From 42f882ee040113c947df431cf90200fb4f5fbf3e Mon Sep 17 00:00:00 2001
From: Steven Normore <snormore@gmail.com>
Date: Wed, 24 Apr 2024 14:08:23 -0400
Subject: [PATCH] test: add basic fuzz

---
 fuzz/.gitignore                         |  4 ++
 fuzz/Cargo.lock                         | 64 +++++++++++++++++++++++++
 fuzz/Cargo.toml                         | 21 ++++++++
 fuzz/fuzz_targets/fuzz_basic_borrows.rs | 36 ++++++++++++++
 4 files changed, 125 insertions(+)
 create mode 100644 fuzz/.gitignore
 create mode 100644 fuzz/Cargo.lock
 create mode 100644 fuzz/Cargo.toml
 create mode 100644 fuzz/fuzz_targets/fuzz_basic_borrows.rs

diff --git a/fuzz/.gitignore b/fuzz/.gitignore
new file mode 100644
index 0000000..1a45eee
--- /dev/null
+++ b/fuzz/.gitignore
@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage
diff --git a/fuzz/Cargo.lock b/fuzz/Cargo.lock
new file mode 100644
index 0000000..ab6e5c9
--- /dev/null
+++ b/fuzz/Cargo.lock
@@ -0,0 +1,64 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "arbitrary"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d5a26814d8dcb93b0e5a0ff3c6d80a8843bafb21b39e8e18a6f05471870e110"
+
+[[package]]
+name = "cc"
+version = "1.0.95"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d32a725bc159af97c3e629873bb9f88fb8cf8a4867175f76dc987815ea07c83b"
+dependencies = [
+ "jobserver",
+ "libc",
+ "once_cell",
+]
+
+[[package]]
+name = "jobserver"
+version = "0.1.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2b099aaa34a9751c5bf0878add70444e1ed2dd73f347be99003d4577277de6e"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.153"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
+
+[[package]]
+name = "libfuzzer-sys"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a96cfd5557eb82f2b83fed4955246c988d331975a002961b07c81584d107e7f7"
+dependencies = [
+ "arbitrary",
+ "cc",
+ "once_cell",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
+
+[[package]]
+name = "owned_ref_cell"
+version = "0.1.0"
+
+[[package]]
+name = "owned_ref_cell-fuzz"
+version = "0.0.0"
+dependencies = [
+ "libfuzzer-sys",
+ "owned_ref_cell",
+]
diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
new file mode 100644
index 0000000..711cf8d
--- /dev/null
+++ b/fuzz/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "owned_ref_cell-fuzz"
+version = "0.0.0"
+publish = false
+edition = "2021"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.owned_ref_cell]
+path = ".."
+
+[[bin]]
+name = "fuzz_basic_borrows"
+path = "fuzz_targets/fuzz_basic_borrows.rs"
+test = false
+doc = false
+bench = false
diff --git a/fuzz/fuzz_targets/fuzz_basic_borrows.rs b/fuzz/fuzz_targets/fuzz_basic_borrows.rs
new file mode 100644
index 0000000..2fbdd38
--- /dev/null
+++ b/fuzz/fuzz_targets/fuzz_basic_borrows.rs
@@ -0,0 +1,36 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use owned_ref_cell::OwnedRefCell;
+use std::vec::Vec;
+
+fuzz_target!(|data: &[u8]| {
+    let cell = OwnedRefCell::new(0);
+    let mut immutable_borrows = Vec::new();
+    let mut mutable_borrows = Vec::new();
+
+    for &byte in data.iter() {
+        match byte % 3 {
+            0 => {
+                if let Some(borrow) = cell.try_borrow() {
+                    immutable_borrows.push(borrow); // hold the immutable borrow
+                }
+            }
+            1 => {
+                if let Some(mut borrow_mut) = cell.try_borrow_mut() {
+                    *borrow_mut += 1; // mutate the content
+                    mutable_borrows.push(borrow_mut); // hold the mutable borrow
+                }
+            }
+            _ => {
+                // Randomly drop borrows from both vectors
+                if !immutable_borrows.is_empty() {
+                    immutable_borrows.pop();
+                }
+                if !mutable_borrows.is_empty() {
+                    mutable_borrows.pop();
+                }
+            }
+        }
+    }
+});