/*    Copyright 2012 10gen Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

#pragma once

#include <string>
#include <vector>

#include "mongo/base/disallow_copying.h"
#include "mongo/base/initializer_context.h"
#include "mongo/base/initializer_dependency_graph.h"
#include "mongo/base/status.h"
#include "mongo/client/export_macros.h"

namespace mongo {

/**
 * Class representing an initialization process.
 *
 * Such a process is described by a directed acyclic graph of initialization operations, the
 * InitializerDependencyGraph.  One constructs an initialization process by adding nodes and
 * edges to the graph.  Then, one executes the process, causing each initialization operation to
 * execute in an order that respects the programmer-established prerequistes.
 */
class Initializer {
    MONGO_DISALLOW_COPYING(Initializer);

public:
    Initializer();
    ~Initializer();

    /**
     * Get the initializer dependency graph, presumably for the purpose of adding more nodes.
     */
    InitializerDependencyGraph& getInitializerDependencyGraph() {
        return _graph;
    }

    /**
     * Execute the initializer process, using the given argv and environment data as input.
     *
     * Returns Status::OK on success.  All other returns constitute initialization failures,
     * and the thing being initialized should be considered dead in the water.
     */
    Status execute(const InitializerContext::ArgumentVector& args,
                   const InitializerContext::EnvironmentMap& env) const;

private:
    InitializerDependencyGraph _graph;
};

/**
 * Run the global initializers.
 *
 * It's a programming error for this to fail, but if it does it will return a status other
 * than Status::OK.
 *
 * This means that the few initializers that might want to terminate the program by failing
 * should probably arrange to terminate the process themselves.
 */
Status runGlobalInitializers(const InitializerContext::ArgumentVector& args,
                             const InitializerContext::EnvironmentMap& env);

Status runGlobalInitializers(int argc, const char* const* argv, const char* const* envp);

/**
 * Same as runGlobalInitializers(), except prints a brief message to std::cerr
 * and terminates the process on failure.
 */
void runGlobalInitializersOrDie(int argc, const char* const* argv, const char* const* envp);

}  // namespace mongo
