add compaction controller + simulator

Signed-off-by: Alex Chi Z <iskyzh@gmail.com>

mini-lsm/src/bin/compaction_simulator.rs

@@ -0,0 +1,84 @@
+use std::collections::HashSet;
+use std::sync::Arc;
+
+use clap::Parser;
+use mini_lsm::compact::TieredCompactionController;
+use mini_lsm::lsm_storage::LsmStorageInner;
+use mini_lsm::mem_table::MemTable;
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+enum Args {
+    Tiered {},
+    Leveled {},
+}
+
+pub struct MockStorage {
+    snapshot: LsmStorageInner,
+    next_sst_id: usize,
+    file_list: HashSet<usize>,
+}
+
+impl MockStorage {
+    pub fn new() -> Self {
+        let snapshot = LsmStorageInner {
+            memtable: Arc::new(MemTable::create()),
+            imm_memtables: Vec::new(),
+            l0_sstables: Vec::new(),
+            levels: Vec::new(),
+            sstables: Default::default(),
+        };
+        Self {
+            snapshot,
+            next_sst_id: 0,
+            file_list: Default::default(),
+        }
+    }
+
+    fn generate_sst_id(&mut self) -> usize {
+        let id = self.next_sst_id;
+        self.next_sst_id += 1;
+        id
+    }
+
+    pub fn flush_sst(&mut self) {
+        let id = self.generate_sst_id();
+        self.snapshot.l0_sstables.push(id);
+        self.file_list.insert(id);
+    }
+
+    pub fn remove(&mut self, files_to_remove: &[usize]) {
+        for file_id in files_to_remove {
+            self.file_list.remove(file_id);
+        }
+    }
+
+    pub fn dump(&self) {
+        print!("L0: {:?}", self.snapshot.l0_sstables);
+        for (level, files) in &self.snapshot.levels {
+            print!("L{level}: {:?}", files);
+        }
+    }
+}
+
+fn main() {
+    let args = Args::parse();
+    match args {
+        Args::Tiered {} => {
+            let controller = TieredCompactionController {};
+            let mut storage = MockStorage::new();
+            for i in 0..500 {
+                println!("Iteration {i}");
+                storage.flush_sst();
+                let task = controller.generate_compaction_task(&storage.snapshot);
+                let sst_id = storage.generate_sst_id();
+                let (snapshot, del) =
+                    controller.apply_compaction_result(&storage.snapshot, &task, &[sst_id]);
+                storage.snapshot = snapshot;
+                storage.remove(&del);
+                storage.dump();
+            }
+        }
+        Args::Leveled {} => {}
+    }
+}