1 files changed, 265 insertions, 0 deletions
diff --git a/vendor/mdbook/src/renderer/mod.rs b/vendor/mdbook/src/renderer/mod.rs
new file mode 100644
index 000000000..15465fbce
--- /dev/null
+++ b/vendor/mdbook/src/renderer/mod.rs
@@ -0,0 +1,265 @@
+//! `mdbook`'s low level rendering interface.
+//!
+//! # Note
+//!
+//! You usually don't need to work with this module directly. If you want to
+//! implement your own backend, then check out the [For Developers] section of
+//! the user guide.
+//!
+//! The definition for [RenderContext] may be useful though.
+//!
+//! [For Developers]: https://rust-lang.github.io/mdBook/for_developers/index.html
+//! [RenderContext]: struct.RenderContext.html
+
+pub use self::html_handlebars::HtmlHandlebars;
+pub use self::markdown_renderer::MarkdownRenderer;
+
+mod html_handlebars;
+mod markdown_renderer;
+
+use shlex::Shlex;
+use std::collections::HashMap;
+use std::fs;
+use std::io::{self, ErrorKind, Read};
+use std::path::{Path, PathBuf};
+use std::process::{Command, Stdio};
+
+use crate::book::Book;
+use crate::config::Config;
+use crate::errors::*;
+use toml::Value;
+
+use serde::{Deserialize, Serialize};
+
+/// An arbitrary `mdbook` backend.
+///
+/// Although it's quite possible for you to import `mdbook` as a library and
+/// provide your own renderer, there are two main renderer implementations that
+/// 99% of users will ever use:
+///
+/// - [`HtmlHandlebars`] - the built-in HTML renderer
+/// - [`CmdRenderer`] - a generic renderer which shells out to a program to do the
+///   actual rendering
+pub trait Renderer {
+    /// The `Renderer`'s name.
+    fn name(&self) -> &str;
+
+    /// Invoke the `Renderer`, passing in all the necessary information for
+    /// describing a book.
+    fn render(&self, ctx: &RenderContext) -> Result<()>;
+}
+
+/// The context provided to all renderers.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct RenderContext {
+    /// Which version of `mdbook` did this come from (as written in `mdbook`'s
+    /// `Cargo.toml`). Useful if you know the renderer is only compatible with
+    /// certain versions of `mdbook`.
+    pub version: String,
+    /// The book's root directory.
+    pub root: PathBuf,
+    /// A loaded representation of the book itself.
+    pub book: Book,
+    /// The loaded configuration file.
+    pub config: Config,
+    /// Where the renderer *must* put any build artefacts generated. To allow
+    /// renderers to cache intermediate results, this directory is not
+    /// guaranteed to be empty or even exist.
+    pub destination: PathBuf,
+    #[serde(skip)]
+    pub(crate) chapter_titles: HashMap<PathBuf, String>,
+    #[serde(skip)]
+    __non_exhaustive: (),
+}
+
+impl RenderContext {
+    /// Create a new `RenderContext`.
+    pub fn new<P, Q>(root: P, book: Book, config: Config, destination: Q) -> RenderContext
+    where
+        P: Into<PathBuf>,
+        Q: Into<PathBuf>,
+    {
+        RenderContext {
+            book,
+            config,
+            version: crate::MDBOOK_VERSION.to_string(),
+            root: root.into(),
+            destination: destination.into(),
+            chapter_titles: HashMap::new(),
+            __non_exhaustive: (),
+        }
+    }
+
+    /// Get the source directory's (absolute) path on disk.
+    pub fn source_dir(&self) -> PathBuf {
+        self.root.join(&self.config.book.src)
+    }
+
+    /// Load a `RenderContext` from its JSON representation.
+    pub fn from_json<R: Read>(reader: R) -> Result<RenderContext> {
+        serde_json::from_reader(reader).with_context(|| "Unable to deserialize the `RenderContext`")
+    }
+}
+
+/// A generic renderer which will shell out to an arbitrary executable.
+///
+/// # Rendering Protocol
+///
+/// When the renderer's `render()` method is invoked, `CmdRenderer` will spawn
+/// the `cmd` as a subprocess. The `RenderContext` is passed to the subprocess
+/// as a JSON string (using `serde_json`).
+///
+/// > **Note:** The command used doesn't necessarily need to be a single
+/// > executable (i.e. `/path/to/renderer`). The `cmd` string lets you pass
+/// > in command line arguments, so there's no reason why it couldn't be
+/// > `python /path/to/renderer --from mdbook --to epub`.
+///
+/// Anything the subprocess writes to `stdin` or `stdout` will be passed through
+/// to the user. While this gives the renderer maximum flexibility to output
+/// whatever it wants, to avoid spamming users it is recommended to avoid
+/// unnecessary output.
+///
+/// To help choose the appropriate output level, the `RUST_LOG` environment
+/// variable will be passed through to the subprocess, if set.
+///
+/// If the subprocess wishes to indicate that rendering failed, it should exit
+/// with a non-zero return code.
+#[derive(Debug, Clone, PartialEq)]
+pub struct CmdRenderer {
+    name: String,
+    cmd: String,
+}
+
+impl CmdRenderer {
+    /// Create a new `CmdRenderer` which will invoke the provided `cmd` string.
+    pub fn new(name: String, cmd: String) -> CmdRenderer {
+        CmdRenderer { name, cmd }
+    }
+
+    fn compose_command(&self, root: &Path, destination: &Path) -> Result<Command> {
+        let mut words = Shlex::new(&self.cmd);
+        let exe = match words.next() {
+            Some(e) => PathBuf::from(e),
+            None => bail!("Command string was empty"),
+        };
+
+        let exe = if exe.components().count() == 1 {
+            // Search PATH for the executable.
+            exe
+        } else {
+            // Relative paths are preferred to be relative to the book root.
+            let abs_exe = root.join(&exe);
+            if abs_exe.exists() {
+                abs_exe
+            } else {
+                // Historically paths were relative to the destination, but
+                // this is not the preferred way.
+                let legacy_path = destination.join(&exe);
+                if legacy_path.exists() {
+                    warn!(
+                        "Renderer command `{}` uses a path relative to the \
+                        renderer output directory `{}`. This was previously \
+                        accepted, but has been deprecated. Relative executable \
+                        paths should be relative to the book root.",
+                        exe.display(),
+                        destination.display()
+                    );
+                    legacy_path
+                } else {
+                    // Let this bubble through to later be handled by
+                    // handle_render_command_error.
+                    abs_exe
+                }
+            }
+        };
+
+        let mut cmd = Command::new(exe);
+
+        for arg in words {
+            cmd.arg(arg);
+        }
+
+        Ok(cmd)
+    }
+}
+
+impl CmdRenderer {
+    fn handle_render_command_error(&self, ctx: &RenderContext, error: io::Error) -> Result<()> {
+        if let ErrorKind::NotFound = error.kind() {
+            // Look for "output.{self.name}.optional".
+            // If it exists and is true, treat this as a warning.
+            // Otherwise, fail the build.
+
+            let optional_key = format!("output.{}.optional", self.name);
+
+            let is_optional = match ctx.config.get(&optional_key) {
+                Some(Value::Boolean(value)) => *value,
+                _ => false,
+            };
+
+            if is_optional {
+                warn!(
+                    "The command `{}` for backend `{}` was not found, \
+                    but was marked as optional.",
+                    self.cmd, self.name
+                );
+                return Ok(());
+            } else {
+                error!(
+                    "The command `{0}` wasn't found, is the \"{1}\" backend installed? \
+                    If you want to ignore this error when the \"{1}\" backend is not installed, \
+                    set `optional = true` in the `[output.{1}]` section of the book.toml configuration file.",
+                    self.cmd, self.name
+                );
+            }
+        }
+        Err(error).with_context(|| "Unable to start the backend")?
+    }
+}
+
+impl Renderer for CmdRenderer {
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn render(&self, ctx: &RenderContext) -> Result<()> {
+        info!("Invoking the \"{}\" renderer", self.name);
+
+        let _ = fs::create_dir_all(&ctx.destination);
+
+        let mut child = match self
+            .compose_command(&ctx.root, &ctx.destination)?
+            .stdin(Stdio::piped())
+            .stdout(Stdio::inherit())
+            .stderr(Stdio::inherit())
+            .current_dir(&ctx.destination)
+            .spawn()
+        {
+            Ok(c) => c,
+            Err(e) => return self.handle_render_command_error(ctx, e),
+        };
+
+        let mut stdin = child.stdin.take().expect("Child has stdin");
+        if let Err(e) = serde_json::to_writer(&mut stdin, &ctx) {
+            // Looks like the backend hung up before we could finish
+            // sending it the render context. Log the error and keep going
+            warn!("Error writing the RenderContext to the backend, {}", e);
+        }
+
+        // explicitly close the `stdin` file handle
+        drop(stdin);
+
+        let status = child
+            .wait()
+            .with_context(|| "Error waiting for the backend to complete")?;
+
+        trace!("{} exited with output: {:?}", self.cmd, status);
+
+        if !status.success() {
+            error!("Renderer exited with non-zero return code.");
+            bail!("The \"{}\" renderer failed", self.name);
+        } else {
+            Ok(())
+        }
+    }
+}