fix: nullable signature members (#10)

This commit will allow "partial" signatures, basically we will be allowed to exclude members to match for the signature

src/main/kotlin/net/revanced/patcher/resolver/MethodResolver.kt

@@ -56,7 +56,7 @@ internal class MethodResolver(private val classList: List<ClassNode>, private va
     companion object {
         fun resolveMethod(classNode: ClassNode, signature: Signature): PatchData? {
             for (method in classNode.methods) {
-                val (r, sr) = cmp(method, signature, true)
+                val (r, sr) = cmp(method, signature)
                 if (!r || sr == null) continue
                 return PatchData(
                     classNode,
@@ -67,52 +67,55 @@ internal class MethodResolver(private val classList: List<ClassNode>, private va
             return null
         }
 
-        private fun cmp(method: MethodNode, signature: Signature, search: Boolean = false): Pair<Boolean, ScanResult?> {
-            val returns = Type.getReturnType(method.desc).convertObject()
-            if (signature.returns != returns) {
-                logger.debug {
-                    """
-                    Comparing sig ${signature.name}: invalid return type:
-                    expected ${signature.returns}},
-                    got $returns
-                """.trimIndent()
+        private fun cmp(method: MethodNode, signature: Signature): Pair<Boolean, ScanResult?> {
+            signature.returns?.let { _ ->
+                val methodReturns = Type.getReturnType(method.desc).convertObject()
+                if (signature.returns != methodReturns) {
+                    logger.debug {
+                        """
+                            Comparing sig ${signature.name}: invalid return type:
+                            expected ${signature.returns},
+                            got $methodReturns
+                        """.trimIndent()
+                    }
+                    return@cmp false to null
                 }
-                return false to null
             }
 
-            if (signature.accessors != method.access) {
-                logger.debug {
-                    """
-                    Comparing sig ${signature.name}: invalid accessors:
-                    expected ${signature.accessors}},
-                    got ${method.access}
-                """.trimIndent()
+            signature.accessors?.let { _ ->
+                if (signature.accessors != method.access) {
+                    logger.debug {
+                        """
+                            Comparing sig ${signature.name}: invalid accessors:
+                            expected ${signature.accessors},
+                            got ${method.access}
+                        """.trimIndent()
+                    }
+                    return@cmp false to null
                 }
-                return false to null
             }
 
-            val parameters = Type.getArgumentTypes(method.desc).convertObjects()
-            if (!signature.parameters.contentEquals(parameters)) {
-                logger.debug {
-                    """
-                    Comparing sig ${signature.name}: invalid parameter types:
-                    expected ${signature.parameters.joinToString()}},
-                    got ${parameters.joinToString()}
-                """.trimIndent()
+            signature.parameters?.let { _ ->
+                val parameters = Type.getArgumentTypes(method.desc).convertObjects()
+                if (!signature.parameters.contentEquals(parameters)) {
+                    logger.debug {
+                        """
+                            Comparing sig ${signature.name}: invalid parameter types:
+                            expected ${signature.parameters.joinToString()}},
+                            got ${parameters.joinToString()}
+                        """.trimIndent()
+                    }
+                    return@cmp false to null
                 }
-                return false to null
             }
 
-            if (!search) {
-                if (signature.opcodes.isEmpty()) {
-                    throw IllegalArgumentException("Opcode list for signature ${signature.name} is empty. This is not allowed for non-search signatures.")
-                }
+            signature.opcodes?.let { _ ->
                 val result = method.instructions.scanFor(signature.opcodes)
                 if (!result.found) {
                     logger.debug { "Comparing sig ${signature.name}: invalid opcode pattern" }
-                    return false to null
+                    return@cmp false to null
                 }
-                return true to result
+                return@cmp true to result
             }
 
             return true to ScanResult(true)

src/main/kotlin/net/revanced/patcher/signature/Signature.kt

@@ -9,21 +9,19 @@ import org.objectweb.asm.Type
  * Do not use the actual method name, instead try to guess what the method name originally was.
  * If you are unable to guess a method name, doing something like "patch-name-1" is fine too.
  * For example: "override-codec-1".
- * This method name will be used to find the corresponding patch.
+ * This method name will be mapped to the method matching the signature.
  * Even though this is technically not needed for the `findParentMethod` method,
  * it is still recommended giving the method a name, so it can be identified easily.
  * @param returns The return type/signature of the method.
  * @param accessors The accessors of the method.
  * @param parameters The parameter types of the method.
  * @param opcodes The opcode pattern of the method, used to find the method by pattern scanning.
- * ***Only if*** **you are using **`findParentMethod`** are you allowed to specify an empty array.**
- * This parameter will be ignored when using the `findParentMethod` method.
  */
 @Suppress("ArrayInDataClass")
 data class Signature(
     val name: String,
-    val returns: Type,
-    val accessors: Int,
-    val parameters: Array<Type>,
-    val opcodes: Array<Int>
+    val returns: Type?,
+    val accessors: Int?,
+    val parameters: Array<Type>?,
+    val opcodes: Array<Int>?
 )

src/test/kotlin/net/revanced/patcher/PatcherTest.kt

@@ -9,13 +9,12 @@ import net.revanced.patcher.util.ExtraTypes
 import net.revanced.patcher.util.TestUtil
 import net.revanced.patcher.writer.ASMWriter.insertAt
 import net.revanced.patcher.writer.ASMWriter.setAt
-import org.junit.jupiter.api.assertThrows
+import org.junit.jupiter.api.assertDoesNotThrow
 import org.objectweb.asm.Opcodes.*
 import org.objectweb.asm.Type
 import org.objectweb.asm.tree.*
 import java.io.PrintStream
 import kotlin.test.Test
-import kotlin.test.assertEquals
 
 internal class PatcherTest {
     companion object {
@@ -149,25 +148,21 @@ internal class PatcherTest {
     //}
 
     @Test()
-    fun `should raise an exception because opcodes is empty`() {
+    fun `should not raise an exception if any signature member except the name is missing`() {
         val sigName = "testMethod"
-        val e = assertThrows<IllegalArgumentException>("Should raise an exception because opcodes is empty") {
+
+        assertDoesNotThrow("Should raise an exception because opcodes is empty") {
             Patcher(
                 PatcherTest::class.java.getResourceAsStream("/test1.jar")!!,
                 arrayOf(
                     Signature(
                         sigName,
-                        Type.VOID_TYPE,
-                        ACC_PUBLIC or ACC_STATIC,
-                        arrayOf(ExtraTypes.ArrayAny),
-                        emptyArray() // this is not allowed for non-search signatures!
-                    )
-                )
+                        null,
+                        null,
+                        null,
+                        null
+                    ))
             )
         }
-        assertEquals(
-            "Opcode list for signature $sigName is empty. This is not allowed for non-search signatures.",
-            e.message
-        )
     }
 }