ino.hh

// -*- c-basic-offset: 4; related-file-name: "../../lib/ino.cc" -*-
#ifndef CLICK_INO_HH
#define CLICK_INO_HH
#include <click/router.hh>
CLICK_DECLS
 
#define INO_DEBUG                       0
 
// /click: .e > .h > element names > global handlers [dt_global]
// /click/.e: element numbers [dt_u]
// /click/.e/NUM: handlers [dt_hu]
// /click/.h: global handlers [dt_hh]
// /click/ELEMENTNAME: .h > element names > element handlers [dt_hn]
// /click/ELEMENTNAME/.h: element handlers [dt_hh]
 
class ClickIno { public:
 
    void initialize();
    void cleanup();
 
    uint32_t generation() const         { return _generation; }
 
    // NB: inode number 0 is reserved for the system.
    enum { dt_u = 1U, dt_hh = 2U, dt_hu = 3U, dt_hn = 4U, dt_global = 5U };
    enum { ino_globaldir = (unsigned) (dt_global << 28),
           ino_enumdir = (unsigned) (dt_u << 28) };
    static bool is_handler(unsigned ino)   { return (int32_t) ino < 0; }
    static unsigned dirtype(unsigned ino)  { return ino >> 28; }
    static bool has_element(unsigned ino)  { return ino & 0xFFFFU; }
    static bool has_handlers(unsigned ino) { return ino > (dt_u << 28); }
    static bool has_names(unsigned ino)    { return ino >= (dt_hn << 28); }
    static int ino_element(unsigned ino)   { return (int) (ino & 0xFFFFU) - 1; }
    static int ino_handler(unsigned ino) {
        return (has_element(ino) ? 0 : Router::FIRST_GLOBAL_HANDLER)
            + ((ino >> 16) & 0x7FFFU);
    }
 
    static unsigned make_handler(int e, int hi) {
        return 0x80000000U | ((hi & 0x7FFFU) << 16) | ((e + 1) & 0xFFFFU);
    }
    static unsigned make_dir(unsigned dtype, int e) {
        return (dtype << 28) | ((e + 1) & 0xFFFFU);
    }
 
 
    // These operations should be called with a configuration lock held.
    inline int prepare(Router *router, uint32_t generation);
    int nlink(ino_t ino);
    ino_t lookup(ino_t dir, const String &component);
 
    // readdir handles '..' (f_pos 0) and '.' (f_pos 1).
    // It returns the number of things stored.
    typedef bool (*filldir_t)(const char *name, int name_len, ino_t ino, int dirtype, loff_t f_pos, void *user_data);
    int readdir(ino_t dir, loff_t &f_pos, filldir_t fd, void *user_data);
 
#if INO_DEBUG
    String info() const;
#endif
 
    struct Entry {
        // Name of this entry.
        String name;
 
        // Corresponding eindex plus 1. Might be larger than the number of
        // elements in the router, because of fake directories added for
        // compound "elements".
        uint16_t elementno_plus1;
 
        // '_x[i].xindex' equals the index in _x of the entry for element
        // number 'i - 1'.
        uint16_t xindex;
 
        // Number of child entries. 'name' is guaranteed to be a prefix of
        // every child entry.
        uint16_t skip;
 
        // See enum below. X_FAKE is true on fake directories added for
        // compound elements.
        uint16_t flags;
    };
 
  private:
    enum { X_FAKE = 1 };
 
    Entry* _x;
    int _nentries;
    int _cap;
    Router* _router;
    uint32_t _generation;
 
    inline int xindex(int elementno) const;
    inline int next_xindex(int elementno) const;
    inline int elementno(int xindex) const;
 
    int name_search(const String &n, int first_xi, int last_xi, int name_offset) const;
    int element_name_search(const String &n, int elementno) const;
 
    int grow(int min_size);
    int true_prepare(Router*, uint32_t);
};
 
 
inline int
ClickIno::prepare(Router* router, uint32_t generation)
{
    if (generation != _generation)
        return true_prepare(router, generation);
    else
        return 0;
}
 
inline int
ClickIno::xindex(int elementno) const
{
    assert(elementno >= -1 && elementno < _nentries - 1);
    return _x[elementno + 1].xindex;
}
 
inline int
ClickIno::next_xindex(int elementno) const
{
    int xi = xindex(elementno);
    return xi + _x[xi].skip + 1;
}
 
inline int
ClickIno::elementno(int xindex) const
{
    return _x[xindex].elementno_plus1 - 1;
}
 
CLICK_ENDDECLS
#endif