Understanding Ownership - The Rust Programming Language

1. The Rust Programming Language
2. Foreword
3. Introduction
4. 1. Getting Started
5. 1. 1.1. Installation
   2. 1.2. Hello, World!
   3. 1.3. Hello, Cargo!
6. 2. Programming a Guessing Game
7. 3. Common Programming Concepts
8. 1. 3.1. Variables and Mutability
   2. 3.2. Data Types
   3. 3.3. Functions
   4. 3.4. Comments
   5. 3.5. Control Flow
9. 4. Understanding Ownership
10. 1. 4.1. What is Ownership?
       2. 4.2. References and Borrowing
       3. 4.3. The Slice Type
11. 5. Using Structs to Structure Related Data
12. 1. 5.1. Defining and Instantiating Structs
       2. 5.2. An Example Program Using Structs
       3. 5.3. Method Syntax
13. 6. Enums and Pattern Matching
14. 1. 6.1. Defining an Enum
       2. 6.2. The match Control Flow Construct
       3. 6.3. Concise Control Flow with if let and let else
15. 7. Managing Growing Projects with Packages, Crates, and Modules
16. 1. 7.1. Packages and Crates
       2. 7.2. Defining Modules to Control Scope and Privacy
       3. 7.3. Paths for Referring to an Item in the Module Tree
       4. 7.4. Bringing Paths Into Scope with the use Keyword
       5. 7.5. Separating Modules into Different Files
17. 8. Common Collections
18. 1. 8.1. Storing Lists of Values with Vectors
       2. 8.2. Storing UTF-8 Encoded Text with Strings
       3. 8.3. Storing Keys with Associated Values in Hash Maps
19. 9. Error Handling
20. 1. 9.1. Unrecoverable Errors with panic!
       2. 9.2. Recoverable Errors with Result
       3. 9.3. To panic! or Not to panic!
21. 10. Generic Types, Traits, and Lifetimes
22. 1. 10.1. Generic Data Types
       2. 10.2. Traits: Defining Shared Behavior
       3. 10.3. Validating References with Lifetimes
23. 11. Writing Automated Tests
24. 1. 11.1. How to Write Tests
       2. 11.2. Controlling How Tests Are Run
       3. 11.3. Test Organization
25. 12. An I/O Project: Building a Command Line Program
26. 1. 12.1. Accepting Command Line Arguments
       2. 12.2. Reading a File
       3. 12.3. Refactoring to Improve Modularity and Error Handling
       4. 12.4. Developing the Library’s Functionality with Test Driven Development
       5. 12.5. Working with Environment Variables
       6. 12.6. Writing Error Messages to Standard Error Instead of Standard Output
27. 13. Functional Language Features: Iterators and Closures
28. 1. 13.1. Closures: Anonymous Functions that Capture Their Environment
       2. 13.2. Processing a Series of Items with Iterators
       3. 13.3. Improving Our I/O Project
       4. 13.4. Comparing Performance: Loops vs. Iterators
29. 14. More about Cargo and Crates.io
30. 1. 14.1. Customizing Builds with Release Profiles
       2. 14.2. Publishing a Crate to Crates.io
       3. 14.3. Cargo Workspaces
       4. 14.4. Installing Binaries from Crates.io with cargo install
       5. 14.5. Extending Cargo with Custom Commands
31. 15. Smart Pointers
32. 1. 15.1. Using Box to Point to Data on the Heap
       2. 15.2. Treating Smart Pointers Like Regular References with the Deref Trait
       3. 15.3. Running Code on Cleanup with the Drop Trait
       4. 15.4. Rc, the Reference Counted Smart Pointer
       5. 15.5. RefCell and the Interior Mutability Pattern
       6. 15.6. Reference Cycles Can Leak Memory
33. 16. Fearless Concurrency
34. 1. 16.1. Using Threads to Run Code Simultaneously
       2. 16.2. Using Message Passing to Transfer Data Between Threads
       3. 16.3. Shared-State Concurrency
       4. 16.4. Extensible Concurrency with the Sync and Send Traits
35. 17. Fundamentals of Asynchronous Programming: Async, Await, Futures, and Streams
36. 1. 17.1. Futures and the Async Syntax
       2. 17.2. Applying Concurrency with Async
       3. 17.3. Working With Any Number of Futures
       4. 17.4. Streams: Futures in Sequence
       5. 17.5. A Closer Look at the Traits for Async
       6. 17.6. Futures, Tasks, and Threads
37. 18. Object Oriented Programming Features of Rust
38. 1. 18.1. Characteristics of Object-Oriented Languages
       2. 18.2. Using Trait Objects That Allow for Values of Different Types
       3. 18.3. Implementing an Object-Oriented Design Pattern
39. 19. Patterns and Matching
40. 1. 19.1. All the Places Patterns Can Be Used
       2. 19.2. Refutability: Whether a Pattern Might Fail to Match
       3. 19.3. Pattern Syntax
41. 20. Advanced Features
42. 1. 20.1. Unsafe Rust
       2. 20.2. Advanced Traits
       3. 20.3. Advanced Types
       4. 20.4. Advanced Functions and Closures
       5. 20.5. Macros
43. 21. Final Project: Building a Multithreaded Web Server
44. 1. 21.1. Building a Single-Threaded Web Server
       2. 21.2. Turning Our Single-Threaded Server into a Multithreaded Server
       3. 21.3. Graceful Shutdown and Cleanup
45. 22. Appendix
46. 1. 22.1. A - Keywords
       2. 22.2. B - Operators and Symbols
       3. 22.3. C - Derivable Traits
       4. 22.4. D - Useful Development Tools
       5. 22.5. E - Editions
       6. 22.6. F - Translations of the Book
       7. 22.7. G - How Rust is Made and “Nightly Rust”

The Rust Programming Language

Understanding Ownership

Ownership is Rust’s most unique feature and has deep implications for the rest of the language. It enables Rust to make memory safety guarantees without needing a garbage collector, so it’s important to understand how ownership works. In this chapter, we’ll talk about ownership as well as several related features: borrowing, slices, and how Rust lays data out in memory.