tools/aapt2/xml/XmlPullParser.h - 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.
  */

 #ifndef AAPT_XML_PULL_PARSER_H
 #define AAPT_XML_PULL_PARSER_H

 #include "Resource.h"
 #include "process/IResourceTableConsumer.h"
 #include "util/Maybe.h"
 #include "util/StringPiece.h"
 #include "xml/XmlUtil.h"

 #include <algorithm>
 #include <expat.h>
 #include <istream>
 #include <ostream>
 #include <queue>
 #include <stack>
 #include <string>
 #include <vector>

 namespace aapt {
 namespace xml {

 class XmlPullParser : public IPackageDeclStack {
 public:
     enum class Event {
         kBadDocument,
         kStartDocument,
         kEndDocument,

         kStartNamespace,
         kEndNamespace,
         kStartElement,
         kEndElement,
         kText,
         kComment,
     };

     /**
      * Skips to the next direct descendant node of the given startDepth,
      * skipping namespace nodes.
      *
      * When nextChildNode returns true, you can expect Comments, Text, and StartElement events.
      */
     static bool nextChildNode(XmlPullParser* parser, size_t startDepth);
     static bool skipCurrentElement(XmlPullParser* parser);
     static bool isGoodEvent(Event event);

     XmlPullParser(std::istream& in);
     ~XmlPullParser();

     /**
      * Returns the current event that is being processed.
      */
     Event getEvent() const;

     const std::string& getLastError() const;

     /**
      * Note, unlike XmlPullParser, the first call to next() will return
      * StartElement of the first element.
      */
     Event next();

     //
     // These are available for all nodes.
     //

     const std::u16string& getComment() const;
     size_t getLineNumber() const;
     size_t getDepth() const;

     /**
      * Returns the character data for a Text event.
      */
     const std::u16string& getText() const;

     //
     // Namespace prefix and URI are available for StartNamespace and EndNamespace.
     //

     const std::u16string& getNamespacePrefix() const;
     const std::u16string& getNamespaceUri() const;

     //
     // These are available for StartElement and EndElement.
     //

     const std::u16string& getElementNamespace() const;
     const std::u16string& getElementName() const;

     /*
      * Uses the current stack of namespaces to resolve the package. Eg:
      * xmlns:app = "http://schemas.android.com/apk/res/com.android.app"
      * ...
      * android:text="@app:string/message"
      *
      * In this case, 'app' will be converted to 'com.android.app'.
      *
      * If xmlns:app="http://schemas.android.com/apk/res-auto", then
      * 'package' will be set to 'defaultPackage'.
      */
     Maybe<ExtractedPackage> transformPackageAlias(
             const StringPiece16& alias, const StringPiece16& localPackage) const override;

     //
     // Remaining methods are for retrieving information about attributes
     // associated with a StartElement.
     //
     // Attributes must be in sorted order (according to the less than operator
     // of struct Attribute).
     //

     struct Attribute {
         std::u16string namespaceUri;
         std::u16string name;
         std::u16string value;

         int compare(const Attribute& rhs) const;
         bool operator<(const Attribute& rhs) const;
         bool operator==(const Attribute& rhs) const;
         bool operator!=(const Attribute& rhs) const;
     };

     using const_iterator = std::vector<Attribute>::const_iterator;

     const_iterator beginAttributes() const;
     const_iterator endAttributes() const;
     size_t getAttributeCount() const;
     const_iterator findAttribute(StringPiece16 namespaceUri, StringPiece16 name) const;

 private:
     static void XMLCALL startNamespaceHandler(void* userData, const char* prefix, const char* uri);
     static void XMLCALL startElementHandler(void* userData, const char* name, const char** attrs);
     static void XMLCALL characterDataHandler(void* userData, const char* s, int len);
     static void XMLCALL endElementHandler(void* userData, const char* name);
     static void XMLCALL endNamespaceHandler(void* userData, const char* prefix);
     static void XMLCALL commentDataHandler(void* userData, const char* comment);

     struct EventData {
         Event event;
         size_t lineNumber;
         size_t depth;
         std::u16string data1;
         std::u16string data2;
         std::vector<Attribute> attributes;
     };

     std::istream& mIn;
     XML_Parser mParser;
     char mBuffer[16384];
     std::queue<EventData> mEventQueue;
     std::string mLastError;
     const std::u16string mEmpty;
     size_t mDepth;
     std::stack<std::u16string> mNamespaceUris;

     struct PackageDecl {
         std::u16string prefix;
         ExtractedPackage package;
     };
     std::vector<PackageDecl> mPackageAliases;
 };

 /**
  * Finds the attribute in the current element within the global namespace.
  */
 Maybe<StringPiece16> findAttribute(const XmlPullParser* parser, const StringPiece16& name);

 /**
  * Finds the attribute in the current element within the global namespace. The attribute's value
  * must not be the empty string.
  */
 Maybe<StringPiece16> findNonEmptyAttribute(const XmlPullParser* parser, const StringPiece16& name);

 //
 // Implementation
 //

 inline ::std::ostream& operator<<(::std::ostream& out, XmlPullParser::Event event) {
     switch (event) {
         case XmlPullParser::Event::kBadDocument: return out << "BadDocument";
         case XmlPullParser::Event::kStartDocument: return out << "StartDocument";
         case XmlPullParser::Event::kEndDocument: return out << "EndDocument";
         case XmlPullParser::Event::kStartNamespace: return out << "StartNamespace";
         case XmlPullParser::Event::kEndNamespace: return out << "EndNamespace";
         case XmlPullParser::Event::kStartElement: return out << "StartElement";
         case XmlPullParser::Event::kEndElement: return out << "EndElement";
         case XmlPullParser::Event::kText: return out << "Text";
         case XmlPullParser::Event::kComment: return out << "Comment";
     }
     return out;
 }

 inline bool XmlPullParser::nextChildNode(XmlPullParser* parser, size_t startDepth) {
     Event event;

     // First get back to the start depth.
     while (isGoodEvent(event = parser->next()) && parser->getDepth() > startDepth + 1) {}

     // Now look for the first good node.
     while ((event != Event::kEndElement || parser->getDepth() > startDepth) && isGoodEvent(event)) {
         switch (event) {
         case Event::kText:
         case Event::kComment:
         case Event::kStartElement:
             return true;
         default:
             break;
         }
         event = parser->next();
     }
     return false;
 }

 inline bool XmlPullParser::skipCurrentElement(XmlPullParser* parser) {
     int depth = 1;
     while (depth > 0) {
         switch (parser->next()) {
             case Event::kEndDocument:
                 return true;
             case Event::kBadDocument:
                 return false;
             case Event::kStartElement:
                 depth++;
                 break;
             case Event::kEndElement:
                 depth--;
                 break;
             default:
                 break;
         }
     }
     return true;
 }

 inline bool XmlPullParser::isGoodEvent(XmlPullParser::Event event) {
     return event != Event::kBadDocument && event != Event::kEndDocument;
 }

 inline int XmlPullParser::Attribute::compare(const Attribute& rhs) const {
     int cmp = namespaceUri.compare(rhs.namespaceUri);
     if (cmp != 0) return cmp;
     return name.compare(rhs.name);
 }

 inline bool XmlPullParser::Attribute::operator<(const Attribute& rhs) const {
     return compare(rhs) < 0;
 }

 inline bool XmlPullParser::Attribute::operator==(const Attribute& rhs) const {
     return compare(rhs) == 0;
 }

 inline bool XmlPullParser::Attribute::operator!=(const Attribute& rhs) const {
     return compare(rhs) != 0;
 }

 inline XmlPullParser::const_iterator XmlPullParser::findAttribute(StringPiece16 namespaceUri,
                                                                   StringPiece16 name) const {
     const auto endIter = endAttributes();
     const auto iter = std::lower_bound(beginAttributes(), endIter,
             std::pair<StringPiece16, StringPiece16>(namespaceUri, name),
             [](const Attribute& attr, const std::pair<StringPiece16, StringPiece16>& rhs) -> bool {
                 int cmp = attr.namespaceUri.compare(0, attr.namespaceUri.size(),
                         rhs.first.data(), rhs.first.size());
                 if (cmp < 0) return true;
                 if (cmp > 0) return false;
                 cmp = attr.name.compare(0, attr.name.size(), rhs.second.data(), rhs.second.size());
                 if (cmp < 0) return true;
                 return false;
             }
     );

     if (iter != endIter && namespaceUri == iter->namespaceUri && name == iter->name) {
         return iter;
     }
     return endIter;
 }

 } // namespace xml
 } // namespace aapt

 #endif // AAPT_XML_PULL_PARSER_H
	/*
	* 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.
	*/

	#ifndef AAPT_XML_PULL_PARSER_H
	#define AAPT_XML_PULL_PARSER_H

	#include "Resource.h"
	#include "process/IResourceTableConsumer.h"
	#include "util/Maybe.h"
	#include "util/StringPiece.h"
	#include "xml/XmlUtil.h"

	#include <algorithm>
	#include <expat.h>
	#include <istream>
	#include <ostream>
	#include <queue>
	#include <stack>
	#include <string>
	#include <vector>

	namespace aapt {
	namespace xml {

	class XmlPullParser : public IPackageDeclStack {
	public:
	enum class Event {
	kBadDocument,
	kStartDocument,
	kEndDocument,

	kStartNamespace,
	kEndNamespace,
	kStartElement,
	kEndElement,
	kText,
	kComment,
	};

	/**
	* Skips to the next direct descendant node of the given startDepth,
	* skipping namespace nodes.
	*
	* When nextChildNode returns true, you can expect Comments, Text, and StartElement events.
	*/
	static bool nextChildNode(XmlPullParser* parser, size_t startDepth);
	static bool skipCurrentElement(XmlPullParser* parser);
	static bool isGoodEvent(Event event);

	XmlPullParser(std::istream& in);
	~XmlPullParser();

	/**
	* Returns the current event that is being processed.
	*/
	Event getEvent() const;

	const std::string& getLastError() const;

	/**
	* Note, unlike XmlPullParser, the first call to next() will return
	* StartElement of the first element.
	*/
	Event next();

	//
	// These are available for all nodes.
	//

	const std::u16string& getComment() const;
	size_t getLineNumber() const;
	size_t getDepth() const;

	/**
	* Returns the character data for a Text event.
	*/
	const std::u16string& getText() const;

	//
	// Namespace prefix and URI are available for StartNamespace and EndNamespace.
	//

	const std::u16string& getNamespacePrefix() const;
	const std::u16string& getNamespaceUri() const;

	//
	// These are available for StartElement and EndElement.
	//

	const std::u16string& getElementNamespace() const;
	const std::u16string& getElementName() const;

	/*
	* Uses the current stack of namespaces to resolve the package. Eg:
	* xmlns:app = "http://schemas.android.com/apk/res/com.android.app"
	* ...
	* android:text="@app:string/message"
	*
	* In this case, 'app' will be converted to 'com.android.app'.
	*
	* If xmlns:app="http://schemas.android.com/apk/res-auto", then
	* 'package' will be set to 'defaultPackage'.
	*/
	Maybe<ExtractedPackage> transformPackageAlias(
	const StringPiece16& alias, const StringPiece16& localPackage) const override;

	//
	// Remaining methods are for retrieving information about attributes
	// associated with a StartElement.
	//
	// Attributes must be in sorted order (according to the less than operator
	// of struct Attribute).
	//

	struct Attribute {
	std::u16string namespaceUri;
	std::u16string name;
	std::u16string value;

	int compare(const Attribute& rhs) const;
	bool operator<(const Attribute& rhs) const;
	bool operator==(const Attribute& rhs) const;
	bool operator!=(const Attribute& rhs) const;
	};

	using const_iterator = std::vector<Attribute>::const_iterator;

	const_iterator beginAttributes() const;
	const_iterator endAttributes() const;
	size_t getAttributeCount() const;
	const_iterator findAttribute(StringPiece16 namespaceUri, StringPiece16 name) const;

	private:
	static void XMLCALL startNamespaceHandler(void* userData, const char* prefix, const char* uri);
	static void XMLCALL startElementHandler(void* userData, const char* name, const char** attrs);
	static void XMLCALL characterDataHandler(void* userData, const char* s, int len);
	static void XMLCALL endElementHandler(void* userData, const char* name);
	static void XMLCALL endNamespaceHandler(void* userData, const char* prefix);
	static void XMLCALL commentDataHandler(void* userData, const char* comment);

	struct EventData {
	Event event;
	size_t lineNumber;
	size_t depth;
	std::u16string data1;
	std::u16string data2;
	std::vector<Attribute> attributes;
	};

	std::istream& mIn;
	XML_Parser mParser;
	char mBuffer[16384];
	std::queue<EventData> mEventQueue;
	std::string mLastError;
	const std::u16string mEmpty;
	size_t mDepth;
	std::stack<std::u16string> mNamespaceUris;

	struct PackageDecl {
	std::u16string prefix;
	ExtractedPackage package;
	};
	std::vector<PackageDecl> mPackageAliases;
	};

	/**
	* Finds the attribute in the current element within the global namespace.
	*/
	Maybe<StringPiece16> findAttribute(const XmlPullParser* parser, const StringPiece16& name);

	/**
	* Finds the attribute in the current element within the global namespace. The attribute's value
	* must not be the empty string.
	*/
	Maybe<StringPiece16> findNonEmptyAttribute(const XmlPullParser* parser, const StringPiece16& name);

	//
	// Implementation
	//

	inline ::std::ostream& operator<<(::std::ostream& out, XmlPullParser::Event event) {
	switch (event) {
	case XmlPullParser::Event::kBadDocument: return out << "BadDocument";
	case XmlPullParser::Event::kStartDocument: return out << "StartDocument";
	case XmlPullParser::Event::kEndDocument: return out << "EndDocument";
	case XmlPullParser::Event::kStartNamespace: return out << "StartNamespace";
	case XmlPullParser::Event::kEndNamespace: return out << "EndNamespace";
	case XmlPullParser::Event::kStartElement: return out << "StartElement";
	case XmlPullParser::Event::kEndElement: return out << "EndElement";
	case XmlPullParser::Event::kText: return out << "Text";
	case XmlPullParser::Event::kComment: return out << "Comment";
	}
	return out;
	}

	inline bool XmlPullParser::nextChildNode(XmlPullParser* parser, size_t startDepth) {
	Event event;

	// First get back to the start depth.
	while (isGoodEvent(event = parser->next()) && parser->getDepth() > startDepth + 1) {}

	// Now look for the first good node.
	while ((event != Event::kEndElement \|\| parser->getDepth() > startDepth) && isGoodEvent(event)) {
	switch (event) {
	case Event::kText:
	case Event::kComment:
	case Event::kStartElement:
	return true;
	default:
	break;
	}
	event = parser->next();
	}
	return false;
	}

	inline bool XmlPullParser::skipCurrentElement(XmlPullParser* parser) {
	int depth = 1;
	while (depth > 0) {
	switch (parser->next()) {
	case Event::kEndDocument:
	return true;
	case Event::kBadDocument:
	return false;
	case Event::kStartElement:
	depth++;
	break;
	case Event::kEndElement:
	depth--;
	break;
	default:
	break;
	}
	}
	return true;
	}

	inline bool XmlPullParser::isGoodEvent(XmlPullParser::Event event) {
	return event != Event::kBadDocument && event != Event::kEndDocument;
	}

	inline int XmlPullParser::Attribute::compare(const Attribute& rhs) const {
	int cmp = namespaceUri.compare(rhs.namespaceUri);
	if (cmp != 0) return cmp;
	return name.compare(rhs.name);
	}

	inline bool XmlPullParser::Attribute::operator<(const Attribute& rhs) const {
	return compare(rhs) < 0;
	}

	inline bool XmlPullParser::Attribute::operator==(const Attribute& rhs) const {
	return compare(rhs) == 0;
	}

	inline bool XmlPullParser::Attribute::operator!=(const Attribute& rhs) const {
	return compare(rhs) != 0;
	}

	inline XmlPullParser::const_iterator XmlPullParser::findAttribute(StringPiece16 namespaceUri,
	StringPiece16 name) const {
	const auto endIter = endAttributes();
	const auto iter = std::lower_bound(beginAttributes(), endIter,
	std::pair<StringPiece16, StringPiece16>(namespaceUri, name),
	[](const Attribute& attr, const std::pair<StringPiece16, StringPiece16>& rhs) -> bool {
	int cmp = attr.namespaceUri.compare(0, attr.namespaceUri.size(),
	rhs.first.data(), rhs.first.size());
	if (cmp < 0) return true;
	if (cmp > 0) return false;
	cmp = attr.name.compare(0, attr.name.size(), rhs.second.data(), rhs.second.size());
	if (cmp < 0) return true;
	return false;
	}
	);

	if (iter != endIter && namespaceUri == iter->namespaceUri && name == iter->name) {
	return iter;
	}
	return endIter;
	}

	} // namespace xml
	} // namespace aapt

	#endif // AAPT_XML_PULL_PARSER_H