Revert "[res] Optimize isUpToDate() for ApkAssets"

Revert submission 31021037

Reason for revert: Droidmonitor created revert due to b/388342212. Will be verifying through ABTD before submission.

Reverted changes: /q/submissionid:31021037

Change-Id: I7d0eeaf7476c66f5276c68320f93f2b56953d531

11 files changed, 112 insertions, 208 deletions

diff --git a/core/java/android/content/res/ApkAssets.java b/core/java/android/content/res/ApkAssets.java
index b938aac811fd..908999b64961 100644
--- a/core/java/android/content/res/ApkAssets.java
+++ b/core/java/android/content/res/ApkAssets.java
@@ -25,7 +25,6 @@ import android.content.res.loader.ResourcesProvider;
 import android.ravenwood.annotation.RavenwoodClassLoadHook;
 import android.ravenwood.annotation.RavenwoodKeepWholeClass;
 import android.text.TextUtils;
-import android.util.Log;
 
 import com.android.internal.annotations.GuardedBy;
 
@@ -51,7 +50,6 @@ import java.util.Objects;
 @RavenwoodKeepWholeClass
 @RavenwoodClassLoadHook(RavenwoodClassLoadHook.LIBANDROID_LOADING_HOOK)
 public final class ApkAssets {
-    private static final boolean DEBUG = false;
 
     /**
      * The apk assets contains framework resource values specified by the system.
@@ -136,17 +134,6 @@ public final class ApkAssets {
     @Nullable
     private final AssetsProvider mAssets;
 
-    @NonNull
-    private String mName;
-
-    private static final int UPTODATE_FALSE = 0;
-    private static final int UPTODATE_TRUE = 1;
-    private static final int UPTODATE_ALWAYS_TRUE = 2;
-
-    // Start with the only value that may change later and would force a native call to
-    // double check it.
-    private int mPreviousUpToDateResult = UPTODATE_TRUE;
-
     /**
      * Creates a new ApkAssets instance from the given path on disk.
      *
@@ -317,7 +304,7 @@ public final class ApkAssets {
 
     private ApkAssets(@FormatType int format, @NonNull String path, @PropertyFlags int flags,
             @Nullable AssetsProvider assets) throws IOException {
-        this(format, flags, assets, path);
+        this(format, flags, assets);
         Objects.requireNonNull(path, "path");
         mNativePtr = nativeLoad(format, path, flags, assets);
         mStringBlock = new StringBlock(nativeGetStringBlock(mNativePtr), true /*useSparse*/);
@@ -326,7 +313,7 @@ public final class ApkAssets {
     private ApkAssets(@FormatType int format, @NonNull FileDescriptor fd,
             @NonNull String friendlyName, @PropertyFlags int flags, @Nullable AssetsProvider assets)
             throws IOException {
-        this(format, flags, assets, friendlyName);
+        this(format, flags, assets);
         Objects.requireNonNull(fd, "fd");
         Objects.requireNonNull(friendlyName, "friendlyName");
         mNativePtr = nativeLoadFd(format, fd, friendlyName, flags, assets);
@@ -336,7 +323,7 @@ public final class ApkAssets {
     private ApkAssets(@FormatType int format, @NonNull FileDescriptor fd,
             @NonNull String friendlyName, long offset, long length, @PropertyFlags int flags,
             @Nullable AssetsProvider assets) throws IOException {
-        this(format, flags, assets, friendlyName);
+        this(format, flags, assets);
         Objects.requireNonNull(fd, "fd");
         Objects.requireNonNull(friendlyName, "friendlyName");
         mNativePtr = nativeLoadFdOffsets(format, fd, friendlyName, offset, length, flags, assets);
@@ -344,17 +331,16 @@ public final class ApkAssets {
     }
 
     private ApkAssets(@PropertyFlags int flags, @Nullable AssetsProvider assets) {
-        this(FORMAT_APK, flags, assets, "empty");
+        this(FORMAT_APK, flags, assets);
         mNativePtr = nativeLoadEmpty(flags, assets);
         mStringBlock = null;
     }
 
     private ApkAssets(@FormatType int format, @PropertyFlags int flags,
-            @Nullable AssetsProvider assets, @NonNull String name) {
+            @Nullable AssetsProvider assets) {
         mFlags = flags;
         mAssets = assets;
         mIsOverlay = format == FORMAT_IDMAP;
-        if (DEBUG) mName = name;
     }
 
     @UnsupportedAppUsage
@@ -435,41 +421,13 @@ public final class ApkAssets {
         }
     }
 
-    private static double intervalMs(long beginNs, long endNs) {
-        return (endNs - beginNs) / 1000000.0;
-    }
-
     /**
      * Returns false if the underlying APK was changed since this ApkAssets was loaded.
      */
     public boolean isUpToDate() {
-        // This function is performance-critical - it's called multiple times on every Resources
-        // object creation, and on few other cache accesses - so it's important to avoid the native
-        // call when we know for sure what it will return (which is the case for both ALWAYS_TRUE
-        // and FALSE).
-        if (mPreviousUpToDateResult != UPTODATE_TRUE) {
-            return mPreviousUpToDateResult == UPTODATE_ALWAYS_TRUE;
-        }
-        final long beforeTs, afterLockTs, afterNativeTs, afterUnlockTs;
-        if (DEBUG) beforeTs = System.nanoTime();
-        final int res;
         synchronized (this) {
-            if (DEBUG) afterLockTs = System.nanoTime();
-            res = nativeIsUpToDate(mNativePtr);
-            if (DEBUG) afterNativeTs = System.nanoTime();
-        }
-        if (DEBUG) {
-            afterUnlockTs = System.nanoTime();
-            if (afterUnlockTs - beforeTs >= 10L * 1000000) {
-                Log.d("ApkAssets", "isUpToDate(" + mName + ") took "
-                        + intervalMs(beforeTs, afterUnlockTs)
-                        + " ms: " + intervalMs(beforeTs, afterLockTs)
-                        + " / " + intervalMs(afterLockTs, afterNativeTs)
-                        + " / " + intervalMs(afterNativeTs, afterUnlockTs));
-            }
+            return nativeIsUpToDate(mNativePtr);
         }
-        mPreviousUpToDateResult = res;
-        return res != UPTODATE_FALSE;
     }
 
     public boolean isSystem() {
@@ -529,7 +487,7 @@ public final class ApkAssets {
     private static native @NonNull String nativeGetAssetPath(long ptr);
     private static native @NonNull String nativeGetDebugName(long ptr);
     private static native long nativeGetStringBlock(long ptr);
-    @CriticalNative private static native int nativeIsUpToDate(long ptr);
+    @CriticalNative private static native boolean nativeIsUpToDate(long ptr);
     private static native long nativeOpenXml(long ptr, @NonNull String fileName) throws IOException;
     private static native @Nullable OverlayableInfo nativeGetOverlayableInfo(long ptr,
             String overlayableName) throws IOException;
diff --git a/core/jni/android_content_res_ApkAssets.cpp b/core/jni/android_content_res_ApkAssets.cpp
index 0da9b188ac5a..1e7bfe32ba79 100644
--- a/core/jni/android_content_res_ApkAssets.cpp
+++ b/core/jni/android_content_res_ApkAssets.cpp
@@ -129,8 +129,8 @@ class LoaderAssetsProvider : public AssetsProvider {
     return debug_name_;
   }
 
-  UpToDate IsUpToDate() const override {
-      return UpToDate::Always;
+  bool IsUpToDate() const override {
+    return true;
   }
 
   ~LoaderAssetsProvider() override {
@@ -443,10 +443,10 @@ static jlong NativeGetStringBlock(JNIEnv* /*env*/, jclass /*clazz*/, jlong ptr)
     return reinterpret_cast<jlong>(apk_assets->GetLoadedArsc()->GetStringPool());
 }
 
-static jint NativeIsUpToDate(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
+static jboolean NativeIsUpToDate(CRITICAL_JNI_PARAMS_COMMA jlong ptr) {
     auto scoped_apk_assets = ScopedLock(ApkAssetsFromLong(ptr));
     auto apk_assets = scoped_apk_assets->get();
-    return (jint)apk_assets->IsUpToDate();
+    return apk_assets->IsUpToDate() ? JNI_TRUE : JNI_FALSE;
 }
 
 static jlong NativeOpenXml(JNIEnv* env, jclass /*clazz*/, jlong ptr, jstring file_name) {
@@ -558,7 +558,7 @@ static const JNINativeMethod gApkAssetsMethods[] = {
         {"nativeGetDebugName", "(J)Ljava/lang/String;", (void*)NativeGetDebugName},
         {"nativeGetStringBlock", "(J)J", (void*)NativeGetStringBlock},
         // @CriticalNative
-        {"nativeIsUpToDate", "(J)I", (void*)NativeIsUpToDate},
+        {"nativeIsUpToDate", "(J)Z", (void*)NativeIsUpToDate},
         {"nativeOpenXml", "(JLjava/lang/String;)J", (void*)NativeOpenXml},
         {"nativeGetOverlayableInfo", "(JLjava/lang/String;)Landroid/content/om/OverlayableInfo;",
          (void*)NativeGetOverlayableInfo},
diff --git a/libs/androidfw/ApkAssets.cpp b/libs/androidfw/ApkAssets.cpp
index e693fcfd3918..dbb891455ddd 100644
--- a/libs/androidfw/ApkAssets.cpp
+++ b/libs/androidfw/ApkAssets.cpp
@@ -162,13 +162,10 @@ const std::string& ApkAssets::GetDebugName() const {
   return assets_provider_->GetDebugName();
 }
 
-UpToDate ApkAssets::IsUpToDate() const {
+bool ApkAssets::IsUpToDate() const {
   // Loaders are invalidated by the app, not the system, so assume they are up to date.
-  if (IsLoader()) {
-    return UpToDate::Always;
-  }
-  const auto idmap_res = loaded_idmap_ ? loaded_idmap_->IsUpToDate() : UpToDate::Always;
-  return combine(idmap_res, [this] { return assets_provider_->IsUpToDate(); });
+  return IsLoader() || ((!loaded_idmap_ || loaded_idmap_->IsUpToDate())
+                        && assets_provider_->IsUpToDate());
 }
 
 }  // namespace android
diff --git a/libs/androidfw/AssetsProvider.cpp b/libs/androidfw/AssetsProvider.cpp
index 59c6aba7b8b0..2d3c06506a1f 100644
--- a/libs/androidfw/AssetsProvider.cpp
+++ b/libs/androidfw/AssetsProvider.cpp
@@ -86,9 +86,11 @@ void ZipAssetsProvider::ZipCloser::operator()(ZipArchive* a) const {
 }
 
 ZipAssetsProvider::ZipAssetsProvider(ZipArchiveHandle handle, PathOrDebugName&& path,
-                                     package_property_t flags, ModDate last_mod_time)
-    : zip_handle_(handle), name_(std::move(path)), flags_(flags), last_mod_time_(last_mod_time) {
-}
+                                     package_property_t flags, time_t last_mod_time)
+    : zip_handle_(handle),
+      name_(std::move(path)),
+      flags_(flags),
+      last_mod_time_(last_mod_time) {}
 
 std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(std::string path,
                                                              package_property_t flags,
@@ -102,10 +104,10 @@ std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(std::string path,
     return {};
   }
 
-  ModDate mod_date = kInvalidModDate;
+  struct stat sb{.st_mtime = -1};
   // Skip all up-to-date checks if the file won't ever change.
-  if (isKnownWritablePath(path.c_str()) || !isReadonlyFilesystem(GetFileDescriptor(handle))) {
-    if (mod_date = getFileModDate(GetFileDescriptor(handle)); mod_date == kInvalidModDate) {
+  if (!isReadonlyFilesystem(path.c_str())) {
+    if ((released_fd < 0 ? stat(path.c_str(), &sb) : fstat(released_fd, &sb)) < 0) {
       // Stat requires execute permissions on all directories path to the file. If the process does
       // not have execute permissions on this file, allow the zip to be opened but IsUpToDate() will
       // always have to return true.
@@ -114,7 +116,7 @@ std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(std::string path,
   }
 
   return std::unique_ptr<ZipAssetsProvider>(
-      new ZipAssetsProvider(handle, PathOrDebugName::Path(std::move(path)), flags, mod_date));
+      new ZipAssetsProvider(handle, PathOrDebugName::Path(std::move(path)), flags, sb.st_mtime));
 }
 
 std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(base::unique_fd fd,
@@ -135,10 +137,10 @@ std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(base::unique_fd fd,
     return {};
   }
 
-  ModDate mod_date = kInvalidModDate;
+  struct stat sb{.st_mtime = -1};
   // Skip all up-to-date checks if the file won't ever change.
   if (!isReadonlyFilesystem(released_fd)) {
-    if (mod_date = getFileModDate(released_fd); mod_date == kInvalidModDate) {
+    if (fstat(released_fd, &sb) < 0) {
       // Stat requires execute permissions on all directories path to the file. If the process does
       // not have execute permissions on this file, allow the zip to be opened but IsUpToDate() will
       // always have to return true.
@@ -148,7 +150,7 @@ std::unique_ptr<ZipAssetsProvider> ZipAssetsProvider::Create(base::unique_fd fd,
   }
 
   return std::unique_ptr<ZipAssetsProvider>(new ZipAssetsProvider(
-      handle, PathOrDebugName::DebugName(std::move(friendly_name)), flags, mod_date));
+      handle, PathOrDebugName::DebugName(std::move(friendly_name)), flags, sb.st_mtime));
 }
 
 std::unique_ptr<Asset> ZipAssetsProvider::OpenInternal(const std::string& path,
@@ -280,16 +282,21 @@ const std::string& ZipAssetsProvider::GetDebugName() const {
   return name_.GetDebugName();
 }
 
-UpToDate ZipAssetsProvider::IsUpToDate() const {
-  if (last_mod_time_ == kInvalidModDate) {
-    return UpToDate::Always;
+bool ZipAssetsProvider::IsUpToDate() const {
+  if (last_mod_time_ == -1) {
+    return true;
+  }
+  struct stat sb{};
+  if (fstat(GetFileDescriptor(zip_handle_.get()), &sb) < 0) {
+    // If fstat fails on the zip archive, return true so the zip archive the resource system does
+    // attempt to refresh the ApkAsset.
+    return true;
   }
-  return fromBool(last_mod_time_ == getFileModDate(GetFileDescriptor(zip_handle_.get())));
+  return last_mod_time_ == sb.st_mtime;
 }
 
-DirectoryAssetsProvider::DirectoryAssetsProvider(std::string&& path, ModDate last_mod_time)
-    : dir_(std::move(path)), last_mod_time_(last_mod_time) {
-}
+DirectoryAssetsProvider::DirectoryAssetsProvider(std::string&& path, time_t last_mod_time)
+    : dir_(std::move(path)), last_mod_time_(last_mod_time) {}
 
 std::unique_ptr<DirectoryAssetsProvider> DirectoryAssetsProvider::Create(std::string path) {
   struct stat sb;
@@ -310,7 +317,7 @@ std::unique_ptr<DirectoryAssetsProvider> DirectoryAssetsProvider::Create(std::st
 
   const bool isReadonly = isReadonlyFilesystem(path.c_str());
   return std::unique_ptr<DirectoryAssetsProvider>(
-      new DirectoryAssetsProvider(std::move(path), isReadonly ? kInvalidModDate : getModDate(sb)));
+      new DirectoryAssetsProvider(std::move(path), isReadonly ? -1 : sb.st_mtime));
 }
 
 std::unique_ptr<Asset> DirectoryAssetsProvider::OpenInternal(const std::string& path,
@@ -339,11 +346,17 @@ const std::string& DirectoryAssetsProvider::GetDebugName() const {
   return dir_;
 }
 
-UpToDate DirectoryAssetsProvider::IsUpToDate() const {
-  if (last_mod_time_ == kInvalidModDate) {
-    return UpToDate::Always;
+bool DirectoryAssetsProvider::IsUpToDate() const {
+  if (last_mod_time_ == -1) {
+    return true;
   }
-  return fromBool(last_mod_time_ == getFileModDate(dir_.c_str()));
+  struct stat sb;
+  if (stat(dir_.c_str(), &sb) < 0) {
+    // If stat fails on the zip archive, return true so the zip archive the resource system does
+    // attempt to refresh the ApkAsset.
+    return true;
+  }
+  return last_mod_time_ == sb.st_mtime;
 }
 
 MultiAssetsProvider::MultiAssetsProvider(std::unique_ptr<AssetsProvider>&& primary,
@@ -384,8 +397,8 @@ const std::string& MultiAssetsProvider::GetDebugName() const {
   return debug_name_;
 }
 
-UpToDate MultiAssetsProvider::IsUpToDate() const {
-  return combine(primary_->IsUpToDate(), [this] { return secondary_->IsUpToDate(); });
+bool MultiAssetsProvider::IsUpToDate() const {
+  return primary_->IsUpToDate() && secondary_->IsUpToDate();
 }
 
 EmptyAssetsProvider::EmptyAssetsProvider(std::optional<std::string>&& path) :
@@ -429,8 +442,8 @@ const std::string& EmptyAssetsProvider::GetDebugName() const {
   return kEmpty;
 }
 
-UpToDate EmptyAssetsProvider::IsUpToDate() const {
-  return UpToDate::Always;
+bool EmptyAssetsProvider::IsUpToDate() const {
+  return true;
 }
 
 }  // namespace android
diff --git a/libs/androidfw/Idmap.cpp b/libs/androidfw/Idmap.cpp
index 262e7df185b7..3ecd82b074a1 100644
--- a/libs/androidfw/Idmap.cpp
+++ b/libs/androidfw/Idmap.cpp
@@ -22,10 +22,9 @@
 #include "android-base/logging.h"
 #include "android-base/stringprintf.h"
 #include "android-base/utf8.h"
-#include "androidfw/AssetManager.h"
+#include "androidfw/misc.h"
 #include "androidfw/ResourceTypes.h"
 #include "androidfw/Util.h"
-#include "androidfw/misc.h"
 #include "utils/ByteOrder.h"
 #include "utils/Trace.h"
 
@@ -269,16 +268,11 @@ LoadedIdmap::LoadedIdmap(const std::string& idmap_path, const Idmap_header* head
       configurations_(configs),
       overlay_entries_(overlay_entries),
       string_pool_(std::move(string_pool)),
+      idmap_fd_(
+          android::base::utf8::open(idmap_path.c_str(), O_RDONLY | O_CLOEXEC | O_BINARY | O_PATH)),
       overlay_apk_path_(overlay_apk_path),
       target_apk_path_(target_apk_path),
-      idmap_last_mod_time_(kInvalidModDate) {
-  if (!isReadonlyFilesystem(std::string(overlay_apk_path_).c_str()) ||
-      !(target_apk_path_ == AssetManager::TARGET_APK_PATH ||
-        isReadonlyFilesystem(std::string(target_apk_path_).c_str()))) {
-    idmap_fd_.reset(
-        android::base::utf8::open(idmap_path.c_str(), O_RDONLY | O_CLOEXEC | O_BINARY | O_PATH));
-    idmap_last_mod_time_ = getFileModDate(idmap_fd_);
-  }
+      idmap_last_mod_time_(getFileModDate(idmap_fd_.get())) {
 }
 
 std::unique_ptr<LoadedIdmap> LoadedIdmap::Load(StringPiece idmap_path, StringPiece idmap_data) {
@@ -387,11 +381,8 @@ std::unique_ptr<LoadedIdmap> LoadedIdmap::Load(StringPiece idmap_path, StringPie
                       overlay_entries, std::move(idmap_string_pool), *overlay_path, *target_path));
 }
 
-UpToDate LoadedIdmap::IsUpToDate() const {
-  if (idmap_last_mod_time_ == kInvalidModDate) {
-    return UpToDate::Always;
-  }
-  return fromBool(idmap_last_mod_time_ == getFileModDate(idmap_fd_.get()));
+bool LoadedIdmap::IsUpToDate() const {
+  return idmap_last_mod_time_ == getFileModDate(idmap_fd_.get());
 }
 
 }  // namespace android
diff --git a/libs/androidfw/include/androidfw/ApkAssets.h b/libs/androidfw/include/androidfw/ApkAssets.h
index 3f6f4661f2f7..231808beb718 100644
--- a/libs/androidfw/include/androidfw/ApkAssets.h
+++ b/libs/androidfw/include/androidfw/ApkAssets.h
@@ -116,7 +116,7 @@ class ApkAssets : public RefBase {
     return resources_asset_ != nullptr && resources_asset_->isAllocated();
   }
 
-  UpToDate IsUpToDate() const;
+  bool IsUpToDate() const;
 
   // DANGER!
   // This is a destructive method that rips the assets provider out of ApkAssets object.
diff --git a/libs/androidfw/include/androidfw/AssetsProvider.h b/libs/androidfw/include/androidfw/AssetsProvider.h
index 46d7a57ab763..d33c325ff369 100644
--- a/libs/androidfw/include/androidfw/AssetsProvider.h
+++ b/libs/androidfw/include/androidfw/AssetsProvider.h
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-#pragma once
+#ifndef ANDROIDFW_ASSETSPROVIDER_H
+#define ANDROIDFW_ASSETSPROVIDER_H
 
 #include <memory>
 #include <string>
@@ -57,7 +58,7 @@ struct AssetsProvider {
   WARN_UNUSED virtual const std::string& GetDebugName() const = 0;
 
   // Returns whether the interface provides the most recent version of its files.
-  WARN_UNUSED virtual UpToDate IsUpToDate() const = 0;
+  WARN_UNUSED virtual bool IsUpToDate() const = 0;
 
   // Creates an Asset from a file on disk.
   static std::unique_ptr<Asset> CreateAssetFromFile(const std::string& path);
@@ -94,7 +95,7 @@ struct ZipAssetsProvider : public AssetsProvider {
 
   WARN_UNUSED std::optional<std::string_view> GetPath() const override;
   WARN_UNUSED const std::string& GetDebugName() const override;
-  WARN_UNUSED UpToDate IsUpToDate() const override;
+  WARN_UNUSED bool IsUpToDate() const override;
   WARN_UNUSED std::optional<uint32_t> GetCrc(std::string_view path) const;
 
   ~ZipAssetsProvider() override = default;
@@ -105,7 +106,7 @@ struct ZipAssetsProvider : public AssetsProvider {
  private:
   struct PathOrDebugName;
   ZipAssetsProvider(ZipArchive* handle, PathOrDebugName&& path, package_property_t flags,
-                    ModDate last_mod_time);
+                    time_t last_mod_time);
 
   struct PathOrDebugName {
     static PathOrDebugName Path(std::string value) {
@@ -134,7 +135,7 @@ struct ZipAssetsProvider : public AssetsProvider {
   std::unique_ptr<ZipArchive, ZipCloser> zip_handle_;
   PathOrDebugName name_;
   package_property_t flags_;
-  ModDate last_mod_time_;
+  time_t last_mod_time_;
 };
 
 // Supplies assets from a root directory.
@@ -146,7 +147,7 @@ struct DirectoryAssetsProvider : public AssetsProvider {
 
   WARN_UNUSED std::optional<std::string_view> GetPath() const override;
   WARN_UNUSED const std::string& GetDebugName() const override;
-  WARN_UNUSED UpToDate IsUpToDate() const override;
+  WARN_UNUSED bool IsUpToDate() const override;
 
   ~DirectoryAssetsProvider() override = default;
  protected:
@@ -155,9 +156,9 @@ struct DirectoryAssetsProvider : public AssetsProvider {
                                       bool* file_exists) const override;
 
  private:
-  explicit DirectoryAssetsProvider(std::string&& path, ModDate last_mod_time);
+  explicit DirectoryAssetsProvider(std::string&& path, time_t last_mod_time);
   std::string dir_;
-  ModDate last_mod_time_;
+  time_t last_mod_time_;
 };
 
 // Supplies assets from a `primary` asset provider and falls back to supplying assets from the
@@ -171,7 +172,7 @@ struct MultiAssetsProvider : public AssetsProvider {
 
   WARN_UNUSED std::optional<std::string_view> GetPath() const override;
   WARN_UNUSED const std::string& GetDebugName() const override;
-  WARN_UNUSED UpToDate IsUpToDate() const override;
+  WARN_UNUSED bool IsUpToDate() const override;
 
   ~MultiAssetsProvider() override = default;
  protected:
@@ -198,7 +199,7 @@ struct EmptyAssetsProvider : public AssetsProvider {
 
   WARN_UNUSED std::optional<std::string_view> GetPath() const override;
   WARN_UNUSED const std::string& GetDebugName() const override;
-  WARN_UNUSED UpToDate IsUpToDate() const override;
+  WARN_UNUSED bool IsUpToDate() const override;
 
   ~EmptyAssetsProvider() override = default;
  protected:
@@ -211,3 +212,5 @@ struct EmptyAssetsProvider : public AssetsProvider {
 };
 
 }  // namespace android
+
+#endif /* ANDROIDFW_ASSETSPROVIDER_H */
diff --git a/libs/androidfw/include/androidfw/Idmap.h b/libs/androidfw/include/androidfw/Idmap.h
index 87f3c9df9a91..ac75eb3bb98c 100644
--- a/libs/androidfw/include/androidfw/Idmap.h
+++ b/libs/androidfw/include/androidfw/Idmap.h
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-#pragma once
+#ifndef IDMAP_H_
+#define IDMAP_H_
 
 #include <memory>
 #include <string>
@@ -31,31 +32,6 @@
 
 namespace android {
 
-// An enum that tracks more states than just 'up to date' or 'not' for a resources container:
-// there are several cases where we know for sure that the object can't change and won't get
-// out of date. Reporting those states to the managed layer allows it to stop checking here
-// completely, speeding up the cache lookups by dozens of milliseconds.
-enum class UpToDate : int { False, True, Always };
-
-// Combines two UpToDate values, and only accesses the second one if it matters to the result.
-template <class Getter>
-UpToDate combine(UpToDate first, Getter secondGetter) {
-  switch (first) {
-    case UpToDate::False:
-      return UpToDate::False;
-    case UpToDate::True: {
-      const auto second = secondGetter();
-      return second == UpToDate::False ? UpToDate::False : UpToDate::True;
-    }
-    case UpToDate::Always:
-      return secondGetter();
-  }
-}
-
-inline UpToDate fromBool(bool value) {
-  return value ? UpToDate::True : UpToDate::False;
-}
-
 class LoadedIdmap;
 class IdmapResMap;
 struct Idmap_header;
@@ -220,7 +196,7 @@ class LoadedIdmap {
 
   // Returns whether the idmap file on disk has not been modified since the construction of this
   // LoadedIdmap.
-  UpToDate IsUpToDate() const;
+  bool IsUpToDate() const;
 
  protected:
   // Exposed as protected so that tests can subclass and mock this class out.
@@ -255,3 +231,5 @@ class LoadedIdmap {
 };
 
 }  // namespace android
+
+#endif  // IDMAP_H_
diff --git a/libs/androidfw/include/androidfw/misc.h b/libs/androidfw/include/androidfw/misc.h
index d8ca64a174a2..c9ba8a01a5e9 100644
--- a/libs/androidfw/include/androidfw/misc.h
+++ b/libs/androidfw/include/androidfw/misc.h
@@ -15,7 +15,6 @@
  */
 #pragma once
 
-#include <sys/stat.h>
 #include <time.h>
 
 //
@@ -65,15 +64,10 @@ ModDate getFileModDate(const char* fileName);
 /* same, but also returns -1 if the file has already been deleted */
 ModDate getFileModDate(int fd);
 
-// Extract the modification date from the stat structure.
-ModDate getModDate(const struct ::stat& st);
-
 // Check if |path| or |fd| resides on a readonly filesystem.
 bool isReadonlyFilesystem(const char* path);
 bool isReadonlyFilesystem(int fd);
 
-bool isKnownWritablePath(const char* path);
-
 }  // namespace android
 
 // Whoever uses getFileModDate() will need this as well
diff --git a/libs/androidfw/misc.cpp b/libs/androidfw/misc.cpp
index 26eb320805c9..32f3624a3aee 100644
--- a/libs/androidfw/misc.cpp
+++ b/libs/androidfw/misc.cpp
@@ -16,10 +16,10 @@
 
 #define LOG_TAG "misc"
 
-#include "androidfw/misc.h"
-
-#include <errno.h>
-#include <sys/stat.h>
+//
+// Miscellaneous utility functions.
+//
+#include <androidfw/misc.h>
 
 #include "android-base/logging.h"
 
@@ -28,7 +28,9 @@
 #include <sys/vfs.h>
 #endif  // __linux__
 
-#include <array>
+#include <errno.h>
+#include <sys/stat.h>
+
 #include <cstdio>
 #include <cstring>
 #include <tuple>
@@ -38,26 +40,28 @@ namespace android {
 /*
  * Get a file's type.
  */
-FileType getFileType(const char* fileName) {
-  struct stat sb;
-  if (stat(fileName, &sb) < 0) {
-    if (errno == ENOENT || errno == ENOTDIR)
-      return kFileTypeNonexistent;
-    else {
-      PLOG(ERROR) << "getFileType(): stat(" << fileName << ") failed";
-      return kFileTypeUnknown;
-    }
-  } else {
-    if (S_ISREG(sb.st_mode))
-      return kFileTypeRegular;
-    else if (S_ISDIR(sb.st_mode))
-      return kFileTypeDirectory;
-    else if (S_ISCHR(sb.st_mode))
-      return kFileTypeCharDev;
-    else if (S_ISBLK(sb.st_mode))
-      return kFileTypeBlockDev;
-    else if (S_ISFIFO(sb.st_mode))
-      return kFileTypeFifo;
+FileType getFileType(const char* fileName)
+{
+    struct stat sb;
+
+    if (stat(fileName, &sb) < 0) {
+        if (errno == ENOENT || errno == ENOTDIR)
+            return kFileTypeNonexistent;
+        else {
+            PLOG(ERROR) << "getFileType(): stat(" << fileName << ") failed";
+            return kFileTypeUnknown;
+        }
+    } else {
+        if (S_ISREG(sb.st_mode))
+            return kFileTypeRegular;
+        else if (S_ISDIR(sb.st_mode))
+            return kFileTypeDirectory;
+        else if (S_ISCHR(sb.st_mode))
+            return kFileTypeCharDev;
+        else if (S_ISBLK(sb.st_mode))
+            return kFileTypeBlockDev;
+        else if (S_ISFIFO(sb.st_mode))
+            return kFileTypeFifo;
 #if defined(S_ISLNK)
         else if (S_ISLNK(sb.st_mode))
             return kFileTypeSymlink;
@@ -71,7 +75,7 @@ FileType getFileType(const char* fileName) {
     }
 }
 
-ModDate getModDate(const struct stat& st) {
+static ModDate getModDate(const struct stat& st) {
 #ifdef _WIN32
   return st.st_mtime;
 #elif defined(__APPLE__)
@@ -109,14 +113,8 @@ bool isReadonlyFilesystem(const char*) {
 bool isReadonlyFilesystem(int) {
     return false;
 }
-bool isKnownWritablePath(const char*) {
-  return false;
-}
 #else   // __linux__
 bool isReadonlyFilesystem(const char* path) {
-  if (isKnownWritablePath(path)) {
-    return false;
-  }
     struct statfs sfs;
     if (::statfs(path, &sfs)) {
         PLOG(ERROR) << "isReadonlyFilesystem(): statfs(" << path << ") failed";
@@ -133,13 +131,6 @@ bool isReadonlyFilesystem(int fd) {
     }
     return (sfs.f_flags & ST_RDONLY) != 0;
 }
-
-bool isKnownWritablePath(const char* path) {
-  // We know that all paths in /data/ are writable.
-  static constexpr char kRwPrefix[] = "/data/";
-  return strncmp(kRwPrefix, path, std::size(kRwPrefix) - 1) == 0;
-}
-
 #endif  // __linux__
 
 }  // namespace android
diff --git a/libs/androidfw/tests/Idmap_test.cpp b/libs/androidfw/tests/Idmap_test.cpp
index 22b9e69500d9..cb2e56f5f5e4 100644
--- a/libs/androidfw/tests/Idmap_test.cpp
+++ b/libs/androidfw/tests/Idmap_test.cpp
@@ -218,11 +218,10 @@ TEST_F(IdmapTest, OverlayAssetsIsUpToDate) {
 
   auto apk_assets = ApkAssets::LoadOverlay(temp_file.path);
   ASSERT_NE(nullptr, apk_assets);
-  ASSERT_TRUE(apk_assets->IsOverlay());
-  ASSERT_EQ(UpToDate::True, apk_assets->IsUpToDate());
+  ASSERT_TRUE(apk_assets->IsUpToDate());
 
   unlink(temp_file.path);
-  ASSERT_EQ(UpToDate::False, apk_assets->IsUpToDate());
+  ASSERT_FALSE(apk_assets->IsUpToDate());
 
   const auto sleep_duration =
       std::chrono::nanoseconds(std::max(kModDateResolutionNs, 1'000'000ull));
@@ -231,27 +230,7 @@ TEST_F(IdmapTest, OverlayAssetsIsUpToDate) {
   base::WriteStringToFile("hello", temp_file.path);
   std::this_thread::sleep_for(sleep_duration);
 
-  ASSERT_EQ(UpToDate::False, apk_assets->IsUpToDate());
-}
-
-TEST(IdmapTestUpToDate, Combine) {
-  ASSERT_EQ(UpToDate::False, combine(UpToDate::False, [] {
-              ADD_FAILURE();  // Shouldn't get called at all.
-              return UpToDate::False;
-            }));
-
-  ASSERT_EQ(UpToDate::False, combine(UpToDate::True, [] { return UpToDate::False; }));
-
-  ASSERT_EQ(UpToDate::True, combine(UpToDate::True, [] { return UpToDate::True; }));
-  ASSERT_EQ(UpToDate::True, combine(UpToDate::True, [] { return UpToDate::Always; }));
-  ASSERT_EQ(UpToDate::True, combine(UpToDate::Always, [] { return UpToDate::True; }));
-
-  ASSERT_EQ(UpToDate::Always, combine(UpToDate::Always, [] { return UpToDate::Always; }));
-}
-
-TEST(IdmapTestUpToDate, FromBool) {
-  ASSERT_EQ(UpToDate::False, fromBool(false));
-  ASSERT_EQ(UpToDate::True, fromBool(true));
+  ASSERT_FALSE(apk_assets->IsUpToDate());
 }
 
 }  // namespace