[rm-sled] Replace unsafe code with ouroboros in sqlite adapter
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This commit is contained in:
Alex 2024-03-08 19:20:14 +01:00
parent 81191d2d92
commit a46c3d2502
Signed by: lx
GPG key ID: 0E496D15096376BE
5 changed files with 194 additions and 109 deletions

57
Cargo.lock generated
View file

@ -74,6 +74,12 @@ dependencies = [
"memchr", "memchr",
] ]
[[package]]
name = "aliasable"
version = "0.1.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "250f629c0161ad8107cf89319e990051fae62832fd343083bea452d93e2205fd"
[[package]] [[package]]
name = "allocator-api2" name = "allocator-api2"
version = "0.2.16" version = "0.2.16"
@ -1443,6 +1449,7 @@ dependencies = [
"heed", "heed",
"hexdump", "hexdump",
"mktemp", "mktemp",
"ouroboros",
"rusqlite", "rusqlite",
"tracing", "tracing",
] ]
@ -2775,6 +2782,31 @@ dependencies = [
"num-traits", "num-traits",
] ]
[[package]]
name = "ouroboros"
version = "0.18.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "97b7be5a8a3462b752f4be3ff2b2bf2f7f1d00834902e46be2a4d68b87b0573c"
dependencies = [
"aliasable",
"ouroboros_macro",
"static_assertions",
]
[[package]]
name = "ouroboros_macro"
version = "0.18.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b645dcde5f119c2c454a92d0dfa271a2a3b205da92e4292a68ead4bdbfde1f33"
dependencies = [
"heck 0.4.1",
"itertools 0.12.1",
"proc-macro2",
"proc-macro2-diagnostics",
"quote",
"syn 2.0.48",
]
[[package]] [[package]]
name = "outref" name = "outref"
version = "0.5.1" version = "0.5.1"
@ -3102,6 +3134,19 @@ dependencies = [
"unicode-ident", "unicode-ident",
] ]
[[package]]
name = "proc-macro2-diagnostics"
version = "0.10.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "af066a9c399a26e020ada66a034357a868728e72cd426f3adcd35f80d88d88c8"
dependencies = [
"proc-macro2",
"quote",
"syn 2.0.48",
"version_check",
"yansi",
]
[[package]] [[package]]
name = "prometheus" name = "prometheus"
version = "0.13.3" version = "0.13.3"
@ -3834,6 +3879,12 @@ dependencies = [
"der", "der",
] ]
[[package]]
name = "static_assertions"
version = "1.1.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
[[package]] [[package]]
name = "static_init" name = "static_init"
version = "1.0.3" version = "1.0.3"
@ -4844,6 +4895,12 @@ version = "0.8.8"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "53be06678ed9e83edb1745eb72efc0bbcd7b5c3c35711a860906aed827a13d61" checksum = "53be06678ed9e83edb1745eb72efc0bbcd7b5c3c35711a860906aed827a13d61"
[[package]]
name = "yansi"
version = "1.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6c2861d76f58ec8fc95708b9b1e417f7b12fd72ad33c01fa6886707092dea0d3"
[[package]] [[package]]
name = "zerocopy" name = "zerocopy"
version = "0.7.32" version = "0.7.32"

View file

@ -34,7 +34,7 @@ args@{
ignoreLockHash, ignoreLockHash,
}: }:
let let
nixifiedLockHash = "23e1504df44ec18cfc5c872c858154304c16da2a6c1f7c9f06608ef833815f30"; nixifiedLockHash = "17e620fad07e725e301488a3746ca3512d8785ce3077f634adde82e9e4eab2bb";
workspaceSrc = if args.workspaceSrc == null then ./. else args.workspaceSrc; workspaceSrc = if args.workspaceSrc == null then ./. else args.workspaceSrc;
currentLockHash = builtins.hashFile "sha256" (workspaceSrc + /Cargo.lock); currentLockHash = builtins.hashFile "sha256" (workspaceSrc + /Cargo.lock);
lockHashIgnored = if ignoreLockHash lockHashIgnored = if ignoreLockHash
@ -176,6 +176,17 @@ in
}; };
}); });
"registry+https://github.com/rust-lang/crates.io-index".aliasable."0.1.3" = overridableMkRustCrate (profileName: rec {
name = "aliasable";
version = "0.1.3";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "250f629c0161ad8107cf89319e990051fae62832fd343083bea452d93e2205fd"; };
features = builtins.concatLists [
[ "alloc" ]
[ "default" ]
];
});
"registry+https://github.com/rust-lang/crates.io-index".allocator-api2."0.2.16" = overridableMkRustCrate (profileName: rec { "registry+https://github.com/rust-lang/crates.io-index".allocator-api2."0.2.16" = overridableMkRustCrate (profileName: rec {
name = "allocator-api2"; name = "allocator-api2";
version = "0.2.16"; version = "0.2.16";
@ -2095,6 +2106,7 @@ in
err_derive = (buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".err-derive."0.3.1" { profileName = "__noProfile"; }).out; err_derive = (buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".err-derive."0.3.1" { profileName = "__noProfile"; }).out;
${ if rootFeatures' ? "garage/default" || rootFeatures' ? "garage/lmdb" || rootFeatures' ? "garage_db/default" || rootFeatures' ? "garage_db/heed" || rootFeatures' ? "garage_db/lmdb" || rootFeatures' ? "garage_model/default" || rootFeatures' ? "garage_model/lmdb" then "heed" else null } = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".heed."0.11.0" { inherit profileName; }).out; ${ if rootFeatures' ? "garage/default" || rootFeatures' ? "garage/lmdb" || rootFeatures' ? "garage_db/default" || rootFeatures' ? "garage_db/heed" || rootFeatures' ? "garage_db/lmdb" || rootFeatures' ? "garage_model/default" || rootFeatures' ? "garage_model/lmdb" then "heed" else null } = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".heed."0.11.0" { inherit profileName; }).out;
hexdump = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".hexdump."0.1.1" { inherit profileName; }).out; hexdump = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".hexdump."0.1.1" { inherit profileName; }).out;
ouroboros = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".ouroboros."0.18.3" { inherit profileName; }).out;
${ if rootFeatures' ? "garage/bundled-libs" || rootFeatures' ? "garage/default" || rootFeatures' ? "garage/sqlite" || rootFeatures' ? "garage_db/bundled-libs" || rootFeatures' ? "garage_db/default" || rootFeatures' ? "garage_db/rusqlite" || rootFeatures' ? "garage_db/sqlite" || rootFeatures' ? "garage_model/default" || rootFeatures' ? "garage_model/sqlite" then "rusqlite" else null } = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".rusqlite."0.30.0" { inherit profileName; }).out; ${ if rootFeatures' ? "garage/bundled-libs" || rootFeatures' ? "garage/default" || rootFeatures' ? "garage/sqlite" || rootFeatures' ? "garage_db/bundled-libs" || rootFeatures' ? "garage_db/default" || rootFeatures' ? "garage_db/rusqlite" || rootFeatures' ? "garage_db/sqlite" || rootFeatures' ? "garage_model/default" || rootFeatures' ? "garage_model/sqlite" then "rusqlite" else null } = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".rusqlite."0.30.0" { inherit profileName; }).out;
tracing = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing."0.1.40" { inherit profileName; }).out; tracing = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing."0.1.40" { inherit profileName; }).out;
}; };
@ -2510,7 +2522,7 @@ in
registry = "registry+https://github.com/rust-lang/crates.io-index"; registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"; }; src = fetchCratesIo { inherit name version; sha256 = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"; };
features = builtins.concatLists [ features = builtins.concatLists [
(lib.optional (rootFeatures' ? "k2v-client/clap" || rootFeatures' ? "k2v-client/cli") "default") [ "default" ]
]; ];
}); });
@ -3958,6 +3970,40 @@ in
}; };
}); });
"registry+https://github.com/rust-lang/crates.io-index".ouroboros."0.18.3" = overridableMkRustCrate (profileName: rec {
name = "ouroboros";
version = "0.18.3";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "97b7be5a8a3462b752f4be3ff2b2bf2f7f1d00834902e46be2a4d68b87b0573c"; };
features = builtins.concatLists [
[ "default" ]
[ "std" ]
];
dependencies = {
aliasable = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".aliasable."0.1.3" { inherit profileName; }).out;
ouroboros_macro = (buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".ouroboros_macro."0.18.3" { profileName = "__noProfile"; }).out;
static_assertions = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".static_assertions."1.1.0" { inherit profileName; }).out;
};
});
"registry+https://github.com/rust-lang/crates.io-index".ouroboros_macro."0.18.3" = overridableMkRustCrate (profileName: rec {
name = "ouroboros_macro";
version = "0.18.3";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "b645dcde5f119c2c454a92d0dfa271a2a3b205da92e4292a68ead4bdbfde1f33"; };
features = builtins.concatLists [
[ "std" ]
];
dependencies = {
heck = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".heck."0.4.1" { inherit profileName; }).out;
itertools = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".itertools."0.12.1" { inherit profileName; }).out;
proc_macro2 = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".proc-macro2."1.0.78" { inherit profileName; }).out;
proc_macro2_diagnostics = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".proc-macro2-diagnostics."0.10.1" { inherit profileName; }).out;
quote = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".quote."1.0.35" { inherit profileName; }).out;
syn = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".syn."2.0.48" { inherit profileName; }).out;
};
});
"registry+https://github.com/rust-lang/crates.io-index".outref."0.5.1" = overridableMkRustCrate (profileName: rec { "registry+https://github.com/rust-lang/crates.io-index".outref."0.5.1" = overridableMkRustCrate (profileName: rec {
name = "outref"; name = "outref";
version = "0.5.1"; version = "0.5.1";
@ -4394,6 +4440,27 @@ in
}; };
}); });
"registry+https://github.com/rust-lang/crates.io-index".proc-macro2-diagnostics."0.10.1" = overridableMkRustCrate (profileName: rec {
name = "proc-macro2-diagnostics";
version = "0.10.1";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "af066a9c399a26e020ada66a034357a868728e72cd426f3adcd35f80d88d88c8"; };
features = builtins.concatLists [
[ "colors" ]
[ "default" ]
[ "yansi" ]
];
dependencies = {
proc_macro2 = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".proc-macro2."1.0.78" { inherit profileName; }).out;
quote = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".quote."1.0.35" { inherit profileName; }).out;
syn = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".syn."2.0.48" { inherit profileName; }).out;
yansi = (rustPackages."registry+https://github.com/rust-lang/crates.io-index".yansi."1.0.0" { inherit profileName; }).out;
};
buildDependencies = {
version_check = (buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".version_check."0.9.4" { profileName = "__noProfile"; }).out;
};
});
"registry+https://github.com/rust-lang/crates.io-index".prometheus."0.13.3" = overridableMkRustCrate (profileName: rec { "registry+https://github.com/rust-lang/crates.io-index".prometheus."0.13.3" = overridableMkRustCrate (profileName: rec {
name = "prometheus"; name = "prometheus";
version = "0.13.3"; version = "0.13.3";
@ -5466,6 +5533,13 @@ in
}; };
}); });
"registry+https://github.com/rust-lang/crates.io-index".static_assertions."1.1.0" = overridableMkRustCrate (profileName: rec {
name = "static_assertions";
version = "1.1.0";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"; };
});
"registry+https://github.com/rust-lang/crates.io-index".static_init."1.0.3" = overridableMkRustCrate (profileName: rec { "registry+https://github.com/rust-lang/crates.io-index".static_init."1.0.3" = overridableMkRustCrate (profileName: rec {
name = "static_init"; name = "static_init";
version = "1.0.3"; version = "1.0.3";
@ -6957,6 +7031,18 @@ in
]; ];
}); });
"registry+https://github.com/rust-lang/crates.io-index".yansi."1.0.0" = overridableMkRustCrate (profileName: rec {
name = "yansi";
version = "1.0.0";
registry = "registry+https://github.com/rust-lang/crates.io-index";
src = fetchCratesIo { inherit name version; sha256 = "6c2861d76f58ec8fc95708b9b1e417f7b12fd72ad33c01fa6886707092dea0d3"; };
features = builtins.concatLists [
[ "alloc" ]
[ "default" ]
[ "std" ]
];
});
"registry+https://github.com/rust-lang/crates.io-index".zerocopy."0.7.32" = overridableMkRustCrate (profileName: rec { "registry+https://github.com/rust-lang/crates.io-index".zerocopy."0.7.32" = overridableMkRustCrate (profileName: rec {
name = "zerocopy"; name = "zerocopy";
version = "0.7.32"; version = "0.7.32";

View file

@ -58,6 +58,7 @@ md-5 = "0.10"
mktemp = "0.5" mktemp = "0.5"
nix = { version = "0.27", default-features = false, features = ["fs"] } nix = { version = "0.27", default-features = false, features = ["fs"] }
nom = "7.1" nom = "7.1"
ouroboros = "0.18"
parse_duration = "2.1" parse_duration = "2.1"
pin-project = "1.0.12" pin-project = "1.0.12"
pnet_datalink = "0.34" pnet_datalink = "0.34"

View file

@ -14,6 +14,7 @@ path = "lib.rs"
[dependencies] [dependencies]
err-derive.workspace = true err-derive.workspace = true
hexdump.workspace = true hexdump.workspace = true
ouroboros.workspace = true
tracing.workspace = true tracing.workspace = true
heed = { workspace = true, optional = true } heed = { workspace = true, optional = true }

View file

@ -1,11 +1,9 @@
use core::ops::Bound; use core::ops::Bound;
use std::borrow::BorrowMut; use std::borrow::BorrowMut;
use std::marker::PhantomPinned;
use std::pin::Pin;
use std::ptr::NonNull;
use std::sync::{Arc, Mutex, MutexGuard}; use std::sync::{Arc, Mutex, MutexGuard};
use ouroboros::self_referencing;
use rusqlite::{params, Connection, Rows, Statement, Transaction}; use rusqlite::{params, Connection, Rows, Statement, Transaction};
use crate::{ use crate::{
@ -197,7 +195,7 @@ impl IDb for SqliteDb {
let tree = this.get_tree(tree)?; let tree = this.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k ASC", tree); let sql = format!("SELECT k, v FROM {} ORDER BY k ASC", tree);
DbValueIterator::make(this, &sql, []) make_iterator(this, &sql, [])
} }
fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>> { fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>> {
@ -207,7 +205,7 @@ impl IDb for SqliteDb {
let tree = this.get_tree(tree)?; let tree = this.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree); let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree);
DbValueIterator::make(this, &sql, []) make_iterator(this, &sql, [])
} }
fn range<'r>( fn range<'r>(
@ -230,7 +228,7 @@ impl IDb for SqliteDb {
.map(|x| x as &dyn rusqlite::ToSql) .map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>(); .collect::<Vec<_>>();
DbValueIterator::make::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref()) make_iterator::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref())
} }
fn range_rev<'r>( fn range_rev<'r>(
&self, &self,
@ -252,7 +250,7 @@ impl IDb for SqliteDb {
.map(|x| x as &dyn rusqlite::ToSql) .map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>(); .collect::<Vec<_>>();
DbValueIterator::make::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref()) make_iterator::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref())
} }
// ---- // ----
@ -372,12 +370,12 @@ impl<'a> ITx for SqliteTx<'a> {
fn iter(&self, tree: usize) -> TxOpResult<TxValueIter<'_>> { fn iter(&self, tree: usize) -> TxOpResult<TxValueIter<'_>> {
let tree = self.get_tree(tree)?; let tree = self.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k ASC", tree); let sql = format!("SELECT k, v FROM {} ORDER BY k ASC", tree);
TxValueIterator::make(self, &sql, []) make_tx_iterator(self, &sql, [])
} }
fn iter_rev(&self, tree: usize) -> TxOpResult<TxValueIter<'_>> { fn iter_rev(&self, tree: usize) -> TxOpResult<TxValueIter<'_>> {
let tree = self.get_tree(tree)?; let tree = self.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree); let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree);
TxValueIterator::make(self, &sql, []) make_tx_iterator(self, &sql, [])
} }
fn range<'r>( fn range<'r>(
@ -396,7 +394,7 @@ impl<'a> ITx for SqliteTx<'a> {
.map(|x| x as &dyn rusqlite::ToSql) .map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>(); .collect::<Vec<_>>();
TxValueIterator::make::<&[&dyn rusqlite::ToSql]>(self, &sql, params.as_ref()) make_tx_iterator::<&[&dyn rusqlite::ToSql]>(self, &sql, params.as_ref())
} }
fn range_rev<'r>( fn range_rev<'r>(
&self, &self,
@ -414,77 +412,47 @@ impl<'a> ITx for SqliteTx<'a> {
.map(|x| x as &dyn rusqlite::ToSql) .map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>(); .collect::<Vec<_>>();
TxValueIterator::make::<&[&dyn rusqlite::ToSql]>(self, &sql, params.as_ref()) make_tx_iterator::<&[&dyn rusqlite::ToSql]>(self, &sql, params.as_ref())
} }
} }
// ---- iterators outside transactions ---- // ---- iterators outside transactions ----
// complicated, they must hold the Statement and Row objects // complicated, they must hold the Statement and Row objects
// therefore quite some unsafe code (it is a self-referential struct) // so we need a self_referencing struct
struct DbValueIterator<'a> { // need to split in two because sequential mutable borrows are broken,
// see https://github.com/someguynamedjosh/ouroboros/issues/100
#[self_referencing]
struct DbValueIterator1<'a> {
db: MutexGuard<'a, SqliteDbInner>, db: MutexGuard<'a, SqliteDbInner>,
stmt: Option<Statement<'a>>, #[borrows(mut db)]
iter: Option<Rows<'a>>, #[covariant]
_pin: PhantomPinned, stmt: Statement<'this>,
} }
impl<'a> DbValueIterator<'a> { #[self_referencing]
fn make<P: rusqlite::Params>( struct DbValueIterator<'a> {
aux: DbValueIterator1<'a>,
#[borrows(mut aux)]
#[covariant]
iter: Rows<'this>,
}
fn make_iterator<'a, P: rusqlite::Params>(
db: MutexGuard<'a, SqliteDbInner>, db: MutexGuard<'a, SqliteDbInner>,
sql: &str, sql: &str,
args: P, args: P,
) -> Result<ValueIter<'a>> { ) -> Result<ValueIter<'a>> {
let res = DbValueIterator { let aux = DbValueIterator1::try_new(db, |db| db.db.prepare(sql))?;
db, let res = DbValueIterator::try_new(aux, |aux| aux.with_stmt_mut(|stmt| stmt.query(args)))?;
stmt: None, Ok(Box::new(res))
iter: None,
_pin: PhantomPinned,
};
let mut boxed = Box::pin(res);
trace!("make iterator with sql: {}", sql);
// This unsafe allows us to bypass lifetime checks
let db = unsafe { NonNull::from(&boxed.db).as_ref() };
let stmt = db.db.prepare(sql)?;
let mut_ref = Pin::as_mut(&mut boxed);
// This unsafe allows us to write in a field of the pinned struct
unsafe {
Pin::get_unchecked_mut(mut_ref).stmt = Some(stmt);
}
// This unsafe allows us to bypass lifetime checks
let stmt = unsafe { NonNull::from(&boxed.stmt).as_mut() };
let iter = stmt.as_mut().unwrap().query(args)?;
let mut_ref = Pin::as_mut(&mut boxed);
// This unsafe allows us to write in a field of the pinned struct
unsafe {
Pin::get_unchecked_mut(mut_ref).iter = Some(iter);
}
Ok(Box::new(DbValueIteratorPin(boxed)))
}
} }
impl<'a> Drop for DbValueIterator<'a> { impl<'a> Iterator for DbValueIterator<'a> {
fn drop(&mut self) {
trace!("drop iter");
drop(self.iter.take());
drop(self.stmt.take());
}
}
struct DbValueIteratorPin<'a>(Pin<Box<DbValueIterator<'a>>>);
impl<'a> Iterator for DbValueIteratorPin<'a> {
type Item = Result<(Value, Value)>; type Item = Result<(Value, Value)>;
fn next(&mut self) -> Option<Self::Item> { fn next(&mut self) -> Option<Self::Item> {
let mut_ref = Pin::as_mut(&mut self.0); let next = self.with_iter_mut(|iter| iter.next());
// This unsafe allows us to mutably access the iterator field
let next = unsafe { Pin::get_unchecked_mut(mut_ref).iter.as_mut()?.next() };
iter_next_row(next) iter_next_row(next)
} }
} }
@ -493,57 +461,29 @@ impl<'a> Iterator for DbValueIteratorPin<'a> {
// it's the same except we don't hold a mutex guard, // it's the same except we don't hold a mutex guard,
// only a Statement and a Rows object // only a Statement and a Rows object
#[self_referencing]
struct TxValueIterator<'a> { struct TxValueIterator<'a> {
stmt: Statement<'a>, stmt: Statement<'a>,
iter: Option<Rows<'a>>, #[borrows(mut stmt)]
_pin: PhantomPinned, #[covariant]
iter: Rows<'this>,
} }
impl<'a> TxValueIterator<'a> { fn make_tx_iterator<'a, P: rusqlite::Params>(
fn make<P: rusqlite::Params>(
tx: &'a SqliteTx<'a>, tx: &'a SqliteTx<'a>,
sql: &str, sql: &str,
args: P, args: P,
) -> TxOpResult<TxValueIter<'a>> { ) -> TxOpResult<TxValueIter<'a>> {
let stmt = tx.tx.prepare(sql)?; let stmt = tx.tx.prepare(sql)?;
let res = TxValueIterator { let res = TxValueIterator::try_new(stmt, |stmt| stmt.query(args))?;
stmt, Ok(Box::new(res))
iter: None,
_pin: PhantomPinned,
};
let mut boxed = Box::pin(res);
trace!("make iterator with sql: {}", sql);
// This unsafe allows us to bypass lifetime checks
let stmt = unsafe { NonNull::from(&boxed.stmt).as_mut() };
let iter = stmt.query(args)?;
let mut_ref = Pin::as_mut(&mut boxed);
// This unsafe allows us to write in a field of the pinned struct
unsafe {
Pin::get_unchecked_mut(mut_ref).iter = Some(iter);
}
Ok(Box::new(TxValueIteratorPin(boxed)))
}
} }
impl<'a> Drop for TxValueIterator<'a> { impl<'a> Iterator for TxValueIterator<'a> {
fn drop(&mut self) {
trace!("drop iter");
drop(self.iter.take());
}
}
struct TxValueIteratorPin<'a>(Pin<Box<TxValueIterator<'a>>>);
impl<'a> Iterator for TxValueIteratorPin<'a> {
type Item = TxOpResult<(Value, Value)>; type Item = TxOpResult<(Value, Value)>;
fn next(&mut self) -> Option<Self::Item> { fn next(&mut self) -> Option<Self::Item> {
let mut_ref = Pin::as_mut(&mut self.0); let next = self.with_iter_mut(|iter| iter.next());
// This unsafe allows us to mutably access the iterator field
let next = unsafe { Pin::get_unchecked_mut(mut_ref).iter.as_mut()?.next() };
iter_next_row(next) iter_next_row(next)
} }
} }