Feat: Introduce "res-mode" options. (#3318)

* Revert "Remove Apktool Dummys. (#3258)"

This reverts commit 0e22692.

* feat: properly add dummys

* refactor: shorten ResTypeSpec

* style: remove extra space

* refactor: extract FlagItem into own class

* refactor: notate which type is null

* fix: only add dummys if enabled

* feat: skip unknown (if enabled)

* feat: introduce "res-mode"

* feat: expose config on res table

* feat: add method to base attr for res skips

* fix: ensure autobuild doesn't choke

* refactor: remove java17 enhanced switch

* refactor: rename methods

* refactor: cleanup res-mode param

* test: introduction of test/sample apk

* refactor: make ResXmlPatcher public for loading XML

* test: assertions for dummy|leave|retain

* fix: prevent using `@null` as a name

* refactor: shorten long param for 'resm'

* refactor: leave for preserve

brut.apktool/apktool-cli/src/main/java/brut/apktool/Main.java

@@ -167,6 +167,30 @@ private static void cmdDecode(CommandLine cli, Config config) throws AndrolibExc
         if (cli.hasOption("m") || cli.hasOption("match-original")) {
             config.analysisMode = true;
         }
+        if (cli.hasOption("res-mode") || cli.hasOption("resolve-resources-mode")) {
+            String mode = cli.getOptionValue("res-mode");
+            if (mode == null) {
+                mode = cli.getOptionValue("resolve-resources-mode");
+            }
+            switch (mode) {
+                case "remove":
+                case "delete":
+                    config.setDecodeResolveMode(Config.DECODE_RES_RESOLVE_REMOVE);
+                    break;
+                case "dummy":
+                case "dummies":
+                    config.setDecodeResolveMode(Config.DECODE_RES_RESOLVE_DUMMY);
+                    break;
+                case "keep":
+                case "preserve":
+                    config.setDecodeResolveMode(Config.DECODE_RES_RESOLVE_RETAIN);
+                    break;
+                default:
+                    System.err.println("Unknown resolve resources mode: " + mode);
+                    System.err.println("Expect: 'remove', 'dummy' or 'keep'.");
+                    System.exit(1);
+            }
+        }
 
         File outDir;
         if (cli.hasOption("o") || cli.hasOption("output")) {
@@ -301,8 +325,6 @@ private static void _version() {
     }
 
     private static void _Options() {
-
-        // create options
         Option versionOption = Option.builder("version")
                 .longOpt("version")
                 .desc("Print the version.")
@@ -409,6 +431,13 @@ private static void _Options() {
                 .desc("Skip changes detection and build all files.")
                 .build();
 
+        Option resolveResModeOption = Option.builder("resm")
+                .longOpt("resource-mode")
+                .desc("Sets the resolve resources mode. Possible values are: 'remove' (default), 'dummy' or 'keep'.")
+                .hasArg(true)
+                .argName("mode")
+                .build();
+
         Option aaptOption = Option.builder("a")
                 .longOpt("aapt")
                 .hasArg(true)
@@ -469,6 +498,7 @@ private static void _Options() {
             decodeOptions.addOption(apiLevelOption);
             decodeOptions.addOption(noAssetOption);
             decodeOptions.addOption(forceManOption);
+            decodeOptions.addOption(resolveResModeOption);
 
             buildOptions.addOption(apiLevelOption);
             buildOptions.addOption(debugBuiOption);
@@ -525,6 +555,7 @@ private static void _Options() {
         allOptions.addOption(debugDecOption);
         allOptions.addOption(noDbgOption);
         allOptions.addOption(forceManOption);
+        allOptions.addOption(resolveResModeOption);
         allOptions.addOption(noAssetOption);
         allOptions.addOption(keepResOption);
         allOptions.addOption(debugBuiOption);

brut.apktool/apktool-lib/src/main/java/brut/androlib/Config.java

@@ -23,6 +23,7 @@
 import java.util.logging.Logger;
 
 public class Config {
+    private static Config instance = null;
     private final static Logger LOGGER = Logger.getLogger(Config.class.getName());
 
     public final static short DECODE_SOURCES_NONE = 0x0000;
@@ -38,6 +39,10 @@ public class Config {
     public final static short DECODE_ASSETS_NONE = 0x0000;
     public final static short DECODE_ASSETS_FULL = 0x0001;
 
+    public final static short DECODE_RES_RESOLVE_REMOVE = 0x0000;
+    public final static short DECODE_RES_RESOLVE_DUMMY = 0x0001;
+    public final static short DECODE_RES_RESOLVE_RETAIN = 0x0002;
+
     // Build options
     public boolean forceBuildAll = false;
     public boolean forceDeleteFramework = false;
@@ -55,6 +60,7 @@ public class Config {
     public short decodeResources = DECODE_RESOURCES_FULL;
     public short forceDecodeManifest = FORCE_DECODE_MANIFEST_NONE;
     public short decodeAssets = DECODE_ASSETS_FULL;
+    public short decodeResolveMode = DECODE_RES_RESOLVE_REMOVE;
     public int apiLevel = 0;
     public boolean analysisMode = false;
     public boolean forceDelete = false;
@@ -72,8 +78,23 @@ public boolean isAapt2() {
         return this.useAapt2 || this.aaptVersion == 2;
     }
 
+    public boolean isDecodeResolveModeUsingDummies() {
+        return decodeResolveMode == DECODE_RES_RESOLVE_DUMMY;
+    }
+
+    public boolean isDecodeResolveModeRemoving() {
+        return decodeResolveMode == DECODE_RES_RESOLVE_REMOVE;
+    }
+
     private Config() {
+        instance = this;
+    }
 
+    public static Config getInstance() {
+        if (instance == null) {
+            instance = new Config();
+        }
+        return instance;
     }
 
     private void setDefaultFrameworkDirectory() {
@@ -105,6 +126,13 @@ public void setDecodeSources(short mode) throws AndrolibException {
         decodeSources = mode;
     }
 
+    public void setDecodeResolveMode(short mode) throws AndrolibException {
+        if (mode != DECODE_RES_RESOLVE_REMOVE && mode != DECODE_RES_RESOLVE_DUMMY && mode != DECODE_RES_RESOLVE_RETAIN) {
+            throw new AndrolibException("Invalid decode resources mode");
+        }
+        decodeResolveMode = mode;
+    }
+
     public void setDecodeResources(short mode) throws AndrolibException {
         if (mode != DECODE_RESOURCES_NONE && mode != DECODE_RESOURCES_FULL) {
             throw new AndrolibException("Invalid decode resources mode");

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/ResResSpec.java

@@ -105,6 +105,10 @@ public ResTypeSpec getType() {
         return mType;
     }
 
+    public boolean isDummyResSpec() {
+        return getName().startsWith("APKTOOL_DUMMY_");
+    }
+
     public void addResource(ResResource res) throws AndrolibException {
         addResource(res, false);
     }

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/ResTable.java

@@ -70,6 +70,10 @@ public boolean getAnalysisMode() {
         return mConfig.analysisMode;
     }
 
+    public Config getConfig() {
+        return mConfig;
+    }
+
     public boolean isMainPkgLoaded() {
         return mMainPkgLoaded;
     }

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/arsc/FlagItem.java

@@ -0,0 +1,41 @@
+/*
+ *  Copyright (C) 2010 Ryszard Wiśniewski <brut.alll@gmail.com>
+ *  Copyright (C) 2010 Connor Tumbleson <connor.tumbleson@gmail.com>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package brut.androlib.res.data.arsc;
+
+import brut.androlib.exceptions.AndrolibException;
+import brut.androlib.res.data.value.ResReferenceValue;
+
+public class FlagItem {
+    public final ResReferenceValue ref;
+    public final int flag;
+    public String value;
+
+    public FlagItem(ResReferenceValue ref, int flag) {
+        this.ref = ref;
+        this.flag = flag;
+    }
+
+    public String getValue() throws AndrolibException {
+        if (value == null) {
+            if (ref.referentIsNull()) {
+                return String.format("APKTOOL_MISSING_0x%08x", ref.getRawIntValue());
+            }
+            value = ref.getReferent().getName();
+        }
+        return value;
+    }
+}

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResEnumAttr.java

@@ -25,6 +25,7 @@
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.logging.Logger;
 
 public class ResEnumAttr extends ResAttr {
     ResEnumAttr(ResReferenceValue parent, int type, Integer min, Integer max,
@@ -46,15 +47,21 @@ public String convertToResXmlFormat(ResScalarValue value)
     }
 
     @Override
-    protected void serializeBody(XmlSerializer serializer, ResResource res)
-            throws AndrolibException, IOException {
+    protected void serializeBody(XmlSerializer serializer, ResResource res) throws AndrolibException, IOException {
         for (Duo<ResReferenceValue, ResIntValue> duo : mItems) {
             int intVal = duo.m2.getValue();
+
+            // #2836 - Support skipping items if the resource cannot be identified.
             ResResSpec m1Referent = duo.m1.getReferent();
+            if (m1Referent == null && shouldRemoveUnknownRes()) {
+                LOGGER.fine(String.format("null enum reference: m1=0x%08x(%s), m2=0x%08x(%s)",
+                    duo.m1.getRawIntValue(), duo.m1.getType(), duo.m2.getRawIntValue(), duo.m2.getType()));
+                continue;
+            }
 
             serializer.startTag(null, "enum");
             serializer.attribute(null, "name",
-                    m1Referent != null ? m1Referent.getName() : "@null"
+                m1Referent != null ? m1Referent.getName() : String.format("APKTOOL_MISSING_0x%08x", duo.m1.getRawIntValue())
             );
             serializer.attribute(null, "value", String.valueOf(intVal));
             serializer.endTag(null, "enum");
@@ -81,4 +88,6 @@ private String decodeValue(int value) throws AndrolibException {
 
     private final Duo<ResReferenceValue, ResIntValue>[] mItems;
     private final Map<Integer, String> mItemsCache = new HashMap<>();
+
+    private static final Logger LOGGER = Logger.getLogger(ResEnumAttr.class.getName());
 }

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResFlagsAttr.java

@@ -17,12 +17,15 @@
 package brut.androlib.res.data.value;
 
 import brut.androlib.exceptions.AndrolibException;
+import brut.androlib.res.data.ResResSpec;
 import brut.androlib.res.data.ResResource;
+import brut.androlib.res.data.arsc.FlagItem;
 import brut.util.Duo;
 import org.xmlpull.v1.XmlSerializer;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.logging.Logger;
 
 public class ResFlagsAttr extends ResAttr {
     ResFlagsAttr(ResReferenceValue parent, int type, Integer min, Integer max,
@@ -38,7 +41,7 @@ public class ResFlagsAttr extends ResAttr {
     @Override
     public String convertToResXmlFormat(ResScalarValue value)
             throws AndrolibException {
-        if(value instanceof ResReferenceValue) {
+        if (value instanceof ResReferenceValue) {
             return value.encodeAsResXml();
         }
         if (!(value instanceof ResIntValue)) {
@@ -70,13 +73,19 @@ public String convertToResXmlFormat(ResScalarValue value)
     }
 
     @Override
-    protected void serializeBody(XmlSerializer serializer, ResResource res)
-            throws AndrolibException, IOException {
+    protected void serializeBody(XmlSerializer serializer, ResResource res) throws AndrolibException, IOException {
         for (FlagItem item : mItems) {
+            ResResSpec referent = item.ref.getReferent();
+
+            // #2836 - Support skipping items if the resource cannot be identified.
+            if (referent == null && shouldRemoveUnknownRes()) {
+                LOGGER.fine(String.format("null flag reference: 0x%08x(%s)", item.ref.getValue(), item.ref.getType()));
+                continue;
+            }
+
             serializer.startTag(null, "flag");
             serializer.attribute(null, "name", item.getValue());
-            serializer.attribute(null, "value",
-                String.format("0x%08x", item.flag));
+            serializer.attribute(null, "value", String.format("0x%08x", item.flag));
             serializer.endTag(null, "flag");
         }
     }
@@ -130,24 +139,5 @@ private void loadFlags() {
     private FlagItem[] mZeroFlags;
     private FlagItem[] mFlags;
 
-    private static class FlagItem {
-        public final ResReferenceValue ref;
-        public final int flag;
-        public String value;
-
-        public FlagItem(ResReferenceValue ref, int flag) {
-            this.ref = ref;
-            this.flag = flag;
-        }
-
-        public String getValue() throws AndrolibException {
-            if (value == null) {
-                if (ref.referentIsNull()) {
-                    return "@null";
-                }
-                value = ref.getReferent().getName();
-            }
-            return value;
-        }
-    }
+    private static final Logger LOGGER = Logger.getLogger(ResFlagsAttr.class.getName());
 }

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResScalarValue.java

@@ -81,6 +81,11 @@ public void serializeToResValuesXml(XmlSerializer serializer,
             }
         }
 
+        // Dummy attributes should be <item> with type attribute
+        if (res.getResSpec().isDummyResSpec()) {
+            item = true;
+        }
+
         // Android does not allow values (false) for ids.xml anymore
         // https://issuetracker.google.com/issues/80475496
         // But it decodes as a ResBoolean, which makes no sense. So force it to empty

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResStyleValue.java

@@ -53,7 +53,7 @@ public void serializeToResValuesXml(XmlSerializer serializer,
             ResResSpec spec = mItem.m1.getReferent();
 
             if (spec == null) {
-                LOGGER.fine(String.format("null reference: m1=0x%08x(%s), m2=0x%08x(%s)",
+                LOGGER.fine(String.format("null style reference: m1=0x%08x(%s), m2=0x%08x(%s)",
                     mItem.m1.getRawIntValue(), mItem.m1.getType(), mItem.m2.getRawIntValue(), mItem.m2.getType()));
                 continue;
             }

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResValue.java

@@ -16,6 +16,10 @@
  */
 package brut.androlib.res.data.value;
 
-public class ResValue {
+import brut.androlib.Config;
 
+public class ResValue {
+    public boolean shouldRemoveUnknownRes() {
+        return Config.getInstance().isDecodeResolveModeRemoving();
+    }
 }