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bolt/db.go

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package bolt
const (
NoSync = iota
NoMetaSync
DupSort
IntegerKey
IntegerDupKey
)
var DatabaseAlreadyOpenedError = &Error{"Database already open"}
// TODO: #define MDB_FATAL_ERROR 0x80000000U /** Failed to update the meta page. Probably an I/O error. */
// TODO: #define MDB_ENV_ACTIVE 0x20000000U /** Some fields are initialized. */
// TODO: #define MDB_ENV_TXKEY 0x10000000U /** me_txkey is set */
// TODO: #define MDB_LIVE_READER 0x08000000U /** Have liveness lock in reader table */
type DB interface {
syncEnabled bool
metaSyncEnabled bool
}
type db struct {
sync.Mutex
opened bool
file os.File
metafile os.File
buf []byte
pageSize int
readers []*reader
buckets []*bucket
xbuckets []*bucketx /**< array of static DB info */
bucketFlags []int /**< array of flags from MDB_db.md_flags */
path string
mmap []byte
mmapSize int /**< size of the data memory map */
size int /**< current file size */
meta1 []byte
meta2 []byte
pbuf []byte
transaction *transaction /**< current write transaction */
maxPageNumber int /**< me_mapsize / me_psize */
pageState pageStage /**< state of old pages from freeDB */
dpages []*page /**< list of malloc'd blocks for re-use */
freePages []int /** IDL of pages that became unused in a write txn */
dirtyPages []int /** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
maxFreeOnePage int /** Max number of freelist items that can fit in a single overflow page */
maxNodeSize int /** Max size of a node on a page */
maxKeySize int /**< max size of a key */
}
func NewDB() DB {
return &db{}
}
func (db *db) Path() string {
return db.path
}
func (db *db) Open(path string, mode os.FileMode) error {
var err error
db.Lock()
defer db.Unlock()
// Exit if the database is currently open.
if db.opened {
return DatabaseAlreadyOpenedError
}
// Open data file and separate sync handler for metadata writes.
db.path = path
if db.file, err = os.OpenFile(db.path, O_RDWR | O_CREAT, mode); err != nil {
db.close()
return err
}
if db.metafile, err = os.OpenFile(db.path, O_RDWR | O_SYNC, mode); err != nil {
db.close()
return err
}
// Read enough data to get both meta pages.
var m, m0, m1 *meta
var buf [headerSize + unsafe.Sizeof(meta)]byte
if _, err := db.file.ReadAt(buf, 0); err == nil {
if m0, _ = db.page(buf[:], 0).meta(); m0 != nil {
db.pageSize = m0.free.pad
}
}
if _, err := db.file.ReadAt(buf, db.pageSize); err == nil {
m1, _ = db.page(buf[:], 0).meta()
}
if m0 != nil && m1 != nil {
if m0.txnid > m1.txnid {
m = m0
} else {
m = m1
}
}
// Initialize the page size for new environments.
if m == nil {
db.pageSize = os.Getpagesize()
if db.pageSize > maxPageSize {
db.pageSize = maxPageSize
}
}
// TODO: Check mapsize.
/*
// Was a mapsize configured?
if (!env->me_mapsize) {
// If this is a new environment, take the default,
// else use the size recorded in the existing env.
env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
} else if (env->me_mapsize < meta.mm_mapsize) {
// If the configured size is smaller, make sure it's
// still big enough. Silently round up to minimum if not.
size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
if (env->me_mapsize < minsize)
env->me_mapsize = minsize;
}
*/
// Memory map the data file.
if err := db.mmap(); err != nil {
db.close()
return err
}
// Initialize the buffer.
db.buf = make([]byte, db.pageSize)
// Mark the database as opened and return.
db.opened = true
return nil
}
// Read the meta pages and return the latest.
func (db *db) readMeta() *meta {
m := &meta{}
m.read()
/*
if ((i = mdb_env_read_header(env, &meta)) != 0) {
if (i != ENOENT)
return i;
DPUTS("new mdbenv");
newenv = 1;
env->me_psize = env->me_os_psize;
if (env->me_psize > MAX_PAGESIZE)
env->me_psize = MAX_PAGESIZE;
} else {
env->me_psize = meta.mm_psize;
}
rc = mdb_env_map(env, meta.mm_address, newenv);
if (rc)
return rc;
if (newenv) {
if (flags & MDB_FIXEDMAP)
meta.mm_address = env->me_map;
i = mdb_env_init_meta(env, &meta);
if (i != MDB_SUCCESS) {
return i;
}
}
env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)
- sizeof(indx_t);
#if !(MDB_MAXKEYSIZE)
env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));
#endif
env->me_maxpg = env->me_mapsize / env->me_psize;
#if MDB_DEBUG
{
int toggle = mdb_env_pick_meta(env);
MDB_db *db = &env->me_metas[toggle]->mm_dbs[MAIN_DBI];
DPRINTF(("opened database version %u, pagesize %u",
env->me_metas[0]->mm_version, env->me_psize));
DPRINTF(("using meta page %d", toggle));
DPRINTF(("depth: %u", db->md_depth));
DPRINTF(("entries: %"Z"u", db->md_entries));
DPRINTF(("branch pages: %"Z"u", db->md_branch_pages));
DPRINTF(("leaf pages: %"Z"u", db->md_leaf_pages));
DPRINTF(("overflow pages: %"Z"u", db->md_overflow_pages));
DPRINTF(("root: %"Z"u", db->md_root));
}
#endif
return MDB_SUCCESS;
*/
return nil
}
// page retrieves a page reference from a given byte array based on the current page size.
func (db *db) page(b []byte, id int) *page {
return (*page)(unsafe.Pointer(b[id * db.pageSize]))
}
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ CONVERTED ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ //
func (db *db) freePage(p *page) {
/*
mp->mp_next = env->me_dpages;
VGMEMP_FREE(env, mp);
env->me_dpages = mp;
*/
}
func (db *db) freeDirtyPage(p *page) {
/*
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
mdb_page_free(env, dp);
} else {
// large pages just get freed directly
VGMEMP_FREE(env, dp);
free(dp);
}
*/
}
func (db *db) freeAllDirtyPages(p *page) {
/*
MDB_env *env = txn->mt_env;
MDB_ID2L dl = txn->mt_u.dirty_list;
unsigned i, n = dl[0].mid;
for (i = 1; i <= n; i++) {
mdb_dpage_free(env, dl[i].mptr);
}
dl[0].mid = 0;
*/
}
func (db *db) sync(force bool) error {
/*
int rc = 0;
if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
if (env->me_flags & MDB_WRITEMAP) {
int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
? MS_ASYNC : MS_SYNC;
if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
rc = ErrCode();
#ifdef _WIN32
else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
#endif
} else {
if (MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
}
}
return rc;
*/
return nil
}
func (db *db) Transaction(parent *transaction, flags int) (*transaction, error) {
/*
MDB_txn *txn;
MDB_ntxn *ntxn;
int rc, size, tsize = sizeof(MDB_txn);
if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
if ((env->me_flags & MDB_RDONLY) && !(flags & MDB_RDONLY))
return EACCES;
if (parent) {
// Nested transactions: Max 1 child, write txns only, no writemap
if (parent->mt_child ||
(flags & MDB_RDONLY) ||
(parent->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR)) ||
(env->me_flags & MDB_WRITEMAP))
{
return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
}
tsize = sizeof(MDB_ntxn);
}
size = tsize + env->me_maxdbs * (sizeof(MDB_db)+1);
if (!(flags & MDB_RDONLY))
size += env->me_maxdbs * sizeof(MDB_cursor *);
if ((txn = calloc(1, size)) == NULL) {
DPRINTF(("calloc: %s", strerror(ErrCode())));
return ENOMEM;
}
txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
if (flags & MDB_RDONLY) {
txn->mt_flags |= MDB_TXN_RDONLY;
txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
} else {
txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
}
txn->mt_env = env;
if (parent) {
unsigned int i;
txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
if (!txn->mt_u.dirty_list ||
!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
{
free(txn->mt_u.dirty_list);
free(txn);
return ENOMEM;
}
txn->mt_txnid = parent->mt_txnid;
txn->mt_dirty_room = parent->mt_dirty_room;
txn->mt_u.dirty_list[0].mid = 0;
txn->mt_spill_pgs = NULL;
txn->mt_next_pgno = parent->mt_next_pgno;
parent->mt_child = txn;
txn->mt_parent = parent;
txn->mt_numdbs = parent->mt_numdbs;
txn->mt_flags = parent->mt_flags;
txn->mt_dbxs = parent->mt_dbxs;
memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
// Copy parent's mt_dbflags, but clear DB_NEW
for (i=0; i<txn->mt_numdbs; i++)
txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
rc = 0;
ntxn = (MDB_ntxn *)txn;
ntxn->mnt_pgstate = env->me_pgstate; // save parent me_pghead & co
if (env->me_pghead) {
size = MDB_IDL_SIZEOF(env->me_pghead);
env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
if (env->me_pghead)
memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
else
rc = ENOMEM;
}
if (!rc)
rc = mdb_cursor_shadow(parent, txn);
if (rc)
mdb_txn_reset0(txn, "beginchild-fail");
} else {
rc = mdb_txn_renew0(txn);
}
if (rc)
free(txn);
else {
*ret = txn;
DPRINTF(("begin txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
}
return rc;
*/
return nil
}
// Write the environment parameters of a freshly created DB environment.
// @param[in] env the environment handle
// @param[out] meta address of where to store the meta information
// @return 0 on success, non-zero on failure.
func (db *db) initMeta(meta *meta) error {
/*
MDB_page *p, *q;
int rc;
unsigned int psize;
#ifdef _WIN32
DWORD len;
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
#define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
ov.Offset = pos; \
rc = WriteFile(fd, ptr, size, &len, &ov); } while(0)
#else
int len;
#define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
len = pwrite(fd, ptr, size, pos); \
rc = (len >= 0); } while(0)
#endif
DPUTS("writing new meta page");
psize = env->me_psize;
meta->mm_magic = MDB_MAGIC;
meta->mm_version = MDB_DATA_VERSION;
meta->mm_mapsize = env->me_mapsize;
meta->mm_psize = psize;
meta->mm_last_pg = 1;
meta->mm_flags = env->me_flags & 0xffff;
meta->mm_flags |= MDB_INTEGERKEY;
meta->mm_dbs[0].md_root = P_INVALID;
meta->mm_dbs[1].md_root = P_INVALID;
p = calloc(2, psize);
p->mp_pgno = 0;
p->mp_flags = P_META;
*(MDB_meta *)METADATA(p) = *meta;
q = (MDB_page *)((char *)p + psize);
q->mp_pgno = 1;
q->mp_flags = P_META;
*(MDB_meta *)METADATA(q) = *meta;
DO_PWRITE(rc, env->me_fd, p, psize * 2, len, 0);
if (!rc)
rc = ErrCode();
else if ((unsigned) len == psize * 2)
rc = MDB_SUCCESS;
else
rc = ENOSPC;
free(p);
return rc;
*/
return nil
}
// Check both meta pages to see which one is newer.
// @param[in] env the environment handle
// @return meta toggle (0 or 1).
func (db *db) pickMeta() int {
/*
return (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid);
*/
return 0
}
func (db *db) Create() error {
/*
MDB_env *e;
e = calloc(1, sizeof(MDB_env));
if (!e)
return ENOMEM;
e->me_maxreaders = DEFAULT_READERS;
e->me_maxdbs = e->me_numdbs = 2;
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
#ifdef MDB_USE_POSIX_SEM
e->me_rmutex = SEM_FAILED;
e->me_wmutex = SEM_FAILED;
#endif
e->me_pid = getpid();
GET_PAGESIZE(e->me_os_psize);
VGMEMP_CREATE(e,0,0);
*env = e;
return MDB_SUCCESS;
*/
return nil
}
// int mdb_env_map(MDB_env *env, void *addr, int newsize)
func (db *db) mmap(newsize int) error {
/*
MDB_page *p;
unsigned int flags = env->me_flags;
#ifdef _WIN32
int rc;
HANDLE mh;
LONG sizelo, sizehi;
sizelo = env->me_mapsize & 0xffffffff;
sizehi = env->me_mapsize >> 16 >> 16; // only needed on Win64
// Windows won't create mappings for zero length files.
// Just allocate the maxsize right now.
if (newsize) {
if (SetFilePointer(env->me_fd, sizelo, &sizehi, 0) != (DWORD)sizelo
|| !SetEndOfFile(env->me_fd)
|| SetFilePointer(env->me_fd, 0, NULL, 0) != 0)
return ErrCode();
}
mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
PAGE_READWRITE : PAGE_READONLY,
sizehi, sizelo, NULL);
if (!mh)
return ErrCode();
env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
FILE_MAP_WRITE : FILE_MAP_READ,
0, 0, env->me_mapsize, addr);
rc = env->me_map ? 0 : ErrCode();
CloseHandle(mh);
if (rc)
return rc;
#else
int prot = PROT_READ;
if (flags & MDB_WRITEMAP) {
prot |= PROT_WRITE;
if (ftruncate(env->me_fd, env->me_mapsize) < 0)
return ErrCode();
}
env->me_map = mmap(addr, env->me_mapsize, prot, MAP_SHARED,
env->me_fd, 0);
if (env->me_map == MAP_FAILED) {
env->me_map = NULL;
return ErrCode();
}
if (flags & MDB_NORDAHEAD) {
// Turn off readahead. It's harmful when the DB is larger than RAM.
#ifdef MADV_RANDOM
madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
#else
#ifdef POSIX_MADV_RANDOM
posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
#endif // POSIX_MADV_RANDOM
#endif // MADV_RANDOM
}
#endif // _WIN32
// Can happen because the address argument to mmap() is just a
// hint. mmap() can pick another, e.g. if the range is in use.
// The MAP_FIXED flag would prevent that, but then mmap could
// instead unmap existing pages to make room for the new map.
if (addr && env->me_map != addr)
return EBUSY; // TODO: Make a new MDB_* error code?
p = (MDB_page *)env->me_map;
env->me_metas[0] = METADATA(p);
env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
return MDB_SUCCESS;
*/
return nil
}
func (db *db) setMapSize(size int) error {
/*
// If env is already open, caller is responsible for making
// sure there are no active txns.
if (env->me_map) {
int rc;
void *old;
if (env->me_txn)
return EINVAL;
if (!size)
size = env->me_metas[mdb_env_pick_meta(env)]->mm_mapsize;
else if (size < env->me_mapsize) {
// If the configured size is smaller, make sure it's
// still big enough. Silently round up to minimum if not.
size_t minsize = (env->me_metas[mdb_env_pick_meta(env)]->mm_last_pg + 1) * env->me_psize;
if (size < minsize)
size = minsize;
}
munmap(env->me_map, env->me_mapsize);
env->me_mapsize = size;
old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
rc = mdb_env_map(env, old, 1);
if (rc)
return rc;
}
env->me_mapsize = size;
if (env->me_psize)
env->me_maxpg = env->me_mapsize / env->me_psize;
return MDB_SUCCESS;
*/
return nil
}
func (db *db) setMaxBucketCount(count int) error {
/*
if (env->me_map)
return EINVAL;
env->me_maxdbs = dbs + 2; // Named databases + main and free DB
return MDB_SUCCESS;
*/
return nil
}
func (db *db) setMaxReaderCount(count int) error {
/*
if (env->me_map || readers < 1)
return EINVAL;
env->me_maxreaders = readers;
return MDB_SUCCESS;
*/
}
func (db *db) getMaxReaderCount(count int) (int, error) {
/*
if (!env || !readers)
return EINVAL;
*readers = env->me_maxreaders;
return MDB_SUCCESS;
*/
return 0, nil
}
// Destroy resources from mdb_env_open(), clear our readers & DBIs
func (db *db) close0(excl) {
/*
int i;
if (!(env->me_flags & MDB_ENV_ACTIVE))
return;
// Doing this here since me_dbxs may not exist during mdb_env_close
for (i = env->me_maxdbs; --i > MAIN_DBI; )
free(env->me_dbxs[i].md_name.mv_data);
free(env->me_pbuf);
free(env->me_dbflags);
free(env->me_dbxs);
free(env->me_path);
free(env->me_dirty_list);
mdb_midl_free(env->me_free_pgs);
if (env->me_flags & MDB_ENV_TXKEY) {
pthread_key_delete(env->me_txkey);
#ifdef _WIN32
// Delete our key from the global list
for (i=0; i<mdb_tls_nkeys; i++)
if (mdb_tls_keys[i] == env->me_txkey) {
mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
mdb_tls_nkeys--;
break;
}
#endif
}
if (env->me_map) {
munmap(env->me_map, env->me_mapsize);
}
if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
(void) close(env->me_mfd);
if (env->me_fd != INVALID_HANDLE_VALUE)
(void) close(env->me_fd);
if (env->me_txns) {
MDB_PID_T pid = env->me_pid;
// Clearing readers is done in this function because
// me_txkey with its destructor must be disabled first.
for (i = env->me_numreaders; --i >= 0; )
if (env->me_txns->mti_readers[i].mr_pid == pid)
env->me_txns->mti_readers[i].mr_pid = 0;
#ifdef _WIN32
if (env->me_rmutex) {
CloseHandle(env->me_rmutex);
if (env->me_wmutex) CloseHandle(env->me_wmutex);
}
// Windows automatically destroys the mutexes when
// the last handle closes.
#elif defined(MDB_USE_POSIX_SEM)
if (env->me_rmutex != SEM_FAILED) {
sem_close(env->me_rmutex);
if (env->me_wmutex != SEM_FAILED)
sem_close(env->me_wmutex);
// If we have the filelock: If we are the
// only remaining user, clean up semaphores.
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0) {
sem_unlink(env->me_txns->mti_rmname);
sem_unlink(env->me_txns->mti_wmname);
}
}
#endif
munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
}
if (env->me_lfd != INVALID_HANDLE_VALUE) {
#ifdef _WIN32
if (excl >= 0) {
// Unlock the lockfile. Windows would have unlocked it
// after closing anyway, but not necessarily at once.
UnlockFile(env->me_lfd, 0, 0, 1, 0);
}
#endif
(void) close(env->me_lfd);
}
env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
*/
}
func (db *db) copyfd(handle int) error {
/*
MDB_txn *txn = NULL;
int rc;
size_t wsize;
char *ptr;
#ifdef _WIN32
DWORD len, w2;
#define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
#else
ssize_t len;
size_t w2;
#define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
#endif
// Do the lock/unlock of the reader mutex before starting the
// write txn. Otherwise other read txns could block writers.
rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
if (rc)
return rc;
if (env->me_txns) {
// We must start the actual read txn after blocking writers
mdb_txn_reset0(txn, "reset-stage1");
// Temporarily block writers until we snapshot the meta pages
LOCK_MUTEX_W(env);
rc = mdb_txn_renew0(txn);
if (rc) {
UNLOCK_MUTEX_W(env);
goto leave;
}
}
wsize = env->me_psize * 2;
ptr = env->me_map;
w2 = wsize;
while (w2 > 0) {
DO_WRITE(rc, fd, ptr, w2, len);
if (!rc) {
rc = ErrCode();
break;
} else if (len > 0) {
rc = MDB_SUCCESS;
ptr += len;
w2 -= len;
continue;
} else {
// Non-blocking or async handles are not supported
rc = EIO;
break;
}
}
if (env->me_txns)
UNLOCK_MUTEX_W(env);
if (rc)
goto leave;
wsize = txn->mt_next_pgno * env->me_psize - wsize;
while (wsize > 0) {
if (wsize > MAX_WRITE)
w2 = MAX_WRITE;
else
w2 = wsize;
DO_WRITE(rc, fd, ptr, w2, len);
if (!rc) {
rc = ErrCode();
break;
} else if (len > 0) {
rc = MDB_SUCCESS;
ptr += len;
wsize -= len;
continue;
} else {
rc = EIO;
break;
}
}
leave:
mdb_txn_abort(txn);
return rc;
}
int
mdb_env_copy(MDB_env *env, const char *path)
{
int rc, len;
char *lpath;
HANDLE newfd = INVALID_HANDLE_VALUE;
if (env->me_flags & MDB_NOSUBDIR) {
lpath = (char *)path;
} else {
len = strlen(path);
len += sizeof(DATANAME);
lpath = malloc(len);
if (!lpath)
return ENOMEM;
sprintf(lpath, "%s" DATANAME, path);
}
// The destination path must exist, but the destination file must not.
// We don't want the OS to cache the writes, since the source data is
// already in the OS cache.
#ifdef _WIN32
newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
#else
newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL, 0666);
#endif
if (newfd == INVALID_HANDLE_VALUE) {
rc = ErrCode();
goto leave;
}
#ifdef O_DIRECT
// Set O_DIRECT if the file system supports it
if ((rc = fcntl(newfd, F_GETFL)) != -1)
(void) fcntl(newfd, F_SETFL, rc | O_DIRECT);
#endif
#ifdef F_NOCACHE // __APPLE__
rc = fcntl(newfd, F_NOCACHE, 1);
if (rc) {
rc = ErrCode();
goto leave;
}
#endif
rc = mdb_env_copyfd(env, newfd);
leave:
if (!(env->me_flags & MDB_NOSUBDIR))
free(lpath);
if (newfd != INVALID_HANDLE_VALUE)
if (close(newfd) < 0 && rc == MDB_SUCCESS)
rc = ErrCode();
return rc;
*/
return nil
}
func (db *db) Close() {
/*
MDB_page *dp;
if (env == NULL)
return;
VGMEMP_DESTROY(env);
while ((dp = env->me_dpages) != NULL) {
VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
env->me_dpages = dp->mp_next;
free(dp);
}
mdb_env_close0(env, 0);
free(env);
*/
}
// Calculate the size of a leaf node.
// The size depends on the environment's page size; if a data item
// is too large it will be put onto an overflow page and the node
// size will only include the key and not the data. Sizes are always
// rounded up to an even number of bytes, to guarantee 2-byte alignment
// of the #MDB_node headers.
// @param[in] env The environment handle.
// @param[in] key The key for the node.
// @param[in] data The data for the node.
// @return The number of bytes needed to store the node.
func (db *db) LeafSize(key []byte, data []byte) int {
/*
size_t sz;
sz = LEAFSIZE(key, data);
if (sz > env->me_nodemax) {
// put on overflow page
sz -= data->mv_size - sizeof(pgno_t);
}
return EVEN(sz + sizeof(indx_t));
*/
return 0
}
// Calculate the size of a branch node.
// The size should depend on the environment's page size but since
// we currently don't support spilling large keys onto overflow
// pages, it's simply the size of the #MDB_node header plus the
// size of the key. Sizes are always rounded up to an even number
// of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
// @param[in] env The environment handle.
// @param[in] key The key for the node.
// @return The number of bytes needed to store the node.
func (db *db) BranchSize(key []byte) int {
/*
size_t sz;
sz = INDXSIZE(key);
if (sz > env->me_nodemax) {
// put on overflow page
// not implemented
// sz -= key->size - sizeof(pgno_t);
}
return sz + sizeof(indx_t);
*/
return 0
}
func (db *db) SetFlags(flag int, onoff bool) error {
/*
if ((flag & CHANGEABLE) != flag)
return EINVAL;
if (onoff)
env->me_flags |= flag;
else
env->me_flags &= ~flag;
return MDB_SUCCESS;
*/
return nil
}
func (db *db) Flags() int {
return db.flags
}
func (db *db) Stat() *Stat
/*
int toggle;
if (env == NULL || arg == NULL)
return EINVAL;
toggle = mdb_env_pick_meta(env);
stat := &Stat{}
stat->ms_psize = env->me_psize;
stat->ms_depth = db->md_depth;
stat->ms_branch_pages = db->md_branch_pages;
stat->ms_leaf_pages = db->md_leaf_pages;
stat->ms_overflow_pages = db->md_overflow_pages;
stat->ms_entries = db->md_entries;
//return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], stat);
return stat
*/
}
func (db *db) Info() *Info {
/*
int toggle;
if (env == NULL || arg == NULL)
return EINVAL;
toggle = mdb_env_pick_meta(env);
arg->me_mapaddr = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : 0;
arg->me_mapsize = env->me_mapsize;
arg->me_maxreaders = env->me_maxreaders;
// me_numreaders may be zero if this process never used any readers. Use
// the shared numreader count if it exists.
arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : env->me_numreaders;
arg->me_last_pgno = env->me_metas[toggle]->mm_last_pg;
arg->me_last_txnid = env->me_metas[toggle]->mm_txnid;
return MDB_SUCCESS;
*/
return nil
}
// TODO: Move to bucket.go
func (db *db) CloseBucket(b Bucket) {
/*
char *ptr;
if (dbi <= MAIN_DBI || dbi >= env->me_maxdbs)
return;
ptr = env->me_dbxs[dbi].md_name.mv_data;
env->me_dbxs[dbi].md_name.mv_data = NULL;
env->me_dbxs[dbi].md_name.mv_size = 0;
env->me_dbflags[dbi] = 0;
free(ptr);
*/
}
//int mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
func (db *db) getReaderList() error {
/*
unsigned int i, rdrs;
MDB_reader *mr;
char buf[64];
int rc = 0, first = 1;
if (!env || !func)
return -1;
if (!env->me_txns) {
return func("(no reader locks)\n", ctx);
}
rdrs = env->me_txns->mti_numreaders;
mr = env->me_txns->mti_readers;
for (i=0; i<rdrs; i++) {
if (mr[i].mr_pid) {
txnid_t txnid = mr[i].mr_txnid;
sprintf(buf, txnid == (txnid_t)-1 ?
"%10d %"Z"x -\n" : "%10d %"Z"x %"Z"u\n",
(int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);
if (first) {
first = 0;
rc = func(" pid thread txnid\n", ctx);
if (rc < 0)
break;
}
rc = func(buf, ctx);
if (rc < 0)
break;
}
}
if (first) {
rc = func("(no active readers)\n", ctx);
}
return rc;
*/
return nil
}
// (bool return is whether reader is dead)
func (db *db) checkReaders() (bool, error) {
/*
unsigned int i, j, rdrs;
MDB_reader *mr;
MDB_PID_T *pids, pid;
int count = 0;
if (!env)
return EINVAL;
if (dead)
*dead = 0;
if (!env->me_txns)
return MDB_SUCCESS;
rdrs = env->me_txns->mti_numreaders;
pids = malloc((rdrs+1) * sizeof(MDB_PID_T));
if (!pids)
return ENOMEM;
pids[0] = 0;
mr = env->me_txns->mti_readers;
for (i=0; i<rdrs; i++) {
if (mr[i].mr_pid && mr[i].mr_pid != env->me_pid) {
pid = mr[i].mr_pid;
if (mdb_pid_insert(pids, pid) == 0) {
if (!mdb_reader_pid(env, Pidcheck, pid)) {
LOCK_MUTEX_R(env);
// Recheck, a new process may have reused pid
if (!mdb_reader_pid(env, Pidcheck, pid)) {
for (j=i; j<rdrs; j++)
if (mr[j].mr_pid == pid) {
DPRINTF(("clear stale reader pid %u txn %"Z"d",
(unsigned) pid, mr[j].mr_txnid));
mr[j].mr_pid = 0;
count++;
}
}
UNLOCK_MUTEX_R(env);
}
}
}
}
free(pids);
if (dead)
*dead = count;
return MDB_SUCCESS;
*/
return false, nil
}
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