Remove the shared impl of seq index

I actually realized this is a terrible abstraction the day I implemented
it and have since been planning to remove it.

The issue is with aliasing and potential corruption in a multi-threaded
environment. Even though we have never used it in such a context (aka
triggering UB) but we can potentially make an *accidental* use of it;
don't take it lightly: it's like modifying data while someone else is
reading it. That's not bad, that's a nightmare.

server/src/engine/core/model/mod.rs

@@ -39,7 +39,7 @@ use {
             tag::{DataTag, FullTag, TagClass, TagSelector},
         },
         error::{DatabaseError, DatabaseResult},
-        idx::{IndexBaseSpec, IndexSTCOrdRC, STIndex, STIndexSeq},
+        idx::{IndexBaseSpec, IndexSTSeqCns, STIndex, STIndexSeq},
         mem::VInline,
         ql::ddl::{
             crt::CreateModel,
@@ -51,7 +51,7 @@ use {
 };
 
 pub(in crate::engine::core) use self::delta::{DeltaKind, DeltaState, DeltaVersion};
-pub(in crate::engine::core) type Fields = IndexSTCOrdRC<Box<str>, Field>;
+pub(in crate::engine::core) type Fields = IndexSTSeqCns<Box<str>, Field>;
 
 #[derive(Debug)]
 pub struct ModelData {

server/src/engine/idx/mod.rs

@@ -41,8 +41,6 @@ use {
 
 // re-exports
 pub type IndexSTSeqCns<K, V> = stord::IndexSTSeqDll<K, V, stord::config::ConservativeConfig<K, V>>;
-pub type IndexSTCOrdRC<K, V> =
-    stord::shared::OrderedIdxRC<K, V, stord::config::ConservativeConfig<K, V>>;
 pub type IndexSTSeqLib<K, V> = stord::IndexSTSeqDll<K, V, stord::config::LiberalConfig<K, V>>;
 pub type IndexMTRC<K, V> = mtchm::imp::ChmArc<K, V, mtchm::meta::DefConfig>;
 pub type IndexMTRaw<E> = mtchm::imp::Raw<E, mtchm::meta::DefConfig>;

server/src/engine/idx/stord/mod.rs

@@ -26,7 +26,6 @@
 
 pub(super) mod config;
 mod iter;
-pub(super) mod shared;
 
 use {
     self::{

server/src/engine/idx/stord/shared.rs

@@ -1,131 +0,0 @@
-/*
- * Created on Mon May 08 2023
- *
- * This file is a part of Skytable
- * Skytable (formerly known as TerrabaseDB or Skybase) is a free and open-source
- * NoSQL database written by Sayan Nandan ("the Author") with the
- * vision to provide flexibility in data modelling without compromising
- * on performance, queryability or scalability.
- *
- * Copyright (c) 2023, Sayan Nandan <ohsayan@outlook.com>
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- *
-*/
-
-#[cfg(debug_assertions)]
-use super::IndexSTSeqDllMetrics;
-
-use {
-    super::{config::Config, IndexSTSeqDll},
-    crate::engine::{
-        idx::{AsKey, AsValue, IndexBaseSpec},
-        sync::smart::EArc,
-    },
-    std::{
-        mem::ManuallyDrop,
-        ops::{Deref, DerefMut},
-    },
-};
-
-#[derive(Debug)]
-pub struct OrderedIdxRC<K, V, C: Config<K, V>> {
-    base: ManuallyDrop<IndexSTSeqDll<K, V, C>>,
-    rc: EArc,
-}
-
-impl<K, V, C: Config<K, V>> OrderedIdxRC<K, V, C> {
-    fn new() -> Self {
-        Self::new_with(IndexSTSeqDll::new())
-    }
-    fn new_with(idx: IndexSTSeqDll<K, V, C>) -> Self {
-        Self {
-            base: ManuallyDrop::new(idx),
-            rc: unsafe {
-                // UNSAFE(@ohsayan): we'll clean this up
-                EArc::new()
-            },
-        }
-    }
-}
-
-impl<K, V, C: Config<K, V>> Deref for OrderedIdxRC<K, V, C> {
-    type Target = IndexSTSeqDll<K, V, C>;
-    fn deref(&self) -> &Self::Target {
-        &self.base
-    }
-}
-
-impl<K, V, C: Config<K, V>> DerefMut for OrderedIdxRC<K, V, C> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.base
-    }
-}
-
-impl<K, V, C: Config<K, V>> Clone for OrderedIdxRC<K, V, C> {
-    fn clone(&self) -> Self {
-        let rc = unsafe {
-            // UNSAFE(@ohsayan): called at clone position
-            self.rc.rc_clone()
-        };
-        Self {
-            base: unsafe {
-                // UNSAFE(@ohsayan): just a raw clone. no big deal since this is an RC
-                core::mem::transmute_copy(&self.base)
-            },
-            rc,
-        }
-    }
-}
-
-impl<K, V, C: Config<K, V>> Drop for OrderedIdxRC<K, V, C> {
-    fn drop(&mut self) {
-        unsafe {
-            // UNSAFE(@ohsayan): this is the dtor
-            self.rc.rc_drop(|| ManuallyDrop::drop(&mut self.base))
-        }
-    }
-}
-
-impl<K, V, C: Config<K, V>> IndexBaseSpec for OrderedIdxRC<K, V, C> {
-    const PREALLOC: bool = true;
-    #[cfg(debug_assertions)]
-    type Metrics = IndexSTSeqDllMetrics;
-
-    fn idx_init_cap(cap: usize) -> Self {
-        Self::new_with(IndexSTSeqDll::with_capacity(cap))
-    }
-
-    fn idx_init() -> Self {
-        Self::new()
-    }
-
-    fn idx_init_with(s: Self) -> Self {
-        s
-    }
-
-    #[cfg(debug_assertions)]
-    fn idx_metrics(&self) -> &Self::Metrics {
-        self.base.idx_metrics()
-    }
-}
-
-impl<K: AsKey, V: AsValue + PartialEq, C: Config<K, V>> PartialEq for OrderedIdxRC<K, V, C> {
-    fn eq(&self, other: &Self) -> bool {
-        self.len() == other.len()
-            && self
-                ._iter_unord_kv()
-                .all(|(k, v)| other._get(k).unwrap().eq(v))
-    }
-}