New implementation of AssetManager/ResTable
The multiwindow model and Resources-per-activity
model that came in N puts greater demands on AssetManagers.
They are created whenever window dimensions change, which
can be frequently. There is a need to be able to cheaply
create a new AssetManager for each Activity, which shares
a lot of underlying state.
In order to make the creation of AssetManagers cheap,
we need a new implementation of the native AssetManager
and ResTable to support immutable representations of
APKs. This new data structure/class is ApkAssets.
ApkAssets have the same functionality of an AssetManager, except
that they operate on a single APK, and they do not do any caching.
Once loaded, they are immutable.
ApkAssets will be exposed as a Java object, with its implementation in
native code. The existing Java StringBlock will be owned by ApkAssets,
which means that Strings can be shared across AssetManagers.
ApkAssets can be cached by the ResourcesManager. Creating an AssetManager
requires only a list of ApkAssets and a configuration.
AssetManager2 (named with the suffix '2' for now while transitioning
to the new implementation) caches bags that are accessed.
Since ApkAssets are expected to be kept around longer, they do more validation
of the resource table, which cause slower load times. Measured on an angler-userdebug,
loading the framework assets takes 11ms with ApkAssets, and 2ms with the old
AssetManager implementation.
The tradeoff is that there does not need to be any security checks once an ApkAssets
is loaded, and regular resource retrieval is faster. Measured on an angler-userdebug,
accessing resource (android:string/ok) with many locales takes 18us with AssetManager2,
and 19us with AssetManager (this is per resource, so these add up).
Test: make libandroidfw_tests
Change-Id: Id0e57ee828f17008891fe3741935a9be8830b01d
diff --git a/libs/androidfw/AssetManager2.cpp b/libs/androidfw/AssetManager2.cpp
new file mode 100644
index 0000000..8d65925
--- /dev/null
+++ b/libs/androidfw/AssetManager2.cpp
@@ -0,0 +1,576 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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
+ *
+ * http://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.
+ */
+
+#define ATRACE_TAG ATRACE_TAG_RESOURCES
+
+#include "androidfw/AssetManager2.h"
+
+#include "android-base/logging.h"
+#include "android-base/stringprintf.h"
+#include "utils/ByteOrder.h"
+#include "utils/Trace.h"
+
+#ifdef _WIN32
+#ifdef ERROR
+#undef ERROR
+#endif
+#endif
+
+namespace android {
+
+AssetManager2::AssetManager2() { memset(&configuration_, 0, sizeof(configuration_)); }
+
+bool AssetManager2::SetApkAssets(const std::vector<const ApkAssets*>& apk_assets,
+ bool invalidate_caches) {
+ apk_assets_ = apk_assets;
+ if (invalidate_caches) {
+ InvalidateCaches(static_cast<uint32_t>(-1));
+ }
+ return true;
+}
+
+const std::vector<const ApkAssets*> AssetManager2::GetApkAssets() const { return apk_assets_; }
+
+const ResStringPool* AssetManager2::GetStringPoolForCookie(ApkAssetsCookie cookie) const {
+ if (cookie < 0 || static_cast<size_t>(cookie) >= apk_assets_.size()) {
+ return nullptr;
+ }
+ return apk_assets_[cookie]->GetLoadedArsc()->GetStringPool();
+}
+
+void AssetManager2::SetConfiguration(const ResTable_config& configuration) {
+ const int diff = configuration_.diff(configuration);
+ configuration_ = configuration;
+
+ if (diff) {
+ InvalidateCaches(static_cast<uint32_t>(diff));
+ }
+}
+
+const ResTable_config& AssetManager2::GetConfiguration() const { return configuration_; }
+
+std::unique_ptr<Asset> AssetManager2::Open(const std::string& filename, Asset::AccessMode mode) {
+ const std::string new_path = "assets/" + filename;
+ return OpenNonAsset(new_path, mode);
+}
+
+std::unique_ptr<Asset> AssetManager2::Open(const std::string& filename, ApkAssetsCookie cookie,
+ Asset::AccessMode mode) {
+ const std::string new_path = "assets/" + filename;
+ return OpenNonAsset(new_path, cookie, mode);
+}
+
+// Search in reverse because that's how we used to do it and we need to preserve behaviour.
+// This is unfortunate, because ClassLoaders delegate to the parent first, so the order
+// is inconsistent for split APKs.
+std::unique_ptr<Asset> AssetManager2::OpenNonAsset(const std::string& filename,
+ Asset::AccessMode mode,
+ ApkAssetsCookie* out_cookie) {
+ ATRACE_CALL();
+ for (int32_t i = apk_assets_.size() - 1; i >= 0; i--) {
+ std::unique_ptr<Asset> asset = apk_assets_[i]->Open(filename, mode);
+ if (asset) {
+ if (out_cookie != nullptr) {
+ *out_cookie = i;
+ }
+ return asset;
+ }
+ }
+
+ if (out_cookie != nullptr) {
+ *out_cookie = kInvalidCookie;
+ }
+ return {};
+}
+
+std::unique_ptr<Asset> AssetManager2::OpenNonAsset(const std::string& filename,
+ ApkAssetsCookie cookie, Asset::AccessMode mode) {
+ ATRACE_CALL();
+ if (cookie < 0 || static_cast<size_t>(cookie) >= apk_assets_.size()) {
+ return {};
+ }
+ return apk_assets_[cookie]->Open(filename, mode);
+}
+
+ApkAssetsCookie AssetManager2::FindEntry(uint32_t resid, uint16_t density_override,
+ bool stop_at_first_match, LoadedArsc::Entry* out_entry,
+ ResTable_config* out_selected_config,
+ uint32_t* out_flags) {
+ ATRACE_CALL();
+
+ // Might use this if density_override != 0.
+ ResTable_config density_override_config;
+
+ // Select our configuration or generate a density override configuration.
+ ResTable_config* desired_config = &configuration_;
+ if (density_override != 0 && density_override != configuration_.density) {
+ density_override_config = configuration_;
+ density_override_config.density = density_override;
+ desired_config = &density_override_config;
+ }
+
+ LoadedArsc::Entry best_entry;
+ ResTable_config best_config;
+ int32_t best_index = -1;
+ uint32_t cumulated_flags = 0;
+
+ const size_t apk_asset_count = apk_assets_.size();
+ for (size_t i = 0; i < apk_asset_count; i++) {
+ const LoadedArsc* loaded_arsc = apk_assets_[i]->GetLoadedArsc();
+
+ LoadedArsc::Entry current_entry;
+ ResTable_config current_config;
+ uint32_t flags = 0;
+ if (!loaded_arsc->FindEntry(resid, *desired_config, ¤t_entry, ¤t_config, &flags)) {
+ continue;
+ }
+
+ cumulated_flags |= flags;
+
+ if (best_index == -1 || current_config.isBetterThan(best_config, desired_config)) {
+ best_entry = current_entry;
+ best_config = current_config;
+ best_index = static_cast<int32_t>(i);
+ if (stop_at_first_match) {
+ break;
+ }
+ }
+ }
+
+ if (best_index == -1) {
+ return kInvalidCookie;
+ }
+
+ *out_entry = best_entry;
+ *out_selected_config = best_config;
+ *out_flags = cumulated_flags;
+ return best_index;
+}
+
+bool AssetManager2::GetResourceName(uint32_t resid, ResourceName* out_name) {
+ ATRACE_CALL();
+
+ LoadedArsc::Entry entry;
+ ResTable_config config;
+ uint32_t flags = 0u;
+ ApkAssetsCookie cookie = FindEntry(resid, 0u /* density_override */,
+ true /* stop_at_first_match */, &entry, &config, &flags);
+ if (cookie == kInvalidCookie) {
+ return false;
+ }
+
+ const std::string* package_name =
+ apk_assets_[cookie]->GetLoadedArsc()->GetPackageNameForId(resid);
+ if (package_name == nullptr) {
+ return false;
+ }
+
+ out_name->package = package_name->data();
+ out_name->package_len = package_name->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;
+}
+
+bool AssetManager2::GetResourceFlags(uint32_t resid, uint32_t* out_flags) {
+ LoadedArsc::Entry entry;
+ ResTable_config config;
+ ApkAssetsCookie cookie = FindEntry(resid, 0u /* density_override */,
+ false /* stop_at_first_match */, &entry, &config, out_flags);
+ return cookie != kInvalidCookie;
+}
+
+ApkAssetsCookie AssetManager2::GetResource(uint32_t resid, bool may_be_bag,
+ uint16_t density_override, Res_value* out_value,
+ ResTable_config* out_selected_config,
+ uint32_t* out_flags) {
+ ATRACE_CALL();
+
+ LoadedArsc::Entry entry;
+ ResTable_config config;
+ uint32_t flags = 0u;
+ ApkAssetsCookie cookie =
+ FindEntry(resid, density_override, false /* stop_at_first_match */, &entry, &config, &flags);
+ if (cookie == kInvalidCookie) {
+ return kInvalidCookie;
+ }
+
+ if (dtohl(entry.entry->flags) & ResTable_entry::FLAG_COMPLEX) {
+ if (!may_be_bag) {
+ LOG(ERROR) << base::StringPrintf("Resource %08x is a complex map type.", resid);
+ }
+ return kInvalidCookie;
+ }
+
+ const Res_value* device_value = reinterpret_cast<const Res_value*>(
+ reinterpret_cast<const uint8_t*>(entry.entry) + dtohs(entry.entry->size));
+ out_value->copyFrom_dtoh(*device_value);
+ *out_selected_config = config;
+ *out_flags = flags;
+ return cookie;
+}
+
+const ResolvedBag* AssetManager2::GetBag(uint32_t resid) {
+ ATRACE_CALL();
+
+ auto cached_iter = cached_bags_.find(resid);
+ if (cached_iter != cached_bags_.end()) {
+ return cached_iter->second.get();
+ }
+
+ LoadedArsc::Entry entry;
+ ResTable_config config;
+ uint32_t flags = 0u;
+ ApkAssetsCookie cookie = FindEntry(resid, 0u /* density_override */,
+ false /* stop_at_first_match */, &entry, &config, &flags);
+ if (cookie == kInvalidCookie) {
+ return nullptr;
+ }
+
+ // Check that the size of the entry header is at least as big as
+ // the desired ResTable_map_entry. Also verify that the entry
+ // was intended to be a map.
+ if (dtohs(entry.entry->size) < sizeof(ResTable_map_entry) ||
+ (dtohs(entry.entry->flags) & ResTable_entry::FLAG_COMPLEX) == 0) {
+ // Not a bag, nothing to do.
+ return nullptr;
+ }
+
+ const ResTable_map_entry* map = reinterpret_cast<const ResTable_map_entry*>(entry.entry);
+ const ResTable_map* map_entry =
+ reinterpret_cast<const ResTable_map*>(reinterpret_cast<const uint8_t*>(map) + map->size);
+ const ResTable_map* const map_entry_end = map_entry + dtohl(map->count);
+
+ const uint32_t parent = dtohl(map->parent.ident);
+ if (parent == 0) {
+ // There is no parent, meaning there is nothing to inherit and we can do a simple
+ // copy of the entries in the map.
+ const size_t entry_count = map_entry_end - map_entry;
+ util::unique_cptr<ResolvedBag> new_bag{reinterpret_cast<ResolvedBag*>(
+ malloc(sizeof(ResolvedBag) + (entry_count * sizeof(ResolvedBag::Entry))))};
+ ResolvedBag::Entry* new_entry = new_bag->entries;
+ for (; map_entry != map_entry_end; ++map_entry) {
+ new_entry->cookie = cookie;
+ new_entry->value.copyFrom_dtoh(map_entry->value);
+ new_entry->key = dtohl(map_entry->name.ident);
+ new_entry->key_pool = nullptr;
+ new_entry->type_pool = nullptr;
+ ++new_entry;
+ }
+ new_bag->type_spec_flags = flags;
+ new_bag->entry_count = static_cast<uint32_t>(entry_count);
+ ResolvedBag* result = new_bag.get();
+ cached_bags_[resid] = std::move(new_bag);
+ return result;
+ }
+
+ // Get the parent and do a merge of the keys.
+ const ResolvedBag* parent_bag = GetBag(parent);
+ if (parent_bag == nullptr) {
+ // Failed to get the parent that should exist.
+ return nullptr;
+ }
+
+ // Combine flags from the parent and our own bag.
+ flags |= parent_bag->type_spec_flags;
+
+ // Create the max possible entries we can make. Once we construct the bag,
+ // we will realloc to fit to size.
+ const size_t max_count = parent_bag->entry_count + dtohl(map->count);
+ ResolvedBag* new_bag = reinterpret_cast<ResolvedBag*>(
+ malloc(sizeof(ResolvedBag) + (max_count * sizeof(ResolvedBag::Entry))));
+ ResolvedBag::Entry* new_entry = new_bag->entries;
+
+ const ResolvedBag::Entry* parent_entry = parent_bag->entries;
+ const ResolvedBag::Entry* const parent_entry_end = parent_entry + parent_bag->entry_count;
+
+ // The keys are expected to be in sorted order. Merge the two bags.
+ while (map_entry != map_entry_end && parent_entry != parent_entry_end) {
+ const uint32_t child_key = dtohl(map_entry->name.ident);
+ if (child_key <= parent_entry->key) {
+ // Use the child key if it comes before the parent
+ // or is equal to the parent (overrides).
+ new_entry->cookie = cookie;
+ new_entry->value.copyFrom_dtoh(map_entry->value);
+ new_entry->key = child_key;
+ new_entry->key_pool = nullptr;
+ new_entry->type_pool = nullptr;
+ ++map_entry;
+ } else {
+ // Take the parent entry as-is.
+ memcpy(new_entry, parent_entry, sizeof(*new_entry));
+ }
+
+ if (child_key >= parent_entry->key) {
+ // Move to the next parent entry if we used it or it was overridden.
+ ++parent_entry;
+ }
+ // Increment to the next entry to fill.
+ ++new_entry;
+ }
+
+ // Finish the child entries if they exist.
+ while (map_entry != map_entry_end) {
+ new_entry->cookie = cookie;
+ new_entry->value.copyFrom_dtoh(map_entry->value);
+ new_entry->key = dtohl(map_entry->name.ident);
+ new_entry->key_pool = nullptr;
+ new_entry->type_pool = nullptr;
+ ++map_entry;
+ ++new_entry;
+ }
+
+ // Finish the parent entries if they exist.
+ if (parent_entry != parent_entry_end) {
+ // Take the rest of the parent entries as-is.
+ const size_t num_entries_to_copy = parent_entry_end - parent_entry;
+ memcpy(new_entry, parent_entry, num_entries_to_copy * sizeof(*new_entry));
+ new_entry += num_entries_to_copy;
+ }
+
+ // Resize the resulting array to fit.
+ const size_t actual_count = new_entry - new_bag->entries;
+ if (actual_count != max_count) {
+ new_bag = reinterpret_cast<ResolvedBag*>(
+ realloc(new_bag, sizeof(ResolvedBag) + (actual_count * sizeof(ResolvedBag::Entry))));
+ }
+
+ util::unique_cptr<ResolvedBag> final_bag{new_bag};
+ final_bag->type_spec_flags = flags;
+ final_bag->entry_count = static_cast<uint32_t>(actual_count);
+ ResolvedBag* result = final_bag.get();
+ cached_bags_[resid] = std::move(final_bag);
+ return result;
+}
+
+void AssetManager2::InvalidateCaches(uint32_t diff) {
+ if (diff == 0xffffffffu) {
+ // Everything must go.
+ cached_bags_.clear();
+ return;
+ }
+
+ // Be more conservative with what gets purged. Only if the bag has other possible
+ // variations with respect to what changed (diff) should we remove it.
+ for (auto iter = cached_bags_.cbegin(); iter != cached_bags_.cend();) {
+ if (diff & iter->second->type_spec_flags) {
+ iter = cached_bags_.erase(iter);
+ } else {
+ ++iter;
+ }
+ }
+}
+
+std::unique_ptr<Theme> AssetManager2::NewTheme() { return std::unique_ptr<Theme>(new Theme(this)); }
+
+bool Theme::ApplyStyle(uint32_t resid, bool force) {
+ ATRACE_CALL();
+
+ const ResolvedBag* bag = asset_manager_->GetBag(resid);
+ if (bag == nullptr) {
+ return false;
+ }
+
+ // Merge the flags from this style.
+ type_spec_flags_ |= bag->type_spec_flags;
+
+ // On the first iteration, verify the attribute IDs and
+ // update the entry count in each type.
+ const auto bag_iter_end = end(bag);
+ for (auto bag_iter = begin(bag); bag_iter != bag_iter_end; ++bag_iter) {
+ const uint32_t attr_resid = bag_iter->key;
+
+ // If the resource ID passed in is not a style, the key can be
+ // some other identifier that is not a resource ID.
+ if (!util::is_valid_resid(attr_resid)) {
+ return false;
+ }
+
+ const uint32_t package_idx = util::get_package_id(attr_resid);
+
+ // The type ID is 1-based, so subtract 1 to get an index.
+ const uint32_t type_idx = util::get_type_id(attr_resid) - 1;
+ const uint32_t entry_idx = util::get_entry_id(attr_resid);
+
+ std::unique_ptr<Package>& package = packages_[package_idx];
+ if (package == nullptr) {
+ package.reset(new Package());
+ }
+
+ util::unique_cptr<Type>& type = package->types[type_idx];
+ if (type == nullptr) {
+ // Set the initial capacity to take up a total amount of 1024 bytes.
+ constexpr uint32_t kInitialCapacity = (1024u - sizeof(Type)) / sizeof(Entry);
+ const uint32_t initial_capacity = std::max(entry_idx, kInitialCapacity);
+ type.reset(
+ reinterpret_cast<Type*>(calloc(sizeof(Type) + (initial_capacity * sizeof(Entry)), 1)));
+ type->entry_capacity = initial_capacity;
+ }
+
+ // Set the entry_count to include this entry. We will populate
+ // and resize the array as necessary in the next pass.
+ if (entry_idx + 1 > type->entry_count) {
+ // Increase the entry count to include this.
+ type->entry_count = entry_idx + 1;
+ }
+ }
+
+ // On the second pass, we will realloc to fit the entry counts
+ // and populate the structures.
+ for (auto bag_iter = begin(bag); bag_iter != bag_iter_end; ++bag_iter) {
+ const uint32_t attr_resid = bag_iter->key;
+ const uint32_t package_idx = util::get_package_id(attr_resid);
+ const uint32_t type_idx = util::get_type_id(attr_resid) - 1;
+ const uint32_t entry_idx = util::get_entry_id(attr_resid);
+ Package* package = packages_[package_idx].get();
+ util::unique_cptr<Type>& type = package->types[type_idx];
+ if (type->entry_count != type->entry_capacity) {
+ // Resize to fit the actual entries that will be included.
+ Type* type_ptr = type.release();
+ type.reset(reinterpret_cast<Type*>(
+ realloc(type_ptr, sizeof(Type) + (type_ptr->entry_count * sizeof(Entry)))));
+ if (type->entry_capacity < type->entry_count) {
+ // Clear the newly allocated memory (which does not get zero initialized).
+ // We need to do this because we |= type_spec_flags.
+ memset(type->entries + type->entry_capacity, 0,
+ sizeof(Entry) * (type->entry_count - type->entry_capacity));
+ }
+ type->entry_capacity = type->entry_count;
+ }
+ Entry& entry = type->entries[entry_idx];
+ if (force || entry.value.dataType == Res_value::TYPE_NULL) {
+ entry.cookie = bag_iter->cookie;
+ entry.type_spec_flags |= bag->type_spec_flags;
+ entry.value = bag_iter->value;
+ }
+ }
+ return true;
+}
+
+ApkAssetsCookie Theme::GetAttribute(uint32_t resid, Res_value* out_value,
+ uint32_t* out_flags) const {
+ constexpr const int kMaxIterations = 20;
+
+ uint32_t type_spec_flags = 0u;
+
+ for (int iterations_left = kMaxIterations; iterations_left > 0; iterations_left--) {
+ if (!util::is_valid_resid(resid)) {
+ return kInvalidCookie;
+ }
+
+ const uint32_t package_idx = util::get_package_id(resid);
+
+ // Type ID is 1-based, subtract 1 to get the index.
+ const uint32_t type_idx = util::get_type_id(resid) - 1;
+ const uint32_t entry_idx = util::get_entry_id(resid);
+
+ const Package* package = packages_[package_idx].get();
+ if (package == nullptr) {
+ return kInvalidCookie;
+ }
+
+ const Type* type = package->types[type_idx].get();
+ if (type == nullptr) {
+ return kInvalidCookie;
+ }
+
+ if (entry_idx >= type->entry_count) {
+ return kInvalidCookie;
+ }
+
+ const Entry& entry = type->entries[entry_idx];
+ type_spec_flags |= entry.type_spec_flags;
+
+ switch (entry.value.dataType) {
+ case Res_value::TYPE_ATTRIBUTE:
+ resid = entry.value.data;
+ break;
+
+ case Res_value::TYPE_NULL:
+ return kInvalidCookie;
+
+ default:
+ *out_value = entry.value;
+ if (out_flags != nullptr) {
+ *out_flags = type_spec_flags;
+ }
+ return entry.cookie;
+ }
+ }
+
+ LOG(WARNING) << base::StringPrintf("Too many (%d) attribute references, stopped at: 0x%08x",
+ kMaxIterations, resid);
+ return kInvalidCookie;
+}
+
+void Theme::Clear() {
+ type_spec_flags_ = 0u;
+ for (std::unique_ptr<Package>& package : packages_) {
+ package.reset();
+ }
+}
+
+bool Theme::SetTo(const Theme& o) {
+ if (this == &o) {
+ return true;
+ }
+
+ if (asset_manager_ != o.asset_manager_) {
+ return false;
+ }
+
+ type_spec_flags_ = o.type_spec_flags_;
+
+ for (size_t p = 0; p < arraysize(packages_); p++) {
+ const Package* package = o.packages_[p].get();
+ if (package == nullptr) {
+ packages_[p].reset();
+ continue;
+ }
+
+ for (size_t t = 0; t < arraysize(package->types); t++) {
+ const Type* type = package->types[t].get();
+ if (type == nullptr) {
+ packages_[p]->types[t].reset();
+ continue;
+ }
+
+ const size_t type_alloc_size = sizeof(Type) + (type->entry_capacity * sizeof(Entry));
+ void* copied_data = malloc(type_alloc_size);
+ memcpy(copied_data, type, type_alloc_size);
+ packages_[p]->types[t].reset(reinterpret_cast<Type*>(copied_data));
+ }
+ }
+ return true;
+}
+
+} // namespace android