improvement: allow rocksdb again

src/database/abstraction/rocksdb.rs

@@ -0,0 +1,183 @@
+use super::super::Config;
+use crate::{utils, Result};
+
+use std::{future::Future, pin::Pin, sync::Arc};
+
+use super::{DatabaseEngine, Tree};
+
+use std::{collections::HashMap, sync::RwLock};
+
+pub struct Engine {
+    rocks: rocksdb::DBWithThreadMode<rocksdb::MultiThreaded>,
+    old_cfs: Vec<String>,
+}
+
+pub struct RocksDbEngineTree<'a> {
+    db: Arc<Engine>,
+    name: &'a str,
+    watchers: Watchers,
+}
+
+impl DatabaseEngine for Engine {
+    fn open(config: &Config) -> Result<Arc<Self>> {
+        let mut db_opts = rocksdb::Options::default();
+        db_opts.create_if_missing(true);
+        db_opts.set_max_open_files(16);
+        db_opts.set_compaction_style(rocksdb::DBCompactionStyle::Level);
+        db_opts.set_compression_type(rocksdb::DBCompressionType::Snappy);
+        db_opts.set_target_file_size_base(256 << 20);
+        db_opts.set_write_buffer_size(256 << 20);
+
+        let mut block_based_options = rocksdb::BlockBasedOptions::default();
+        block_based_options.set_block_size(512 << 10);
+        db_opts.set_block_based_table_factory(&block_based_options);
+
+        let cfs = rocksdb::DBWithThreadMode::<rocksdb::MultiThreaded>::list_cf(
+            &db_opts,
+            &config.database_path,
+        )
+        .unwrap_or_default();
+
+        let db = rocksdb::DBWithThreadMode::<rocksdb::MultiThreaded>::open_cf_descriptors(
+            &db_opts,
+            &config.database_path,
+            cfs.iter().map(|name| {
+                let mut options = rocksdb::Options::default();
+                let prefix_extractor = rocksdb::SliceTransform::create_fixed_prefix(1);
+                options.set_prefix_extractor(prefix_extractor);
+                options.set_merge_operator_associative("increment", utils::increment_rocksdb);
+
+                rocksdb::ColumnFamilyDescriptor::new(name, options)
+            }),
+        )?;
+
+        Ok(Arc::new(Engine {
+            rocks: db,
+            old_cfs: cfs,
+        }))
+    }
+
+    fn open_tree(self: &Arc<Self>, name: &'static str) -> Result<Arc<dyn Tree>> {
+        if !self.old_cfs.contains(&name.to_owned()) {
+            // Create if it didn't exist
+            let mut options = rocksdb::Options::default();
+            let prefix_extractor = rocksdb::SliceTransform::create_fixed_prefix(1);
+            options.set_prefix_extractor(prefix_extractor);
+            options.set_merge_operator_associative("increment", utils::increment_rocksdb);
+
+            let _ = self.rocks.create_cf(name, &options);
+            println!("created cf");
+        }
+
+        Ok(Arc::new(RocksDbEngineTree {
+            name,
+            db: Arc::clone(self),
+            watchers: Watchers::default(),
+        }))
+    }
+
+    fn flush(self: &Arc<Self>) -> Result<()> {
+        // TODO?
+        Ok(())
+    }
+}
+
+impl RocksDbEngineTree<'_> {
+    fn cf(&self) -> rocksdb::BoundColumnFamily<'_> {
+        self.db.rocks.cf_handle(self.name).unwrap()
+    }
+}
+
+impl Tree for RocksDbEngineTree<'_> {
+    fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>> {
+        Ok(self.db.rocks.get_cf(self.cf(), key)?)
+    }
+
+    fn insert(&self, key: &[u8], value: &[u8]) -> Result<()> {
+        self.db.rocks.put_cf(self.cf(), key, value)?;
+        self.watchers.wake(key);
+        Ok(())
+    }
+
+    fn insert_batch<'a>(&self, iter: &mut dyn Iterator<Item = (Vec<u8>, Vec<u8>)>) -> Result<()> {
+        for (key, value) in iter {
+            self.db.rocks.put_cf(self.cf(), key, value)?;
+        }
+
+        Ok(())
+    }
+
+    fn remove(&self, key: &[u8]) -> Result<()> {
+        Ok(self.db.rocks.delete_cf(self.cf(), key)?)
+    }
+
+    fn iter<'a>(&'a self) -> Box<dyn Iterator<Item = (Vec<u8>, Vec<u8>)> + 'a> {
+        Box::new(
+            self.db
+                .rocks
+                .iterator_cf(self.cf(), rocksdb::IteratorMode::Start)
+                .map(|(k, v)| (Vec::from(k), Vec::from(v))),
+        )
+    }
+
+    fn iter_from<'a>(
+        &'a self,
+        from: &[u8],
+        backwards: bool,
+    ) -> Box<dyn Iterator<Item = (Vec<u8>, Vec<u8>)> + 'a> {
+        Box::new(
+            self.db
+                .rocks
+                .iterator_cf(
+                    self.cf(),
+                    rocksdb::IteratorMode::From(
+                        from,
+                        if backwards {
+                            rocksdb::Direction::Reverse
+                        } else {
+                            rocksdb::Direction::Forward
+                        },
+                    ),
+                )
+                .map(|(k, v)| (Vec::from(k), Vec::from(v))),
+        )
+    }
+
+    fn increment(&self, key: &[u8]) -> Result<Vec<u8>> {
+        // TODO: make atomic
+        let old = self.db.rocks.get_cf(self.cf(), &key)?;
+        let new = utils::increment(old.as_deref()).unwrap();
+        self.db.rocks.put_cf(self.cf(), key, &new)?;
+        Ok(new)
+    }
+
+    fn increment_batch<'a>(&self, iter: &mut dyn Iterator<Item = Vec<u8>>) -> Result<()> {
+        for key in iter {
+            let old = self.db.rocks.get_cf(self.cf(), &key)?;
+            let new = utils::increment(old.as_deref()).unwrap();
+            self.db.rocks.put_cf(self.cf(), key, new)?;
+        }
+
+        Ok(())
+    }
+
+    fn scan_prefix<'a>(
+        &'a self,
+        prefix: Vec<u8>,
+    ) -> Box<dyn Iterator<Item = (Vec<u8>, Vec<u8>)> + 'a> {
+        Box::new(
+            self.db
+                .rocks
+                .iterator_cf(
+                    self.cf(),
+                    rocksdb::IteratorMode::From(&prefix, rocksdb::Direction::Forward),
+                )
+                .map(|(k, v)| (Vec::from(k), Vec::from(v)))
+                .take_while(move |(k, _)| k.starts_with(&prefix)),
+        )
+    }
+
+    fn watch_prefix<'a>(&'a self, prefix: &[u8]) -> Pin<Box<dyn Future<Output = ()> + Send + 'a>> {
+        self.watchers.watch(prefix)
+    }
+}