using System;
using System.IO;
using System.Text;
using System.Xml;
using Google.ProtocolBuffers.Descriptors;
namespace Google.ProtocolBuffers.Serialization
{
/// <summary>
/// Writes a proto buffer to an XML document or fragment. .NET 3.5 users may also
/// use this class to produce Json by setting the options to support Json and providing
/// an XmlWriter obtained from <see cref="System.Runtime.Serialization.Json.JsonReaderWriterFactory"/>.
/// </summary>
public class XmlFormatWriter : AbstractTextWriter
{
public const string DefaultRootElementName = "root";
private const int NestedArrayFlag = 0x0001;
private readonly XmlWriter _output;
private string _rootElementName;
static XmlWriterSettings DefaultSettings(Encoding encoding)
{
return new XmlWriterSettings()
{
CheckCharacters = false,
NewLineHandling = NewLineHandling.Entitize,
OmitXmlDeclaration = true,
Encoding = encoding,
};
}
/// <summary>
/// Constructs the XmlFormatWriter to write to the given TextWriter
/// </summary>
public static XmlFormatWriter CreateInstance(TextWriter output) { return new XmlFormatWriter(XmlWriter.Create(output, DefaultSettings(output.Encoding))); }
/// <summary>
/// Constructs the XmlFormatWriter to write to the given stream
/// </summary>
public static XmlFormatWriter CreateInstance(Stream output) { return new XmlFormatWriter(XmlWriter.Create(output, DefaultSettings(Encoding.UTF8))); }
/// <summary>
/// Constructs the XmlFormatWriter to write to the given stream
/// </summary>
public static XmlFormatWriter CreateInstance(Stream output, Encoding encoding) { return new XmlFormatWriter(XmlWriter.Create(output, DefaultSettings(encoding))); }
/// <summary>
/// Constructs the XmlFormatWriter to write to the given XmlWriter
/// </summary>
public static XmlFormatWriter CreateInstance(XmlWriter output) { return new XmlFormatWriter(output); }
protected XmlFormatWriter(XmlWriter output)
{
_output = output;
_rootElementName = DefaultRootElementName;
}
/// <summary>
/// Closes the underlying XmlTextWriter
/// </summary>
protected override void Dispose(bool disposing)
{
if(disposing)
_output.Close();
}
/// <summary>
/// Gets or sets the default element name to use when using the Merge<TBuilder>()
/// </summary>
public string RootElementName
{
get { return _rootElementName; }
set { ThrowHelper.ThrowIfNull(value, "RootElementName"); _rootElementName = value; }
}
/// <summary>
/// Gets or sets the options to use while generating the XML
/// </summary>
public XmlWriterOptions Options { get; set; }
/// <summary>
/// Sets the options to use while generating the XML
/// </summary>
public XmlFormatWriter SetOptions(XmlWriterOptions options) { Options = options; return this; }
private bool TestOption(XmlWriterOptions option) { return (Options & option) != 0; }
/// <summary>
/// Writes a message as an element using the name defined in <see cref="RootElementName"/>
/// </summary>
public override void WriteMessage(IMessageLite message)
{ WriteMessage(_rootElementName, message); }
/// <summary>
/// Writes a message as an element with the given name
/// </summary>
public void WriteMessage(string elementName, IMessageLite message)
{
if (TestOption(XmlWriterOptions.OutputJsonTypes))
{
_output.WriteStartElement("root"); // json requires this is the root-element
_output.WriteAttributeString("type", "object");
}
else
_output.WriteStartElement(elementName);
message.WriteTo(this);
_output.WriteEndElement();
_output.Flush();
}
/// <summary>
/// Writes a message
/// </summary>
protected override void WriteMessageOrGroup(string field, IMessageLite message)
{
_output.WriteStartElement(field);
if (TestOption(XmlWriterOptions.OutputJsonTypes))
_output.WriteAttributeString("type", "object");
message.WriteTo(this);
_output.WriteEndElement();
}
/// <summary>
/// Writes a String value
/// </summary>
protected override void WriteAsText(string field, string textValue, object typedValue)
{
_output.WriteStartElement(field);
if (TestOption(XmlWriterOptions.OutputJsonTypes))
{
if (typedValue is int || typedValue is uint || typedValue is long || typedValue is ulong || typedValue is double || typedValue is float)
_output.WriteAttributeString("type", "number");
else if (typedValue is bool)
_output.WriteAttributeString("type", "boolean");
}
_output.WriteString(textValue);
//Empty strings should not be written as empty elements '<item/>', rather as '<item></item>'
if (_output.WriteState == WriteState.Element)
_output.WriteRaw("");
_output.WriteEndElement();
}
/// <summary>
/// Writes an array of field values
/// </summary>
protected override void WriteArray(FieldType fieldType, string field, System.Collections.IEnumerable items)
{
//see if it's empty
System.Collections.IEnumerator eitems = items.GetEnumerator();
try { if (!eitems.MoveNext()) return; }
finally
{ if (eitems is IDisposable) ((IDisposable) eitems).Dispose(); }
if (TestOption(XmlWriterOptions.OutputNestedArrays | XmlWriterOptions.OutputJsonTypes))
{
_output.WriteStartElement(field);
if (TestOption(XmlWriterOptions.OutputJsonTypes))
_output.WriteAttributeString("type", "array");
base.WriteArray(fieldType, "item", items);
_output.WriteEndElement();
}
else
base.WriteArray(fieldType, field, items);
}
/// <summary>
/// Writes a System.Enum by the numeric and textual value
/// </summary>
protected override void WriteEnum(string field, int number, string name)
{
_output.WriteStartElement(field);
if (!TestOption(XmlWriterOptions.OutputJsonTypes) && TestOption(XmlWriterOptions.OutputEnumValues))
_output.WriteAttributeString("value", XmlConvert.ToString(number));
_output.WriteString(name);
_output.WriteEndElement();
}
}
}