MBox mailbox parsing support.

Author: mdecimus

examples/parse_mbox.rs

@@ -0,0 +1,21 @@
+/*
+ * Copyright Stalwart Labs, Minter Ltd. See the COPYING
+ * file at the top-level directory of this distribution.
+ *
+ * Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+ * https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+ * <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+ * option. This file may not be copied, modified, or distributed
+ * except according to those terms.
+ */
+
+use mail_parser::{parsers::mbox::MBoxParser, Message};
+
+fn main() {
+    // Read an MBox mailbox from stdin and prints each message as YAML.
+
+    for raw_message in MBoxParser::new(std::io::stdin()) {
+        let message = Message::parse(&raw_message).unwrap();
+        println!("{}", serde_yaml::to_string(&message).unwrap());
+    }
+}

src/parsers/mbox.rs

@@ -0,0 +1,123 @@
+/*
+ * Copyright Stalwart Labs, Minter Ltd. See the COPYING
+ * file at the top-level directory of this distribution.
+ *
+ * Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+ * https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+ * <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+ * option. This file may not be copied, modified, or distributed
+ * except according to those terms.
+ */
+
+use std::io::{BufRead, BufReader, Read};
+
+pub struct MBoxParser<T: Read> {
+    reader: BufReader<T>,
+    found_from: bool,
+}
+
+impl<T> MBoxParser<T>
+where
+    T: Read,
+{
+    pub fn new(reader: T) -> MBoxParser<T> {
+        MBoxParser {
+            reader: BufReader::new(reader),
+            found_from: false,
+        }
+    }
+}
+
+impl<T> Iterator for MBoxParser<T>
+where
+    T: Read,
+{
+    type Item = Vec<u8>;
+
+    fn next(&mut self) -> Option<Vec<u8>> {
+        let mut message = Vec::with_capacity(1024);
+        let mut message_line = Vec::with_capacity(80);
+
+        while self
+            .reader
+            .read_until(b'\n', &mut message_line)
+            .expect("Error while reading Mbox")
+            > 0
+        {
+            let is_from = message_line
+                .get(..5)
+                .map(|line| line == b"From ")
+                .unwrap_or(false);
+
+            if self.found_from {
+                if !is_from {
+                    if message_line[0] != b'>' {
+                        message.append(&mut message_line);
+                    } else if message_line
+                        .iter()
+                        .skip_while(|&&ch| ch == b'>')
+                        .take(5)
+                        .copied()
+                        .collect::<Vec<u8>>()
+                        == b"From "
+                    {
+                        message.extend_from_slice(&message_line[1..]);
+                        message_line.clear();
+                    } else {
+                        message.append(&mut message_line);
+                    }
+                } else {
+                    break;
+                }
+            } else {
+                if is_from {
+                    self.found_from = true;
+                }
+                message_line.clear();
+            }
+        }
+
+        if !message.is_empty() {
+            Some(message)
+        } else {
+            None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::MBoxParser;
+
+    #[test]
+    fn parse_mbox() {
+        let message = br#"From Mon, 15 Jan 2018 15:30:00 +0100
+Message 1
+
+From Mon, 15 Jan 2018 15:30:00 +0100
+Message 2
+
+From Mon, 15 Jan 2018 15:30:00 +0100
+Message 3
+>From hello
+>>From world
+>>>From test
+
+From Mon, 15 Jan 2018 15:30:00 +0100
+Message 4
+> From
+>F
+"#;
+
+        let mut parser = MBoxParser::new(&message[..]);
+
+        assert_eq!(parser.next().unwrap(), b"Message 1\n\n");
+        assert_eq!(parser.next().unwrap(), b"Message 2\n\n");
+        assert_eq!(
+            parser.next().unwrap(),
+            b"Message 3\nFrom hello\n>From world\n>>From test\n\n"
+        );
+        assert_eq!(parser.next().unwrap(), b"Message 4\n> From\n>F\n");
+        assert!(parser.next().is_none());
+    }
+}

src/parsers/mod.rs

@@ -11,5 +11,6 @@
 
 pub mod fields;
 pub mod header;
+pub mod mbox;
 pub mod message;
 pub mod mime;