/*
 * tuple.c
 * management of key->value tuples
 *
 * Copyright (c) 2011, 2012 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/stdinc.h>
#include <libpkgconf/libpkgconf.h>

/*
 * !doc
 *
 * libpkgconf `tuple` module
 * =========================
 *
 * The `tuple` module provides key-value mappings backed by a linked list.  The key-value
 * mapping is mainly used for variable substitution when parsing .pc files.
 *
 * There are two sets of mappings: a ``pkgconf_pkg_t`` specific mapping, and a `global` mapping.
 * The `tuple` module provides convenience wrappers for managing the `global` mapping, which is
 * attached to a given client object.
 */

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_add_global(pkgconf_client_t *client, const char *key, const char *value)
 *
 *    Defines a global variable, replacing the previous declaration if one was set.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to modify.
 *    :param char* key: The key for the mapping (variable name).
 *    :param char* value: The value for the mapped entry.
 *    :return: nothing
 */
void
pkgconf_tuple_add_global(pkgconf_client_t *client, const char *key, const char *value)
{
        pkgconf_tuple_add(client, &client->global_vars, key, value, false, 0);
}

static pkgconf_tuple_t *
lookup_global_tuple(const pkgconf_client_t *client, const char *key)
{
        pkgconf_node_t *node;

        PKGCONF_FOREACH_LIST_ENTRY(client->global_vars.head, node)
        {
                pkgconf_tuple_t *tuple = node->data;

                if (!strcmp(tuple->key, key))
                        return tuple;
        }

        return NULL;
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_find_global(const pkgconf_client_t *client, const char *key)
 *
 *    Looks up a global variable.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to access.
 *    :param char* key: The key or variable name to look up.
 *    :return: the contents of the variable or ``NULL``
 *    :rtype: char *
 */
char *
pkgconf_tuple_find_global(const pkgconf_client_t *client, const char *key)
{
        pkgconf_tuple_t *tuple;

        tuple = lookup_global_tuple(client, key);
        if (tuple == NULL)
                return NULL;

        return tuple->value;
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_free_global(pkgconf_client_t *client)
 *
 *    Delete all global variables associated with a pkgconf client object.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to modify.
 *    :return: nothing
 */
void
pkgconf_tuple_free_global(pkgconf_client_t *client)
{
        pkgconf_tuple_free(&client->global_vars);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_define_global(pkgconf_client_t *client, const char *kv)
 *
 *    Parse and define a global variable.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to modify.
 *    :param char* kv: The variable in the form of ``key=value``.
 *    :return: nothing
 */
void
pkgconf_tuple_define_global(pkgconf_client_t *client, const char *kv)
{
        char *workbuf = strdup(kv);
        char *value;
        pkgconf_tuple_t *tuple;

        value = strchr(workbuf, '=');
        if (value == NULL)
                goto out;

        *value++ = '\0';

        tuple = pkgconf_tuple_add(client, &client->global_vars, workbuf, value, false, 0);
        if (tuple != NULL)
                tuple->flags = PKGCONF_PKG_TUPLEF_OVERRIDE;

out:
        free(workbuf);
}

static void
pkgconf_tuple_find_delete(pkgconf_list_t *list, const char *key)
{
        pkgconf_node_t *node, *next;

        PKGCONF_FOREACH_LIST_ENTRY_SAFE(list->head, next, node)
        {
                pkgconf_tuple_t *tuple = node->data;

                if (!strcmp(tuple->key, key))
                {
                        pkgconf_tuple_free_entry(tuple, list);
                        return;
                }
        }
}

static char *
dequote(const char *value)
{
        char *buf = calloc(1, (strlen(value) + 1) * 2);
        char *bptr = buf;
        const char *i;
        char quote = 0;

        if (*value == '\'' || *value == '"')
                quote = *value;

        for (i = value; *i != '\0'; i++)
        {
                if (*i == '\\' && quote && *(i + 1) == quote)
                {
                        i++;
                        *bptr++ = *i;
                }
                else if (*i != quote)
                        *bptr++ = *i;
        }

        return buf;
}

static const char *
find_sysroot(const pkgconf_client_t *client, pkgconf_list_t *vars)
{
        const char *sysroot_dir;

        sysroot_dir = pkgconf_tuple_find(client, vars, "pc_sysrootdir");
        if (sysroot_dir == NULL)
                sysroot_dir = client->sysroot_dir;

        return sysroot_dir;
}

static bool
should_rewrite_sysroot(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *buf, unsigned int flags)
{
        const char *sysroot_dir;

        if (flags & PKGCONF_PKG_PROPF_UNINSTALLED && !(client->flags & PKGCONF_PKG_PKGF_FDO_SYSROOT_RULES))
                return false;

        sysroot_dir = find_sysroot(client, vars);
        if (sysroot_dir == NULL)
                return false;

        if (*buf != '/')
                return false;

        if (!strcmp(sysroot_dir, "/"))
                return false;

        if (strlen(buf) <= strlen(sysroot_dir))
                return false;

        if (strstr(buf + strlen(sysroot_dir), sysroot_dir) == NULL)
                return false;

        return true;
}

/*
 * !doc
 *
 * .. c:function:: pkgconf_tuple_t *pkgconf_tuple_add(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key, const char *value, bool parse)
 *
 *    Optionally parse and then define a variable.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to access.
 *    :param pkgconf_list_t* list: The variable list to add the new variable to.
 *    :param char* key: The name of the variable being added.
 *    :param char* value: The value of the variable being added.
 *    :param bool parse: Whether or not to parse the value for variable substitution.
 *    :return: a variable object
 *    :rtype: pkgconf_tuple_t *
 */
pkgconf_tuple_t *
pkgconf_tuple_add(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key, const char *value, bool parse, unsigned int flags)
{
        char *dequote_value;
        pkgconf_tuple_t *tuple = calloc(1, sizeof(pkgconf_tuple_t));

        pkgconf_tuple_find_delete(list, key);

        dequote_value = dequote(value);

        tuple->key = strdup(key);
        if (parse)
                tuple->value = pkgconf_tuple_parse(client, list, dequote_value, flags);
        else
                tuple->value = strdup(dequote_value);

        PKGCONF_TRACE(client, "adding tuple to @%p: %s => %s (parsed? %d)", list, key, tuple->value, parse);

        pkgconf_node_insert(&tuple->iter, tuple, list);

        free(dequote_value);

        return tuple;
}

/*
 * !doc
 *
 * .. c:function:: char *pkgconf_tuple_find(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key)
 *
 *    Look up a variable in a variable list.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to access.
 *    :param pkgconf_list_t* list: The variable list to search.
 *    :param char* key: The variable name to search for.
 *    :return: the value of the variable or ``NULL``
 *    :rtype: char *
 */
char *
pkgconf_tuple_find(const pkgconf_client_t *client, pkgconf_list_t *list, const char *key)
{
        pkgconf_node_t *node;
        pkgconf_tuple_t *global_tuple;

        global_tuple = lookup_global_tuple(client, key);
        if (global_tuple != NULL && global_tuple->flags & PKGCONF_PKG_TUPLEF_OVERRIDE)
                return global_tuple->value;

        PKGCONF_FOREACH_LIST_ENTRY(list->head, node)
        {
                pkgconf_tuple_t *tuple = node->data;

                if (!strcmp(tuple->key, key))
                        return tuple->value;
        }

        if (global_tuple != NULL)
                return global_tuple->value;

        return NULL;
}

/*
 * !doc
 *
 * .. c:function:: char *pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value, unsigned int flags)
 *
 *    Parse an expression for variable substitution.
 *
 *    :param pkgconf_client_t* client: The pkgconf client object to access.
 *    :param pkgconf_list_t* list: The variable list to search for variables (along side the global variable list).
 *    :param char* value: The ``key=value`` string to parse.
 *    :param uint flags: Any flags to consider while parsing.
 *    :return: the variable data with any variables substituted
 *    :rtype: char *
 */
char *
pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value, unsigned int flags)
{
        char buf[PKGCONF_BUFSIZE];
        const char *ptr;
        char *bptr = buf;

        if (!(client->flags & PKGCONF_PKG_PKGF_FDO_SYSROOT_RULES) &&
                (!(flags & PKGCONF_PKG_PROPF_UNINSTALLED) || (client->flags & PKGCONF_PKG_PKGF_PKGCONF1_SYSROOT_RULES)))
        {
                if (*value == '/' && client->sysroot_dir != NULL && strncmp(value, client->sysroot_dir, strlen(client->sysroot_dir)))
                        bptr += pkgconf_strlcpy(buf, client->sysroot_dir, sizeof buf);
        }

        for (ptr = value; *ptr != '\0' && bptr - buf < PKGCONF_BUFSIZE; ptr++)
        {
                if (*ptr != '$' || (*ptr == '$' && *(ptr + 1) != '{'))
                        *bptr++ = *ptr;
                else if (*(ptr + 1) == '{')
                {
                        char varname[PKGCONF_ITEM_SIZE];
                        char *vend = varname + PKGCONF_ITEM_SIZE - 1;
                        char *vptr = varname;
                        const char *pptr;
                        char *kv, *parsekv;

                        *vptr = '\0';

                        for (pptr = ptr + 2; *pptr != '\0'; pptr++)
                        {
                                if (*pptr != '}')
                                {
                                        if (vptr < vend)
                                                *vptr++ = *pptr;
                                        else
                                        {
                                                *vptr = '\0';
                                                break;
                                        }
                                }
                                else
                                {
                                        *vptr = '\0';
                                        break;
                                }
                        }

                        PKGCONF_TRACE(client, "lookup tuple %s", varname);

                        size_t remain = PKGCONF_BUFSIZE - (bptr - buf);
                        ptr += (pptr - ptr);
                        kv = pkgconf_tuple_find_global(client, varname);
                        if (kv != NULL)
                        {
                                size_t nlen = pkgconf_strlcpy(bptr, kv, remain);
                                if (nlen > remain)
                                {
                                        pkgconf_warn(client, "warning: truncating very long variable to 64KB\n");

                                        bptr = buf + (PKGCONF_BUFSIZE - 1);
                                        break;
                                }

                                bptr += nlen;
                        }
                        else
                        {
                                kv = pkgconf_tuple_find(client, vars, varname);

                                if (kv != NULL)
                                {
                                        size_t nlen;

                                        parsekv = pkgconf_tuple_parse(client, vars, kv, flags);
                                        nlen = pkgconf_strlcpy(bptr, parsekv, remain);
                                        free(parsekv);

                                        if (nlen > remain)
                                        {
                                                pkgconf_warn(client, "warning: truncating very long variable to 64KB\n");

                                                bptr = buf + (PKGCONF_BUFSIZE - 1);
                                                break;
                                        }

                                        bptr += nlen;
                                }
                        }
                }
        }

        *bptr = '\0';

        /*
         * Sigh.  Somebody actually attempted to use freedesktop.org pkg-config's broken sysroot support,
         * which was written by somebody who did not understand how sysroots are supposed to work.  This
         * results in an incorrect path being built as the sysroot will be prepended twice, once explicitly,
         * and once by variable expansion (the pkgconf approach).  We could simply make ${pc_sysrootdir} blank,
         * but sometimes it is necessary to know the explicit sysroot path for other reasons, so we can't really
         * do that.
         *
         * As a result, we check to see if ${pc_sysrootdir} is prepended as a duplicate, and if so, remove the
         * prepend.  This allows us to handle both our approach and the broken freedesktop.org implementation's
         * approach.  Because a path can be shorter than ${pc_sysrootdir}, we do some checks first to ensure it's
         * safe to skip ahead in the string to scan for our sysroot dir.
         *
         * Finally, we call pkgconf_path_relocate() to clean the path of spurious elements.
         *
         * New in 1.9: Only attempt to rewrite the sysroot if we are not processing an uninstalled package.
         */
        if (should_rewrite_sysroot(client, vars, buf, flags))
        {
                char cleanpath[PKGCONF_ITEM_SIZE];
                const char *sysroot_dir = find_sysroot(client, vars);

                pkgconf_strlcpy(cleanpath, buf + strlen(sysroot_dir), sizeof cleanpath);
                pkgconf_path_relocate(cleanpath, sizeof cleanpath);

                return strdup(cleanpath);
        }

        return strdup(buf);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_free_entry(pkgconf_tuple_t *tuple, pkgconf_list_t *list)
 *
 *    Deletes a variable object, removing it from any variable lists and releasing any memory associated
 *    with it.
 *
 *    :param pkgconf_tuple_t* tuple: The variable object to release.
 *    :param pkgconf_list_t* list: The variable list the variable object is attached to.
 *    :return: nothing
 */
void
pkgconf_tuple_free_entry(pkgconf_tuple_t *tuple, pkgconf_list_t *list)
{
        pkgconf_node_delete(&tuple->iter, list);

        free(tuple->key);
        free(tuple->value);
        free(tuple);
}

/*
 * !doc
 *
 * .. c:function:: void pkgconf_tuple_free(pkgconf_list_t *list)
 *
 *    Deletes a variable list and any variables attached to it.
 *
 *    :param pkgconf_list_t* list: The variable list to delete.
 *    :return: nothing
 */
void
pkgconf_tuple_free(pkgconf_list_t *list)
{
        pkgconf_node_t *node, *next;

        PKGCONF_FOREACH_LIST_ENTRY_SAFE(list->head, next, node)
                pkgconf_tuple_free_entry(node->data, list);

        pkgconf_list_zero(list);
}