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;
}
int SLNFilterSeekToPosition(SLNFilterRef const filter, SLNFilterPosition const *const pos, DB_txn *const txn) {
if(!pos->URI) {
SLNFilterSeek(filter, pos->dir, pos->sortID, pos->fileID);
if(valid(pos->fileID)) SLNFilterStep(filter, pos->dir);
return 0;
}
DB_cursor *cursor = NULL;
int rc = db_txn_cursor(txn, &cursor);
if(rc < 0) return rc;
DB_range range[1];
DB_val key[1];
SLNURIAndFileIDRange1(range, txn, pos->URI);
rc = db_cursor_firstr(cursor, range, key, NULL, +1);
if(rc < 0) return rc;
// Test that this URI gives us a unique, unambiguous position.
// This is guaranteed for the internal hash and effectively
// guaranteed for other cryptographic hashes, but may not be
// true for other hash algorithms.
rc = db_cursor_nextr(cursor, range, NULL, NULL, +1);
if(rc >= 0) return DB_KEYEXIST;
if(DB_NOTFOUND != rc) return rc;
strarg_t u;
uint64_t fileID;
SLNURIAndFileIDKeyUnpack(key, txn, &u, &fileID);
assert(0 == strcmp(pos->URI, u));
SLNAgeRange const ages = SLNFilterFullAge(filter, fileID);
if(!valid(ages.min) || ages.min > ages.max) return DB_NOTFOUND;
uint64_t const sortID = ages.min;
SLNFilterSeek(filter, pos->dir, sortID, fileID);
SLNFilterStep(filter, pos->dir); // Start just before/after the URI.
// TODO: Stepping is almost assuredly wrong if the URI doesn't match
// the filter. We should check if our seek was a direct hit, and
// only step if it was.
return 0;
}
int SLNSessionGetSubmittedFile(SLNSessionRef const session, DB_txn *const txn, strarg_t const URI) {
uint64_t const sessionID = SLNSessionGetID(session);
DB_cursor *cursor = NULL;
int rc = db_txn_cursor(txn, &cursor);
if(rc < 0) return rc;
DB_range range[1];
DB_val filekey[1];
SLNURIAndFileIDRange1(range, txn, URI);
rc = db_cursor_firstr(cursor, range, filekey, NULL, +1);
if(rc < 0) return rc;
for(; rc >= 0; rc = db_cursor_nextr(cursor, range, filekey, NULL, +1)) {
strarg_t u;
uint64_t fileID;
SLNURIAndFileIDKeyUnpack(filekey, txn, &u, &fileID);
DB_val sessionkey[1];
SLNFileIDAndSessionIDKeyPack(sessionkey, txn, fileID, sessionID);
rc = db_cursor_seek(cursor, sessionkey, NULL, 0);
if(DB_NOTFOUND == rc) continue;
return rc;
}
return SLN_NOSESSION;
}
