/*
 * fragment.c
 * Management of fragment lists.
 *
 * 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/stdinc.h>
#include <libpkgconf/libpkgconf.h>

/*
 * !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 {
        char *token;
        size_t len;
};

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_should_munge(const char *string, const char *sysroot_dir)
{
        if (*string != '/')
                return false;

        if (sysroot_dir != NULL && strncmp(sysroot_dir, string, strlen(sysroot_dir)))
                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},
                {"-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_terminus(const char *string)
{
        static const struct pkgconf_fragment_check check_fragments[] = {
                {"-Wl,--end-group", 15},
        };

        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);
}

static inline void
pkgconf_fragment_munge(const pkgconf_client_t *client, char *buf, size_t buflen, const char *source, const char *sysroot_dir, unsigned int flags)
{
        *buf = '\0';

        if (!(flags & PKGCONF_PKG_PROPF_UNINSTALLED) || (client->flags & PKGCONF_PKG_PKGF_PKGCONF1_SYSROOT_RULES))
        {
                if (sysroot_dir == NULL)
                        sysroot_dir = pkgconf_tuple_find_global(client, "pc_sysrootdir");

                if (sysroot_dir != NULL && pkgconf_fragment_should_munge(source, sysroot_dir))
                        pkgconf_strlcat(buf, sysroot_dir, buflen);
        }

        pkgconf_strlcat(buf, source, buflen);

        if (*buf == '/' && !(client->flags & PKGCONF_PKG_PKGF_DONT_RELOCATE_PATHS))
                pkgconf_path_relocate(buf, buflen);
}

static inline char *
pkgconf_fragment_copy_munged(const pkgconf_client_t *client, const char *source, unsigned int flags)
{
        char mungebuf[PKGCONF_ITEM_SIZE];
        pkgconf_fragment_munge(client, mungebuf, sizeof mungebuf, source, client->sysroot_dir, flags);
        return strdup(mungebuf);
}

/*
 * !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(const pkgconf_client_t *client, pkgconf_list_t *list, char type, const char *data, bool tail)
{
        pkgconf_fragment_t *frag;

        frag = calloc(1, sizeof(pkgconf_fragment_t));
        frag->type = type;
        frag->data = pkgconf_fragment_copy_munged(client, data, 0);

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

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

/*
 * !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(const pkgconf_client_t *client, pkgconf_list_t *list, const char *string, unsigned int flags)
{
        pkgconf_list_t *target = list;
        pkgconf_fragment_t *frag;

        if (*string == '\0')
                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(string))
                                parent->flags |= PKGCONF_PKG_FRAGF_TERMINATED;

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

        if (strlen(string) > 1 && !pkgconf_fragment_is_special(string))
        {
                frag = calloc(1, sizeof(pkgconf_fragment_t));

                frag->type = *(string + 1);
                frag->data = pkgconf_fragment_copy_munged(client, string + 2, flags);

                PKGCONF_TRACE(client, "added fragment {%c, '%s'} to list @%p", frag->type, frag->data, list);
        }
        else
        {
                frag = calloc(1, sizeof(pkgconf_fragment_t));

                frag->type = 0;
                frag->data = pkgconf_fragment_copy_munged(client, string, flags);

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

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

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 (!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;

        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));

        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);
        }
}

static inline char *
fragment_quote(const pkgconf_fragment_t *frag)
{
        const char *src = frag->data;
        ssize_t outlen = strlen(src) + 10;
        char *out, *dst;

        if (frag->data == NULL)
                return NULL;

        out = dst = calloc(1, outlen);

        for (; *src; src++)
        {
                if (((*src < ' ') ||
                    (*src >= (' ' + (frag->children.head != NULL ? 1 : 0)) && *src < '$') ||
                    (*src > '$' && *src < '(') ||
                    (*src > ')' && *src < '+') ||
                    (*src > ':' && *src < '=') ||
                    (*src > '=' && *src < '@') ||
                    (*src > 'Z' && *src < '\\') ||
#ifndef _WIN32
                    (*src == '\\') ||
#endif
                    (*src > '\\' && *src < '^') ||
                    (*src == '`') ||
                    (*src > 'z' && *src < '~') ||
                    (*src > '~')))
                        *dst++ = '\\';

                *dst++ = *src;

                if ((ptrdiff_t)(dst - out) + 2 > outlen)
                {
                        ptrdiff_t offset = dst - out;
                        outlen *= 2;
                        out = realloc(out, outlen);
                        dst = out + offset;
                }
        }

        *dst = 0;
        return out;
}

static inline size_t
pkgconf_fragment_len(const pkgconf_fragment_t *frag)
{
        size_t len = 1;

        if (frag->type)
                len += 2;

        if (frag->data != NULL)
        {
                pkgconf_node_t *iter;

                char *quoted = fragment_quote(frag);
                len += strlen(quoted);
                free(quoted);

                PKGCONF_FOREACH_LIST_ENTRY(frag->children.head, iter)
                {
                        const pkgconf_fragment_t *child_frag = iter->data;
                        len += pkgconf_fragment_len(child_frag) + 1;
                }
        }

        return len;
}

static size_t
fragment_render_len(const pkgconf_list_t *list, bool escape)
{
        (void) escape;

        size_t out = 1;         /* trailing nul */
        pkgconf_node_t *node;

        PKGCONF_FOREACH_LIST_ENTRY(list->head, node)
        {
                const pkgconf_fragment_t *frag = node->data;
                out += pkgconf_fragment_len(frag);
        }

        return out;
}

static inline size_t
fragment_render_item(const pkgconf_fragment_t *frag, char *bptr, size_t bufremain)
{
        char *base = bptr;
        char *quoted = fragment_quote(frag);
        const pkgconf_node_t *iter;

        if (strlen(quoted) > bufremain)
        {
                free(quoted);
                return 0;
        }

        if (frag->type)
        {
                *bptr++ = '-';
                *bptr++ = frag->type;
        }

        if (quoted != NULL)
        {
                bptr += pkgconf_strlcpy(bptr, quoted, bufremain - (bptr - base));
                free(quoted);
        }

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

                *bptr++ = ' ';
                bptr += fragment_render_item(child_frag, bptr, bufremain - (bptr - base));
        }

        return bptr - base;
}

static void
fragment_render_buf(const pkgconf_list_t *list, char *buf, size_t buflen, bool escape)
{
        (void) escape;

        pkgconf_node_t *node;
        char *bptr = buf;

        memset(buf, 0, buflen);

        PKGCONF_FOREACH_LIST_ENTRY(list->head, node)
        {
                const pkgconf_fragment_t *frag = node->data;
                size_t buf_remaining = buflen - (bptr - buf);
                size_t written = fragment_render_item(frag, bptr, buf_remaining);

                bptr += written;

                if (node->next != NULL)
                        *bptr++ = ' ';
        }
}

static const pkgconf_fragment_render_ops_t default_render_ops = {
        .render_len = fragment_render_len,
        .render_buf = fragment_render_buf
};

/*
 * !doc
 *
 * .. c:function:: size_t pkgconf_fragment_render_len(const pkgconf_list_t *list, bool escape, const pkgconf_fragment_render_ops_t *ops)
 *
 *    Calculates the required memory to store a `fragment list` when rendered as a string.
 *
 *    :param pkgconf_list_t* list: The `fragment list` being rendered.
 *    :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``.
 *    :return: the amount of bytes required to represent the `fragment list` when rendered
 *    :rtype: size_t
 */
size_t
pkgconf_fragment_render_len(const pkgconf_list_t *list, bool escape, const pkgconf_fragment_render_ops_t *ops)
{
        (void) escape;

        ops = ops != NULL ? ops : &default_render_ops;
        return ops->render_len(list, true);
}

/*
 * !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)
 *
 *    Renders a `fragment list` into a buffer.
 *
 *    :param pkgconf_list_t* list: The `fragment list` being rendered.
 *    :param char* buf: The buffer to render the fragment list into.
 *    :param size_t buflen: The length of the buffer.
 *    :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``.
 *    :return: nothing
 */
void
pkgconf_fragment_render_buf(const pkgconf_list_t *list, char *buf, size_t buflen, bool escape, const pkgconf_fragment_render_ops_t *ops)
{
        (void) escape;

        ops = ops != NULL ? ops : &default_render_ops;
        ops->render_buf(list, buf, buflen, true);
}

/*
 * !doc
 *
 * .. c:function:: char *pkgconf_fragment_render(const pkgconf_list_t *list)
 *
 *    Allocate memory and render a `fragment list` into it.
 *
 *    :param pkgconf_list_t* list: The `fragment list` being rendered.
 *    :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``.
 *    :return: An allocated string containing the rendered `fragment list`.
 *    :rtype: char *
 */
char *
pkgconf_fragment_render(const pkgconf_list_t *list, bool escape, const pkgconf_fragment_render_ops_t *ops)
{
        (void) escape;

        size_t buflen = pkgconf_fragment_render_len(list, true, ops);
        char *buf = calloc(1, buflen);

        pkgconf_fragment_render_buf(list, buf, buflen, true, ops);

        return buf;
}

/*
 * !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(const pkgconf_client_t *client, pkgconf_list_t *list, pkgconf_list_t *vars, const char *value, unsigned int flags)
{
        int i, ret, argc;
        char **argv;
        char *repstr = pkgconf_tuple_parse(client, vars, value, flags);

        PKGCONF_TRACE(client, "post-subst: [%s] -> [%s]", value, repstr);

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

        for (i = 0; i < argc; i++)
        {
                PKGCONF_TRACE(client, "processing %s", argv[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);
                        free(repstr);
                        return false;
                }

                pkgconf_fragment_add(client, list, argv[i], flags);
        }

        pkgconf_argv_free(argv);
        free(repstr);

        return true;
}