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/*
* 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 <expat.h>
#include <algorithm>
#include <istream>
#include <ostream>
#include <queue>
#include <stack>
#include <string>
#include <vector>
#include "android-base/macros.h"
#include "androidfw/StringPiece.h"
#include "Resource.h"
#include "io/Io.h"
#include "process/IResourceTableConsumer.h"
#include "util/Maybe.h"
#include "xml/XmlUtil.h"
namespace aapt {
namespace xml {
class XmlPullParser : public IPackageDeclStack {
public:
enum class Event {
kBadDocument,
kStartDocument,
kEndDocument,
kStartNamespace,
kEndNamespace,
kStartElement,
kEndElement,
kText,
kComment,
kCdataStart,
kCdataEnd,
};
/**
* Skips to the next direct descendant node of the given start_depth,
* skipping namespace nodes.
*
* When NextChildNode() returns true, you can expect Comments, Text, and
* StartElement events.
*/
static bool NextChildNode(XmlPullParser* parser, size_t start_depth);
static bool SkipCurrentElement(XmlPullParser* parser);
static bool IsGoodEvent(Event event);
explicit XmlPullParser(io::InputStream* in);
~XmlPullParser();
/**
* Returns the current event that is being processed.
*/
Event event() const;
const std::string& error() 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::string& comment() const;
size_t line_number() const;
size_t depth() const;
/**
* Returns the character data for a Text event.
*/
const std::string& text() const;
//
// Namespace prefix and URI are available for StartNamespace and EndNamespace.
//
const std::string& namespace_prefix() const;
const std::string& namespace_uri() const;
//
// These are available for StartElement and EndElement.
//
const std::string& element_namespace() const;
const std::string& element_name() 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 android::StringPiece& alias) const override;
struct PackageDecl {
std::string prefix;
ExtractedPackage package;
};
const std::vector<PackageDecl>& package_decls() const;
//
// 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::string namespace_uri;
std::string name;
std::string 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 begin_attributes() const;
const_iterator end_attributes() const;
size_t attribute_count() const;
const_iterator FindAttribute(android::StringPiece namespace_uri, android::StringPiece name) const;
private:
DISALLOW_COPY_AND_ASSIGN(XmlPullParser);
static void XMLCALL StartNamespaceHandler(void* user_data, const char* prefix,
const char* uri);
static void XMLCALL StartElementHandler(void* user_data, const char* name,
const char** attrs);
static void XMLCALL CharacterDataHandler(void* user_data, const char* s,
int len);
static void XMLCALL EndElementHandler(void* user_data, const char* name);
static void XMLCALL EndNamespaceHandler(void* user_data, const char* prefix);
static void XMLCALL CommentDataHandler(void* user_data, const char* comment);
static void XMLCALL StartCdataSectionHandler(void* user_data);
static void XMLCALL EndCdataSectionHandler(void* user_data);
struct EventData {
Event event;
size_t line_number;
size_t depth;
std::string data1;
std::string data2;
std::vector<Attribute> attributes;
};
io::InputStream* in_;
XML_Parser parser_;
std::queue<EventData> event_queue_;
std::string error_;
const std::string empty_;
size_t depth_;
std::stack<std::string> namespace_uris_;
std::vector<PackageDecl> package_aliases_;
};
/**
* Finds the attribute in the current element within the global namespace.
*/
Maybe<android::StringPiece> FindAttribute(const XmlPullParser* parser,
const android::StringPiece& name);
/**
* Finds the attribute in the current element within the global namespace. The
* attribute's value
* must not be the empty string.
*/
Maybe<android::StringPiece> FindNonEmptyAttribute(const XmlPullParser* parser,
const android::StringPiece& 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";
case XmlPullParser::Event::kCdataStart:
return out << "CdataStart";
case XmlPullParser::Event::kCdataEnd:
return out << "CdataEnd";
}
return out;
}
inline bool XmlPullParser::NextChildNode(XmlPullParser* parser, size_t start_depth) {
Event event;
// First get back to the start depth.
while (IsGoodEvent(event = parser->Next()) && parser->depth() > start_depth + 1) {
}
// Now look for the first good node.
while ((event != Event::kEndElement || parser->depth() > start_depth) && IsGoodEvent(event)) {
switch (event) {
case Event::kText:
case Event::kComment:
case Event::kStartElement:
case Event::kCdataStart:
case Event::kCdataEnd:
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 = namespace_uri.compare(rhs.namespace_uri);
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(
android::StringPiece namespace_uri, android::StringPiece name) const {
const auto end_iter = end_attributes();
const auto iter = std::lower_bound(
begin_attributes(), end_iter,
std::pair<android::StringPiece, android::StringPiece>(namespace_uri, name),
[](const Attribute& attr,
const std::pair<android::StringPiece, android::StringPiece>& rhs) -> bool {
int cmp = attr.namespace_uri.compare(
0, attr.namespace_uri.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 != end_iter && namespace_uri == iter->namespace_uri &&
name == iter->name) {
return iter;
}
return end_iter;
}
} // namespace xml
} // namespace aapt
#endif // AAPT_XML_PULL_PARSER_H