[rm-sled] Replace unsafe code with ouroboros in sqlite adapter

2024-03-08 19:20:14 +01:00 · 2024-03-08 19:20:14 +01:00 · a46c3d2502
parent 81191d2d92
commit a46c3d2502
5 changed files with 194 additions and 109 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -74,6 +74,12 @@ dependencies = [
 "memchr",
 ]

+[[package]]
+name = "aliasable"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "250f629c0161ad8107cf89319e990051fae62832fd343083bea452d93e2205fd"
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.16"
@ -1443,6 +1449,7 @@ dependencies = [
 "heed",
 "hexdump",
 "mktemp",
+ "ouroboros",
 "rusqlite",
 "tracing",
 ]
@ -2775,6 +2782,31 @@ dependencies = [
 "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]]
 name = "outref"
 version = "0.5.1"
@ -3102,6 +3134,19 @@ dependencies = [
 "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]]
 name = "prometheus"
 version = "0.13.3"
@ -3834,6 +3879,12 @@ dependencies = [
 "der",
 ]

+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
 [[package]]
 name = "static_init"
 version = "1.0.3"
@ -4844,6 +4895,12 @@ version = "0.8.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "53be06678ed9e83edb1745eb72efc0bbcd7b5c3c35711a860906aed827a13d61"

+[[package]]
+name = "yansi"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c2861d76f58ec8fc95708b9b1e417f7b12fd72ad33c01fa6886707092dea0d3"
+
 [[package]]
 name = "zerocopy"
 version = "0.7.32"
--- a/Cargo.nix
+++ b/Cargo.nix
@ -34,7 +34,7 @@ args@{
  ignoreLockHash,
 }:
 let
-  nixifiedLockHash = "23e1504df44ec18cfc5c872c858154304c16da2a6c1f7c9f06608ef833815f30";
+  nixifiedLockHash = "17e620fad07e725e301488a3746ca3512d8785ce3077f634adde82e9e4eab2bb";
  workspaceSrc = if args.workspaceSrc == null then ./. else args.workspaceSrc;
  currentLockHash = builtins.hashFile "sha256" (workspaceSrc + /Cargo.lock);
  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 {
    name = "allocator-api2";
    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;
      ${ 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;
+      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;
      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";
    src = fetchCratesIo { inherit name version; sha256 = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"; };
    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 {
    name = "outref";
    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 {
    name = "prometheus";
    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 {
    name = "static_init";
    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 {
    name = "zerocopy";
    version = "0.7.32";
--- a/Cargo.toml
+++ b/Cargo.toml
@ -58,6 +58,7 @@ md-5 = "0.10"
 mktemp = "0.5"
 nix = { version = "0.27", default-features = false, features = ["fs"] }
 nom = "7.1"
+ouroboros = "0.18"
 parse_duration = "2.1"
 pin-project = "1.0.12"
 pnet_datalink = "0.34"
--- a/src/db/Cargo.toml
+++ b/src/db/Cargo.toml
@ -14,6 +14,7 @@ path = "lib.rs"
 [dependencies]
 err-derive.workspace = true
 hexdump.workspace = true
+ouroboros.workspace = true
 tracing.workspace = true

 heed = { workspace = true, optional = true }
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@ -1,11 +1,9 @@
 use core::ops::Bound;

 use std::borrow::BorrowMut;
-use std::marker::PhantomPinned;
-use std::pin::Pin;
-use std::ptr::NonNull;
 use std::sync::{Arc, Mutex, MutexGuard};

+use ouroboros::self_referencing;
 use rusqlite::{params, Connection, Rows, Statement, Transaction};

 use crate::{
@ -197,7 +195,7 @@ impl IDb for SqliteDb {

 		let tree = this.get_tree(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<'_>> {
@ -207,7 +205,7 @@ impl IDb for SqliteDb {

 		let tree = this.get_tree(tree)?;
 		let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree);
-		DbValueIterator::make(this, &sql, [])
+		make_iterator(this, &sql, [])
 	}

 	fn range<'r>(
@ -230,7 +228,7 @@ impl IDb for SqliteDb {
 			.map(|x| x as &dyn rusqlite::ToSql)
 			.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>(
 		&self,
@ -252,7 +250,7 @@ impl IDb for SqliteDb {
 			.map(|x| x as &dyn rusqlite::ToSql)
 			.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<'_>> {
 		let tree = self.get_tree(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<'_>> {
 		let tree = self.get_tree(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>(
@ -396,7 +394,7 @@ impl<'a> ITx for SqliteTx<'a> {
 			.map(|x| x as &dyn rusqlite::ToSql)
 			.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>(
 		&self,
@ -414,77 +412,47 @@ impl<'a> ITx for SqliteTx<'a> {
 			.map(|x| x as &dyn rusqlite::ToSql)
 			.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 ----
 // 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>,
-	stmt: Option<Statement<'a>>,
-	iter: Option<Rows<'a>>,
-	_pin: PhantomPinned,
+	#[borrows(mut db)]
+	#[covariant]
+	stmt: Statement<'this>,
 }

-impl<'a> DbValueIterator<'a> {
-	fn make<P: rusqlite::Params>(
-		db: MutexGuard<'a, SqliteDbInner>,
-		sql: &str,
-		args: P,
-	) -> Result<ValueIter<'a>> {
-		let res = DbValueIterator {
-			db,
-			stmt: None,
-			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)))
-	}
+#[self_referencing]
+struct DbValueIterator<'a> {
+	aux: DbValueIterator1<'a>,
+	#[borrows(mut aux)]
+	#[covariant]
+	iter: Rows<'this>,
 }

-impl<'a> Drop for DbValueIterator<'a> {
-	fn drop(&mut self) {
-		trace!("drop iter");
-		drop(self.iter.take());
-		drop(self.stmt.take());
-	}
+fn make_iterator<'a, P: rusqlite::Params>(
+	db: MutexGuard<'a, SqliteDbInner>,
+	sql: &str,
+	args: P,
+) -> Result<ValueIter<'a>> {
+	let aux = DbValueIterator1::try_new(db, |db| db.db.prepare(sql))?;
+	let res = DbValueIterator::try_new(aux, |aux| aux.with_stmt_mut(|stmt| stmt.query(args)))?;
+	Ok(Box::new(res))
 }

-struct DbValueIteratorPin<'a>(Pin<Box<DbValueIterator<'a>>>);
-
-impl<'a> Iterator for DbValueIteratorPin<'a> {
+impl<'a> Iterator for DbValueIterator<'a> {
 	type Item = Result<(Value, Value)>;

 	fn next(&mut self) -> Option<Self::Item> {
-		let mut_ref = Pin::as_mut(&mut self.0);
-		// This unsafe allows us to mutably access the iterator field
-		let next = unsafe { Pin::get_unchecked_mut(mut_ref).iter.as_mut()?.next() };
+		let next = self.with_iter_mut(|iter| iter.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,
 // only a Statement and a Rows object

+#[self_referencing]
 struct TxValueIterator<'a> {
 	stmt: Statement<'a>,
-	iter: Option<Rows<'a>>,
-	_pin: PhantomPinned,
+	#[borrows(mut stmt)]
+	#[covariant]
+	iter: Rows<'this>,
 }

-impl<'a> TxValueIterator<'a> {
-	fn make<P: rusqlite::Params>(
-		tx: &'a SqliteTx<'a>,
-		sql: &str,
-		args: P,
-	) -> TxOpResult<TxValueIter<'a>> {
-		let stmt = tx.tx.prepare(sql)?;
-		let res = TxValueIterator {
-			stmt,
-			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)))
-	}
+fn make_tx_iterator<'a, P: rusqlite::Params>(
+	tx: &'a SqliteTx<'a>,
+	sql: &str,
+	args: P,
+) -> TxOpResult<TxValueIter<'a>> {
+	let stmt = tx.tx.prepare(sql)?;
+	let res = TxValueIterator::try_new(stmt, |stmt| stmt.query(args))?;
+	Ok(Box::new(res))
 }

-impl<'a> Drop 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> {
+impl<'a> Iterator for TxValueIterator<'a> {
 	type Item = TxOpResult<(Value, Value)>;

 	fn next(&mut self) -> Option<Self::Item> {
-		let mut_ref = Pin::as_mut(&mut self.0);
-		// This unsafe allows us to mutably access the iterator field
-		let next = unsafe { Pin::get_unchecked_mut(mut_ref).iter.as_mut()?.next() };
+		let next = self.with_iter_mut(|iter| iter.next());
 		iter_next_row(next)
 	}
 }