rom/oop/obtainattrbase.c

   1 /*
   2     Copyright © 1995-2013, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: OOP function OOP_ObtainAttrBase
   6     Lang: english
   7 */
   8
   9 #include "intern.h"
  10 #include "hash.h"
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <string.h>
  15
  16 #include <proto/exec.h>
  17 #include <exec/memory.h>
  18 #include <aros/libcall.h>
  19
  20 #include <aros/debug.h>
  21
  22         AROS_LH1(OOP_AttrBase, OOP_ObtainAttrBase,
  23
  24 /*  SYNOPSIS */
  25         AROS_LHA(CONST_STRPTR   , interfaceID, A0),
  26
  27 /*  LOCATION */
  28         struct Library *, OOPBase, 6, OOP)
  29
  30 /*  FUNCTION
  31         Maps a globally unique string interface ID into
  32         a numeric AttrBase ID that is unique on a
  33         per machine basis. The AttrBase can be combined
  34         with attribute offsets to generate attribute IDs.
  35
  36     INPUTS
  37         interfaceID     - globally unique interface identifier.
  38                           for which to obtain an attrbase.
  39
  40     RESULT
  41         Numeric AttrBase that is unique for this machine.
  42         A return value of 0 means that the call failed.
  43
  44     NOTES
  45         Obtained attrbases should be released with ReleaseAttrBase().
  46
  47     EXAMPLE
  48         #define aTimer_CurrentTime    (__AB_Timer + aoTime_CurrentTime)
  49
  50         ..
  51         __AB_Timer = OOP_ObtainAttrBase(IID_Timer);
  52
  53         SetAttrs(timer, aTimer_CurrentTime, "10:37:00");
  54
  55
  56     BUGS
  57
  58     SEE ALSO
  59
  60     INTERNALS
  61
  62 ******************************************************************************/
  63 {
  64     AROS_LIBFUNC_INIT
  65
  66     /* Look up ID */
  67     struct iid_bucket *idb;
  68     struct HashTable *iidtable = GetOBase(OOPBase)->ob_IIDTable;
  69     ULONG base = (ULONG)-1;
  70
  71     EnterFunc(bug("OOP_ObtainAttrBase(interfaceID=%s)\n", interfaceID));
  72
  73     ObtainSemaphore(&GetOBase(OOPBase)->ob_IIDTableLock);
  74
  75
  76     /* Has ID already been mapped to a numeric ID? */
  77     idb = (struct iid_bucket *)iidtable->Lookup(iidtable, (IPTR)interfaceID, GetOBase(OOPBase));
  78     if (idb)
  79     {
  80
  81         /* If so, it has been stored in the hashtable, and we have
  82         ** to return the same numeric ID now.
  83         */
  84         if (idb->attrbase == (ULONG)-1)
  85         {
  86             idb->attrbase = GetOBase(OOPBase)->ob_CurrentAttrBase ++;
  87         }
  88
  89         base = idb->attrbase;
  90         base <<= NUM_METHOD_BITS;
  91
  92         D(bug("Bucket found: id=%ld\n", base));
  93     }
  94     else
  95     {
  96
  97         D(bug("No existing bucket\n"));
  98
  99
 100         /* If not, then map it and create a new bucket in the
 101         ** hashtable to store it
 102         */
 103         idb = AllocMem(sizeof (struct iid_bucket), MEMF_ANY|MEMF_CLEAR);
 104         if (idb)
 105         {
 106             idb->interface_id = AllocVec(strlen(interfaceID) + 1, MEMF_ANY);
 107             if (idb->interface_id)
 108             {
 109                 D(bug("Allocated bucket\n"));
 110                 strcpy(idb->interface_id, interfaceID);
 111
 112                 /* Get next free ID, and increase the free ID count to mark it as used */
 113                 base = idb->attrbase = ++ GetOBase(OOPBase)->ob_CurrentAttrBase;
 114
 115                 base <<= NUM_METHOD_BITS;
 116
 117                 /* Methodbase not inited yet */
 118                 idb->methodbase = (ULONG)-1;
 119
 120                 /* Insert bucket into hash table */
 121                 InsertBucket(iidtable, (struct Bucket *)idb, GetOBase(OOPBase));
 122             }
 123             else
 124             {
 125                 FreeMem(idb, sizeof (struct iid_bucket));
 126
 127 /* Throw exception here ? */
 128                 base = 0UL;
 129             }
 130         }
 131     }
 132
 133     if (base)
 134     {
 135         /* Increase refcount of bucket */
 136         idb->refcount ++;
 137     }
 138
 139     ReleaseSemaphore(&GetOBase(OOPBase)->ob_IIDTableLock);
 140
 141     ReturnInt ("OOP_ObtainAttrBase", OOP_AttrBase, base);
 142
 143     AROS_LIBFUNC_EXIT
 144
 145 } /* OOP_ObtainAttrBase  */
 146