server/object.c

   1 /*
   2  * Server-side objects
   3  * These are the server equivalent of K32OBJ
   4  *
   5  * Copyright (C) 1998 Alexandre Julliard
   6  */
   7
   8 #include <assert.h>
   9 #include <limits.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #include "winerror.h"
  14 #include "server.h"
  15 #include "server/thread.h"
  16
  17 int debug_level = 0;
  18
  19 struct object_name
  20 {
  21     struct object_name *next;
  22     struct object      *obj;
  23     int                 len;
  24     char                name[1];
  25 };
  26
  27 #define NAME_HASH_SIZE 37
  28
  29 static struct object_name *names[NAME_HASH_SIZE];
  30
  31 /*****************************************************************/
  32
  33 void *mem_alloc( size_t size )
  34 {
  35     void *ptr = malloc( size );
  36     if (ptr) memset( ptr, 0x55, size );
  37     else if (current) SET_ERROR( ERROR_OUTOFMEMORY );
  38     return ptr;
  39 }
  40
  41 /*****************************************************************/
  42
  43 static int get_name_hash( const char *name )
  44 {
  45     int hash = 0;
  46     while (*name) hash ^= *name++;
  47     return hash % NAME_HASH_SIZE;
  48 }
  49
  50 static struct object_name *add_name( struct object *obj, const char *name )
  51 {
  52     struct object_name *ptr;
  53     int hash = get_name_hash( name );
  54     int len = strlen( name );
  55
  56     if (!(ptr = (struct object_name *)mem_alloc( sizeof(*ptr) + len )))
  57         return NULL;
  58     ptr->next = names[hash];
  59     ptr->obj  = obj;
  60     ptr->len  = len;
  61     strcpy( ptr->name, name );
  62     names[hash] = ptr;
  63     return ptr;
  64 }
  65
  66 static void free_name( struct object *obj )
  67 {
  68     int hash = get_name_hash( obj->name->name );
  69     struct object_name **pptr = &names[hash];
  70     while (*pptr && *pptr != obj->name) pptr = &(*pptr)->next;
  71     assert( *pptr );
  72     *pptr = (*pptr)->next;
  73     free( obj->name );
  74 }
  75
  76 /* initialize an already allocated object */
  77 /* return 1 if OK, 0 on error */
  78 int init_object( struct object *obj, const struct object_ops *ops,
  79                  const char *name )
  80 {
  81     obj->refcount = 1;
  82     obj->ops      = ops;
  83     obj->head     = NULL;
  84     obj->tail     = NULL;
  85     if (!name) obj->name = NULL;
  86     else if (!(obj->name = add_name( obj, name ))) return 0;
  87     return 1;
  88 }
  89
  90 struct object *create_named_object( const char *name, const struct object_ops *ops, size_t size )
  91 {
  92     struct object *obj;
  93     if ((obj = find_object( name )))
  94     {
  95         if (obj->ops == ops)
  96         {
  97             SET_ERROR( ERROR_ALREADY_EXISTS );
  98             return obj;
  99         }
 100         SET_ERROR( ERROR_INVALID_HANDLE );
 101         return NULL;
 102     }
 103     if (!(obj = mem_alloc( size ))) return NULL;
 104     if (!init_object( obj, ops, name ))
 105     {
 106         free( obj );
 107         return NULL;
 108     }
 109     CLEAR_ERROR();
 110     return obj;
 111 }
 112
 113 /* grab an object (i.e. increment its refcount) and return the object */
 114 struct object *grab_object( void *ptr )
 115 {
 116     struct object *obj = (struct object *)ptr;
 117     assert( obj->refcount < INT_MAX );
 118     obj->refcount++;
 119     return obj;
 120 }
 121
 122 /* release an object (i.e. decrement its refcount) */
 123 void release_object( void *ptr )
 124 {
 125     struct object *obj = (struct object *)ptr;
 126     assert( obj->refcount );
 127     if (!--obj->refcount)
 128     {
 129         /* if the refcount is 0, nobody can be in the wait queue */
 130         assert( !obj->head );
 131         assert( !obj->tail );
 132         if (obj->name) free_name( obj );
 133         obj->ops->destroy( obj );
 134     }
 135 }
 136
 137 /* find an object by its name; the refcount is incremented */
 138 struct object *find_object( const char *name )
 139 {
 140     struct object_name *ptr;
 141     if (!name) return NULL;
 142     ptr = names[ get_name_hash( name ) ];
 143     while (ptr && strcmp( ptr->name, name )) ptr = ptr->next;
 144     if (!ptr) return NULL;
 145     return grab_object( ptr->obj );
 146 }