Add function to return path for last resolved resource

After an AssetManager.FindEntry call is made, either directly or from any of the resource entry calls, a stack of the steps taken to resolve the resource is saved. Those steps can be retrieved as a log later on by calling AssetManager.GetLastResourceResolution, which returns a formatted string of the resource ID/name and path taken, including the configs and package names of each step.

Logging and the saving of the steps to memory can be enabled/disabled with the @hide .setResourceResolutionLoggingEnabled() method on AssetManager.

Bug: 122374289

Test: cases for single and multi ApkAssets loaded
Test: case for no resolution made
Test: made test app to display log on device
Test: added debugging call to source and ran through on-device apps

Change-Id: I6a32b8d4020c3f8510032ff7f431510089fff43f

9 files changed, 471 insertions, 86 deletions

diff --git a/core/java/android/content/res/AssetManager.java b/core/java/android/content/res/AssetManager.java
index f1a4db25cd14..9e0a9ba0dc7b 100644
--- a/core/java/android/content/res/AssetManager.java
+++ b/core/java/android/content/res/AssetManager.java
@@ -732,6 +732,38 @@ public final class AssetManager implements AutoCloseable {
         }
     }
 
+    /**
+     * Enable resource resolution logging to track the steps taken to resolve the last resource
+     * entry retrieved. Stores the configuration and package names for each step.
+     *
+     * Default disabled.
+     *
+     * @param enabled Boolean indicating whether to enable or disable logging.
+     *
+     * @hide
+     */
+    public void setResourceResolutionLoggingEnabled(boolean enabled) {
+        synchronized (this) {
+            ensureValidLocked();
+            nativeSetResourceResolutionLoggingEnabled(mObject, enabled);
+        }
+    }
+
+    /**
+     * Retrieve the last resource resolution path logged.
+     *
+     * @return Formatted string containing last resource ID/name and steps taken to resolve final
+     * entry, including configuration and package names.
+     *
+     * @hide
+     */
+    public @Nullable String getLastResourceResolution() {
+        synchronized (this) {
+            ensureValidLocked();
+            return nativeGetLastResourceResolution(mObject);
+        }
+    }
+
     CharSequence getPooledStringForCookie(int cookie, int id) {
         // Cookies map to ApkAssets starting at 1.
         return getApkAssets()[cookie - 1].getStringFromPool(id);
@@ -1383,6 +1415,8 @@ public final class AssetManager implements AutoCloseable {
     private static native @Nullable String nativeGetResourceEntryName(long ptr, @AnyRes int resid);
     private static native @Nullable String[] nativeGetLocales(long ptr, boolean excludeSystem);
     private static native @Nullable Configuration[] nativeGetSizeConfigurations(long ptr);
+    private static native void nativeSetResourceResolutionLoggingEnabled(long ptr, boolean enabled);
+    private static native @Nullable String nativeGetLastResourceResolution(long ptr);
 
     // Style attribute retrieval native methods.
     private static native void nativeApplyStyle(long ptr, long themePtr, @AttrRes int defStyleAttr,
diff --git a/core/java/android/content/res/Resources.java b/core/java/android/content/res/Resources.java
index 365ceac68ee1..c4b315ec90c8 100644
--- a/core/java/android/content/res/Resources.java
+++ b/core/java/android/content/res/Resources.java
@@ -2010,22 +2010,36 @@ public class Resources {
     public String getResourceTypeName(@AnyRes int resid) throws NotFoundException {
         return mResourcesImpl.getResourceTypeName(resid);
     }
-    
+
     /**
      * Return the entry name for a given resource identifier.
-     * 
+     *
      * @param resid The resource identifier whose entry name is to be
      * retrieved.
-     * 
+     *
      * @return A string holding the entry name of the resource.
-     * 
+     *
      * @throws NotFoundException Throws NotFoundException if the given ID does not exist.
-     * 
+     *
      * @see #getResourceName
      */
     public String getResourceEntryName(@AnyRes int resid) throws NotFoundException {
         return mResourcesImpl.getResourceEntryName(resid);
     }
+
+    /**
+     * Return formatted log of the last retrieved resource's resolution path.
+     *
+     * @return A string holding a formatted log of the steps taken to resolve the last resource.
+     *
+     * @throws NotFoundException Throws NotFoundException if there hasn't been a resource
+     * resolved yet.
+     *
+     * @hide
+     */
+    public String getLastResourceResolution() throws NotFoundException {
+        return mResourcesImpl.getLastResourceResolution();
+    }
     
     /**
      * Parse a series of {@link android.R.styleable#Extra <extra>} tags from
diff --git a/core/java/android/content/res/ResourcesImpl.java b/core/java/android/content/res/ResourcesImpl.java
index 2ad4f625ef8c..77796d9ebdf5 100644
--- a/core/java/android/content/res/ResourcesImpl.java
+++ b/core/java/android/content/res/ResourcesImpl.java
@@ -299,6 +299,13 @@ public class ResourcesImpl {
     }
 
     @NonNull
+    String getLastResourceResolution() throws NotFoundException {
+        String str = mAssets.getLastResourceResolution();
+        if (str != null) return str;
+        throw new NotFoundException("Associated AssetManager hasn't resolved a resource");
+    }
+
+    @NonNull
     CharSequence getQuantityText(@PluralsRes int id, int quantity) throws NotFoundException {
         PluralRules rule = getPluralRule();
         CharSequence res = mAssets.getResourceBagText(id,
diff --git a/core/jni/android_util_AssetManager.cpp b/core/jni/android_util_AssetManager.cpp
index 7b564ae162ce..4101c04162af 100644
--- a/core/jni/android_util_AssetManager.cpp
+++ b/core/jni/android_util_AssetManager.cpp
@@ -44,6 +44,8 @@
 #include "androidfw/MutexGuard.h"
 #include "androidfw/PosixUtils.h"
 #include "androidfw/ResourceTypes.h"
+#include "androidfw/ResourceUtils.h"
+
 #include "core_jni_helpers.h"
 #include "jni.h"
 #include "nativehelper/JNIHelp.h"
@@ -975,34 +977,7 @@ static jstring NativeGetResourceName(JNIEnv* env, jclass /*clazz*/, jlong ptr, j
     return nullptr;
   }
 
-  std::string result;
-  if (name.package != nullptr) {
-    result.append(name.package, name.package_len);
-  }
-
-  if (name.type != nullptr || name.type16 != nullptr) {
-    if (!result.empty()) {
-      result += ":";
-    }
-
-    if (name.type != nullptr) {
-      result.append(name.type, name.type_len);
-    } else {
-      result += util::Utf16ToUtf8(StringPiece16(name.type16, name.type_len));
-    }
-  }
-
-  if (name.entry != nullptr || name.entry16 != nullptr) {
-    if (!result.empty()) {
-      result += "/";
-    }
-
-    if (name.entry != nullptr) {
-      result.append(name.entry, name.entry_len);
-    } else {
-      result += util::Utf16ToUtf8(StringPiece16(name.entry16, name.entry_len));
-    }
-  }
+  std::string result = ToFormattedResourceString(&name);
   return env->NewStringUTF(result.c_str());
 }
 
@@ -1049,6 +1024,26 @@ static jstring NativeGetResourceEntryName(JNIEnv* env, jclass /*clazz*/, jlong p
   return nullptr;
 }
 
+static void NativeSetResourceResolutionLoggingEnabled(JNIEnv* /*env*/,
+                                                      jclass /*clazz*/,
+                                                      jlong ptr,
+                                                      jboolean enabled) {
+  ScopedLock<AssetManager2> assetmanager(AssetManagerFromLong(ptr));
+  assetmanager->SetResourceResolutionLoggingEnabled(enabled);
+}
+
+static jstring NativeGetLastResourceResolution(JNIEnv* env,
+                                               jclass /*clazz*/,
+                                               jlong ptr) {
+  ScopedLock<AssetManager2> assetmanager(AssetManagerFromLong(ptr));
+  std::string resolution = assetmanager->GetLastResourceResolution();
+  if (resolution.empty()) {
+    return nullptr;
+  } else {
+    return env->NewStringUTF(resolution.c_str());
+  }
+}
+
 static jobjectArray NativeGetLocales(JNIEnv* env, jclass /*class*/, jlong ptr,
                                      jboolean exclude_system) {
   ScopedLock<AssetManager2> assetmanager(AssetManagerFromLong(ptr));
@@ -1452,6 +1447,10 @@ static const JNINativeMethod gAssetManagerMethods[] = {
     {"nativeGetResourcePackageName", "(JI)Ljava/lang/String;", (void*)NativeGetResourcePackageName},
     {"nativeGetResourceTypeName", "(JI)Ljava/lang/String;", (void*)NativeGetResourceTypeName},
     {"nativeGetResourceEntryName", "(JI)Ljava/lang/String;", (void*)NativeGetResourceEntryName},
+    {"nativeSetResourceResolutionLoggingEnabled", "(JZ)V",
+     (void*) NativeSetResourceResolutionLoggingEnabled},
+    {"nativeGetLastResourceResolution", "(J)Ljava/lang/String;",
+     (void*) NativeGetLastResourceResolution},
     {"nativeGetLocales", "(JZ)[Ljava/lang/String;", (void*)NativeGetLocales},
     {"nativeGetSizeConfigurations", "(J)[Landroid/content/res/Configuration;",
      (void*)NativeGetSizeConfigurations},
diff --git a/libs/androidfw/AssetManager2.cpp b/libs/androidfw/AssetManager2.cpp
index ad9ec02648b1..3c35d9b33fc8 100644
--- a/libs/androidfw/AssetManager2.cpp
+++ b/libs/androidfw/AssetManager2.cpp
@@ -20,8 +20,9 @@
 
 #include <algorithm>
 #include <iterator>
-#include <set>
 #include <map>
+#include <set>
+#include <sstream>
 
 #include "android-base/logging.h"
 #include "android-base/stringprintf.h"
@@ -372,6 +373,9 @@ ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_overri
   uint32_t best_offset = 0u;
   uint32_t type_flags = 0u;
 
+  Resolution::Step::Type resolution_type;
+  std::vector<Resolution::Step> resolution_steps;
+
   // If desired_config is the same as the set configuration, then we can use our filtered list
   // and we don't need to match the configurations, since they already matched.
   const bool use_fast_path = desired_config == &configuration_;
@@ -403,8 +407,8 @@ ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_overri
     // If the package is an overlay, then even configurations that are the same MUST be chosen.
     const bool package_is_overlay = loaded_package->IsOverlay();
 
-    const FilteredConfigGroup& filtered_group = loaded_package_impl.filtered_configs_[type_idx];
     if (use_fast_path) {
+      const FilteredConfigGroup& filtered_group = loaded_package_impl.filtered_configs_[type_idx];
       const std::vector<ResTable_config>& candidate_configs = filtered_group.configurations;
       const size_t type_count = candidate_configs.size();
       for (uint32_t i = 0; i < type_count; i++) {
@@ -412,21 +416,34 @@ ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_overri
 
         // We can skip calling ResTable_config::match() because we know that all candidate
         // configurations that do NOT match have been filtered-out.
-        if ((best_config == nullptr || this_config.isBetterThan(*best_config, desired_config)) ||
-            (package_is_overlay && this_config.compare(*best_config) == 0)) {
-          // The configuration matches and is better than the previous selection.
-          // Find the entry value if it exists for this configuration.
-          const ResTable_type* type_chunk = filtered_group.types[i];
-          const uint32_t offset = LoadedPackage::GetEntryOffset(type_chunk, local_entry_idx);
-          if (offset == ResTable_type::NO_ENTRY) {
-            continue;
-          }
+        if (best_config == nullptr) {
+          resolution_type = Resolution::Step::Type::INITIAL;
+        } else if (this_config.isBetterThan(*best_config, desired_config)) {
+          resolution_type = Resolution::Step::Type::BETTER_MATCH;
+        } else if (package_is_overlay && this_config.compare(*best_config) == 0) {
+          resolution_type = Resolution::Step::Type::OVERLAID;
+        } else {
+          continue;
+        }
+
+        // The configuration matches and is better than the previous selection.
+        // Find the entry value if it exists for this configuration.
+        const ResTable_type* type = filtered_group.types[i];
+        const uint32_t offset = LoadedPackage::GetEntryOffset(type, local_entry_idx);
+        if (offset == ResTable_type::NO_ENTRY) {
+          continue;
+        }
 
-          best_cookie = cookie;
-          best_package = loaded_package;
-          best_type = type_chunk;
-          best_config = &this_config;
-          best_offset = offset;
+        best_cookie = cookie;
+        best_package = loaded_package;
+        best_type = type;
+        best_config = &this_config;
+        best_offset = offset;
+
+        if (resource_resolution_logging_enabled_) {
+          resolution_steps.push_back(Resolution::Step{resolution_type,
+                                                      this_config.toString(),
+                                                      &loaded_package->GetPackageName()});
         }
       }
     } else {
@@ -440,23 +457,38 @@ ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_overri
         ResTable_config this_config;
         this_config.copyFromDtoH((*iter)->config);
 
-        if (this_config.match(*desired_config)) {
-          if ((best_config == nullptr || this_config.isBetterThan(*best_config, desired_config)) ||
-              (package_is_overlay && this_config.compare(*best_config) == 0)) {
-            // The configuration matches and is better than the previous selection.
-            // Find the entry value if it exists for this configuration.
-            const uint32_t offset = LoadedPackage::GetEntryOffset(*iter, local_entry_idx);
-            if (offset == ResTable_type::NO_ENTRY) {
-              continue;
-            }
+        if (!this_config.match(*desired_config)) {
+          continue;
+        }
 
-            best_cookie = cookie;
-            best_package = loaded_package;
-            best_type = *iter;
-            best_config_copy = this_config;
-            best_config = &best_config_copy;
-            best_offset = offset;
-          }
+        if (best_config == nullptr) {
+          resolution_type = Resolution::Step::Type::INITIAL;
+        } else if (this_config.isBetterThan(*best_config, desired_config)) {
+          resolution_type = Resolution::Step::Type::BETTER_MATCH;
+        } else if (package_is_overlay && this_config.compare(*best_config) == 0) {
+          resolution_type = Resolution::Step::Type::OVERLAID;
+        } else {
+          continue;
+        }
+
+        // The configuration matches and is better than the previous selection.
+        // Find the entry value if it exists for this configuration.
+        const uint32_t offset = LoadedPackage::GetEntryOffset(*iter, local_entry_idx);
+        if (offset == ResTable_type::NO_ENTRY) {
+          continue;
+        }
+
+        best_cookie = cookie;
+        best_package = loaded_package;
+        best_type = *iter;
+        best_config_copy = this_config;
+        best_config = &best_config_copy;
+        best_offset = offset;
+
+        if (resource_resolution_logging_enabled_) {
+          resolution_steps.push_back(Resolution::Step{resolution_type,
+                                                      this_config.toString(),
+                                                      &loaded_package->GetPackageName()});
         }
       }
     }
@@ -478,9 +510,95 @@ ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_overri
   out_entry->entry_string_ref =
       StringPoolRef(best_package->GetKeyStringPool(), best_entry->key.index);
   out_entry->dynamic_ref_table = &package_group.dynamic_ref_table;
+
+  if (resource_resolution_logging_enabled_) {
+    last_resolution.resid = resid;
+    last_resolution.cookie = best_cookie;
+    last_resolution.steps = resolution_steps;
+
+    // Cache only the type/entry refs since that's all that's needed to build name
+    last_resolution.type_string_ref =
+        StringPoolRef(best_package->GetTypeStringPool(), best_type->id - 1);
+    last_resolution.entry_string_ref =
+        StringPoolRef(best_package->GetKeyStringPool(), best_entry->key.index);
+  }
+
   return best_cookie;
 }
 
+void AssetManager2::SetResourceResolutionLoggingEnabled(bool enabled) {
+  resource_resolution_logging_enabled_ = enabled;
+
+  if (!enabled) {
+    last_resolution.cookie = kInvalidCookie;
+    last_resolution.resid = 0;
+    last_resolution.steps.clear();
+    last_resolution.type_string_ref = StringPoolRef();
+    last_resolution.entry_string_ref = StringPoolRef();
+  }
+}
+
+std::string AssetManager2::GetLastResourceResolution() const {
+  if (!resource_resolution_logging_enabled_) {
+    LOG(ERROR) << "Must enable resource resolution logging before getting path.";
+    return std::string();
+  }
+
+  auto cookie = last_resolution.cookie;
+  if (cookie == kInvalidCookie) {
+    LOG(ERROR) << "AssetManager hasn't resolved a resource to read resolution path.";
+    return std::string();
+  }
+
+  uint32_t resid = last_resolution.resid;
+  std::vector<Resolution::Step>& steps = last_resolution.steps;
+
+  ResourceName resource_name;
+  std::string resource_name_string;
+
+  const LoadedPackage* package =
+      apk_assets_[cookie]->GetLoadedArsc()->GetPackageById(get_package_id(resid));
+
+  if (package != nullptr) {
+    ToResourceName(last_resolution.type_string_ref,
+                   last_resolution.entry_string_ref,
+                   package,
+                   &resource_name);
+    resource_name_string = ToFormattedResourceString(&resource_name);
+  }
+
+  std::stringstream log_stream;
+  log_stream << base::StringPrintf("Resolution for 0x%08x ", resid)
+            << resource_name_string
+            << "\n\tFor config -"
+            << configuration_.toString();
+
+  std::string prefix;
+  for (Resolution::Step step : steps) {
+    switch (step.type) {
+      case Resolution::Step::Type::INITIAL:
+        prefix = "Found initial";
+        break;
+      case Resolution::Step::Type::BETTER_MATCH:
+        prefix = "Found better";
+        break;
+      case Resolution::Step::Type::OVERLAID:
+        prefix = "Overlaid";
+        break;
+    }
+
+    if (!prefix.empty()) {
+      log_stream << "\n\t" << prefix << ": " << *step.package_name;
+
+      if (!step.config_name.isEmpty()) {
+        log_stream << " -" << step.config_name;
+      }
+    }
+  }
+
+  return log_stream.str();
+}
+
 bool AssetManager2::GetResourceName(uint32_t resid, ResourceName* out_name) const {
   FindEntryResult entry;
   ApkAssetsCookie cookie =
@@ -495,27 +613,10 @@ bool AssetManager2::GetResourceName(uint32_t resid, ResourceName* out_name) cons
     return false;
   }
 
-  out_name->package = package->GetPackageName().data();
-  out_name->package_len = package->GetPackageName().size();
-
-  out_name->type = entry.type_string_ref.string8(&out_name->type_len);
-  out_name->type16 = nullptr;
-  if (out_name->type == nullptr) {
-    out_name->type16 = entry.type_string_ref.string16(&out_name->type_len);
-    if (out_name->type16 == nullptr) {
-      return false;
-    }
-  }
-
-  out_name->entry = entry.entry_string_ref.string8(&out_name->entry_len);
-  out_name->entry16 = nullptr;
-  if (out_name->entry == nullptr) {
-    out_name->entry16 = entry.entry_string_ref.string16(&out_name->entry_len);
-    if (out_name->entry16 == nullptr) {
-      return false;
-    }
-  }
-  return true;
+  return ToResourceName(entry.type_string_ref,
+                        entry.entry_string_ref,
+                        package,
+                        out_name);
 }
 
 bool AssetManager2::GetResourceFlags(uint32_t resid, uint32_t* out_flags) const {
diff --git a/libs/androidfw/ResourceUtils.cpp b/libs/androidfw/ResourceUtils.cpp
index d63feb01ef83..645984d85c34 100644
--- a/libs/androidfw/ResourceUtils.cpp
+++ b/libs/androidfw/ResourceUtils.cpp
@@ -48,4 +48,65 @@ bool ExtractResourceName(const StringPiece& str, StringPiece* out_package, Strin
          !(has_type_separator && out_type->empty());
 }
 
+bool ToResourceName(StringPoolRef& type_string_ref,
+                    StringPoolRef& entry_string_ref,
+                    const LoadedPackage* package,
+                    AssetManager2::ResourceName* out_name) {
+  out_name->package = package->GetPackageName().data();
+  out_name->package_len = package->GetPackageName().size();
+
+  out_name->type = type_string_ref.string8(&out_name->type_len);
+  out_name->type16 = nullptr;
+  if (out_name->type == nullptr) {
+    out_name->type16 = type_string_ref.string16(&out_name->type_len);
+    if (out_name->type16 == nullptr) {
+      return false;
+    }
+  }
+
+  out_name->entry = entry_string_ref.string8(&out_name->entry_len);
+  out_name->entry16 = nullptr;
+  if (out_name->entry == nullptr) {
+    out_name->entry16 = entry_string_ref.string16(&out_name->entry_len);
+    if (out_name->entry16 == nullptr) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+std::string ToFormattedResourceString(AssetManager2::ResourceName* resource_name) {
+  std::string result;
+  if (resource_name->package != nullptr) {
+    result.append(resource_name->package, resource_name->package_len);
+  }
+
+  if (resource_name->type != nullptr || resource_name->type16 != nullptr) {
+    if (!result.empty()) {
+      result += ":";
+    }
+
+    if (resource_name->type != nullptr) {
+      result.append(resource_name->type, resource_name->type_len);
+    } else {
+      result += util::Utf16ToUtf8(StringPiece16(resource_name->type16, resource_name->type_len));
+    }
+  }
+
+  if (resource_name->entry != nullptr || resource_name->entry16 != nullptr) {
+    if (!result.empty()) {
+      result += "/";
+    }
+
+    if (resource_name->entry != nullptr) {
+      result.append(resource_name->entry, resource_name->entry_len);
+    } else {
+      result += util::Utf16ToUtf8(StringPiece16(resource_name->entry16, resource_name->entry_len));
+    }
+  }
+
+  return result;
+}
+
 }  // namespace android
diff --git a/libs/androidfw/include/androidfw/AssetManager2.h b/libs/androidfw/include/androidfw/AssetManager2.h
index 0d492984d41d..f29769b834d1 100644
--- a/libs/androidfw/include/androidfw/AssetManager2.h
+++ b/libs/androidfw/include/androidfw/AssetManager2.h
@@ -229,6 +229,14 @@ class AssetManager2 {
                                    ResTable_config* in_out_selected_config, uint32_t* in_out_flags,
                                    uint32_t* out_last_reference) const;
 
+  // Enables or disables resource resolution logging. Clears stored steps when
+  // disabled.
+  void SetResourceResolutionLoggingEnabled(bool enabled);
+
+  // Returns formatted log of last resource resolution path, or empty if no
+  // resource has been resolved yet.
+  std::string GetLastResourceResolution() const;
+
   // Retrieves the best matching bag/map resource with ID `resid`.
   // This method will resolve all parent references for this bag and merge keys with the child.
   // To iterate over the keys, use the following idiom:
@@ -346,6 +354,48 @@ class AssetManager2 {
   // Cached set of bags. These are cached because they can inherit keys from parent bags,
   // which involves some calculation.
   std::unordered_map<uint32_t, util::unique_cptr<ResolvedBag>> cached_bags_;
+
+  // Whether or not to save resource resolution steps
+  bool resource_resolution_logging_enabled_ = false;
+
+  struct Resolution {
+
+    struct Step {
+
+      enum class Type {
+        INITIAL,
+        BETTER_MATCH,
+        OVERLAID
+      };
+
+      // Marks what kind of override this step was.
+      Type type;
+
+      // Built name of configuration for this step.
+      String8 config_name;
+
+      // Marks the package name of the better resource found in this step.
+      const std::string* package_name;
+    };
+
+    // Last resolved resource ID.
+    uint32_t resid;
+
+    // Last resolved resource result cookie.
+    ApkAssetsCookie cookie = kInvalidCookie;
+
+    // Last resolved resource type.
+    StringPoolRef type_string_ref;
+
+    // Last resolved resource entry.
+    StringPoolRef entry_string_ref;
+
+    // Steps taken to resolve last resource.
+    std::vector<Step> steps;
+  };
+
+  // Record of the last resolved resource's resolution path.
+  mutable Resolution last_resolution;
 };
 
 class Theme {
diff --git a/libs/androidfw/include/androidfw/ResourceUtils.h b/libs/androidfw/include/androidfw/ResourceUtils.h
index d94779bf5225..eb6eb8e66175 100644
--- a/libs/androidfw/include/androidfw/ResourceUtils.h
+++ b/libs/androidfw/include/androidfw/ResourceUtils.h
@@ -17,6 +17,7 @@
 #ifndef ANDROIDFW_RESOURCEUTILS_H
 #define ANDROIDFW_RESOURCEUTILS_H
 
+#include "androidfw/AssetManager2.h"
 #include "androidfw/StringPiece.h"
 
 namespace android {
@@ -27,6 +28,17 @@ namespace android {
 bool ExtractResourceName(const StringPiece& str, StringPiece* out_package, StringPiece* out_type,
                          StringPiece* out_entry);
 
+// Convert a type_string_ref, entry_string_ref, and package
+// to AssetManager2::ResourceName. Useful for getting
+// resource name without re-running AssetManager2::FindEntry searches.
+bool ToResourceName(StringPoolRef& type_string_ref,
+                    StringPoolRef& entry_string_ref,
+                    const LoadedPackage* package,
+                    AssetManager2::ResourceName* out_name);
+
+// Formats a ResourceName to "package:type/entry_name".
+std::string ToFormattedResourceString(AssetManager2::ResourceName* resource_name);
+
 inline uint32_t fix_package_id(uint32_t resid, uint8_t package_id) {
   return (resid & 0x00ffffffu) | (static_cast<uint32_t>(package_id) << 24);
 }
diff --git a/libs/androidfw/tests/AssetManager2_test.cpp b/libs/androidfw/tests/AssetManager2_test.cpp
index 5449a54d08de..105dcd209bf7 100644
--- a/libs/androidfw/tests/AssetManager2_test.cpp
+++ b/libs/androidfw/tests/AssetManager2_test.cpp
@@ -586,4 +586,111 @@ TEST_F(AssetManager2Test, OpenDirFromManyApks) {
   EXPECT_THAT(asset_dir->getFileType(2), Eq(FileType::kFileTypeDirectory));
 }
 
+TEST_F(AssetManager2Test, GetLastPathWithoutEnablingReturnsEmpty) {
+  ResTable_config desired_config;
+
+  AssetManager2 assetmanager;
+  assetmanager.SetConfiguration(desired_config);
+  assetmanager.SetApkAssets({basic_assets_.get()});
+  assetmanager.SetResourceResolutionLoggingEnabled(false);
+
+  Res_value value;
+  ResTable_config selected_config;
+  uint32_t flags;
+
+  ApkAssetsCookie cookie =
+      assetmanager.GetResource(basic::R::string::test1, false /*may_be_bag*/,
+                               0 /*density_override*/, &value, &selected_config, &flags);
+  ASSERT_NE(kInvalidCookie, cookie);
+
+  auto result = assetmanager.GetLastResourceResolution();
+  EXPECT_EQ("", result);
+}
+
+TEST_F(AssetManager2Test, GetLastPathWithoutResolutionReturnsEmpty) {
+  ResTable_config desired_config;
+
+  AssetManager2 assetmanager;
+  assetmanager.SetConfiguration(desired_config);
+  assetmanager.SetApkAssets({basic_assets_.get()});
+
+  auto result = assetmanager.GetLastResourceResolution();
+  EXPECT_EQ("", result);
+}
+
+TEST_F(AssetManager2Test, GetLastPathWithSingleApkAssets) {
+  ResTable_config desired_config;
+  memset(&desired_config, 0, sizeof(desired_config));
+  desired_config.language[0] = 'd';
+  desired_config.language[1] = 'e';
+
+  AssetManager2 assetmanager;
+  assetmanager.SetResourceResolutionLoggingEnabled(true);
+  assetmanager.SetConfiguration(desired_config);
+  assetmanager.SetApkAssets({basic_assets_.get()});
+
+  Res_value value;
+  ResTable_config selected_config;
+  uint32_t flags;
+
+  ApkAssetsCookie cookie =
+      assetmanager.GetResource(basic::R::string::test1, false /*may_be_bag*/,
+                               0 /*density_override*/, &value, &selected_config, &flags);
+  ASSERT_NE(kInvalidCookie, cookie);
+
+  auto result = assetmanager.GetLastResourceResolution();
+  EXPECT_EQ("Resolution for 0x7f030000 com.android.basic:string/test1\n\tFor config -de\n\tFound initial: com.android.basic", result);
+}
+
+TEST_F(AssetManager2Test, GetLastPathWithMultipleApkAssets) {
+  ResTable_config desired_config;
+  memset(&desired_config, 0, sizeof(desired_config));
+  desired_config.language[0] = 'd';
+  desired_config.language[1] = 'e';
+
+  AssetManager2 assetmanager;
+  assetmanager.SetResourceResolutionLoggingEnabled(true);
+  assetmanager.SetConfiguration(desired_config);
+  assetmanager.SetApkAssets({basic_assets_.get(), basic_de_fr_assets_.get()});
+
+  Res_value value = Res_value();
+  ResTable_config selected_config;
+  uint32_t flags;
+
+  ApkAssetsCookie cookie =
+      assetmanager.GetResource(basic::R::string::test1, false /*may_be_bag*/,
+                               0 /*density_override*/, &value, &selected_config, &flags);
+  ASSERT_NE(kInvalidCookie, cookie);
+
+  auto result = assetmanager.GetLastResourceResolution();
+  EXPECT_EQ("Resolution for 0x7f030000 com.android.basic:string/test1\n\tFor config -de\n\tFound initial: com.android.basic\n\tFound better: com.android.basic -de", result);
+}
+
+TEST_F(AssetManager2Test, GetLastPathAfterDisablingReturnsEmpty) {
+  ResTable_config desired_config;
+  memset(&desired_config, 0, sizeof(desired_config));
+
+  AssetManager2 assetmanager;
+  assetmanager.SetResourceResolutionLoggingEnabled(true);
+  assetmanager.SetConfiguration(desired_config);
+  assetmanager.SetApkAssets({basic_assets_.get()});
+
+  Res_value value = Res_value();
+  ResTable_config selected_config;
+  uint32_t flags;
+
+  ApkAssetsCookie cookie =
+      assetmanager.GetResource(basic::R::string::test1, false /*may_be_bag*/,
+                               0 /*density_override*/, &value, &selected_config, &flags);
+  ASSERT_NE(kInvalidCookie, cookie);
+
+  auto resultEnabled = assetmanager.GetLastResourceResolution();
+  ASSERT_NE("", resultEnabled);
+
+  assetmanager.SetResourceResolutionLoggingEnabled(false);
+
+  auto resultDisabled = assetmanager.GetLastResourceResolution();
+  EXPECT_EQ("", resultDisabled);
+}
+
 }  // namespace android