harfbuzz/src/hb-blob.c

357 lines
8.0 KiB
C

/*
* Copyright (C) 2009 Red Hat, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Red Hat Author(s): Behdad Esfahbod
*/
#include "hb-private.h"
#include "hb-blob-private.h"
#ifdef HAVE_SYS_MMAN_H
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <sys/mman.h>
#endif /* HAVE_SYS_MMAN_H */
#ifndef HB_DEBUG_BLOB
#define HB_DEBUG_BLOB HB_DEBUG+0
#endif
#include <stdio.h>
#include <errno.h>
hb_blob_t _hb_blob_nil = {
HB_REFERENCE_COUNT_INVALID, /* ref_count */
0, /* length */
HB_MUTEX_INIT, /* lock */
0, /* lock_count */
HB_MEMORY_MODE_READONLY, /* mode */
NULL, /* data */
NULL, /* destroy */
NULL /* user_data */
};
static void
_hb_blob_destroy_user_data (hb_blob_t *blob)
{
if (blob->destroy) {
blob->destroy (blob->user_data);
blob->destroy = NULL;
blob->user_data = NULL;
}
}
static void
_hb_blob_unlock_and_destroy (hb_blob_t *blob)
{
hb_blob_unlock (blob);
hb_blob_destroy (blob);
}
hb_blob_t *
hb_blob_create (const char *data,
unsigned int length,
hb_memory_mode_t mode,
hb_destroy_func_t destroy,
void *user_data)
{
hb_blob_t *blob;
if (!length || !HB_OBJECT_DO_CREATE (hb_blob_t, blob)) {
if (destroy)
destroy (user_data);
return &_hb_blob_nil;
}
hb_mutex_init (blob->lock);
blob->lock_count = 0;
blob->data = data;
blob->length = length;
blob->mode = mode;
blob->destroy = destroy;
blob->user_data = user_data;
if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
blob->mode = HB_MEMORY_MODE_READONLY;
if (!hb_blob_try_writable (blob)) {
hb_blob_destroy (blob);
return &_hb_blob_nil;
}
}
return blob;
}
hb_blob_t *
hb_blob_create_sub_blob (hb_blob_t *parent,
unsigned int offset,
unsigned int length)
{
hb_blob_t *blob;
const char *pdata;
if (!length || offset >= parent->length || !HB_OBJECT_DO_CREATE (hb_blob_t, blob))
return &_hb_blob_nil;
pdata = hb_blob_lock (parent);
blob->data = pdata + offset;
blob->length = MIN (length, parent->length - offset);
hb_mutex_lock (parent->lock);
blob->mode = parent->mode;
hb_mutex_unlock (parent->lock);
blob->destroy = (hb_destroy_func_t) _hb_blob_unlock_and_destroy;
blob->user_data = hb_blob_reference (parent);
return blob;
}
hb_blob_t *
hb_blob_create_empty (void)
{
return &_hb_blob_nil;
}
hb_blob_t *
hb_blob_reference (hb_blob_t *blob)
{
HB_OBJECT_DO_REFERENCE (blob);
}
unsigned int
hb_blob_get_reference_count (hb_blob_t *blob)
{
HB_OBJECT_DO_GET_REFERENCE_COUNT (blob);
}
void
hb_blob_destroy (hb_blob_t *blob)
{
HB_OBJECT_DO_DESTROY (blob);
_hb_blob_destroy_user_data (blob);
free (blob);
}
unsigned int
hb_blob_get_length (hb_blob_t *blob)
{
return blob->length;
}
const char *
hb_blob_lock (hb_blob_t *blob)
{
if (HB_OBJECT_IS_INERT (blob))
return NULL;
hb_mutex_lock (blob->lock);
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s (%d) -> %p\n", blob, __FUNCTION__,
blob->lock_count, blob->data);
blob->lock_count++;
hb_mutex_unlock (blob->lock);
return blob->data;
}
void
hb_blob_unlock (hb_blob_t *blob)
{
if (HB_OBJECT_IS_INERT (blob))
return;
hb_mutex_lock (blob->lock);
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s (%d) -> %p\n", blob, __FUNCTION__,
blob->lock_count, blob->data);
assert (blob->lock_count > 0);
blob->lock_count--;
hb_mutex_unlock (blob->lock);
}
hb_bool_t
hb_blob_is_writable (hb_blob_t *blob)
{
hb_memory_mode_t mode;
if (HB_OBJECT_IS_INERT (blob))
return FALSE;
hb_mutex_lock (blob->lock);
mode = blob->mode;
hb_mutex_unlock (blob->lock);
return mode == HB_MEMORY_MODE_WRITABLE;
}
static hb_bool_t
_try_make_writable_inplace_unix_locked (hb_blob_t *blob)
{
#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
uintptr_t pagesize = -1, mask, length;
const char *addr;
#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
#elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
#elif defined(HAVE_GETPAGESIZE)
pagesize = (uintptr_t) getpagesize ();
#endif
if ((uintptr_t) -1L == pagesize) {
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: failed to get pagesize: %s\n", blob, __FUNCTION__, strerror (errno));
return FALSE;
}
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: pagesize is %u\n", blob, __FUNCTION__, pagesize);
mask = ~(pagesize-1);
addr = (const char *) (((uintptr_t) blob->data) & mask);
length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: calling mprotect on [%p..%p] (%d bytes)\n",
blob, __FUNCTION__,
addr, addr+length, length);
if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: %s\n", blob, __FUNCTION__, strerror (errno));
return FALSE;
}
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: successfully made [%p..%p] (%d bytes) writable\n",
blob, __FUNCTION__,
addr, addr+length, length);
return TRUE;
#else
return FALSE;
#endif
}
static void
_try_writable_inplace_locked (hb_blob_t *blob)
{
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: making writable\n", blob, __FUNCTION__);
if (_try_make_writable_inplace_unix_locked (blob)) {
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: making writable -> succeeded\n", blob, __FUNCTION__);
blob->mode = HB_MEMORY_MODE_WRITABLE;
} else {
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: making writable -> FAILED\n", blob, __FUNCTION__);
/* Failed to make writable inplace, mark that */
blob->mode = HB_MEMORY_MODE_READONLY;
}
}
hb_bool_t
hb_blob_try_writable_inplace (hb_blob_t *blob)
{
hb_memory_mode_t mode;
if (HB_OBJECT_IS_INERT (blob))
return FALSE;
hb_mutex_lock (blob->lock);
if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE)
_try_writable_inplace_locked (blob);
mode = blob->mode;
hb_mutex_unlock (blob->lock);
return mode == HB_MEMORY_MODE_WRITABLE;
}
hb_bool_t
hb_blob_try_writable (hb_blob_t *blob)
{
hb_memory_mode_t mode;
if (HB_OBJECT_IS_INERT (blob))
return FALSE;
hb_mutex_lock (blob->lock);
if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE)
_try_writable_inplace_locked (blob);
if (blob->mode == HB_MEMORY_MODE_READONLY)
{
char *new_data;
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s (%d) -> %p\n", blob, __FUNCTION__,
blob->lock_count, blob->data);
if (blob->lock_count)
goto done;
new_data = malloc (blob->length);
if (new_data) {
if (HB_DEBUG_BLOB)
fprintf (stderr, "%p %s: dupped successfully -> %p\n", blob, __FUNCTION__, blob->data);
memcpy (new_data, blob->data, blob->length);
_hb_blob_destroy_user_data (blob);
blob->mode = HB_MEMORY_MODE_WRITABLE;
blob->data = new_data;
blob->destroy = free;
blob->user_data = new_data;
}
}
done:
mode = blob->mode;
hb_mutex_unlock (blob->lock);
return mode == HB_MEMORY_MODE_WRITABLE;
}