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; }
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; }