The conditional replication code had hardly any comments. This adds some.
This commit also fixes a number of style problems, factors out some code
into a helper function, and moves some struct declarations from a public
header, that were not used by client code, into more private locations.
Signed-off-by: Ben Pfaff <b...@ovn.org>
---
lib/ovsdb-idl-provider.h | 7 ++-
lib/ovsdb-idl.c | 112 ++++++++++++++++++++++++++++++++---------------
lib/ovsdb-idl.h | 26 +++++------
3 files changed, 94 insertions(+), 51 deletions(-)
diff --git a/lib/ovsdb-idl-provider.h b/lib/ovsdb-idl-provider.h
index 55ed793..e0221d0 100644
--- a/lib/ovsdb-idl-provider.h
+++ b/lib/ovsdb-idl-provider.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2011, 2012, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -63,6 +63,11 @@ struct ovsdb_idl_table_class {
void (*row_init)(struct ovsdb_idl_row *);
};
+struct ovsdb_idl_condition {
+ const struct ovsdb_idl_table_class *tc;
+ struct ovs_list clauses;
+};
+
struct ovsdb_idl_table {
const struct ovsdb_idl_table_class *class;
unsigned char *modes; /* OVSDB_IDL_* bitmasks, indexed by column. */
diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c
index 7da25a5..df4193b 100644
--- a/lib/ovsdb-idl.c
+++ b/lib/ovsdb-idl.c
@@ -710,6 +710,13 @@ ovsdb_idl_add_table(struct ovsdb_idl *idl,
OVS_NOT_REACHED();
}
+
+struct ovsdb_idl_clause {
+ struct ovs_list node;
+ enum ovsdb_function function;
+ const struct ovsdb_idl_column *column;
+ struct ovsdb_datum arg;
+};
static struct json *
ovsdb_idl_clause_to_json(const struct ovsdb_idl_clause *clause)
@@ -740,6 +747,10 @@ ovsdb_idl_clause_free(struct ovsdb_idl_clause *clause)
free(clause);
}
+/* Clears all of the conditional clauses from table 'tc', so that all of the
+ * rows in the table will be replicated. (This is the default, so this
+ * function has an effect only if some clauses were added to 'tc' using
+ * ovsdb_idl_condition_add_clause().) */
void
ovsdb_idl_condition_reset(struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc)
@@ -761,59 +772,90 @@ ovsdb_idl_condition_init(struct ovsdb_idl_condition *cnd,
ovs_list_init(&cnd->clauses);
}
-void ovsdb_idl_condition_add_clause(struct ovsdb_idl *idl,
- const struct ovsdb_idl_table_class *tc,
- enum ovsdb_function function,
- const struct ovsdb_idl_column *column,
- struct ovsdb_datum *arg)
+static struct ovsdb_idl_clause *
+ovsdb_idl_condition_find_clause(struct ovsdb_idl_table *table,
+ enum ovsdb_function function,
+ const struct ovsdb_idl_column *column,
+ const struct ovsdb_datum *arg)
{
- struct ovsdb_idl_table *table = ovsdb_idl_table_from_class(idl, tc);
- const struct ovsdb_type *type = NULL;
struct ovsdb_idl_clause *c;
-
- LIST_FOR_EACH(c, node, &table->condition.clauses) {
+ LIST_FOR_EACH (c, node, &table->condition.clauses) {
if (c->function == function &&
(!column || (c->column == column &&
ovsdb_datum_equals(&c->arg,
arg, &column->type)))) {
- return;
+ return c;
}
}
+ return NULL;
+}
+
+/* Adds a clause to the condition for replicating the table with class 'tc' in
+ * 'idl'.
+ *
+ * By default, a table has no clauses, and in that case the IDL replicates all
+ * its rows. When a table has one or more clauses, the IDL replicates only
+ * rows that satisfy at least one clause.
+ *
+ * Two distinct of clauses can be added:
+ *
+ * - A 'function' of OVSDB_F_FALSE or OVSDB_F_TRUE adds a Boolean clause. A
+ * "false" clause by itself prevents any rows from being replicated; in
+ * combination with other clauses it has no effect. A "true" clause
+ * causes every row to be replicated, regardless of whether other clauses
+ * exist (thus, a condition that includes "true" is like a condition
+ * without any clauses at all).
+ *
+ * 'column' should be NULL and 'arg' should be an empty datum (initialized
+ * with ovsdb_datum_init_empty()).
+ *
+ * - Other 'functions' add a clause of the form "<column> <function> <arg>",
+ * e.g. "column == 5" or "column <= 10". In this case, 'arg' must have a
+ * type that is compatible with 'column'.
+ */
+void
+ovsdb_idl_condition_add_clause(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_table_class *tc,
+ enum ovsdb_function function,
+ const struct ovsdb_idl_column *column,
+ const struct ovsdb_datum *arg)
+{
+ struct ovsdb_idl_table *table = ovsdb_idl_table_from_class(idl, tc);
+
+ /* Return without doing anything, if this would be a duplicate clause. */
+ if (ovsdb_idl_condition_find_clause(table, function, column, arg)) {
+ return;
+ }
struct ovsdb_idl_clause *clause = xzalloc(sizeof *clause);
ovs_list_init(&clause->node);
clause->function = function;
clause->column = column;
- if (column) {
- type = &column->type;
- } else {
- type = &ovsdb_type_boolean;
- }
- ovsdb_datum_clone(&clause->arg, arg, type);
+ ovsdb_datum_clone(&clause->arg, arg,
+ column ? &column->type : &ovsdb_type_boolean);
ovs_list_push_back(&table->condition.clauses, &clause->node);
idl->cond_changed = table->cond_changed = true;
poll_immediate_wake();
}
-void ovsdb_idl_condition_remove_clause(struct ovsdb_idl *idl,
- const struct ovsdb_idl_table_class *tc,
- enum ovsdb_function function,
- const struct ovsdb_idl_column *column,
- struct ovsdb_datum *arg)
+/* If a clause matching (function, column, arg) is included in the condition
+ * for 'tc' within 'idl', removes it. (If this was the last clause included in
+ * the table's condition, then this means that the IDL will begin replicating
+ * every row in the table.) */
+void
+ovsdb_idl_condition_remove_clause(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_table_class *tc,
+ enum ovsdb_function function,
+ const struct ovsdb_idl_column *column,
+ const struct ovsdb_datum *arg)
{
- struct ovsdb_idl_clause *c, *next;
struct ovsdb_idl_table *table = ovsdb_idl_table_from_class(idl, tc);
-
- LIST_FOR_EACH_SAFE(c, next, node, &table->condition.clauses) {
- if (c->function == function &&
- (!column || (c->column == column &&
- ovsdb_datum_equals(&c->arg,
- arg, &column->type)))) {
- ovsdb_idl_clause_free(c);
- idl->cond_changed = table->cond_changed = true;
- poll_immediate_wake();
- return;
- }
+ struct ovsdb_idl_clause *c
+ = ovsdb_idl_condition_find_clause(table, function, column, arg);
+ if (c) {
+ ovsdb_idl_clause_free(c);
+ idl->cond_changed = table->cond_changed = true;
+ poll_immediate_wake();
}
}
@@ -826,13 +868,13 @@ ovsdb_idl_condition_to_json(const struct
ovsdb_idl_condition *cnd)
clauses = xmalloc(n_clauses * sizeof *clauses);
LIST_FOR_EACH (c, node, &cnd->clauses) {
- clauses[i++] = ovsdb_idl_clause_to_json(c);
+ clauses[i++] = ovsdb_idl_clause_to_json(c);
}
return json_array_create(clauses, n_clauses);
}
-static struct json*
+static struct json *
ovsdb_idl_create_cond_change_req(struct ovsdb_idl_table *table)
{
const struct ovsdb_idl_condition *cond = &table->condition;
diff --git a/lib/ovsdb-idl.h b/lib/ovsdb-idl.h
index 45befb0..a0b60e2 100644
--- a/lib/ovsdb-idl.h
+++ b/lib/ovsdb-idl.h
@@ -48,7 +48,6 @@ struct ovsdb_idl_class;
struct ovsdb_idl_row;
struct ovsdb_idl_column;
struct ovsdb_idl_table_class;
-struct ovsdb_idl_condition;
struct uuid;
struct ovsdb_idl *ovsdb_idl_create(const char *remote,
@@ -311,18 +310,15 @@ struct ovsdb_idl_loop {
void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop *);
struct ovsdb_idl_txn *ovsdb_idl_loop_run(struct ovsdb_idl_loop *);
void ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop *);
-
-struct ovsdb_idl_condition {
- const struct ovsdb_idl_table_class *tc;
- struct ovs_list clauses;
-};
-
-struct ovsdb_idl_clause {
- struct ovs_list node;
- enum ovsdb_function function;
- const struct ovsdb_idl_column *column;
- struct ovsdb_datum arg;
-};
+
+/* Conditional Replication
+ * =======================
+ *
+ * By default, when the IDL replicates a particular table in the database, it
+ * replicates every row in the table. These functions allow the client to
+ * specify that only selected rows should be replicated, by constructing a
+ * per-table condition that specifies the rows to replicate.
+ */
void ovsdb_idl_condition_reset(struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc);
@@ -330,11 +326,11 @@ void ovsdb_idl_condition_add_clause(struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc,
enum ovsdb_function function,
const struct ovsdb_idl_column *column,
- struct ovsdb_datum *arg);
+ const struct ovsdb_datum *arg);
void ovsdb_idl_condition_remove_clause(struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc,
enum ovsdb_function function,
const struct ovsdb_idl_column *column,
- struct ovsdb_datum *arg);
+ const struct ovsdb_datum *arg);
#endif /* ovsdb-idl.h */
--
2.1.3
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