implement memory pool for bookmark index

src/profile/bookmark.rs

@@ -1,21 +1,49 @@
 mod database;
+mod memory;
+
 use database::Database;
+use memory::Memory;
 
 use sqlite::{Connection, Transaction};
 use std::{rc::Rc, sync::RwLock};
 
 pub struct Bookmark {
-    pub database: Rc<Database>,
+    database: Rc<Database>,
+    memory: Rc<Memory>,
 }
 
 impl Bookmark {
     // Constructors
 
+    /// Create new `Self`
     pub fn new(connection: Rc<RwLock<Connection>>, profile_id: i64) -> Self {
-        Self {
-            database: Rc::new(Database::new(connection, profile_id)),
+        // Init children components
+        let database = Rc::new(Database::new(connection, profile_id));
+        let memory = Rc::new(Memory::new());
+
+        // Build initial index
+        for record in database.records(None) {
+            memory.set(record.request, record.time)
+        }
+
+        // Return new `Self`
+        Self { database, memory }
+    }
+
+    // Actions
+
+    /// Check request exist in:
+    /// * memory if `is_memory` is `true` (fast)
+    /// * database if `is_memory` is `false` (slow)
+    pub fn has_request(&self, request: &str, is_memory: bool) -> bool {
+        if is_memory {
+            self.memory.is_exist(request)
+        } else {
+            !self.database.records(Some(request)).is_empty()
         }
     }
+
+    // @TODO add new record with index update
 }
 
 // Tools

src/profile/bookmark/memory.rs

@@ -0,0 +1,38 @@
+use gtk::glib::DateTime;
+use std::{cell::RefCell, collections::HashMap};
+
+/// Reduce disk usage by cache results in memory
+pub struct Memory {
+    index: RefCell<HashMap<String, DateTime>>,
+}
+
+impl Memory {
+    // Constructors
+
+    pub fn new() -> Self {
+        Self {
+            index: RefCell::new(HashMap::new()),
+        }
+    }
+
+    // Actions
+
+    /// Set new record
+    /// * replace existing record with new value
+    pub fn set(&self, request: String, time: DateTime) {
+        // Borrow index to update
+        let mut index = self.index.borrow_mut();
+
+        // Cleanup previous record
+        if index.get(&request).is_some() {
+            index.remove(&request);
+        }
+
+        // Insert new record with actual data
+        index.insert(request, time);
+    }
+
+    pub fn is_exist(&self, request: &str) -> bool {
+        self.index.borrow().get(request).is_some()
+    }
+}