• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "format/binary/TableFlattener.h"
18 
19 #include <algorithm>
20 #include <numeric>
21 #include <sstream>
22 #include <type_traits>
23 
24 #include "android-base/logging.h"
25 #include "android-base/macros.h"
26 #include "android-base/stringprintf.h"
27 
28 #include "ResourceTable.h"
29 #include "ResourceValues.h"
30 #include "SdkConstants.h"
31 #include "ValueVisitor.h"
32 #include "format/binary/ChunkWriter.h"
33 #include "format/binary/ResourceTypeExtensions.h"
34 #include "util/BigBuffer.h"
35 
36 using namespace android;
37 
38 namespace aapt {
39 
40 namespace {
41 
42 template <typename T>
cmp_ids(const T * a,const T * b)43 static bool cmp_ids(const T* a, const T* b) {
44   return a->id.value() < b->id.value();
45 }
46 
strcpy16_htod(uint16_t * dst,size_t len,const StringPiece16 & src)47 static void strcpy16_htod(uint16_t* dst, size_t len, const StringPiece16& src) {
48   if (len == 0) {
49     return;
50   }
51 
52   size_t i;
53   const char16_t* src_data = src.data();
54   for (i = 0; i < len - 1 && i < src.size(); i++) {
55     dst[i] = util::HostToDevice16((uint16_t)src_data[i]);
56   }
57   dst[i] = 0;
58 }
59 
cmp_style_entries(const Style::Entry & a,const Style::Entry & b)60 static bool cmp_style_entries(const Style::Entry& a, const Style::Entry& b) {
61   if (a.key.id) {
62     if (b.key.id) {
63       return a.key.id.value() < b.key.id.value();
64     }
65     return true;
66   } else if (!b.key.id) {
67     return a.key.name.value() < b.key.name.value();
68   }
69   return false;
70 }
71 
72 struct FlatEntry {
73   ResourceEntry* entry;
74   Value* value;
75 
76   // The entry string pool index to the entry's name.
77   uint32_t entry_key;
78 };
79 
80 class MapFlattenVisitor : public ValueVisitor {
81  public:
82   using ValueVisitor::Visit;
83 
MapFlattenVisitor(ResTable_entry_ext * out_entry,BigBuffer * buffer)84   MapFlattenVisitor(ResTable_entry_ext* out_entry, BigBuffer* buffer)
85       : out_entry_(out_entry), buffer_(buffer) {
86   }
87 
Visit(Attribute * attr)88   void Visit(Attribute* attr) override {
89     {
90       Reference key = Reference(ResourceId(ResTable_map::ATTR_TYPE));
91       BinaryPrimitive val(Res_value::TYPE_INT_DEC, attr->type_mask);
92       FlattenEntry(&key, &val);
93     }
94 
95     if (attr->min_int != std::numeric_limits<int32_t>::min()) {
96       Reference key = Reference(ResourceId(ResTable_map::ATTR_MIN));
97       BinaryPrimitive val(Res_value::TYPE_INT_DEC, static_cast<uint32_t>(attr->min_int));
98       FlattenEntry(&key, &val);
99     }
100 
101     if (attr->max_int != std::numeric_limits<int32_t>::max()) {
102       Reference key = Reference(ResourceId(ResTable_map::ATTR_MAX));
103       BinaryPrimitive val(Res_value::TYPE_INT_DEC, static_cast<uint32_t>(attr->max_int));
104       FlattenEntry(&key, &val);
105     }
106 
107     for (Attribute::Symbol& s : attr->symbols) {
108       BinaryPrimitive val(Res_value::TYPE_INT_DEC, s.value);
109       FlattenEntry(&s.symbol, &val);
110     }
111   }
112 
Visit(Style * style)113   void Visit(Style* style) override {
114     if (style->parent) {
115       const Reference& parent_ref = style->parent.value();
116       CHECK(bool(parent_ref.id)) << "parent has no ID";
117       out_entry_->parent.ident = util::HostToDevice32(parent_ref.id.value().id);
118     }
119 
120     // Sort the style.
121     std::sort(style->entries.begin(), style->entries.end(), cmp_style_entries);
122 
123     for (Style::Entry& entry : style->entries) {
124       FlattenEntry(&entry.key, entry.value.get());
125     }
126   }
127 
Visit(Styleable * styleable)128   void Visit(Styleable* styleable) override {
129     for (auto& attr_ref : styleable->entries) {
130       BinaryPrimitive val(Res_value{});
131       FlattenEntry(&attr_ref, &val);
132     }
133   }
134 
Visit(Array * array)135   void Visit(Array* array) override {
136     for (auto& item : array->elements) {
137       ResTable_map* out_entry = buffer_->NextBlock<ResTable_map>();
138       FlattenValue(item.get(), out_entry);
139       out_entry->value.size = util::HostToDevice16(sizeof(out_entry->value));
140       entry_count_++;
141     }
142   }
143 
Visit(Plural * plural)144   void Visit(Plural* plural) override {
145     const size_t count = plural->values.size();
146     for (size_t i = 0; i < count; i++) {
147       if (!plural->values[i]) {
148         continue;
149       }
150 
151       ResourceId q;
152       switch (i) {
153         case Plural::Zero:
154           q.id = android::ResTable_map::ATTR_ZERO;
155           break;
156 
157         case Plural::One:
158           q.id = android::ResTable_map::ATTR_ONE;
159           break;
160 
161         case Plural::Two:
162           q.id = android::ResTable_map::ATTR_TWO;
163           break;
164 
165         case Plural::Few:
166           q.id = android::ResTable_map::ATTR_FEW;
167           break;
168 
169         case Plural::Many:
170           q.id = android::ResTable_map::ATTR_MANY;
171           break;
172 
173         case Plural::Other:
174           q.id = android::ResTable_map::ATTR_OTHER;
175           break;
176 
177         default:
178           LOG(FATAL) << "unhandled plural type";
179           break;
180       }
181 
182       Reference key(q);
183       FlattenEntry(&key, plural->values[i].get());
184     }
185   }
186 
187   /**
188    * Call this after visiting a Value. This will finish any work that
189    * needs to be done to prepare the entry.
190    */
Finish()191   void Finish() {
192     out_entry_->count = util::HostToDevice32(entry_count_);
193   }
194 
195  private:
196   DISALLOW_COPY_AND_ASSIGN(MapFlattenVisitor);
197 
FlattenKey(Reference * key,ResTable_map * out_entry)198   void FlattenKey(Reference* key, ResTable_map* out_entry) {
199     CHECK(bool(key->id)) << "key has no ID";
200     out_entry->name.ident = util::HostToDevice32(key->id.value().id);
201   }
202 
FlattenValue(Item * value,ResTable_map * out_entry)203   void FlattenValue(Item* value, ResTable_map* out_entry) {
204     CHECK(value->Flatten(&out_entry->value)) << "flatten failed";
205   }
206 
FlattenEntry(Reference * key,Item * value)207   void FlattenEntry(Reference* key, Item* value) {
208     ResTable_map* out_entry = buffer_->NextBlock<ResTable_map>();
209     FlattenKey(key, out_entry);
210     FlattenValue(value, out_entry);
211     out_entry->value.size = util::HostToDevice16(sizeof(out_entry->value));
212     entry_count_++;
213   }
214 
215   ResTable_entry_ext* out_entry_;
216   BigBuffer* buffer_;
217   size_t entry_count_ = 0;
218 };
219 
220 class PackageFlattener {
221  public:
PackageFlattener(IAaptContext * context,ResourceTablePackage * package,const std::map<size_t,std::string> * shared_libs,bool use_sparse_entries,bool collapse_key_stringpool,const std::set<std::string> & whitelisted_resources)222   PackageFlattener(IAaptContext* context, ResourceTablePackage* package,
223                    const std::map<size_t, std::string>* shared_libs, bool use_sparse_entries,
224                    bool collapse_key_stringpool, const std::set<std::string>& whitelisted_resources)
225       : context_(context),
226         diag_(context->GetDiagnostics()),
227         package_(package),
228         shared_libs_(shared_libs),
229         use_sparse_entries_(use_sparse_entries),
230         collapse_key_stringpool_(collapse_key_stringpool),
231         whitelisted_resources_(whitelisted_resources) {
232   }
233 
FlattenPackage(BigBuffer * buffer)234   bool FlattenPackage(BigBuffer* buffer) {
235     ChunkWriter pkg_writer(buffer);
236     ResTable_package* pkg_header = pkg_writer.StartChunk<ResTable_package>(RES_TABLE_PACKAGE_TYPE);
237     pkg_header->id = util::HostToDevice32(package_->id.value());
238 
239     // AAPT truncated the package name, so do the same.
240     // Shared libraries require full package names, so don't truncate theirs.
241     if (context_->GetPackageType() != PackageType::kApp &&
242         package_->name.size() >= arraysize(pkg_header->name)) {
243       diag_->Error(DiagMessage() << "package name '" << package_->name
244                                  << "' is too long. "
245                                     "Shared libraries cannot have truncated package names");
246       return false;
247     }
248 
249     // Copy the package name in device endianness.
250     strcpy16_htod(pkg_header->name, arraysize(pkg_header->name), util::Utf8ToUtf16(package_->name));
251 
252     // Serialize the types. We do this now so that our type and key strings
253     // are populated. We write those first.
254     BigBuffer type_buffer(1024);
255     FlattenTypes(&type_buffer);
256 
257     pkg_header->typeStrings = util::HostToDevice32(pkg_writer.size());
258     StringPool::FlattenUtf16(pkg_writer.buffer(), type_pool_, diag_);
259 
260     pkg_header->keyStrings = util::HostToDevice32(pkg_writer.size());
261     StringPool::FlattenUtf8(pkg_writer.buffer(), key_pool_, diag_);
262 
263     // Append the types.
264     buffer->AppendBuffer(std::move(type_buffer));
265 
266     // If there are libraries (or if the package ID is 0x00), encode a library chunk.
267     if (package_->id.value() == 0x00 || !shared_libs_->empty()) {
268       FlattenLibrarySpec(buffer);
269     }
270 
271     pkg_writer.Finish();
272     return true;
273   }
274 
275  private:
276   DISALLOW_COPY_AND_ASSIGN(PackageFlattener);
277 
278   template <typename T, bool IsItem>
WriteEntry(FlatEntry * entry,BigBuffer * buffer)279   T* WriteEntry(FlatEntry* entry, BigBuffer* buffer) {
280     static_assert(
281         std::is_same<ResTable_entry, T>::value || std::is_same<ResTable_entry_ext, T>::value,
282         "T must be ResTable_entry or ResTable_entry_ext");
283 
284     T* result = buffer->NextBlock<T>();
285     ResTable_entry* out_entry = (ResTable_entry*)result;
286     if (entry->entry->visibility.level == Visibility::Level::kPublic) {
287       out_entry->flags |= ResTable_entry::FLAG_PUBLIC;
288     }
289 
290     if (entry->value->IsWeak()) {
291       out_entry->flags |= ResTable_entry::FLAG_WEAK;
292     }
293 
294     if (!IsItem) {
295       out_entry->flags |= ResTable_entry::FLAG_COMPLEX;
296     }
297 
298     out_entry->flags = util::HostToDevice16(out_entry->flags);
299     out_entry->key.index = util::HostToDevice32(entry->entry_key);
300     out_entry->size = util::HostToDevice16(sizeof(T));
301     return result;
302   }
303 
FlattenValue(FlatEntry * entry,BigBuffer * buffer)304   bool FlattenValue(FlatEntry* entry, BigBuffer* buffer) {
305     if (Item* item = ValueCast<Item>(entry->value)) {
306       WriteEntry<ResTable_entry, true>(entry, buffer);
307       Res_value* outValue = buffer->NextBlock<Res_value>();
308       CHECK(item->Flatten(outValue)) << "flatten failed";
309       outValue->size = util::HostToDevice16(sizeof(*outValue));
310     } else {
311       ResTable_entry_ext* out_entry = WriteEntry<ResTable_entry_ext, false>(entry, buffer);
312       MapFlattenVisitor visitor(out_entry, buffer);
313       entry->value->Accept(&visitor);
314       visitor.Finish();
315     }
316     return true;
317   }
318 
FlattenConfig(const ResourceTableType * type,const ConfigDescription & config,const size_t num_total_entries,std::vector<FlatEntry> * entries,BigBuffer * buffer)319   bool FlattenConfig(const ResourceTableType* type, const ConfigDescription& config,
320                      const size_t num_total_entries, std::vector<FlatEntry>* entries,
321                      BigBuffer* buffer) {
322     CHECK(num_total_entries != 0);
323     CHECK(num_total_entries <= std::numeric_limits<uint16_t>::max());
324 
325     ChunkWriter type_writer(buffer);
326     ResTable_type* type_header = type_writer.StartChunk<ResTable_type>(RES_TABLE_TYPE_TYPE);
327     type_header->id = type->id.value();
328     type_header->config = config;
329     type_header->config.swapHtoD();
330 
331     std::vector<uint32_t> offsets;
332     offsets.resize(num_total_entries, 0xffffffffu);
333 
334     BigBuffer values_buffer(512);
335     for (FlatEntry& flat_entry : *entries) {
336       CHECK(static_cast<size_t>(flat_entry.entry->id.value()) < num_total_entries);
337       offsets[flat_entry.entry->id.value()] = values_buffer.size();
338       if (!FlattenValue(&flat_entry, &values_buffer)) {
339         diag_->Error(DiagMessage()
340                      << "failed to flatten resource '"
341                      << ResourceNameRef(package_->name, type->type, flat_entry.entry->name)
342                      << "' for configuration '" << config << "'");
343         return false;
344       }
345     }
346 
347     bool sparse_encode = use_sparse_entries_;
348 
349     // Only sparse encode if the entries will be read on platforms O+.
350     sparse_encode =
351         sparse_encode && (context_->GetMinSdkVersion() >= SDK_O || config.sdkVersion >= SDK_O);
352 
353     // Only sparse encode if the offsets are representable in 2 bytes.
354     sparse_encode =
355         sparse_encode && (values_buffer.size() / 4u) <= std::numeric_limits<uint16_t>::max();
356 
357     // Only sparse encode if the ratio of populated entries to total entries is below some
358     // threshold.
359     sparse_encode =
360         sparse_encode && ((100 * entries->size()) / num_total_entries) < kSparseEncodingThreshold;
361 
362     if (sparse_encode) {
363       type_header->entryCount = util::HostToDevice32(entries->size());
364       type_header->flags |= ResTable_type::FLAG_SPARSE;
365       ResTable_sparseTypeEntry* indices =
366           type_writer.NextBlock<ResTable_sparseTypeEntry>(entries->size());
367       for (size_t i = 0; i < num_total_entries; i++) {
368         if (offsets[i] != ResTable_type::NO_ENTRY) {
369           CHECK((offsets[i] & 0x03) == 0);
370           indices->idx = util::HostToDevice16(i);
371           indices->offset = util::HostToDevice16(offsets[i] / 4u);
372           indices++;
373         }
374       }
375     } else {
376       type_header->entryCount = util::HostToDevice32(num_total_entries);
377       uint32_t* indices = type_writer.NextBlock<uint32_t>(num_total_entries);
378       for (size_t i = 0; i < num_total_entries; i++) {
379         indices[i] = util::HostToDevice32(offsets[i]);
380       }
381     }
382 
383     type_header->entriesStart = util::HostToDevice32(type_writer.size());
384     type_writer.buffer()->AppendBuffer(std::move(values_buffer));
385     type_writer.Finish();
386     return true;
387   }
388 
CollectAndSortTypes()389   std::vector<ResourceTableType*> CollectAndSortTypes() {
390     std::vector<ResourceTableType*> sorted_types;
391     for (auto& type : package_->types) {
392       if (type->type == ResourceType::kStyleable) {
393         // Styleables aren't real Resource Types, they are represented in the
394         // R.java file.
395         continue;
396       }
397 
398       CHECK(bool(type->id)) << "type must have an ID set";
399 
400       sorted_types.push_back(type.get());
401     }
402     std::sort(sorted_types.begin(), sorted_types.end(), cmp_ids<ResourceTableType>);
403     return sorted_types;
404   }
405 
CollectAndSortEntries(ResourceTableType * type)406   std::vector<ResourceEntry*> CollectAndSortEntries(ResourceTableType* type) {
407     // Sort the entries by entry ID.
408     std::vector<ResourceEntry*> sorted_entries;
409     for (auto& entry : type->entries) {
410       CHECK(bool(entry->id)) << "entry must have an ID set";
411       sorted_entries.push_back(entry.get());
412     }
413     std::sort(sorted_entries.begin(), sorted_entries.end(), cmp_ids<ResourceEntry>);
414     return sorted_entries;
415   }
416 
FlattenTypeSpec(ResourceTableType * type,std::vector<ResourceEntry * > * sorted_entries,BigBuffer * buffer)417   bool FlattenTypeSpec(ResourceTableType* type, std::vector<ResourceEntry*>* sorted_entries,
418                        BigBuffer* buffer) {
419     ChunkWriter type_spec_writer(buffer);
420     ResTable_typeSpec* spec_header =
421         type_spec_writer.StartChunk<ResTable_typeSpec>(RES_TABLE_TYPE_SPEC_TYPE);
422     spec_header->id = type->id.value();
423 
424     if (sorted_entries->empty()) {
425       type_spec_writer.Finish();
426       return true;
427     }
428 
429     // We can't just take the size of the vector. There may be holes in the
430     // entry ID space.
431     // Since the entries are sorted by ID, the last one will be the biggest.
432     const size_t num_entries = sorted_entries->back()->id.value() + 1;
433 
434     spec_header->entryCount = util::HostToDevice32(num_entries);
435 
436     // Reserve space for the masks of each resource in this type. These
437     // show for which configuration axis the resource changes.
438     uint32_t* config_masks = type_spec_writer.NextBlock<uint32_t>(num_entries);
439 
440     const size_t actual_num_entries = sorted_entries->size();
441     for (size_t entryIndex = 0; entryIndex < actual_num_entries; entryIndex++) {
442       ResourceEntry* entry = sorted_entries->at(entryIndex);
443 
444       // Populate the config masks for this entry.
445 
446       if (entry->visibility.level == Visibility::Level::kPublic) {
447         config_masks[entry->id.value()] |= util::HostToDevice32(ResTable_typeSpec::SPEC_PUBLIC);
448       }
449 
450       if (entry->overlayable) {
451         config_masks[entry->id.value()] |=
452             util::HostToDevice32(ResTable_typeSpec::SPEC_OVERLAYABLE);
453       }
454 
455       const size_t config_count = entry->values.size();
456       for (size_t i = 0; i < config_count; i++) {
457         const ConfigDescription& config = entry->values[i]->config;
458         for (size_t j = i + 1; j < config_count; j++) {
459           config_masks[entry->id.value()] |=
460               util::HostToDevice32(config.diff(entry->values[j]->config));
461         }
462       }
463     }
464     type_spec_writer.Finish();
465     return true;
466   }
467 
FlattenTypes(BigBuffer * buffer)468   bool FlattenTypes(BigBuffer* buffer) {
469     // Sort the types by their IDs. They will be inserted into the StringPool in
470     // this order.
471     std::vector<ResourceTableType*> sorted_types = CollectAndSortTypes();
472 
473     size_t expected_type_id = 1;
474     for (ResourceTableType* type : sorted_types) {
475       // If there is a gap in the type IDs, fill in the StringPool
476       // with empty values until we reach the ID we expect.
477       while (type->id.value() > expected_type_id) {
478         std::stringstream type_name;
479         type_name << "?" << expected_type_id;
480         type_pool_.MakeRef(type_name.str());
481         expected_type_id++;
482       }
483       expected_type_id++;
484       type_pool_.MakeRef(to_string(type->type));
485 
486       std::vector<ResourceEntry*> sorted_entries = CollectAndSortEntries(type);
487       if (sorted_entries.empty()) {
488         continue;
489       }
490 
491       if (!FlattenTypeSpec(type, &sorted_entries, buffer)) {
492         return false;
493       }
494 
495       // Since the entries are sorted by ID, the last ID will be the largest.
496       const size_t num_entries = sorted_entries.back()->id.value() + 1;
497 
498       // The binary resource table lists resource entries for each
499       // configuration.
500       // We store them inverted, where a resource entry lists the values for
501       // each
502       // configuration available. Here we reverse this to match the binary
503       // table.
504       std::map<ConfigDescription, std::vector<FlatEntry>> config_to_entry_list_map;
505 
506       // hardcoded string uses characters which make it an invalid resource name
507       const std::string obfuscated_resource_name = "0_resource_name_obfuscated";
508 
509       for (ResourceEntry* entry : sorted_entries) {
510         uint32_t local_key_index;
511         if (!collapse_key_stringpool_ ||
512             whitelisted_resources_.find(entry->name) != whitelisted_resources_.end()) {
513           local_key_index = (uint32_t)key_pool_.MakeRef(entry->name).index();
514         } else {
515           // resource isn't whitelisted, add it as obfuscated value
516           local_key_index = (uint32_t)key_pool_.MakeRef(obfuscated_resource_name).index();
517         }
518         // Group values by configuration.
519         for (auto& config_value : entry->values) {
520           config_to_entry_list_map[config_value->config].push_back(
521               FlatEntry{entry, config_value->value.get(), local_key_index});
522         }
523       }
524 
525       // Flatten a configuration value.
526       for (auto& entry : config_to_entry_list_map) {
527         if (!FlattenConfig(type, entry.first, num_entries, &entry.second, buffer)) {
528           return false;
529         }
530       }
531     }
532     return true;
533   }
534 
FlattenLibrarySpec(BigBuffer * buffer)535   void FlattenLibrarySpec(BigBuffer* buffer) {
536     ChunkWriter lib_writer(buffer);
537     ResTable_lib_header* lib_header =
538         lib_writer.StartChunk<ResTable_lib_header>(RES_TABLE_LIBRARY_TYPE);
539 
540     const size_t num_entries = (package_->id.value() == 0x00 ? 1 : 0) + shared_libs_->size();
541     CHECK(num_entries > 0);
542 
543     lib_header->count = util::HostToDevice32(num_entries);
544 
545     ResTable_lib_entry* lib_entry = buffer->NextBlock<ResTable_lib_entry>(num_entries);
546     if (package_->id.value() == 0x00) {
547       // Add this package
548       lib_entry->packageId = util::HostToDevice32(0x00);
549       strcpy16_htod(lib_entry->packageName, arraysize(lib_entry->packageName),
550                     util::Utf8ToUtf16(package_->name));
551       ++lib_entry;
552     }
553 
554     for (auto& map_entry : *shared_libs_) {
555       lib_entry->packageId = util::HostToDevice32(map_entry.first);
556       strcpy16_htod(lib_entry->packageName, arraysize(lib_entry->packageName),
557                     util::Utf8ToUtf16(map_entry.second));
558       ++lib_entry;
559     }
560     lib_writer.Finish();
561   }
562 
563   IAaptContext* context_;
564   IDiagnostics* diag_;
565   ResourceTablePackage* package_;
566   const std::map<size_t, std::string>* shared_libs_;
567   bool use_sparse_entries_;
568   StringPool type_pool_;
569   StringPool key_pool_;
570   bool collapse_key_stringpool_;
571   const std::set<std::string>& whitelisted_resources_;
572 };
573 
574 }  // namespace
575 
Consume(IAaptContext * context,ResourceTable * table)576 bool TableFlattener::Consume(IAaptContext* context, ResourceTable* table) {
577   // We must do this before writing the resources, since the string pool IDs may change.
578   table->string_pool.Prune();
579   table->string_pool.Sort([](const StringPool::Context& a, const StringPool::Context& b) -> int {
580     int diff = util::compare(a.priority, b.priority);
581     if (diff == 0) {
582       diff = a.config.compare(b.config);
583     }
584     return diff;
585   });
586 
587   // Write the ResTable header.
588   ChunkWriter table_writer(buffer_);
589   ResTable_header* table_header = table_writer.StartChunk<ResTable_header>(RES_TABLE_TYPE);
590   table_header->packageCount = util::HostToDevice32(table->packages.size());
591 
592   // Flatten the values string pool.
593   StringPool::FlattenUtf8(table_writer.buffer(), table->string_pool,
594       context->GetDiagnostics());
595 
596   BigBuffer package_buffer(1024);
597 
598   // Flatten each package.
599   for (auto& package : table->packages) {
600     if (context->GetPackageType() == PackageType::kApp) {
601       // Write a self mapping entry for this package if the ID is non-standard (0x7f).
602       const uint8_t package_id = package->id.value();
603       if (package_id != kFrameworkPackageId && package_id != kAppPackageId) {
604         auto result = table->included_packages_.insert({package_id, package->name});
605         if (!result.second && result.first->second != package->name) {
606           // A mapping for this package ID already exists, and is a different package. Error!
607           context->GetDiagnostics()->Error(
608               DiagMessage() << android::base::StringPrintf(
609                   "can't map package ID %02x to '%s'. Already mapped to '%s'", package_id,
610                   package->name.c_str(), result.first->second.c_str()));
611           return false;
612         }
613       }
614     }
615 
616     PackageFlattener flattener(context, package.get(), &table->included_packages_,
617                                options_.use_sparse_entries, options_.collapse_key_stringpool,
618                                options_.whitelisted_resources);
619     if (!flattener.FlattenPackage(&package_buffer)) {
620       return false;
621     }
622   }
623 
624   // Finally merge all the packages into the main buffer.
625   table_writer.buffer()->AppendBuffer(std::move(package_buffer));
626   table_writer.Finish();
627   return true;
628 }
629 
630 }  // namespace aapt
631