From ad353eb07d1ab439b767aac765755946f339fcf5 Mon Sep 17 00:00:00 2001
From: wait-what <25844213+wait-what@users.noreply.github.com>
Date: Mon, 26 Feb 2024 19:37:06 +0200
Subject: [PATCH] Add comment support in JSON (jsonc)

---
 src/serde_json.rs | 29 ++++++++++++++++
 tests/json.rs     | 84 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/src/serde_json.rs b/src/serde_json.rs
index d59e7ad..6f3139e 100644
--- a/src/serde_json.rs
+++ b/src/serde_json.rs
@@ -432,6 +432,35 @@ impl DeJsonState {
             self.tok = DeJsonTok::Eof;
             return Ok(());
         }
+        if self.cur == '/' {
+            self.next(i);
+            match self.cur {
+                '/' => {
+                    while self.cur != '\n' && self.cur != '\0' {
+                        self.next(i);
+                    }
+                    return self.next_tok(i);
+                }
+                '*' => {
+                    let mut last = self.cur;
+                    loop {
+                        self.next(i);
+                        if self.cur == '\0' {
+                            return Err(self.err_token("MultiLineCommentClose"));
+                        }
+                        if last == '*' && self.cur == '/' {
+                            self.next(i);
+                            break;
+                        }
+                        last = self.cur;
+                    }
+                    return self.next_tok(i);
+                }
+                _ => {
+                    return Err(self.err_token("CommentOpen"));
+                }
+            }
+        }
         match self.cur {
             ':' => {
                 self.next(i);
diff --git a/tests/json.rs b/tests/json.rs
index 5622f60..41ce1b1 100644
--- a/tests/json.rs
+++ b/tests/json.rs
@@ -34,6 +34,90 @@ fn de() {
     assert_eq!(test.c, None);
 }
 
+#[test]
+fn de_inline_comment() {
+    #[derive(DeJson)]
+    pub struct Test {
+        pub a: Option<String>,
+    }
+
+    let json = r#"{ //comment
+        // comment
+        "a": "// asd"// comment
+    } // comment"#;
+
+    let test: Test = DeJson::deserialize_json(json).unwrap();
+    assert_eq!(test.a.unwrap(), "// asd");
+}
+
+#[test]
+fn de_multiline_comment() {
+    #[derive(DeJson)]
+    pub struct Test {
+        pub a: f32,
+    }
+
+    let json = r#"{ /* multiline
+        comment */
+        "a": 1 /* multiline *
+        comment */
+    } /** multiline **/"#;
+
+    let test: Test = DeJson::deserialize_json(json).unwrap();
+    assert_eq!(test.a, 1.);
+}
+
+#[test]
+fn de_illegal_inline_comment() {
+    #[derive(DeJson)]
+    pub struct Test {
+        pub a: f32,
+    }
+
+    let jsons = vec![
+        r#"{
+            "a": // comment,
+        }"#,
+        r#"{
+            / comment
+            "a": 1,
+        }"#,
+    ];
+
+    for json in jsons {
+        let test: Result<Test, _> = DeJson::deserialize_json(json);
+        assert!(test.is_err());
+    }
+}
+
+#[test]
+fn de_illegal_multiline_comment() {
+    #[derive(DeJson)]
+    pub struct Test {
+        pub a: f32,
+    }
+
+    let jsons = vec![
+        r#"{
+            /* /* comment */ */
+            "a": 1
+        }"#,
+        r#"{
+            /* comment
+            "a": 1
+        }"#,
+        r#"{
+            */
+            "a": 1
+        }"#,
+    ];
+
+    for json in jsons {
+        let test: Result<Test, _> = DeJson::deserialize_json(json);
+        assert!(test.is_err());
+    }
+}
+
 #[test]
 fn de_reorder() {
     #[derive(DeJson)]