utils/wvmoniker.cc

   1 /*
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * Support for monikers, which are strings that you can pass to a magic
   6  * factory to get objects supporting a particular interface.  See wvmoniker.h.
   7  */
   8 #include "wvmonikerregistry.h"
   9 #include "strutils.h"
  10 #include <wvassert.h>
  11 #include <stdio.h>
  12 #include "wvscatterhash.h"
  13
  14 #if 0
  15 # define DEBUGLOG(fmt, args...) fprintf(stderr, fmt, ## args)
  16 #else
  17 #ifndef _MSC_VER
  18 # define DEBUGLOG(fmt, args...)
  19 #else  // MS Visual C++ doesn't support varags preproc macros
  20 # define DEBUGLOG
  21 #endif
  22 #endif
  23
  24
  25 static unsigned WvHash(const UUID &_uuid)
  26 {
  27     unsigned val = 0;
  28     unsigned int *uuid = (unsigned int *)&_uuid;
  29     int max = sizeof(UUID)/sizeof(*uuid);
  30
  31     for (int count = 0; count < max; count++)
  32         val += uuid[count];
  33
  34     return val;
  35 }
  36
  37
  38 DeclareWvScatterDict(WvMonikerRegistry, UUID, reg_iid);
  39 static WvMonikerRegistryDict *regs;
  40
  41
  42
  43 WvMonikerRegistry::WvMonikerRegistry(const UUID &iid)
  44     : reg_iid(iid)
  45 {
  46     DEBUGLOG("WvMonikerRegistry creating.\n");
  47     refcount = 0;
  48 }
  49
  50
  51 WvMonikerRegistry::~WvMonikerRegistry()
  52 {
  53     DEBUGLOG("WvMonikerRegistry destroying.\n");
  54 }
  55
  56
  57 void WvMonikerRegistry::add(WvStringParm id, WvMonikerCreateFunc *func,
  58                             const bool override)
  59 {
  60     DEBUGLOG("WvMonikerRegistry register(%s).\n", id.cstr());
  61     if (!override) {
  62         RegistrationList::Iter i(list);
  63         for (i.rewind(); i.next(); )
  64             assert(i.ptr()->id != id); //no duplicates without override
  65     }
  66     list.prepend(new Registration(id, func), true);
  67 }
  68
  69
  70 void WvMonikerRegistry::del(WvStringParm id)
  71 {
  72     DEBUGLOG("WvMonikerRegistry unregister(%s).\n", id.cstr());
  73     RegistrationList::Iter i(list);
  74     for (i.rewind(); i.next(); )
  75     {
  76         if (i.ptr()->id == id) {
  77             i.unlink();
  78             return;
  79         }
  80     }
  81
  82     //We should never get here, as we should never be removing elements which don't exist
  83     assert(false);
  84 }
  85
  86
  87 void *WvMonikerRegistry::create(WvStringParm _s, IObject *obj)
  88 {
  89     WvString t(_s);
  90     WvString s(trim_string(t.edit()));
  91
  92     char *cptr = strchr(s.edit(), ':');
  93     if (cptr)
  94         *cptr++ = 0;
  95     else
  96         cptr = (char*)"";
  97
  98     DEBUGLOG("WvMonikerRegistry create object ('%s' '%s').\n", s.cstr(), cptr);
  99
 100     RegistrationList::Iter i(list);
 101     for (i.rewind(); i.next(); )
 102     {
 103         if (i.ptr()->id == s)
 104             return i.ptr()->func(cptr, obj);
 105     }
 106
 107     return NULL;
 108 }
 109
 110
 111 WvMonikerRegistry *WvMonikerRegistry::find_reg(const UUID &iid)
 112 {
 113     DEBUGLOG("WvMonikerRegistry find_reg.\n");
 114
 115     if (!regs)
 116         regs = new WvMonikerRegistryDict(10);
 117
 118     WvMonikerRegistry *reg = (*regs)[iid];
 119
 120     if (!reg)
 121     {
 122         // we have to make one!
 123         reg = new WvMonikerRegistry(iid);
 124         regs->add(reg, true);
 125         reg->addRef(); // one reference for being in the list at all
 126     }
 127
 128     reg->addRef();
 129     return reg;
 130 }
 131
 132
 133 IObject *WvMonikerRegistry::getInterface(const UUID &uuid)
 134 {
 135 #if 0
 136     if (uuid.equals(IObject_IID))
 137     {
 138         addRef();
 139         return this;
 140     }
 141 #endif
 142
 143     // we don't really support any interfaces for now.
 144
 145     return 0;
 146 }
 147
 148
 149 unsigned int WvMonikerRegistry::addRef()
 150 {
 151     DEBUGLOG("WvMonikerRegistry addRef.\n");
 152     return ++refcount;
 153 }
 154
 155
 156 unsigned int WvMonikerRegistry::release()
 157 {
 158     DEBUGLOG("WvMonikerRegistry release.\n");
 159
 160     if (--refcount > 1)
 161         return refcount;
 162
 163     if (refcount == 1)
 164     {
 165         // the list has one reference to us, but it's no longer needed.
 166         // Note: remove() will delete this object!
 167         regs->remove(this);
 168         if (regs->isempty())
 169         {
 170             delete regs;
 171             regs = NULL;
 172         }
 173         return 0;
 174     }
 175
 176     /* protect against re-entering the destructor */
 177     refcount = 1;
 178     delete this;
 179     return 0;
 180 }
 181
 182
 183 WvMonikerBase::WvMonikerBase(const UUID &iid, WvStringParm _id,
 184                              WvMonikerCreateFunc *func, const bool override)
 185     : id(_id)
 186 {
 187     DEBUGLOG("WvMoniker creating(%s).\n", id.cstr());
 188     reg = WvMonikerRegistry::find_reg(iid);
 189     if (reg)
 190         reg->add(id, func, override);
 191 }
 192
 193
 194 WvMonikerBase::~WvMonikerBase()
 195 {
 196     DEBUGLOG("WvMoniker destroying(%s).\n", id.cstr());
 197     if (reg)
 198     {
 199         reg->del(id);
 200         WVRELEASE(reg);
 201     }
 202 }
 203
 204
 205 void *wvcreate(const UUID &iid, WvStringParm moniker, IObject *obj)
 206 {
 207     assert(!moniker.isnull());
 208     // fprintf(stderr, "wvcreate: Looking for '%s'\n", moniker.cstr());
 209     WvMonikerRegistry *reg = WvMonikerRegistry::find_reg(iid);
 210     if (reg)
 211     {
 212         void *ret = reg->create(moniker, obj);
 213         WVRELEASE(reg);
 214         return ret;
 215     }
 216     else
 217         return NULL;
 218 }