dlls/webservices/writer.c

/*
 * Copyright 2015 Hans Leidekker for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <stdarg.h>

#include "windef.h"
#include "winbase.h"
#include "webservices.h"

#include "wine/debug.h"
#include "wine/list.h"
#include "webservices_private.h"

WINE_DEFAULT_DEBUG_CHANNEL(webservices);

static const struct
{
    ULONG size;
    BOOL  readonly;
}
writer_props[] =
{
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_MAX_DEPTH */
    { sizeof(BOOL), FALSE },        /* WS_XML_WRITER_PROPERTY_ALLOW_FRAGMENT */
    { sizeof(ULONG), FALSE },       /* WS_XML_READER_PROPERTY_MAX_ATTRIBUTES */
    { sizeof(BOOL), FALSE },        /* WS_XML_WRITER_PROPERTY_WRITE_DECLARATION */
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_INDENT */
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_BUFFER_TRIM_SIZE */
    { sizeof(WS_CHARSET), FALSE },  /* WS_XML_WRITER_PROPERTY_CHARSET */
    { sizeof(WS_BUFFERS), FALSE },  /* WS_XML_WRITER_PROPERTY_BUFFERS */
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_BUFFER_MAX_SIZE */
    { sizeof(WS_BYTES), FALSE },    /* WS_XML_WRITER_PROPERTY_BYTES */
    { sizeof(BOOL), TRUE },         /* WS_XML_WRITER_PROPERTY_IN_ATTRIBUTE */
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_MAX_MIME_PARTS_BUFFER_SIZE */
    { sizeof(WS_BYTES), FALSE },    /* WS_XML_WRITER_PROPERTY_INITIAL_BUFFER */
    { sizeof(BOOL), FALSE },        /* WS_XML_WRITER_PROPERTY_ALLOW_INVALID_CHARACTER_REFERENCES */
    { sizeof(ULONG), FALSE },       /* WS_XML_WRITER_PROPERTY_MAX_NAMESPACES */
    { sizeof(ULONG), TRUE },        /* WS_XML_WRITER_PROPERTY_BYTES_WRITTEN */
    { sizeof(ULONG), TRUE },        /* WS_XML_WRITER_PROPERTY_BYTES_TO_CLOSE */
    { sizeof(BOOL), FALSE },        /* WS_XML_WRITER_PROPERTY_COMPRESS_EMPTY_ELEMENTS */
    { sizeof(BOOL), FALSE }         /* WS_XML_WRITER_PROPERTY_EMIT_UNCOMPRESSED_EMPTY_ELEMENTS */
};

enum writer_state
{
    WRITER_STATE_INITIAL,
    WRITER_STATE_STARTELEMENT,
    WRITER_STATE_STARTENDELEMENT,
    WRITER_STATE_STARTATTRIBUTE,
    WRITER_STATE_ENDSTARTELEMENT,
    WRITER_STATE_ENDELEMENT
};

struct writer
{
    ULONG                     write_pos;
    char                     *write_bufptr;
    enum writer_state         state;
    struct node              *root;
    struct node              *current;
    WS_XML_STRING            *current_ns;
    WS_XML_WRITER_OUTPUT_TYPE output_type;
    struct xmlbuf            *output_buf;
    WS_HEAP                  *output_heap;
    ULONG                     prop_count;
    WS_XML_WRITER_PROPERTY    prop[sizeof(writer_props)/sizeof(writer_props[0])];
};

static struct writer *alloc_writer(void)
{
    static const ULONG count = sizeof(writer_props)/sizeof(writer_props[0]);
    struct writer *ret;
    ULONG i, size = sizeof(*ret) + count * sizeof(WS_XML_WRITER_PROPERTY);
    char *ptr;

    for (i = 0; i < count; i++) size += writer_props[i].size;
    if (!(ret = heap_alloc_zero( size ))) return NULL;

    ptr = (char *)&ret->prop[count];
    for (i = 0; i < count; i++)
    {
        ret->prop[i].value = ptr;
        ret->prop[i].valueSize = writer_props[i].size;
        ptr += ret->prop[i].valueSize;
    }
    ret->prop_count = count;
    return ret;
}

static HRESULT set_writer_prop( struct writer *writer, WS_XML_WRITER_PROPERTY_ID id, const void *value,
                                ULONG size )
{
    if (id >= writer->prop_count || size != writer_props[id].size || writer_props[id].readonly)
        return E_INVALIDARG;

    memcpy( writer->prop[id].value, value, size );
    return S_OK;
}

static HRESULT get_writer_prop( struct writer *writer, WS_XML_WRITER_PROPERTY_ID id, void *buf, ULONG size )
{
    if (id >= writer->prop_count || size != writer_props[id].size)
        return E_INVALIDARG;

    memcpy( buf, writer->prop[id].value, writer->prop[id].valueSize );
    return S_OK;
}

static void free_writer( struct writer *writer )
{
    destroy_nodes( writer->root );
    heap_free( writer->current_ns );
    WsFreeHeap( writer->output_heap );
    heap_free( writer );
}

static void write_insert_eof( struct writer *writer, struct node *eof )
{
    if (!writer->root) writer->root = eof;
    else
    {
        eof->parent = writer->root;
        list_add_tail( &writer->root->children, &eof->entry );
    }
    writer->current = eof;
}

static void write_insert_bof( struct writer *writer, struct node *bof )
{
    writer->root->parent = bof;
    list_add_tail( &bof->children, &writer->root->entry );
    writer->current = writer->root = bof;
}

static void write_insert_node( struct writer *writer, struct node *node )
{
    node->parent = writer->current;
    if (writer->current == writer->root)
    {
        struct list *eof = list_tail( &writer->root->children );
        list_add_before( eof, &node->entry );
    }
    else list_add_tail( &writer->current->children, &node->entry );
    writer->current = node;
}

static HRESULT write_init_state( struct writer *writer )
{
    struct node *node;

    heap_free( writer->current_ns );
    writer->current_ns = NULL;
    destroy_nodes( writer->root );
    writer->root = NULL;

    if (!(node = alloc_node( WS_XML_NODE_TYPE_EOF ))) return E_OUTOFMEMORY;
    write_insert_eof( writer, node );
    writer->state = WRITER_STATE_INITIAL;
    return S_OK;
}

/**************************************************************************
 *          WsCreateWriter		[webservices.@]
 */
HRESULT WINAPI WsCreateWriter( const WS_XML_WRITER_PROPERTY *properties, ULONG count,
                               WS_XML_WRITER **handle, WS_ERROR *error )
{
    struct writer *writer;
    ULONG i, max_depth = 32, max_attrs = 128, trim_size = 4096, max_size = 65536, max_ns = 32;
    WS_CHARSET charset = WS_CHARSET_UTF8;
    HRESULT hr;

    TRACE( "%p %u %p %p\n", properties, count, handle, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!handle) return E_INVALIDARG;
    if (!(writer = alloc_writer())) return E_OUTOFMEMORY;

    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_MAX_DEPTH, &max_depth, sizeof(max_depth) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_MAX_ATTRIBUTES, &max_attrs, sizeof(max_attrs) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_BUFFER_TRIM_SIZE, &trim_size, sizeof(trim_size) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_CHARSET, &charset, sizeof(charset) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_BUFFER_MAX_SIZE, &max_size, sizeof(max_size) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_MAX_MIME_PARTS_BUFFER_SIZE, &max_size, sizeof(max_size) );
    set_writer_prop( writer, WS_XML_WRITER_PROPERTY_MAX_NAMESPACES, &max_ns, sizeof(max_ns) );

    for (i = 0; i < count; i++)
    {
        hr = set_writer_prop( writer, properties[i].id, properties[i].value, properties[i].valueSize );
        if (hr != S_OK)
        {
            free_writer( writer );
            return hr;
        }
    }

    hr = get_writer_prop( writer, WS_XML_WRITER_PROPERTY_BUFFER_MAX_SIZE, &max_size, sizeof(max_size) );
    if (hr != S_OK)
    {
        free_writer( writer );
        return hr;
    }

    hr = WsCreateHeap( max_size, 0, NULL, 0, &writer->output_heap, NULL );
    if (hr != S_OK)
    {
        free_writer( writer );
        return hr;
    }

    hr = write_init_state( writer );
    if (hr != S_OK)
    {
        free_writer( writer );
        return hr;
    }

    *handle = (WS_XML_WRITER *)writer;
    return S_OK;
}

/**************************************************************************
 *          WsFreeWriter		[webservices.@]
 */
void WINAPI WsFreeWriter( WS_XML_WRITER *handle )
{
    struct writer *writer = (struct writer *)handle;

    TRACE( "%p\n", handle );
    free_writer( writer );
}

#define XML_BUFFER_INITIAL_ALLOCATED_SIZE 256
static struct xmlbuf *alloc_xmlbuf( WS_HEAP *heap )
{
    struct xmlbuf *ret;

    if (!(ret = ws_alloc( heap, sizeof(*ret) ))) return NULL;
    if (!(ret->ptr = ws_alloc( heap, XML_BUFFER_INITIAL_ALLOCATED_SIZE )))
    {
        ws_free( heap, ret );
        return NULL;
    }
    ret->heap           = heap;
    ret->size_allocated = XML_BUFFER_INITIAL_ALLOCATED_SIZE;
    ret->size           = 0;
    return ret;
}

static void free_xmlbuf( struct xmlbuf *xmlbuf )
{
    if (!xmlbuf) return;
    ws_free( xmlbuf->heap, xmlbuf->ptr );
    ws_free( xmlbuf->heap, xmlbuf );
}

/**************************************************************************
 *          WsCreateXmlBuffer		[webservices.@]
 */
HRESULT WINAPI WsCreateXmlBuffer( WS_HEAP *heap, const WS_XML_BUFFER_PROPERTY *properties,
                                  ULONG count, WS_XML_BUFFER **handle, WS_ERROR *error )
{
    struct xmlbuf *xmlbuf;

    if (!heap || !handle) return E_INVALIDARG;
    if (count) FIXME( "properties not implemented\n" );

    if (!(xmlbuf = alloc_xmlbuf( heap ))) return E_OUTOFMEMORY;

    *handle = (WS_XML_BUFFER *)xmlbuf;
    return S_OK;
}

/**************************************************************************
 *          WsGetWriterProperty		[webservices.@]
 */
HRESULT WINAPI WsGetWriterProperty( WS_XML_WRITER *handle, WS_XML_WRITER_PROPERTY_ID id,
                                    void *buf, ULONG size, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;

    TRACE( "%p %u %p %u %p\n", handle, id, buf, size, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer->output_type) return WS_E_INVALID_OPERATION;

    switch (id)
    {
    case WS_XML_WRITER_PROPERTY_BYTES:
    {
        WS_BYTES *bytes = buf;
        if (size != sizeof(*bytes)) return E_INVALIDARG;
        bytes->bytes  = writer->output_buf->ptr;
        bytes->length = writer->output_buf->size;
        return S_OK;
    }
    default:
        return get_writer_prop( writer, id, buf, size );
    }
}

static void set_output_buffer( struct writer *writer, struct xmlbuf *xmlbuf )
{
    /* free current buffer if it's ours */
    if (writer->output_buf && writer->output_buf->heap == writer->output_heap)
    {
        free_xmlbuf( writer->output_buf );
    }
    writer->output_buf   = xmlbuf;
    writer->output_type  = WS_XML_WRITER_OUTPUT_TYPE_BUFFER;
    writer->write_bufptr = xmlbuf->ptr;
    writer->write_pos    = 0;
}

/**************************************************************************
 *          WsSetOutput		[webservices.@]
 */
HRESULT WINAPI WsSetOutput( WS_XML_WRITER *handle, const WS_XML_WRITER_ENCODING *encoding,
                            const WS_XML_WRITER_OUTPUT *output, const WS_XML_WRITER_PROPERTY *properties,
                            ULONG count, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    struct node *node;
    HRESULT hr;
    ULONG i;

    TRACE( "%p %p %p %p %u %p\n", handle, encoding, output, properties, count, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer) return E_INVALIDARG;

    for (i = 0; i < count; i++)
    {
        hr = set_writer_prop( writer, properties[i].id, properties[i].value, properties[i].valueSize );
        if (hr != S_OK) return hr;
    }

    if ((hr = write_init_state( writer )) != S_OK) return hr;

    switch (encoding->encodingType)
    {
    case WS_XML_WRITER_ENCODING_TYPE_TEXT:
    {
        WS_XML_WRITER_TEXT_ENCODING *text = (WS_XML_WRITER_TEXT_ENCODING *)encoding;
        if (text->charSet != WS_CHARSET_UTF8)
        {
            FIXME( "charset %u not supported\n", text->charSet );
            return E_NOTIMPL;
        }
        break;
    }
    default:
        FIXME( "encoding type %u not supported\n", encoding->encodingType );
        return E_NOTIMPL;
    }
    switch (output->outputType)
    {
    case WS_XML_WRITER_OUTPUT_TYPE_BUFFER:
    {
        struct xmlbuf *xmlbuf;

        if (!(xmlbuf = alloc_xmlbuf( writer->output_heap ))) return E_OUTOFMEMORY;
        set_output_buffer( writer, xmlbuf );
        break;
    }
    default:
        FIXME( "output type %u not supported\n", output->outputType );
        return E_NOTIMPL;
    }

    if (!(node = alloc_node( WS_XML_NODE_TYPE_BOF ))) return E_OUTOFMEMORY;
    write_insert_bof( writer, node );
    return S_OK;
}

/**************************************************************************
 *          WsSetOutputToBuffer		[webservices.@]
 */
HRESULT WINAPI WsSetOutputToBuffer( WS_XML_WRITER *handle, WS_XML_BUFFER *buffer,
                                    const WS_XML_WRITER_PROPERTY *properties, ULONG count,
                                    WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    struct xmlbuf *xmlbuf = (struct xmlbuf *)buffer;
    struct node *node;
    HRESULT hr;
    ULONG i;

    TRACE( "%p %p %p %u %p\n", handle, buffer, properties, count, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer || !xmlbuf) return E_INVALIDARG;

    for (i = 0; i < count; i++)
    {
        hr = set_writer_prop( writer, properties[i].id, properties[i].value, properties[i].valueSize );
        if (hr != S_OK) return hr;
    }

    if ((hr = write_init_state( writer )) != S_OK) return hr;
    set_output_buffer( writer, xmlbuf );

    if (!(node = alloc_node( WS_XML_NODE_TYPE_BOF ))) return E_OUTOFMEMORY;
    write_insert_bof( writer, node );
    return S_OK;
}

static HRESULT write_grow_buffer( struct writer *writer, ULONG size )
{
    struct xmlbuf *buf = writer->output_buf;
    SIZE_T new_size;
    void *tmp;

    if (buf->size_allocated >= writer->write_pos + size)
    {
        buf->size = writer->write_pos + size;
        return S_OK;
    }
    new_size = max( buf->size_allocated * 2, writer->write_pos + size );
    if (!(tmp = ws_realloc( buf->heap, buf->ptr, new_size ))) return E_OUTOFMEMORY;
    writer->write_bufptr = buf->ptr = tmp;
    buf->size_allocated = new_size;
    buf->size = writer->write_pos + size;
    return S_OK;
}

static inline void write_char( struct writer *writer, char ch )
{
    writer->write_bufptr[writer->write_pos++] = ch;
}

static inline void write_bytes( struct writer *writer, const BYTE *bytes, ULONG len )
{
    memcpy( writer->write_bufptr + writer->write_pos, bytes, len );
    writer->write_pos += len;
}

static HRESULT write_attribute( struct writer *writer, WS_XML_ATTRIBUTE *attr )
{
    WS_XML_UTF8_TEXT *text = (WS_XML_UTF8_TEXT *)attr->value;
    ULONG size;
    HRESULT hr;

    /* ' prefix:attr="value"' */

    size = attr->localName->length + 4 /* ' =""' */;
    if (attr->prefix) size += attr->prefix->length + 1 /* ':' */;
    if (text) size += text->value.length;
    if ((hr = write_grow_buffer( writer, size )) != S_OK) return hr;

    write_char( writer, ' ' );
    if (attr->prefix)
    {
        write_bytes( writer, attr->prefix->bytes, attr->prefix->length );
        write_char( writer, ':' );
    }
    write_bytes( writer, attr->localName->bytes, attr->localName->length );
    write_char( writer, '=' );
    if (attr->singleQuote) write_char( writer, '\'' );
    else write_char( writer, '"' );
    if (text) write_bytes( writer, text->value.bytes, text->value.length );
    if (attr->singleQuote) write_char( writer, '\'' );
    else write_char( writer, '"' );

    /* FIXME: ignoring namespace */
    return S_OK;
}

static inline BOOL is_current_namespace( struct writer *writer, const WS_XML_STRING *ns )
{
    return (WsXmlStringEquals( writer->current_ns, ns, NULL ) == S_OK);
}

static HRESULT set_current_namespace( struct writer *writer, const WS_XML_STRING *ns )
{
    WS_XML_STRING *str;
    if (!(str = alloc_xml_string( (const char *)ns->bytes, ns->length ))) return E_OUTOFMEMORY;
    heap_free( writer->current_ns );
    writer->current_ns = str;
    return S_OK;
}

static HRESULT write_startelement( struct writer *writer )
{
    WS_XML_ELEMENT_NODE *elem = (WS_XML_ELEMENT_NODE *)writer->current;
    ULONG size, i;
    HRESULT hr;

    /* '<prefix:localname prefix:attr="value"... xmlns:prefix="ns"' */

    size = elem->localName->length + 1 /* '<' */;
    if (elem->prefix) size += elem->prefix->length + 1 /* ':' */;
    if (elem->ns->length && !is_current_namespace( writer, elem->ns ))
    {
        size += strlen(" xmlns") + elem->ns->length + 3 /* '=""' */;
        if (elem->prefix) size += elem->prefix->length + 1 /* ':' */;
    }
    if ((hr = write_grow_buffer( writer, size )) != S_OK) return hr;

    write_char( writer, '<' );
    if (elem->prefix)
    {
        write_bytes( writer, elem->prefix->bytes, elem->prefix->length );
        write_char( writer, ':' );
    }
    write_bytes( writer, elem->localName->bytes, elem->localName->length );
    for (i = 0; i < elem->attributeCount; i++)
    {
        if ((hr = write_attribute( writer, elem->attributes[i] )) != S_OK) return hr;
    }
    if (elem->ns->length && !is_current_namespace( writer, elem->ns ))
    {
        if ((hr = set_current_namespace( writer, elem->ns )) != S_OK) return hr;

        write_bytes( writer, (const BYTE *)" xmlns", 6 );
        if (elem->prefix)
        {
            write_char( writer, ':' );
            write_bytes( writer, elem->prefix->bytes, elem->prefix->length );
        }
        write_char( writer, '=' );
        write_char( writer, '"' );
        write_bytes( writer, elem->ns->bytes, elem->ns->length );
        write_char( writer, '"' );
    }
    return S_OK;
}

static HRESULT write_endelement( struct writer *writer )
{
    WS_XML_ELEMENT_NODE *elem = (WS_XML_ELEMENT_NODE *)writer->current;
    ULONG size;
    HRESULT hr;

    /* '</prefix:localname>' */

    size = elem->localName->length + 3 /* '</>' */;
    if (elem->prefix) size += elem->prefix->length + 1 /* ':' */;
    if ((hr = write_grow_buffer( writer, size )) != S_OK) return hr;

    write_char( writer, '<' );
    write_char( writer, '/' );
    if (elem->prefix)
    {
        write_bytes( writer, elem->prefix->bytes, elem->prefix->length );
        write_char( writer, ':' );
    }
    write_bytes( writer, elem->localName->bytes, elem->localName->length );
    write_char( writer, '>' );
    return S_OK;
}

/**************************************************************************
 *          WsWriteEndAttribute		[webservices.@]
 */
HRESULT WINAPI WsWriteEndAttribute( WS_XML_WRITER *handle, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;

    TRACE( "%p %p\n", handle, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer) return E_INVALIDARG;
    if (writer->state != WRITER_STATE_STARTATTRIBUTE) return WS_E_INVALID_OPERATION;

    writer->state = WRITER_STATE_STARTELEMENT;
    return S_OK;
}

/**************************************************************************
 *          WsWriteEndElement		[webservices.@]
 */
HRESULT WINAPI WsWriteEndElement( WS_XML_WRITER *handle, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    HRESULT hr;

    TRACE( "%p %p\n", handle, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer) return E_INVALIDARG;

    if (writer->state == WRITER_STATE_STARTELEMENT)
    {
        /* '/>' */
        if ((hr = write_startelement( writer )) != S_OK) return hr;
        if ((hr = write_grow_buffer( writer, 2 )) != S_OK) return hr;
        write_char( writer, '/' );
        write_char( writer, '>' );

        writer->current = writer->current->parent;
        writer->state   = WRITER_STATE_STARTENDELEMENT;
        return S_OK;
    }
    else
    {
        struct node *node = alloc_node( WS_XML_NODE_TYPE_END_ELEMENT );
        if (!node) return E_OUTOFMEMORY;

        /* '</prefix:localname>' */
        if ((hr = write_endelement( writer )) != S_OK)
        {
            free_node( node );
            return hr;
        }

        write_insert_node( writer, node );
        writer->current = node->parent;
        writer->state   = WRITER_STATE_ENDELEMENT;
        return S_OK;
    }
    return WS_E_INVALID_OPERATION;
}

/**************************************************************************
 *          WsWriteEndStartElement		[webservices.@]
 */
HRESULT WINAPI WsWriteEndStartElement( WS_XML_WRITER *handle, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    HRESULT hr;

    TRACE( "%p %p\n", handle, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer) return E_INVALIDARG;
    if (writer->state != WRITER_STATE_STARTELEMENT) return WS_E_INVALID_OPERATION;

    if ((hr = write_startelement( writer )) != S_OK) return hr;
    if ((hr = write_grow_buffer( writer, 1 )) != S_OK) return hr;
    write_char( writer, '>' );

    writer->state = WRITER_STATE_ENDSTARTELEMENT;
    return S_OK;
}

/**************************************************************************
 *          WsWriteStartAttribute		[webservices.@]
 */
HRESULT WINAPI WsWriteStartAttribute( WS_XML_WRITER *handle, const WS_XML_STRING *prefix,
                                      const WS_XML_STRING *localname, const WS_XML_STRING *ns,
                                      BOOL single, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    WS_XML_ELEMENT_NODE *elem;
    WS_XML_ATTRIBUTE *attr;
    HRESULT hr = E_OUTOFMEMORY;

    TRACE( "%p %s %s %s %d %p\n", handle, debugstr_xmlstr(prefix), debugstr_xmlstr(localname),
           debugstr_xmlstr(ns), single, error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer || !localname || !ns) return E_INVALIDARG;

    if (writer->state != WRITER_STATE_STARTELEMENT) return WS_E_INVALID_OPERATION;
    elem = (WS_XML_ELEMENT_NODE *)writer->current;

    if (!(attr = heap_alloc_zero( sizeof(*attr) ))) return E_OUTOFMEMORY;
    attr->singleQuote = !!single;

    if (prefix && !(attr->prefix = alloc_xml_string( (const char *)prefix->bytes, prefix->length )))
        goto error;

    if (!(attr->localName = alloc_xml_string( (const char *)localname->bytes, localname->length )))
        goto error;

    if (!(attr->ns = alloc_xml_string( (const char *)ns->bytes, ns->length )))
        goto error;

    if ((hr = append_attribute( elem, attr )) != S_OK) goto error;

    writer->state = WRITER_STATE_STARTATTRIBUTE;
    return S_OK;

error:
    free_attribute( attr );
    return hr;
}

/**************************************************************************
 *          WsWriteStartElement		[webservices.@]
 */
HRESULT WINAPI WsWriteStartElement( WS_XML_WRITER *handle, const WS_XML_STRING *prefix,
                                    const WS_XML_STRING *localname, const WS_XML_STRING *ns,
                                    WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    struct node *node;
    WS_XML_ELEMENT_NODE *elem;
    HRESULT hr = E_OUTOFMEMORY;

    TRACE( "%p %s %s %s %p\n", handle, debugstr_xmlstr(prefix), debugstr_xmlstr(localname),
           debugstr_xmlstr(ns), error );
    if (error) FIXME( "ignoring error parameter\n" );

    if (!writer || !localname || !ns) return E_INVALIDARG;

    /* flush current start element */
    if (writer->state == WRITER_STATE_STARTELEMENT)
    {
        if ((hr = write_startelement( writer )) != S_OK) return hr;
        if ((hr = write_grow_buffer( writer, 1 )) != S_OK) return hr;
        write_char( writer, '>' );
    }

    if (!(node = alloc_node( WS_XML_NODE_TYPE_ELEMENT ))) return E_OUTOFMEMORY;
    elem = (WS_XML_ELEMENT_NODE *)node;

    if (prefix && !(elem->prefix = alloc_xml_string( (const char *)prefix->bytes, prefix->length )))
        goto error;

    if (!(elem->localName = alloc_xml_string( (const char *)localname->bytes, localname->length )))
        goto error;

    if (!(elem->ns = alloc_xml_string( (const char *)ns->bytes, ns->length )))
        goto error;

    write_insert_node( writer, node );
    writer->state = WRITER_STATE_STARTELEMENT;
    return S_OK;

error:
    free_node( node );
    return hr;
}

/**************************************************************************
 *          WsWriteText		[webservices.@]
 */
HRESULT WINAPI WsWriteText( WS_XML_WRITER *handle, const WS_XML_TEXT *text, WS_ERROR *error )
{
    struct writer *writer = (struct writer *)handle;
    WS_XML_ELEMENT_NODE *elem;
    WS_XML_UTF8_TEXT *src, *dst;

    TRACE( "%p %p %p\n", handle, text, error );

    if (!writer || !text) return E_INVALIDARG;

    if (writer->state != WRITER_STATE_STARTATTRIBUTE)
    {
        FIXME( "can't handle writer state %u\n", writer->state );
        return E_NOTIMPL;
    }
    if (text->textType != WS_XML_TEXT_TYPE_UTF8)
    {
        FIXME( "text type %u not supported\n", text->textType );
        return E_NOTIMPL;
    }
    src = (WS_XML_UTF8_TEXT *)text;
    if (!(dst = alloc_utf8_text( (const char *)src->value.bytes, src->value.length )))
        return E_OUTOFMEMORY;

    elem = (WS_XML_ELEMENT_NODE *)writer->current;
    elem->attributes[elem->attributeCount - 1]->value = (WS_XML_TEXT *)dst;
    return S_OK;
}