init

03-builder-pattern/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "builder-pattern"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

03-builder-pattern/src/main.rs

@@ -0,0 +1,49 @@
+#![allow(unused)]
+
+use std::collections::HashMap;
+
+struct LockedCredentialManager {
+    entries: HashMap<String, String>,
+}
+
+struct UnlockedCredentialManager {
+    entries: HashMap<String, String>,
+}
+
+impl LockedCredentialManager {
+    pub fn new() -> LockedCredentialManager {
+        LockedCredentialManager {
+            entries: HashMap::new(),
+        }
+    }
+
+    pub fn unlock(self, master_secret: &str) -> UnlockedCredentialManager {
+        UnlockedCredentialManager {
+            entries: self.entries,
+        }
+    }
+}
+
+impl UnlockedCredentialManager {
+    pub fn set(&mut self, key: &str, secret: &str) {
+        todo!()
+    }
+
+    pub fn get(&mut self, key: &str) -> Option<&str> {
+        todo!()
+    }
+
+    pub fn lock(self) -> LockedCredentialManager {
+        LockedCredentialManager {
+            entries: self.entries,
+        }
+    }
+}
+
+fn main() {
+    let pw = LockedCredentialManager::new();
+    let mut pw = pw.unlock("pssst");
+    pw.set("foo", "bar");
+    let val = pw.get("foo");
+    pw.lock();
+}