Aegisub/aegisub/libass/ass_cache.c
Amar Takhar b00e485149 Plug a bunch of memory leaks from uau in the mplayer2 repo: http://repo.or.cz/w/mplayer.git?a=commit;h=312d9e4b104741b834aa5d71b02228d0cd988a4e
libass: Fix cache lookup problem causing memory bloat

The cache code did hash lookups by storing key values in struct fields
and then hashing and comparing the struct as a single memory block. In
at least one case such a struct contained uninitialized padding bytes
which prevented the complete memory area of the struct from matching
even though the fields did. As a result the code failed to find
existing objects in the cache and stored new versions of them, causing
gigabytes of memory use in some circumstances. Initializing the struct
memory to zero before writing the fields avoided such memory use in
tests but is not guaranteed to work if I interpret the C standard
correctly (the compiler is allowed to write garbage over padding bytes
when changing struct member values).

Change the code to use struct-specific hashing and comparison
functions that work field by field to guarantee correct behavior.
Create these by replacing the struct definition with a template that
lists the fields and can be used the generate each of struct
definition, hash function and compare function with some preprocessor
magic (otherwise every field would need to be listed separately in all
three).

Originally committed to SVN as r2895.
2009-05-04 06:48:21 +00:00

386 lines
9 KiB
C

// -*- c-basic-offset: 8; indent-tabs-mode: t -*-
// vim:ts=8:sw=8:noet:ai:
/*
* Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
*
* This file is part of libass.
*
* libass 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.
*
* libass 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 libass; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <inttypes.h>
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H
#include <assert.h>
#include "mputils.h"
#include "ass.h"
#include "ass_fontconfig.h"
#include "ass_font.h"
#include "ass_bitmap.h"
#include "ass_cache.h"
typedef struct hashmap_item_s {
void* key;
void* value;
struct hashmap_item_s* next;
} hashmap_item_t;
typedef hashmap_item_t* hashmap_item_p;
struct hashmap_s {
int nbuckets;
size_t key_size, value_size;
hashmap_item_p* root;
hashmap_item_dtor_t item_dtor; // a destructor for hashmap key/value pairs
hashmap_key_compare_t key_compare;
hashmap_hash_t hash;
// stats
int hit_count;
int miss_count;
int count;
};
#define FNV1_32A_INIT (unsigned)0x811c9dc5
static inline unsigned fnv_32a_buf(void* buf, size_t len, unsigned hval)
{
unsigned char *bp = buf;
unsigned char *be = bp + len;
while (bp < be) {
hval ^= (unsigned)*bp++;
hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
}
return hval;
}
static inline unsigned fnv_32a_str(char* str, unsigned hval)
{
unsigned char* s = (unsigned char*)str;
while (*s) {
hval ^= (unsigned)*s++;
hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
}
return hval;
}
static unsigned hashmap_hash(void* buf, size_t len)
{
return fnv_32a_buf(buf, len, FNV1_32A_INIT);
}
static int hashmap_key_compare(void* a, void* b, size_t size)
{
return memcmp(a, b, size) == 0;
}
static void hashmap_item_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
free(key);
free(value);
}
hashmap_t* hashmap_init(size_t key_size, size_t value_size, int nbuckets,
hashmap_item_dtor_t item_dtor, hashmap_key_compare_t key_compare,
hashmap_hash_t hash)
{
hashmap_t* map = calloc(1, sizeof(hashmap_t));
map->nbuckets = nbuckets;
map->key_size = key_size;
map->value_size = value_size;
map->root = calloc(nbuckets, sizeof(hashmap_item_p));
map->item_dtor = item_dtor ? item_dtor : hashmap_item_dtor;
map->key_compare = key_compare ? key_compare : hashmap_key_compare;
map->hash = hash ? hash : hashmap_hash;
return map;
}
void hashmap_done(hashmap_t* map)
{
int i;
// print stats
if (map->count > 0 || map->hit_count + map->miss_count > 0)
mp_msg(MSGT_ASS, MSGL_V, "cache statistics: \n total accesses: %d\n hits: %d\n misses: %d\n object count: %d\n",
map->hit_count + map->miss_count, map->hit_count, map->miss_count, map->count);
for (i = 0; i < map->nbuckets; ++i) {
hashmap_item_t* item = map->root[i];
while (item) {
hashmap_item_t* next = item->next;
map->item_dtor(item->key, map->key_size, item->value, map->value_size);
free(item);
item = next;
}
}
free(map->root);
free(map);
}
// does nothing if key already exists
void* hashmap_insert(hashmap_t* map, void* key, void* value)
{
unsigned hash = map->hash(key, map->key_size);
hashmap_item_t** next = map->root + (hash % map->nbuckets);
while (*next) {
if (map->key_compare(key, (*next)->key, map->key_size))
return (*next)->value;
next = &((*next)->next);
assert(next);
}
(*next) = malloc(sizeof(hashmap_item_t));
(*next)->key = malloc(map->key_size);
(*next)->value = malloc(map->value_size);
memcpy((*next)->key, key, map->key_size);
memcpy((*next)->value, value, map->value_size);
(*next)->next = 0;
map->count ++;
return (*next)->value;
}
void* hashmap_find(hashmap_t* map, void* key)
{
unsigned hash = map->hash(key, map->key_size);
hashmap_item_t* item = map->root[hash % map->nbuckets];
while (item) {
if (map->key_compare(key, item->key, map->key_size)) {
map->hit_count++;
return item->value;
}
item = item->next;
}
map->miss_count++;
return 0;
}
//---------------------------------
// font cache
hashmap_t* font_cache;
static unsigned font_desc_hash(void* buf, size_t len)
{
ass_font_desc_t* desc = buf;
unsigned hval;
hval = fnv_32a_str(desc->family, FNV1_32A_INIT);
hval = fnv_32a_buf(&desc->bold, sizeof(desc->bold), hval);
hval = fnv_32a_buf(&desc->italic, sizeof(desc->italic), hval);
return hval;
}
static int font_compare(void* key1, void* key2, size_t key_size) {
ass_font_desc_t* a = key1;
ass_font_desc_t* b = key2;
if (strcmp(a->family, b->family) != 0)
return 0;
if (a->bold != b->bold)
return 0;
if (a->italic != b->italic)
return 0;
if (a->treat_family_as_pattern != b->treat_family_as_pattern)
return 0;
return 1;
}
static void font_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
ass_font_free(value);
free(key);
}
ass_font_t* ass_font_cache_find(ass_font_desc_t* desc)
{
return hashmap_find(font_cache, desc);
}
/**
* \brief Add a face struct to cache.
* \param font font struct
*/
void* ass_font_cache_add(ass_font_t* font)
{
return hashmap_insert(font_cache, &(font->desc), font);
}
void ass_font_cache_init(void)
{
font_cache = hashmap_init(sizeof(ass_font_desc_t),
sizeof(ass_font_t),
1000,
font_hash_dtor, font_compare, font_desc_hash);
}
void ass_font_cache_done(void)
{
hashmap_done(font_cache);
}
// Create hash/compare functions for bitmap and glyph
#define CREATE_HASH_FUNCTIONS
#include "ass_cache_template.c"
#define CREATE_COMPARISON_FUNCTIONS
#include "ass_cache_template.c"
//---------------------------------
// bitmap cache
hashmap_t* bitmap_cache;
static void bitmap_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
bitmap_hash_val_t* v = value;
if (v->bm) ass_free_bitmap(v->bm);
if (v->bm_o) ass_free_bitmap(v->bm_o);
if (v->bm_s) ass_free_bitmap(v->bm_s);
free(key);
free(value);
}
void* cache_add_bitmap(bitmap_hash_key_t* key, bitmap_hash_val_t* val)
{
return hashmap_insert(bitmap_cache, key, val);
}
/**
* \brief Get a bitmap from bitmap cache.
* \param key hash key
* \return requested hash val or 0 if not found
*/
bitmap_hash_val_t* cache_find_bitmap(bitmap_hash_key_t* key)
{
return hashmap_find(bitmap_cache, key);
}
void ass_bitmap_cache_init(void)
{
bitmap_cache = hashmap_init(sizeof(bitmap_hash_key_t),
sizeof(bitmap_hash_val_t),
0xFFFF + 13,
bitmap_hash_dtor, bitmap_compare,
bitmap_hash);
}
void ass_bitmap_cache_done(void)
{
hashmap_done(bitmap_cache);
}
void ass_bitmap_cache_reset(void)
{
ass_bitmap_cache_done();
ass_bitmap_cache_init();
}
//---------------------------------
// glyph cache
hashmap_t* glyph_cache;
static void glyph_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
glyph_hash_val_t* v = value;
if (v->glyph) FT_Done_Glyph(v->glyph);
if (v->outline_glyph) FT_Done_Glyph(v->outline_glyph);
free(key);
free(value);
}
void* cache_add_glyph(glyph_hash_key_t* key, glyph_hash_val_t* val)
{
return hashmap_insert(glyph_cache, key, val);
}
/**
* \brief Get a glyph from glyph cache.
* \param key hash key
* \return requested hash val or 0 if not found
*/
glyph_hash_val_t* cache_find_glyph(glyph_hash_key_t* key)
{
return hashmap_find(glyph_cache, key);
}
void ass_glyph_cache_init(void)
{
glyph_cache = hashmap_init(sizeof(glyph_hash_key_t),
sizeof(glyph_hash_val_t),
0xFFFF + 13,
glyph_hash_dtor, glyph_compare, glyph_hash);
}
void ass_glyph_cache_done(void)
{
hashmap_done(glyph_cache);
}
void ass_glyph_cache_reset(void)
{
ass_glyph_cache_done();
ass_glyph_cache_init();
}
//---------------------------------
// composite cache
hashmap_t* composite_cache;
static void composite_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
composite_hash_val_t* v = value;
free(v->a);
free(v->b);
free(key);
free(value);
}
void* cache_add_composite(composite_hash_key_t* key, composite_hash_val_t* val)
{
return hashmap_insert(composite_cache, key, val);
}
/**
* \brief Get a composite bitmap from composite cache.
* \param key hash key
* \return requested hash val or 0 if not found
*/
composite_hash_val_t* cache_find_composite(composite_hash_key_t* key)
{
return hashmap_find(composite_cache, key);
}
void ass_composite_cache_init(void)
{
composite_cache = hashmap_init(sizeof(composite_hash_key_t),
sizeof(composite_hash_val_t),
0xFFFF + 13,
composite_hash_dtor, NULL, NULL);
}
void ass_composite_cache_done(void)
{
hashmap_done(composite_cache);
}
void ass_composite_cache_reset(void)
{
ass_composite_cache_done();
ass_composite_cache_init();
}