cmds/idmap2/libidmap2/Idmap.cpp - android_frameworks_base - Gitiles

 /*
  * Copyright (C) 2018 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.
  */

 #include "idmap2/Idmap.h"

 #include <algorithm>
 #include <cassert>
 #include <iostream>
 #include <iterator>
 #include <limits>
 #include <memory>
 #include <string>
 #include <utility>

 #include "android-base/macros.h"
 #include "androidfw/AssetManager2.h"
 #include "idmap2/ResourceMapping.h"
 #include "idmap2/ResourceUtils.h"
 #include "idmap2/Result.h"
 #include "idmap2/SysTrace.h"

 namespace android::idmap2 {

 namespace {

 bool WARN_UNUSED Read8(std::istream& stream, uint8_t* out) {
   uint8_t value;
   if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint8_t))) {
     *out = value;
     return true;
   }
   return false;
 }

 bool WARN_UNUSED Read16(std::istream& stream, uint16_t* out) {
   uint16_t value;
   if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint16_t))) {
     *out = dtohs(value);
     return true;
   }
   return false;
 }

 bool WARN_UNUSED Read32(std::istream& stream, uint32_t* out) {
   uint32_t value;
   if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint32_t))) {
     *out = dtohl(value);
     return true;
   }
   return false;
 }

 bool WARN_UNUSED ReadString(std::istream& stream, std::string* out) {
   uint32_t size;
   if (!Read32(stream, &size)) {
     return false;
   }
   if (size == 0) {
     *out = "";
     return true;
   }
   std::string buf(size, '\0');
   if (!stream.read(buf.data(), size)) {
     return false;
   }
   uint32_t padding_size = CalculatePadding(size);
   if (padding_size != 0 && !stream.seekg(padding_size, std::ios_base::cur)) {
     return false;
   }
   *out = buf;
   return true;
 }

 }  // namespace

 std::unique_ptr<const IdmapHeader> IdmapHeader::FromBinaryStream(std::istream& stream) {
   std::unique_ptr<IdmapHeader> idmap_header(new IdmapHeader());
   if (!Read32(stream, &idmap_header->magic_) || !Read32(stream, &idmap_header->version_)) {
     return nullptr;
   }

   if (idmap_header->magic_ != kIdmapMagic || idmap_header->version_ != kIdmapCurrentVersion) {
     // Do not continue parsing if the file is not a current version idmap.
     return nullptr;
   }

   uint32_t enforce_overlayable;
   if (!Read32(stream, &idmap_header->target_crc_) || !Read32(stream, &idmap_header->overlay_crc_) ||
       !Read32(stream, &idmap_header->fulfilled_policies_) ||
       !Read32(stream, &enforce_overlayable) || !ReadString(stream, &idmap_header->target_path_) ||
       !ReadString(stream, &idmap_header->overlay_path_) ||
       !ReadString(stream, &idmap_header->overlay_name_) ||
       !ReadString(stream, &idmap_header->debug_info_)) {
     return nullptr;
   }

   idmap_header->enforce_overlayable_ = enforce_overlayable != 0U;
   return std::move(idmap_header);
 }

 Result<Unit> IdmapHeader::IsUpToDate(const TargetResourceContainer& target,
                                      const OverlayResourceContainer& overlay,
                                      const std::string& overlay_name,
                                      PolicyBitmask fulfilled_policies,
                                      bool enforce_overlayable) const {
   const Result<uint32_t> target_crc = target.GetCrc();
   if (!target_crc) {
     return Error("failed to get target crc");
   }

   const Result<uint32_t> overlay_crc = overlay.GetCrc();
   if (!overlay_crc) {
     return Error("failed to get overlay crc");
   }

   return IsUpToDate(target.GetPath(), overlay.GetPath(), overlay_name, *target_crc, *overlay_crc,
                     fulfilled_policies, enforce_overlayable);
 }

 Result<Unit> IdmapHeader::IsUpToDate(const std::string& target_path,
                                      const std::string& overlay_path,
                                      const std::string& overlay_name, uint32_t target_crc,
                                      uint32_t overlay_crc, PolicyBitmask fulfilled_policies,
                                      bool enforce_overlayable) const {
   if (magic_ != kIdmapMagic) {
     return Error("bad magic: actual 0x%08x, expected 0x%08x", magic_, kIdmapMagic);
   }

   if (version_ != kIdmapCurrentVersion) {
     return Error("bad version: actual 0x%08x, expected 0x%08x", version_, kIdmapCurrentVersion);
   }

   if (target_crc_ != target_crc) {
     return Error("bad target crc: idmap version 0x%08x, file system version 0x%08x", target_crc_,
                  target_crc);
   }

   if (overlay_crc_ != overlay_crc) {
     return Error("bad overlay crc: idmap version 0x%08x, file system version 0x%08x", overlay_crc_,
                  overlay_crc);
   }

   if (fulfilled_policies_ != fulfilled_policies) {
     return Error("bad fulfilled policies: idmap version 0x%08x, file system version 0x%08x",
                  fulfilled_policies, fulfilled_policies_);
   }

   if (enforce_overlayable != enforce_overlayable_) {
     return Error("bad enforce overlayable: idmap version %s, file system version %s",
                  enforce_overlayable ? "true" : "false", enforce_overlayable_ ? "true" : "false");
   }

   if (target_path != target_path_) {
     return Error("bad target path: idmap version %s, file system version %s", target_path.c_str(),
                  target_path_.c_str());
   }

   if (overlay_path != overlay_path_) {
     return Error("bad overlay path: idmap version %s, file system version %s", overlay_path.c_str(),
                  overlay_path_.c_str());
   }

   if (overlay_name != overlay_name_) {
     return Error("bad overlay name: idmap version %s, file system version %s", overlay_name.c_str(),
                  overlay_name_.c_str());
   }

   return Unit{};
 }

 std::unique_ptr<const IdmapData::Header> IdmapData::Header::FromBinaryStream(std::istream& stream) {
   std::unique_ptr<IdmapData::Header> idmap_data_header(new IdmapData::Header());
   if (!Read32(stream, &idmap_data_header->target_entry_count) ||
       !Read32(stream, &idmap_data_header->target_entry_inline_count) ||
       !Read32(stream, &idmap_data_header->target_entry_inline_value_count) ||
       !Read32(stream, &idmap_data_header->config_count) ||
       !Read32(stream, &idmap_data_header->overlay_entry_count) ||
       !Read32(stream, &idmap_data_header->string_pool_index_offset)) {
     return nullptr;
   }

   return std::move(idmap_data_header);
 }

 std::unique_ptr<const IdmapData> IdmapData::FromBinaryStream(std::istream& stream) {
   std::unique_ptr<IdmapData> data(new IdmapData());
   data->header_ = IdmapData::Header::FromBinaryStream(stream);
   if (!data->header_) {
     return nullptr;
   }

   // Read the mapping of target resource id to overlay resource value.
   for (size_t i = 0; i < data->header_->GetTargetEntryCount(); i++) {
     TargetEntry target_entry{};
     if (!Read32(stream, &target_entry.target_id) || !Read32(stream, &target_entry.overlay_id)) {
       return nullptr;
     }
     data->target_entries_.emplace_back(target_entry);
   }

   // Read the mapping of target resource id to inline overlay values.
   std::vector<std::tuple<TargetInlineEntry, uint32_t, uint32_t>> target_inline_entries;
   for (size_t i = 0; i < data->header_->GetTargetInlineEntryCount(); i++) {
     TargetInlineEntry target_entry{};
     uint32_t entry_offset;
     uint32_t entry_count;
     if (!Read32(stream, &target_entry.target_id) || !Read32(stream, &entry_offset)
         || !Read32(stream, &entry_count)) {
       return nullptr;
     }
     target_inline_entries.emplace_back(target_entry, entry_offset, entry_count);
   }

   // Read the inline overlay resource values
   std::vector<std::pair<uint32_t, TargetValue>> target_values;
   uint8_t unused1;
   uint16_t unused2;
   for (size_t i = 0; i < data->header_->GetTargetInlineEntryValueCount(); i++) {
     uint32_t config_index;
     if (!Read32(stream, &config_index)) {
       return nullptr;
     }
     TargetValue value;
     if (!Read16(stream, &unused2)
         || !Read8(stream, &unused1)
         || !Read8(stream, &value.data_type)
         || !Read32(stream, &value.data_value)) {
       return nullptr;
     }
     target_values.emplace_back(config_index, value);
   }

   // Read the configurations
   std::vector<ConfigDescription> configurations;
   for (size_t i = 0; i < data->header_->GetConfigCount(); i++) {
     ConfigDescription cd;
     if (!stream.read(reinterpret_cast<char*>(&cd), sizeof(ConfigDescription))) {
       return nullptr;
     }
     configurations.emplace_back(cd);
   }

   // Construct complete target inline entries
   for (auto [target_entry, entry_offset, entry_count] : target_inline_entries) {
     for(size_t i = 0; i < entry_count; i++) {
       const auto& target_value = target_values[entry_offset + i];
       const auto& config = configurations[target_value.first];
       target_entry.values[config] = target_value.second;
     }
     data->target_inline_entries_.emplace_back(target_entry);
   }

   // Read the mapping of overlay resource id to target resource id.
   for (size_t i = 0; i < data->header_->GetOverlayEntryCount(); i++) {
     OverlayEntry overlay_entry{};
     if (!Read32(stream, &overlay_entry.overlay_id) || !Read32(stream, &overlay_entry.target_id)) {
       return nullptr;
     }
     data->overlay_entries_.emplace_back(overlay_entry);
   }

   // Read raw string pool bytes.
   if (!ReadString(stream, &data->string_pool_data_)) {
     return nullptr;
   }
   return std::move(data);
 }

 std::string Idmap::CanonicalIdmapPathFor(const std::string& absolute_dir,
                                          const std::string& absolute_apk_path) {
   assert(absolute_dir.size() > 0 && absolute_dir[0] == "/");
   assert(absolute_apk_path.size() > 0 && absolute_apk_path[0] == "/");
   std::string copy(++absolute_apk_path.cbegin(), absolute_apk_path.cend());
   replace(copy.begin(), copy.end(), '/', '@');
   return absolute_dir + "/" + copy + "@idmap";
 }

 Result<std::unique_ptr<const Idmap>> Idmap::FromBinaryStream(std::istream& stream) {
   SYSTRACE << "Idmap::FromBinaryStream";
   std::unique_ptr<Idmap> idmap(new Idmap());

   idmap->header_ = IdmapHeader::FromBinaryStream(stream);
   if (!idmap->header_) {
     return Error("failed to parse idmap header");
   }

   // idmap version 0x01 does not specify the number of data blocks that follow
   // the idmap header; assume exactly one data block
   for (int i = 0; i < 1; i++) {
     std::unique_ptr<const IdmapData> data = IdmapData::FromBinaryStream(stream);
     if (!data) {
       return Error("failed to parse data block %d", i);
     }
     idmap->data_.push_back(std::move(data));
   }

   return {std::move(idmap)};
 }

 Result<std::unique_ptr<const IdmapData>> IdmapData::FromResourceMapping(
     const ResourceMapping& resource_mapping) {
   if (resource_mapping.GetTargetToOverlayMap().empty()) {
     return Error("no resources were overlaid");
   }

   std::unique_ptr<IdmapData> data(new IdmapData());
   data->string_pool_data_ = std::string(resource_mapping.GetStringPoolData());
   uint32_t inline_value_count = 0;
   std::set<std::string> config_set;
   for (const auto& mapping : resource_mapping.GetTargetToOverlayMap()) {
     if (auto overlay_resource = std::get_if<ResourceId>(&mapping.second)) {
       data->target_entries_.push_back({mapping.first, *overlay_resource});
     } else {
       std::map<ConfigDescription, TargetValue> values;
       for (const auto& [config, value] : std::get<ConfigMap>(mapping.second)) {
         config_set.insert(config);
         ConfigDescription cd;
         ConfigDescription::Parse(config, &cd);
         values[cd] = value;
         inline_value_count++;
       }
       data->target_inline_entries_.push_back({mapping.first, values});
     }
   }

   for (const auto& mapping : resource_mapping.GetOverlayToTargetMap()) {
     data->overlay_entries_.emplace_back(IdmapData::OverlayEntry{mapping.first, mapping.second});
   }

   std::unique_ptr<IdmapData::Header> data_header(new IdmapData::Header());
   data_header->target_entry_count = static_cast<uint32_t>(data->target_entries_.size());
   data_header->target_entry_inline_count =
       static_cast<uint32_t>(data->target_inline_entries_.size());
   data_header->target_entry_inline_value_count = inline_value_count;
   data_header->config_count = config_set.size();
   data_header->overlay_entry_count = static_cast<uint32_t>(data->overlay_entries_.size());
   data_header->string_pool_index_offset = resource_mapping.GetStringPoolOffset();
   data->header_ = std::move(data_header);
   return {std::move(data)};
 }

 Result<std::unique_ptr<const Idmap>> Idmap::FromContainers(const TargetResourceContainer& target,
                                                            const OverlayResourceContainer& overlay,
                                                            const std::string& overlay_name,
                                                            const PolicyBitmask& fulfilled_policies,
                                                            bool enforce_overlayable) {
   SYSTRACE << "Idmap::FromApkAssets";
   std::unique_ptr<IdmapHeader> header(new IdmapHeader());
   header->magic_ = kIdmapMagic;
   header->version_ = kIdmapCurrentVersion;

   const auto target_crc = target.GetCrc();
   if (!target_crc) {
     return Error(target_crc.GetError(), "failed to get zip CRC for '%s'", target.GetPath().data());
   }
   header->target_crc_ = *target_crc;

   const auto overlay_crc = overlay.GetCrc();
   if (!overlay_crc) {
     return Error(overlay_crc.GetError(), "failed to get zip CRC for '%s'",
                  overlay.GetPath().data());
   }
   header->overlay_crc_ = *overlay_crc;

   header->fulfilled_policies_ = fulfilled_policies;
   header->enforce_overlayable_ = enforce_overlayable;
   header->target_path_ = target.GetPath();
   header->overlay_path_ = overlay.GetPath();
   header->overlay_name_ = overlay_name;

   auto info = overlay.FindOverlayInfo(overlay_name);
   if (!info) {
     return Error(info.GetError(), "failed to get overlay info for '%s'", overlay.GetPath().data());
   }

   LogInfo log_info;
   auto resource_mapping = ResourceMapping::FromContainers(
       target, overlay, *info, fulfilled_policies, enforce_overlayable, log_info);
   if (!resource_mapping) {
     return Error(resource_mapping.GetError(), "failed to generate resource map for '%s'",
                  overlay.GetPath().data());
   }

   auto idmap_data = IdmapData::FromResourceMapping(*resource_mapping);
   if (!idmap_data) {
     return idmap_data.GetError();
   }

   std::unique_ptr<Idmap> idmap(new Idmap());
   header->debug_info_ = log_info.GetString();
   idmap->header_ = std::move(header);
   idmap->data_.push_back(std::move(*idmap_data));

   return {std::move(idmap)};
 }

 void IdmapHeader::accept(Visitor* v) const {
   assert(v != nullptr);
   v->visit(*this);
 }

 void IdmapData::Header::accept(Visitor* v) const {
   assert(v != nullptr);
   v->visit(*this);
 }

 void IdmapData::accept(Visitor* v) const {
   assert(v != nullptr);
   header_->accept(v);
   v->visit(*this);
 }

 void Idmap::accept(Visitor* v) const {
   assert(v != nullptr);
   header_->accept(v);
   v->visit(*this);
   auto end = data_.cend();
   for (auto iter = data_.cbegin(); iter != end; ++iter) {
     (*iter)->accept(v);
   }
 }

 }  // namespace android::idmap2
	/*
	* Copyright (C) 2018 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.
	*/

	#include "idmap2/Idmap.h"

	#include <algorithm>
	#include <cassert>
	#include <iostream>
	#include <iterator>
	#include <limits>
	#include <memory>
	#include <string>
	#include <utility>

	#include "android-base/macros.h"
	#include "androidfw/AssetManager2.h"
	#include "idmap2/ResourceMapping.h"
	#include "idmap2/ResourceUtils.h"
	#include "idmap2/Result.h"
	#include "idmap2/SysTrace.h"

	namespace android::idmap2 {

	namespace {

	bool WARN_UNUSED Read8(std::istream& stream, uint8_t* out) {
	uint8_t value;
	if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint8_t))) {
	*out = value;
	return true;
	}
	return false;
	}

	bool WARN_UNUSED Read16(std::istream& stream, uint16_t* out) {
	uint16_t value;
	if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint16_t))) {
	*out = dtohs(value);
	return true;
	}
	return false;
	}

	bool WARN_UNUSED Read32(std::istream& stream, uint32_t* out) {
	uint32_t value;
	if (stream.read(reinterpret_cast<char*>(&value), sizeof(uint32_t))) {
	*out = dtohl(value);
	return true;
	}
	return false;
	}

	bool WARN_UNUSED ReadString(std::istream& stream, std::string* out) {
	uint32_t size;
	if (!Read32(stream, &size)) {
	return false;
	}
	if (size == 0) {
	*out = "";
	return true;
	}
	std::string buf(size, '\0');
	if (!stream.read(buf.data(), size)) {
	return false;
	}
	uint32_t padding_size = CalculatePadding(size);
	if (padding_size != 0 && !stream.seekg(padding_size, std::ios_base::cur)) {
	return false;
	}
	*out = buf;
	return true;
	}

	} // namespace

	std::unique_ptr<const IdmapHeader> IdmapHeader::FromBinaryStream(std::istream& stream) {
	std::unique_ptr<IdmapHeader> idmap_header(new IdmapHeader());
	if (!Read32(stream, &idmap_header->magic_) \|\| !Read32(stream, &idmap_header->version_)) {
	return nullptr;
	}

	if (idmap_header->magic_ != kIdmapMagic \|\| idmap_header->version_ != kIdmapCurrentVersion) {
	// Do not continue parsing if the file is not a current version idmap.
	return nullptr;
	}

	uint32_t enforce_overlayable;
	if (!Read32(stream, &idmap_header->target_crc_) \|\| !Read32(stream, &idmap_header->overlay_crc_) \|\|
	!Read32(stream, &idmap_header->fulfilled_policies_) \|\|
	!Read32(stream, &enforce_overlayable) \|\| !ReadString(stream, &idmap_header->target_path_) \|\|
	!ReadString(stream, &idmap_header->overlay_path_) \|\|
	!ReadString(stream, &idmap_header->overlay_name_) \|\|
	!ReadString(stream, &idmap_header->debug_info_)) {
	return nullptr;
	}

	idmap_header->enforce_overlayable_ = enforce_overlayable != 0U;
	return std::move(idmap_header);
	}

	Result<Unit> IdmapHeader::IsUpToDate(const TargetResourceContainer& target,
	const OverlayResourceContainer& overlay,
	const std::string& overlay_name,
	PolicyBitmask fulfilled_policies,
	bool enforce_overlayable) const {
	const Result<uint32_t> target_crc = target.GetCrc();
	if (!target_crc) {
	return Error("failed to get target crc");
	}

	const Result<uint32_t> overlay_crc = overlay.GetCrc();
	if (!overlay_crc) {
	return Error("failed to get overlay crc");
	}

	return IsUpToDate(target.GetPath(), overlay.GetPath(), overlay_name, target_crc, overlay_crc,
	fulfilled_policies, enforce_overlayable);
	}

	Result<Unit> IdmapHeader::IsUpToDate(const std::string& target_path,
	const std::string& overlay_path,
	const std::string& overlay_name, uint32_t target_crc,
	uint32_t overlay_crc, PolicyBitmask fulfilled_policies,
	bool enforce_overlayable) const {
	if (magic_ != kIdmapMagic) {
	return Error("bad magic: actual 0x%08x, expected 0x%08x", magic_, kIdmapMagic);
	}

	if (version_ != kIdmapCurrentVersion) {
	return Error("bad version: actual 0x%08x, expected 0x%08x", version_, kIdmapCurrentVersion);
	}

	if (target_crc_ != target_crc) {
	return Error("bad target crc: idmap version 0x%08x, file system version 0x%08x", target_crc_,
	target_crc);
	}

	if (overlay_crc_ != overlay_crc) {
	return Error("bad overlay crc: idmap version 0x%08x, file system version 0x%08x", overlay_crc_,
	overlay_crc);
	}

	if (fulfilled_policies_ != fulfilled_policies) {
	return Error("bad fulfilled policies: idmap version 0x%08x, file system version 0x%08x",
	fulfilled_policies, fulfilled_policies_);
	}

	if (enforce_overlayable != enforce_overlayable_) {
	return Error("bad enforce overlayable: idmap version %s, file system version %s",
	enforce_overlayable ? "true" : "false", enforce_overlayable_ ? "true" : "false");
	}

	if (target_path != target_path_) {
	return Error("bad target path: idmap version %s, file system version %s", target_path.c_str(),
	target_path_.c_str());
	}

	if (overlay_path != overlay_path_) {
	return Error("bad overlay path: idmap version %s, file system version %s", overlay_path.c_str(),
	overlay_path_.c_str());
	}

	if (overlay_name != overlay_name_) {
	return Error("bad overlay name: idmap version %s, file system version %s", overlay_name.c_str(),
	overlay_name_.c_str());
	}

	return Unit{};
	}

	std::unique_ptr<const IdmapData::Header> IdmapData::Header::FromBinaryStream(std::istream& stream) {
	std::unique_ptr<IdmapData::Header> idmap_data_header(new IdmapData::Header());
	if (!Read32(stream, &idmap_data_header->target_entry_count) \|\|
	!Read32(stream, &idmap_data_header->target_entry_inline_count) \|\|
	!Read32(stream, &idmap_data_header->target_entry_inline_value_count) \|\|
	!Read32(stream, &idmap_data_header->config_count) \|\|
	!Read32(stream, &idmap_data_header->overlay_entry_count) \|\|
	!Read32(stream, &idmap_data_header->string_pool_index_offset)) {
	return nullptr;
	}

	return std::move(idmap_data_header);
	}

	std::unique_ptr<const IdmapData> IdmapData::FromBinaryStream(std::istream& stream) {
	std::unique_ptr<IdmapData> data(new IdmapData());
	data->header_ = IdmapData::Header::FromBinaryStream(stream);
	if (!data->header_) {
	return nullptr;
	}

	// Read the mapping of target resource id to overlay resource value.
	for (size_t i = 0; i < data->header_->GetTargetEntryCount(); i++) {
	TargetEntry target_entry{};
	if (!Read32(stream, &target_entry.target_id) \|\| !Read32(stream, &target_entry.overlay_id)) {
	return nullptr;
	}
	data->target_entries_.emplace_back(target_entry);
	}

	// Read the mapping of target resource id to inline overlay values.
	std::vector<std::tuple<TargetInlineEntry, uint32_t, uint32_t>> target_inline_entries;
	for (size_t i = 0; i < data->header_->GetTargetInlineEntryCount(); i++) {
	TargetInlineEntry target_entry{};
	uint32_t entry_offset;
	uint32_t entry_count;
	if (!Read32(stream, &target_entry.target_id) \|\| !Read32(stream, &entry_offset)
	\|\| !Read32(stream, &entry_count)) {
	return nullptr;
	}
	target_inline_entries.emplace_back(target_entry, entry_offset, entry_count);
	}

	// Read the inline overlay resource values
	std::vector<std::pair<uint32_t, TargetValue>> target_values;
	uint8_t unused1;
	uint16_t unused2;
	for (size_t i = 0; i < data->header_->GetTargetInlineEntryValueCount(); i++) {
	uint32_t config_index;
	if (!Read32(stream, &config_index)) {
	return nullptr;
	}
	TargetValue value;
	if (!Read16(stream, &unused2)
	\|\| !Read8(stream, &unused1)
	\|\| !Read8(stream, &value.data_type)
	\|\| !Read32(stream, &value.data_value)) {
	return nullptr;
	}
	target_values.emplace_back(config_index, value);
	}

	// Read the configurations
	std::vector<ConfigDescription> configurations;
	for (size_t i = 0; i < data->header_->GetConfigCount(); i++) {
	ConfigDescription cd;
	if (!stream.read(reinterpret_cast<char*>(&cd), sizeof(ConfigDescription))) {
	return nullptr;
	}
	configurations.emplace_back(cd);
	}

	// Construct complete target inline entries
	for (auto [target_entry, entry_offset, entry_count] : target_inline_entries) {
	for(size_t i = 0; i < entry_count; i++) {
	const auto& target_value = target_values[entry_offset + i];
	const auto& config = configurations[target_value.first];
	target_entry.values[config] = target_value.second;
	}
	data->target_inline_entries_.emplace_back(target_entry);
	}

	// Read the mapping of overlay resource id to target resource id.
	for (size_t i = 0; i < data->header_->GetOverlayEntryCount(); i++) {
	OverlayEntry overlay_entry{};
	if (!Read32(stream, &overlay_entry.overlay_id) \|\| !Read32(stream, &overlay_entry.target_id)) {
	return nullptr;
	}
	data->overlay_entries_.emplace_back(overlay_entry);
	}

	// Read raw string pool bytes.
	if (!ReadString(stream, &data->string_pool_data_)) {
	return nullptr;
	}
	return std::move(data);
	}

	std::string Idmap::CanonicalIdmapPathFor(const std::string& absolute_dir,
	const std::string& absolute_apk_path) {
	assert(absolute_dir.size() > 0 && absolute_dir[0] == "/");
	assert(absolute_apk_path.size() > 0 && absolute_apk_path[0] == "/");
	std::string copy(++absolute_apk_path.cbegin(), absolute_apk_path.cend());
	replace(copy.begin(), copy.end(), '/', '@');
	return absolute_dir + "/" + copy + "@idmap";
	}

	Result<std::unique_ptr<const Idmap>> Idmap::FromBinaryStream(std::istream& stream) {
	SYSTRACE << "Idmap::FromBinaryStream";
	std::unique_ptr<Idmap> idmap(new Idmap());

	idmap->header_ = IdmapHeader::FromBinaryStream(stream);
	if (!idmap->header_) {
	return Error("failed to parse idmap header");
	}

	// idmap version 0x01 does not specify the number of data blocks that follow
	// the idmap header; assume exactly one data block
	for (int i = 0; i < 1; i++) {
	std::unique_ptr<const IdmapData> data = IdmapData::FromBinaryStream(stream);
	if (!data) {
	return Error("failed to parse data block %d", i);
	}
	idmap->data_.push_back(std::move(data));
	}

	return {std::move(idmap)};
	}

	Result<std::unique_ptr<const IdmapData>> IdmapData::FromResourceMapping(
	const ResourceMapping& resource_mapping) {
	if (resource_mapping.GetTargetToOverlayMap().empty()) {
	return Error("no resources were overlaid");
	}

	std::unique_ptr<IdmapData> data(new IdmapData());
	data->string_pool_data_ = std::string(resource_mapping.GetStringPoolData());
	uint32_t inline_value_count = 0;
	std::set<std::string> config_set;
	for (const auto& mapping : resource_mapping.GetTargetToOverlayMap()) {
	if (auto overlay_resource = std::get_if<ResourceId>(&mapping.second)) {
	data->target_entries_.push_back({mapping.first, *overlay_resource});
	} else {
	std::map<ConfigDescription, TargetValue> values;
	for (const auto& [config, value] : std::get<ConfigMap>(mapping.second)) {
	config_set.insert(config);
	ConfigDescription cd;
	ConfigDescription::Parse(config, &cd);
	values[cd] = value;
	inline_value_count++;
	}
	data->target_inline_entries_.push_back({mapping.first, values});
	}
	}

	for (const auto& mapping : resource_mapping.GetOverlayToTargetMap()) {
	data->overlay_entries_.emplace_back(IdmapData::OverlayEntry{mapping.first, mapping.second});
	}

	std::unique_ptr<IdmapData::Header> data_header(new IdmapData::Header());
	data_header->target_entry_count = static_cast<uint32_t>(data->target_entries_.size());
	data_header->target_entry_inline_count =
	static_cast<uint32_t>(data->target_inline_entries_.size());
	data_header->target_entry_inline_value_count = inline_value_count;
	data_header->config_count = config_set.size();
	data_header->overlay_entry_count = static_cast<uint32_t>(data->overlay_entries_.size());
	data_header->string_pool_index_offset = resource_mapping.GetStringPoolOffset();
	data->header_ = std::move(data_header);
	return {std::move(data)};
	}

	Result<std::unique_ptr<const Idmap>> Idmap::FromContainers(const TargetResourceContainer& target,
	const OverlayResourceContainer& overlay,
	const std::string& overlay_name,
	const PolicyBitmask& fulfilled_policies,
	bool enforce_overlayable) {
	SYSTRACE << "Idmap::FromApkAssets";
	std::unique_ptr<IdmapHeader> header(new IdmapHeader());
	header->magic_ = kIdmapMagic;
	header->version_ = kIdmapCurrentVersion;

	const auto target_crc = target.GetCrc();
	if (!target_crc) {
	return Error(target_crc.GetError(), "failed to get zip CRC for '%s'", target.GetPath().data());
	}
	header->target_crc_ = *target_crc;

	const auto overlay_crc = overlay.GetCrc();
	if (!overlay_crc) {
	return Error(overlay_crc.GetError(), "failed to get zip CRC for '%s'",
	overlay.GetPath().data());
	}
	header->overlay_crc_ = *overlay_crc;

	header->fulfilled_policies_ = fulfilled_policies;
	header->enforce_overlayable_ = enforce_overlayable;
	header->target_path_ = target.GetPath();
	header->overlay_path_ = overlay.GetPath();
	header->overlay_name_ = overlay_name;

	auto info = overlay.FindOverlayInfo(overlay_name);
	if (!info) {
	return Error(info.GetError(), "failed to get overlay info for '%s'", overlay.GetPath().data());
	}

	LogInfo log_info;
	auto resource_mapping = ResourceMapping::FromContainers(
	target, overlay, *info, fulfilled_policies, enforce_overlayable, log_info);
	if (!resource_mapping) {
	return Error(resource_mapping.GetError(), "failed to generate resource map for '%s'",
	overlay.GetPath().data());
	}

	auto idmap_data = IdmapData::FromResourceMapping(*resource_mapping);
	if (!idmap_data) {
	return idmap_data.GetError();
	}

	std::unique_ptr<Idmap> idmap(new Idmap());
	header->debug_info_ = log_info.GetString();
	idmap->header_ = std::move(header);
	idmap->data_.push_back(std::move(*idmap_data));

	return {std::move(idmap)};
	}

	void IdmapHeader::accept(Visitor* v) const {
	assert(v != nullptr);
	v->visit(*this);
	}

	void IdmapData::Header::accept(Visitor* v) const {
	assert(v != nullptr);
	v->visit(*this);
	}

	void IdmapData::accept(Visitor* v) const {
	assert(v != nullptr);
	header_->accept(v);
	v->visit(*this);
	}

	void Idmap::accept(Visitor* v) const {
	assert(v != nullptr);
	header_->accept(v);
	v->visit(*this);
	auto end = data_.cend();
	for (auto iter = data_.cbegin(); iter != end; ++iter) {
	(*iter)->accept(v);
	}
	}

	} // namespace android::idmap2