mariadb/storage/tokudb/PerconaFT/locktree/tests/wfg_test.cc

/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*======
This file is part of PerconaFT.


Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.

----------------------------------------

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License, version 3,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.
======= */

#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."

#include <locktree/wfg.h>

namespace toku {

enum {
    WFG_TEST_MAX_TXNID = 10
};

struct visit_extra {
    bool nodes_visited[WFG_TEST_MAX_TXNID];
    bool edges_visited[WFG_TEST_MAX_TXNID][WFG_TEST_MAX_TXNID];

    void clear(void) {
        memset(nodes_visited, 0, sizeof(nodes_visited));
        memset(edges_visited, 0, sizeof(edges_visited));
    }
};

// wfg node visit callback
static int visit_nodes(TXNID txnid, void *extra) {
    visit_extra *ve = static_cast<visit_extra *>(extra);
    invariant(txnid < WFG_TEST_MAX_TXNID);
    invariant(!ve->nodes_visited[txnid]);
    ve->nodes_visited[txnid] = true;
    return 0;
}

// wfg edge visit callback
static int visit_edges(TXNID txnid, TXNID edge_txnid, void *extra) {
    visit_extra *ve = static_cast<visit_extra *>(extra);
    invariant(txnid < WFG_TEST_MAX_TXNID);
    invariant(edge_txnid < WFG_TEST_MAX_TXNID);
    invariant(!ve->edges_visited[txnid][edge_txnid]);
    ve->edges_visited[txnid][edge_txnid] = true;
    return 0;
}

// the graph should only have 3 nodes labelled 0 1 and 2
static void verify_only_nodes_012_exist(wfg *g) {
    visit_extra ve;
    ve.clear();
    g->apply_nodes(visit_nodes, &ve);
    for (int i = 0; i < WFG_TEST_MAX_TXNID; i++) {
        if (i == 0 || i == 1 || i == 2) {
            invariant(ve.nodes_visited[i]);
        } else {
            invariant(!ve.nodes_visited[i]);
        }
    }
}

// the graph should only have edges 0->1 and 1->2
static void verify_only_edges_01_12_exist(wfg *g) {
    visit_extra ve;
    ve.clear();
    g->apply_edges(0, visit_edges, &ve);
    g->apply_edges(1, visit_edges, &ve);
    g->apply_edges(2, visit_edges, &ve);
    for (int i = 0; i < WFG_TEST_MAX_TXNID; i++) {
        for (int j = 0; j < WFG_TEST_MAX_TXNID; j++) {
            if ((i == 0 && j == 1) || (i == 1 && j == 2)) {
                invariant(ve.edges_visited[i][j]);
            } else {
                invariant(!ve.edges_visited[i][j]);
            }
        }
    }
}

static void test_add_cycle_exists() {
    wfg g;
    g.create();

    // test that adding edges works and is idempotent

    g.add_edge(0, 1);
    invariant(g.node_exists(0));
    invariant(g.node_exists(1));
    g.add_edge(1, 2);
    invariant(g.node_exists(0));
    invariant(g.node_exists(1));
    invariant(g.node_exists(2));

    // verify that adding edges with the same nodes
    // does not store multiple nodes with the same txnid.
    verify_only_nodes_012_exist(&g);
    verify_only_edges_01_12_exist(&g);
    g.add_edge(0, 1);
    g.add_edge(1, 2);
    verify_only_nodes_012_exist(&g);
    verify_only_edges_01_12_exist(&g);

    // confirm that no cycle exists from txnid 0 1 or 2
    invariant(!g.cycle_exists_from_txnid(0));
    invariant(!g.cycle_exists_from_txnid(1));
    invariant(!g.cycle_exists_from_txnid(2));

    // add 2,3 and 3,1. now there should be a cycle
    // from 1 2 and 3 but not 0.
    //
    // 0 --> 1 -->  2
    //       ^    /
    //       ^ 3 <
    g.add_edge(2, 3);
    g.add_edge(3, 1);
    invariant(!g.cycle_exists_from_txnid(0));
    invariant(g.cycle_exists_from_txnid(1));
    invariant(g.cycle_exists_from_txnid(2));
    invariant(g.cycle_exists_from_txnid(3));

    // add 2,4. should not have a cycle from 4, but yes from 2.
    g.add_edge(2, 4);
    invariant(!g.cycle_exists_from_txnid(4));
    invariant(g.cycle_exists_from_txnid(2));

    g.destroy();
}

static void test_find_cycles() {
    wfg g;
    g.create();

    // TODO: verify that finding cycles works

    g.destroy();
}

} /* namespace toku */

int main(void) {
    toku::test_add_cycle_exists();
    toku::test_find_cycles();
    return 0;
}