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_NULL,
  35 };
  36
  37 /* Generic opener that knows about all the backends */
  38 struct db_conn *db_open(enum backend_type type, const char *name, int flags);
  39
  40 /* Returns the backend type for the given name. */
  41 enum backend_type be_type_from_str(const char *name);
  42
  43 /* Returns the backend name for the given type. */
  44 const char *be_str_from_type(enum backend_type type);
  45
  46 /* String containing a list of all supported backends */
  47 #if BE_ENABLE_QDBM
  48   #define _QDBM_SUPP "qdbm "
  49 #else
  50   #define _QDBM_SUPP ""
  51 #endif
  52
  53 #if BE_ENABLE_BDB
  54   #define _BDB_SUPP "bdb "
  55 #else
  56   #define _BDB_SUPP ""
  57 #endif
  58
  59 #if BE_ENABLE_TC
  60   #define _TC_SUPP "tc "
  61 #else
  62   #define _TC_SUPP ""
  63 #endif
  64
  65 #if BE_ENABLE_TDB
  66   #define _TDB_SUPP "tdb "
  67 #else
  68   #define _TDB_SUPP ""
  69 #endif
  70
  71 #if BE_ENABLE_NULL
  72   #define _NULL_SUPP "null "
  73 #else
  74   #define _NULL_SUPP ""
  75 #endif
  76
  77 #define SUPPORTED_BE _QDBM_SUPP _BDB_SUPP _TC_SUPP _TDB_SUPP _NULL_SUPP
  78
  79
  80 /* Default backend */
  81 #if BE_ENABLE_TDB
  82   #define DEFAULT_BE BE_TDB
  83   #define DEFAULT_BE_NAME "tdb"
  84 #elif BE_ENABLE_TC
  85   #define DEFAULT_BE BE_TC
  86   #define DEFAULT_BE_NAME "tc"
  87 #elif BE_ENABLE_QDBM
  88   #define DEFAULT_BE BE_QDBM
  89   #define DEFAULT_BE_NAME "qdbm"
  90 #elif BE_ENABLE_BDB
  91   #define DEFAULT_BE BE_BDB
  92   #define DEFAULT_BE_NAME "bdb"
  93 #elif BE_ENABLE_NULL
  94   #warning "using null backend as the default"
  95   #define DEFAULT_BE BE_NULL
  96   #define DEFAULT_BE_NAME "null"
  97 #else
  98   #error "no backend available"
  99 #endif
 100
 101
 102 #endif
 103