Depends on #3584 to use the most up-to-date implementation of
`ThreadRng`
- Add `fill_bytes` method to `IO`
- use `thread_rng` instead of `getrandom`, as `getrandom` is much slower
and `thread_rng` offers enough security
- modify `exec_randomblob`, `exec_random` and random_rowid generation to
use methods from IO for determinism
- modified simulator IO to implement `fill_bytes`
This the PRNG for sqlite if someone is curious. It is similar to
`thread_rng`:
```c
/* Initialize the state of the random number generator once,
** the first time this routine is called.
*/
if( wsdPrng.s[0]==0 ){
sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
static const u32 chacha20_init[] = {
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
};
memcpy(&wsdPrng.s[0], chacha20_init, 16);
if( NEVER(pVfs==0) ){
memset(&wsdPrng.s[4], 0, 44);
}else{
sqlite3OsRandomness(pVfs, 44, (char*)&wsdPrng.s[4]);
}
wsdPrng.s[15] = wsdPrng.s[12];
wsdPrng.s[12] = 0;
wsdPrng.n = 0;
}
assert( N>0 );
while( 1 /* exit by break */ ){
if( N<=wsdPrng.n ){
memcpy(zBuf, &wsdPrng.out[wsdPrng.n-N], N);
wsdPrng.n -= N;
break;
}
if( wsdPrng.n>0 ){
memcpy(zBuf, wsdPrng.out, wsdPrng.n);
N -= wsdPrng.n;
zBuf += wsdPrng.n;
}
wsdPrng.s[12]++;
chacha_block((u32*)wsdPrng.out, wsdPrng.s);
wsdPrng.n = 64;
}
sqlite3_mutex_leave(mutex);
```
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#3799
I've added a trait called `CursorTrait`. I know it's not a good name for
now, but I didn't know what tto change then enum `Cursor` to. This trait
wraps all common functionality, and some functionality that is yet too
specific that needs to be fixed.
This is needed in order to have layered cursors where for example,
MvccCursor will need a fallback BTreeCursor.
Closes#3660
Rollback shouldn't modify the row version chain. This is crucial for
implementing a Non-blocking row version chain in #3499
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#3583
Yield is a completion that does not allocate any inner state. By design
it is completed from the start and has no errors. This allows lightly
yield without allocating any locks nor heap allocate inner state.
This PR add proper program abort in case of unfinished statement reset
and interruption.
Also, this PR makes rollback methods non-failing because otherwise of
their callers usually unclear (if rollback failed - what is the state of
statement/connection/transaction?)
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#3591
