int SLNFilterCopyURI(SLNFilterRef const filter, uint64_t const fileID, bool const meta, DB_txn *const txn, str_t **const out) {
DB_val fileID_key[1], file_val[1];
SLNFileByIDKeyPack(fileID_key, txn, fileID);
int rc = db_get(txn, fileID_key, file_val);
if(rc < 0) return rc;
strarg_t const hash = db_read_string(file_val, txn);
db_assert(hash);
str_t *URI = NULL;
if(!meta) {
URI = SLNFormatURI(SLN_INTERNAL_ALGO, hash);
if(!URI) return DB_ENOMEM;
} else {
DB_val key[1], val[1];
SLNMetaFileByIDKeyPack(key, txn, fileID);
rc = db_get(txn, key, val);
if(rc < 0) return rc;
uint64_t f;
strarg_t target = NULL;
SLNMetaFileByIDValUnpack(val, txn, &f, &target);
db_assert(target);
URI = aasprintf("hash://%s/%s -> %s", SLN_INTERNAL_ALGO, hash, target);
if(!URI) return DB_ENOMEM;
}
*out = URI; URI = NULL;
return 0;
}
static uint64_t add_metafile(DB_txn *const txn, uint64_t const fileID, strarg_t const targetURI) {
uint64_t const metaFileID = fileID;
uint64_t const latestMetaFileID = db_next_id(SLNMetaFileByID, txn);
if(metaFileID < latestMetaFileID) return 0;
// If it's not a new file, then it's not a new meta-file.
// Note that ordinary files can't be "promoted" to meta-files later
// because that would break the ordering.
DB_val null = { 0, NULL };
DB_cursor *cursor = NULL;
int rc = db_txn_cursor(txn, &cursor);
assert(rc >= 0);
DB_val metaFileID_key[1];
SLNMetaFileByIDKeyPack(metaFileID_key, txn, metaFileID);
DB_val metaFile_val[1];
SLNMetaFileByIDValPack(metaFile_val, txn, fileID, targetURI);
rc = db_put(txn, metaFileID_key, metaFile_val, DB_NOOVERWRITE_FAST);
assert(rc >= 0);
DB_range alts[1];
SLNTargetURIAndMetaFileIDRange1(alts, txn, targetURI);
rc = db_cursor_firstr(cursor, alts, NULL, NULL, +1);
assert(rc >= 0 || DB_NOTFOUND == rc);
if(DB_NOTFOUND == rc) {
DB_val unique[1];
SLNFirstUniqueMetaFileIDKeyPack(unique, txn, metaFileID);
rc = db_put(txn, unique, &null, DB_NOOVERWRITE_FAST);
assert(rc >= 0);
}
DB_val targetURI_key[1];
SLNTargetURIAndMetaFileIDKeyPack(targetURI_key, txn, targetURI, metaFileID);
rc = db_put(txn, targetURI_key, &null, DB_NOOVERWRITE_FAST);
assert(rc >= 0);
return metaFileID;
}
