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 "thread.h"
  15
  16 int debug_level = 0;
  17
  18 struct object_name
  19 {
  20     struct object_name *next;
  21     struct object      *obj;
  22     int                 len;
  23     char                name[1];
  24 };
  25
  26 #define NAME_HASH_SIZE 37
  27
  28 static struct object_name *names[NAME_HASH_SIZE];
  29
  30 /*****************************************************************/
  31
  32 void *mem_alloc( size_t size )
  33 {
  34     void *ptr = malloc( size );
  35     if (ptr) memset( ptr, 0x55, size );
  36     else if (current) SET_ERROR( ERROR_OUTOFMEMORY );
  37     return ptr;
  38 }
  39
  40 /*****************************************************************/
  41
  42 static int get_name_hash( const char *name )
  43 {
  44     int hash = 0;
  45     while (*name) hash ^= *name++;
  46     return hash % NAME_HASH_SIZE;
  47 }
  48
  49 static struct object_name *add_name( struct object *obj, const char *name )
  50 {
  51     struct object_name *ptr;
  52     int hash = get_name_hash( name );
  53     int len = strlen( name );
  54
  55     if (!(ptr = (struct object_name *)mem_alloc( sizeof(*ptr) + len )))
  56         return NULL;
  57     ptr->next = names[hash];
  58     ptr->obj  = obj;
  59     ptr->len  = len;
  60     strcpy( ptr->name, name );
  61     names[hash] = ptr;
  62     return ptr;
  63 }
  64
  65 static void free_name( struct object *obj )
  66 {
  67     int hash = get_name_hash( obj->name->name );
  68     struct object_name **pptr = &names[hash];
  69     while (*pptr && *pptr != obj->name) pptr = &(*pptr)->next;
  70     assert( *pptr );
  71     *pptr = (*pptr)->next;
  72     free( obj->name );
  73 }
  74
  75 /* initialize an already allocated object */
  76 /* return 1 if OK, 0 on error */
  77 int init_object( struct object *obj, const struct object_ops *ops,
  78                  const char *name )
  79 {
  80     obj->refcount = 1;
  81     obj->ops      = ops;
  82     obj->head     = NULL;
  83     obj->tail     = NULL;
  84     if (!name) obj->name = NULL;
  85     else if (!(obj->name = add_name( obj, name ))) return 0;
  86     return 1;
  87 }
  88
  89 struct object *create_named_object( const char *name, const struct object_ops *ops, size_t size )
  90 {
  91     struct object *obj;
  92     if ((obj = find_object( name )))
  93     {
  94         if (obj->ops == ops)
  95         {
  96             SET_ERROR( ERROR_ALREADY_EXISTS );
  97             return obj;
  98         }
  99         SET_ERROR( ERROR_INVALID_HANDLE );
 100         return NULL;
 101     }
 102     if (!(obj = mem_alloc( size ))) return NULL;
 103     if (!init_object( obj, ops, name ))
 104     {
 105         free( obj );
 106         return NULL;
 107     }
 108     CLEAR_ERROR();
 109     return obj;
 110 }
 111
 112 /* return a pointer to the object name, or to an empty string */
 113 const char *get_object_name( struct object *obj )
 114 {
 115     if (!obj->name) return "";
 116     return obj->name->name;
 117 }
 118
 119 /* grab an object (i.e. increment its refcount) and return the object */
 120 struct object *grab_object( void *ptr )
 121 {
 122     struct object *obj = (struct object *)ptr;
 123     assert( obj->refcount < INT_MAX );
 124     obj->refcount++;
 125     return obj;
 126 }
 127
 128 /* release an object (i.e. decrement its refcount) */
 129 void release_object( void *ptr )
 130 {
 131     struct object *obj = (struct object *)ptr;
 132     assert( obj->refcount );
 133     if (!--obj->refcount)
 134     {
 135         /* if the refcount is 0, nobody can be in the wait queue */
 136         assert( !obj->head );
 137         assert( !obj->tail );
 138         if (obj->name) free_name( obj );
 139         obj->ops->destroy( obj );
 140     }
 141 }
 142
 143 /* find an object by its name; the refcount is incremented */
 144 struct object *find_object( const char *name )
 145 {
 146     struct object_name *ptr;
 147     if (!name) return NULL;
 148     ptr = names[ get_name_hash( name ) ];
 149     while (ptr && strcmp( ptr->name, name )) ptr = ptr->next;
 150     if (!ptr) return NULL;
 151     return grab_object( ptr->obj );
 152 }
 153
 154 /* functions for unimplemented object operations */
 155
 156 int no_add_queue( struct object *obj, struct wait_queue_entry *entry )
 157 {
 158     SET_ERROR( ERROR_INVALID_HANDLE );
 159     return 0;
 160 }
 161
 162 int no_satisfied( struct object *obj, struct thread *thread )
 163 {
 164     return 0;  /* not abandoned */
 165 }
 166
 167 int no_read_fd( struct object *obj )
 168 {
 169     SET_ERROR( ERROR_INVALID_HANDLE );
 170     return -1;
 171 }
 172
 173 int no_write_fd( struct object *obj )
 174 {
 175     SET_ERROR( ERROR_INVALID_HANDLE );
 176     return -1;
 177 }
 178
 179 int no_flush( struct object *obj )
 180 {
 181     SET_ERROR( ERROR_INVALID_HANDLE );
 182     return 0;
 183 }
 184
 185 int no_get_file_info( struct object *obj, struct get_file_info_reply *info )
 186 {
 187     SET_ERROR( ERROR_INVALID_HANDLE );
 188     return 0;
 189 }
 190
 191 void default_select_event( int fd, int event, void *private )
 192 {
 193     struct object *obj = (struct object *)private;
 194     assert( obj );
 195     wake_up( obj, 0 );
 196 }