/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-dataslot.c storing data on objects
*
* Copyright (C) 2003 Red Hat, Inc.
*
* Licensed under the Academic Free License version 2.1
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <config.h>
#include "dbus-dataslot.h"
#include "dbus-threads-internal.h"
/**
* @defgroup DBusDataSlot Data slots
* @ingroup DBusInternals
* @brief Storing data by ID
*
* Types and functions related to storing data by an
* allocated ID. This is used for dbus_connection_set_data(),
* dbus_server_set_data(), etc.
* @{
*/
/**
* Initializes a data slot allocator object, used to assign
* integer IDs for data slots.
*
* @param allocator the allocator to initialize
*/
dbus_bool_t
_dbus_data_slot_allocator_init (DBusDataSlotAllocator *allocator)
{
allocator->allocated_slots = NULL;
allocator->n_allocated_slots = 0;
allocator->n_used_slots = 0;
allocator->lock_loc = NULL;
return TRUE;
}
/**
* Allocates an integer ID to be used for storing data
* in a #DBusDataSlotList. If the value at *slot_id_p is
* not -1, this function just increments the refcount for
* the existing slot ID. If the value is -1, a new slot ID
* is allocated and stored at *slot_id_p.
*
* @param allocator the allocator
* @param mutex_loc the location lock for this allocator
* @param slot_id_p address to fill with the slot ID
* @returns #TRUE on success
*/
dbus_bool_t
_dbus_data_slot_allocator_alloc (DBusDataSlotAllocator *allocator,
DBusRMutex **mutex_loc,
dbus_int32_t *slot_id_p)
{
dbus_int32_t slot;
_dbus_rmutex_lock (*mutex_loc);
if (allocator->n_allocated_slots == 0)
{
_dbus_assert (allocator->lock_loc == NULL);
allocator->lock_loc = mutex_loc;
}
else if (allocator->lock_loc != mutex_loc)
{
_dbus_warn_check_failed ("D-Bus threads were initialized after first using the D-Bus library. If your application does not directly initialize threads or use D-Bus, keep in mind that some library or plugin may have used D-Bus or initialized threads behind your back. You can often fix this problem by calling dbus_init_threads() or dbus_g_threads_init() early in your main() method, before D-Bus is used.\n");
_dbus_assert_not_reached ("exiting");
}
if (*slot_id_p >= 0)
{
slot = *slot_id_p;
_dbus_assert (slot < allocator->n_allocated_slots);
_dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
allocator->allocated_slots[slot].refcount += 1;
goto out;
}
_dbus_assert (*slot_id_p < 0);
if (allocator->n_used_slots < allocator->n_allocated_slots)
{
slot = 0;
while (slot < allocator->n_allocated_slots)
{
if (allocator->allocated_slots[slot].slot_id < 0)
{
allocator->allocated_slots[slot].slot_id = slot;
allocator->allocated_slots[slot].refcount = 1;
allocator->n_used_slots += 1;
break;
}
++slot;
}
_dbus_assert (slot < allocator->n_allocated_slots);
}
else
{
DBusAllocatedSlot *tmp;
slot = -1;
tmp = dbus_realloc (allocator->allocated_slots,
sizeof (DBusAllocatedSlot) * (allocator->n_allocated_slots + 1));
if (tmp == NULL)
goto out;
allocator->allocated_slots = tmp;
slot = allocator->n_allocated_slots;
allocator->n_allocated_slots += 1;
allocator->n_used_slots += 1;
allocator->allocated_slots[slot].slot_id = slot;
allocator->allocated_slots[slot].refcount = 1;
}
_dbus_assert (slot >= 0);
_dbus_assert (slot < allocator->n_allocated_slots);
_dbus_assert (*slot_id_p < 0);
_dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
_dbus_assert (allocator->allocated_slots[slot].refcount == 1);
*slot_id_p = slot;
_dbus_verbose ("Allocated slot %d on allocator %p total %d slots allocated %d used\n",
slot, allocator, allocator->n_allocated_slots, allocator->n_used_slots);
out:
_dbus_rmutex_unlock (*(allocator->lock_loc));
return slot >= 0;
}
/**
* Deallocates an ID previously allocated with
* _dbus_data_slot_allocator_alloc(). Existing data stored on
* existing #DBusDataSlotList objects with this ID will be freed when the
* data list is finalized, but may not be retrieved (and may only be
* replaced if someone else reallocates the slot).
* The slot value is reset to -1 if this is the last unref.
*
* @param allocator the allocator
* @param slot_id_p address where we store the slot
*/
void
_dbus_data_slot_allocator_free (DBusDataSlotAllocator *allocator,
dbus_int32_t *slot_id_p)
{
_dbus_rmutex_lock (*(allocator->lock_loc));
_dbus_assert (*slot_id_p < allocator->n_allocated_slots);
_dbus_assert (allocator->allocated_slots[*slot_id_p].slot_id == *slot_id_p);
_dbus_assert (allocator->allocated_slots[*slot_id_p].refcount > 0);
allocator->allocated_slots[*slot_id_p].refcount -= 1;
if (allocator->allocated_slots[*slot_id_p].refcount > 0)
{
_dbus_rmutex_unlock (*(allocator->lock_loc));
return;
}
/* refcount is 0, free the slot */
_dbus_verbose ("Freeing slot %d on allocator %p total %d allocated %d used\n",
*slot_id_p, allocator, allocator->n_allocated_slots, allocator->n_used_slots);
allocator->allocated_slots[*slot_id_p].slot_id = -1;
*slot_id_p = -1;
allocator->n_used_slots -= 1;
if (allocator->n_used_slots == 0)
{
DBusRMutex **mutex_loc = allocator->lock_loc;
dbus_free (allocator->allocated_slots);
allocator->allocated_slots = NULL;
allocator->n_allocated_slots = 0;
allocator->lock_loc = NULL;
_dbus_rmutex_unlock (*mutex_loc);
}
else
{
_dbus_rmutex_unlock (*(allocator->lock_loc));
}
}
/**
* Initializes a slot list.
* @param list the list to initialize.
*/
void
_dbus_data_slot_list_init (DBusDataSlotList *list)
{
list->slots = NULL;
list->n_slots = 0;
}
/**
* Stores a pointer in the data slot list, along with an optional
* function to be used for freeing the data when the data is set
* again, or when the slot list is finalized. The slot number must
* have been allocated with _dbus_data_slot_allocator_alloc() for the
* same allocator passed in here. The same allocator has to be used
* with the slot list every time.
*
* @param allocator the allocator to use
* @param list the data slot list
* @param slot the slot number
* @param data the data to store
* @param free_data_func finalizer function for the data
* @param old_free_func free function for any previously-existing data
* @param old_data previously-existing data, should be freed with old_free_func
* @returns #TRUE if there was enough memory to store the data
*/
dbus_bool_t
_dbus_data_slot_list_set (DBusDataSlotAllocator *allocator,
DBusDataSlotList *list,
int slot,
void *data,
DBusFreeFunction free_data_func,
DBusFreeFunction *old_free_func,
void **old_data)
{
#ifndef DBUS_DISABLE_ASSERT
/* We need to take the allocator lock here, because the allocator could
* be e.g. realloc()ing allocated_slots. We avoid doing this if asserts
* are disabled, since then the asserts are empty.
*/
_dbus_rmutex_lock (*(allocator->lock_loc));
_dbus_assert (slot < allocator->n_allocated_slots);
_dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
_dbus_rmutex_unlock (*(allocator->lock_loc));
#endif
if (slot >= list->n_slots)
{
DBusDataSlot *tmp;
int i;
tmp = dbus_realloc (list->slots,
sizeof (DBusDataSlot) * (slot + 1));
if (tmp == NULL)
return FALSE;
list->slots = tmp;
i = list->n_slots;
list->n_slots = slot + 1;
while (i < list->n_slots)
{
list->slots[i].data = NULL;
list->slots[i].free_data_func = NULL;
++i;
}
}
_dbus_assert (slot < list->n_slots);
*old_data = list->slots[slot].data;
*old_free_func = list->slots[slot].free_data_func;
list->slots[slot].data = data;
list->slots[slot].free_data_func = free_data_func;
return TRUE;
}
/**
* Retrieves data previously set with _dbus_data_slot_list_set_data().
* The slot must still be allocated (must not have been freed).
*
* @param allocator the allocator slot was allocated from
* @param list the data slot list
* @param slot the slot to get data from
* @returns the data, or #NULL if not found
*/
void*
_dbus_data_slot_list_get (DBusDataSlotAllocator *allocator,
DBusDataSlotList *list,
int slot)
{
#ifndef DBUS_DISABLE_ASSERT
/* We need to take the allocator lock here, because the allocator could
* be e.g. realloc()ing allocated_slots. We avoid doing this if asserts
* are disabled, since then the asserts are empty.
*/
_dbus_rmutex_lock (*(allocator->lock_loc));
_dbus_assert (slot >= 0);
_dbus_assert (slot < allocator->n_allocated_slots);
_dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
_dbus_rmutex_unlock (*(allocator->lock_loc));
#endif
if (slot >= list->n_slots)
return NULL;
else
return list->slots[slot].data;
}
/**
* Frees all data slots contained in the list, calling
* application-provided free functions if they exist.
*
* @param list the list to clear
*/
void
_dbus_data_slot_list_clear (DBusDataSlotList *list)
{
int i;
i = 0;
while (i < list->n_slots)
{
if (list->slots[i].free_data_func)
(* list->slots[i].free_data_func) (list->slots[i].data);
list->slots[i].data = NULL;
list->slots[i].free_data_func = NULL;
++i;
}
}
/**
* Frees the data slot list and all data slots contained
* in it, calling application-provided free functions
* if they exist.
*
* @param list the list to free
*/
void
_dbus_data_slot_list_free (DBusDataSlotList *list)
{
_dbus_data_slot_list_clear (list);
dbus_free (list->slots);
list->slots = NULL;
list->n_slots = 0;
}
/** @} */
#ifdef DBUS_BUILD_TESTS
#include "dbus-test.h"
#include <stdio.h>
static int free_counter;
static void
test_free_slot_data_func (void *data)
{
int i = _DBUS_POINTER_TO_INT (data);
_dbus_assert (free_counter == i);
++free_counter;
}
/**
* Test function for data slots
*/
dbus_bool_t
_dbus_data_slot_test (void)
{
DBusDataSlotAllocator allocator;
DBusDataSlotList list;
int i;
DBusFreeFunction old_free_func;
void *old_data;
DBusRMutex *mutex;
if (!_dbus_data_slot_allocator_init (&allocator))
_dbus_assert_not_reached ("no memory for allocator");
_dbus_data_slot_list_init (&list);
_dbus_rmutex_new_at_location (&mutex);
if (mutex == NULL)
_dbus_assert_not_reached ("failed to alloc mutex");
#define N_SLOTS 100
i = 0;
while (i < N_SLOTS)
{
/* we don't really want apps to rely on this ordered
* allocation, but it simplifies things to rely on it
* here.
*/
dbus_int32_t tmp = -1;
_dbus_data_slot_allocator_alloc (&allocator, &mutex, &tmp);
if (tmp != i)
_dbus_assert_not_reached ("did not allocate slots in numeric order\n");
++i;
}
i = 0;
while (i < N_SLOTS)
{
if (!_dbus_data_slot_list_set (&allocator, &list,
i,
_DBUS_INT_TO_POINTER (i),
test_free_slot_data_func,
&old_free_func, &old_data))
_dbus_assert_not_reached ("no memory to set data");
_dbus_assert (old_free_func == NULL);
_dbus_assert (old_data == NULL);
_dbus_assert (_dbus_data_slot_list_get (&allocator, &list, i) ==
_DBUS_INT_TO_POINTER (i));
++i;
}
free_counter = 0;
i = 0;
while (i < N_SLOTS)
{
if (!_dbus_data_slot_list_set (&allocator, &list,
i,
_DBUS_INT_TO_POINTER (i),
test_free_slot_data_func,
&old_free_func, &old_data))
_dbus_assert_not_reached ("no memory to set data");
_dbus_assert (old_free_func == test_free_slot_data_func);
_dbus_assert (_DBUS_POINTER_TO_INT (old_data) == i);
(* old_free_func) (old_data);
_dbus_assert (i == (free_counter - 1));
_dbus_assert (_dbus_data_slot_list_get (&allocator, &list, i) ==
_DBUS_INT_TO_POINTER (i));
++i;
}
free_counter = 0;
_dbus_data_slot_list_free (&list);
_dbus_assert (N_SLOTS == free_counter);
i = 0;
while (i < N_SLOTS)
{
dbus_int32_t tmp = i;
_dbus_data_slot_allocator_free (&allocator, &tmp);
_dbus_assert (tmp == -1);
++i;
}
_dbus_rmutex_free_at_location (&mutex);
return TRUE;
}
#endif /* DBUS_BUILD_TESTS */