#include "cache.h"
#include "dir.h"
#include "pathspec.h"

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * For each pathspec, sets the corresponding entry in the seen[] array
 * (which should be specs items long, i.e. the same size as pathspec)
 * to the nature of the "closest" (i.e. most specific) match found for
 * that pathspec in the index, if it was a closer type of match than
 * the existing entry.  As an optimization, matching is skipped
 * altogether if seen[] already only contains non-zero entries.
 *
 * If seen[] has not already been written to, it may make sense
 * to use find_pathspecs_matching_against_index() instead.
 */
void add_pathspec_matches_against_index(const char **pathspec,
                                        char *seen, int specs)
{
        int num_unmatched = 0, i;

        /*
         * Since we are walking the index as if we were walking the directory,
         * we have to mark the matched pathspec as seen; otherwise we will
         * mistakenly think that the user gave a pathspec that did not match
         * anything.
         */
        for (i = 0; i < specs; i++)
                if (!seen[i])
                        num_unmatched++;
        if (!num_unmatched)
                return;
        for (i = 0; i < active_nr; i++) {
                struct cache_entry *ce = active_cache[i];
                match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, seen);
        }
}

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * This is a one-shot wrapper around add_pathspec_matches_against_index()
 * which allocates, populates, and returns a seen[] array indicating the
 * nature of the "closest" (i.e. most specific) matches which each of the
 * given pathspecs achieves against all items in the index.
 */
char *find_pathspecs_matching_against_index(const char **pathspec)
{
        char *seen;
        int i;

        for (i = 0; pathspec[i];  i++)
                ; /* just counting */
        seen = xcalloc(i, 1);
        add_pathspec_matches_against_index(pathspec, seen, i);
        return seen;
}

/*
 * Check the index to see whether path refers to a submodule, or
 * something inside a submodule.  If the former, returns the path with
 * any trailing slash stripped.  If the latter, dies with an error
 * message.
 */
const char *check_path_for_gitlink(const char *path)
{
        int i, path_len = strlen(path);
        for (i = 0; i < active_nr; i++) {
                struct cache_entry *ce = active_cache[i];
                if (S_ISGITLINK(ce->ce_mode)) {
                        int ce_len = ce_namelen(ce);
                        if (path_len <= ce_len || path[ce_len] != '/' ||
                            memcmp(ce->name, path, ce_len))
                                /* path does not refer to this
                                 * submodule or anything inside it */
                                continue;
                        if (path_len == ce_len + 1) {
                                /* path refers to submodule;
                                 * strip trailing slash */
                                return xstrndup(ce->name, ce_len);
                        } else {
                                die (_("Path '%s' is in submodule '%.*s'"),
                                     path, ce_len, ce->name);
                        }
                }
        }
        return path;
}

/*
 * Dies if the given path refers to a file inside a symlinked
 * directory in the index.
 */
void die_if_path_beyond_symlink(const char *path, const char *prefix)
{
        if (has_symlink_leading_path(path, strlen(path))) {
                int len = prefix ? strlen(prefix) : 0;
                die(_("'%s' is beyond a symbolic link"), path + len);
        }
}

/*
 * Magic pathspec
 *
 * NEEDSWORK: These need to be moved to dir.h or even to a new
 * pathspec.h when we restructure get_pathspec() users to use the
 * "struct pathspec" interface.
 *
 * Possible future magic semantics include stuff like:
 *
 *      { PATHSPEC_NOGLOB, '!', "noglob" },
 *      { PATHSPEC_ICASE, '\0', "icase" },
 *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 *      { PATHSPEC_REGEXP, '\0', "regexp" },
 *
 */
#define PATHSPEC_FROMTOP    (1<<0)

static struct pathspec_magic {
        unsigned bit;
        char mnemonic; /* this cannot be ':'! */
        const char *name;
} pathspec_magic[] = {
        { PATHSPEC_FROMTOP, '/', "top" },
};

/*
 * Take an element of a pathspec and check for magic signatures.
 * Append the result to the prefix.
 *
 * For now, we only parse the syntax and throw out anything other than
 * "top" magic.
 *
 * NEEDSWORK: This needs to be rewritten when we start migrating
 * get_pathspec() users to use the "struct pathspec" interface.  For
 * example, a pathspec element may be marked as case-insensitive, but
 * the prefix part must always match literally, and a single stupid
 * string cannot express such a case.
 */
static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
{
        unsigned magic = 0;
        const char *copyfrom = elt;
        int i;

        if (elt[0] != ':') {
                ; /* nothing to do */
        } else if (elt[1] == '(') {
                /* longhand */
                const char *nextat;
                for (copyfrom = elt + 2;
                     *copyfrom && *copyfrom != ')';
                     copyfrom = nextat) {
                        size_t len = strcspn(copyfrom, ",)");
                        if (copyfrom[len] == ',')
                                nextat = copyfrom + len + 1;
                        else
                                /* handle ')' and '\0' */
                                nextat = copyfrom + len;
                        if (!len)
                                continue;
                        for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
                                if (strlen(pathspec_magic[i].name) == len &&
                                    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
                                        magic |= pathspec_magic[i].bit;
                                        break;
                                }
                        if (ARRAY_SIZE(pathspec_magic) <= i)
                                die("Invalid pathspec magic '%.*s' in '%s'",
                                    (int) len, copyfrom, elt);
                }
                if (*copyfrom != ')')
                        die("Missing ')' at the end of pathspec magic in '%s'", elt);
                copyfrom++;
        } else {
                /* shorthand */
                for (copyfrom = elt + 1;
                     *copyfrom && *copyfrom != ':';
                     copyfrom++) {
                        char ch = *copyfrom;

                        if (!is_pathspec_magic(ch))
                                break;
                        for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
                                if (pathspec_magic[i].mnemonic == ch) {
                                        magic |= pathspec_magic[i].bit;
                                        break;
                                }
                        if (ARRAY_SIZE(pathspec_magic) <= i)
                                die("Unimplemented pathspec magic '%c' in '%s'",
                                    ch, elt);
                }
                if (*copyfrom == ':')
                        copyfrom++;
        }

        if (magic & PATHSPEC_FROMTOP)
                return xstrdup(copyfrom);
        else
                return prefix_path(prefix, prefixlen, copyfrom);
}

/*
 * N.B. get_pathspec() is deprecated in favor of the "struct pathspec"
 * based interface - see pathspec_magic above.
 *
 * Arguments:
 *  - prefix - a path relative to the root of the working tree
 *  - pathspec - a list of paths underneath the prefix path
 *
 * Iterates over pathspec, prepending each path with prefix,
 * and return the resulting list.
 *
 * If pathspec is empty, return a singleton list containing prefix.
 *
 * If pathspec and prefix are both empty, return an empty list.
 *
 * This is typically used by built-in commands such as add.c, in order
 * to normalize argv arguments provided to the built-in into a list of
 * paths to process, all relative to the root of the working tree.
 */
const char **get_pathspec(const char *prefix, const char **pathspec)
{
        const char *entry = *pathspec;
        const char **src, **dst;
        int prefixlen;

        if (!prefix && !entry)
                return NULL;

        if (!entry) {
                static const char *spec[2];
                spec[0] = prefix;
                spec[1] = NULL;
                return spec;
        }

        /* Otherwise we have to re-write the entries.. */
        src = pathspec;
        dst = pathspec;
        prefixlen = prefix ? strlen(prefix) : 0;
        while (*src) {
                *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
                src++;
        }
        *dst = NULL;
        if (!*pathspec)
                return NULL;
        return pathspec;
}