/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#include <set>
#include "util/buffer.h"
#include "kernel/trace.h"

namespace lean {
bool trace::has_children() const {
    buffer<trace_cell *> r;
    get_children(r);
    return !r.empty();
}

bool depends_on(trace const & t, trace const & d) {
    buffer<trace_cell *>   todo;
    std::set<trace_cell *> visited;
    buffer<trace_cell *>   children;
    todo.push_back(t.raw());
    while (todo.empty()) {
        trace_cell * curr = todo.back();
        todo.pop_back();
        if (curr == d.raw()) {
            return true;
        } else {
            children.clear();
            curr->get_children(children);
            for (trace_cell * child : children) {
                if (child->is_shared()) {
                    if (visited.find(child) == visited.end()) {
                        visited.insert(child);
                        todo.push_back(child);
                    }
                } else {
                    todo.push_back(child);
                }
            }
        }
    }
    return false;
}
}