From 7ecf5f540b0b224119896dcb42bb4a5daedb18ed Mon Sep 17 00:00:00 2001
From: Alexandre Bury <alexandre.bury@gmail.com>
Date: Wed, 10 Jan 2018 13:54:15 +0100
Subject: [PATCH] Add markup::{Markup, StyledString}

---
 src/utils/markup/markdown.rs | 15 +++++++-
 src/utils/markup/mod.rs      | 68 ++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/src/utils/markup/markdown.rs b/src/utils/markup/markdown.rs
index d34edcf..c49fdea 100644
--- a/src/utils/markup/markdown.rs
+++ b/src/utils/markup/markdown.rs
@@ -9,7 +9,7 @@ use std::borrow::Cow;
 use theme::{Effect, Style};
 use utils::lines::spans::Span;
 
-/// Parse markdown string into spans of styled text.
+/// Iterator that parse a markdown text and outputs styled spans.
 pub struct Parser<'a> {
     first: bool,
     stack: Vec<Style>,
@@ -118,6 +118,19 @@ pub fn parse<'a>(input: &'a str) -> Vec<Span<'a>> {
     Parser::new(input).collect()
 }
 
+/// `Markup` trait implementation for markdown text.
+///
+/// Requires the `markdown` feature.
+pub struct Markdown;
+
+impl super::Markup for Markdown {
+    type Error = ();
+
+    fn parse<'a>(input: &'a str) -> Result<Vec<Span<'a>>, Self::Error> {
+        Ok(parse(input))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/utils/markup/mod.rs b/src/utils/markup/mod.rs
index 51dc7a0..e280cc1 100644
--- a/src/utils/markup/mod.rs
+++ b/src/utils/markup/mod.rs
@@ -4,3 +4,71 @@
 
 #[cfg(feature = "markdown")]
 pub mod markdown;
+
+#[cfg(feature = "markdown")]
+pub use self::markdown::Markdown;
+use owning_ref::OwningHandle;
+use owning_ref::StringRef;
+use std::marker::PhantomData;
+use utils::lines::spans::Span;
+
+/// Trait for parsing text into styled spans.
+pub trait Markup {
+    /// Possible error happening when parsing.
+    type Error;
+
+    /// Parses text and return the styled spans.
+    fn parse<'a>(input: &'a str) -> Result<Vec<Span<'a>>, Self::Error>;
+}
+
+type StyledHandle = OwningHandle<StringRef, Vec<Span<'static>>>;
+
+/// A String that parses a markup language.
+pub struct StyledString<M> {
+    content: StyledHandle,
+    _phantom: PhantomData<M>,
+}
+
+impl<M> StyledString<M>
+where
+    M: Markup,
+{
+    fn make_handle<S: Into<String>>(
+        content: S
+    ) -> Result<StyledHandle, M::Error> {
+        let content = content.into();
+        OwningHandle::try_new(StringRef::new(content), |input| {
+            M::parse(unsafe { &*input })
+        })
+    }
+
+    /// Creates a new styled string, parsing the given content.
+    pub fn new<S>(content: S) -> Result<Self, M::Error>
+    where
+        S: Into<String>,
+    {
+        let content = Self::make_handle(content)?;
+        Ok(StyledString {
+            content,
+            _phantom: PhantomData,
+        })
+    }
+
+    /// Sets the content of this string.
+    ///
+    /// The content will be parsed; if an error is found,
+    /// it will be returned here (and the content will be unchanged).
+    pub fn set_content<S>(&mut self, content: S) -> Result<(), M::Error>
+    where
+        S: Into<String>,
+    {
+        self.content = Self::make_handle(content)?;
+
+        Ok(())
+    }
+
+    /// Gives access to the parsed styled spans.
+    pub fn spans<'a>(&'a self) -> &'a [Span<'a>] {
+        &self.content
+    }
+}