From f429a8ab032647ed2a285dd7a536ef224a8adcd0 Mon Sep 17 00:00:00 2001
From: Philipp Oppermann <dev@phil-opp.com>
Date: Wed, 26 Jun 2019 15:06:40 +0200
Subject: [PATCH] Example use of Box, Vec, and Rc in kernel_main

---
 src/main.rs | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 69e73633..3ce0b620 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,7 +9,7 @@ extern crate alloc;
 use blog_os::println;
 use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
-use alloc::boxed::Box;
+use alloc::{boxed::Box, vec, vec::Vec, rc::Rc};
 
 entry_point!(kernel_main);
 
@@ -26,7 +26,23 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {
     allocator::init_heap(&mut mapper, &mut frame_allocator)
         .expect("heap initialization failed");
 
-    let x = Box::new(41);
+    // allocate a number on the heap
+    let heap_value = Box::new(41);
+    println!("heap_value at {:p}", heap_value);
+
+    // create a dynamically sized vector
+    let mut vec = Vec::new();
+    for i in 0..500 {
+        vec.push(i);
+    }
+    println!("vec at {:p}", vec.as_slice());
+
+    // create a reference counted vector -> will be deallocated when count reaches 0
+    let reference_counted = Rc::new(vec![1, 2, 3]);
+    let cloned_reference = reference_counted.clone();
+    println!("current reference count is {}", Rc::strong_count(&cloned_reference));
+    core::mem::drop(reference_counted);
+    println!("reference count is {} now", Rc::strong_count(&cloned_reference));
 
     #[cfg(test)]
     test_main();