remove read/write distinction for kv transactions; traitify database

1 files changed, 59 insertions, 0 deletions

diff --git a/database/src/kv/counters.rs b/database/src/kv/counters.rs
new file mode 100644
index 0000000..fae7b42
--- /dev/null
+++ b/database/src/kv/counters.rs
@@ -0,0 +1,59 @@
+/*
+    This file is part of jellything (https://codeberg.org/metamuffin/jellything)
+    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
+    Copyright (C) 2026 metamuffin <metamuffin.org>
+*/
+use crate::{
+    Query, RowNum,
+    kv::{self, TableNum, binning::Binning},
+};
+use anyhow::Result;
+use jellyobject::Object;
+use std::collections::HashMap;
+
+pub(crate) struct Counters(pub HashMap<Binning, TableNum>);
+impl Counters {
+    pub fn update(
+        &self,
+        txn: &mut dyn jellykv::Transaction,
+        ob: Object<'_>,
+        remove: bool,
+    ) -> Result<()> {
+        for (b, &table) in &self.0 {
+            let mut k = vec![vec![]];
+            b.apply(ob, &mut k);
+            if k.is_empty() {
+                continue;
+            }
+            let mut counter = read_counter(txn, table)?;
+            if remove {
+                counter += k.len() as u64;
+            } else {
+                counter -= k.len() as u64;
+            }
+            write_counter(txn, table, counter)?;
+        }
+        Ok(())
+    }
+    pub fn count(&self, txn: &dyn jellykv::Transaction, query: &Query) -> Result<Option<u64>> {
+        let mut total = 0;
+        for binning in query.filter.get_bins() {
+            let Some(b) = self.0.get(&binning) else {
+                return Ok(None);
+            };
+            total += read_counter(txn, *b)?;
+        }
+        Ok(Some(total))
+    }
+}
+
+pub fn write_counter(txn: &mut dyn jellykv::Transaction, t: TableNum, value: u64) -> Result<()> {
+    txn.set(&t.to_be_bytes(), &value.to_be_bytes())
+}
+pub fn read_counter(txn: &dyn jellykv::Transaction, t: TableNum) -> Result<u64> {
+    Ok(txn
+        .get(&t.to_be_bytes())?
+        .map(|k| k.as_slice().try_into().map(RowNum::from_be_bytes).ok())
+        .flatten()
+        .unwrap_or(0))
+}