parse into tasks

src/main.rs

@@ -1,103 +1,12 @@
-mod nibbler;
+mod tdb2;
+mod task;
 
-use std::str;
-
-use std::io::{stdin, BufRead, Result, Error, ErrorKind};
-use nibbler::Nibbler;
-
-/// Decode the given byte slice into a string using Taskwarrior JSON's escaping The slice is
-/// assumed to be ASCII; unicode escapes within it will be expanded.
-// TODO: return Cow
-fn json_decode(value: &[u8]) -> String {
-    let length = value.len();
-    let mut rv = String::with_capacity(length);
-
-    let mut pos = 0;
-    while pos < length {
-        let v = value[pos];
-        if v == b'\\' {
-            pos += 1;
-            if pos == length {
-                rv.push(v as char);
-                break;
-            }
-            let v = value[pos];
-            match v {
-                b'"' | b'\\' | b'/' => rv.push(v as char),
-                b'b' => rv.push(8 as char),
-                b'f' => rv.push(12 as char),
-                b'n' => rv.push('\n' as char),
-                b'r' => rv.push('\r' as char),
-                b't' => rv.push('\t' as char),
-                b'u' => panic!("omg please no"),
-                _ => {
-                    rv.push(b'\\' as char);
-                    rv.push(v as char);
-                }
-            }
-        } else {
-            rv.push(v as char)
-        }
-        pos += 1;
-    }
-
-    rv
-}
-
-fn decode(value: String) -> String {
-    if let Some(_) = value.find('&') {
-        return value.replace("&open;", "[").replace("&close;", "]");
-    }
-    value
-}
-
-fn parse_ff4(line: &str) -> Result<()> {
-    let mut nib = Nibbler::new(line.as_bytes());
-    println!("{}", line);
-
-    if !nib.skip(b'[') {
-        return Err(Error::new(ErrorKind::Other, "bad line"));
-    }
-    if let Some(line) = nib.get_until(b']') {
-        let mut nib = Nibbler::new(line);
-        while !nib.depleted() {
-            if let Some(name) = nib.get_until(b':') {
-                if !nib.skip(b':') {
-                    return Err(Error::new(ErrorKind::Other, "bad line"));
-                }
-                if let Some(value) = nib.get_quoted(b'"') {
-                    let value = json_decode(value);
-                    let value = decode(value);
-                    println!("{}={}", str::from_utf8(name).unwrap(), value);
-                } else {
-                    return Err(Error::new(ErrorKind::Other, "bad line"));
-                }
-                nib.skip(b' ');
-            } else {
-                return Err(Error::new(ErrorKind::Other, "bad line"));
-            }
-        }
-    } else {
-        return Err(Error::new(ErrorKind::Other, "bad line"));
-    }
-    if !nib.skip(b']') {
-        return Err(Error::new(ErrorKind::Other, "bad line"));
-    }
-    if !nib.depleted() {
-        return Err(Error::new(ErrorKind::Other, "bad line"));
-    }
-    Ok(())
-}
-
-fn parse_tdb2() -> Result<()> {
-    let input = stdin();
-    for line in input.lock().lines() {
-        parse_ff4(&line?)?;
-    }
-    Ok(())
-}
+use tdb2::parse;
+use std::io::stdin;
 
 fn main() {
-    parse_tdb2().unwrap();
-    println!("Done");
+    let input = stdin();
+    parse(input.lock()).unwrap().iter().for_each(|t| {
+        println!("{:?}", t);
+    });
 }

src/task.rs

@@ -0,0 +1,17 @@
+use std::collections::HashMap;
+
+#[derive(Debug)]
+pub struct Task {
+    data: HashMap<String, String>,
+}
+
+impl Task {
+    /// Construct a Task from a hashmap containing named properties
+    pub fn from_data(data: HashMap<String, String>) -> Self {
+        Self { data }
+    }
+
+    pub fn description(&self) -> &str {
+        self.data.get("description").unwrap()
+    }
+}

src/tdb2/ff4.rs

@@ -0,0 +1,223 @@
+use std::str;
+use std::io::{Result, Error, ErrorKind};
+use std::collections::HashMap;
+
+use super::nibbler::Nibbler;
+use super::super::task::Task;
+
+/// Rust implementation of part of utf8_codepoint from Taskwarrior's src/utf8.cpp
+///
+/// Note that the original function will return garbage for invalid hex sequences;
+/// this panics instead.
+fn hex_to_unicode(value: &[u8]) -> String {
+    if value.len() < 4 {
+        panic!(format!("unicode escape too short -- {:?}", value));
+    }
+
+    fn nyb(c: u8) -> u16 {
+        match c {
+            b'0'...b'9' => (c - b'0') as u16,
+            b'a'...b'f' => (c - b'a' + 10) as u16,
+            b'A'...b'F' => (c - b'A' + 10) as u16,
+            _ => panic!(format!("invalid hex character {:?}", c)),
+        }
+    };
+
+    let words = [
+        nyb(value[0]) << 12 | nyb(value[1]) << 8 | nyb(value[2]) << 4 | nyb(value[3]),
+    ];
+    return String::from_utf16(&words[..]).unwrap();
+}
+
+/// Rust implementation of JSON::decode in Taskwarrior's src/JSON.cpp
+///
+/// Decode the given byte slice into a string using Taskwarrior JSON's escaping The slice is
+/// assumed to be ASCII; unicode escapes within it will be expanded.
+fn json_decode(value: &[u8]) -> String {
+    let length = value.len();
+    let mut rv = String::with_capacity(length);
+
+    let mut pos = 0;
+    while pos < length {
+        let v = value[pos];
+        if v == b'\\' {
+            pos += 1;
+            if pos == length {
+                rv.push(v as char);
+                break;
+            }
+            let v = value[pos];
+            match v {
+                b'"' | b'\\' | b'/' => rv.push(v as char),
+                b'b' => rv.push(8 as char),
+                b'f' => rv.push(12 as char),
+                b'n' => rv.push('\n' as char),
+                b'r' => rv.push('\r' as char),
+                b't' => rv.push('\t' as char),
+                b'u' => {
+                    rv.push_str(&hex_to_unicode(&value[pos + 1..]));
+                    pos += 4;
+                }
+                _ => {
+                    rv.push(b'\\' as char);
+                    rv.push(v as char);
+                }
+            }
+        } else {
+            rv.push(v as char)
+        }
+        pos += 1;
+    }
+
+    rv
+}
+
+/// Rust implementation of Task::decode in Taskwarrior's src/Task.cpp
+///
+/// Note that the docstring for the C++ function does not match the
+/// implementation!
+fn decode(value: String) -> String {
+    if let Some(_) = value.find('&') {
+        return value.replace("&open;", "[").replace("&close;", "]");
+    }
+    value
+}
+
+/// Parse an "FF4" formatted task line.  From Task::parse in Taskwarrior's src/Task.cpp.
+///
+/// While Taskwarrior supports additional formats, this is the only format supported by rask.
+pub(super) fn parse_ff4(line: &str) -> Result<Task> {
+    let mut nib = Nibbler::new(line.as_bytes());
+    let mut data = HashMap::new();
+
+    if !nib.skip(b'[') {
+        return Err(Error::new(ErrorKind::Other, "bad line"));
+    }
+    if let Some(line) = nib.get_until(b']') {
+        let mut nib = Nibbler::new(line);
+        while !nib.depleted() {
+            if let Some(name) = nib.get_until(b':') {
+                if !nib.skip(b':') {
+                    return Err(Error::new(ErrorKind::Other, "bad line"));
+                }
+                if let Some(value) = nib.get_quoted(b'"') {
+                    let value = json_decode(value);
+                    let value = decode(value);
+                    data.insert(String::from_utf8(name.to_vec()).unwrap(), value);
+                } else {
+                    return Err(Error::new(ErrorKind::Other, "bad line"));
+                }
+                nib.skip(b' ');
+            } else {
+                return Err(Error::new(ErrorKind::Other, "bad line"));
+            }
+        }
+    } else {
+        return Err(Error::new(ErrorKind::Other, "bad line"));
+    }
+    if !nib.skip(b']') {
+        return Err(Error::new(ErrorKind::Other, "bad line"));
+    }
+    if !nib.depleted() {
+        return Err(Error::new(ErrorKind::Other, "bad line"));
+    }
+    Ok(Task::from_data(data))
+}
+
+#[cfg(test)]
+mod test {
+    use super::{decode, json_decode, hex_to_unicode, parse_ff4};
+
+    #[test]
+    fn test_hex_to_unicode_digits() {
+        assert_eq!(hex_to_unicode(b"1234"), "\u{1234}");
+    }
+
+    #[test]
+    fn test_hex_to_unicode_lower() {
+        assert_eq!(hex_to_unicode(b"abcd"), "\u{abcd}");
+    }
+
+    #[test]
+    fn test_hex_to_unicode_upper() {
+        assert_eq!(hex_to_unicode(b"ABCD"), "\u{abcd}");
+    }
+
+    #[test]
+    fn test_json_decode_no_change() {
+        assert_eq!(json_decode(b"abcd"), "abcd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_quote() {
+        assert_eq!(json_decode(b"ab\\\"cd"), "ab\"cd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_backslash() {
+        assert_eq!(json_decode(b"ab\\\\cd"), "ab\\cd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_frontslash() {
+        assert_eq!(json_decode(b"ab\\/cd"), "ab/cd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_b() {
+        assert_eq!(json_decode(b"ab\\bcd"), "ab\x08cd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_f() {
+        assert_eq!(json_decode(b"ab\\fcd"), "ab\x0ccd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_n() {
+        assert_eq!(json_decode(b"ab\\ncd"), "ab\ncd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_r() {
+        assert_eq!(json_decode(b"ab\\rcd"), "ab\rcd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_t() {
+        assert_eq!(json_decode(b"ab\\tcd"), "ab\tcd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_other() {
+        assert_eq!(json_decode(b"ab\\xcd"), "ab\\xcd");
+    }
+
+    #[test]
+    fn test_json_decode_escape_eos() {
+        assert_eq!(json_decode(b"ab\\"), "ab\\");
+    }
+
+    #[test]
+    fn test_json_decode_escape_unicode() {
+        assert_eq!(json_decode(b"ab\\u1234"), "ab\u{1234}");
+    }
+
+    #[test]
+    fn test_decode_no_change() {
+        let s = "abcd &quot; efgh &".to_string();
+        assert_eq!(decode(s.clone()), s);
+    }
+
+    #[test]
+    fn test_decode_multi() {
+        let s = "abcd &open; efgh &close; &open".to_string();
+        assert_eq!(decode(s), "abcd [ efgh ] &open".to_string());
+    }
+
+    #[test]
+    fn test_parse_ff4() {
+        let task = parse_ff4("[description:\"desc\"]").unwrap();
+        assert_eq!(task.description(), "desc");
+    }
+}

src/tdb2/mod.rs

@@ -0,0 +1,14 @@
+mod nibbler;
+mod ff4;
+
+use std::io::{BufRead, Result};
+use super::task::Task;
+use self::ff4::parse_ff4;
+
+pub(super) fn parse(reader: impl BufRead) -> Result<Vec<Task>> {
+    let mut tasks = vec![];
+    for line in reader.lines() {
+        tasks.push(parse_ff4(&line?)?);
+    }
+    Ok(tasks)
+}

src/tdb2/nibbler.rs

@@ -1,3 +1,6 @@
+//! A minimal implementation of the "Nibbler" parsing utility from the Taskwarrior
+//! source.
+
 pub struct Nibbler<'a> {
     input: &'a [u8],
     cursor: usize,