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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/doc/book/listings/ch15-smart-pointers/listing-15-29 | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/doc/book/listings/ch15-smart-pointers/listing-15-29')
3 files changed, 66 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.lock b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.lock new file mode 100644 index 000000000..dd1f00a87 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.lock @@ -0,0 +1,6 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +[[package]] +name = "tree" +version = "0.1.0" + diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.toml b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.toml new file mode 100644 index 000000000..0bbf897d0 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "tree" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-29/src/main.rs b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/src/main.rs new file mode 100644 index 000000000..ea13df0eb --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-29/src/main.rs @@ -0,0 +1,54 @@ +use std::cell::RefCell; +use std::rc::{Rc, Weak}; + +#[derive(Debug)] +struct Node { + value: i32, + parent: RefCell<Weak<Node>>, + children: RefCell<Vec<Rc<Node>>>, +} + +// ANCHOR: here +fn main() { + let leaf = Rc::new(Node { + value: 3, + parent: RefCell::new(Weak::new()), + children: RefCell::new(vec![]), + }); + + println!( + "leaf strong = {}, weak = {}", + Rc::strong_count(&leaf), + Rc::weak_count(&leaf), + ); + + { + let branch = Rc::new(Node { + value: 5, + parent: RefCell::new(Weak::new()), + children: RefCell::new(vec![Rc::clone(&leaf)]), + }); + + *leaf.parent.borrow_mut() = Rc::downgrade(&branch); + + println!( + "branch strong = {}, weak = {}", + Rc::strong_count(&branch), + Rc::weak_count(&branch), + ); + + println!( + "leaf strong = {}, weak = {}", + Rc::strong_count(&leaf), + Rc::weak_count(&leaf), + ); + } + + println!("leaf parent = {:?}", leaf.parent.borrow().upgrade()); + println!( + "leaf strong = {}, weak = {}", + Rc::strong_count(&leaf), + Rc::weak_count(&leaf), + ); +} +// ANCHOR_END: here |