cp_mv.c

Go to the documentation of this file.

/************************************************************************
 * Copyright (C) 2007-2009 Philipp Marek.
 *
 * This program is free software;  you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 ************************************************************************/

#include <fcntl.h>
#include <search.h>

#include "global.h"
#include "cp_mv.h"
#include "status.h"
#include "est_ops.h"
#include "url.h"
#include "checksum.h"
#include "options.h"
#include "props.h"
#include "cache.h"
#include "helper.h"
#include "waa.h"


/* Or should for dirlist just the raw data be showed - common_files, 
 * files_in_new_dir? */

/* for internal use only, not visible
 *
 * \section cp_mv_data Storing and reading the needed data
 *
 * For copy/move detection we need fast access to other files with the same 
 * or similar data.
 * - To find identical files we just take a GDBM database, indexed by the 
 *   MD5, and having a (\c \\0 separated) list of filenames.
 *   Why GDBM?
 *   - For partial commits we need to remove/use parts of the data; a 
 *   textfile would have to be completely re-written.
 * - We need the list of copies/moves identified by the user.
 *   - This should be quickly editable
 *   - No big blobs to stay after a commit (empty db structure?)
 *   - Using an file/symlink in the WAA for the new entry seems bad. We'd 
 *   have to try to find such an file/symlink for each committed entry.
 *     - But might be fast by just doing readlink()? = a single syscall
 *     - The number of copy-entries is typically small.
 *     - Easy to remove
 *     - Uses inodes, though
 *     - Easily readable - just points to source
 *   - GDBM?
 *     - easy to update and delete
 *     - might uses some space
 *     - a single entry
 *     - not as easy to read
 *   - Text-file is out, because of random access for partial commits.
 * - Maybe we should write the manber hash of the first two blocks there, 
 *   too? -- No, manber-hashes would be done on all files at once.
 *
 *
 * Facts:
 * - we have to copy directory structures *after* waa__input_tree(), but 
 *   before waa__partial_update().
 *   - While running waa__input_tree() the source tree might still be in 
 *   work
 *   - While running waa__partial_update() the "old" data of the copied 
 *   entries might already be destroyed
 *   - But here we don't know the new entries yet!
 * - We have to do *all* entries there
 *   - As we do not yet know which part of the tree we'll be working with
 * - We must not save these temporary entries
 *   - Either mark FT_IGNORE
 *   - Or don't load the copies for actions calling waa__output_tree().
 *   - But what about the property functions? They need access to copied 
 *   entries.
 *     - Can do the entries as RF_ADD, as now.
 *
 * So a "copy" does copy all entries for the list, too; but that means that 
 * a bit more data has to be written out.
 *   
 * */

/* As the temporary databases (just indizes for detection) are good only 
 * for a single run, we can easily store the address directly. For the real 
 * copy-from db we have to use the path.
 *
 * Temporary storage:
 *   value.dptr=sts;
 *   value.dsize=sizeof(sts);
 * Persistent:
 *   value.dptr=path;
 *   value.dsize=sts->path_len;
 *
 * I don't think we want to keep these files up-to-date ... would mean 
 * constant runtime overhead. */


#define MAX_DUPL_ENTRIES (HASH__LIST_MAX -1)

#if 0

#define MIN_FILE_SIZE (32)
#endif


int copydetect_count;


struct cm___candidate_t {
    struct estat *sts;
    int matches_where;
    int match_count;
};


typedef datum (cm___to_datum_t)(const struct estat *sts);
cm___to_datum_t cm___md5_datum;
cm___to_datum_t cm___inode_datum;
cm___to_datum_t cm___name_datum;
struct cm___match_t;

typedef int (cm___register_fn)(struct estat *, struct cm___match_t *);
typedef int (cm___get_list_fn)(struct estat *, struct cm___match_t *,
        struct cm___candidate_t **, int *count);
typedef char* (cm___format_fn)(struct cm___match_t * match,
        struct cm___candidate_t *cand);


cm___register_fn cm___hash_register;
cm___get_list_fn cm___hash_list;
cm___get_list_fn cm___match_children;
cm___format_fn cm___output_pct;


struct cm___match_t {
    char name[8];
    mode_t entry_type;
    int is_expensive:1;
    int is_enabled:1;

    cm___register_fn *insert;
    cm___get_list_fn *get_list;
    cm___format_fn *format;

    cm___to_datum_t *to_key;
    char filename[8];
    hash_t db;
    datum key;
};

enum cm___match_e {
    CM___NAME_F=0,
    CM___NAME_D,
    CM___DIRLIST,
};

struct cm___match_t cm___match_array[]=
{
    [CM___NAME_F] = { .name="name", .to_key=cm___name_datum, 
        .insert=cm___hash_register, .get_list=cm___hash_list,
        .entry_type=S_IFREG,  .filename=WAA__FILE_NAME_EXT},
    [CM___NAME_D] = { .name="name", .to_key=cm___name_datum, 
        .insert=cm___hash_register, .get_list=cm___hash_list,
        .entry_type=S_IFDIR,  .filename=WAA__DIR_NAME_EXT},

    [CM___DIRLIST] = { .name="dirlist", 
        .get_list=cm___match_children, .format=cm___output_pct,
        .entry_type=S_IFDIR, },

    { .name="md5", .to_key=cm___md5_datum, .is_expensive=1,
        .insert=cm___hash_register, .get_list=cm___hash_list,
        .entry_type=S_IFREG, .filename=WAA__FILE_MD5s_EXT},

    { .name="inode", .to_key=cm___inode_datum, 
        .insert=cm___hash_register, .get_list=cm___hash_list,
        .entry_type=S_IFDIR, .filename=WAA__FILE_INODE_EXT},
    { .name="inode", .to_key=cm___inode_datum, 
        .insert=cm___hash_register, .get_list=cm___hash_list,
        .entry_type=S_IFREG, .filename=WAA__DIR_INODE_EXT},
};
#define CM___MATCH_NUM (sizeof(cm___match_array)/sizeof(cm___match_array[0]))


datum cm___md5_datum(const struct estat *sts)
{
    datum d;

    d.dsize=APR_MD5_DIGESTSIZE*2+1;
    d.dptr=cs__md5tohex_buffered(sts->md5);
    return d;
}


datum cm___name_datum(const struct estat *sts)
{
    datum d;

    d.dptr=sts->name;
    /* We have only the full path length stored. */
    d.dsize=strlen(d.dptr)+1;
    return d;
}


datum cm___inode_datum(const struct estat *sts)
{
    static struct { ino_t ino; dev_t dev; } tmp;
    datum d;

    tmp.ino=sts->st.ino;
    tmp.dev=sts->st.dev;
    d.dptr=(char*)&tmp;
    d.dsize=sizeof(tmp);
    return d;
}


static int cm___cand_compare(const void *_a, const void *_b)
{
    const struct cm___candidate_t *a=_a;
    const struct cm___candidate_t *b=_b;
    return a->sts - b->sts;
}


static int cm___cand_comp_count(const void *_a, const void *_b)
{
    const struct cm___candidate_t *a=_a;
    const struct cm___candidate_t *b=_b;
    return a->match_count - b->match_count;
}


int cm___hash_register(struct estat *sts, struct cm___match_t *match)
{
    int status;


    status=hsh__insert_pointer( match->db, 
            (match->to_key)(sts), sts);

    /* If there is no more space available ... just ignore it. */
    if (status == EFBIG)
        status=0;
    return status;
}


int cm___match_children(struct estat *sts, struct cm___match_t *match,
        struct cm___candidate_t **list, int *found)
{
    int status;
    /* We take a fair bit more, to get *all* (or at least most) possible 
     * matches. */
    static struct cm___candidate_t similar_dirs[MAX_DUPL_ENTRIES*4];
    struct cm___candidate_t *cur, tmp_cand={0};
    size_t simil_dir_count;
    int common;
    struct estat **children, *curr;
    struct estat **others, *other_dir;
    int other_count, i;
    datum key;
    struct cm___match_t *name_match;


    status=0;
    DEBUGP("child matching for %s", sts->name);

    /* No children => cannot be matched */
    if (!sts->entry_count) goto ex;

    simil_dir_count=0;

    children=sts->by_inode;
    while (*children)
    {
        curr=*children;
        /* Find entries with the same name. Depending on the type of the entry  
         * we have to look in one of the two hashes. */
        if (S_ISDIR(curr->st.mode))
            name_match=cm___match_array+CM___NAME_D;
        else if (S_ISREG(curr->st.mode))
            name_match=cm___match_array+CM___NAME_F;
        else goto next_child;


        key=(name_match->to_key)(curr);
        status=hsh__list_get(name_match->db, key, &key, &others, &other_count);


        /* If there are too many entries with the same name, we ignore this 
         * hint.  */
        if (status != ENOENT && other_count && 
                other_count<MAX_DUPL_ENTRIES)
        {
            for(i=0; i<other_count; i++)
            {
            /* Now we don't take the entry with the same name, but it's parent.  
             * As the root entry hopefully never matches we don't need to check 
             * for NULL.
             * */

                tmp_cand.sts=others[i]->parent;

                cur=lsearch(&tmp_cand, similar_dirs, &simil_dir_count, 
                        sizeof(similar_dirs[0]), cm___cand_compare);
                cur->match_count++;
                DEBUGP("dir %s has count %d", cur->sts->name, cur->match_count);

                BUG_ON(simil_dir_count > sizeof(similar_dirs)/sizeof(similar_dirs[0]));
            }
        }

next_child:
        children++;
    }

    /* Now do the comparisions. */
    for(i=0; i<simil_dir_count; i++)
    {
        common=0;
        other_dir=similar_dirs[i].sts;

        int both(struct estat *a, struct estat*b) { common++; return 0; }
        STOPIF( ops__correlate_dirs(sts, other_dir,
                    NULL, both, NULL, NULL), NULL);

        /* For directories with more than 2**32/1000 (~4M) *common* entries we 
         * get an overflow here. But I think that's not important currently :-) 
         * */
        similar_dirs[i].match_count = 
            1000*common/(sts->entry_count + other_dir->entry_count - common);
    }

    /* Now sort, and return a few. */
    qsort( similar_dirs, simil_dir_count, sizeof(similar_dirs[0]), 
            cm___cand_comp_count);

    *found=simil_dir_count > HASH__LIST_MAX ? HASH__LIST_MAX : simil_dir_count;
    *list=similar_dirs;

ex:
    return status;
}


int cm___hash_list(struct estat *sts, struct cm___match_t *match,
        struct cm___candidate_t **output, int *found)
{
    int status;
    static struct cm___candidate_t arr[MAX_DUPL_ENTRIES];
    struct estat **list;
    int i;

    match->key=(match->to_key)(sts);
    status=hsh__list_get(match->db, match->key, &match->key, &list, found);

    if (status == 0)
    {
        for(i=0; i<*found; i++)
        {
            memset(arr+i, 0, sizeof(*arr));
            arr[i].sts=list[i];
        }
        *output=arr;
    }

    return status;
}


char* cm___output_pct(struct cm___match_t *match, 
        struct cm___candidate_t *cand)
{
    static char buffer[8];

    BUG_ON(cand->match_count > 1000 || cand->match_count < 0);

    sprintf(buffer, "=%d.%1d%%",
            cand->match_count/10, cand->match_count % 10);

    return buffer;
}


int cm___register_entry(struct estat *sts)
{
    int status;
    int i;
    struct cm___match_t *match;


    status=0;
    if (!(sts->entry_status & FS_NEW))
    {
        for(i=0; i<CM___MATCH_NUM; i++)
        {
            match=cm___match_array+i;
            /* We need the original value (st.mode). estat::local_mode_packed 
             * would be 0 for a deleted node. */
            if (match->is_enabled && match->insert &&
                    (sts->st.mode & S_IFMT) == match->entry_type )
            {
                STOPIF( (match->insert)(sts, match), NULL);
                DEBUGP("inserted %s for %s", sts->name, match->name);
            }
        }
    }

ex:
    return status;
}


static int cm___match(struct estat *entry)
{   
    int status;
    char *path, *formatted;
    int i, count, have_match, j, overflows;
    struct estat *sts;
    struct cm___match_t *match;
    struct cm___candidate_t candidates[HASH__LIST_MAX*CM___MATCH_NUM];
    struct cm___candidate_t *cur, *list;
    size_t candidate_count;
    FILE *output=stdout;


    /* #error doesn't work with sizeof() ?
     * But doesn't matter much, this gets removed by the compiler. */
    BUG_ON(sizeof(candidates[0].matches_where) *4 < CM___MATCH_NUM,
            "Wrong datatype chosen for matches_where.");


    formatted=NULL;
    status=0;
    candidate_count=0;
    overflows=0;
    path=NULL;

    /* Down below status will get the value ENOENT from the hsh__list_get() 
     * lookups; we change it back to 0 shortly before leaving. */

    for(i=0; i<CM___MATCH_NUM; i++)
    {
        match=cm___match_array+i;

        /* Avoid false positives. */
        if ((entry->st.mode & S_IFMT) != match->entry_type)
            continue;

        /* \todo Loop if too many for a single call. */
        status=match->get_list(entry, match, &list, &count);

        /* ENOENT = nothing to see */
        if (status == ENOENT) continue;

        STOPIF(status, NULL);

        if (count > MAX_DUPL_ENTRIES)
        {
            /* We show one less than we store, so we have the overflow 
             * information.  */
            overflows++;
            count=MAX_DUPL_ENTRIES;
        }

        for(j=0; j<count; j++)
        {
            /* We could do insertion sort into the candidate array here; 
             * bsearch() sadly only finds identical, and lsearch() does unsorted 
             * arrays only.
             *
             * We just use lsearch() - that keeps code size small. */
            cur=lsearch(list+j, candidates, &candidate_count, 
                    sizeof(candidates[0]), cm___cand_compare);

            BUG_ON(candidate_count > sizeof(candidates)/sizeof(candidates[0]));

            cur->matches_where |= 1 << i;

            /* Copy dirlist value */
            if (i == CM___DIRLIST)
                cur->match_count=list[j].match_count;

            DEBUGP("got %s for %s => 0x%X",
                    cur->sts->name, match->name, cur->matches_where);
        }
    }

    status=0;

    if (candidate_count)
    {
        copydetect_count++;

        STOPIF( ops__build_path(&path, entry), NULL);
        STOPIF( hlp__format_path(entry, path, &formatted), NULL);

        /* Print header line for this file. */
        STOPIF_CODE_EPIPE( fprintf(output, "%s\n", formatted), NULL);

        /* Output list of matches */
        for(j=0; j<candidate_count; j++)
        {
            sts=candidates[j].sts;
            have_match=0;

            STOPIF_CODE_EPIPE( fputs("  ", output), NULL);

            for(i=0; i<CM___MATCH_NUM; i++)
            {
                if (candidates[j].matches_where & (1 << i))
                {
                    match=cm___match_array+i;

                    if (have_match)
                        STOPIF_CODE_EPIPE( fputs(",", output), NULL);
                    have_match=1;

                    STOPIF_CODE_EPIPE( fputs(match->name, output), NULL);
                    if (opt__is_verbose()>0 && match->format)
                        STOPIF_CODE_EPIPE( 
                                fputs( match->format(match, candidates+j), output), 
                                NULL);
                }
            }

            STOPIF( ops__build_path(&path, sts), NULL);
            STOPIF( hlp__format_path(sts, path, &formatted), NULL);
            STOPIF_CODE_EPIPE( fprintf(output, ":%s\n", formatted), NULL);
        }


        if (overflows)
            STOPIF_CODE_EPIPE( fputs("  ...\n", output), NULL);
    }
    else
    {
        /* cache might be overwritten again when we're here. */
        STOPIF( ops__build_path(&path, entry), NULL);

        if (opt__is_verbose() > 0)
        {
            STOPIF( hlp__format_path(entry, path, &formatted), NULL);
            STOPIF_CODE_EPIPE( fprintf(output, 
                        "- No copyfrom relation found for %s\n", 
                        formatted), NULL);
        }
        else
            DEBUGP("No sources found for %s", path);
    }

    STOPIF_CODE_EPIPE( fflush(output), NULL);

ex:
    return status;
}


int cm__find_dir_source(struct estat *dir)
{
    int status;
    status=0;

    STOPIF( cm___match( dir ), NULL);

ex:
    return status;
}


int cm__find_file_source(struct estat *file)
{
    int status;
    char *path;


    status=0;
    STOPIF( ops__build_path(&path, file), NULL);
    DEBUGP("finding source of %s", file->name);

    STOPIF( cs__compare_file(file, path, NULL), NULL);
    /* TODO: EPIPE and similar for output */

    STOPIF( cm___match( file ), NULL);

ex:
    return status;
}



int cm__find_copied(struct estat *root)
{
    int status;
    struct estat *sts, **child;


    status=0;
    child=root->by_inode;
    if (!child) goto ex;

    while (*child)
    {
        sts=*child;
        /* Should we try to associate the directory after all children have been 
         * done? We could simply take a look which parent the children's sources 
         * point to ...
         *
         * Otherwise, if there's some easy way to see the source of a directory, 
         * we could maybe save some searching for all children.... */
        if (sts->entry_status & FS_NEW)
        {
            switch (sts->st.mode & S_IFMT)
            {
                case S_IFDIR:
                    STOPIF( cm__find_dir_source(sts), NULL);
                    break;
                case S_IFLNK:
                case S_IFREG:
                    STOPIF( cm__find_file_source(sts), NULL);
                    break;
                default:
                    DEBUGP("Don't handle entry %s", sts->name);
            }
        }

        if (S_ISDIR(sts->st.mode) && 
                (sts->entry_status & (FS_CHILD_CHANGED | FS_CHANGED)) )
            STOPIF( cm__find_copied(sts), NULL);

        child++;
    }

ex:
    return status;
}


int cm__detect(struct estat *root, int argc, char *argv[])
{
    int status, st2;
    char **normalized;
    int i;
    struct cm___match_t *match;
    hash_t hash;


    /* Operate recursively. */
    opt_recursive++;
    /* But do not allow to get current MD5s - we need the data from the 
     * repository. */
    opt__set_int(OPT__CHANGECHECK, PRIO_MUSTHAVE, CHCHECK_NONE);

    STOPIF( waa__find_common_base(argc, argv, &normalized), NULL);

    STOPIF( url__load_list(NULL, 0), NULL);


    for(i=0; i<CM___MATCH_NUM; i++)
    {
        match=cm___match_array+i;

        match->is_enabled= !match->is_expensive || 
            opt__get_int(OPT__COPYFROM_EXP);

        if (!match->filename[0]) continue;

        DEBUGP("open hash for %s as %s", match->name, match->filename);

        /* Create database file for WC root. */
        STOPIF( hsh__new(wc_path, match->filename, 
                    HASH_TEMPORARY, & match->db), NULL);
    }


    /* We read all entries, and show some progress. */
    status=waa__read_or_build_tree(root, argc, normalized, argv, 
            cm___register_entry, 1);
    if (status == -ENOENT)
        STOPIF(status, "!No committed working copy found.");
    STOPIF(status, NULL);


    copydetect_count=0;

    STOPIF( cm__find_copied(root), NULL);

    if (!copydetect_count)
        STOPIF_CODE_EPIPE( printf("No copyfrom relations found.\n"), NULL);
    else if (opt__is_verbose() > 0)
        STOPIF_CODE_EPIPE( printf("%d copyfrom relation%s found.\n",
                    copydetect_count, copydetect_count == 1 ? "" : "s"), NULL);

ex:
    for(i=0; i<CM___MATCH_NUM; i++)
    {
        hash=cm___match_array[i].db;
        cm___match_array[i].db=NULL;
        if (hash)
        {
            st2=hsh__close(hash, status);
            STOPIF_CODE_ERR( st2 && !status, st2, NULL);
        }
    }

    return status;
}


int cm___string_to_rev_path(char *string, char **out_url, svn_revnum_t *orev)
{
    char *path;
    svn_revnum_t rev;

    /* Reserved for future use */
    if (string[0] != '0' || 
            string[1] != ' ') goto inval;
    string+=2;

    rev=strtol(string, &path, 10);
    if (orev) *orev=rev;
    if (string == path) goto inval;

    if (!isspace(*path)) goto inval;

    path=hlp__skip_ws(path);
    *out_url=path;

    DEBUGP("string parsed to r%llu of %s", (t_ull)rev, path);
    return 0;

inval:
    DEBUGP("cannot parse %s", string);
    return EINVAL;
}


int cm___rev_path_to_string(char *url, svn_revnum_t revision, char **string)
{
    int status;
    static struct cache_entry_t *c=NULL;
    int buflen, used;
    char *buffer;


    /* We need to prepend a revision number, and a space.
     * We could do a log10(), but I don't think that's necessary ...
     * even log2l() (which is a single instruction on some processors) uses 
     * floating point operations here. */
    buflen=10 + 1 + strlen(url) + 1;
    STOPIF( cch__entry_set( &c, 0, NULL, buflen, 0, &buffer), NULL);

    used=snprintf(buffer, buflen, "0 %llu %s", (t_ull)revision, url);
    BUG_ON(used >= buflen);

    *string=buffer;

ex:
    return status;
}


int cm___absolute_path(char *path, char **output)
{
    static struct cache_t *cache;
    int status, len;
    char *cp;

    STOPIF( cch__new_cache(&cache, 8), NULL);
    STOPIF( cch__add(cache, 0, NULL, 
                //              wc_path_len + 1 + strlen(path) + 1, &cp), NULL);
        start_path_len + 1 + strlen(path) + 1, &cp), NULL);
    DEBUGP("norm from: %s", path);
    hlp__pathcopy(cp, &len, path, NULL);
    DEBUGP("norm to: %s", cp);

    BUG_ON(len > cache->entries[cache->lru]->len);

    *output=cp;

ex:
    return status;
}


inline int cm___not_below_wcpath(char *path, char **out)
{
    if (strncmp(path, wc_path, wc_path_len) != 0 ||
            path[wc_path_len] != PATH_SEPARATOR)
        return EINVAL;

    *out=path+wc_path_len+1;
    return 0;
}




int cm___dump_list(FILE *output, int argc, char *normalized[])
{
    int status;
    hash_t db;
    datum key, value;
    int have;
    char *path;
    svn_revnum_t rev;


    /* TODO: Use some filter, eg. by pathnames. */
    db=NULL;

    /* Create database file for WC root. */
    status=hsh__new(wc_path, WAA__COPYFROM_EXT, GDBM_READER, &db);
    if (status==ENOENT)
    {
        status=0;
        goto no_copyfrom;
    }

    have=0;
    status=hsh__first(db, &key);
    while (status == 0)
    {
        STOPIF( hsh__fetch(db, key, &value), NULL);

        /* The . at the end is suppressed; therefore we print it from the 
         * second dataset onwards.  */
        if (have)
            status=fputs(".\n", output);

        STOPIF( cm___string_to_rev_path( value.dptr, &path, &rev), NULL);

        status |= fprintf(output, "%s\n%s\n", path, key.dptr);
        IF_FREE(value.dptr);

        STOPIF_CODE_ERR( status < 0, -EPIPE, "output error");

        status=hsh__next(db, &key, &key);
        have++;
    }

    if (!have)
    {
no_copyfrom:
        fprintf(output, "No copyfrom information was written.\n");
    }
    else
        if (opt__is_verbose() > 0)
            fprintf(output, "%d copyfrom relation%s.\n", 
                    have, have == 1 ? "" : "s");

ex:
    if (db)
        STOPIF( hsh__close(db, status), NULL);

    return status;
}


int cm___make_copy(struct estat *root, 
        char *cp_src, svn_revnum_t revision,
        char *cp_dest, 
        int paths_are_wc_relative)
{
    int status;
    static const char err[]="!The %s path \"%s\" is not below the wc base.";
    struct estat *src, *dest;
    static hash_t db=NULL;
    char *abs_src, *abs_dest;
    char *wc_src, *wc_dest;
    char *buffer, *url;


    if (!root)
    {
        STOPIF( hsh__close(db, 0), NULL);
        goto ex;
    }

    /* That we shuffle the characters back and forth can be excused because
     * - either we are cmdline triggered, in which case we have the full task 
     *   starting overhead, and don't do it here again, and
     * - if we're doing a list of entries, we have to do it at least here. */

    if (paths_are_wc_relative)
    {
        wc_dest=cp_dest;
        wc_src=cp_src;
    }
    else
    {
        STOPIF( cm___absolute_path(cp_dest, &abs_dest), NULL);
        STOPIF( cm___absolute_path(cp_src, &abs_src), NULL);

        STOPIF( cm___not_below_wcpath(abs_dest, &wc_dest),
                err, "destination", abs_dest);
        STOPIF( cm___not_below_wcpath(abs_src, &wc_src),
                err, "source", abs_src);
    }


    STOPIF( ops__traverse(root, cp_src, 0, 0, &src), NULL);

    /* TODO: Make copying copied entries possible.
     * But as we only know the URL, we'd either have to do a checkout, or try 
     * to parse back to the original entry. */
    STOPIF_CODE_ERR( src->flags & RF___IS_COPY, EINVAL,
            "!Copied entries must be committed before using them as copyfrom source.");

    /* The directories above must be added; the entries below get RF_COPY_SUB 
     * set (by waa__copy_entries), and this entry gets overridden to 
     * RF_COPY_BASE below.  */
    STOPIF( ops__traverse(root, cp_dest, 
                OPS__CREATE, RF_ADD, 
                &dest), NULL);

    STOPIF_CODE_ERR( !(dest->flags & RF_ISNEW), EINVAL,
            "!The destination is already known - must be a new entry.");

    if (!db)
        STOPIF( hsh__new(wc_path, WAA__COPYFROM_EXT, GDBM_WRCREAT, &db), NULL);

    if (revision)
    {
        BUG_ON(1, "fetch list of entries from the repository");
    }
    else
    {
        STOPIF( waa__copy_entries(src, dest), NULL);
        revision=src->url->current_rev;
    }

    /* Mark as base entry for copy; the RF_ADD flag was removed by 
     * copy_entries above, but the entry really is *new*. */
    dest->flags |= RF_COPY_BASE;
    dest->flags &= ~RF_COPY_SUB;


    STOPIF( url__full_url( src, &url), NULL);
    STOPIF( cm___rev_path_to_string(url, revision, &buffer), NULL);
    STOPIF( hsh__store_charp(db, wc_dest, buffer), NULL);

ex:
    return status;
}


int cm___ignore_impl_copied(struct estat *cur)
{
    struct estat **sts;
    int all_ign;


    all_ign=1;
    cur->flags &= ~RF_COPY_SUB;

    if (cur->flags & (RF_ADD | RF_PUSHPROPS))
        all_ign=0;

    if (ops__has_children(cur))
    {
        sts=cur->by_inode;
        while (*sts)
        {
            all_ign &= cm___ignore_impl_copied(*sts);
            sts++;
        }
    }

    if (all_ign)
        cur->to_be_ignored=1;
    else
        /* We need that because of its children, and we have to check. */
        cur->flags |= RF_ADD | RF_CHECK;
    DEBUGP("%s: all_ignore=%d", cur->name, all_ign);

    return all_ign;
}


int cm__uncopy(struct estat *root, int argc, char *argv[])
{
    int status;
    char **normalized;
    struct estat *dest;


    /* Do only the selected elements. */
    opt_recursive=-1;

    if (!argc)
        ac__Usage_this();

    STOPIF( waa__find_common_base(argc, argv, &normalized), NULL);

    STOPIF( url__load_nonempty_list(NULL, 0), NULL);


    /* Load the current data, without updating */
    status=waa__input_tree(root, NULL, NULL);
    if (status == ENOENT)
        STOPIF( EINVAL, "!No working copy could be found.");
    else
        STOPIF( status, NULL);

    while (*normalized)
    {
        DEBUGP("uncopy %s %s", *normalized, normalized[1]);

        STOPIF( ops__traverse(root, *normalized, 
                    OPS__FAIL_NOT_LIST, 0, 
                    &dest), 
                "!The entry \"%s\" is not known.", *normalized);
        STOPIF_CODE_ERR( !(dest->flags & RF_COPY_BASE), EINVAL,
                "!The entry \"%s\" is not a copy base.", *normalized);

        /* Directly copied, unchanged entry.
         * Make it unknown - remove copy relation (ie. mark hash value for 
         * deletion), and remove entry from local list. */
        STOPIF( cm__get_source(dest, NULL, NULL, NULL, 1), NULL);

        dest->flags &= ~RF_COPY_BASE;

        /* That removes all not explicitly added entries from this subtree. */
        cm___ignore_impl_copied(dest);

        normalized++;
    }

    STOPIF( waa__output_tree(root), NULL);
    /* Purge. */
    STOPIF( cm__get_source(NULL, NULL, NULL, NULL, 0), NULL);

ex:
    return status;
}


int cm__work(struct estat *root, int argc, char *argv[])
{
    int status;
    char **normalized;
    int count;
    FILE *input=stdin;
    char *src, *dest, *cp;
    int is_dump, is_load;
    svn_revnum_t revision;


    status=0;
    is_load=is_dump=0;

    /* We have to do the parameter checking in two halfs, because we must not 
     * use "dump" or "load" as working copy path. So we first check what to do, 
     * eventually remove these strings from the parameters, and then look for 
     * the wc base. */
    /* If there's \b no parameter given, we default to dump. */
    if (argc==0) 
        is_dump=1;
    else if (strcmp(argv[0], parm_dump) == 0)
    {
        is_dump=1;
        argv++;
        argc--;
    }
    else if (strcmp(argv[0], parm_load) == 0)
    {
        is_load=1;
        argv++;
        argc--;
    }

    STOPIF( waa__find_common_base(argc, argv, &normalized), NULL);

    if (is_dump)
    {
        STOPIF( cm___dump_list(stdout, argc, normalized), NULL);
        /* To avoid the indentation */
        goto ex;
    }


    switch (opt_target_revisions_given)
    {
        case 0:
            /* Default is \c BASE. */
            revision=0;
            break;
        case 1:
            revision=opt_target_revision;
        default:
            STOPIF( EINVAL, "!Only a single revision number may be given.");
    }


    STOPIF( url__load_nonempty_list(NULL, 0), NULL);

    /* Load the current data, without updating; so st.mode equals 
     * st.local_mode_packed and so on. */
    status=waa__input_tree(root, NULL, NULL);
    if (status == -ENOENT)
        STOPIF(status, "!No entries are currently known, "
                "so you can't define copy or move relations yet.\n");
    STOPIF(status, NULL);

    hlp__string_from_filep(NULL, NULL, NULL, SFF_RESET_LINENUM);

    if (is_load)
    {
        /* Load copyfrom data. */
        count=0;

        while (1)
        {
            status=hlp__string_from_filep(input, &cp, NULL, 0);
            if (status == EOF) 
            {
                status=0;
                break;
            }
            STOPIF( status, "Failed to read copyfrom source");

            STOPIF_CODE_ERR( !*cp, EINVAL, 
                    "!Copyfrom source must not be empty.");
            STOPIF( hlp__strdup( &src, cp), NULL);


            status=hlp__string_from_filep(input, &cp, NULL, 0);
            STOPIF_CODE_ERR( status == EOF, EINVAL,
                    "!Expected a target specification, got EOF!");
            STOPIF( status, "Failed to read copyfrom destination");

            STOPIF( hlp__strdup( &dest, cp), NULL);


            /* Get the empty line */
            status=hlp__string_from_filep(input, &cp, NULL, SFF_WHITESPACE);
            if (status == EOF)
                DEBUGP("delimiter line missing - EOF");
            else if (status == 0 && 
                    cp[0] == '.' && cp[1] == 0)
                DEBUGP("delimiter line ok");
            else
            {
                STOPIF(status, "Cannot read delimiter line");
                /* status == 0 ? not empty. */
                STOPIF(EINVAL, "Expected delimiter line - got %s", cp);
            }

            DEBUGP("read %s => %s", src, dest);
            /* These paths were given relative to the cwd, which is changed now, as 
             * we're in the wc base. Calculate correct names. */

            STOPIF( cm___make_copy(root, src, revision, dest, 0), NULL);
            count++;

            free(dest);
            free(src);
        }

        if (opt__is_verbose() >= 0)
            printf("%d copyfrom relation%s loaded.\n", count, count==1 ? "" : "s");
    }
    else
    {
        STOPIF_CODE_ERR(argc != 2, EINVAL, 
                "!At least source and destination, "
                "or \"dump\" resp. \"load\" must be given.");

        /* Create database file for WC root. */
        STOPIF( cm___make_copy(root, 
                    normalized[0], revision, 
                    normalized[1], 1), 
                "Storing \"%s\" as source of \"%s\" failed.",
                normalized[0], normalized[1]);
    }

    STOPIF( cm___make_copy(NULL, NULL, 0, NULL, 0), NULL);
    STOPIF( waa__output_tree(root), NULL);

ex:
    return status;
}



int cm___get_base_source(struct estat *sts, char *name,
        char **src_url, svn_revnum_t *src_rev,
        int alloc_extra,
        int register_for_cleanup)
{
    int status;
    datum key, value;
    static hash_t hash;
    static int init=0;
    char *url;


    value.dptr=NULL;
    status=0;
    if (src_url) *src_url=NULL;
    if (src_rev) *src_rev=SVN_INVALID_REVNUM;

    if (!sts)
    {
        /* uninit */
        STOPIF( hsh__close(hash, register_for_cleanup), NULL);
        hash=NULL;
        init=0;
        goto ex;
    }

    if (!init)
    {
        /* We cannot simply use !hash as condition; if there is no database with 
         * copyfrom information, we'd try to open it *every* time we're asked for 
         * a source, which is clearly not optimal for performance.
         * So we use an static integer. */
        init=1;

        /* In case there's a cleanup at the end we have to open read/write. */
        status=hsh__new(wc_path, WAA__COPYFROM_EXT, 
                GDBM_WRITER | HASH_REMEMBER_FILENAME, &hash);
        /* If we got an ENOENT here, hash==NULL; so we'll re-set the 
         * *parameters below and return. */
        if (status != ENOENT)
            STOPIF( status, NULL);
    }

    /* Normal proceedings, this is a direct target of a copy definition. */
    if (!name)
        STOPIF( ops__build_path( &name, sts), NULL);

    if (name[0]=='.' && name[1]==PATH_SEPARATOR)
        name+=2;

    key.dptr=name;
    key.dsize=strlen(name)+1;
    status=hsh__fetch(hash, key, &value);
    if (status) 
    {
        DEBUGP("no source for %s found",
                name);
        goto ex;
    }

    if (register_for_cleanup)
        STOPIF( hsh__register_delete(hash, key), NULL);

    /* Extract the revision number. */
    STOPIF( cm___string_to_rev_path( value.dptr, 
                &url, src_rev), NULL);

    if (src_url)
    {
        BUG_ON(!url);

        status=strlen(url);
        /* In case the caller wants to do something with this buffer, we return 
         * more. We need at least the additional \0; and we give a few byte 
         * extra, gratis, free for nothing (and that's cutting my own throat)!  
         * */
        STOPIF( hlp__strnalloc( status + 1 +alloc_extra + 4, 
                    src_url, url), NULL);
        status=0;
    }

ex:
    IF_FREE(value.dptr);
    return status;
}


int cm___get_sub_source_rek(struct estat *cur, int length_to_add,
        char **dest_buffer, svn_revnum_t *src_rev,
        char **eobuffer)
{
    int status;
    struct estat *copied;
    int len;


    /* Get source of parent.
     * Just because this entry should be removed from the copyfrom database 
     * that isn't automatically true for the corresponding parent. */
    copied=cur->parent;
    BUG_ON(!copied, "Copy-sub but no base?");
    len=strlen(cur->name);

    length_to_add+=len+1;

    if (copied->flags & RF_COPY_BASE)
    {
        /* Silent error return. */
        status=cm___get_base_source(copied, NULL, 
                dest_buffer, src_rev, 
                length_to_add, 0);
        if (status) goto ex;

        *eobuffer=*dest_buffer+strlen(*dest_buffer);
        DEBUGP("after base eob-5=%s", *eobuffer-5);
    }
    else
    {
        /* Maybe better do (sts->path_len - copied->path_len))?
         * Would be faster. */
        status=cm___get_sub_source_rek(copied, length_to_add,
                dest_buffer, src_rev, eobuffer);
        if (status) goto ex;
    }

    /* Now we have the parent's URL ... put cur->name after it. */
    /* Not PATH_SEPARATOR, it's an URL and not a pathname. */
    **eobuffer = '/';
    strcpy( *eobuffer +1, cur->name );
    *eobuffer += len+1;

    DEBUGP("sub source of %s is %s", cur->name, *dest_buffer);

ex:
    return status;
}


int cm___get_sub_source(struct estat *sts, char *name,
        char **src_url, svn_revnum_t *src_rev)
{
    int status;
    char *eob;


    /* As we only store the URL in the hash database, we have to proceed as 
     * follows:
     * - Look which parent is the copy source,
     * - Get its URL
     * - Append the path after that to the URL of the copy source:
     *     root / dir1 / dir2 / <copied_dest> / dir3 / <sts>
     *   and
     *     root / dir1 / dir3 / <src>
     * Disadvantage: 
     * - we have to traverse the entries, and make the estat::by_name 
     *   arrays for all intermediate nodes.
     *
     * We do that as a recursive sub-function, to make bookkeeping easier. */
    STOPIF( cm___get_sub_source_rek(sts, 0, src_url, src_rev, &eob), NULL);

ex:
    return status;
}


int cm__get_source(struct estat *sts, char *name,
        char **src_url, svn_revnum_t *src_rev,
        int register_for_cleanup)
{
    int status;


    if (!sts)
    {
        status=cm___get_base_source(NULL, NULL, NULL, NULL, 0, 0);
        goto ex;
    }

    if (sts->flags & RF_COPY_BASE)
    {
        status= cm___get_base_source(sts, name, 
                src_url, src_rev, 0,
                register_for_cleanup);
    }
    else if (sts->flags & RF_COPY_SUB)
    {
        status= cm___get_sub_source(sts, name, 
                src_url, src_rev);
    }
    else
    {
        status=ENOENT;
        goto ex;
    }

    if (src_url)
        DEBUGP("source of %s is %s", sts->name, *src_url);

    if (status)
    {
        /* That's a bug ... the bit is set, but no source was found?
         * Could some stale entry cause that? Don't error out now; perhaps at a 
         * later time. */
        DEBUGP("bit set, no source!");
        /* BUG_ON(1,"bit set, no source!"); */
        goto ex;
    }

ex:
    return status;
}

---