#include "poll-loop.h"
#include "shash.h"
#include "util.h"
-
-#define THIS_MODULE VLM_ovsdb_idl
#include "vlog.h"
+VLOG_DEFINE_THIS_MODULE(ovsdb_idl)
+
/* An arc from one idl_row to another. When row A contains a UUID that
* references row B, this is represented by an arc from A (the source) to B
* (the destination).
static bool ovsdb_idl_txn_process_reply(struct ovsdb_idl *,
const struct jsonrpc_msg *msg);
+/* Creates and returns a connection to database 'remote', which should be in a
+ * form acceptable to jsonrpc_session_open(). The connection will maintain an
+ * in-memory replica of the remote database whose schema is described by
+ * 'class'. (Ordinarily 'class' is compiled from an OVSDB schema automatically
+ * by ovsdb-idlc.) */
struct ovsdb_idl *
ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class)
{
struct ovsdb_idl_table *table = &idl->tables[i];
size_t j;
- assert(!shash_find(&idl->table_by_name, tc->name));
- shash_add(&idl->table_by_name, tc->name, table);
+ shash_add_assert(&idl->table_by_name, tc->name, table);
table->class = tc;
shash_init(&table->columns);
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
- assert(!shash_find(&table->columns, column->name));
- shash_add(&table->columns, column->name, column);
+ shash_add_assert(&table->columns, column->name, column);
}
hmap_init(&table->rows);
table->idl = idl;
return idl;
}
+/* Destroys 'idl' and all of the data structures that it manages. */
void
ovsdb_idl_destroy(struct ovsdb_idl *idl)
{
}
}
-void
+/* Processes a batch of messages from the database server on 'idl'. Returns
+ * true if the database as seen through 'idl' changed, false if it did not
+ * change. The initial fetch of the entire contents of the remote database is
+ * considered to be one kind of change.
+ *
+ * When this function returns false, the client may continue to use any data
+ * structures it obtained from 'idl' in the past. But when it returns true,
+ * the client must not access any of these data structures again, because they
+ * could have freed or reused for other purposes.
+ *
+ * This function can return occasional false positives, that is, report that
+ * the database changed even though it didn't. This happens if the connection
+ * to the database drops and reconnects, which causes the database contents to
+ * be reloaded even if they didn't change. (It could also happen if the
+ * database server sends out a "change" that reflects what we already thought
+ * was in the database, but the database server is not supposed to do that.)
+ *
+ * As an alternative to checking the return value, the client may check for
+ * changes in the value returned by ovsdb_idl_get_seqno().
+ */
+bool
ovsdb_idl_run(struct ovsdb_idl *idl)
{
+ unsigned int initial_change_seqno = idl->change_seqno;
int i;
assert(!idl->txn);
}
jsonrpc_msg_destroy(msg);
}
+
+ return initial_change_seqno != idl->change_seqno;
}
+/* Arranges for poll_block() to wake up when ovsdb_idl_run() has something to
+ * do or when activity occurs on a transaction on 'idl'. */
void
ovsdb_idl_wait(struct ovsdb_idl *idl)
{
jsonrpc_session_recv_wait(idl->session);
}
+/* Returns a number that represents the state of 'idl'. When 'idl' is updated
+ * (by ovsdb_idl_run()), the return value changes. */
unsigned int
ovsdb_idl_get_seqno(const struct ovsdb_idl *idl)
{
return idl->change_seqno;
}
+/* Returns true if 'idl' successfully connected to the remote database and
+ * retrieved its contents (even if the connection subsequently dropped and is
+ * in the process of reconnecting). If so, then 'idl' contains an atomic
+ * snapshot of the database's contents (but it might be arbitrarily old if the
+ * connection dropped).
+ *
+ * Returns false if 'idl' has never connected or retrieved the database's
+ * contents. If so, 'idl' is empty. */
bool
ovsdb_idl_has_ever_connected(const struct ovsdb_idl *idl)
{
return ovsdb_idl_get_seqno(idl) != 0;
}
+/* Forces 'idl' to drop its connection to the database and reconnect. In the
+ * meantime, the contents of 'idl' will not change. */
void
ovsdb_idl_force_reconnect(struct ovsdb_idl *idl)
{
const struct ovsdb_idl_table_class *class = row->table->class;
size_t i;
- BITMAP_FOR_EACH_1 (i, class->n_columns, row->written) {
- ovsdb_datum_destroy(&row->new[i], &class->columns[i].type);
+ if (row->written) {
+ BITMAP_FOR_EACH_1 (i, class->n_columns, row->written) {
+ ovsdb_datum_destroy(&row->new[i], &class->columns[i].type);
+ }
}
free(row->new);
free(row->written);
return next_real_row(table, hmap_next(&table->rows, &row->hmap_node));
}
+
+/* Reads and returns the value of 'column' within 'row'. If an ongoing
+ * transaction has changed 'column''s value, the modified value is returned.
+ *
+ * The caller must not modify or free the returned value.
+ *
+ * Various kinds of changes can invalidate the returned value: writing to the
+ * same 'column' in 'row' (e.g. with ovsdb_idl_txn_write()), deleting 'row'
+ * (e.g. with ovsdb_idl_txn_delete()), or completing an ongoing transaction
+ * (e.g. with ovsdb_idl_txn_commit() or ovsdb_idl_txn_abort()). If the
+ * returned value is needed for a long time, it is best to make a copy of it
+ * with ovsdb_datum_clone(). */
+const struct ovsdb_datum *
+ovsdb_idl_read(const struct ovsdb_idl_row *row,
+ const struct ovsdb_idl_column *column)
+{
+ const struct ovsdb_idl_table_class *class = row->table->class;
+ size_t column_idx = column - class->columns;
+
+ assert(row->new != NULL);
+ assert(column_idx < class->n_columns);
+
+ if (row->written && bitmap_is_set(row->written, column_idx)) {
+ return &row->new[column_idx];
+ } else if (row->old) {
+ return &row->old[column_idx];
+ } else {
+ return ovsdb_datum_default(&column->type);
+ }
+}
+
+/* Same as ovsdb_idl_read(), except that it also asserts that 'column' has key
+ * type 'key_type' and value type 'value_type'. (Scalar and set types will
+ * have a value type of OVSDB_TYPE_VOID.)
+ *
+ * This is useful in code that "knows" that a particular column has a given
+ * type, so that it will abort if someone changes the column's type without
+ * updating the code that uses it. */
+const struct ovsdb_datum *
+ovsdb_idl_get(const struct ovsdb_idl_row *row,
+ const struct ovsdb_idl_column *column,
+ enum ovsdb_atomic_type key_type OVS_UNUSED,
+ enum ovsdb_atomic_type value_type OVS_UNUSED)
+{
+ assert(column->type.key.type == key_type);
+ assert(column->type.value.type == value_type);
+
+ return ovsdb_idl_read(row, column);
+}
\f
/* Transactions. */
row_json = json_object_create();
json_object_put(op, "row", row_json);
- BITMAP_FOR_EACH_1 (idx, class->n_columns, row->written) {
- const struct ovsdb_idl_column *column = &class->columns[idx];
-
- if (row->old
- ? !ovsdb_datum_equals(&row->old[idx], &row->new[idx],
- &column->type)
- : !ovsdb_datum_is_default(&row->new[idx], &column->type)) {
- json_object_put(row_json, column->name,
- substitute_uuids(
- ovsdb_datum_to_json(&row->new[idx],
- &column->type),
- txn));
+ if (row->written) {
+ BITMAP_FOR_EACH_1 (idx, class->n_columns, row->written) {
+ const struct ovsdb_idl_column *column =
+ &class->columns[idx];
+
+ if (row->old
+ ? !ovsdb_datum_equals(&row->old[idx], &row->new[idx],
+ &column->type)
+ : !ovsdb_datum_is_default(&row->new[idx],
+ &column->type)) {
+ json_object_put(row_json, column->name,
+ substitute_uuids(
+ ovsdb_datum_to_json(&row->new[idx],
+ &column->type),
+ txn));
+ }
}
}
hmap_remove(&txn->idl->outstanding_txns, &txn->hmap_node);
}
-void
-ovsdb_idl_txn_read(const struct ovsdb_idl_row *row,
- const struct ovsdb_idl_column *column,
- struct ovsdb_datum *datum)
-{
- const struct ovsdb_idl_table_class *class = row->table->class;
- size_t column_idx = column - class->columns;
-
- assert(row->new != NULL);
- if (row->written && bitmap_is_set(row->written, column_idx)) {
- ovsdb_datum_clone(datum, &row->new[column_idx], &column->type);
- } else if (row->old) {
- ovsdb_datum_clone(datum, &row->old[column_idx], &column->type);
- } else {
- ovsdb_datum_init_default(datum, &column->type);
- }
-}
-
void
ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_,
const struct ovsdb_idl_column *column,
const struct ovsdb_idl_row *
ovsdb_idl_txn_insert(struct ovsdb_idl_txn *txn,
- const struct ovsdb_idl_table_class *class)
+ const struct ovsdb_idl_table_class *class,
+ const struct uuid *uuid)
{
struct ovsdb_idl_row *row = ovsdb_idl_row_create__(class);
- uuid_generate(&row->uuid);
+
+ if (uuid) {
+ assert(!ovsdb_idl_txn_get_row(txn, uuid));
+ row->uuid = *uuid;
+ } else {
+ uuid_generate(&row->uuid);
+ }
+
row->table = ovsdb_idl_table_from_class(txn->idl, class);
row->new = xmalloc(class->n_columns * sizeof *row->new);
- row->written = bitmap_allocate(class->n_columns);
hmap_insert(&row->table->rows, &row->hmap_node, uuid_hash(&row->uuid));
hmap_insert(&txn->txn_rows, &row->txn_node, uuid_hash(&row->uuid));
return row;