namespace_index.h

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// namespace_index.h

#pragma once

#include <list>
#include <string>

#include "mongo/base/disallow_copying.h"
#include "mongo/db/storage/mmap_v1/catalog/namespace.h"
#include "mongo/db/storage/mmap_v1/diskloc.h"
#include "mongo/db/storage/mmap_v1/durable_mapped_file.h"

namespace mongo {

class NamespaceDetails;
class NamespaceHashTable;
class OperationContext;

/* NamespaceIndex is the ".ns" file you see in the data directory.  It is the "system catalog"
   if you will: at least the core parts.  (Additional info in system.* collections.)
*/
class NamespaceIndex {
    MONGO_DISALLOW_COPYING(NamespaceIndex);

public:
    NamespaceIndex(OperationContext* opCtx, const std::string& dir, const std::string& database);
    ~NamespaceIndex();

    void close(OperationContext* opCtx) {
        LockMongoFilesExclusive lock(opCtx);
        _f.close(opCtx);
    }

    /* returns true if the file represented by this file exists on disk */
    bool pathExists() const;

    void init(OperationContext* opCtx);

    void add_ns(OperationContext* opCtx, StringData ns, const DiskLoc& loc, bool capped);
    void add_ns(OperationContext* opCtx, StringData ns, const NamespaceDetails* details);
    void add_ns(OperationContext* opCtx, const Namespace& ns, const NamespaceDetails* details);

    NamespaceDetails* details(StringData ns) const;
    NamespaceDetails* details(const Namespace& ns) const;

    void kill_ns(OperationContext* opCtx, StringData ns);

    bool allocated() const {
        return _ht.get() != 0;
    }

    void getCollectionNamespaces(std::list<std::string>* tofill) const;

    boost::filesystem::path path() const;

    unsigned long long fileLength() const {
        return _f.length();
    }

private:
    void maybeMkdir() const;

    const std::string _dir;
    const std::string _database;

    DurableMappedFile _f;
    std::unique_ptr<NamespaceHashTable> _ht;
};
}