Add tests for reader and writer

src/stream.rs

@@ -7,5 +7,6 @@ pub mod reader;
 pub mod writer;
 
 pub use event::{Event, QuoteStyle, Scalar, Tag};
+pub use read::Read;
 pub use reader::Reader;
 pub use writer::Writer;

src/stream/event.rs

@@ -27,15 +27,15 @@ pub enum Event<'a> {
 }
 
 /// A string. This is used for both keys and values.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 pub struct Scalar<'a> {
     tag: Option<Tag<'a>>,
     value: Cow<'a, str>,
     quote_style: QuoteStyle,
 }
 
 /// A conditional tag, which may be present in a [`Scalar`] key.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 pub struct Tag<'a> {
     value: Cow<'a, str>,
     quote_style: QuoteStyle,
@@ -88,21 +88,50 @@ impl<'a> Scalar<'a> {
     }
 
     /// Returns the scalar's tag. This only makes sense for keys; values completely ignore this field.
+    #[inline]
     pub fn tag(&self) -> Option<&Tag<'a>> {
         self.tag.as_ref()
     }
 
     /// Returns the scalar's value.
+    #[inline]
     pub fn value(&self) -> &str {
         &self.value
     }
 
     /// Returns the scalar's quote style.
+    #[inline]
     pub fn quote_style(&self) -> QuoteStyle {
         self.quote_style
     }
 }
 
+impl<'a> PartialEq for Scalar<'a> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        self.tag == other.tag && self.value == other.value
+    }
+}
+
+impl<'a> From<Cow<'a, str>> for Scalar<'a> {
+    fn from(value: Cow<'a, str>) -> Self {
+        // Safety: Cannot panic unless quote_style is Unquoted.
+        Scalar::new(None, value, QuoteStyle::Unspecified).unwrap()
+    }
+}
+
+impl<'a> From<&'a str> for Scalar<'a> {
+    fn from(value: &'a str) -> Self {
+        Cow::Borrowed(value).into()
+    }
+}
+
+impl<'a> From<String> for Scalar<'a> {
+    fn from(value: String) -> Self {
+        Cow::<'a, str>::Owned(value).into()
+    }
+}
+
 impl<'a> Tag<'a> {
     /// Creates a new tag. Tags values must begin with `[`, end with `]`, and be at least three
     /// characters long.
@@ -125,16 +154,49 @@ impl<'a> Tag<'a> {
     }
 
     /// Returns the tag's value. This includes the enclosing square brackets.
+    #[inline]
     pub fn value(&self) -> &str {
         &self.value
     }
 
     /// Returns the tag's quote style.
+    #[inline]
     pub fn quote_style(&self) -> QuoteStyle {
         self.quote_style
     }
 }
 
+impl<'a> PartialEq for Tag<'a> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        self.value == other.value
+    }
+}
+
+impl<'a> TryFrom<Cow<'a, str>> for Tag<'a> {
+    type Error = ();
+
+    fn try_from(value: Cow<'a, str>) -> Result<Self, Self::Error> {
+        Self::new(value, QuoteStyle::Unspecified).ok_or(())
+    }
+}
+
+impl<'a> TryFrom<&'a str> for Tag<'a> {
+    type Error = ();
+
+    fn try_from(value: &'a str) -> Result<Self, Self::Error> {
+        Cow::Borrowed(value).try_into()
+    }
+}
+
+impl<'a> TryFrom<String> for Tag<'a> {
+    type Error = ();
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Cow::<'a, str>::Owned(value).try_into()
+    }
+}
+
 fn requires_quotes(value: &str) -> bool {
     value.is_empty()
         || value.contains(|c: char| c == '{' || c == '}' || c == '"' || c.is_whitespace())

src/stream/read.rs

@@ -15,11 +15,15 @@ mod sealed {
 /// [`serde_json`]: https://docs.rs/serde_json/latest/serde_json/de/trait.Read.html
 #[allow(private_bounds)]
 pub trait Read<'a>: sealed::Sealed {
+    type Inner;
+
     fn peek_char(&mut self, i: usize) -> Result<Option<char>>;
 
     fn next_char(&mut self) -> Result<Option<char>>;
 
     fn parse_str(&mut self) -> Result<Option<Cow<'a, str>>>;
+
+    fn into_inner(self) -> Self::Inner;
 }
 
 #[derive(Debug)]
@@ -40,6 +44,8 @@ impl<R: io::Read> IoReader<R> {
 impl<R> sealed::Sealed for IoReader<R> {}
 
 impl<'a, R: io::Read> Read<'a> for IoReader<R> {
+    type Inner = io::Bytes<R>;
+
     fn peek_char(&mut self, i: usize) -> Result<Option<char>> {
         todo!()
     }
@@ -51,6 +57,10 @@ impl<'a, R: io::Read> Read<'a> for IoReader<R> {
     fn parse_str(&mut self) -> Result<Option<Cow<'a, str>>> {
         todo!()
     }
+
+    fn into_inner(self) -> Self::Inner {
+        self.bytes
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -67,6 +77,8 @@ impl<'a> SliceReader<'a> {
 impl<'a> sealed::Sealed for SliceReader<'a> {}
 
 impl<'a> Read<'a> for SliceReader<'a> {
+    type Inner = &'a [u8];
+
     fn peek_char(&mut self, i: usize) -> Result<Option<char>> {
         todo!()
     }
@@ -78,6 +90,10 @@ impl<'a> Read<'a> for SliceReader<'a> {
     fn parse_str(&mut self) -> Result<Option<Cow<'a, str>>> {
         todo!()
     }
+
+    fn into_inner(self) -> Self::Inner {
+        self.slice
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -94,6 +110,8 @@ impl<'a> StrReader<'a> {
 impl<'a> sealed::Sealed for StrReader<'a> {}
 
 impl<'a> Read<'a> for StrReader<'a> {
+    type Inner = &'a str;
+
     fn peek_char(&mut self, i: usize) -> Result<Option<char>> {
         todo!()
     }
@@ -105,4 +123,8 @@ impl<'a> Read<'a> for StrReader<'a> {
     fn parse_str(&mut self) -> Result<Option<Cow<'a, str>>> {
         todo!()
     }
+
+    fn into_inner(self) -> Self::Inner {
+        self.str
+    }
 }

src/stream/reader.rs

@@ -18,7 +18,7 @@ impl<R> Reader<R> {
 
 impl<R: io::Read> Reader<read::IoReader<R>> {
     /// Creates a KeyValues reader from an [`io::Read`].
-    /// 
+    ///
     /// This may be less efficient than creating a `Reader` from a [`&[u8]`][Self::from_slice()] or
     /// [`&str`][Self::from_str()], as those implementations do not need to buffer input.
     pub fn from_reader(reader: R) -> Self {
@@ -28,7 +28,7 @@ impl<R: io::Read> Reader<read::IoReader<R>> {
 
 impl<'a> Reader<read::SliceReader<'a>> {
     /// Creates a KeyValues reader from a `&[u8]`.
-    /// 
+    ///
     /// If the input is known to be UTF-8, use [`Reader::from_str()`] instead to prevent redundant
     /// UTF-8 validation.
     pub fn from_slice(slice: &'a [u8]) -> Self {
@@ -44,7 +44,8 @@ impl<'a> Reader<read::StrReader<'a>> {
 }
 
 impl<'a, R: read::Read<'a>> Reader<R> {
-    /// Reads the next event from the input.
+    /// Reads the next event from the input. If the end of the file has been reached, each
+    /// subsequent invocation will return [`Event::EndDocument`].
     ///
     /// # Errors
     ///
@@ -54,4 +55,73 @@ impl<'a, R: read::Read<'a>> Reader<R> {
     pub fn read(&mut self) -> Result<Event<'a>> {
         todo!()
     }
+
+    /// Unwraps the inner reader from the `Reader`.
+    pub fn into_inner(self) -> R::Inner {
+        self.inner.into_inner()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::stream::{read, Event, Reader};
+    use crate::Result;
+    use indoc::indoc;
+
+    const CHILL_ANIMALS: &str = indoc! {r#"
+        // The comments here are meant to test comment parsing.
+
+        // I think these animals are nice!
+        "ChillAnimals"
+        {
+            // These guys just seem happy to exist
+            "Animal" "Quokka"
+            
+            "Animal" 
+            // Possums are underrated, by the way
+            "Possum"
+            
+            "Animal" "Capybara" // capybaras can coexist with anything
+        }
+    "#};
+
+    fn simple<'a, R: read::Read<'a>>(reader: &mut Reader<R>) -> Result<()> {
+        // The whole document is read
+        assert_eq!(reader.read()?, Event::StartDocument);
+        assert_eq!(reader.read()?, Event::Scalar("ChillAnimals".into()));
+        assert_eq!(reader.read()?, Event::StartObject);
+        assert_eq!(reader.read()?, Event::Scalar("Animal".into()));
+        assert_eq!(reader.read()?, Event::Scalar("Quokka".into()));
+        assert_eq!(reader.read()?, Event::Scalar("Animal".into()));
+        assert_eq!(reader.read()?, Event::Scalar("Possum".into()));
+        assert_eq!(reader.read()?, Event::Scalar("Animal".into()));
+        assert_eq!(reader.read()?, Event::Scalar("Capybara".into()));
+        assert_eq!(reader.read()?, Event::EndObject);
+        assert_eq!(reader.read()?, Event::EndDocument);
+
+        // Subsequent reads should still produce EndDocument
+        assert_eq!(reader.read()?, Event::EndDocument);
+        assert_eq!(reader.read()?, Event::EndDocument);
+        assert_eq!(reader.read()?, Event::EndDocument);
+
+        Ok(())
+    }
+
+    #[test]
+    pub fn simple_str() -> Result<()> {
+        let mut reader = Reader::from_str(CHILL_ANIMALS);
+        simple(&mut reader)
+    }
+
+    #[test]
+    pub fn simple_slice() -> Result<()> {
+        let mut reader = Reader::from_slice(CHILL_ANIMALS.as_bytes());
+        simple(&mut reader)
+    }
+
+    #[test]
+    pub fn simple_reader() -> Result<()> {
+        let mut reader = Reader::from_reader(CHILL_ANIMALS.as_bytes());
+        simple(&mut reader)
+    }
 }

src/stream/writer.rs

@@ -5,24 +5,75 @@ use std::io;
 /// A low-level streaming writer that generates text from a sequence of [`Event`]s representing the
 /// KeyValues format.
 pub struct Writer<W> {
-    writer: W,
+    inner: W,
 }
 
 impl<W> Writer<W> {
     /// Creates a KeyValues writer from an [`io::Write`].
     pub fn new(writer: W) -> Self {
-        Self { writer }
+        Self { inner: writer }
     }
 }
 
 impl<W: io::Write> Writer<W> {
-    /// Writes the `event` to the output.
+    /// Writes the `event` to the output. After writing [`Event::EndDocument`], subsequent events
+    /// will be ignored.
     ///
     /// # Errors
     ///
     /// This function returns an error if an `io::Error` occurs. Note that this function does not
     /// check semantics (is this a valid document?).
-    pub fn write(event: Event<'_>) -> Result<()> {
+    pub fn write(&mut self, _event: Event<'_>) -> Result<()> {
         todo!()
     }
+
+    /// Unwraps the inner writer from the `Writer`.
+    pub fn into_inner(self) -> W {
+        self.inner
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::stream::{Event, Writer};
+    use crate::Result;
+    use indoc::indoc;
+
+    const CHILL_ANIMALS: &str = indoc! {r#"
+        "ChillAnimals"
+        {
+            "Animal" "Quokka"
+            "Animal" "Possum"
+            "Animal" "Capybara"
+        }
+    "#};
+
+    #[test]
+    fn simple() -> Result<()> {
+        let mut writer = Writer::new(Vec::new());
+
+        writer.write(Event::StartDocument)?;
+        writer.write(Event::Scalar("ChillAnimals".into()))?;
+        writer.write(Event::StartObject)?;
+        writer.write(Event::Scalar("Animal".into()))?;
+        writer.write(Event::Scalar("Quokka".into()))?;
+        writer.write(Event::Scalar("Animal".into()))?;
+        writer.write(Event::Scalar("Possum".into()))?;
+        writer.write(Event::Scalar("Animal".into()))?;
+        writer.write(Event::Scalar("Capybara".into()))?;
+        writer.write(Event::EndObject)?;
+        writer.write(Event::EndDocument)?;
+
+        // Subsequent writes after EndDocument should be ignored
+        writer.write(Event::EndDocument)?;
+        writer.write(Event::EndDocument)?;
+        writer.write(Event::StartDocument)?;
+        writer.write(Event::Scalar("yoink".into()))?;
+        writer.write(Event::EndDocument)?;
+
+        let str = String::from_utf8(writer.into_inner()).unwrap();
+        assert_eq!(str, CHILL_ANIMALS);
+
+        Ok(())
+    }
 }