bool Index::check_file_existence(uint32_t dir_hash, uint32_t filename_hash) const
{
auto dir_it = get_hash_table().find(dir_hash);
if (dir_it != get_hash_table().end())
{
return (dir_it->second.find(filename_hash) != dir_it->second.end());
}
return false;
}
const Index::DirHashTable& Index::get_dir_hash_table(uint32_t dir_hash) const
{
auto dir_it = get_hash_table().find(dir_hash);
if (dir_it == get_hash_table().end())
{
throw std::runtime_error("dir_hash not found");
}
else
{
return dir_it->second;
}
}
static int trunc_direct(struct inode * inode)
{
struct super_block * sb;
unsigned int i;
unsigned long * p;
unsigned long block;
struct buffer_head * bh;
int retry = 0;
sb = inode->i_sb;
repeat:
for (i = ((unsigned long) inode->i_size + BLOCK_SIZE-1) / BLOCK_SIZE; i < 10; i++) {
p = inode->u.sysv_i.i_data + i;
block = *p;
if (!block)
continue;
bh = get_hash_table(inode->i_dev,block+sb->sv_block_base,BLOCK_SIZE);
if (i*BLOCK_SIZE < inode->i_size) {
brelse(bh);
goto repeat;
}
if ((bh && bh->b_count != 1) || (block != *p)) {
retry = 1;
brelse(bh);
continue;
}
*p = 0;
inode->i_dirt = 1;
brelse(bh);
sysv_free_block(sb,block);
}
return retry;
}
static int sync_block (struct inode * inode, u32 * block, int wait)
{
struct buffer_head * bh;
int tmp;
if (!*block)
return 0;
tmp = *block;
bh = get_hash_table (inode->i_dev, *block, blocksize);
if (!bh)
return 0;
if (*block != tmp) {
brelse (bh);
return 1;
}
if (wait && buffer_req(bh) && !buffer_uptodate(bh)) {
brelse (bh);
return -1;
}
if (wait || !buffer_uptodate(bh) || !buffer_dirty(bh)) {
brelse (bh);
return 0;
}
ll_rw_block (WRITE, 1, &bh);
bh->b_count--;
return 0;
}
Tcl_DString *tcl_krb5_create_object(Tcl_Interp *interp,
char *type,
ClientData datum)
{
Tcl_HashTable *table;
Tcl_DString *handle;
Tcl_HashEntry *entry;
int entry_created = 0;
if (! (table = get_hash_table(interp, type))) {
return 0;
}
if (! (handle = get_new_handle(interp, type))) {
return 0;
}
if (! (entry = Tcl_CreateHashEntry(table, handle, &entry_created))) {
Tcl_SetResult(interp, "error creating hash entry", TCL_STATIC);
Tcl_DStringFree(handle);
return TCL_ERROR;
}
assert(entry_created);
Tcl_SetHashValue(entry, datum);
return handle;
}
/*
* The functions for minix V1 fs truncation.
*/
static int V1_trunc_direct(register struct inode *inode)
{
unsigned short *p;
register struct buffer_head *bh;
unsigned short tmp;
int i;
int retry = 0;
repeat:
for (i = DIRECT_BLOCK; i < 7; i++) {
p = &inode->i_zone[i];
if (!(tmp = *p))
continue;
bh = get_hash_table(inode->i_dev, (block_t) tmp);
if (i < DIRECT_BLOCK) {
brelse(bh);
goto repeat;
}
if ((bh && bh->b_count != 1) || tmp != *p) {
retry = 1;
brelse(bh);
continue;
}
*p = 0;
inode->i_dirt = 1;
if (bh) {
mark_buffer_clean(bh);
brelse(bh);
}
minix_free_block(inode->i_sb, tmp);
}
return retry;
}
static int V1_trunc_indirect(register struct inode *inode,
int offset, unsigned short *p)
{
struct buffer_head *bh;
int i;
unsigned short tmp;
register struct buffer_head *ind_bh;
unsigned short *ind;
int retry = 0;
tmp = *p;
if (!tmp) return 0;
ind_bh = bread(inode->i_dev, (block_t) tmp);
if (tmp != *p) {
brelse(ind_bh);
return 1;
}
if (!ind_bh) {
*p = 0;
return 0;
}
map_buffer(ind_bh);
repeat:
for (i = INDIRECT_BLOCK(offset); i < 512; i++) {
if (i < 0) i = 0;
else if (i < INDIRECT_BLOCK(offset)) goto repeat;
ind = i + (unsigned short *) ind_bh->b_data;
tmp = *ind;
if (!tmp) continue;
bh = get_hash_table(inode->i_dev, (block_t) tmp);
if (i < INDIRECT_BLOCK(offset)) {
brelse(bh);
goto repeat;
}
if ((bh && bh->b_count != 1) || tmp != *ind) {
retry = 1;
brelse(bh);
continue;
}
*ind = 0;
mark_buffer_dirty(ind_bh, 1);
brelse(bh);
minix_free_block(inode->i_sb, tmp);
}
ind = (unsigned short *) ind_bh->b_data;
for (i = 0; i < 512; i++)
if (*(ind++)) break;
if (i >= 512) {
if (ind_bh->b_count != 1) retry = 1;
else {
tmp = *p;
*p = 0;
minix_free_block(inode->i_sb, tmp);
}
}
unmap_brelse(ind_bh);
return retry;
}
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * bh, * tmp;
int buffers;
repeat:
if (bh = get_hash_table(dev,block))
return bh;
buffers = NR_BUFFERS;
tmp = free_list;
do {
tmp = tmp->b_next_free;
if (tmp->b_count)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
if (tmp->b_dirt)
ll_rw_block(WRITEA,tmp);
/* and repeat until we find something good */
} while (buffers--);
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
/*
* Ok, this is getblk, and it isn't very clear, again to hinder
* race-conditions. Most of the code is seldom used, (ie repeating),
* so it should be much more efficient than it looks.
*/
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp;
repeat:
if ((tmp=get_hash_table(dev,block)))
return tmp;
tmp = free_list;
do {
if (!tmp->b_count) {
wait_on_buffer(tmp); /* we still have to wait */
if (!tmp->b_count) /* on it, it might be dirty */
break;
}
tmp = tmp->b_next_free;
} while (tmp != free_list || (tmp=NULL));
/* Kids, don't try THIS at home ^^^^^. Magic */
if (!tmp) {
printk("Sleeping on free buffer ..");
sleep_on(&buffer_wait);
printk("ok\n");
goto repeat;
}
tmp->b_count++;
remove_from_queues(tmp);
/*
* Now, when we know nobody can get to this node (as it's removed from the
* free list), we write it out. We can sleep here without fear of race-
* conditions.
*/
if (tmp->b_dirt)
sync_dev(tmp->b_dev);
/* update buffer contents */
tmp->b_dev=dev;
tmp->b_blocknr=block;
tmp->b_dirt=0;
tmp->b_uptodate=0;
/* NOTE!! While we possibly slept in sync_dev(), somebody else might have
* added "this" block already, so check for that. Thank God for goto's.
*/
if (find_buffer(dev,block)) {
tmp->b_dev=0; /* ok, someone else has beaten us */
tmp->b_blocknr=0; /* to it - free this block and */
tmp->b_count=0; /* try again */
insert_into_queues(tmp);
goto repeat;
}
/* and then insert into correct position */
insert_into_queues(tmp);
return tmp;
}
/*
* Try-to-share-buffers tries to minimize memory use by trying to keep
* both code pages and the buffer area in the same page. This is done by
* (a) checking if the buffers are already aligned correctly in memory and
* (b) if none of the buffer heads are in memory at all, trying to load
* them into memory the way we want them.
*
* This doesn't guarantee that the memory is shared, but should under most
* circumstances work very well indeed (ie >90% sharing of code pages on
* demand-loadable executables).
*/
static inline unsigned long try_to_share_buffers(unsigned long address,
dev_t dev, int *b, int size)
{
struct buffer_head * bh;
int block;
block = b[0];
if (!block)
return 0;
bh = get_hash_table(dev, block, size);
if (bh)
return check_aligned(bh, address, dev, b, size);
return try_to_load_aligned(address, dev, b, size);
}
void zz_manager::for_each (zz_device_objects_callback callback)
{
zz_hash_table<zz_node*>::iterator it, it_end;
zz_hash_table<zz_node*> * nodes = get_hash_table(); // All children nodes could be accessed via name hash table.
if (!nodes) {
return;
}
//ZZ_LOG("manager: for_each(%x)", nodes);
//ZZ_LOG("(%s)-%d\n", get_name(), nodes->size());
for (it = nodes->begin(), it_end = nodes->end(); it != it_end; ++it) {
callback(*it);
}
}
void ext_free_block(struct super_block * sb, int block)
{
struct buffer_head * bh;
struct ext_free_block * efb;
if (!sb) {
printk("trying to free block on non-existent device\n");
return;
}
lock_super (sb);
if (block < sb->u.ext_sb.s_firstdatazone ||
block >= sb->u.ext_sb.s_nzones) {
printk("trying to free block not in datazone\n");
return;
}
bh = get_hash_table(sb->s_dev, block, sb->s_blocksize);
if (bh)
mark_buffer_clean(bh);
brelse(bh);
if (sb->u.ext_sb.s_firstfreeblock)
efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
if (!sb->u.ext_sb.s_firstfreeblock || efb->count == 254) {
#ifdef EXTFS_DEBUG
printk("ext_free_block: block full, skipping to %d\n", block);
#endif
if (sb->u.ext_sb.s_firstfreeblock)
brelse (sb->u.ext_sb.s_firstfreeblock);
if (!(sb->u.ext_sb.s_firstfreeblock = bread (sb->s_dev,
block, sb->s_blocksize)))
panic ("ext_free_block: unable to read block to free\n");
efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
efb->next = sb->u.ext_sb.s_firstfreeblocknumber;
efb->count = 0;
sb->u.ext_sb.s_firstfreeblocknumber = block;
} else {
efb->free[efb->count++] = block;
}
sb->u.ext_sb.s_freeblockscount ++;
sb->s_dirt = 1;
mark_buffer_dirty(sb->u.ext_sb.s_firstfreeblock, 1);
unlock_super (sb);
return;
}
struct buffer_head *getblk(kdev_t dev, block_t block)
{
register struct buffer_head *bh;
/* If there are too many dirty buffers, we wake up the update process
* now so as to ensure that there are still clean buffers available
* for user processes to use (and dirty) */
do {
bh = get_hash_table(dev, block);
if (bh != NULL) {
if (buffer_clean(bh) && buffer_uptodate(bh))
put_last_lru(bh);
return bh;
}
/* I think the following check is redundant
* So I will remove it for now
*/
} while(find_buffer(dev, block));
/*
* Create a buffer for this job.
*/
bh = get_free_buffer();
/* OK, FINALLY we know that this buffer is the only one of its kind,
* and that it's unused (b_count=0), unlocked (buffer_locked=0), and clean
*/
bh->b_count = 1;
bh->b_dirty = 0;
bh->b_lock = 0;
bh->b_uptodate = 0;
bh->b_dev = dev;
bh->b_blocknr = block;
bh->b_seg = kernel_ds;
return bh;
}
static unsigned long check_aligned(struct buffer_head * first, unsigned long address,
dev_t dev, int *b, int size)
{
struct buffer_head * bh[8];
unsigned long page;
unsigned long offset;
int block;
int nrbuf;
page = (unsigned long) first->b_data;
if (page & ~PAGE_MASK) {
brelse(first);
return 0;
}
mem_map[MAP_NR(page)]++;
bh[0] = first;
nrbuf = 1;
for (offset = size ; offset < PAGE_SIZE ; offset += size) {
block = *++b;
if (!block)
goto no_go;
first = get_hash_table(dev, block, size);
if (!first)
goto no_go;
bh[nrbuf++] = first;
if (page+offset != (unsigned long) first->b_data)
goto no_go;
}
read_buffers(bh,nrbuf); /* make sure they are actually read correctly */
while (nrbuf-- > 0)
brelse(bh[nrbuf]);
free_page(address);
++current->min_flt;
return page;
no_go:
while (nrbuf-- > 0)
brelse(bh[nrbuf]);
free_page(page);
return 0;
}
ClientData tcl_krb5_get_object(Tcl_Interp *interp,
char *handle)
{
char *myhandle, *id_ptr;
Tcl_HashTable *table;
Tcl_HashEntry *entry;
if (! (myhandle = strdup(handle))) {
Tcl_SetResult(interp, memory_error, TCL_STATIC);
return 0;
}
if (! (id_ptr = index(myhandle, *SEP_STR))) {
free(myhandle);
Tcl_ResetResult(interp);
Tcl_AppendResult(interp, "malformatted handle \"", handle,
"\"", 0);
return 0;
}
*id_ptr = '\0';
if (! (table = get_hash_table(interp, myhandle))) {
free(myhandle);
return 0;
}
free(myhandle);
if (! (entry = Tcl_FindHashEntry(table, handle))) {
Tcl_ResetResult(interp);
Tcl_AppendResult(interp, "no object corresponding to handle \"",
handle, "\"", 0);
return 0;
}
return(Tcl_GetHashValue(entry));
}
// unbind object textures to change loading scheme.
// this method will be called to change texture loading quality level.
bool zz_manager_texture::unbind_object_textures ()
{
zz_hash_table<zz_node*>::iterator it, it_end;
zz_hash_table<zz_node*> * nodes = get_hash_table();
zz_texture * tex;
if (!nodes) return true;
for (it = nodes->begin(), it_end = nodes->end(); it != it_end; ++it) {
tex = static_cast<zz_texture*>(*it);
if (tex->get_for_image()) { // no need to unbind sprite image textures as these texture's reloading scheme is not changed
continue;
}
if (tex->get_lock_texture()) // skip if the texture is locked
continue;
tex->unbind_device();
}
return true;
}
void filter_by_id(const char* fn, hash_table* T)
{
fprintf(stderr, "filtering ... \n");
samfile_t* fin = samopen(fn, "rb", NULL);
if (fin == NULL) {
fprintf(stderr, "can't open bam file %s\n", fn);
exit(1);
}
samfile_t* fout = samopen("-", "w", (void*)fin->header);
if (fout == NULL) {
fprintf(stderr, "can't open stdout, for some reason.\n");
exit(1);
}
fputs(fin->header->text, stdout);
bam1_t* b = bam_init1();
uint32_t n = 0;
while (samread(fin, b) >= 0) {
if (++n % 1000000 == 0) {
fprintf(stderr, "\t%d reads\n", n);
}
if (get_hash_table(T, bam1_qname(b), b->core.l_qname) == 1) {
samwrite(fout, b);
}
}
bam_destroy1(b);
samclose(fout);
samclose(fin);
fprintf(stderr, "done.\n");
}
//// 取高速缓冲中指定的缓冲区。
// 检查所指定的缓冲区是否已经在高速缓冲中，如果不在，就需要在高速缓冲中建立一个对应的新项。
// 返回相应缓冲区头指针。
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp, * bh;
repeat:
// 搜索hash 表，如果指定块已经在高速缓冲中，则返回对应缓冲区头指针，退出。
if (bh = get_hash_table(dev,block))
return bh;
// 扫描空闲数据块链表，寻找空闲缓冲区。
// 首先让tmp 指向空闲链表的第一个空闲缓冲区头。
tmp = free_list;
do {
// 如果该缓冲区正被使用（引用计数不等于0），则继续扫描下一项。
if (tmp->b_count)
continue;
// 如果缓冲头指针bh 为空，或者tmp 所指缓冲头的标志(修改、锁定)权重小于bh 头标志的权重，
// 则让bh 指向该tmp 缓冲区头。如果该tmp 缓冲区头表明缓冲区既没有修改也没有锁定标志置位，
// 则说明已为指定设备上的块取得对应的高速缓冲区，则退出循环。
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
/* 重复操作直到找到适合的缓冲区 */
} while ((tmp = tmp->b_next_free) != free_list);
// 如果所有缓冲区都正被使用（所有缓冲区的头部引用计数都>0），
// 则睡眠，等待有空闲的缓冲区可用。
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
// 等待该缓冲区解锁（如果已被上锁的话）。
wait_on_buffer(bh);
// 如果该缓冲区又被其它任务使用的话，只好重复上述过程。
if (bh->b_count)
goto repeat;
// 如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。如果该缓冲区又被其它任务使用
// 的话，只好再重复上述过程。
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* 注意！！当进程为了等待该缓冲块而睡眠时，其它进程可能已经将该缓冲块 */
/* 加入进高速缓冲中，所以要对此进行检查。 */
// 在高速缓冲hash 表中检查指定设备和块的缓冲区是否已经被加入进去。如果是的话，就再次重复
// 上述过程。
if (find_buffer(dev,block))
goto repeat;
/* OK，最终我们知道该缓冲区是指定参数的唯一一块， */
/* 而且还没有被使用(b_count=0)，未被上锁(b_lock=0)，并且是干净的（未被修改的） */
// 于是让我们占用此缓冲区。置引用计数为1，复位修改标志和有效(更新)标志。
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
// 从hash 队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
// 然后根据此新的设备号和块号重新插入空闲链表和hash 队列新位置处。并最终返回缓冲头指针。
insert_into_queues(bh);
return bh;
}
struct buffer_head * getblk(dev_t dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
static int grow_size = 0;
repeat:
bh = get_hash_table(dev, block, size);
if (bh) {
if (bh->b_uptodate && !bh->b_dirt)
put_last_free(bh);
return bh;
}
grow_size -= size;
if (nr_free_pages > min_free_pages && grow_size <= 0) {
if (grow_buffers(GFP_BUFFER, size))
grow_size = PAGE_SIZE;
}
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (mem_map[MAP_NR((unsigned long) tmp->b_data)] != 1)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt) {
tmp->b_count++;
ll_rw_block(WRITEA, 1, &tmp);
tmp->b_count--;
}
#endif
}
if (!bh) {
if (nr_free_pages > 5)
if (grow_buffers(GFP_BUFFER, size))
goto repeat;
if (!grow_buffers(GFP_ATOMIC, size))
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(0,0);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of its kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
bh->b_req=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
struct buffer_head * getblk(int dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
repeat:
if (bh = get_hash_table(dev, block, size))
return bh;
if (nr_free_pages > 30)
grow_buffers(size);
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt)
ll_rw_block(WRITEA,tmp);
#endif
}
if (!bh && nr_free_pages > 5) {
grow_buffers(size);
goto repeat;
}
/* and repeat until we find something good */
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(bh->b_dev);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
static int trunc_indirect(struct inode * inode, unsigned long offset, unsigned long * p, int convert, unsigned char * dirt)
{
unsigned long indtmp, indblock;
struct super_block * sb;
struct buffer_head * indbh;
unsigned int i;
sysv_zone_t * ind;
unsigned long tmp, block;
struct buffer_head * bh;
int retry = 0;
indblock = indtmp = *p;
if (convert)
indblock = from_coh_ulong(indblock);
if (!indblock)
return 0;
sb = inode->i_sb;
indbh = bread(inode->i_dev,indblock+sb->sv_block_base,BLOCK_SIZE);
if (indtmp != *p) {
brelse(indbh);
return 1;
}
if (!indbh) {
*p = 0;
*dirt = 1;
return 0;
}
repeat:
if (inode->i_size < offset)
i = 0;
else
i = (inode->i_size - offset + BLOCK_SIZE-1) / BLOCK_SIZE;
for (; i < IND_PER_BLOCK; i++) {
ind = ((sysv_zone_t *) indbh->b_data) + i;
block = tmp = *ind;
if (sb->sv_convert)
block = from_coh_ulong(block);
if (!block)
continue;
bh = get_hash_table(inode->i_dev,block+sb->sv_block_base,BLOCK_SIZE);
if (i*BLOCK_SIZE + offset < inode->i_size) {
brelse(bh);
goto repeat;
}
if ((bh && bh->b_count != 1) || (tmp != *ind)) {
retry = 1;
brelse(bh);
continue;
}
*ind = 0;
mark_buffer_dirty(indbh, 1);
brelse(bh);
sysv_free_block(sb,block);
}
for (i = 0; i < IND_PER_BLOCK; i++)
if (((sysv_zone_t *) indbh->b_data)[i])
goto done;
if ((indbh->b_count != 1) || (indtmp != *p)) {
brelse(indbh);
return 1;
}
*p = 0;
*dirt = 1;
sysv_free_block(sb,indblock);
done:
brelse(indbh);
return retry;
}
//// 取高速缓冲中指定的缓冲区。
// 检查所指定的缓冲区是否已经在高速缓冲中，如果不在，就需要在高速缓冲中建立一个对应的新项。
// 返回相应缓冲区头指针。
struct buffer_head *
getblk( int dev, int block )
{
struct buffer_head *tmp, *bh;
repeat:
// 搜索hash 表，如果指定块已经在高速缓冲中，则返回对应缓冲区头指针，退出。
if( bh = get_hash_table( dev, block ) )
{
return bh;
}
// 扫描空闲数据块链表，寻找空闲缓冲区。
// 首先让tmp 指向空闲链表的第一个空闲缓冲区头。
tmp = free_list;
do
{
// 如果该缓冲区正被使用（引用计数不等于0），则继续扫描下一项。
if( tmp->b_count )
{
continue;
}
// 如果缓冲头指针bh 为空，或者tmp 所指缓冲头的标志(修改、锁定)权重小于bh 头标志的权重，
// 则让bh 指向该tmp 缓冲区头。如果该tmp 缓冲区头表明缓冲区既没有修改也没有锁定标志置位，
// 则说明已为指定设备上的块取得对应的高速缓冲区，则退出循环。
if( !bh || BADNESS( tmp ) < BADNESS( bh ) )
{
bh = tmp;
if( !BADNESS( tmp ) )
{
break;
}
}
/* and repeat until we find something good *//* 重复操作直到找到适合的缓冲区 */
}
while( ( tmp = tmp->b_next_free ) != free_list );
// 如果所有缓冲区都正被使用（所有缓冲区的头部引用计数都>0），则睡眠，等待有空闲的缓冲区可用。
if( !bh )
{
sleep_on( &buffer_wait );
goto repeat;
}
// 等待该缓冲区解锁（如果已被上锁的话）。
wait_on_buffer( bh );
// 如果该缓冲区又被其它任务使用的话，只好重复上述过程。
if( bh->b_count )
{
goto repeat;
}
// 如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。如果该缓冲区又被其它任务使用
// 的话，只好再重复上述过程。
while( bh->b_dirt )
{
sync_dev( bh->b_dev );
wait_on_buffer( bh );
if( bh->b_count )
{
goto repeat;
}
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
/* 注意！！当进程为了等待该缓冲块而睡眠时，其它进程可能已经将该缓冲块 */
** /
// 在高速缓冲hash 表中检查指定设备和块的缓冲区是否已经被加入进去。如果是的话，就再次重复
// 上述过程。
if( find_buffer( dev, block ) )
{
goto repeat;
}
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
/* OK，最终我们知道该缓冲区是指定参数的唯一一块，*/
/* 而且还没有被使用(b_count=0)，未被上锁(b_lock=0)，并且是干净的（未被修改的）*/
// 于是让我们占用此缓冲区。置引用计数为1，复位修改标志和有效(更新)标志。
bh->b_count = 1;
bh->b_dirt = 0;
bh->b_uptodate = 0;
// 从hash 队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。
remove_from_queues( bh );
bh->b_dev = dev;
bh->b_blocknr = block;
// 然后根据此新的设备号和块号重新插入空闲链表和hash 队列新位置处。并最终返回缓冲头指针。
insert_into_queues( bh );
return bh;
}
struct buffer_head * journal_get_hash_table (struct super_block *s, int block)
{
return get_hash_table (SB_JOURNAL_DEV(s), block, s->s_blocksize );
}
void filter_by_id(const char* fn, hash_table* T)
{
fprintf(stderr, "filtering ... \n");
samfile_t* fin = samopen(fn, "rb", NULL);
if (fin == NULL) {
fprintf(stderr, "can't open bam file %s\n", fn);
exit(1);
}
samfile_t* fout = samopen("-", "w", (void*)fin->header);
if (fout == NULL) {
fprintf(stderr, "can't open stdout, for some reason.\n");
exit(1);
}
fputs(fin->header->text, stdout);
bam1_t* b = bam_init1();
uint32_t n = 0;
char* qname = NULL;
size_t qname_size = 0;
while (samread(fin, b) >= 0) {
if (++n % 1000000 == 0) {
fprintf(stderr, "\t%d reads\n", n);
}
if (qname_size < b->core.l_qname + 3) {
qname_size = b->core.l_qname + 3;
qname = realloc(qname, qname_size);
}
memcpy(qname, bam1_qname(b), b->core.l_qname);
if (b->core.flag & BAM_FREAD2) {
qname[b->core.l_qname] = '/';
qname[b->core.l_qname + 1] = '2';
qname[b->core.l_qname + 2] = '\0';
}
else {
qname[b->core.l_qname] = '/';
qname[b->core.l_qname + 1] = '1';
qname[b->core.l_qname + 2] = '\0';
}
if (get_hash_table(T, qname, b->core.l_qname + 2) == 1) {
samwrite(fout, b);
}
}
free(qname);
bam_destroy1(b);
samclose(fout);
samclose(fin);
fprintf(stderr, "done.\n");
}
bool Index::check_dir_existence(uint32_t dir_hash) const
{
return (get_hash_table().find(dir_hash) != get_hash_table().end());
}
void zz_manager_texture::unbind_notset ()
{
zz_hash_table<zz_node*>::iterator it, it_end;
zz_hash_table<zz_node*> * nodes = get_hash_table();
zz_texture * tex;
if (!nodes) return;
zz_camera * cam = znzin->get_camera();
if (cam) {
if (cam->get_speed() > 0) {
// now, camera is moving, so do not unbind textures
//ZZ_LOG("manager_texture: camera is moving\n");
return;
}
}
unsigned int max_tex_mem = znzin->renderer->get_max_texmem() >> 20; // byte -> megabyte
unsigned int ava_tex_mem = znzin->renderer->get_available_texmem() >> 20;
const unsigned int suff_tex_mem = 20; // sufficient available texture memory 20 MB
#if !defined(UNBIND_ALL)
if (ava_tex_mem > suff_tex_mem) {
if ((ava_tex_mem * 3) > max_tex_mem) {
return;
}
}
#endif
static zz_time s_accum_time = 0; // accumulated time
const zz_time max_accum_time = ZZ_MSEC_TO_TIME(1000); // default 1000 msec
s_accum_time += znzin->get_diff_time();
// we do not unbind in every frame. we do only after some time elapsed
// and the ratio is (ava_tex_mem / max_tex_mem)
if (s_accum_time*max_tex_mem < max_accum_time*ava_tex_mem) // s_accum_time < max_accum_time * (ava_tex_mem / max_tex_mem)
return;
zz_time current_time = znzin->get_current_time();
const zz_time MAX_DIFF_TIME = ZZ_MSEC_TO_TIME(10000); // default 10 second
texlist.clear();
for (it = nodes->begin(), it_end = nodes->end(); it != it_end; ++it) {
tex = static_cast<zz_texture*>(*it);
if (tex->get_lock_texture()) // skip texture that was locked for some reason
continue;
if (tex->get_last_settime() == current_time) // skip if it was used in the current frame
continue;
if (!tex->get_device_updated()) // skip if it was not device-ready
continue;
if (entrance_line.find(tex)) // skip if it is manager-controlled. it will be flushed by manager queue mechanism
continue;
if (exit_line.find(tex)) // skip if it is manager-controlled. it will be flushed by manager queue mechanism
continue;
texlist.push_back(tex); // insert the texture into the texlist
}
if (texlist.empty()) // skip if the texlist is empty
return;
texture_settime_compare texture_cf; // declare texture comparision function
// sort texture list by last_settime
std::sort(texlist.begin(), texlist.end(), texture_cf);
tex = *texlist.begin(); // consider only the first
assert(tex);
// skip if the texture is recently used.
if ((current_time - tex->get_last_settime()) < MAX_DIFF_TIME)
return;
s_accum_time = 0; // intialize accum_time
tex->unbind_device();
tex->update_last_settime();
}
//检查指定（设备号和块号）的缓冲区是否已经在高速缓冲中。如果指定块已经在高速缓冲中，则返回
//对应缓冲区头指针退出；如果不在，就需要在高速缓冲中设置一个对应设备号和块号的新项。返回相应
//缓冲区头指针
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp, * bh;
repeat:
if ( (bh = get_hash_table(dev,block)) )
return bh;
tmp = free_list;
do {
if (tmp->b_count)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
/* and repeat until we find something good */
} while ((tmp = tmp->b_next_free) != free_list);
//如果循环检查所有缓冲块都正在被使用（所有缓冲块的头部引用计数都>0)中，则睡眠等待有空闲
//缓冲块可用。当有空闲块可用时本进程会被明确地唤醒。然后我们就跳转到函数开始处重新查找空闲
//缓冲块
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
//如果跑到这里，说明已经找到一个空闲的缓冲区块。于是先等待该缓冲区解锁（如果已经被上锁的话）。
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
//如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
//当进程为了等待该缓冲块而睡眠时，其他进程可能已经将该缓冲块进入高速缓冲中，因此我们也要对此进行检查
if (find_buffer(dev,block))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
//到了这里，最终我们知道该缓冲块是指定参数的唯一一块，而且目前还没有被占用（b_count=0)
//也没有被上锁(b_lock=0)，而且是干净的(b_dirt=0)
//于是我们占用此缓冲块。置引用计数为1，复位修改标志和有效标志
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
//从hash队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。然后根据
//此新的设备号和块号重新插入空闲链表和hash队列新位置处。并最终返回缓冲头指针。
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
