+            Cbor {
+                encodeDefaults = false
+                ignoreUnknownKeys = false
+                writeKeyTags = true
+                writeValueTags = true
+                writeObjectTags = true
+                verifyKeyTags = true
+                verifyValueTags = true
+                verifyObjectTags = true
+                writeDefiniteLengths = false
+                preferCborLabelsOverNames = false
+                alwaysUseByteString = false
+                serializersModule = EmptySerializersModule()
+            }
+    }
 
     override fun <T> encodeToByteArray(serializer: SerializationStrategy<T>, value: T): ByteArray {
         val output = ByteArrayOutput()
@@ -89,7 +109,7 @@ private class CborImpl(
     writeObjectTags: Boolean,
     verifyKeyTags: Boolean,
     verifyValueTags: Boolean,
-    verifyObjectAndArrayTags: Boolean,
+    verifyObjectTags: Boolean,
     writeDefiniteLengths: Boolean,
     preferCborLabelsOverNames: Boolean,
     alwaysUseByteString: Boolean,
@@ -103,7 +123,7 @@ private class CborImpl(
         writeObjectTags,
         verifyKeyTags,
         verifyValueTags,
-        verifyObjectAndArrayTags,
+        verifyObjectTags,
         writeDefiniteLengths,
         preferCborLabelsOverNames,
         alwaysUseByteString,

diff --git a/formats/cbor/commonTest/src/kotlinx/serialization/cbor/CborArrayTest.kt b/formats/cbor/commonTest/src/kotlinx/serialization/cbor/CborArrayTest.kt
@@ -15,7 +15,7 @@ class CborArrayTest {
         val referenceHexString = "8126"
         val reference = ClassAs1Array(alg = -7)
 
-        val cbor = Cbor {
+        val cbor = Cbor(from = Cbor.Tagging) {
             writeDefiniteLengths = true
         }
         assertEquals(referenceHexString, cbor.encodeToHexString(ClassAs1Array.serializer(), reference))
@@ -34,7 +34,7 @@ class CborArrayTest {
         val referenceHexString = "c8822663666f6f"
         val reference = ClassAs2Array(alg = -7, kid = "foo")
 
-        val cbor = Cbor {
+        val cbor = Cbor(from = Cbor.Tagging) {
             writeDefiniteLengths = true
         }
         assertEquals(referenceHexString, cbor.encodeToHexString(ClassAs2Array.serializer(), reference))
@@ -54,7 +54,7 @@ class CborArrayTest {
         val referenceHexString = "842663626172f6a0"
         val reference = ClassAs4ArrayNullable(alg = -7, kid = "bar", iv = null, array = null)
 
-        val cbor = Cbor {
+        val cbor = Cbor(from = Cbor.Tagging) {
             writeDefiniteLengths = true
         }
 
@@ -77,7 +77,7 @@ class CborArrayTest {
         val referenceHexString = "a1656172726179c8822663626172"
         val reference = ClassWithArray(array = ClassAs2Array(alg = -7, kid = "bar"))
 
-        val cbor = Cbor {
+        val cbor = Cbor(from = Cbor.Tagging) {
             writeDefiniteLengths = true
         }
         assertEquals(referenceHexString, cbor.encodeToHexString(ClassWithArray.serializer(), reference))
@@ -103,7 +103,7 @@ class CborArrayTest {
         val referenceHexString = "a1656172726179c9c8822663626172"
         val reference = DoubleTaggedClassWithArray(array = ClassAs2Array(alg = -7, kid = "bar"))
 
-        val cbor = Cbor {
+        val cbor = Cbor(from = Cbor.Tagging) {
             writeDefiniteLengths = true
         }
         assertEquals(referenceHexString, cbor.encodeToHexString(DoubleTaggedClassWithArray.serializer(), reference))