Initial header parsing

src/main.rs

@@ -62,6 +62,63 @@ impl Language {
     }
 }
 
+/// A source file's header information.
+pub struct Header {
+    /// The copyrights on this source file.
+    pub copyrights: Vec<Copyright>,
+
+    /// The SPDX license identifier that this source file is covered under.
+    pub spdx: Option<String>,
+
+    /// This header's body, as a list of lines.
+    pub body: Vec<String>,
+}
+
+impl Header {
+    /// Parses a header from a list of comment-less lines.
+    pub fn parse(src: Vec<String>) -> Result<Self, HeaderError> {
+        let mut src = src.into_iter().peekable();
+        let mut copyrights = Vec::new();
+        let mut spdx = None;
+
+        while let Some(line) = src.peek() {
+            match Copyright::parse(line.as_str()) {
+                Ok(copyright) => {
+                    copyrights.push(copyright);
+                    src.next();
+                }
+                Err(CopyrightError::Empty | CopyrightError::InvalidPrefix) => {
+                    break;
+                }
+                Err(err) => {
+                    return Err(HeaderError::Copyright(err));
+                }
+            }
+        }
+
+        if let Some(line) = src.peek() {
+            if let Some(body) = line.strip_prefix("SPDX-License-Identifier: ") {
+                spdx = Some(body.to_string());
+                src.next();
+            }
+        }
+
+        let body: Vec<_> = src.collect();
+
+        Ok(Self {
+            copyrights,
+            spdx,
+            body,
+        })
+    }
+}
+
+/// An error that occurred during header parsing.
+#[derive(Clone, Copy, Debug)]
+pub enum HeaderError {
+    Copyright(CopyrightError),
+}
+
 /// A single copyright notice on a source file.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Copyright {
@@ -197,4 +254,24 @@ mod tests {
             }
         );
     }
+
+    #[test]
+    fn parse_header() {
+        let src = b"#!/bin/sh\n// Copyright (c) 2024 Marceline Cramer\n// SPDX-License-Identifier: AGPL-3.0-or-later\n// body here";
+        let lines = Language::RUST.read_header(&mut src.as_slice()).unwrap();
+        let header = Header::parse(lines).unwrap();
+
+        assert_eq!(
+            header.copyrights,
+            vec![Copyright {
+                holder: "Marceline Cramer".into(),
+                first_year: 2024,
+                last_year: 2024,
+            }]
+        );
+
+        assert_eq!(header.spdx, Some("AGPL-3.0-or-later".to_string()));
+
+        assert_eq!(header.body, vec!["body here"]);
+    }
 }