Support AAB file format

Il2CppInspector.Common/FileFormatReaders/AABReader.cs

@@ -0,0 +1,73 @@
+/*
+    Copyright 2020 Katy Coe - http://www.djkaty.com - https://github.com/djkaty
+
+    All rights reserved.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+
+namespace Il2CppInspector
+{
+    // This is a wrapper for multiple binary files of different architectures within a single AAB
+    internal class AABReader : FileFormatReader<AABReader>
+    {
+        private ZipArchive zip;
+        private ZipArchiveEntry[] binaryFiles;
+
+        public AABReader(Stream stream) : base(stream) { }
+
+        protected override bool Init() {
+
+            // Check if it's a zip file first because ZipFile.OpenRead is extremely slow if it isn't
+            // 0x04034B50 = magic file header
+            // 0x02014B50 = central directory file header (will appear if we merged a split AAB in memory)
+            var magic = ReadUInt32();
+            if (magic != 0x04034B50 && magic != 0x02014B50)
+                return false;
+
+            try {
+                zip = new ZipArchive(BaseStream);
+
+                // Get list of binary files
+                binaryFiles = zip.Entries.Where(f => f.FullName.StartsWith("base/lib/") && f.Name == "libil2cpp.so").ToArray();
+
+                // This package doesn't contain an IL2CPP binary
+                if (!binaryFiles.Any())
+                    return false;
+            }
+
+            // Not an archive
+            catch (InvalidDataException) {
+                return false;
+            }
+
+            NumImages = (uint) binaryFiles.Count();
+            return true;
+        }
+
+        public override IFileFormatReader this[uint index] {
+            get {
+                Console.WriteLine($"Extracting binary from {binaryFiles[index].FullName}");
+                IFileFormatReader loaded = null;
+
+                // ZipArchiveEntry does not support seeking so we have to close and re-open for each possible load format
+                var binary = binaryFiles[index].Open();
+                loaded = ElfReader32.Load(binary, OnStatusUpdate);
+                binary.Close();
+
+                if (loaded != null)
+                    return loaded;
+
+                binary = binaryFiles[index].Open();
+                loaded = ElfReader64.Load(binary, OnStatusUpdate);
+                binary.Close();
+
+                return loaded;
+            }
+        }
+    }
+}

Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs

@@ -393,6 +393,7 @@ namespace Il2CppInspector
                     }
 
                 MemoryStream metadataMemoryStream = null, binaryMemoryStream = null;
+                ZipArchiveEntry androidAAB = null;
                 ZipArchiveEntry ipaBinaryFolder = null;
                 var binaryFiles = new List<ZipArchiveEntry>();
 
@@ -412,6 +413,14 @@ namespace Il2CppInspector
                     var metadataFile = zip.Entries.FirstOrDefault(f => f.FullName == "assets/bin/Data/Managed/Metadata/global-metadata.dat");
                     binaryFiles.AddRange(zip.Entries.Where(f => f.FullName.StartsWith("lib/") && f.Name == "libil2cpp.so"));
 
+                    // Check for Android AAB
+                    androidAAB = zip.Entries.FirstOrDefault(f => f.FullName == "base/resources.pb");
+
+                    if (androidAAB != null) {
+                        metadataFile = zip.Entries.FirstOrDefault(f => f.FullName == "base/assets/bin/Data/Managed/Metadata/global-metadata.dat");
+                        binaryFiles.AddRange(zip.Entries.Where(f => f.FullName.StartsWith("base/lib/") && f.Name == "libil2cpp.so"));
+                    }
+
                     // Check for iOS IPA
                     ipaBinaryFolder = zip.Entries.FirstOrDefault(f => f.FullName.StartsWith("Payload/") && f.FullName.EndsWith(".app/") && f.FullName.Count(x => x == '/') == 2);
 
@@ -452,8 +461,8 @@ namespace Il2CppInspector
                     binaryMemoryStream.Position = 0;
                 }
 
-                // Single APKs may have one or more binaries, one per architecture
+                // AABs or single APKs may have one or more binaries, one per architecture
-                // We'll read the entire APK and load those via APKReader
+                // We'll read the entire AAB/APK and load those via AABReader/APKReader
                 else if (packageFiles.Count() == 1) {
                     binaryMemoryStream = new MemoryStream(File.ReadAllBytes(packageFiles.First()));
                 }