/*	$NetBSD: prop_object.c,v 1.39 2025/04/26 17:13:23 thorpej Exp $	*/

/*-
 * Copyright (c) 2006, 2007, 2025 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "prop_object_impl.h"
#include <prop/prop_object.h>

#ifdef _PROP_NEED_REFCNT_MTX
static pthread_mutex_t _prop_refcnt_mtx = PTHREAD_MUTEX_INITIALIZER;
#endif /* _PROP_NEED_REFCNT_MTX */

#if !defined(_KERNEL) && !defined(_STANDALONE)
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#endif

#ifdef _STANDALONE
void *
_prop_standalone_calloc(size_t size)
{
	void *rv;

	rv = alloc(size);
	if (rv != NULL)
		memset(rv, 0, size);

	return (rv);
}

void *
_prop_standalone_realloc(void *v, size_t size)
{
	void *rv;

	rv = alloc(size);
	if (rv != NULL) {
		memcpy(rv, v, size);	/* XXX */
		dealloc(v, 0);		/* XXX */
	}

	return (rv);
}
#endif /* _STANDALONE */

/*
 * _prop_object_init --
 *	Initialize an object.  Called when sub-classes create
 *	an instance.
 */
void
_prop_object_init(struct _prop_object *po, const struct _prop_object_type *pot)
{

	po->po_type = pot;
	po->po_refcnt = 1;
}

/*
 * _prop_object_fini --
 *	Finalize an object.  Called when sub-classes destroy
 *	an instance.
 */
/*ARGSUSED*/
void
_prop_object_fini(struct _prop_object *po _PROP_ARG_UNUSED)
{
	/* Nothing to do, currently. */
}

/*
 * _prop_object_externalize_start_line --
 *	Append the start-of-line character sequence.
 */
bool
_prop_object_externalize_start_line(
    struct _prop_object_externalize_context *ctx)
{
	unsigned int i;

	for (i = 0; i < ctx->poec_depth; i++) {
		if (_prop_object_externalize_append_char(ctx, '\t') == false) {
			return false;
		}
	}
	return true;
}

/*
 * _prop_object_externalize_end_line --
 *	Append the end-of-line character sequence.
 */
bool
_prop_object_externalize_end_line(
    struct _prop_object_externalize_context *ctx, const char *trailer)
{
	if (trailer != NULL &&
	    _prop_object_externalize_append_cstring(ctx, trailer) == false) {
		return false;
	}
	return _prop_object_externalize_append_char(ctx, '\n');
}

/*
 * _prop_object_externalize_start_tag --
 *	Append an item's start tag to the externalize buffer.
 */
bool
_prop_object_externalize_start_tag(
    struct _prop_object_externalize_context *ctx,
    const struct _prop_object_type_tags *tags,
    const char *tagattrs)
{
	bool rv;

	_PROP_ASSERT(ctx->poec_format == PROP_FORMAT_XML ||
		     ctx->poec_format == PROP_FORMAT_JSON);

	switch (ctx->poec_format) {
	case PROP_FORMAT_JSON:
		rv = tags->json_open_tag == NULL ||
		     _prop_object_externalize_append_cstring(ctx,
							tags->json_open_tag);
		break;

	default:		/* XML */
		rv = _prop_object_externalize_append_char(ctx, '<') &&
		     _prop_object_externalize_append_cstring(ctx,
							     tags->xml_tag) &&
		     (tagattrs == NULL ||
		      (_prop_object_externalize_append_char(ctx, ' ') &&
		       _prop_object_externalize_append_cstring(ctx,
							       tagattrs))) &&
		     _prop_object_externalize_append_char(ctx, '>');
		break;
	}

	return rv;
}

/*
 * _prop_object_externalize_end_tag --
 *	Append an item's end tag to the externalize buffer.
 */
bool
_prop_object_externalize_end_tag(
    struct _prop_object_externalize_context *ctx,
    const struct _prop_object_type_tags *tags)
{
	bool rv;

	_PROP_ASSERT(ctx->poec_format == PROP_FORMAT_XML ||
		     ctx->poec_format == PROP_FORMAT_JSON);

	switch (ctx->poec_format) {
	case PROP_FORMAT_JSON:
		rv = tags->json_close_tag == NULL ||
		     _prop_object_externalize_append_cstring(ctx,
							tags->json_close_tag);
		break;
	
	default:		/* XML */
		rv = _prop_object_externalize_append_char(ctx, '<') &&
		     _prop_object_externalize_append_char(ctx, '/') &&
		     _prop_object_externalize_append_cstring(ctx,
							     tags->xml_tag) &&
		     _prop_object_externalize_append_char(ctx, '>');
		break;
	}

	return rv;
}

/*
 * _prop_object_externalize_empty_tag --
 *	Append an item's empty tag to the externalize buffer.
 */
bool
_prop_object_externalize_empty_tag(
    struct _prop_object_externalize_context *ctx,
    const struct _prop_object_type_tags *tags)
{
	bool rv;

	_PROP_ASSERT(ctx->poec_format == PROP_FORMAT_XML ||
		     ctx->poec_format == PROP_FORMAT_JSON);

	switch (ctx->poec_format) {
	case PROP_FORMAT_JSON:
		if (tags->json_open_tag == NULL ||
		    _prop_object_externalize_append_cstring(ctx,
					tags->json_open_tag) == false) {
			return false;
		}
		if (tags->json_empty_sep != NULL &&
		    _prop_object_externalize_append_cstring(ctx,
					tags->json_empty_sep) == false) {
			return false;
		}
		if (tags->json_close_tag != NULL) {
			rv = _prop_object_externalize_append_cstring(ctx,
							tags->json_close_tag);
		} else {
			rv = true;
		}
		break;

	default:		/* XML */
		rv = _prop_object_externalize_append_char(ctx, '<') &&
		     _prop_object_externalize_append_cstring(ctx,
							     tags->xml_tag) &&
		     _prop_object_externalize_append_char(ctx, '/') &&
		     _prop_object_externalize_append_char(ctx, '>');
		break;
	}

	return rv;
}

/*
 * _prop_object_externalize_append_cstring --
 *	Append a C string to the externalize buffer.
 */
bool
_prop_object_externalize_append_cstring(
    struct _prop_object_externalize_context *ctx, const char *cp)
{

	while (*cp != '\0') {
		if (_prop_object_externalize_append_char(ctx,
						(unsigned char) *cp) == false)
			return (false);
		cp++;
	}

	return (true);
}

/*
 * _prop_object_externalize_append_encoded_cstring --
 *	Append an encoded C string to the externalize buffer.
 */
static bool
_prop_object_externalize_append_encoded_cstring_xml(
    struct _prop_object_externalize_context *ctx, const char *cp)
{

	while (*cp != '\0') {
		switch (*cp) {
		case '<':
			if (_prop_object_externalize_append_cstring(ctx,
					"&lt;") == false)
				return (false);
			break;
		case '>':
			if (_prop_object_externalize_append_cstring(ctx,
					"&gt;") == false)
				return (false);
			break;
		case '&':
			if (_prop_object_externalize_append_cstring(ctx,
					"&amp;") == false)
				return (false);
			break;
		default:
			if (_prop_object_externalize_append_char(ctx,
					(unsigned char) *cp) == false)
				return (false);
			break;
		}
		cp++;
	}

	return (true);
}

static bool
_prop_object_externalize_append_escu(
    struct _prop_object_externalize_context *ctx, uint16_t val)
{
	char tmpstr[sizeof("\\uXXXX")];

	snprintf(tmpstr, sizeof(tmpstr), "\\u%04X", val);
	return _prop_object_externalize_append_cstring(ctx, tmpstr);
}

static bool
_prop_object_externalize_append_encoded_cstring_json(
    struct _prop_object_externalize_context *ctx, const char *cp)
{
	bool esc;
	unsigned char ch;

	while ((ch = *cp) != '\0') {
		esc = true;
		switch (ch) {
		/*
		 * First, the two explicit exclusions.  They must be
		 * escaped.
		 */
		case '"':	/* U+0022 quotation mark */
			goto emit;

		case '\\':	/* U+005C reverse solidus */
			goto emit;

		/*
		 * And some special cases that are explcit in the grammar.
		 */
		case '/':	/* U+002F solidus (XXX this one seems silly) */
			goto emit;

		case 0x08:	/* U+0008 backspace */
			ch = 'b';
			goto emit;

		case 0x0c:	/* U+000C form feed */
			ch = 'f';
			goto emit;

		case 0x0a:	/* U+000A line feed */
			ch = 'n';
			goto emit;

		case 0x0d:	/* U+000D carriage return */
			ch = 'r';
			goto emit;

		case 0x09:	/* U+0009 tab */
			ch = 't';
			goto emit;

		default:
			/*
			 * \u-escape all other single-byte ASCII control
			 * characters, per RFC 8259:
			 *
			 * <quote>
			 * All Unicode characters may be placed within the
			 * quotation marks, except for the characters that
			 * MUST be escaped: quotation mark, reverse solidus,
			 * and the control characters (U+0000 through U+001F).
			 * </quote>
			 */
			if (ch < 0x20) {
				if (_prop_object_externalize_append_escu(ctx,
							ch) == false) {
					return false;
				}
				break;
			}
			/*
			 * We're going to just treat everything else like
			 * UTF-8 (we've been handed a C-string, after all)
			 * and pretend it will all be OK.
			 */
			esc = false;
		emit:
			if ((esc && _prop_object_externalize_append_char(ctx,
							'\\') == false) ||
			    _prop_object_externalize_append_char(ctx,
							ch) == false) {
				return false;
			}
			break;
		}
		cp++;
	}

	return true;
}

bool
_prop_object_externalize_append_encoded_cstring(
    struct _prop_object_externalize_context *ctx, const char *cp)
{
	_PROP_ASSERT(ctx->poec_format == PROP_FORMAT_XML ||
		     ctx->poec_format == PROP_FORMAT_JSON);

	switch (ctx->poec_format) {
	case PROP_FORMAT_JSON:
		return _prop_object_externalize_append_encoded_cstring_json(ctx,
									    cp);
	default:
		return _prop_object_externalize_append_encoded_cstring_xml(ctx,
									   cp);
	}
}

#define	BUF_EXPAND		256

/*
 * _prop_object_externalize_append_char --
 *	Append a single character to the externalize buffer.
 */
bool
_prop_object_externalize_append_char(
    struct _prop_object_externalize_context *ctx, unsigned char c)
{

	_PROP_ASSERT(ctx->poec_capacity != 0);
	_PROP_ASSERT(ctx->poec_buf != NULL);
	_PROP_ASSERT(ctx->poec_len <= ctx->poec_capacity);

	if (ctx->poec_len == ctx->poec_capacity) {
		char *cp = _PROP_REALLOC(ctx->poec_buf,
					 ctx->poec_capacity + BUF_EXPAND,
					 M_TEMP);
		if (cp == NULL)
			return (false);
		ctx->poec_capacity = ctx->poec_capacity + BUF_EXPAND;
		ctx->poec_buf = cp;
	}

	ctx->poec_buf[ctx->poec_len++] = c;

	return (true);
}

static const struct _prop_object_type_tags _plist_type_tags = {
	.xml_tag	=	"plist",
};

/*
 * _prop_object_externalize_header --
 *	Append the standard XML header to the externalize buffer.
 */
bool
_prop_object_externalize_header(struct _prop_object_externalize_context *ctx)
{
	static const char _plist_xml_header[] =
"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
"<!DOCTYPE plist PUBLIC \"-//Apple Computer//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n";

	if (ctx->poec_format != PROP_FORMAT_XML) {
		return true;
	}

	if (_prop_object_externalize_append_cstring(ctx,
						 _plist_xml_header) == false ||
	    _prop_object_externalize_start_tag(ctx,
	    				&_plist_type_tags,
					"version=\"1.0\"") == false ||
	    _prop_object_externalize_append_char(ctx, '\n') == false)
		return (false);

	return (true);
}

/*
 * _prop_object_externalize_footer --
 *	Append the standard XML footer to the externalize buffer.  This
 *	also NUL-terminates the buffer.
 */
bool
_prop_object_externalize_footer(struct _prop_object_externalize_context *ctx)
{
	if (_prop_object_externalize_end_line(ctx, NULL) == false) {
		return false;
	}

	if (ctx->poec_format == PROP_FORMAT_XML) {
		if (_prop_object_externalize_end_tag(ctx,
					&_plist_type_tags) == false ||
		    _prop_object_externalize_end_line(ctx, NULL) == false) {
			return false;
		}
	}

	return _prop_object_externalize_append_char(ctx, '\0');
}

/*
 * _prop_object_externalize_context_alloc --
 *	Allocate an externalize context.
 */
struct _prop_object_externalize_context *
_prop_object_externalize_context_alloc(prop_format_t fmt)
{
	struct _prop_object_externalize_context *ctx;

	ctx = _PROP_MALLOC(sizeof(*ctx), M_TEMP);
	if (ctx != NULL) {
		ctx->poec_buf = _PROP_MALLOC(BUF_EXPAND, M_TEMP);
		if (ctx->poec_buf == NULL) {
			_PROP_FREE(ctx, M_TEMP);
			return (NULL);
		}
		ctx->poec_len = 0;
		ctx->poec_capacity = BUF_EXPAND;
		ctx->poec_depth = 0;
		ctx->poec_format = fmt;
	}
	return (ctx);
}

/*
 * _prop_object_externalize_context_free --
 *	Free an externalize context.
 */
void
_prop_object_externalize_context_free(
		struct _prop_object_externalize_context *ctx)
{

	/* Buffer is always freed by the caller. */
	_PROP_FREE(ctx, M_TEMP);
}

/*
 * _prop_object_externalize --
 *	Externalize an object, returning a NUL-terminated buffer
 *	containing the serialized data in either XML or JSON format.
 *	The buffer is allocated with the M_TEMP memory type.
 */
char *
_prop_object_externalize(struct _prop_object *obj, prop_format_t fmt)
{
	struct _prop_object_externalize_context *ctx;
	char *cp = NULL;

	if (obj == NULL || obj->po_type->pot_extern == NULL) {
		return NULL;
	}
	if (fmt != PROP_FORMAT_XML && fmt != PROP_FORMAT_JSON) {
		return NULL;
	}

	ctx = _prop_object_externalize_context_alloc(fmt);
	if (ctx == NULL) {
		return NULL;
	}

	if (_prop_object_externalize_header(ctx) == false ||
	    obj->po_type->pot_extern(ctx, obj) == false ||
	    _prop_object_externalize_footer(ctx) == false) {
		/* We are responsible for releasing the buffer. */
		_PROP_FREE(ctx->poec_buf, M_TEMP);
		goto bad;
	}

	cp = ctx->poec_buf;
 bad:
	_prop_object_externalize_context_free(ctx);
	return cp;
}

/*
 * _prop_object_internalize_skip_comment --
 *	Skip the body and end tag of a comment.
 */
static bool
_prop_object_internalize_skip_comment(
				struct _prop_object_internalize_context *ctx)
{
	const char *cp = ctx->poic_cp;

	while (!_PROP_EOF(*cp)) {
		if (cp[0] == '-' &&
		    cp[1] == '-' &&
		    cp[2] == '>') {
			ctx->poic_cp = cp + 3;
			return (true);
		}
		cp++;
	}

	return (false);		/* ran out of buffer */
}

/*
 * _prop_object_internalize_find_tag --
 *	Find the next tag in an XML stream.  Optionally compare the found
 *	tag to an expected tag name.  State of the context is undefined
 *	if this routine returns false.  Upon success, the context points
 *	to the first octet after the tag.
 */
bool
_prop_object_internalize_find_tag(struct _prop_object_internalize_context *ctx,
		      const char *tag, _prop_tag_type_t type)
{
	const char *cp;
	size_t taglen;

	if (tag != NULL)
		taglen = strlen(tag);
	else
		taglen = 0;

 start_over:
	cp = ctx->poic_cp;

	/*
	 * Find the start of the tag.
	 */
	cp = _prop_object_internalize_skip_whitespace(cp);
	if (*cp != '<')
		return (false);

	ctx->poic_tag_start = cp++;
	if (_PROP_EOF(*cp))
		return (false);

	if (*cp == '!') {
		if (cp[1] != '-' || cp[2] != '-')
			return (false);
		/*
		 * Comment block -- only allowed if we are allowed to
		 * return a start tag.
		 */
		if (type == _PROP_TAG_TYPE_END)
			return (false);
		ctx->poic_cp = cp + 3;
		if (_prop_object_internalize_skip_comment(ctx) == false)
			return (false);
		goto start_over;
	}

	if (*cp == '/') {
		if (type != _PROP_TAG_TYPE_END &&
		    type != _PROP_TAG_TYPE_EITHER)
			return (false);
		cp++;
		if (_PROP_EOF(*cp))
			return (false);
		ctx->poic_tag_type = _PROP_TAG_TYPE_END;
	} else {
		if (type != _PROP_TAG_TYPE_START &&
		    type != _PROP_TAG_TYPE_EITHER)
			return (false);
		ctx->poic_tag_type = _PROP_TAG_TYPE_START;
	}

	ctx->poic_tagname = cp;

	while (!_PROP_ISSPACE(*cp) && *cp != '/' && *cp != '>') {
		if (_PROP_EOF(*cp))
			return (false);
		cp++;
	}

	ctx->poic_tagname_len = cp - ctx->poic_tagname;

	/* Make sure this is the tag we're looking for. */
	if (tag != NULL &&
	    (taglen != ctx->poic_tagname_len ||
	     memcmp(tag, ctx->poic_tagname, taglen) != 0))
		return (false);

	/* Check for empty tag. */
	if (*cp == '/') {
		if (ctx->poic_tag_type != _PROP_TAG_TYPE_START)
			return(false);		/* only valid on start tags */
		ctx->poic_is_empty_element = true;
		cp++;
		if (_PROP_EOF(*cp) || *cp != '>')
			return (false);
	} else
		ctx->poic_is_empty_element = false;

	/* Easy case of no arguments. */
	if (*cp == '>') {
		ctx->poic_tagattr = NULL;
		ctx->poic_tagattr_len = 0;
		ctx->poic_tagattrval = NULL;
		ctx->poic_tagattrval_len = 0;
		ctx->poic_cp = cp + 1;
		return (true);
	}

	_PROP_ASSERT(!_PROP_EOF(*cp));
	cp++;
	if (_PROP_EOF(*cp))
		return (false);

	cp = _prop_object_internalize_skip_whitespace(cp);
	if (_PROP_EOF(*cp))
		return (false);

	ctx->poic_tagattr = cp;

	while (!_PROP_ISSPACE(*cp) && *cp != '=') {
		if (_PROP_EOF(*cp))
			return (false);
		cp++;
	}

	ctx->poic_tagattr_len = cp - ctx->poic_tagattr;

	cp++;
	if (*cp != '\"')
		return (false);
	cp++;
	if (_PROP_EOF(*cp))
		return (false);

	ctx->poic_tagattrval = cp;
	while (*cp != '\"') {
		if (_PROP_EOF(*cp))
			return (false);
		cp++;
	}
	ctx->poic_tagattrval_len = cp - ctx->poic_tagattrval;

	cp++;
	if (*cp != '>')
		return (false);

	ctx->poic_cp = cp + 1;
	return (true);
}

/*
 * _prop_object_internalize_decode_string --
 *	Decode an encoded string.
 */

#define	ADDCHAR(x)							\
	do {								\
		if (target) {						\
			if (tarindex >= targsize) {			\
				return false;				\
			}						\
			target[tarindex] = (x);				\
		}							\
		tarindex++;						\
	} while (/*CONSTCOND*/0)

static bool
_prop_object_internalize_decode_string_xml(
				struct _prop_object_internalize_context *ctx,
				char *target, size_t targsize, size_t *sizep,
				const char **cpp)
{
	const char *src;
	size_t tarindex;
	char c;

	tarindex = 0;
	src = ctx->poic_cp;

	for (;;) {
		if (_PROP_EOF(*src))
			return (false);
		if (*src == '<') {
			break;
		}

		if ((c = *src) == '&') {
			if (src[1] == 'a' &&
			    src[2] == 'm' &&
			    src[3] == 'p' &&
			    src[4] == ';') {
			    	c = '&';
				src += 5;
			} else if (src[1] == 'l' &&
				   src[2] == 't' &&
				   src[3] == ';') {
				c = '<';
				src += 4;
			} else if (src[1] == 'g' &&
				   src[2] == 't' &&
				   src[3] == ';') {
				c = '>';
				src += 4;
			} else if (src[1] == 'a' &&
				   src[2] == 'p' &&
				   src[3] == 'o' &&
				   src[4] == 's' &&
				   src[5] == ';') {
				c = '\'';
				src += 6;
			} else if (src[1] == 'q' &&
				   src[2] == 'u' &&
				   src[3] == 'o' &&
				   src[4] == 't' &&
				   src[5] == ';') {
				c = '\"';
				src += 6;
			} else
				return (false);
		} else
			src++;
		ADDCHAR(c);
	}

	_PROP_ASSERT(*src == '<');
	if (sizep != NULL)
		*sizep = tarindex;
	if (cpp != NULL)
		*cpp = src;

	return (true);
}

static unsigned int
_prop_object_decode_string_uesc_getu16(const char *src, unsigned int idx,
    uint16_t *valp)
{
	unsigned int i;
	uint16_t val;
	unsigned char c;

	if (src[idx] != '\\' || src[idx + 1] != 'u') {
		return 0;
	}

	for (val = 0, i = 2; i < 6; i++) {
		val <<= 4;
		c = src[idx + i];
		if (c >= 'A' && c <= 'F') {
			val |= 10 + (c - 'A');
		} else if (c >= 'a' && c <= 'f') {
			val |= 10 + (c - 'a');
		} else if (c >= '0' && c <= '9') {
			val |= c - '0';
		} else {
			return 0;
		}
	}

	*valp = val;
	return idx + i;
}

#define	HS_FIRST	0xd800
#define	HS_LAST		0xdbff
#define	HS_SHIFT	10
#define	LS_FIRST	0xdc00
#define	LS_LAST		0xdfff

#define	HIGH_SURROGAGE_P(x)	\
	((x) >= HS_FIRST && (x) <= HS_LAST)
#define	LOW_SURROGATE_P(x)	\
	((x) >= LS_FIRST && (x) <= LS_LAST)
#define	SURROGATE_P(x)		\
	(HIGH_SURROGAGE_P(x) || LOW_SURROGATE_P(x))

static int
_prop_object_decode_string_uesc(const char *src, char *c,
    unsigned int *cszp)
{
	unsigned int idx = 0;
	uint32_t code;
	uint16_t code16[2] = { 0, 0 };

	idx = _prop_object_decode_string_uesc_getu16(src, idx, &code16[0]);
	if (idx == 0) {
		return 0;
	}
	if (! SURROGATE_P(code16[0])) {
		/* Simple case: not a surrogate pair */
		code = code16[0];
	} else if (HIGH_SURROGAGE_P(code16[0])) {
		idx = _prop_object_decode_string_uesc_getu16(src, idx,
							     &code16[1]);
		if (idx == 0) {
			return 0;
		}
		/* Next code must be the low surrogate. */
		if (! LOW_SURROGATE_P(code16[1])) {
			return 0;
		}
		code = (((uint32_t)code16[0] - HS_FIRST) << HS_SHIFT) +
		        (          code16[1] - LS_FIRST)              +
		       0x10000;
	} else {
		/* Got the low surrogate first; this is an error. */
		return 0;
	}

	/*
	 * Ok, we have the code point.  Now convert it to UTF-8.
	 * First we'll just split into nybbles.
	 */
	uint8_t u = (code >> 20) & 0xf;
	uint8_t v = (code >> 16) & 0xf;
	uint8_t w = (code >> 12) & 0xf;
	uint8_t x = (code >>  8) & 0xf;
	uint8_t y = (code >>  4) & 0xf;
	uint8_t z = (code      ) & 0xf;

	/*
	 * ...and swizzle the nybbles accordingly.
	 *
	 * N.B. we expcitly disallow inserting a NUL into the string
	 * by way of a \uXXXX escape.
	 */
	if (code == 0) {
		/* Not allowed. */
		return 0;
	} else if (/*code >= 0x0000 &&*/ code <= 0x007f) {
		c[0] = (char)code;	/* == (y << 4) | z */
		*cszp = 1;
	} else if (/*code >= 0x0080 &&*/ code <= 0x07ff) {
		c[0] = 0xc0 | (x << 2) | (y >> 2);
		c[1] = 0x80 | ((y & 3) << 4) | z;
		*cszp = 2;
	} else if (/*code >= 0x0800 &&*/ code <= 0xffff) {
		c[0] = 0xe0 | w;
		c[1] = 0x80 | (x << 2) | (y >> 2);
		c[2] = 0x80 | ((y & 3) << 4) | z;
		*cszp = 3;
	} else if (/*code >= 0x010000 &&*/ code <= 0x10ffff) {
		c[0] = 0xf0 | ((u & 1) << 2) | (v >> 2);
		c[1] = 0x80 | ((v & 3) << 4) | w;
		c[2] = 0x80 | (x << 2) | (y >> 2);
		c[3] = 0x80 | ((y & 3) << 4) | z;
		*cszp = 4;
	} else {
		/* Invalid code. */
		return 0;
	}

	return idx;	/* advance input by this much */
}

#undef HS_FIRST
#undef HS_LAST
#undef LS_FIRST
#undef LS_LAST
#undef HIGH_SURROGAGE_P
#undef LOW_SURROGATE_P
#undef SURROGATE_P

static bool
_prop_object_internalize_decode_string_json(
				struct _prop_object_internalize_context *ctx,
				char *target, size_t targsize, size_t *sizep,
				const char **cpp)
{
	const char *src;
	size_t tarindex;
	char c[4];
	unsigned int csz;

	tarindex = 0;
	src = ctx->poic_cp;

	for (;;) {
		if (_PROP_EOF(*src)) {
			return false;
		}
		if (*src == '"') {
			break;
		}

		csz = 1;
		if ((c[0] = *src) == '\\') {
			int advance = 2;

			switch ((c[0] = src[1])) {
			case '"':		/* quotation mark */
			case '\\':		/* reverse solidus */
			case '/':		/* solidus */
				/* identity mapping */
				break;

			case 'b':		/* backspace */
				c[0] = 0x08;
				break;

			case 'f':		/* form feed */
				c[0] = 0x0c;
				break;

			case 'n':		/* line feed */
				c[0] = 0x0a;
				break;

			case 'r':		/* carriage return */
				c[0] = 0x0d;
				break;

			case 't':		/* tab */
				c[0] = 0x09;
				break;

			case 'u':
				advance = _prop_object_decode_string_uesc(
				    src, c, &csz);
				if (advance == 0) {
					return false;
				}
				break;

			default:
				/* invalid escape */
				return false;
			}
			src += advance;
		} else {
			src++;
		}
		for (unsigned int i = 0; i < csz; i++) {
			ADDCHAR(c[i]);
		}
	}

	_PROP_ASSERT(*src == '"');
	if (sizep != NULL) {
		*sizep = tarindex;
	}
	if (cpp != NULL) {
		*cpp = src;
	}

	return true;
}

#undef ADDCHAR

bool
_prop_object_internalize_decode_string(
				struct _prop_object_internalize_context *ctx,
				char *target, size_t targsize, size_t *sizep,
				const char **cpp)
{
	_PROP_ASSERT(ctx->poic_format == PROP_FORMAT_XML ||
		     ctx->poic_format == PROP_FORMAT_JSON);

	switch (ctx->poic_format) {
	case PROP_FORMAT_JSON:
		return _prop_object_internalize_decode_string_json(ctx,
		    target, targsize, sizep, cpp);

	default:		/* XML */
		return _prop_object_internalize_decode_string_xml(ctx,
		    target, targsize, sizep, cpp);
	}
}

/*
 * _prop_object_internalize_skip_whitespace --
 *	Skip a span of whitespace.
 */
const char *
_prop_object_internalize_skip_whitespace(const char *cp)
{
	while (_PROP_ISSPACE(*cp)) {
		cp++;
	}
	return cp;
}

/*
 * _prop_object_internalize_match --
 *	Returns true if the two character streams match.
 */
bool
_prop_object_internalize_match(const char *str1, size_t len1,
			       const char *str2, size_t len2)
{

	return (len1 == len2 && memcmp(str1, str2, len1) == 0);
}

#define	INTERNALIZER(t, f)			\
{	t,	sizeof(t) - 1,		f	}

static const struct _prop_object_internalizer {
	const char			*poi_tag;
	size_t				poi_taglen;
	prop_object_internalizer_t	poi_intern;
} _prop_object_internalizer_table[] = {
	INTERNALIZER("array", _prop_array_internalize),

	INTERNALIZER("true", _prop_bool_internalize),
	INTERNALIZER("false", _prop_bool_internalize),

	INTERNALIZER("data", _prop_data_internalize),

	INTERNALIZER("dict", _prop_dictionary_internalize),

	INTERNALIZER("integer", _prop_number_internalize),

	INTERNALIZER("string", _prop_string_internalize),

	{ 0, 0, NULL }
};

#undef INTERNALIZER

/*
 * _prop_object_internalize_by_tag --
 *	Determine the object type from the tag in the context and
 *	internalize it.
 */
static prop_object_t
_prop_object_internalize_by_tag(struct _prop_object_internalize_context *ctx)
{
	const struct _prop_object_internalizer *poi;
	prop_object_t obj, parent_obj;
	void *data, *iter;
	prop_object_internalizer_continue_t iter_func;
	struct _prop_stack stack;

	_prop_stack_init(&stack);

 match_start:
	for (poi = _prop_object_internalizer_table;
	     poi->poi_tag != NULL; poi++) {
		if (_prop_object_internalize_match(ctx->poic_tagname,
						   ctx->poic_tagname_len,
						   poi->poi_tag,
						   poi->poi_taglen))
			break;
	}
	if ((poi == NULL) || (poi->poi_tag == NULL)) {
		while (_prop_stack_pop(&stack, &obj, &iter, &data, NULL)) {
			iter_func = (prop_object_internalizer_continue_t)iter;
			(*iter_func)(&stack, &obj, ctx, data, NULL);
		}

		return (NULL);
	}

	obj = NULL;
	if (!(*poi->poi_intern)(&stack, &obj, ctx))
		goto match_start;

	parent_obj = obj;
	while (_prop_stack_pop(&stack, &parent_obj, &iter, &data, NULL)) {
		iter_func = (prop_object_internalizer_continue_t)iter;
		if (!(*iter_func)(&stack, &parent_obj, ctx, data, obj))
			goto match_start;
		obj = parent_obj;
	}

	return (parent_obj);
}

/*
 * _prop_object_internalize_xml --
 *	Internalize a property list from XML data.
 */
static prop_object_t
_prop_object_internalize_xml(struct _prop_object_internalize_context *ctx,
    const struct _prop_object_type_tags *initial_tag)
{
	prop_object_t obj = NULL;

	/* We start with a <plist> tag. */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_START) == false)
		goto out;

	/* Plist elements cannot be empty. */
	if (ctx->poic_is_empty_element)
		goto out;

	/*
	 * We don't understand any plist attributes, but Apple XML
	 * property lists often have a "version" attribute.  If we
	 * see that one, we simply ignore it.
	 */
	if (ctx->poic_tagattr != NULL &&
	    !_PROP_TAGATTR_MATCH(ctx, "version"))
		goto out;

	/* Next we expect to see opening master_tag. */
	if (_prop_object_internalize_find_tag(ctx,
				initial_tag != NULL ? initial_tag->xml_tag
			      			    : NULL,
				_PROP_TAG_TYPE_START) == false)
		goto out;

	obj = _prop_object_internalize_by_tag(ctx);
	if (obj == NULL)
		goto out;

	/*
	 * We've advanced past the closing main tag.
	 * Now we want </plist>.
	 */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_END) == false) {
		prop_object_release(obj);
		obj = NULL;
	}

 out:
	return (obj);
}

/*
 * _prop_object_internalize_json --
 *	Internalize a property list from JSON data.
 */
static prop_object_t
_prop_object_internalize_json(struct _prop_object_internalize_context *ctx,
    const struct _prop_object_type_tags *initial_tag __unused)
{
	prop_object_t obj, parent_obj;
	void *data, *iter;
	prop_object_internalizer_continue_t iter_func;
	struct _prop_stack stack;
	bool (*intern)(prop_stack_t, prop_object_t *,
		       struct _prop_object_internalize_context *);

	_prop_stack_init(&stack);

 match_start:
	intern = NULL;
	ctx->poic_tagname = ctx->poic_tagattr = ctx->poic_tagattrval = NULL;
	ctx->poic_tagname_len = ctx->poic_tagattr_len =
	    ctx->poic_tagattrval_len = 0;
	ctx->poic_is_empty_element = false;
	ctx->poic_cp = _prop_object_internalize_skip_whitespace(ctx->poic_cp);
	switch (ctx->poic_cp[0]) {
	case '{':
		ctx->poic_cp++;
		intern = _prop_dictionary_internalize;
		break;

	case '[':
		ctx->poic_cp++;
		intern = _prop_array_internalize;
		break;

	case '"':
		ctx->poic_cp++;
		/* XXX Slightly gross. */
		if (*ctx->poic_cp == '"') {
			ctx->poic_cp++;
			ctx->poic_is_empty_element = true;
		}
		intern = _prop_string_internalize;
		break;

	case 't':
		if (ctx->poic_cp[1] == 'r' &&
		    ctx->poic_cp[2] == 'u' &&
		    ctx->poic_cp[3] == 'e') {
			/* XXX Slightly gross. */
			ctx->poic_tagname = ctx->poic_cp;
			ctx->poic_tagname_len = 4;
			ctx->poic_is_empty_element = true;
			intern = _prop_bool_internalize;
			ctx->poic_cp += 4;
		}
		break;

	case 'f':
		if (ctx->poic_cp[1] == 'a' &&
		    ctx->poic_cp[2] == 'l' &&
		    ctx->poic_cp[3] == 's' &&
		    ctx->poic_cp[4] == 'e') {
			/* XXX Slightly gross. */
			ctx->poic_tagname = ctx->poic_cp;
			ctx->poic_tagname_len = 5;
			ctx->poic_is_empty_element = true;
			intern = _prop_bool_internalize;
			ctx->poic_cp += 5;
		}
		break;

	default:
		if (ctx->poic_cp[0] == '+' ||
		    ctx->poic_cp[0] == '-' ||
		    (ctx->poic_cp[0] >= '0' && ctx->poic_cp[0] <= '9')) {
			intern = _prop_number_internalize;
		}
		break;
	}

	if (intern == NULL) {
		while (_prop_stack_pop(&stack, &obj, &iter, &data, NULL)) {
			iter_func = (prop_object_internalizer_continue_t)iter;
			(*iter_func)(&stack, &obj, ctx, data, NULL);
		}
		return NULL;
	}

	obj = NULL;
	if ((*intern)(&stack, &obj, ctx) == false) {
		goto match_start;
	}

	parent_obj = obj;
	while (_prop_stack_pop(&stack, &parent_obj, &iter, &data, NULL)) {
		iter_func = (prop_object_internalizer_continue_t)iter;
		if ((*iter_func)(&stack, &parent_obj, ctx, data,
							obj) == false) {
			goto match_start;
		}
		obj = parent_obj;
	}

	/* Ensure there's no trailing junk. */
	if (parent_obj != NULL) {
		ctx->poic_cp =
		    _prop_object_internalize_skip_whitespace(ctx->poic_cp);
		if (!_PROP_EOF(*ctx->poic_cp)) {
			prop_object_release(parent_obj);
			parent_obj = NULL;
		}
	}
	return parent_obj;
}

/*
 * _prop_object_internalize --
 *	Internalize a property list from a NUL-terminated data blob.
 */
prop_object_t
_prop_object_internalize(const char *data,
    const struct _prop_object_type_tags *initial_tag)
{
	struct _prop_object_internalize_context *ctx;
	prop_object_t obj;
	prop_format_t fmt;

	/*
	 * Skip all whitespace until and look at the first
	 * non-whitespace character to determine the format:
	 * An XML plist will always have '<' as the first non-ws
	 * character.  If we encounter something else, we assume
	 * it is JSON.
	 */
	data = _prop_object_internalize_skip_whitespace(data);
	if (_PROP_EOF(*data)) {
		return NULL;
	}

	fmt = *data == '<' ? PROP_FORMAT_XML : PROP_FORMAT_JSON;

	ctx = _prop_object_internalize_context_alloc(data, fmt);
	if (ctx == NULL) {
		return NULL;
	}

	if (fmt == PROP_FORMAT_XML) {
		obj = _prop_object_internalize_xml(ctx, initial_tag);
	} else {
		obj = _prop_object_internalize_json(ctx, initial_tag);
	}

 	_prop_object_internalize_context_free(ctx);
	return (obj);
}

_PROP_EXPORT prop_object_t
prop_object_internalize(const char *data)
{
	return _prop_object_internalize(data, NULL);
}

/*
 * _prop_object_internalize_context_alloc --
 *	Allocate an internalize context.
 */
struct _prop_object_internalize_context *
_prop_object_internalize_context_alloc(const char *data, prop_format_t fmt)
{
	struct _prop_object_internalize_context *ctx;

	ctx = _PROP_MALLOC(sizeof(*ctx), M_TEMP);
	if (ctx == NULL)
		return (NULL);

	ctx->poic_format = fmt;
	ctx->poic_data = ctx->poic_cp = data;

	/*
	 * If we're digesting JSON, check for a byte order mark and
	 * skip it, if present.  We should never see one, but we're
	 * allowed to detect and ignore it.  (RFC 8259 section 8.1)
	 */
	if (fmt == PROP_FORMAT_JSON) {
		if (((unsigned char)data[0] == 0xff &&
		     (unsigned char)data[1] == 0xfe) ||
		    ((unsigned char)data[0] == 0xfe &&
		     (unsigned char)data[1] == 0xff)) {
			ctx->poic_cp = data + 2;
		}

		/* No additional processing work to do for JSON. */
		return ctx;
	}

	/*
	 * Skip any whitespace and XML preamble stuff that we don't
	 * know about / care about.
	 */
	for (;;) {
		data = _prop_object_internalize_skip_whitespace(data);
		if (_PROP_EOF(*data) || *data != '<')
			goto bad;

#define	MATCH(str)	(strncmp(&data[1], str, strlen(str)) == 0)

		/*
		 * Skip over the XML preamble that Apple XML property
		 * lists usually include at the top of the file.
		 */
		if (MATCH("?xml ") ||
		    MATCH("!DOCTYPE plist")) {
			while (*data != '>' && !_PROP_EOF(*data))
				data++;
			if (_PROP_EOF(*data))
				goto bad;
			data++;	/* advance past the '>' */
			continue;
		}

		if (MATCH("<!--")) {
			ctx->poic_cp = data + 4;
			if (_prop_object_internalize_skip_comment(ctx) == false)
				goto bad;
			data = ctx->poic_cp;
			continue;
		}

#undef MATCH

		/*
		 * We don't think we should skip it, so let's hope we can
		 * parse it.
		 */
		break;
	}

	ctx->poic_cp = data;
	return (ctx);
 bad:
	_PROP_FREE(ctx, M_TEMP);
	return (NULL);
}

/*
 * _prop_object_internalize_context_free --
 *	Free an internalize context.
 */
void
_prop_object_internalize_context_free(
		struct _prop_object_internalize_context *ctx)
{

	_PROP_FREE(ctx, M_TEMP);
}

#if !defined(_KERNEL) && !defined(_STANDALONE)
/*
 * _prop_object_externalize_file_dirname --
 *	dirname(3), basically.  We have to roll our own because the
 *	system dirname(3) isn't reentrant.
 */
static void
_prop_object_externalize_file_dirname(const char *path, char *result)
{
	const char *lastp;
	size_t len;

	/*
	 * If `path' is a NULL pointer or points to an empty string,
	 * return ".".
	 */
	if (path == NULL || *path == '\0')
		goto singledot;

	/* String trailing slashes, if any. */
	lastp = path + strlen(path) - 1;
	while (lastp != path && *lastp == '/')
		lastp--;

	/* Terminate path at the last occurrence of '/'. */
	do {
		if (*lastp == '/') {
			/* Strip trailing slashes, if any. */
			while (lastp != path && *lastp == '/')
				lastp--;

			/* ...and copy the result into the result buffer. */
			len = (lastp - path) + 1 /* last char */;
			if (len > (PATH_MAX - 1))
				len = PATH_MAX - 1;

			memcpy(result, path, len);
			result[len] = '\0';
			return;
		}
	} while (--lastp >= path);

 	/* No /'s found, return ".". */
 singledot:
	strcpy(result, ".");
}

/*
 * _prop_object_externalize_write_file --
 *	Write an externalized dictionary to the specified file.
 *	The file is written atomically from the caller's perspective,
 *	and the mode set to 0666 modified by the caller's umask.
 */
static bool
_prop_object_externalize_write_file(const char *fname, const char *data,
    size_t len)
{
	char tname_store[PATH_MAX];
	char *tname = NULL;
	int fd = -1;
	int save_errno;
	mode_t myumask;
	bool rv = false;

	if (len > SSIZE_MAX) {
		errno = EFBIG;
		return false;
	}

	/*
	 * Get the directory name where the file is to be written
	 * and create the temporary file.
	 */
	_prop_object_externalize_file_dirname(fname, tname_store);
#define PLISTTMP "/.plistXXXXXX"
	if (strlen(tname_store) + strlen(PLISTTMP) >= sizeof(tname_store)) {
		errno = ENAMETOOLONG;
		return false;
	}
	strcat(tname_store, PLISTTMP);
#undef PLISTTMP

	if ((fd = mkstemp(tname_store)) == -1) {
		return (false);
	}
	tname = tname_store;

	if (write(fd, data, len) != (ssize_t)len) {
		goto bad;
	}

	if (fsync(fd) == -1) {
		goto bad;
	}

	myumask = umask(0);
	(void)umask(myumask);
	if (fchmod(fd, 0666 & ~myumask) == -1) {
		goto bad;
	}

	if (rename(tname, fname) == -1) {
		goto bad;
	}
	tname = NULL;

	rv = true;

 bad:
	save_errno = errno;
	if (fd != -1) {
		(void) close(fd);
	}
	if (tname != NULL) {
		(void) unlink(tname);
	}
	errno = save_errno;
	return rv;
}

/*
 * _prop_object_externalize_to_file --
 *	Externalize an object to the specified file.
 */
bool
_prop_object_externalize_to_file(struct _prop_object *obj, const char *fname,
    prop_format_t fmt)
{
	char *data = _prop_object_externalize(obj, fmt);
	if (data == NULL) {
		return false;
	}
	bool rv = _prop_object_externalize_write_file(fname, data,
	    strlen(data));
	int save_errno = errno;
	_PROP_FREE(data, M_TEMP);
	errno = save_errno;

	return rv;
}

struct _prop_object_internalize_mapped_file {
	char *	poimf_xml;
	size_t	poimf_mapsize;
};

/*
 * _prop_object_internalize_map_file --
 *	Map a file for the purpose of internalizing it.
 */
static struct _prop_object_internalize_mapped_file *
_prop_object_internalize_map_file(const char *fname)
{
	struct stat sb;
	struct _prop_object_internalize_mapped_file *mf;
	size_t pgsize = (size_t)sysconf(_SC_PAGESIZE);
	size_t pgmask = pgsize - 1;
	bool need_guard = false;
	int fd;

	mf = _PROP_MALLOC(sizeof(*mf), M_TEMP);
	if (mf == NULL)
		return (NULL);

	fd = open(fname, O_RDONLY, 0400);
	if (fd == -1) {
		_PROP_FREE(mf, M_TEMP);
		return (NULL);
	}

	if (fstat(fd, &sb) == -1) {
		(void) close(fd);
		_PROP_FREE(mf, M_TEMP);
		return (NULL);
	}
	mf->poimf_mapsize = ((size_t)sb.st_size + pgmask) & ~pgmask;
	if (mf->poimf_mapsize < (size_t)sb.st_size) {
		(void) close(fd);
		_PROP_FREE(mf, M_TEMP);
		return (NULL);
	}

	/*
	 * If the file length is an integral number of pages, then we
	 * need to map a guard page at the end in order to provide the
	 * necessary NUL-termination of the buffer.
	 */
	if ((sb.st_size & pgmask) == 0)
		need_guard = true;

	mf->poimf_xml = mmap(NULL, need_guard ? mf->poimf_mapsize + pgsize
			    		      : mf->poimf_mapsize,
			    PROT_READ, MAP_FILE|MAP_SHARED, fd, (off_t)0);
	(void) close(fd);
	if (mf->poimf_xml == MAP_FAILED) {
		_PROP_FREE(mf, M_TEMP);
		return (NULL);
	}
#ifdef POSIX_MADV_SEQUENTIAL
	(void) posix_madvise(mf->poimf_xml, mf->poimf_mapsize,
	    POSIX_MADV_SEQUENTIAL);
#endif

	if (need_guard) {
		if (mmap(mf->poimf_xml + mf->poimf_mapsize,
			 pgsize, PROT_READ,
			 MAP_ANON|MAP_PRIVATE|MAP_FIXED, -1,
			 (off_t)0) == MAP_FAILED) {
			(void) munmap(mf->poimf_xml, mf->poimf_mapsize);
			_PROP_FREE(mf, M_TEMP);
			return (NULL);
		}
		mf->poimf_mapsize += pgsize;
	}

	return (mf);
}

/*
 * _prop_object_internalize_unmap_file --
 *	Unmap a file previously mapped for internalizing.
 */
static void
_prop_object_internalize_unmap_file(
    struct _prop_object_internalize_mapped_file *mf)
{

#ifdef POSIX_MADV_DONTNEED
	(void) posix_madvise(mf->poimf_xml, mf->poimf_mapsize,
	    POSIX_MADV_DONTNEED);
#endif
	(void) munmap(mf->poimf_xml, mf->poimf_mapsize);
	_PROP_FREE(mf, M_TEMP);
}

/*
 * _prop_object_internalize_from_file --
 *	Internalize a property list from a file.
 */
prop_object_t
_prop_object_internalize_from_file(const char *fname,
    const struct _prop_object_type_tags *initial_tag)
{
	struct _prop_object_internalize_mapped_file *mf;
	prop_object_t obj;

	mf = _prop_object_internalize_map_file(fname);
	if (mf == NULL) {
		return NULL;
	}
	obj = _prop_object_internalize(mf->poimf_xml, initial_tag);
	_prop_object_internalize_unmap_file(mf);

	return obj;
}

_PROP_EXPORT prop_object_t
prop_object_internalize_from_file(const char *fname)
{
	return _prop_object_internalize_from_file(fname, NULL);
}
#endif /* !_KERNEL && !_STANDALONE */

static prop_format_t	_prop_format_default = PROP_FORMAT_XML;

/*
 * prop_object_externalize --
 *	Externalize an object in the default format.
 */
_PROP_EXPORT char *
prop_object_externalize(prop_object_t po)
{
	return _prop_object_externalize((struct _prop_object *)po,
	    _prop_format_default);
}

/*
 * prop_object_externalize_with_format --
 *	Externalize an object in the specified format.
 */
_PROP_EXPORT char *
prop_object_externalize_with_format(prop_object_t po, prop_format_t fmt)
{
	return _prop_object_externalize((struct _prop_object *)po, fmt);
}

#if !defined(_KERNEL) && !defined(_STANDALONE)
/*
 * prop_object_externalize_to_file --
 *	Externalize an object to the specifed file in the default format.
 */
_PROP_EXPORT bool
prop_object_externalize_to_file(prop_object_t po, const char *fname)
{
	return _prop_object_externalize_to_file((struct _prop_object *)po,
	    fname, _prop_format_default);
}

/*
 * prop_object_externalize_to_file_with_format --
 *	Externalize an object to the specifed file in the specified format.
 */
_PROP_EXPORT bool
prop_object_externalize_to_file_with_format(prop_object_t po,
    const char *fname, prop_format_t fmt)
{
	return _prop_object_externalize_to_file((struct _prop_object *)po,
	    fname, fmt);
}
#endif /* !_KERNEL && !_STANDALONE */

/*
 * prop_object_retain --
 *	Increment the reference count on an object.
 */
_PROP_EXPORT void
prop_object_retain(prop_object_t obj)
{
	struct _prop_object *po = obj;
	uint32_t ncnt __unused;

	_PROP_ATOMIC_INC32_NV(&po->po_refcnt, ncnt);
	_PROP_ASSERT(ncnt != 0);
}

/*
 * prop_object_release_emergency
 *	A direct free with prop_object_release failed.
 *	Walk down the tree until a leaf is found and
 *	free that. Do not recurse to avoid stack overflows.
 *
 *	This is a slow edge condition, but necessary to
 *	guarantee that an object can always be freed.
 */
static void
prop_object_release_emergency(prop_object_t obj)
{
	struct _prop_object *po;
	void (*unlock)(void);
	prop_object_t parent = NULL;
	uint32_t ocnt;

	for (;;) {
		po = obj;
		_PROP_ASSERT(obj);

		if (po->po_type->pot_lock != NULL)
		po->po_type->pot_lock();

		/* Save pointerto unlock function */
		unlock = po->po_type->pot_unlock;

		/* Dance a bit to make sure we always get the non-racy ocnt */
		_PROP_ATOMIC_DEC32_NV(&po->po_refcnt, ocnt);
		ocnt++;
		_PROP_ASSERT(ocnt != 0);

		if (ocnt != 1) {
			if (unlock != NULL)
				unlock();
			break;
		}

		_PROP_ASSERT(po->po_type);
		if ((po->po_type->pot_free)(NULL, &obj) ==
		    _PROP_OBJECT_FREE_DONE) {
			if (unlock != NULL)
				unlock();
			break;
		}

		if (unlock != NULL)
			unlock();

		parent = po;
		_PROP_ATOMIC_INC32(&po->po_refcnt);
	}
	_PROP_ASSERT(parent);
	/* One object was just freed. */
	po = parent;
	(*po->po_type->pot_emergency_free)(parent);
}

/*
 * prop_object_release --
 *	Decrement the reference count on an object.
 *
 *	Free the object if we are releasing the final
 *	reference.
 */
_PROP_EXPORT void
prop_object_release(prop_object_t obj)
{
	struct _prop_object *po;
	struct _prop_stack stack;
	void (*unlock)(void);
	int ret;
	uint32_t ocnt;

	_prop_stack_init(&stack);

	do {
		do {
			po = obj;
			_PROP_ASSERT(obj);

			if (po->po_type->pot_lock != NULL)
				po->po_type->pot_lock();

			/* Save pointer to object unlock function */
			unlock = po->po_type->pot_unlock;

			_PROP_ATOMIC_DEC32_NV(&po->po_refcnt, ocnt);
			ocnt++;
			_PROP_ASSERT(ocnt != 0);

			if (ocnt != 1) {
				ret = 0;
				if (unlock != NULL)
					unlock();
				break;
			}

			ret = (po->po_type->pot_free)(&stack, &obj);

			if (unlock != NULL)
				unlock();

			if (ret == _PROP_OBJECT_FREE_DONE)
				break;

			_PROP_ATOMIC_INC32(&po->po_refcnt);
		} while (ret == _PROP_OBJECT_FREE_RECURSE);
		if (ret == _PROP_OBJECT_FREE_FAILED)
			prop_object_release_emergency(obj);
	} while (_prop_stack_pop(&stack, &obj, NULL, NULL, NULL));
}

/*
 * prop_object_type --
 *	Return the type of an object.
 */
_PROP_EXPORT prop_type_t
prop_object_type(prop_object_t obj)
{
	struct _prop_object *po = obj;

	if (obj == NULL)
		return (PROP_TYPE_UNKNOWN);

	return (po->po_type->pot_type);
}

/*
 * prop_object_equals --
 *	Returns true if thw two objects are equivalent.
 */
_PROP_EXPORT bool
prop_object_equals(prop_object_t obj1, prop_object_t obj2)
{
	return (prop_object_equals_with_error(obj1, obj2, NULL));
}

_PROP_EXPORT bool
prop_object_equals_with_error(prop_object_t obj1, prop_object_t obj2,
    bool *error_flag)
{
	struct _prop_object *po1;
	struct _prop_object *po2;
	void *stored_pointer1, *stored_pointer2;
	prop_object_t next_obj1, next_obj2;
	struct _prop_stack stack;
	_prop_object_equals_rv_t ret;

	_prop_stack_init(&stack);
	if (error_flag)
		*error_flag = false;

 start_subtree:
	stored_pointer1 = NULL;
	stored_pointer2 = NULL;
	po1 = obj1;
	po2 = obj2;

	if (po1->po_type != po2->po_type)
		return (false);

 continue_subtree:
	ret = (*po1->po_type->pot_equals)(obj1, obj2,
					  &stored_pointer1, &stored_pointer2,
					  &next_obj1, &next_obj2);
	if (ret == _PROP_OBJECT_EQUALS_FALSE)
		goto finish;
	if (ret == _PROP_OBJECT_EQUALS_TRUE) {
		if (!_prop_stack_pop(&stack, &obj1, &obj2,
				     &stored_pointer1, &stored_pointer2))
			return true;
		po1 = obj1;
		po2 = obj2;
		goto continue_subtree;
	}
	_PROP_ASSERT(ret == _PROP_OBJECT_EQUALS_RECURSE);

	if (!_prop_stack_push(&stack, obj1, obj2,
			      stored_pointer1, stored_pointer2)) {
		if (error_flag)
			*error_flag = true;
		goto finish;
	}
	obj1 = next_obj1;
	obj2 = next_obj2;
	goto start_subtree;

finish:
	while (_prop_stack_pop(&stack, &obj1, &obj2, NULL, NULL)) {
		po1 = obj1;
		(*po1->po_type->pot_equals_finish)(obj1, obj2);
	}
	return (false);
}

/*
 * prop_object_iterator_next --
 *	Return the next item during an iteration.
 */
_PROP_EXPORT prop_object_t
prop_object_iterator_next(prop_object_iterator_t pi)
{

	return ((*pi->pi_next_object)(pi));
}

/*
 * prop_object_iterator_reset --
 *	Reset the iterator to the first object so as to restart
 *	iteration.
 */
_PROP_EXPORT void
prop_object_iterator_reset(prop_object_iterator_t pi)
{

	(*pi->pi_reset)(pi);
}

/*
 * prop_object_iterator_release --
 *	Release the object iterator.
 */
_PROP_EXPORT void
prop_object_iterator_release(prop_object_iterator_t pi)
{

	prop_object_release(pi->pi_obj);
	_PROP_FREE(pi, M_TEMP);
}