diff options
Diffstat (limited to 'libs/androidfw/AssetManager2.cpp')
| -rw-r--r-- | libs/androidfw/AssetManager2.cpp | 86 |
1 files changed, 67 insertions, 19 deletions
diff --git a/libs/androidfw/AssetManager2.cpp b/libs/androidfw/AssetManager2.cpp index 46f636e2ae7f..822a387351e3 100644 --- a/libs/androidfw/AssetManager2.cpp +++ b/libs/androidfw/AssetManager2.cpp @@ -23,9 +23,11 @@ #include <map> #include <set> #include <span> +#include <utility> #include "android-base/logging.h" #include "android-base/stringprintf.h" +#include "androidfw/CombinedIterator.h" #include "androidfw/ResourceTypes.h" #include "androidfw/ResourceUtils.h" #include "androidfw/Util.h" @@ -1622,6 +1624,12 @@ Theme::Theme(AssetManager2* asset_manager) : asset_manager_(asset_manager) { Theme::~Theme() = default; +static bool IsUndefined(const Res_value& value) { + // DATA_NULL_EMPTY (@empty) is a valid resource value and DATA_NULL_UNDEFINED represents + // an absence of a valid value. + return value.dataType == Res_value::TYPE_NULL && value.data != Res_value::DATA_NULL_EMPTY; +} + base::expected<std::monostate, NullOrIOError> Theme::ApplyStyle(uint32_t resid, bool force) { ATRACE_NAME("Theme::ApplyStyle"); @@ -1633,39 +1641,76 @@ base::expected<std::monostate, NullOrIOError> Theme::ApplyStyle(uint32_t resid, // Merge the flags from this style. type_spec_flags_ |= (*bag)->type_spec_flags; + // + // This function is the most expensive part of applying an frro to the existing app resources, + // and needs to be as efficient as possible. + // The data structure we're working with is two parallel sorted arrays of keys (resource IDs) + // and entries (resource value + some attributes). + // The styles get applied in sequence, starting with an empty set of attributes. Each style + // contains its values for the theme attributes, and gets applied in either normal or forced way: + // - normal way never overrides the existing attribute, so only unique style attributes are added + // - forced way overrides anything for that attribute, and if it's undefined it removes the + // previous value completely + // + // Style attributes come in a Bag data type - a sorted array of attributes with their values. This + // means we don't need to re-sort the attributes ever, and instead: + // - for an already existing attribute just skip it or apply the forced value + // - if the forced value is undefined, mark it undefined as well to get rid of it later + // - for a new attribute append it to the array, forming a new sorted section of new attributes + // past the end of the original ones (ignore undefined ones here) + // - inplace merge two sorted sections to form a single sorted array again. + // - run the last pass to remove all undefined elements + // + // Using this algorithm performs better than a repeated binary search + insert in the middle, + // as that keeps shifting the tail end of the arrays and wasting CPU cycles in memcpy(). + // + const auto starting_size = keys_.size(); + if (starting_size == 0) { + keys_.reserve((*bag)->entry_count); + entries_.reserve((*bag)->entry_count); + } + bool wrote_undefined = false; for (auto it = begin(*bag); it != end(*bag); ++it) { const uint32_t attr_res_id = it->key; - // If the resource ID passed in is not a style, the key can be some other identifier that is not // a resource ID. We should fail fast instead of operating with strange resource IDs. if (!is_valid_resid(attr_res_id)) { return base::unexpected(std::nullopt); } - - // DATA_NULL_EMPTY (@empty) is a valid resource value and DATA_NULL_UNDEFINED represents - // an absence of a valid value. - bool is_undefined = it->value.dataType == Res_value::TYPE_NULL && - it->value.data != Res_value::DATA_NULL_EMPTY; + const bool is_undefined = IsUndefined(it->value); if (!force && is_undefined) { continue; } - - const auto key_it = std::lower_bound(keys_.begin(), keys_.end(), attr_res_id); - const auto entry_it = entries_.begin() + (key_it - keys_.begin()); - if (key_it != keys_.end() && *key_it == attr_res_id) { - if (is_undefined) { - // DATA_NULL_UNDEFINED clears the value of the attribute in the theme only when `force` is - // true. - keys_.erase(key_it); - entries_.erase(entry_it); - } else if (force) { + const auto key_it = std::lower_bound(keys_.begin(), keys_.begin() + starting_size, attr_res_id); + if (key_it != keys_.begin() + starting_size && *key_it == attr_res_id) { + const auto entry_it = entries_.begin() + (key_it - keys_.begin()); + if (force || IsUndefined(entry_it->value)) { *entry_it = Entry{it->cookie, (*bag)->type_spec_flags, it->value}; + wrote_undefined |= is_undefined; } - } else { - keys_.insert(key_it, attr_res_id); - entries_.insert(entry_it, Entry{it->cookie, (*bag)->type_spec_flags, it->value}); + } else if (!is_undefined) { + keys_.emplace_back(attr_res_id); + entries_.emplace_back(it->cookie, (*bag)->type_spec_flags, it->value); } } + + if (starting_size && keys_.size() != starting_size) { + std::inplace_merge( + CombinedIterator(keys_.begin(), entries_.begin()), + CombinedIterator(keys_.begin() + starting_size, entries_.begin() + starting_size), + CombinedIterator(keys_.end(), entries_.end())); + } + if (wrote_undefined) { + auto new_end = std::remove_if(CombinedIterator(keys_.begin(), entries_.begin()), + CombinedIterator(keys_.end(), entries_.end()), + [](const auto& pair) { return IsUndefined(pair.second.value); }); + keys_.erase(new_end.it1, keys_.end()); + entries_.erase(new_end.it2, entries_.end()); + } + if (android::base::kEnableDChecks && !std::is_sorted(keys_.begin(), keys_.end())) { + ALOGW("Bag %u was unsorted in the apk?", unsigned(resid)); + return base::unexpected(std::nullopt); + } return {}; } @@ -1691,6 +1736,9 @@ std::optional<AssetManager2::SelectedValue> Theme::GetAttribute(uint32_t resid) return std::nullopt; } const auto entry_it = entries_.begin() + (key_it - keys_.begin()); + if (IsUndefined(entry_it->value)) { + return std::nullopt; + } type_spec_flags |= entry_it->type_spec_flags; if (entry_it->value.dataType == Res_value::TYPE_ATTRIBUTE) { resid = entry_it->value.data; |