[ovs-dev] [ovsdb-idlc 3/4] ovsdb-idlc: Add comments for remaining non-static functions.
Justin Pettit
jpettit at nicira.com
Wed Mar 4 19:25:52 UTC 2015
Signed-off-by: Justin Pettit <jpettit at nicira.com>
---
ovsdb/ovsdb-idlc.in | 76 +++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 64 insertions(+), 12 deletions(-)
diff --git a/ovsdb/ovsdb-idlc.in b/ovsdb/ovsdb-idlc.in
index fa78736..7ac332e 100755
--- a/ovsdb/ovsdb-idlc.in
+++ b/ovsdb/ovsdb-idlc.in
@@ -409,10 +409,11 @@ static void
# Row Initialization function.
print """
+/* Clears the contents of 'row' in table "%(t)s". */
void
%(s)s_init(struct %(s)s *row)
{
- memset(row, 0, sizeof *row); """ % {'s': structName}
+ memset(row, 0, sizeof *row); """ % {'s': structName, 't': tableName}
for columnName, column in sorted(table.columns.iteritems()):
if column.type.is_smap():
print " smap_init(&row->%s);" % columnName
@@ -420,18 +421,28 @@ void
# First, next functions.
print '''
+/* Searches table "%(t)s" in 'idl' for a row with UUID 'uuid'. Returns
+ * a pointer to the row if there is one, otherwise a null pointer. */
const struct %(s)s *
%(s)s_get_for_uuid(const struct ovsdb_idl *idl, const struct uuid *uuid)
{
return %(s)s_cast(ovsdb_idl_get_row_for_uuid(idl, &%(p)stable_classes[%(P)sTABLE_%(T)s], uuid));
}
+/* Returns a row in table "%(t)s" in 'idl', or a null pointer if that
+ * table is empty.
+ *
+ * Database tables are internally maintained as hash tables, so adding or
+ * removing rows while traversing the same table can cause some rows to be
+ * visited twice or not at apply. */
const struct %(s)s *
%(s)s_first(const struct ovsdb_idl *idl)
{
return %(s)s_cast(ovsdb_idl_first_row(idl, &%(p)stable_classes[%(P)sTABLE_%(T)s]));
}
+/* Returns a row following 'row' within its table, or a null pointer if 'row'
+ * is the last row in its table. */
const struct %(s)s *
%(s)s_next(const struct %(s)s *row)
{
@@ -439,28 +450,65 @@ const struct %(s)s *
}''' % {'s': structName,
'p': prefix,
'P': prefix.upper(),
+ 't': tableName,
'T': tableName.upper()}
print '''
+/* Deletes 'row' from table "%(t)s". 'row' may be freed, so it must not be
+ * accessed afterward.
+ *
+ * A transaction must be in progress. */
void
%(s)s_delete(const struct %(s)s *row)
{
ovsdb_idl_txn_delete(&row->header_);
}
+/* Inserts and returns a new row in the table "%(t)s" in the database
+ * with open transaction 'txn'.
+ *
+ * The new row is assigned a randomly generate provisional UUID.
+ * ovsdb-server will assign a different UUID when 'txn' is committed,
+ * but the IDL will replace any uses of the provisional UUID in the
+ * data to be to be committed by the UUID assigned by ovsdb-server. */
struct %(s)s *
%(s)s_insert(struct ovsdb_idl_txn *txn)
{
return %(s)s_cast(ovsdb_idl_txn_insert(txn, &%(p)stable_classes[%(P)sTABLE_%(T)s], NULL));
-}
-''' % {'s': structName,
- 'p': prefix,
- 'P': prefix.upper(),
- 'T': tableName.upper()}
+}''' % {'s': structName,
+ 'p': prefix,
+ 'P': prefix.upper(),
+ 't': tableName,
+ 'T': tableName.upper()}
# Verify functions.
for columnName, column in sorted(table.columns.iteritems()):
print '''
+/* Causes the original contents of column "%(c)s" in 'row' to be
+ * verified as a prerequisite to completing the transaction. That is, if
+ * "%(c)s" in 'row' changed (or if 'row' was deleted) between the
+ * time that the IDL originally read its contents and the time that the
+ * transaction commits, then the transaction aborts and ovsdb_idl_txn_commit()
+ * returns TXN_AGAIN_WAIT or TXN_AGAIN_NOW (depending on whether the database
+ * change has already been received).
+ *
+ * The intention is that, to ensure that no transaction commits based on dirty
+ * reads, an application should call this function any time "%(c)s" is
+ * read as part of a read-modify-write operation.
+ *
+ * In some cases this function reduces to a no-op, because the current value
+ * of "%(c)s" is already known:
+ *
+ * - If 'row' is a row created by the current transaction (returned by
+ * %(s)s_insert()).
+ *
+ * - If "%(c)s" has already been modified (with
+ * %(s)s_set_%(c)s()) within the current transaction.
+ *
+ * Because of the latter property, always call this function *before*
+ * %(s)s_set_%(c)s() for a given read-modify-write.
+ *
+ * A transaction must be in progress. */
void
%(s)s_verify_%(c)s(const struct %(s)s *row)
{
@@ -482,10 +530,11 @@ void
valueType = ''
valueComment = ''
print """
-/* Returns the %(c)s column's value in 'row' as a struct ovsdb_datum.
- * This is useful occasionally: for example, ovsdb_datum_find_key() is an
- * easier and more efficient way to search for a given key than implementing
- * the same operation on the "cooked" form in 'row'.
+/* Returns the "%(c)s" column's value from the "%(t)s" table in 'row'
+ * as a struct ovsdb_datum. This is useful occasionally: for example,
+ * ovsdb_datum_find_key() is an easier and more efficient way to search
+ * for a given key than implementing the same operation on the "cooked"
+ * form in 'row'.
*
* 'key_type' must be %(kt)s.%(vc)s
* (This helps to avoid silent bugs if someone changes %(c)s's
@@ -496,14 +545,17 @@ void
* Various kinds of changes can invalidate the returned value: modifying
* 'column' within 'row', deleting 'row', or completing an ongoing transaction.
* If the returned value is needed for a long time, it is best to make a copy
- * of it with ovsdb_datum_clone(). */
+ * of it with ovsdb_datum_clone().
+ *
+ * This function is rarely useful, since it is easier to access the value
+ * directly through the "%(c)s" member in %(s)s. */
const struct ovsdb_datum *
%(s)s_get_%(c)s(const struct %(s)s *row,
\tenum ovsdb_atomic_type key_type OVS_UNUSED%(v)s)
{
ovs_assert(key_type == %(kt)s);%(vt)s
return ovsdb_idl_read(&row->header_, &%(s)s_col_%(c)s);
-}""" % {'s': structName, 'c': columnName,
+}""" % {'t': tableName, 's': structName, 'c': columnName,
'kt': column.type.key.toAtomicType(),
'v': valueParam, 'vt': valueType, 'vc': valueComment}
--
1.7.5.4
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