rom/oop/obtainattrbase.c

   1 /*
   2     Copyright © 1995-2019, 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     /* Has ID already been mapped to a numeric ID? */
  76     idb = (struct iid_bucket *)iidtable->Lookup(iidtable, (IPTR)interfaceID, GetOBase(OOPBase));
  77     if (idb)
  78     {
  79
  80         /* If so, it has been stored in the hashtable, and we have
  81         ** to return the same numeric ID now.
  82         */
  83         if (idb->attrbase == (ULONG)-1)
  84         {
  85             idb->attrbase = ++GetOBase(OOPBase)->ob_CurrentAttrBase;
  86         }
  87
  88         base = idb->attrbase;
  89         base <<= NUM_METHOD_BITS;
  90
  91         D(bug("Bucket found: id=%ld\n", base));
  92     }
  93     else
  94     {
  95
  96         D(bug("No existing bucket\n"));
  97
  98
  99         /* If not, then map it and create a new bucket in the
 100         ** hashtable to store it
 101         */
 102         idb = AllocMem(sizeof (struct iid_bucket), MEMF_ANY|MEMF_CLEAR);
 103         if (idb)
 104         {
 105             idb->interface_id = AllocVec(strlen(interfaceID) + 1, MEMF_ANY);
 106             if (idb->interface_id)
 107             {
 108                 D(bug("Allocated bucket\n"));
 109                 strcpy(idb->interface_id, interfaceID);
 110
 111                 /* Get next free ID, and increase the free ID count to mark it as used */
 112                 base = idb->attrbase = ++GetOBase(OOPBase)->ob_CurrentAttrBase;
 113
 114                 base <<= NUM_METHOD_BITS;
 115
 116                 /* Methodbase not inited yet */
 117                 idb->methodbase = (ULONG)-1;
 118
 119                 /* Insert bucket into hash table */
 120                 InsertBucket(iidtable, (struct Bucket *)idb, GetOBase(OOPBase));
 121             }
 122             else
 123             {
 124                 FreeMem(idb, sizeof (struct iid_bucket));
 125
 126 /* Throw exception here ? */
 127                 base = 0UL;
 128             }
 129         }
 130     }
 131
 132     if (base)
 133     {
 134         /* Increase refcount of bucket */
 135         idb->refcount ++;
 136     }
 137
 138     ReleaseSemaphore(&GetOBase(OOPBase)->ob_IIDTableLock);
 139
 140     ReturnInt ("OOP_ObtainAttrBase", OOP_AttrBase, base);
 141
 142     AROS_LIBFUNC_EXIT
 143
 144 } /* OOP_ObtainAttrBase  */
 145