nmdb/be.h

   1
   2 #ifndef _BE_H
   3 #define _BE_H
   4
   5 #include <stddef.h>     /* size_t */
   6
   7 struct db_conn {
   8         /* This is where the backend sets a reference to the connection, which
   9          * will be properly casted when needed */
  10         void *conn;
  11
  12         /* Operations */
  13         int (*set)(struct db_conn *db, const unsigned char *key, size_t ksize,
  14                         unsigned char *val, size_t vsize);
  15         int (*get)(struct db_conn *db, const unsigned char *key, size_t ksize,
  16                         unsigned char *val, size_t *vsize);
  17         int (*del)(struct db_conn *db, const unsigned char *key, size_t ksize);
  18         int (*firstkey)(struct db_conn *db, unsigned char *key, size_t *ksize);
  19         int (*nextkey)(struct db_conn *db,
  20                         const unsigned char *key, size_t ksize,
  21                         unsigned char *nextkey, size_t *nksize);
  22         int (*close)(struct db_conn *db);
  23 };
  24
  25 enum backend_type {
  26         /* The first two are special, used to indicate unknown and unsupported
  27          * backends */
  28         BE_UNKNOWN = -2,
  29         BE_UNSUPPORTED = -1,
  30         BE_QDBM = 1,
  31         BE_BDB,
  32         BE_TC,
  33         BE_TDB,
  34         BE_LEVELDB,
  35         BE_NULL,
  36 };
  37
  38 /* Generic opener that knows about all the backends */
  39 struct db_conn *db_open(enum backend_type type, const char *name, int flags);
  40
  41 /* Returns the backend type for the given name. */
  42 enum backend_type be_type_from_str(const char *name);
  43
  44 /* Returns the backend name for the given type. */
  45 const char *be_str_from_type(enum backend_type type);
  46
  47 /* String containing a list of all supported backends */
  48 #if BE_ENABLE_QDBM
  49   #define _QDBM_SUPP "qdbm "
  50 #else
  51   #define _QDBM_SUPP ""
  52 #endif
  53
  54 #if BE_ENABLE_BDB
  55   #define _BDB_SUPP "bdb "
  56 #else
  57   #define _BDB_SUPP ""
  58 #endif
  59
  60 #if BE_ENABLE_TC
  61   #define _TC_SUPP "tc "
  62 #else
  63   #define _TC_SUPP ""
  64 #endif
  65
  66 #if BE_ENABLE_TDB
  67   #define _TDB_SUPP "tdb "
  68 #else
  69   #define _TDB_SUPP ""
  70 #endif
  71
  72 #if BE_ENABLE_LEVELDB
  73   #define _LEVELDB_SUPP "leveldb "
  74 #else
  75   #define _LEVELDB_SUPP ""
  76 #endif
  77
  78 #if BE_ENABLE_NULL
  79   #define _NULL_SUPP "null "
  80 #else
  81   #define _NULL_SUPP ""
  82 #endif
  83
  84 #define SUPPORTED_BE \
  85         _QDBM_SUPP _BDB_SUPP _TC_SUPP _TDB_SUPP _LEVELDB_SUPP _NULL_SUPP
  86
  87
  88 /* Default backend */
  89 #if BE_ENABLE_TDB
  90   #define DEFAULT_BE BE_TDB
  91   #define DEFAULT_BE_NAME "tdb"
  92 #elif BE_ENABLE_TC
  93   #define DEFAULT_BE BE_TC
  94   #define DEFAULT_BE_NAME "tc"
  95 #elif BE_ENABLE_QDBM
  96   #define DEFAULT_BE BE_QDBM
  97   #define DEFAULT_BE_NAME "qdbm"
  98 #elif BE_ENABLE_BDB
  99   #define DEFAULT_BE BE_BDB
 100   #define DEFAULT_BE_NAME "bdb"
 101 #elif BE_ENABLE_LEVELDB
 102   #define DEFAULT_BE BE_LEVELDB
 103   #define DEFAULT_BE_NAME "leveldb"
 104 #elif BE_ENABLE_NULL
 105   #warning "using null backend as the default"
 106   #define DEFAULT_BE BE_NULL
 107   #define DEFAULT_BE_NAME "null"
 108 #else
 109   #error "no backend available"
 110 #endif
 111
 112
 113 #endif
 114