feat: add capability to filter from protobuf buffer

src/main/kotlin/app/revanced/patches/youtube/misc/litho/filter/fingerprints/ProtobufBufferFingerprint.kt

@@ -0,0 +1,25 @@
+package app.revanced.patches.youtube.misc.litho.filter.fingerprints
+
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+import org.jf.dexlib2.Opcode
+
+object ProtobufBufferFingerprint : MethodFingerprint(
+    opcodes = listOf(
+        Opcode.IGET_OBJECT, // References the field required below.
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        Opcode.IF_NEZ,
+        Opcode.CONST_4,
+        Opcode.GOTO,
+        Opcode.CHECK_CAST, // Casts the referenced field to a specific type that stores the protobuf buffer.
+        Opcode.INVOKE_VIRTUAL
+    )
+)

src/main/kotlin/app/revanced/patches/youtube/misc/litho/filter/patch/LithoFilterPatch.kt

@@ -17,6 +17,7 @@ import app.revanced.patches.youtube.misc.integrations.patch.IntegrationsPatch
 import app.revanced.patches.youtube.misc.litho.filter.annotation.LithoFilterCompatibility
 import app.revanced.patches.youtube.misc.litho.filter.fingerprints.ComponentContextParserFingerprint
 import app.revanced.patches.youtube.misc.litho.filter.fingerprints.EmptyComponentBuilderFingerprint
+import app.revanced.patches.youtube.misc.litho.filter.fingerprints.ProtobufBufferFingerprint
 import app.revanced.patches.youtube.misc.litho.filter.fingerprints.ReadComponentIdentifierFingerprint
 import org.jf.dexlib2.iface.instruction.Instruction
 import org.jf.dexlib2.iface.instruction.OneRegisterInstruction
@@ -32,7 +33,9 @@ class LithoFilterPatch : BytecodePatch(
 ) {
     override fun execute(context: BytecodeContext): PatchResult {
         ComponentContextParserFingerprint.result?.also {
-            arrayOf(EmptyComponentBuilderFingerprint, ReadComponentIdentifierFingerprint).forEach { fingerprint ->
+            arrayOf(
+                EmptyComponentBuilderFingerprint, ReadComponentIdentifierFingerprint, ProtobufBufferFingerprint
+            ).forEach { fingerprint ->
                 if (!fingerprint.resolve(context, it.mutableMethod, it.mutableClass))
                     return fingerprint.toErrorResult()
             }
@@ -45,26 +48,54 @@ class LithoFilterPatch : BytecodePatch(
                 val builderMethodDescriptor = instruction(builderMethodIndex).descriptor
                 val emptyComponentFieldDescriptor = instruction(emptyComponentFieldIndex).descriptor
                 // Register is overwritten right after it is used in this patch, therefore free to clobber.
-                val clobberedRegister = instruction(insertHookIndex - 1).twoRegisterA
+                val free = instruction<TwoRegisterInstruction>(insertHookIndex - 1).registerA
+                val free2 = instruction<OneRegisterInstruction>(insertHookIndex).registerA
 
                 @Suppress("UnnecessaryVariable")
                 // The register, this patch clobbers, is previously used for the StringBuilder,
                 // later on a new StringBuilder is instantiated on it.
-                val stringBuilderRegister = clobberedRegister
+                val stringBuilderRegister = free
 
-                val identifierRegister = instruction(ReadComponentIdentifierFingerprint.patternScanEndIndex).oneRegisterA
+                val identifierRegister =
+                    instruction<OneRegisterInstruction>(ReadComponentIdentifierFingerprint.patternScanEndIndex).registerA
+
+                // Parameter that holds a ref to a type with a field that ref the protobuf buffer object.
+                val protobufParameterNumber = 3
+
+                // Get the field that stores an protobuf buffer required below.
+                val protobufBufferRefTypeRefFieldDescriptor =
+                    instruction(ProtobufBufferFingerprint.patternScanStartIndex).descriptor
+                val protobufBufferRefTypeDescriptor =
+                    instruction(ProtobufBufferFingerprint.patternScanEndIndex - 1).descriptor
+                val protobufBufferFieldDescriptor = "$protobufBufferRefTypeDescriptor->b:Ljava/nio/ByteBuffer;"
 
                 addInstructions(
-                    insertHookIndex, // right after setting the component.pathBuilder field,
+                    insertHookIndex, // right after setting the component.pathBuilder field.
                     """
-                        invoke-static {v$stringBuilderRegister, v$identifierRegister}, Lapp/revanced/integrations/patches/LithoFilterPatch;->filter(Ljava/lang/StringBuilder;Ljava/lang/String;)Z
-                        move-result v$clobberedRegister
-                        if-eqz v$clobberedRegister, :not_an_ad
-                        move-object/from16 v$clobberedRegister, p1
-                        invoke-static {v$clobberedRegister}, $builderMethodDescriptor
-                        move-result-object v$clobberedRegister
-                        iget-object v$clobberedRegister, v$clobberedRegister, $emptyComponentFieldDescriptor
-                        return-object v$clobberedRegister
+                        # Get the protobuf buffer object.
+                        
+                        move-object/from16 v$free2, p$protobufParameterNumber
+                        iget-object v$free2, v$free2, $protobufBufferRefTypeRefFieldDescriptor
+                        check-cast v$free2, $protobufBufferRefTypeDescriptor
+                      
+                        # Register "free" now holds the protobuf buffer object
+                       
+                        iget-object v$free2, v$free2, $protobufBufferFieldDescriptor
+                        
+                        # Invoke the filter method.
+                      
+                        invoke-static { v$stringBuilderRegister, v$identifierRegister, v$free2 }, $FILTER_METHOD_DESCRIPTOR
+                        move-result v$free
+                       
+                        if-eqz v$free, :not_an_ad
+                       
+                        # If the filter method returned true, then return a replacement empty component.
+                        
+                        move-object/from16 v$free, p1
+                        invoke-static {v$free}, $builderMethodDescriptor
+                        move-result-object v$free
+                        iget-object v$free, v$free, $emptyComponentFieldDescriptor
+                        return-object v$free
                     """,
                     listOf(ExternalLabel("not_an_ad", instruction(insertHookIndex)))
                 )
@@ -75,16 +106,20 @@ class LithoFilterPatch : BytecodePatch(
     }
 
     private companion object {
+        private val MethodFingerprint.patternScanResult
+            get() = result!!.scanResult.patternScanResult!!
+
         val MethodFingerprint.patternScanEndIndex
-            get() = result!!.scanResult.patternScanResult!!.endIndex
+            get() = patternScanResult.endIndex
+
+        val MethodFingerprint.patternScanStartIndex
+            get() = patternScanResult.startIndex
 
         val Instruction.descriptor
             get() = (this as ReferenceInstruction).reference.toString()
 
-        val Instruction.oneRegisterA
-            get() = (this as OneRegisterInstruction).registerA
-
-        val Instruction.twoRegisterA
-            get() = (this as TwoRegisterInstruction).registerA
+        const val FILTER_METHOD_DESCRIPTOR =
+            "Lapp/revanced/integrations/patches/litho/LithoFilterPatch;" +
+                    "->filter(Ljava/lang/StringBuilder;Ljava/lang/String;Ljava/nio/ByteBuffer;)Z"
     }
 }