int SLNSessionGetValueForField(SLNSessionRef const session, str_t value[], size_t const max, strarg_t const fileURI, strarg_t const field) {
if(!SLNSessionHasPermission(session, SLN_RDONLY)) return DB_EACCES;
if(!field) return DB_EINVAL;
if(max) value[0] = '\0';
int rc = 0;
DB_cursor *metafiles = NULL;
DB_cursor *values = NULL;
SLNRepoRef const repo = SLNSessionGetRepo(session);
DB_env *db = NULL;
SLNRepoDBOpen(repo, &db);
DB_txn *txn = NULL;
rc = db_txn_begin(db, NULL, DB_RDONLY, &txn);
if(rc < 0) goto done;
rc = db_cursor_open(txn, &metafiles);
if(rc < 0) goto done;
rc = db_cursor_open(txn, &values);
if(rc < 0) goto done;
DB_range metaFileIDs[1];
SLNTargetURIAndMetaFileIDRange1(metaFileIDs, txn, fileURI);
DB_val metaFileID_key[1];
rc = db_cursor_firstr(metafiles, metaFileIDs, metaFileID_key, NULL, +1);
if(rc < 0 && DB_NOTFOUND != rc) goto done;
for(; rc >= 0; rc = db_cursor_nextr(metafiles, metaFileIDs, metaFileID_key, NULL, +1)) {
strarg_t u;
uint64_t metaFileID;
SLNTargetURIAndMetaFileIDKeyUnpack(metaFileID_key, txn, &u, &metaFileID);
assert(0 == strcmp(fileURI, u));
DB_range vrange[1];
SLNMetaFileIDFieldAndValueRange2(vrange, txn, metaFileID, field);
DB_val value_val[1];
rc = db_cursor_firstr(values, vrange, value_val, NULL, +1);
if(rc < 0 && DB_NOTFOUND != rc) goto done;
for(; rc >= 0; rc = db_cursor_nextr(values, vrange, value_val, NULL, +1)) {
uint64_t m;
strarg_t f, v;
SLNMetaFileIDFieldAndValueKeyUnpack(value_val, txn, &m, &f, &v);
assert(metaFileID == m);
assert(0 == strcmp(field, f));
if(!v) continue;
if(0 == strcmp("", v)) continue;
size_t const len = strlen(v);
memcpy(value, v, MIN(len, max-1));
value[MIN(len, max-1)] = '\0';
goto done;
}
}
done:
db_cursor_close(values); values = NULL;
db_cursor_close(metafiles); metafiles = NULL;
db_txn_abort(txn); txn = NULL;
SLNRepoDBClose(repo, &db);
return rc;
}
int SLNSessionGetValueForField(SLNSessionRef const session, DB_txn *const txn, strarg_t const fileURI, strarg_t const field, str_t *out, size_t const max) {
int rc = 0;
DB_cursor *metafiles = NULL;
DB_cursor *values = NULL;
rc = db_cursor_open(txn, &metafiles);
if(rc < 0) goto done;
rc = db_cursor_open(txn, &values);
if(rc < 0) goto done;
DB_range metaFileIDs[1];
SLNTargetURIAndMetaFileIDRange1(metaFileIDs, txn, fileURI);
DB_val metaFileID_key[1];
rc = db_cursor_firstr(metafiles, metaFileIDs, metaFileID_key, NULL, +1);
if(rc < 0 && DB_NOTFOUND != rc) goto done;
for(; rc >= 0; rc = db_cursor_nextr(metafiles, metaFileIDs, metaFileID_key, NULL, +1)) {
strarg_t u;
uint64_t metaFileID;
SLNTargetURIAndMetaFileIDKeyUnpack(metaFileID_key, txn, &u, &metaFileID);
assert(0 == strcmp(fileURI, u));
DB_range vrange[1];
SLNMetaFileIDFieldAndValueRange2(vrange, txn, metaFileID, field);
DB_val value_val[1];
rc = db_cursor_firstr(values, vrange, value_val, NULL, +1);
if(rc < 0 && DB_NOTFOUND != rc) goto done;
for(; rc >= 0; rc = db_cursor_nextr(values, vrange, value_val, NULL, +1)) {
uint64_t m;
strarg_t f, v;
SLNMetaFileIDFieldAndValueKeyUnpack(value_val, txn, &m, &f, &v);
assert(metaFileID == m);
assert(0 == strcmp(field, f));
if(!v || '\0' == v[0]) continue;
strlcpy(out, v, max);
goto done;
}
}
done:
db_cursor_close(values); values = NULL;
db_cursor_close(metafiles); metafiles = NULL;
return rc;
}
