// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_BASE_RESOURCE_DATA_PACK_WITH_RESOURCE_SHARING_LACROS_H_
#define UI_BASE_RESOURCE_DATA_PACK_WITH_RESOURCE_SHARING_LACROS_H_
#include <map>
#include <memory>
#include <optional>
#include <string_view>
#include <vector>
#include "base/component_export.h"
#include "base/files/file_path.h"
#include "base/memory/raw_ptr.h"
#include "ui/base/resource/data_pack.h"
#include "ui/base/resource/resource_handle.h"
#include "ui/base/resource/resource_scale_factor.h"
#include "ui/base/resource/scoped_file_writer.h"
namespace ui {
// This class is used in lacros to reduce memory usage. The majority
// of the resources that are needed by lacros-chrome ship with ash-chrome.
// To avoid memory mapping similar (large) files (resulting in increased memory
// usage), this class shares resources with ash-chrome. Sharing is
// done by determining which resources are identical and maintaining a
// mapping file that maps from lacros-chrome resource id to ash-chrome
// resource id. Resources that are unique to lacros-chrome are placed
// in a fallback file.
//
// The mapping file is recreated as necessary.
class COMPONENT_EXPORT(UI_DATA_PACK) DataPackWithResourceSharing
: public ResourceHandle {
public:
explicit DataPackWithResourceSharing(
ResourceScaleFactor resource_scale_factor);
DataPackWithResourceSharing(const DataPackWithResourceSharing&) = delete;
DataPackWithResourceSharing& operator=(const DataPackWithResourceSharing&) =
delete;
~DataPackWithResourceSharing() override;
// Data of Lacros version and timestamp.
struct LacrosVersionData {
// The size of version components is 4. Version of Lacros. Each element
// corredponds to major, minor, build and patch of CHROME_VERSION.
static constexpr size_t kVersionComponentsSize = 4;
// Version of Lacros.
uint32_t version[kVersionComponentsSize];
// Last updated time of lacros-chrome.
int64_t timestamp;
};
// Maps resource id in Lacros resources to Ash resources.
// Data assigned to `lacros_resource_id` and `ash_resource_id` must be same.
struct Mapping {
Mapping(uint16_t lacros_resource_id, uint16_t ash_resource_id);
// Comparison function used for sorting.
static int CompareById(const void* void_key, const void* void_entry);
// `lacros_resource_id` is applicable in Lacros resources.
uint16_t lacros_resource_id;
// `ash_resource_id` is applicable in Ash resources `ash_data_pack_`.
uint16_t ash_resource_id;
};
// Loads a pack file from `shared_resource_path` with ash resources
// `ash_path`. Each resources for Lacros are included in eitehr of `ash_path`
// or `shared_resource_path`.
// Lacros resources are mpped to Ash resources if duplicated. The mapping tble
// can be obtained from `shared_resource_path`. As for Lacros resources which
// are not included in Ash resources, add them to `shared_resource_path` as
// fallback resources.
// `shared_resource_path` is expected to be already generated from lacros
// resources and ash resources. If the file was not successfully generated,
// `is_valid` in `shared_resource_path` is set to 0.
bool LoadFromPathWithAshResource(const base::FilePath& shared_resource_path,
const base::FilePath& ash_path);
// ResourceHandle implementation:
bool HasResource(uint16_t resource_id) const override;
std::optional<std::string_view> GetStringPiece(
uint16_t resource_id) const override;
base::RefCountedStaticMemory* GetStaticMemory(
uint16_t resource_id) const override;
TextEncodingType GetTextEncodingType() const override;
ResourceScaleFactor GetResourceScaleFactor() const override;
#if DCHECK_IS_ON()
// Checks to see if any resource in this DataPack already exists in the list
// of resources.
void CheckForDuplicateResources(
const std::vector<std::unique_ptr<ResourceHandle>>& handles) override;
#endif
// If either of |shared_resource_path| is not valid or doesn't exit, generate
// them from |ash_path| and |lacros_path|.
static bool MaybeGenerateFallbackAndMapping(
const base::FilePath& ash_path,
const base::FilePath& lacros_path,
const base::FilePath& shared_resource_path,
ResourceScaleFactor resource_scale_factor);
// Should only be used for unit-testing, as this is an implementation detail.
size_t GetMappingTableSizeForTesting() const { return mapping_count_; }
const Mapping* GetMappingByMappingTableIndexForTesting(size_t index) const {
return &mapping_table_[index];
}
// Generate file with specific data. Shared resource file is expected to be
// created only by MaybeGenerateFallbackAdnMapping, so DO NOT use this except
// for unit-testing.
static bool WriteSharedResourceFileForTesting(
const base::FilePath& path,
std::vector<Mapping> mapping = std::vector<Mapping>(),
std::vector<uint16_t> resource_ids = std::vector<uint16_t>(),
std::map<uint16_t, uint16_t> aliases = std::map<uint16_t, uint16_t>(),
std::map<uint16_t, std::string_view> fallback_resources =
std::map<uint16_t, std::string_view>());
private:
// Loads mapping_table_ from mapping file.
bool LoadMappingTable(const base::FilePath& path);
// Returns mapped resource ID if |resource_id| is in |mapping_table_|.
// Return null if not.
const std::optional<uint16_t> LookupMappingTable(uint16_t resource_id) const;
// Check the shared resource `path` version is valid. If Lacros version used
// to generate `path` is not the same with the current Lacros, return false.
// We consider the versions are the same iff
// 1. Lacros chrome version is same.
// 2. Last updated time of Lacros file is same.
// Here, we check not only chrome version but also the time since there might
// be a change in Lacros which affects resource file. This is mostly used by
// developers.
static bool IsSharedResourceValid(const base::FilePath& path);
// Writes a version and its updated time of Lacros used to generate file.
static bool WriteLacrosVersion(ScopedFileWriter& file);
// Writes a mapping table `mapping` to `file`.
static bool WriteMappingTable(std::vector<Mapping> mapping,
ScopedFileWriter& file);
// Writes a fallback resource table, alias table and string data to `file`.
// `margin_to_skip` represents the size of the margin in bytes before
// resouce_table information starts.
static bool WriteFallbackResources(
std::vector<uint16_t> resource_ids,
std::map<uint16_t, uint16_t> aliases,
std::map<uint16_t, std::string_view> fallback_resources,
size_t margin_to_skip,
ScopedFileWriter& file);
// Close and delete temp shared resource file used for generating.
// This should be called when failing during generating a shared resource.
static void OnFailedToGenerate(ScopedFileWriter& file,
const base::FilePath& shared_resource_path);
std::unique_ptr<DataPack::DataSource> data_source_;
// Each Mapping maps lacros resource id to ash resource id if the same data
// exists in ash resources .pak.
// Lacros resource id registered in `mapping_table_` as a key should not be
// included in fallback_data_pack_.
raw_ptr<const Mapping, AllowPtrArithmetic> mapping_table_;
size_t mapping_count_ = 0;
// Stores DataPacks of fallback resources and ash resources for each.
std::unique_ptr<DataPack> fallback_data_pack_;
std::unique_ptr<DataPack> ash_data_pack_;
// The scale of the image in this resource pack relative to images in the 1x
// resource pak.
ResourceScaleFactor resource_scale_factor_;
};
} // namespace ui
#endif // UI_BASE_RESOURCE_DATA_PACK_WITH_RESOURCE_SHARING_LACROS_H_
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