From 3c17d6df4901904f71c35a38a88adfacf43daf5c Mon Sep 17 00:00:00 2001
From: Noah Hellman <noah@hllmn.net>
Date: Mon, 10 Apr 2023 13:23:44 +0200
Subject: [PATCH] afl: add target parse_balance

verify all containers are balanced
---
 .github/workflows/ci.yml       |  1 +
 tests/afl/Cargo.toml           |  4 ++++
 tests/afl/src/lib.rs           | 15 +++++++++++++++
 tests/afl/src/main.rs          |  1 +
 tests/afl/src/parse_balance.rs |  3 +++
 5 files changed, 24 insertions(+)
 create mode 100644 tests/afl/src/parse_balance.rs

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2ae1c5a..d02c622 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -72,6 +72,7 @@ jobs:
       matrix:
         target:
           - parse
+          - parse_balance
           - html
     runs-on: ubuntu-latest
     steps:
diff --git a/tests/afl/Cargo.toml b/tests/afl/Cargo.toml
index 70e156b..66b25e1 100644
--- a/tests/afl/Cargo.toml
+++ b/tests/afl/Cargo.toml
@@ -17,6 +17,10 @@ path = "src/main.rs"
 name = "parse"
 path = "src/parse.rs"
 
+[[bin]]
+name = "parse_balance"
+path = "src/parse_balance.rs"
+
 [[bin]]
 name = "html"
 path = "src/html.rs"
diff --git a/tests/afl/src/lib.rs b/tests/afl/src/lib.rs
index adbca14..0591238 100644
--- a/tests/afl/src/lib.rs
+++ b/tests/afl/src/lib.rs
@@ -11,6 +11,21 @@ pub fn parse(data: &[u8]) {
     }
 }
 
+/// Ensure containers are always balanced, i.e. opened and closed in correct order.
+pub fn parse_balance(data: &[u8]) {
+    if let Ok(s) = std::str::from_utf8(data) {
+        let mut open = Vec::new();
+        for event in jotdown::Parser::new(s) {
+            match event {
+                jotdown::Event::Start(c, ..) => open.push(c.clone()),
+                jotdown::Event::End(c) => assert_eq!(open.pop().unwrap(), c),
+                _ => {}
+            }
+        }
+        assert_eq!(open, &[]);
+    }
+}
+
 pub fn html(data: &[u8]) {
     if data.iter().any(|i| *i == 0) {
         return;
diff --git a/tests/afl/src/main.rs b/tests/afl/src/main.rs
index b0a66c8..ad09a2d 100644
--- a/tests/afl/src/main.rs
+++ b/tests/afl/src/main.rs
@@ -8,6 +8,7 @@ fn main() {
 
     let f = match target.as_str() {
         "parse" => jotdown_afl::parse,
+        "parse_balance" => jotdown_afl::parse_balance,
         "html" => jotdown_afl::html,
         _ => panic!("unknown target '{}'", target),
     };
diff --git a/tests/afl/src/parse_balance.rs b/tests/afl/src/parse_balance.rs
new file mode 100644
index 0000000..9118fb2
--- /dev/null
+++ b/tests/afl/src/parse_balance.rs
@@ -0,0 +1,3 @@
+fn main() {
+    afl::fuzz!(|data: &[u8]| { jotdown_afl::parse_balance(data) });
+}