tools/aapt2/xml/XmlDom.cpp - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2015 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 "XmlDom.h"

 #include <expat.h>

 #include <memory>
 #include <stack>
 #include <string>
 #include <tuple>

 #include "android-base/logging.h"

 #include "ResourceUtils.h"
 #include "trace/TraceBuffer.h"
 #include "XmlPullParser.h"
 #include "util/Util.h"

 using ::android::InputStream;
 using ::android::StringPiece;
 using ::android::StringPiece16;

 namespace aapt {
 namespace xml {

 constexpr char kXmlNamespaceSep = 1;

 struct Stack {
   std::unique_ptr<xml::Element> root;
   std::stack<xml::Element*> node_stack;
   std::unique_ptr<xml::Element> pending_element;
   std::string pending_comment;
   std::unique_ptr<xml::Text> last_text_node;
 };

 // Extracts the namespace and name of an expanded element or attribute name.
 static void SplitName(const char* name, std::string* out_ns, std::string* out_name) {
   const char* p = name;
   while (*p != 0 && *p != kXmlNamespaceSep) {
     p++;
   }

   if (*p == 0) {
     out_ns->clear();
     out_name->assign(name);
   } else {
     out_ns->assign(name, (p - name));
     out_name->assign(p + 1);
   }
 }

 static void FinishPendingText(Stack* stack) {
   if (stack->last_text_node != nullptr) {
     if (!stack->last_text_node->text.empty()) {
       CHECK(!stack->node_stack.empty());
       stack->node_stack.top()->AppendChild(std::move(stack->last_text_node));
     } else {
       // Drop an empty text node.
     }
     stack->last_text_node = nullptr;
   }
 }

 static void XMLCALL StartNamespaceHandler(void* user_data, const char* prefix, const char* uri) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
   FinishPendingText(stack);

   NamespaceDecl decl;
   decl.line_number = XML_GetCurrentLineNumber(parser);
   decl.column_number = XML_GetCurrentColumnNumber(parser);
   decl.prefix = prefix ? prefix : "";
   decl.uri = uri ? uri : "";

   if (stack->pending_element == nullptr) {
     stack->pending_element = util::make_unique<Element>();
   }
   stack->pending_element->namespace_decls.push_back(std::move(decl));
 }

 static void XMLCALL EndNamespaceHandler(void* user_data, const char* /*prefix*/) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
   FinishPendingText(stack);
 }

 static bool less_attribute(const Attribute& lhs, const Attribute& rhs) {
   return std::tie(lhs.namespace_uri, lhs.name, lhs.value) <
          std::tie(rhs.namespace_uri, rhs.name, rhs.value);
 }

 static void XMLCALL StartElementHandler(void* user_data, const char* name, const char** attrs) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
   FinishPendingText(stack);

   std::unique_ptr<Element> el;
   if (stack->pending_element != nullptr) {
     el = std::move(stack->pending_element);
   } else {
     el = util::make_unique<Element>();
   }

   el->line_number = XML_GetCurrentLineNumber(parser);
   el->column_number = XML_GetCurrentColumnNumber(parser);
   el->comment = std::move(stack->pending_comment);

   SplitName(name, &el->namespace_uri, &el->name);

   while (*attrs) {
     Attribute attribute;
     SplitName(*attrs++, &attribute.namespace_uri, &attribute.name);
     attribute.value = *attrs++;
     el->attributes.push_back(std::move(attribute));
   }

   // Sort the attributes.
   std::sort(el->attributes.begin(), el->attributes.end(), less_attribute);

   // Add to the stack.
   Element* this_el = el.get();
   if (!stack->node_stack.empty()) {
     stack->node_stack.top()->AppendChild(std::move(el));
   } else {
     stack->root = std::move(el);
   }
   stack->node_stack.push(this_el);
 }

 static void XMLCALL EndElementHandler(void* user_data, const char* name) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
   FinishPendingText(stack);

   CHECK(!stack->node_stack.empty());
   // stack->nodeStack.top()->comment = std::move(stack->pendingComment);
   stack->node_stack.pop();
 }

 static void XMLCALL CharacterDataHandler(void* user_data, const char* s, int len) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));

   const StringPiece str(s, len);
   if (str.empty()) {
     return;
   }

   // See if we can just append the text to a previous text node.
   if (stack->last_text_node != nullptr) {
     stack->last_text_node->text.append(str.data(), str.size());
     return;
   }

   stack->last_text_node = util::make_unique<Text>();
   stack->last_text_node->line_number = XML_GetCurrentLineNumber(parser);
   stack->last_text_node->column_number = XML_GetCurrentColumnNumber(parser);
   stack->last_text_node->text.assign(str);
 }

 static void XMLCALL CommentDataHandler(void* user_data, const char* comment) {
   XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
   Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
   FinishPendingText(stack);

   if (!stack->pending_comment.empty()) {
     stack->pending_comment += '\n';
   }
   stack->pending_comment += comment;
 }

 std::unique_ptr<XmlResource> Inflate(InputStream* in, android::IDiagnostics* diag,
                                      const android::Source& source) {
   Stack stack;

   std::unique_ptr<std::remove_pointer<XML_Parser>::type, decltype(XML_ParserFree)*> parser = {
       XML_ParserCreateNS(nullptr, kXmlNamespaceSep), XML_ParserFree};
   XML_SetUserData(parser.get(), &stack);
   XML_UseParserAsHandlerArg(parser.get());
   XML_SetElementHandler(parser.get(), StartElementHandler, EndElementHandler);
   XML_SetNamespaceDeclHandler(parser.get(), StartNamespaceHandler, EndNamespaceHandler);
   XML_SetCharacterDataHandler(parser.get(), CharacterDataHandler);
   XML_SetCommentHandler(parser.get(), CommentDataHandler);

   const char* buffer = nullptr;
   size_t buffer_size = 0;
   while (in->Next(reinterpret_cast<const void**>(&buffer), &buffer_size)) {
     if (XML_Parse(parser.get(), buffer, buffer_size, false) == XML_STATUS_ERROR) {
       diag->Error(android::DiagMessage(source.WithLine(XML_GetCurrentLineNumber(parser.get())))
                   << XML_ErrorString(XML_GetErrorCode(parser.get())));
       return {};
     }
   }

   if (in->HadError()) {
     diag->Error(android::DiagMessage(source) << in->GetError());
     return {};
   } else {
     // Finish off the parsing.
     if (XML_Parse(parser.get(), nullptr, 0u, true) == XML_STATUS_ERROR) {
       diag->Error(android::DiagMessage(source.WithLine(XML_GetCurrentLineNumber(parser.get())))
                   << XML_ErrorString(XML_GetErrorCode(parser.get())));
       return {};
     }
   }
   return util::make_unique<XmlResource>(ResourceFile{{}, {}, ResourceFile::Type::kUnknown, source},
                                         android::StringPool{}, std::move(stack.root));
 }

 static void CopyAttributes(Element* el, android::ResXMLParser* parser,
                            android::StringPool* out_pool) {
   const size_t attr_count = parser->getAttributeCount();
   if (attr_count > 0) {
     el->attributes.reserve(attr_count);
     for (size_t i = 0; i < attr_count; i++) {
       Attribute attr;
       size_t len;
       const char16_t* str16 = parser->getAttributeNamespace(i, &len);
       if (str16) {
         attr.namespace_uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
       }

       str16 = parser->getAttributeName(i, &len);
       if (str16) {
         attr.name = android::util::Utf16ToUtf8(StringPiece16(str16, len));
       }

       uint32_t res_id = parser->getAttributeNameResID(i);
       if (res_id > 0) {
         attr.compiled_attribute = AaptAttribute(::aapt::Attribute(), {res_id});
       }

       str16 = parser->getAttributeStringValue(i, &len);
       if (str16) {
         attr.value = android::util::Utf16ToUtf8(StringPiece16(str16, len));
       }

       android::Res_value res_value;
       if (parser->getAttributeValue(i, &res_value) > 0) {
         // Only compile the value if it is not a string, or it is a string that differs from
         // the raw attribute value.
         int32_t raw_value_idx = parser->getAttributeValueStringID(i);
         if (res_value.dataType != android::Res_value::TYPE_STRING || raw_value_idx < 0 ||
             static_cast<uint32_t>(raw_value_idx) != res_value.data) {
           attr.compiled_value = ResourceUtils::ParseBinaryResValue(
               ResourceType::kAnim, {}, parser->getStrings(), res_value, out_pool);
         }
       }

       el->attributes.push_back(std::move(attr));
     }
   }
 }

 std::unique_ptr<XmlResource> Inflate(const void* data, size_t len, std::string* out_error) {
   TRACE_CALL();
   // We import the android namespace because on Windows NO_ERROR is a macro, not
   // an enum, which causes errors when qualifying it with android::
   using namespace android;

   std::unique_ptr<XmlResource> xml_resource = util::make_unique<XmlResource>();

   std::stack<Element*> node_stack;
   std::unique_ptr<Element> pending_element;

   ResXMLTree tree;
   if (tree.setTo(data, len) != NO_ERROR) {
     if (out_error != nullptr) {
       *out_error = "failed to initialize ResXMLTree";
     }
     return {};
   }

   ResXMLParser::event_code_t code;
   while ((code = tree.next()) != ResXMLParser::BAD_DOCUMENT && code != ResXMLParser::END_DOCUMENT) {
     std::unique_ptr<Node> new_node;
     switch (code) {
       case ResXMLParser::START_NAMESPACE: {
         NamespaceDecl decl;
         decl.line_number = tree.getLineNumber();

         size_t len;
         const char16_t* str16 = tree.getNamespacePrefix(&len);
         if (str16) {
           decl.prefix = android::util::Utf16ToUtf8(StringPiece16(str16, len));
         }

         str16 = tree.getNamespaceUri(&len);
         if (str16) {
           decl.uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
         }

         if (pending_element == nullptr) {
           pending_element = util::make_unique<Element>();
         }
         // pending_element is not nullptr
         // NOLINTNEXTLINE(bugprone-use-after-move)
         pending_element->namespace_decls.push_back(std::move(decl));
         break;
       }

       case ResXMLParser::START_TAG: {
         std::unique_ptr<Element> el;
         if (pending_element != nullptr) {
           el = std::move(pending_element);
         } else {
           el = util::make_unique<Element>();
         }
         el->line_number = tree.getLineNumber();

         size_t len;
         const char16_t* str16 = tree.getElementNamespace(&len);
         if (str16) {
           el->namespace_uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
         }

         str16 = tree.getElementName(&len);
         if (str16) {
           el->name = android::util::Utf16ToUtf8(StringPiece16(str16, len));
         }

         Element* this_el = el.get();
         CopyAttributes(el.get(), &tree, &xml_resource->string_pool);

         if (!node_stack.empty()) {
           node_stack.top()->AppendChild(std::move(el));
         } else {
           xml_resource->root = std::move(el);
         }
         node_stack.push(this_el);
         break;
       }

       case ResXMLParser::TEXT: {
         std::unique_ptr<Text> text = util::make_unique<Text>();
         text->line_number = tree.getLineNumber();
         size_t len;
         const char16_t* str16 = tree.getText(&len);
         if (str16) {
           text->text = android::util::Utf16ToUtf8(StringPiece16(str16, len));
         }
         CHECK(!node_stack.empty());
         node_stack.top()->AppendChild(std::move(text));
         break;
       }

       case ResXMLParser::END_NAMESPACE:
         break;

       case ResXMLParser::END_TAG:
         CHECK(!node_stack.empty());
         node_stack.pop();
         break;

       default:
         LOG(FATAL) << "unhandled XML chunk type";
         break;
     }
   }
   return xml_resource;
 }

 std::unique_ptr<XmlResource> XmlResource::Clone() const {
   std::unique_ptr<XmlResource> cloned = util::make_unique<XmlResource>(file);
   CloningValueTransformer cloner(&cloned->string_pool);
   if (root != nullptr) {
     cloned->root = root->CloneElement([&](const xml::Element& src, xml::Element* dst) {
       dst->attributes.reserve(src.attributes.size());
       for (const xml::Attribute& attr : src.attributes) {
         xml::Attribute cloned_attr;
         cloned_attr.name = attr.name;
         cloned_attr.namespace_uri = attr.namespace_uri;
         cloned_attr.value = attr.value;
         cloned_attr.compiled_attribute = attr.compiled_attribute;
         if (attr.compiled_value != nullptr) {
           cloned_attr.compiled_value = attr.compiled_value->Transform(cloner);
         }
         dst->attributes.push_back(std::move(cloned_attr));
       }
     });
   }
   return cloned;
 }

 Element* FindRootElement(Node* node) {
   if (node == nullptr) {
     return nullptr;
   }

   while (node->parent != nullptr) {
     node = node->parent;
   }
   return NodeCast<Element>(node);
 }

 void Element::AppendChild(std::unique_ptr<Node> child) {
   child->parent = this;
   children.push_back(std::move(child));
 }

 void Element::InsertChild(size_t index, std::unique_ptr<Node> child) {
   child->parent = this;
   children.insert(children.begin() + index, std::move(child));
 }

 Attribute* Element::FindAttribute(StringPiece ns, StringPiece name) {
   return const_cast<Attribute*>(static_cast<const Element*>(this)->FindAttribute(ns, name));
 }

 const Attribute* Element::FindAttribute(StringPiece ns, StringPiece name) const {
   for (const auto& attr : attributes) {
     if (ns == attr.namespace_uri && name == attr.name) {
       return &attr;
     }
   }
   return nullptr;
 }

 void Element::RemoveAttribute(StringPiece ns, StringPiece name) {
   auto new_attr_end = std::remove_if(attributes.begin(), attributes.end(),
     [&](const Attribute& attr) -> bool {
       return ns == attr.namespace_uri && name == attr.name;
     });

   attributes.erase(new_attr_end, attributes.end());
 }

 Attribute* Element::FindOrCreateAttribute(StringPiece ns, StringPiece name) {
   Attribute* attr = FindAttribute(ns, name);
   if (attr == nullptr) {
     attributes.push_back(Attribute{std::string(ns), std::string(name)});
     attr = &attributes.back();
   }
   return attr;
 }

 Element* Element::FindChild(StringPiece ns, StringPiece name) {
   return FindChildWithAttribute(ns, name, {}, {}, {});
 }

 const Element* Element::FindChild(StringPiece ns, StringPiece name) const {
   return FindChildWithAttribute(ns, name, {}, {}, {});
 }

 Element* Element::FindChildWithAttribute(StringPiece ns, StringPiece name, StringPiece attr_ns,
                                          StringPiece attr_name, StringPiece attr_value) {
   return const_cast<Element*>(static_cast<const Element*>(this)->FindChildWithAttribute(
       ns, name, attr_ns, attr_name, attr_value));
 }

 const Element* Element::FindChildWithAttribute(StringPiece ns, StringPiece name,
                                                StringPiece attr_ns, StringPiece attr_name,
                                                StringPiece attr_value) const {
   for (const auto& child : children) {
     if (const Element* el = NodeCast<Element>(child.get())) {
       if (ns == el->namespace_uri && name == el->name) {
         if (attr_ns.empty() && attr_name.empty()) {
           return el;
         }

         const Attribute* attr = el->FindAttribute(attr_ns, attr_name);
         if (attr && attr_value == attr->value) {
           return el;
         }
       }
     }
   }
   return nullptr;
 }

 std::vector<Element*> Element::GetChildElements() {
   std::vector<Element*> elements;
   for (auto& child_node : children) {
     if (Element* child = NodeCast<Element>(child_node.get())) {
       elements.push_back(child);
     }
   }
   return elements;
 }

 std::unique_ptr<Node> Element::Clone(const ElementCloneFunc& el_cloner) const {
   auto el = util::make_unique<Element>();
   el->namespace_decls = namespace_decls;
   el->comment = comment;
   el->line_number = line_number;
   el->column_number = column_number;
   el->name = name;
   el->namespace_uri = namespace_uri;
   el->attributes.reserve(attributes.size());
   el_cloner(*this, el.get());
   el->children.reserve(children.size());
   for (const std::unique_ptr<xml::Node>& child : children) {
     el->AppendChild(child->Clone(el_cloner));
   }
   return std::move(el);
 }

 std::unique_ptr<Element> Element::CloneElement(const ElementCloneFunc& el_cloner) const {
   return std::unique_ptr<Element>(static_cast<Element*>(Clone(el_cloner).release()));
 }

 void Element::Accept(Visitor* visitor) {
   visitor->BeforeVisitElement(this);
   visitor->Visit(this);
   visitor->AfterVisitElement(this);
 }

 void Element::Accept(ConstVisitor* visitor) const {
   visitor->BeforeVisitElement(this);
   visitor->Visit(this);
   visitor->AfterVisitElement(this);
 }

 std::unique_ptr<Node> Text::Clone(const ElementCloneFunc&) const {
   auto t = util::make_unique<Text>();
   t->comment = comment;
   t->line_number = line_number;
   t->column_number = column_number;
   t->text = text;
   return std::move(t);
 }

 void Text::Accept(Visitor* visitor) {
   visitor->Visit(this);
 }

 void Text::Accept(ConstVisitor* visitor) const {
   visitor->Visit(this);
 }

 void PackageAwareVisitor::BeforeVisitElement(Element* el) {
   std::vector<PackageDecl> decls;
   for (const NamespaceDecl& decl : el->namespace_decls) {
     if (std::optional<ExtractedPackage> maybe_package = ExtractPackageFromNamespace(decl.uri)) {
       decls.push_back(PackageDecl{decl.prefix, std::move(maybe_package.value())});
     }
   }
   package_decls_.push_back(std::move(decls));
 }

 void PackageAwareVisitor::AfterVisitElement(Element* el) {
   package_decls_.pop_back();
 }

 std::optional<ExtractedPackage> PackageAwareVisitor::TransformPackageAlias(
     StringPiece alias) const {
   if (alias.empty()) {
     return ExtractedPackage{{}, false /*private*/};
   }

   const auto rend = package_decls_.rend();
   for (auto iter = package_decls_.rbegin(); iter != rend; ++iter) {
     const std::vector<PackageDecl>& decls = *iter;
     const auto rend2 = decls.rend();
     for (auto iter2 = decls.rbegin(); iter2 != rend2; ++iter2) {
       const PackageDecl& decl = *iter2;
       if (alias == decl.prefix) {
         if (decl.package.package.empty()) {
           return ExtractedPackage{{}, decl.package.private_namespace};
         }
         return decl.package;
       }
     }
   }
   return {};
 }

 }  // namespace xml
 }  // namespace aapt
	/*
	* Copyright (C) 2015 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 "XmlDom.h"

	#include <expat.h>

	#include <memory>
	#include <stack>
	#include <string>
	#include <tuple>

	#include "android-base/logging.h"

	#include "ResourceUtils.h"
	#include "trace/TraceBuffer.h"
	#include "XmlPullParser.h"
	#include "util/Util.h"

	using ::android::InputStream;
	using ::android::StringPiece;
	using ::android::StringPiece16;

	namespace aapt {
	namespace xml {

	constexpr char kXmlNamespaceSep = 1;

	struct Stack {
	std::unique_ptr<xml::Element> root;
	std::stack<xml::Element*> node_stack;
	std::unique_ptr<xml::Element> pending_element;
	std::string pending_comment;
	std::unique_ptr<xml::Text> last_text_node;
	};

	// Extracts the namespace and name of an expanded element or attribute name.
	static void SplitName(const char* name, std::string* out_ns, std::string* out_name) {
	const char* p = name;
	while (p != 0 && p != kXmlNamespaceSep) {
	p++;
	}

	if (*p == 0) {
	out_ns->clear();
	out_name->assign(name);
	} else {
	out_ns->assign(name, (p - name));
	out_name->assign(p + 1);
	}
	}

	static void FinishPendingText(Stack* stack) {
	if (stack->last_text_node != nullptr) {
	if (!stack->last_text_node->text.empty()) {
	CHECK(!stack->node_stack.empty());
	stack->node_stack.top()->AppendChild(std::move(stack->last_text_node));
	} else {
	// Drop an empty text node.
	}
	stack->last_text_node = nullptr;
	}
	}

	static void XMLCALL StartNamespaceHandler(void* user_data, const char* prefix, const char* uri) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
	FinishPendingText(stack);

	NamespaceDecl decl;
	decl.line_number = XML_GetCurrentLineNumber(parser);
	decl.column_number = XML_GetCurrentColumnNumber(parser);
	decl.prefix = prefix ? prefix : "";
	decl.uri = uri ? uri : "";

	if (stack->pending_element == nullptr) {
	stack->pending_element = util::make_unique<Element>();
	}
	stack->pending_element->namespace_decls.push_back(std::move(decl));
	}

	static void XMLCALL EndNamespaceHandler(void* user_data, const char* /prefix/) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
	FinishPendingText(stack);
	}

	static bool less_attribute(const Attribute& lhs, const Attribute& rhs) {
	return std::tie(lhs.namespace_uri, lhs.name, lhs.value) <
	std::tie(rhs.namespace_uri, rhs.name, rhs.value);
	}

	static void XMLCALL StartElementHandler(void* user_data, const char* name, const char** attrs) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
	FinishPendingText(stack);

	std::unique_ptr<Element> el;
	if (stack->pending_element != nullptr) {
	el = std::move(stack->pending_element);
	} else {
	el = util::make_unique<Element>();
	}

	el->line_number = XML_GetCurrentLineNumber(parser);
	el->column_number = XML_GetCurrentColumnNumber(parser);
	el->comment = std::move(stack->pending_comment);

	SplitName(name, &el->namespace_uri, &el->name);

	while (*attrs) {
	Attribute attribute;
	SplitName(*attrs++, &attribute.namespace_uri, &attribute.name);
	attribute.value = *attrs++;
	el->attributes.push_back(std::move(attribute));
	}

	// Sort the attributes.
	std::sort(el->attributes.begin(), el->attributes.end(), less_attribute);

	// Add to the stack.
	Element* this_el = el.get();
	if (!stack->node_stack.empty()) {
	stack->node_stack.top()->AppendChild(std::move(el));
	} else {
	stack->root = std::move(el);
	}
	stack->node_stack.push(this_el);
	}

	static void XMLCALL EndElementHandler(void* user_data, const char* name) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
	FinishPendingText(stack);

	CHECK(!stack->node_stack.empty());
	// stack->nodeStack.top()->comment = std::move(stack->pendingComment);
	stack->node_stack.pop();
	}

	static void XMLCALL CharacterDataHandler(void* user_data, const char* s, int len) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));

	const StringPiece str(s, len);
	if (str.empty()) {
	return;
	}

	// See if we can just append the text to a previous text node.
	if (stack->last_text_node != nullptr) {
	stack->last_text_node->text.append(str.data(), str.size());
	return;
	}

	stack->last_text_node = util::make_unique<Text>();
	stack->last_text_node->line_number = XML_GetCurrentLineNumber(parser);
	stack->last_text_node->column_number = XML_GetCurrentColumnNumber(parser);
	stack->last_text_node->text.assign(str);
	}

	static void XMLCALL CommentDataHandler(void* user_data, const char* comment) {
	XML_Parser parser = reinterpret_cast<XML_Parser>(user_data);
	Stack* stack = reinterpret_cast<Stack*>(XML_GetUserData(parser));
	FinishPendingText(stack);

	if (!stack->pending_comment.empty()) {
	stack->pending_comment += '\n';
	}
	stack->pending_comment += comment;
	}

	std::unique_ptr<XmlResource> Inflate(InputStream* in, android::IDiagnostics* diag,
	const android::Source& source) {
	Stack stack;

	std::unique_ptr<std::remove_pointer<XML_Parser>::type, decltype(XML_ParserFree)*> parser = {
	XML_ParserCreateNS(nullptr, kXmlNamespaceSep), XML_ParserFree};
	XML_SetUserData(parser.get(), &stack);
	XML_UseParserAsHandlerArg(parser.get());
	XML_SetElementHandler(parser.get(), StartElementHandler, EndElementHandler);
	XML_SetNamespaceDeclHandler(parser.get(), StartNamespaceHandler, EndNamespaceHandler);
	XML_SetCharacterDataHandler(parser.get(), CharacterDataHandler);
	XML_SetCommentHandler(parser.get(), CommentDataHandler);

	const char* buffer = nullptr;
	size_t buffer_size = 0;
	while (in->Next(reinterpret_cast<const void**>(&buffer), &buffer_size)) {
	if (XML_Parse(parser.get(), buffer, buffer_size, false) == XML_STATUS_ERROR) {
	diag->Error(android::DiagMessage(source.WithLine(XML_GetCurrentLineNumber(parser.get())))
	<< XML_ErrorString(XML_GetErrorCode(parser.get())));
	return {};
	}
	}

	if (in->HadError()) {
	diag->Error(android::DiagMessage(source) << in->GetError());
	return {};
	} else {
	// Finish off the parsing.
	if (XML_Parse(parser.get(), nullptr, 0u, true) == XML_STATUS_ERROR) {
	diag->Error(android::DiagMessage(source.WithLine(XML_GetCurrentLineNumber(parser.get())))
	<< XML_ErrorString(XML_GetErrorCode(parser.get())));
	return {};
	}
	}
	return util::make_unique<XmlResource>(ResourceFile{{}, {}, ResourceFile::Type::kUnknown, source},
	android::StringPool{}, std::move(stack.root));
	}

	static void CopyAttributes(Element* el, android::ResXMLParser* parser,
	android::StringPool* out_pool) {
	const size_t attr_count = parser->getAttributeCount();
	if (attr_count > 0) {
	el->attributes.reserve(attr_count);
	for (size_t i = 0; i < attr_count; i++) {
	Attribute attr;
	size_t len;
	const char16_t* str16 = parser->getAttributeNamespace(i, &len);
	if (str16) {
	attr.namespace_uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	str16 = parser->getAttributeName(i, &len);
	if (str16) {
	attr.name = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	uint32_t res_id = parser->getAttributeNameResID(i);
	if (res_id > 0) {
	attr.compiled_attribute = AaptAttribute(::aapt::Attribute(), {res_id});
	}

	str16 = parser->getAttributeStringValue(i, &len);
	if (str16) {
	attr.value = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	android::Res_value res_value;
	if (parser->getAttributeValue(i, &res_value) > 0) {
	// Only compile the value if it is not a string, or it is a string that differs from
	// the raw attribute value.
	int32_t raw_value_idx = parser->getAttributeValueStringID(i);
	if (res_value.dataType != android::Res_value::TYPE_STRING \|\| raw_value_idx < 0 \|\|
	static_cast<uint32_t>(raw_value_idx) != res_value.data) {
	attr.compiled_value = ResourceUtils::ParseBinaryResValue(
	ResourceType::kAnim, {}, parser->getStrings(), res_value, out_pool);
	}
	}

	el->attributes.push_back(std::move(attr));
	}
	}
	}

	std::unique_ptr<XmlResource> Inflate(const void* data, size_t len, std::string* out_error) {
	TRACE_CALL();
	// We import the android namespace because on Windows NO_ERROR is a macro, not
	// an enum, which causes errors when qualifying it with android::
	using namespace android;

	std::unique_ptr<XmlResource> xml_resource = util::make_unique<XmlResource>();

	std::stack<Element*> node_stack;
	std::unique_ptr<Element> pending_element;

	ResXMLTree tree;
	if (tree.setTo(data, len) != NO_ERROR) {
	if (out_error != nullptr) {
	*out_error = "failed to initialize ResXMLTree";
	}
	return {};
	}

	ResXMLParser::event_code_t code;
	while ((code = tree.next()) != ResXMLParser::BAD_DOCUMENT && code != ResXMLParser::END_DOCUMENT) {
	std::unique_ptr<Node> new_node;
	switch (code) {
	case ResXMLParser::START_NAMESPACE: {
	NamespaceDecl decl;
	decl.line_number = tree.getLineNumber();

	size_t len;
	const char16_t* str16 = tree.getNamespacePrefix(&len);
	if (str16) {
	decl.prefix = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	str16 = tree.getNamespaceUri(&len);
	if (str16) {
	decl.uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	if (pending_element == nullptr) {
	pending_element = util::make_unique<Element>();
	}
	// pending_element is not nullptr
	// NOLINTNEXTLINE(bugprone-use-after-move)
	pending_element->namespace_decls.push_back(std::move(decl));
	break;
	}

	case ResXMLParser::START_TAG: {
	std::unique_ptr<Element> el;
	if (pending_element != nullptr) {
	el = std::move(pending_element);
	} else {
	el = util::make_unique<Element>();
	}
	el->line_number = tree.getLineNumber();

	size_t len;
	const char16_t* str16 = tree.getElementNamespace(&len);
	if (str16) {
	el->namespace_uri = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	str16 = tree.getElementName(&len);
	if (str16) {
	el->name = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}

	Element* this_el = el.get();
	CopyAttributes(el.get(), &tree, &xml_resource->string_pool);

	if (!node_stack.empty()) {
	node_stack.top()->AppendChild(std::move(el));
	} else {
	xml_resource->root = std::move(el);
	}
	node_stack.push(this_el);
	break;
	}

	case ResXMLParser::TEXT: {
	std::unique_ptr<Text> text = util::make_unique<Text>();
	text->line_number = tree.getLineNumber();
	size_t len;
	const char16_t* str16 = tree.getText(&len);
	if (str16) {
	text->text = android::util::Utf16ToUtf8(StringPiece16(str16, len));
	}
	CHECK(!node_stack.empty());
	node_stack.top()->AppendChild(std::move(text));
	break;
	}

	case ResXMLParser::END_NAMESPACE:
	break;

	case ResXMLParser::END_TAG:
	CHECK(!node_stack.empty());
	node_stack.pop();
	break;

	default:
	LOG(FATAL) << "unhandled XML chunk type";
	break;
	}
	}
	return xml_resource;
	}

	std::unique_ptr<XmlResource> XmlResource::Clone() const {
	std::unique_ptr<XmlResource> cloned = util::make_unique<XmlResource>(file);
	CloningValueTransformer cloner(&cloned->string_pool);
	if (root != nullptr) {
	cloned->root = root->CloneElement([&](const xml::Element& src, xml::Element* dst) {
	dst->attributes.reserve(src.attributes.size());
	for (const xml::Attribute& attr : src.attributes) {
	xml::Attribute cloned_attr;
	cloned_attr.name = attr.name;
	cloned_attr.namespace_uri = attr.namespace_uri;
	cloned_attr.value = attr.value;
	cloned_attr.compiled_attribute = attr.compiled_attribute;
	if (attr.compiled_value != nullptr) {
	cloned_attr.compiled_value = attr.compiled_value->Transform(cloner);
	}
	dst->attributes.push_back(std::move(cloned_attr));
	}
	});
	}
	return cloned;
	}

	Element* FindRootElement(Node* node) {
	if (node == nullptr) {
	return nullptr;
	}

	while (node->parent != nullptr) {
	node = node->parent;
	}
	return NodeCast<Element>(node);
	}

	void Element::AppendChild(std::unique_ptr<Node> child) {
	child->parent = this;
	children.push_back(std::move(child));
	}

	void Element::InsertChild(size_t index, std::unique_ptr<Node> child) {
	child->parent = this;
	children.insert(children.begin() + index, std::move(child));
	}

	Attribute* Element::FindAttribute(StringPiece ns, StringPiece name) {
	return const_cast<Attribute>(static_cast<const Element>(this)->FindAttribute(ns, name));
	}

	const Attribute* Element::FindAttribute(StringPiece ns, StringPiece name) const {
	for (const auto& attr : attributes) {
	if (ns == attr.namespace_uri && name == attr.name) {
	return &attr;
	}
	}
	return nullptr;
	}

	void Element::RemoveAttribute(StringPiece ns, StringPiece name) {
	auto new_attr_end = std::remove_if(attributes.begin(), attributes.end(),
	[&](const Attribute& attr) -> bool {
	return ns == attr.namespace_uri && name == attr.name;
	});

	attributes.erase(new_attr_end, attributes.end());
	}

	Attribute* Element::FindOrCreateAttribute(StringPiece ns, StringPiece name) {
	Attribute* attr = FindAttribute(ns, name);
	if (attr == nullptr) {
	attributes.push_back(Attribute{std::string(ns), std::string(name)});
	attr = &attributes.back();
	}
	return attr;
	}

	Element* Element::FindChild(StringPiece ns, StringPiece name) {
	return FindChildWithAttribute(ns, name, {}, {}, {});
	}

	const Element* Element::FindChild(StringPiece ns, StringPiece name) const {
	return FindChildWithAttribute(ns, name, {}, {}, {});
	}

	Element* Element::FindChildWithAttribute(StringPiece ns, StringPiece name, StringPiece attr_ns,
	StringPiece attr_name, StringPiece attr_value) {
	return const_cast<Element>(static_cast<const Element>(this)->FindChildWithAttribute(
	ns, name, attr_ns, attr_name, attr_value));
	}

	const Element* Element::FindChildWithAttribute(StringPiece ns, StringPiece name,
	StringPiece attr_ns, StringPiece attr_name,
	StringPiece attr_value) const {
	for (const auto& child : children) {
	if (const Element* el = NodeCast<Element>(child.get())) {
	if (ns == el->namespace_uri && name == el->name) {
	if (attr_ns.empty() && attr_name.empty()) {
	return el;
	}

	const Attribute* attr = el->FindAttribute(attr_ns, attr_name);
	if (attr && attr_value == attr->value) {
	return el;
	}
	}
	}
	}
	return nullptr;
	}

	std::vector<Element*> Element::GetChildElements() {
	std::vector<Element*> elements;
	for (auto& child_node : children) {
	if (Element* child = NodeCast<Element>(child_node.get())) {
	elements.push_back(child);
	}
	}
	return elements;
	}

	std::unique_ptr<Node> Element::Clone(const ElementCloneFunc& el_cloner) const {
	auto el = util::make_unique<Element>();
	el->namespace_decls = namespace_decls;
	el->comment = comment;
	el->line_number = line_number;
	el->column_number = column_number;
	el->name = name;
	el->namespace_uri = namespace_uri;
	el->attributes.reserve(attributes.size());
	el_cloner(*this, el.get());
	el->children.reserve(children.size());
	for (const std::unique_ptr<xml::Node>& child : children) {
	el->AppendChild(child->Clone(el_cloner));
	}
	return std::move(el);
	}

	std::unique_ptr<Element> Element::CloneElement(const ElementCloneFunc& el_cloner) const {
	return std::unique_ptr<Element>(static_cast<Element*>(Clone(el_cloner).release()));
	}

	void Element::Accept(Visitor* visitor) {
	visitor->BeforeVisitElement(this);
	visitor->Visit(this);
	visitor->AfterVisitElement(this);
	}

	void Element::Accept(ConstVisitor* visitor) const {
	visitor->BeforeVisitElement(this);
	visitor->Visit(this);
	visitor->AfterVisitElement(this);
	}

	std::unique_ptr<Node> Text::Clone(const ElementCloneFunc&) const {
	auto t = util::make_unique<Text>();
	t->comment = comment;
	t->line_number = line_number;
	t->column_number = column_number;
	t->text = text;
	return std::move(t);
	}

	void Text::Accept(Visitor* visitor) {
	visitor->Visit(this);
	}

	void Text::Accept(ConstVisitor* visitor) const {
	visitor->Visit(this);
	}

	void PackageAwareVisitor::BeforeVisitElement(Element* el) {
	std::vector<PackageDecl> decls;
	for (const NamespaceDecl& decl : el->namespace_decls) {
	if (std::optional<ExtractedPackage> maybe_package = ExtractPackageFromNamespace(decl.uri)) {
	decls.push_back(PackageDecl{decl.prefix, std::move(maybe_package.value())});
	}
	}
	package_decls_.push_back(std::move(decls));
	}

	void PackageAwareVisitor::AfterVisitElement(Element* el) {
	package_decls_.pop_back();
	}

	std::optional<ExtractedPackage> PackageAwareVisitor::TransformPackageAlias(
	StringPiece alias) const {
	if (alias.empty()) {
	return ExtractedPackage{{}, false /private/};
	}

	const auto rend = package_decls_.rend();
	for (auto iter = package_decls_.rbegin(); iter != rend; ++iter) {
	const std::vector<PackageDecl>& decls = *iter;
	const auto rend2 = decls.rend();
	for (auto iter2 = decls.rbegin(); iter2 != rend2; ++iter2) {
	const PackageDecl& decl = *iter2;
	if (alias == decl.prefix) {
	if (decl.package.package.empty()) {
	return ExtractedPackage{{}, decl.package.private_namespace};
	}
	return decl.package;
	}
	}
	}
	return {};
	}

	} // namespace xml
	} // namespace aapt