Home | History | Annotate | Download | only in java
      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 "java/JavaClassGenerator.h"
     18 
     19 #include <algorithm>
     20 #include <ostream>
     21 #include <set>
     22 #include <sstream>
     23 #include <tuple>
     24 
     25 #include "android-base/errors.h"
     26 #include "android-base/logging.h"
     27 #include "android-base/stringprintf.h"
     28 #include "androidfw/StringPiece.h"
     29 
     30 #include "NameMangler.h"
     31 #include "Resource.h"
     32 #include "ResourceTable.h"
     33 #include "ResourceValues.h"
     34 #include "SdkConstants.h"
     35 #include "ValueVisitor.h"
     36 #include "java/AnnotationProcessor.h"
     37 #include "java/ClassDefinition.h"
     38 #include "process/SymbolTable.h"
     39 
     40 using ::aapt::io::OutputStream;
     41 using ::aapt::text::Printer;
     42 using ::android::StringPiece;
     43 using ::android::base::StringPrintf;
     44 
     45 namespace aapt {
     46 
     47 static const std::set<StringPiece> sJavaIdentifiers = {
     48     "abstract",   "assert",       "boolean",   "break",      "byte",
     49     "case",       "catch",        "char",      "class",      "const",
     50     "continue",   "default",      "do",        "double",     "else",
     51     "enum",       "extends",      "final",     "finally",    "float",
     52     "for",        "goto",         "if",        "implements", "import",
     53     "instanceof", "int",          "interface", "long",       "native",
     54     "new",        "package",      "private",   "protected",  "public",
     55     "return",     "short",        "static",    "strictfp",   "super",
     56     "switch",     "synchronized", "this",      "throw",      "throws",
     57     "transient",  "try",          "void",      "volatile",   "while",
     58     "true",       "false",        "null"};
     59 
     60 static bool IsValidSymbol(const StringPiece& symbol) {
     61   return sJavaIdentifiers.find(symbol) == sJavaIdentifiers.end();
     62 }
     63 
     64 // Java symbols can not contain . or -, but those are valid in a resource name.
     65 // Replace those with '_'.
     66 std::string JavaClassGenerator::TransformToFieldName(const StringPiece& symbol) {
     67   std::string output = symbol.to_string();
     68   for (char& c : output) {
     69     if (c == '.' || c == '-') {
     70       c = '_';
     71     }
     72   }
     73   return output;
     74 }
     75 
     76 // Transforms an attribute in a styleable to the Java field name:
     77 //
     78 // <declare-styleable name="Foo">
     79 //   <attr name="android:bar" />
     80 //   <attr name="bar" />
     81 // </declare-styleable>
     82 //
     83 // Foo_android_bar
     84 // Foo_bar
     85 static std::string TransformNestedAttr(const ResourceNameRef& attr_name,
     86                                        const std::string& styleable_class_name,
     87                                        const StringPiece& package_name_to_generate) {
     88   std::string output = styleable_class_name;
     89 
     90   // We may reference IDs from other packages, so prefix the entry name with
     91   // the package.
     92   if (!attr_name.package.empty() &&
     93       package_name_to_generate != attr_name.package) {
     94     output += "_" + JavaClassGenerator::TransformToFieldName(attr_name.package);
     95   }
     96   output += "_" + JavaClassGenerator::TransformToFieldName(attr_name.entry);
     97   return output;
     98 }
     99 
    100 static void AddAttributeFormatDoc(AnnotationProcessor* processor, Attribute* attr) {
    101   const uint32_t type_mask = attr->type_mask;
    102   if (type_mask & android::ResTable_map::TYPE_REFERENCE) {
    103     processor->AppendComment(
    104         "<p>May be a reference to another resource, in the form\n"
    105         "\"<code>@[+][<i>package</i>:]<i>type</i>/<i>name</i></code>\" or a "
    106         "theme\n"
    107         "attribute in the form\n"
    108         "\"<code>?[<i>package</i>:]<i>type</i>/<i>name</i></code>\".");
    109   }
    110 
    111   if (type_mask & android::ResTable_map::TYPE_STRING) {
    112     processor->AppendComment(
    113         "<p>May be a string value, using '\\\\;' to escape characters such as\n"
    114         "'\\\\n' or '\\\\uxxxx' for a unicode character;");
    115   }
    116 
    117   if (type_mask & android::ResTable_map::TYPE_INTEGER) {
    118     processor->AppendComment(
    119         "<p>May be an integer value, such as \"<code>100</code>\".");
    120   }
    121 
    122   if (type_mask & android::ResTable_map::TYPE_BOOLEAN) {
    123     processor->AppendComment(
    124         "<p>May be a boolean value, such as \"<code>true</code>\" or\n"
    125         "\"<code>false</code>\".");
    126   }
    127 
    128   if (type_mask & android::ResTable_map::TYPE_COLOR) {
    129     processor->AppendComment(
    130         "<p>May be a color value, in the form of "
    131         "\"<code>#<i>rgb</i></code>\",\n"
    132         "\"<code>#<i>argb</i></code>\", \"<code>#<i>rrggbb</i></code>\", or \n"
    133         "\"<code>#<i>aarrggbb</i></code>\".");
    134   }
    135 
    136   if (type_mask & android::ResTable_map::TYPE_FLOAT) {
    137     processor->AppendComment(
    138         "<p>May be a floating point value, such as \"<code>1.2</code>\".");
    139   }
    140 
    141   if (type_mask & android::ResTable_map::TYPE_DIMENSION) {
    142     processor->AppendComment(
    143         "<p>May be a dimension value, which is a floating point number "
    144         "appended with a\n"
    145         "unit such as \"<code>14.5sp</code>\".\n"
    146         "Available units are: px (pixels), dp (density-independent pixels),\n"
    147         "sp (scaled pixels based on preferred font size), in (inches), and\n"
    148         "mm (millimeters).");
    149   }
    150 
    151   if (type_mask & android::ResTable_map::TYPE_FRACTION) {
    152     processor->AppendComment(
    153         "<p>May be a fractional value, which is a floating point number "
    154         "appended with\n"
    155         "either % or %p, such as \"<code>14.5%</code>\".\n"
    156         "The % suffix always means a percentage of the base size;\n"
    157         "the optional %p suffix provides a size relative to some parent "
    158         "container.");
    159   }
    160 
    161   if (type_mask &
    162       (android::ResTable_map::TYPE_FLAGS | android::ResTable_map::TYPE_ENUM)) {
    163     if (type_mask & android::ResTable_map::TYPE_FLAGS) {
    164       processor->AppendComment(
    165           "<p>Must be one or more (separated by '|') of the following "
    166           "constant values.</p>");
    167     } else {
    168       processor->AppendComment(
    169           "<p>Must be one of the following constant values.</p>");
    170     }
    171 
    172     processor->AppendComment(
    173         "<table>\n<colgroup align=\"left\" />\n"
    174         "<colgroup align=\"left\" />\n"
    175         "<colgroup align=\"left\" />\n"
    176         "<tr><th>Constant</th><th>Value</th><th>Description</th></tr>\n");
    177     for (const Attribute::Symbol& symbol : attr->symbols) {
    178       std::stringstream line;
    179       line << "<tr><td>" << symbol.symbol.name.value().entry << "</td>"
    180            << "<td>" << std::hex << symbol.value << std::dec << "</td>"
    181            << "<td>" << util::TrimWhitespace(symbol.symbol.GetComment())
    182            << "</td></tr>";
    183       processor->AppendComment(line.str());
    184     }
    185     processor->AppendComment("</table>");
    186   }
    187 }
    188 
    189 JavaClassGenerator::JavaClassGenerator(IAaptContext* context,
    190                                        ResourceTable* table,
    191                                        const JavaClassGeneratorOptions& options)
    192     : context_(context), table_(table), options_(options) {}
    193 
    194 bool JavaClassGenerator::SkipSymbol(Visibility::Level level) {
    195   switch (options_.types) {
    196     case JavaClassGeneratorOptions::SymbolTypes::kAll:
    197       return false;
    198     case JavaClassGeneratorOptions::SymbolTypes::kPublicPrivate:
    199       return level == Visibility::Level::kUndefined;
    200     case JavaClassGeneratorOptions::SymbolTypes::kPublic:
    201       return level != Visibility::Level::kPublic;
    202   }
    203   return true;
    204 }
    205 
    206 // Whether or not to skip writing this symbol.
    207 bool JavaClassGenerator::SkipSymbol(const Maybe<SymbolTable::Symbol>& symbol) {
    208   return !symbol || (options_.types == JavaClassGeneratorOptions::SymbolTypes::kPublic &&
    209                      !symbol.value().is_public);
    210 }
    211 
    212 struct StyleableAttr {
    213   const Reference* attr_ref = nullptr;
    214   std::string field_name;
    215   Maybe<SymbolTable::Symbol> symbol;
    216 };
    217 
    218 static bool operator<(const StyleableAttr& lhs, const StyleableAttr& rhs) {
    219   const ResourceId lhs_id = lhs.attr_ref->id.value_or_default(ResourceId(0));
    220   const ResourceId rhs_id = rhs.attr_ref->id.value_or_default(ResourceId(0));
    221   if (lhs_id < rhs_id) {
    222     return true;
    223   } else if (lhs_id > rhs_id) {
    224     return false;
    225   } else {
    226     return lhs.attr_ref->name.value() < rhs.attr_ref->name.value();
    227   }
    228 }
    229 
    230 void JavaClassGenerator::ProcessStyleable(const ResourceNameRef& name, const ResourceId& id,
    231                                           const Styleable& styleable,
    232                                           const StringPiece& package_name_to_generate,
    233                                           ClassDefinition* out_class_def,
    234                                           MethodDefinition* out_rewrite_method,
    235                                           Printer* r_txt_printer) {
    236   const std::string array_field_name = TransformToFieldName(name.entry);
    237   std::unique_ptr<ResourceArrayMember> array_def =
    238       util::make_unique<ResourceArrayMember>(array_field_name);
    239 
    240   // The array must be sorted by resource ID.
    241   std::vector<StyleableAttr> sorted_attributes;
    242   sorted_attributes.reserve(styleable.entries.size());
    243   for (const auto& attr : styleable.entries) {
    244     // If we are not encoding final attributes, the styleable entry may have no
    245     // ID if we are building a static library.
    246     CHECK(!options_.use_final || attr.id) << "no ID set for Styleable entry";
    247     CHECK(bool(attr.name)) << "no name set for Styleable entry";
    248 
    249     // We will need the unmangled, transformed name in the comments and the field,
    250     // so create it once and cache it in this StyleableAttr data structure.
    251     StyleableAttr styleable_attr;
    252     styleable_attr.attr_ref = &attr;
    253 
    254     // The field name for this attribute is prefixed by the name of this styleable and
    255     // the package it comes from.
    256     styleable_attr.field_name =
    257         TransformNestedAttr(attr.name.value(), array_field_name, package_name_to_generate);
    258 
    259     // Look up the symbol so that we can write out in the comments what are possible legal values
    260     // for this attribute.
    261     const SymbolTable::Symbol* symbol = context_->GetExternalSymbols()->FindByReference(attr);
    262     if (symbol && symbol->attribute) {
    263       // Copy the symbol data structure because the returned instance can be destroyed.
    264       styleable_attr.symbol = *symbol;
    265     }
    266     sorted_attributes.push_back(std::move(styleable_attr));
    267   }
    268 
    269   // Sort the attributes by ID.
    270   std::sort(sorted_attributes.begin(), sorted_attributes.end());
    271 
    272   // Build the JavaDoc comment for the Styleable array. This has references to child attributes
    273   // and what possible values can be used for them.
    274   const size_t attr_count = sorted_attributes.size();
    275   if (out_class_def != nullptr && attr_count > 0) {
    276     std::stringstream styleable_comment;
    277     if (!styleable.GetComment().empty()) {
    278       styleable_comment << styleable.GetComment() << "\n";
    279     } else {
    280       // Apply a default intro comment if the styleable has no comments of its own.
    281       styleable_comment << "Attributes that can be used with a " << array_field_name << ".\n";
    282     }
    283 
    284     styleable_comment << "<p>Includes the following attributes:</p>\n"
    285                          "<table>\n"
    286                          "<colgroup align=\"left\" />\n"
    287                          "<colgroup align=\"left\" />\n"
    288                          "<tr><th>Attribute</th><th>Description</th></tr>\n";
    289 
    290     // Build the table of attributes with their links and names.
    291     for (const StyleableAttr& entry : sorted_attributes) {
    292       if (SkipSymbol(entry.symbol)) {
    293         continue;
    294       }
    295 
    296       StringPiece attr_comment_line = entry.symbol.value().attribute->GetComment();
    297       if (attr_comment_line.contains("@removed")) {
    298         // Removed attributes are public but hidden from the documentation, so
    299         // don't emit them as part of the class documentation.
    300         continue;
    301       }
    302 
    303       const ResourceName& attr_name = entry.attr_ref->name.value();
    304       styleable_comment << "<tr><td><code>{@link #" << entry.field_name << " "
    305                         << (!attr_name.package.empty() ? attr_name.package
    306                                                        : context_->GetCompilationPackage())
    307                         << ":" << attr_name.entry << "}</code></td>";
    308 
    309       // Only use the comment up until the first '.'. This is to stay compatible with
    310       // the way old AAPT did it (presumably to keep it short and to avoid including
    311       // annotations like @hide which would affect this Styleable).
    312       styleable_comment << "<td>" << AnnotationProcessor::ExtractFirstSentence(attr_comment_line)
    313                         << "</td></tr>\n";
    314     }
    315     styleable_comment << "</table>\n";
    316 
    317     // Generate the @see lines for each attribute.
    318     for (const StyleableAttr& entry : sorted_attributes) {
    319       if (SkipSymbol(entry.symbol)) {
    320         continue;
    321       }
    322       styleable_comment << "@see #" << entry.field_name << "\n";
    323     }
    324 
    325     array_def->GetCommentBuilder()->AppendComment(styleable_comment.str());
    326   }
    327 
    328   if (r_txt_printer != nullptr) {
    329     r_txt_printer->Print("int[] styleable ").Print(array_field_name).Print(" {");
    330   }
    331 
    332   // Add the ResourceIds to the array member.
    333   for (size_t i = 0; i < attr_count; i++) {
    334     const ResourceId id = sorted_attributes[i].attr_ref->id.value_or_default(ResourceId(0));
    335     array_def->AddElement(id);
    336 
    337     if (r_txt_printer != nullptr) {
    338       if (i != 0) {
    339         r_txt_printer->Print(",");
    340       }
    341       r_txt_printer->Print(" ").Print(id.to_string());
    342     }
    343   }
    344 
    345   if (r_txt_printer != nullptr) {
    346     r_txt_printer->Println(" }");
    347   }
    348 
    349   // Add the Styleable array to the Styleable class.
    350   out_class_def->AddMember(std::move(array_def));
    351 
    352   // Now we emit the indices into the array.
    353   for (size_t i = 0; i < attr_count; i++) {
    354     const StyleableAttr& styleable_attr = sorted_attributes[i];
    355     if (SkipSymbol(styleable_attr.symbol)) {
    356       continue;
    357     }
    358 
    359     if (out_class_def != nullptr) {
    360       StringPiece comment = styleable_attr.attr_ref->GetComment();
    361       if (styleable_attr.symbol.value().attribute && comment.empty()) {
    362         comment = styleable_attr.symbol.value().attribute->GetComment();
    363       }
    364 
    365       if (comment.contains("@removed")) {
    366         // Removed attributes are public but hidden from the documentation, so
    367         // don't emit them as part of the class documentation.
    368         continue;
    369       }
    370 
    371       const ResourceName& attr_name = styleable_attr.attr_ref->name.value();
    372 
    373       StringPiece package_name = attr_name.package;
    374       if (package_name.empty()) {
    375         package_name = context_->GetCompilationPackage();
    376       }
    377 
    378       std::unique_ptr<IntMember> index_member =
    379           util::make_unique<IntMember>(sorted_attributes[i].field_name, static_cast<uint32_t>(i));
    380 
    381       AnnotationProcessor* attr_processor = index_member->GetCommentBuilder();
    382 
    383       if (!comment.empty()) {
    384         attr_processor->AppendComment("<p>\n@attr description");
    385         attr_processor->AppendComment(comment);
    386       } else {
    387         std::stringstream default_comment;
    388         default_comment << "<p>This symbol is the offset where the "
    389                         << "{@link " << package_name << ".R.attr#"
    390                         << TransformToFieldName(attr_name.entry) << "}\n"
    391                         << "attribute's value can be found in the "
    392                         << "{@link #" << array_field_name << "} array.";
    393         attr_processor->AppendComment(default_comment.str());
    394       }
    395 
    396       attr_processor->AppendNewLine();
    397       AddAttributeFormatDoc(attr_processor, styleable_attr.symbol.value().attribute.get());
    398       attr_processor->AppendNewLine();
    399       attr_processor->AppendComment(
    400           StringPrintf("@attr name %s:%s", package_name.data(), attr_name.entry.data()));
    401 
    402       out_class_def->AddMember(std::move(index_member));
    403     }
    404 
    405     if (r_txt_printer != nullptr) {
    406       r_txt_printer->Println(
    407           StringPrintf("int styleable %s %zd", sorted_attributes[i].field_name.c_str(), i));
    408     }
    409   }
    410 
    411   // If there is a rewrite method to generate, add the statements that rewrite package IDs
    412   // for this styleable.
    413   if (out_rewrite_method != nullptr) {
    414     out_rewrite_method->AppendStatement(
    415         StringPrintf("for (int i = 0; i < styleable.%s.length; i++) {", array_field_name.data()));
    416     out_rewrite_method->AppendStatement(
    417         StringPrintf("  if ((styleable.%s[i] & 0xff000000) == 0) {", array_field_name.data()));
    418     out_rewrite_method->AppendStatement(
    419         StringPrintf("    styleable.%s[i] = (styleable.%s[i] & 0x00ffffff) | (p << 24);",
    420                      array_field_name.data(), array_field_name.data()));
    421     out_rewrite_method->AppendStatement("  }");
    422     out_rewrite_method->AppendStatement("}");
    423   }
    424 }
    425 
    426 void JavaClassGenerator::ProcessResource(const ResourceNameRef& name, const ResourceId& id,
    427                                          const ResourceEntry& entry, ClassDefinition* out_class_def,
    428                                          MethodDefinition* out_rewrite_method,
    429                                          text::Printer* r_txt_printer) {
    430   ResourceId real_id = id;
    431   if (context_->GetMinSdkVersion() < SDK_O && name.type == ResourceType::kId &&
    432       id.package_id() > kAppPackageId) {
    433     // Workaround for feature splits using package IDs > 0x7F.
    434     // See b/37498913.
    435     real_id = ResourceId(kAppPackageId, id.package_id(), id.entry_id());
    436   }
    437 
    438   const std::string field_name = TransformToFieldName(name.entry);
    439   if (out_class_def != nullptr) {
    440     std::unique_ptr<ResourceMember> resource_member =
    441         util::make_unique<ResourceMember>(field_name, real_id);
    442 
    443     // Build the comments and annotations for this entry.
    444     AnnotationProcessor* processor = resource_member->GetCommentBuilder();
    445 
    446     // Add the comments from any <public> tags.
    447     if (entry.visibility.level != Visibility::Level::kUndefined) {
    448       processor->AppendComment(entry.visibility.comment);
    449     }
    450 
    451     // Add the comments from all configurations of this entry.
    452     for (const auto& config_value : entry.values) {
    453       processor->AppendComment(config_value->value->GetComment());
    454     }
    455 
    456     // If this is an Attribute, append the format Javadoc.
    457     if (!entry.values.empty()) {
    458       if (Attribute* attr = ValueCast<Attribute>(entry.values.front()->value.get())) {
    459         // We list out the available values for the given attribute.
    460         AddAttributeFormatDoc(processor, attr);
    461       }
    462     }
    463 
    464     out_class_def->AddMember(std::move(resource_member));
    465   }
    466 
    467   if (r_txt_printer != nullptr) {
    468     r_txt_printer->Print("int ")
    469         .Print(to_string(name.type))
    470         .Print(" ")
    471         .Print(field_name)
    472         .Print(" ")
    473         .Println(real_id.to_string());
    474   }
    475 
    476   if (out_rewrite_method != nullptr) {
    477     const StringPiece& type_str = to_string(name.type);
    478     out_rewrite_method->AppendStatement(StringPrintf("%s.%s = (%s.%s & 0x00ffffff) | (p << 24);",
    479                                                      type_str.data(), field_name.data(),
    480                                                      type_str.data(), field_name.data()));
    481   }
    482 }
    483 
    484 Maybe<std::string> JavaClassGenerator::UnmangleResource(const StringPiece& package_name,
    485                                                         const StringPiece& package_name_to_generate,
    486                                                         const ResourceEntry& entry) {
    487   if (SkipSymbol(entry.visibility.level)) {
    488     return {};
    489   }
    490 
    491   std::string unmangled_package;
    492   std::string unmangled_name = entry.name;
    493   if (NameMangler::Unmangle(&unmangled_name, &unmangled_package)) {
    494     // The entry name was mangled, and we successfully unmangled it.
    495     // Check that we want to emit this symbol.
    496     if (package_name_to_generate != unmangled_package) {
    497       // Skip the entry if it doesn't belong to the package we're writing.
    498       return {};
    499     }
    500   } else if (package_name_to_generate != package_name) {
    501     // We are processing a mangled package name,
    502     // but this is a non-mangled resource.
    503     return {};
    504   }
    505   return {std::move(unmangled_name)};
    506 }
    507 
    508 bool JavaClassGenerator::ProcessType(const StringPiece& package_name_to_generate,
    509                                      const ResourceTablePackage& package,
    510                                      const ResourceTableType& type,
    511                                      ClassDefinition* out_type_class_def,
    512                                      MethodDefinition* out_rewrite_method_def,
    513                                      Printer* r_txt_printer) {
    514   for (const auto& entry : type.entries) {
    515     const Maybe<std::string> unmangled_name =
    516         UnmangleResource(package.name, package_name_to_generate, *entry);
    517     if (!unmangled_name) {
    518       continue;
    519     }
    520 
    521     // Create an ID if there is one (static libraries don't need one).
    522     ResourceId id;
    523     if (package.id && type.id && entry->id) {
    524       id = ResourceId(package.id.value(), type.id.value(), entry->id.value());
    525     }
    526 
    527     // We need to make sure we hide the fact that we are generating kAttrPrivate attributes.
    528     const ResourceNameRef resource_name(
    529         package_name_to_generate,
    530         type.type == ResourceType::kAttrPrivate ? ResourceType::kAttr : type.type,
    531         unmangled_name.value());
    532 
    533     // Check to see if the unmangled name is a valid Java name (not a keyword).
    534     if (!IsValidSymbol(unmangled_name.value())) {
    535       std::stringstream err;
    536       err << "invalid symbol name '" << resource_name << "'";
    537       error_ = err.str();
    538       return false;
    539     }
    540 
    541     if (resource_name.type == ResourceType::kStyleable) {
    542       CHECK(!entry->values.empty());
    543 
    544       const Styleable* styleable =
    545           static_cast<const Styleable*>(entry->values.front()->value.get());
    546 
    547       ProcessStyleable(resource_name, id, *styleable, package_name_to_generate, out_type_class_def,
    548                        out_rewrite_method_def, r_txt_printer);
    549     } else {
    550       ProcessResource(resource_name, id, *entry, out_type_class_def, out_rewrite_method_def,
    551                       r_txt_printer);
    552     }
    553   }
    554   return true;
    555 }
    556 
    557 bool JavaClassGenerator::Generate(const StringPiece& package_name_to_generate, OutputStream* out,
    558                                   OutputStream* out_r_txt) {
    559   return Generate(package_name_to_generate, package_name_to_generate, out, out_r_txt);
    560 }
    561 
    562 static void AppendJavaDocAnnotations(const std::vector<std::string>& annotations,
    563                                      AnnotationProcessor* processor) {
    564   for (const std::string& annotation : annotations) {
    565     std::string proper_annotation = "@";
    566     proper_annotation += annotation;
    567     processor->AppendComment(proper_annotation);
    568   }
    569 }
    570 
    571 bool JavaClassGenerator::Generate(const StringPiece& package_name_to_generate,
    572                                   const StringPiece& out_package_name, OutputStream* out,
    573                                   OutputStream* out_r_txt) {
    574   ClassDefinition r_class("R", ClassQualifier::kNone, true);
    575   std::unique_ptr<MethodDefinition> rewrite_method;
    576 
    577   std::unique_ptr<Printer> r_txt_printer;
    578   if (out_r_txt != nullptr) {
    579     r_txt_printer = util::make_unique<Printer>(out_r_txt);
    580   }
    581 
    582   // Generate an onResourcesLoaded() callback if requested.
    583   if (out != nullptr && options_.rewrite_callback_options) {
    584     rewrite_method =
    585         util::make_unique<MethodDefinition>("public static void onResourcesLoaded(int p)");
    586     for (const std::string& package_to_callback :
    587          options_.rewrite_callback_options.value().packages_to_callback) {
    588       rewrite_method->AppendStatement(
    589           StringPrintf("%s.R.onResourcesLoaded(p);", package_to_callback.data()));
    590     }
    591   }
    592 
    593   for (const auto& package : table_->packages) {
    594     for (const auto& type : package->types) {
    595       if (type->type == ResourceType::kAttrPrivate) {
    596         // We generate these as part of the kAttr type, so skip them here.
    597         continue;
    598       }
    599 
    600       // Stay consistent with AAPT and generate an empty type class if the R class is public.
    601       const bool force_creation_if_empty =
    602           (options_.types == JavaClassGeneratorOptions::SymbolTypes::kPublic);
    603 
    604       std::unique_ptr<ClassDefinition> class_def;
    605       if (out != nullptr) {
    606         class_def = util::make_unique<ClassDefinition>(
    607             to_string(type->type), ClassQualifier::kStatic, force_creation_if_empty);
    608       }
    609 
    610       if (!ProcessType(package_name_to_generate, *package, *type, class_def.get(),
    611                        rewrite_method.get(), r_txt_printer.get())) {
    612         return false;
    613       }
    614 
    615       if (type->type == ResourceType::kAttr) {
    616         // Also include private attributes in this same class.
    617         const ResourceTableType* priv_type = package->FindType(ResourceType::kAttrPrivate);
    618         if (priv_type) {
    619           if (!ProcessType(package_name_to_generate, *package, *priv_type, class_def.get(),
    620                            rewrite_method.get(), r_txt_printer.get())) {
    621             return false;
    622           }
    623         }
    624       }
    625 
    626       if (out != nullptr && type->type == ResourceType::kStyleable &&
    627           options_.types == JavaClassGeneratorOptions::SymbolTypes::kPublic) {
    628         // When generating a public R class, we don't want Styleable to be part
    629         // of the API. It is only emitted for documentation purposes.
    630         class_def->GetCommentBuilder()->AppendComment("@doconly");
    631       }
    632 
    633       if (out != nullptr) {
    634         AppendJavaDocAnnotations(options_.javadoc_annotations, class_def->GetCommentBuilder());
    635         r_class.AddMember(std::move(class_def));
    636       }
    637     }
    638   }
    639 
    640   if (rewrite_method != nullptr) {
    641     r_class.AddMember(std::move(rewrite_method));
    642   }
    643 
    644   if (out != nullptr) {
    645     AppendJavaDocAnnotations(options_.javadoc_annotations, r_class.GetCommentBuilder());
    646     ClassDefinition::WriteJavaFile(&r_class, out_package_name, options_.use_final, out);
    647   }
    648   return true;
    649 }
    650 
    651 }  // namespace aapt
    652