blob: c1ee08c1a2c3a47b4dfd260368cdf081faf66942 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_LIBXML_CHROMIUM_LIBXML_UTILS_H_
#define THIRD_PARTY_LIBXML_CHROMIUM_LIBXML_UTILS_H_
#pragma once
#include <map>
#include <string>
#include "libxml/xmlreader.h"
#include "libxml/xmlwriter.h"
// libxml uses a global error function pointer for reporting errors.
// A ScopedXmlErrorFunc object lets you change the global error pointer
// for the duration of the object's lifetime.
class ScopedXmlErrorFunc {
public:
ScopedXmlErrorFunc(void* context, xmlGenericErrorFunc func) {
old_error_func_ = xmlGenericError;
old_error_context_ = xmlGenericErrorContext;
xmlSetGenericErrorFunc(context, func);
}
~ScopedXmlErrorFunc() {
xmlSetGenericErrorFunc(old_error_context_, old_error_func_);
}
private:
xmlGenericErrorFunc old_error_func_;
void* old_error_context_;
};
// XmlReader is a wrapper class around libxml's xmlReader,
// providing a simplified C++ API.
class XmlReader {
public:
XmlReader();
~XmlReader();
// Load a document into the reader from memory. |input| must be UTF-8 and
// exist for the lifetime of this object. Returns false on error.
// TODO(evanm): handle encodings other than UTF-8?
bool Load(const std::string& input);
// Load a document into the reader from a file. Returns false on error.
bool LoadFile(const std::string& file_path);
// Wrappers around libxml functions -----------------------------------------
// Read() advances to the next node. Returns false on EOF or error.
bool Read() { return xmlTextReaderRead(reader_) == 1; }
// Next(), when pointing at an opening tag, advances to the node after
// the matching closing tag. Returns false on EOF or error.
bool Next() { return xmlTextReaderNext(reader_) == 1; }
// Return the depth in the tree of the current node.
int Depth() { return xmlTextReaderDepth(reader_); }
// Returns the "local" name of the current node.
// For a tag like <foo:bar>, this is the string "bar".
std::string NodeName();
// Returns the name of the current node.
// For a tag like <foo:bar>, this is the string "foo:bar".
std::string NodeFullName();
// When pointing at a tag, retrieves the value of an attribute.
// Returns false on failure.
// E.g. for <foo bar:baz="a">, NodeAttribute("bar:baz", &value)
// returns true and |value| is set to "a".
bool NodeAttribute(const char* name, std::string* value);
// Populates |attributes| with all the attributes of the current tag and
// returns true. Note that namespace declarations are not reported.
// Returns false if there are no attributes in the current tag.
bool GetAllNodeAttributes(std::map<std::string, std::string>* attributes);
// Populates |namespaces| with all the namespaces (prefix/URI pairs) declared
// in the current tag and returns true. Note that the default namespace, if
// declared in the tag, is populated with an empty prefix.
// Returns false if there are no namespaces declared in the current tag.
bool GetAllDeclaredNamespaces(std::map<std::string, std::string>* namespaces);
// Sets |content| to the content of the current node if it is a #text/#cdata
// node.
// Returns true if the current node is a #text/#cdata node, false otherwise.
bool GetTextIfTextElement(std::string* content);
bool GetTextIfCDataElement(std::string* content);
// Returns true if the node is an element (e.g. <foo>). Note this returns
// false for self-closing elements (e.g. <foo/>). Use IsEmptyElement() to
// check for those.
bool IsElement();
// Returns true if the node is a closing element (e.g. </foo>).
bool IsClosingElement();
// Returns true if the current node is an empty (self-closing) element (e.g.
// <foo/>).
bool IsEmptyElement();
// Helper functions not provided by libxml ----------------------------------
// Return the string content within an element.
// "<foo>bar</foo>" is a sequence of three nodes:
// (1) open tag, (2) text, (3) close tag.
// With the reader currently at (1), this returns the text of (2),
// and advances past (3).
// Returns false on error.
bool ReadElementContent(std::string* content);
// Skip to the next opening tag, returning false if we reach a closing
// tag or EOF first.
// If currently on an opening tag, doesn't advance at all.
bool SkipToElement();
private:
// Returns the libxml node type of the current node.
int NodeType() { return xmlTextReaderNodeType(reader_); }
// The underlying libxml xmlTextReader.
xmlTextReaderPtr reader_;
};
// XmlWriter is a wrapper class around libxml's xmlWriter,
// providing a simplified C++ API.
// StartWriting must be called before other methods, and StopWriting
// must be called before GetWrittenString() will return results.
class XmlWriter {
public:
XmlWriter();
~XmlWriter();
// Allocates the xmlTextWriter and an xmlBuffer and starts an XML document.
// This must be called before any other functions. By default, indenting is
// set to true.
void StartWriting();
// Ends the XML document and frees the xmlTextWriter.
// This must be called before GetWrittenString() is called.
void StopWriting();
// Wrappers around libxml functions -----------------------------------------
// All following elements will be indented to match their depth.
void StartIndenting() { xmlTextWriterSetIndent(writer_, 1); }
// All follow elements will not be indented.
void StopIndenting() { xmlTextWriterSetIndent(writer_, 0); }
// Start an element with the given name. All future elements added will be
// children of this element, until it is ended. Returns false on error.
bool StartElement(const std::string& element_name) {
return xmlTextWriterStartElement(writer_,
BAD_CAST element_name.c_str()) >= 0;
}
// Ends the current open element. Returns false on error.
bool EndElement() {
return xmlTextWriterEndElement(writer_) >= 0;
}
// Appends to the content of the current open element.
bool AppendElementContent(const std::string& content) {
return xmlTextWriterWriteString(writer_,
BAD_CAST content.c_str()) >= 0;
}
// Adds an attribute to the current open element. Returns false on error.
bool AddAttribute(const std::string& attribute_name,
const std::string& attribute_value) {
return xmlTextWriterWriteAttribute(writer_,
BAD_CAST attribute_name.c_str(),
BAD_CAST attribute_value.c_str()) >= 0;
}
// Adds a new element with name |element_name| and content |content|
// to the buffer. Example: <|element_name|>|content|</|element_name|>
// Returns false on errors.
bool WriteElement(const std::string& element_name,
const std::string& content) {
return xmlTextWriterWriteElement(writer_,
BAD_CAST element_name.c_str(),
BAD_CAST content.c_str()) >= 0;
}
// Helper functions not provided by xmlTextWriter ---------------------------
// Returns the string that has been written to the buffer.
std::string GetWrittenString();
private:
// The underlying libxml xmlTextWriter.
xmlTextWriterPtr writer_;
// Stores the output.
xmlBufferPtr buffer_;
};
#endif // THIRD_PARTY_LIBXML_CHROMIUM_INCLUDE_LIBXML_LIBXML_UTILS_H_