/*
 * fragment.c
 * Management of fragment lists.
 *
 * SPDX-License-Identifier: pkgconf
 *
 * Copyright (c) 2012, 2013, 2014 pkgconf authors (see AUTHORS).
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * This software is provided 'as is' and without any warranty, express or
 * implied.  In no event shall the authors be liable for any damages arising
 * from the use of this software.
 */

#include <libpkgconf/config.h>
#include <libpkgconf/stdinc.h>
#include <libpkgconf/libpkgconf.h>

#ifndef _WIN32
#include <locale.h>
#include <langinfo.h>
#endif

#ifdef __APPLE__
#include <xlocale.h>
#endif

/*
 * !doc
 *
 * libpkgconf `fragment` module
 * ============================
 *
 * The `fragment` module provides low-level management and rendering of fragment lists.  A
 * `fragment list` contains various `fragments` of text (such as ``-I /usr/include``) in a matter
 * which is composable, mergeable and reorderable.
 */

struct pkgconf_fragment_check {
	const char *token;
	size_t len;
};

static inline bool
pkgconf_fragment_is_greedy(const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-F", 2},
		{"-I", 2},
		{"-L", 2},
		{"-D", 2},
		{"-l", 2},
	};

	if (*string != '-')
		return false;

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
		{
			/* if it is the bare flag, then we want the next token to be the data */
			if (!*(string + check_fragments[i].len))
				return true;
		}

	return false;
}

static inline bool
pkgconf_fragment_should_check_sysroot(const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-F", 2},
		{"-I", 2},
		{"-L", 2},
		{"-isystem", 8},
		{"-idirafter", 10},
	};

	if (*string != '-')
		return false;

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
			return true;

	return false;
}

static inline bool
pkgconf_fragment_is_unmergeable(const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-framework", 10},
		{"-isystem", 8},
		{"-idirafter", 10},
		{"-pthread", 8},
		{"-Wa,", 4},
		{"-Wl,", 4},
		{"-Wp,", 4},
		{"-trigraphs", 10},
		{"-pedantic", 9},
		{"-ansi", 5},
		{"-std=", 5},
		{"-stdlib=", 8},
		{"-include", 8},
		{"-nostdinc", 9},
		{"-nostdlibinc", 12},
		{"-nobuiltininc", 13},
		{"-nodefaultlibs", 14},
	};

	if (*string != '-')
		return true;

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
			return true;

	/* only one pair of {-flag, arg} may be merged together */
	if (strchr(string, ' ') != NULL)
		return false;

	return false;
}

static inline bool
pkgconf_fragment_only_group_one(const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-framework", 10},
		{"-isystem", 8},
		{"-idirafter", 10},
		{"-include", 8},
	};

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
			return true;

	return false;
}

static inline bool
pkgconf_fragment_is_groupable(const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-Wl,--start-group", 17},
	};

	if (pkgconf_fragment_only_group_one(string))
		return true;

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
			return true;

	return false;
}

static inline bool
pkgconf_fragment_is_terminus(const char *parent, const char *string)
{
	static const struct pkgconf_fragment_check check_fragments[] = {
		{"-Wl,--end-group", 15},
	};

	if (pkgconf_fragment_only_group_one(parent))
		return true;

	for (size_t i = 0; i < PKGCONF_ARRAY_SIZE(check_fragments); i++)
		if (!strncmp(string, check_fragments[i].token, check_fragments[i].len))
			return true;

	return false;
}

static inline bool
pkgconf_fragment_is_special(const char *string)
{
	if (*string != '-')
		return true;

	if (!strncmp(string, "-lib:", 5))
		return true;

	return pkgconf_fragment_is_unmergeable(string);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_insert(const pkgconf_client_t *client, pkgconf_list_t *list, char type, const char *data, bool tail)
 *
 *    Adds a `fragment` of text to a `fragment list` directly without interpreting it.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* list: The fragment list.
 *    :param char type: The type of the fragment.
 *    :param char* data: The data of the fragment.
 *    :param bool tail: Whether to place the fragment at the beginning of the list or the end.
 *    :return: nothing
 */
void
pkgconf_fragment_insert(pkgconf_client_t *client, pkgconf_list_t *list, char type, const char *data, bool tail)
{
	(void) client;

	pkgconf_fragment_t *frag;

	frag = calloc(1, sizeof(pkgconf_fragment_t));
	if (frag == NULL)
		return;

	frag->type = type;
	frag->data = strdup(data);

	if (tail)
	{
		pkgconf_node_insert_tail(&frag->iter, frag, list);
		return;
	}

	pkgconf_node_insert(&frag->iter, frag, list);
}

static bool
should_inject_sysroot(const pkgconf_client_t *client, const char *string, bool saw_sysroot, unsigned int flags)
{
	/* emulating original pkg-config: we never inject sysroot */
	if (client->flags & PKGCONF_PKG_PKGF_FDO_SYSROOT_RULES)
		return false;

	/* we never automatically inject sysroot on -uninstalled packages */
	if (flags & PKGCONF_PKG_PROPF_UNINSTALLED)
	{
		/* ... unless we are emulating pkgconf 1.x */
		if (!(client->flags & PKGCONF_PKG_PKGF_PKGCONF1_SYSROOT_RULES))
			return false;
	}

	if (client->sysroot_dir == NULL)
		return false;

	if (saw_sysroot)
		return false;

	if (!pkgconf_fragment_should_check_sysroot(string))
		return false;

	if (!strncmp(string + 2, client->sysroot_dir, strlen(client->sysroot_dir)) &&
		*(string + 2 + strlen(client->sysroot_dir)) == '/')
	{
		return false;
	}

	return true;
}

static bool
should_inject_sysroot_child(const pkgconf_client_t *client, const pkgconf_fragment_t *last, const char *string, bool saw_sysroot, unsigned int flags)
{
	/* emulating original pkg-config: we never inject sysroot */
	if (client->flags & PKGCONF_PKG_PKGF_FDO_SYSROOT_RULES)
		return false;

	/* we never automatically inject sysroot on -uninstalled packages */
	if (flags & PKGCONF_PKG_PROPF_UNINSTALLED)
	{
		/* ... unless we are emulating pkgconf 1.x */
		if (!(client->flags & PKGCONF_PKG_PKGF_PKGCONF1_SYSROOT_RULES))
			return false;
	}

	if (last->type)
		return false;

	if (last->data == NULL)
		return false;

	if (client->sysroot_dir == NULL)
		return false;

	if (saw_sysroot)
		return false;

	if (!pkgconf_fragment_should_check_sysroot(last->data))
		return false;

	if (!strncmp(string, client->sysroot_dir, strlen(client->sysroot_dir)) &&
		*(string + strlen(client->sysroot_dir)) == '/')
	{
		return false;
	}

	return true;
}

static inline bool
fragment_is_unquoted_var(const char *value)
{
	size_t len;

	if (value == NULL)
		return false;

	len = strlen(value);

	if (len < 4 || value[0] != '$')
		return false;

	if (value[1] == '{' && value[len - 1] == '}')
		return true;

	return false;
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_add(const pkgconf_client_t *client, pkgconf_list_t *list, const char *string, unsigned int flags)
 *
 *    Adds a `fragment` of text to a `fragment list`, possibly modifying the fragment if a sysroot is set.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* list: The fragment list.
 *    :param char* string: The string of text to add as a fragment to the fragment list.
 *    :param uint flags: Parsing-related flags for the package.
 *    :return: nothing
 */
void
pkgconf_fragment_add(pkgconf_client_t *client, pkgconf_list_t *list, pkgconf_list_t *vars, const char *value, unsigned int flags)
{
	pkgconf_list_t *target = list;
	pkgconf_fragment_t *frag;
	pkgconf_buffer_t evalbuf = PKGCONF_BUFFER_INITIALIZER;
	bool saw_sysroot = false;
	char *string;

	if (!pkgconf_bytecode_eval_str_to_buf(client, vars, value, &saw_sysroot, &evalbuf))
	{
		pkgconf_buffer_finalize(&evalbuf);
		return;
	}

	string = pkgconf_buffer_freeze(&evalbuf);
	if (string == NULL)
		return;

	if (fragment_is_unquoted_var(value))
	{
		pkgconf_fragment_parse(client, list, vars, string, flags);
		free(string);
		return;
	}

	if (list->tail != NULL && list->tail->data != NULL &&
		!(client->flags & PKGCONF_PKG_PKGF_DONT_MERGE_SPECIAL_FRAGMENTS))
	{
		pkgconf_fragment_t *parent = list->tail->data;

		/* only attempt to merge 'special' fragments together */
		if (!parent->type && parent->data != NULL &&
			pkgconf_fragment_is_unmergeable(parent->data) &&
			!(parent->flags & PKGCONF_PKG_FRAGF_TERMINATED))
		{
			if (pkgconf_fragment_is_groupable(parent->data))
				target = &parent->children;

			if (pkgconf_fragment_is_terminus(parent->data, string))
				parent->flags |= PKGCONF_PKG_FRAGF_TERMINATED;

			PKGCONF_TRACE(client, "adding fragment as child to list @%p", target);
		}
	}

	frag = calloc(1, sizeof(pkgconf_fragment_t));
	if (frag == NULL)
	{
		PKGCONF_TRACE(client, "failed to add new fragment due to allocation failure to list @%p", target);
		free(string);
		return;
	}

	if (strlen(string) > 1 && !pkgconf_fragment_is_special(string))
	{
		frag->type = *(string + 1);

		if (should_inject_sysroot(client, string, saw_sysroot, flags))
		{
			pkgconf_buffer_t sysroot_buf = PKGCONF_BUFFER_INITIALIZER;

			pkgconf_buffer_append(&sysroot_buf, client->sysroot_dir);
			pkgconf_buffer_append(&sysroot_buf, string + 2);

			frag->data = pkgconf_buffer_freeze(&sysroot_buf);
		}
		else
			frag->data = strdup(string + 2);

		PKGCONF_TRACE(client, "added fragment {%c, '%s'} to list @%p", frag->type, frag->data, list);
	}
	else
	{
		if (client->sysroot_dir != NULL && list->tail != NULL && list->tail->data != NULL)
		{
			pkgconf_fragment_t *last = list->tail->data;

			if (should_inject_sysroot_child(client, last, string, saw_sysroot, flags))
			{
				pkgconf_buffer_t sysroot_buf = PKGCONF_BUFFER_INITIALIZER;

				pkgconf_buffer_append(&sysroot_buf, client->sysroot_dir);
				pkgconf_buffer_append(&sysroot_buf, string);

				free(string);
				string = pkgconf_buffer_freeze(&sysroot_buf);
			}
		}

		frag->type = 0;
		frag->data = strdup(string);

		PKGCONF_TRACE(client, "created special fragment {'%s'} in list @%p", frag->data, target);
	}

	pkgconf_node_insert_tail(&frag->iter, frag, target);
	free(string);
}

static inline pkgconf_fragment_t *
pkgconf_fragment_lookup(pkgconf_list_t *list, const pkgconf_fragment_t *base)
{
	pkgconf_node_t *node;

	PKGCONF_FOREACH_LIST_ENTRY_REVERSE(list->tail, node)
	{
		pkgconf_fragment_t *frag = node->data;

		if (base->type != frag->type)
			continue;

		if (base->data == NULL || frag->data == NULL)
		{
			if (base->data == frag->data)
				return frag;

			continue;
		}

		if (!strcmp(base->data, frag->data))
			return frag;
	}

	return NULL;
}

static inline bool
pkgconf_fragment_can_merge_back(const pkgconf_fragment_t *base, unsigned int flags, bool is_private)
{
	(void) flags;

	if (base->type == 'l')
	{
		if (is_private)
			return false;

		return true;
	}

	if (base->type == 'F')
		return false;
	if (base->type == 'L')
		return false;
	if (base->type == 'I')
		return false;

	return true;
}

static inline bool
pkgconf_fragment_can_merge(const pkgconf_fragment_t *base, unsigned int flags, bool is_private)
{
	(void) flags;

	if (is_private)
		return false;

	if (base->children.head != NULL)
		return false;

	if (base->data == NULL)
		return false;

	return pkgconf_fragment_is_unmergeable(base->data);
}

static inline pkgconf_fragment_t *
pkgconf_fragment_exists(pkgconf_list_t *list, const pkgconf_fragment_t *base, unsigned int flags, bool is_private)
{
	if (!pkgconf_fragment_can_merge_back(base, flags, is_private))
		return NULL;

	if (!pkgconf_fragment_can_merge(base, flags, is_private))
		return NULL;

	return pkgconf_fragment_lookup(list, base);
}

static inline bool
pkgconf_fragment_should_merge(const pkgconf_fragment_t *base)
{
	const pkgconf_fragment_t *parent;

	/* if we are the first fragment, that means the next fragment is the same, so it's always safe. */
	if (base->iter.prev == NULL)
		return true;

	/* this really shouldn't ever happen, but handle it */
	parent = base->iter.prev->data;
	if (parent == NULL)
		return true;

	switch (parent->type)
	{
	case 'l':
	case 'L':
	case 'I':
		return true;
	default:
		return !base->type || parent->type == base->type;
	}
}

/*
 * !doc
 *
 * .. c:function:: bool pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
 *
 *    Checks if a `fragment` contains a `system path`.  System paths are detected at compile time and optionally overridden by
 *    the ``PKG_CONFIG_SYSTEM_INCLUDE_PATH`` and ``PKG_CONFIG_SYSTEM_LIBRARY_PATH`` environment variables.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object the fragment belongs to.
 *    :param pkgconf_fragment_t* frag: The fragment being checked.
 *    :return: true if the fragment contains a system path, else false
 *    :rtype: bool
 */
bool
pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
{
	const pkgconf_list_t *check_paths = NULL;

	switch (frag->type)
	{
	case 'L':
		check_paths = &client->filter_libdirs;
		break;
	case 'I':
		check_paths = &client->filter_includedirs;
		break;
	default:
		return false;
	}

	return pkgconf_path_match_list(frag->data, check_paths);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_copy(const pkgconf_client_t *client, pkgconf_list_t *list, const pkgconf_fragment_t *base, bool is_private)
 *
 *    Copies a `fragment` to another `fragment list`, possibly removing a previous copy of the `fragment`
 *    in a process known as `mergeback`.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* list: The list the fragment is being added to.
 *    :param pkgconf_fragment_t* base: The fragment being copied.
 *    :param bool is_private: Whether the fragment list is a `private` fragment list (static linking).
 *    :return: nothing
 */
void
pkgconf_fragment_copy(const pkgconf_client_t *client, pkgconf_list_t *list, const pkgconf_fragment_t *base, bool is_private)
{
	pkgconf_fragment_t *frag;

	if ((frag = pkgconf_fragment_exists(list, base, client->flags, is_private)) != NULL)
	{
		if (pkgconf_fragment_should_merge(frag))
			pkgconf_fragment_delete(list, frag);
	}
	else if (!is_private && !pkgconf_fragment_can_merge_back(base, client->flags, is_private) && (pkgconf_fragment_lookup(list, base) != NULL))
		return;

	frag = calloc(1, sizeof(pkgconf_fragment_t));
	if (frag == NULL)
		return;

	frag->type = base->type;
	pkgconf_fragment_copy_list(client, &frag->children, &base->children);
	if (base->data != NULL)
		frag->data = strdup(base->data);

	pkgconf_node_insert_tail(&frag->iter, frag, list);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_copy_list(const pkgconf_client_t *client, pkgconf_list_t *list, const pkgconf_list_t *base)
 *
 *    Copies a `fragment list` to another `fragment list`, possibly removing a previous copy of the fragments
 *    in a process known as `mergeback`.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* list: The list the fragments are being added to.
 *    :param pkgconf_list_t* base: The list the fragments are being copied from.
 *    :return: nothing
 */
void
pkgconf_fragment_copy_list(const pkgconf_client_t *client, pkgconf_list_t *list, const pkgconf_list_t *base)
{
	pkgconf_node_t *node;

	PKGCONF_FOREACH_LIST_ENTRY(base->head, node)
	{
		pkgconf_fragment_t *frag = node->data;

		pkgconf_fragment_copy(client, list, frag, true);
	}
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_filter(const pkgconf_client_t *client, pkgconf_list_t *dest, pkgconf_list_t *src, pkgconf_fragment_filter_func_t filter_func)
 *
 *    Copies a `fragment list` to another `fragment list` which match a user-specified filtering function.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* dest: The destination list.
 *    :param pkgconf_list_t* src: The source list.
 *    :param pkgconf_fragment_filter_func_t filter_func: The filter function to use.
 *    :param void* data: Optional data to pass to the filter function.
 *    :return: nothing
 */
void
pkgconf_fragment_filter(const pkgconf_client_t *client, pkgconf_list_t *dest, pkgconf_list_t *src, pkgconf_fragment_filter_func_t filter_func, void *data)
{
	pkgconf_node_t *node;

	PKGCONF_FOREACH_LIST_ENTRY(src->head, node)
	{
		pkgconf_fragment_t *frag = node->data;

		if (filter_func(client, frag, data))
			pkgconf_fragment_copy(client, dest, frag, true);
	}
}

/*
 * !doc
 *
 * .. c:function:: bool pkgconf_is_locale_utf8(void)
 *
 *    Check whether text is expected to be UTF-8 encoded in the current environment.
 *
 *    :return: :code:`true` if text is expected to be UTF-8 encoded, :code:`false` otherwise.
 */
#ifndef _WIN32
static bool
codeset_is_utf8(const char *codeset)
{
	return codeset != NULL && (!strcasecmp(codeset, "UTF-8") || !strcasecmp(codeset, "UTF8"));
}
#endif

bool
pkgconf_is_locale_utf8(void)
{
#ifdef _WIN32
	return GetACP() == CP_UTF8;
#else
	static int cached = -1;

	if (cached >= 0)
		return cached;

#if HAVE_DECL_NL_LANGINFO_L
	locale_t loc = newlocale(LC_CTYPE_MASK, "", (locale_t)0);

	if (loc != (locale_t)0)
	{
		cached = codeset_is_utf8(nl_langinfo_l(CODESET, loc));
		freelocale(loc);
	}
	else
		cached = 0;
#else
	const char *prev_locale = setlocale(LC_CTYPE, NULL);
	char *saved_locale = prev_locale != NULL ? strdup(prev_locale) : NULL;

	setlocale(LC_CTYPE, "");
	cached = codeset_is_utf8(nl_langinfo(CODESET));
	setlocale(LC_CTYPE, saved_locale != NULL ? saved_locale : "C");
	free(saved_locale);
#endif

	return cached;
#endif
}

static void
fragment_quote(pkgconf_buffer_t *out, const pkgconf_fragment_t *frag)
{
	if (frag->data == NULL)
		return;

	const pkgconf_buffer_t *src = PKGCONF_BUFFER_FROM_STR(frag->data);
	const pkgconf_span_t quote_spans[] = {
		{ 0x00, 0x1f },
		{ (unsigned char)' ', (unsigned char)'#' },
		{ (unsigned char)'%', (unsigned char)'\'' },
		{ (unsigned char)'*', (unsigned char)'*' },
		{ (unsigned char)';', (unsigned char)'<' },
		{ (unsigned char)'>', (unsigned char)'?' },
		{ (unsigned char)'[', (unsigned char)']' },
		{ (unsigned char)'`', (unsigned char)'`' },
		{ (unsigned char)'{', (unsigned char)'}' },
		{ 0x7f, 0xff },
	};

	/* If the local is UTF-8 we must not split character over 0x7f because it would add "\" between each bytes.
	   So only DEL (0x7f) needs escaping */
	const pkgconf_span_t quote_spans_utf8[] = {
		{ 0x00, 0x1f },
		{ (unsigned char)' ', (unsigned char)'#' },
		{ (unsigned char)'%', (unsigned char)'\'' },
		{ (unsigned char)'*', (unsigned char)'*' },
		{ (unsigned char)';', (unsigned char)'<' },
		{ (unsigned char)'>', (unsigned char)'?' },
		{ (unsigned char)'[', (unsigned char)']' },
		{ (unsigned char)'`', (unsigned char)'`' },
		{ (unsigned char)'{', (unsigned char)'}' },
		{ 0x7f, 0x7f },
	};

	if (pkgconf_is_locale_utf8())
		pkgconf_buffer_escape(out, src, quote_spans_utf8, PKGCONF_ARRAY_SIZE(quote_spans_utf8));
	else
		pkgconf_buffer_escape(out, src, quote_spans, PKGCONF_ARRAY_SIZE(quote_spans));
}

static void
fragment_render(const pkgconf_fragment_render_ctx_t *ctx, const pkgconf_fragment_t *frag, pkgconf_buffer_t *buf)
{
	const pkgconf_node_t *iter;
	pkgconf_buffer_t quoted = PKGCONF_BUFFER_INITIALIZER;

	fragment_quote(&quoted, frag);

	if (frag->type)
		pkgconf_buffer_append_fmt(buf, "-%c", frag->type);

	pkgconf_buffer_append(buf, pkgconf_buffer_str_or_empty(&quoted));
	pkgconf_buffer_finalize(&quoted);

	PKGCONF_FOREACH_LIST_ENTRY(frag->children.head, iter)
	{
		const pkgconf_fragment_t *child_frag = iter->data;

		pkgconf_buffer_push_byte(buf, ctx->delim);
		fragment_render(ctx, child_frag, buf);
	}
}

static const pkgconf_fragment_render_ops_t default_render_ops = {
	.render = fragment_render
};

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_render_buf(const pkgconf_list_t *list, char *buf, size_t buflen, bool escape, const pkgconf_fragment_render_ops_t *ops, char delim)
 *
 *    Renders a `fragment list` into a buffer.
 *
 *    :param pkgconf_list_t* list: The `fragment list` being rendered.
 *    :param pkgconf_buffer_t* buf: The buffer to render the fragment list into.
 *    :param bool escape: Whether or not to escape special shell characters (deprecated).
 *    :param pkgconf_fragment_render_ops_t* ops: An optional ops structure to use for custom renderers, else ``NULL``.
 *    :param char delim: The delimiter to use between fragments.
 *    :return: nothing
 */
void
pkgconf_fragment_render_buf(const pkgconf_list_t *list, pkgconf_buffer_t *buf, bool escape, const pkgconf_fragment_render_ops_t *ops, char delim)
{
	pkgconf_node_t *node;
	pkgconf_fragment_render_ctx_t ctx = {
		.escape = escape,
		.delim = delim,
	};

	ops = ops != NULL ? ops : &default_render_ops;

	PKGCONF_FOREACH_LIST_ENTRY(list->head, node)
	{
		const pkgconf_fragment_t *frag = node->data;
		ops->render(&ctx, frag, buf);

		if (node->next != NULL)
			pkgconf_buffer_push_byte(buf, ctx.delim);
	}
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_delete(pkgconf_list_t *list, pkgconf_fragment_t *node)
 *
 *    Delete a `fragment node` from a `fragment list`.
 *
 *    :param pkgconf_list_t* list: The `fragment list` to delete from.
 *    :param pkgconf_fragment_t* node: The `fragment node` to delete.
 *    :return: nothing
 */
void
pkgconf_fragment_delete(pkgconf_list_t *list, pkgconf_fragment_t *node)
{
	pkgconf_node_delete(&node->iter, list);

	free(node->data);
	free(node);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_fragment_free(pkgconf_list_t *list)
 *
 *    Delete an entire `fragment list`.
 *
 *    :param pkgconf_list_t* list: The `fragment list` to delete.
 *    :return: nothing
 */
void
pkgconf_fragment_free(pkgconf_list_t *list)
{
	pkgconf_node_t *node, *next;

	PKGCONF_FOREACH_LIST_ENTRY_SAFE(list->head, next, node)
	{
		pkgconf_fragment_t *frag = node->data;

		pkgconf_fragment_free(&frag->children);
		free(frag->data);
		free(frag);
	}
}

/*
 * !doc
 *
 * .. c:function:: bool pkgconf_fragment_parse(const pkgconf_client_t *client, pkgconf_list_t *list, pkgconf_list_t *vars, const char *value)
 *
 *    Parse a string into a `fragment list`.
 *
 *    :param pkgconf_client_t* client: The pkgconf client being accessed.
 *    :param pkgconf_list_t* list: The `fragment list` to add the fragment entries to.
 *    :param pkgconf_list_t* vars: A list of variables to use for variable substitution.
 *    :param uint flags: Any parsing flags to be aware of.
 *    :param char* value: The string to parse into fragments.
 *    :return: true on success, false on parse error
 */
bool
pkgconf_fragment_parse(pkgconf_client_t *client, pkgconf_list_t *list, pkgconf_list_t *vars, const char *value, unsigned int flags)
{
	int i, ret, argc;
	char **argv;

	ret = pkgconf_argv_split(value, &argc, &argv);
	if (ret < 0)
	{
		PKGCONF_TRACE(client, "unable to parse fragment string [%s]", value);
		return false;
	}

	for (i = 0; i < argc; i++)
	{
		if (argv[i] == NULL)
		{
			PKGCONF_TRACE(client, "parsed fragment string is inconsistent: argc = %d while argv[%d] == NULL", argc, i);
			pkgconf_argv_free(argv);
			return false;
		}

		bool greedy = pkgconf_fragment_is_greedy(argv[i]);

		PKGCONF_TRACE(client, "processing [%s] greedy=%d", argv[i], greedy);

		if (greedy && i + 1 < argc)
		{
			pkgconf_buffer_t greedybuf = PKGCONF_BUFFER_INITIALIZER;

			pkgconf_buffer_append(&greedybuf, argv[i]);
			pkgconf_buffer_append(&greedybuf, argv[i + 1]);
			pkgconf_fragment_add(client, list, vars, pkgconf_buffer_str(&greedybuf), flags);
			pkgconf_buffer_finalize(&greedybuf);

			/* skip over next arg as we combined them */
			i++;
		}
		else
			pkgconf_fragment_add(client, list, vars, argv[i], flags);
	}

	pkgconf_argv_free(argv);

	return true;
}