From 522eef9296b2291981faceed66a5fdde52a75c13 Mon Sep 17 00:00:00 2001
From: Mathieu David <mathieudavid@mathieudavid.org>
Date: Sun, 27 Sep 2015 14:38:37 +0200
Subject: [PATCH] first implementation of the watch sub-command. #61 Needs
 refining, bug in notify made me use recursion, afraid of hitting the max
 recursion limit...

---
 Cargo.toml                  | 10 +++++--
 book-example/src/SUMMARY.md |  1 +
 src/bin/mdbook.rs           | 58 +++++++++++++++++++++++++++++++++++--
 3 files changed, 65 insertions(+), 4 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 56a9ab90..769873aa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mdbook"
-version = "0.0.1"
+version = "0.0.2"
 authors = ["Mathieu David <mathieudavid@mathieudavid.org>"]
 description = "create books from markdown files (like Gitbook)"
 documentation = "http://azerupi.github.io/mdBook/index.html"
@@ -11,6 +11,7 @@ readme = "README.md"
 build = "build.rs"
 exclude = [
     "book-example/*",
+    "src/theme/stylus",
 ]
 
 [dependencies]
@@ -22,11 +23,16 @@ pulldown-cmark = "*"
 [dev-dependencies]
 tempdir = "*"
 
+[dependencies.notify]
+notify = "*"
+optional = true
+
 [features]
-default = ["output"]
+default = ["output", "watch"]
 debug = []
 output = []
 regenerate-css = []
+watch = ["notify"]
 
 [[bin]]
 doc = false
diff --git a/book-example/src/SUMMARY.md b/book-example/src/SUMMARY.md
index a25059a7..18eb90e0 100644
--- a/book-example/src/SUMMARY.md
+++ b/book-example/src/SUMMARY.md
@@ -4,6 +4,7 @@
 - [Command Line Tool](cli/cli-tool.md)
     - [init](cli/init.md)
     - [build](cli/build.md)
+    - [watch]()
 - [Format](format/format.md)
     - [SUMMARY.md](format/summary.md)
     - [Configuration](format/config.md)
diff --git a/src/bin/mdbook.rs b/src/bin/mdbook.rs
index 027fbb85..0e63b5f1 100644
--- a/src/bin/mdbook.rs
+++ b/src/bin/mdbook.rs
@@ -1,6 +1,8 @@
 extern crate mdbook;
 #[macro_use]
 extern crate clap;
+#[cfg(feature = "watch")]
+extern crate notify;
 
 use std::env;
 use std::error::Error;
@@ -9,6 +11,11 @@ use std::path::{Path, PathBuf};
 
 use clap::{App, ArgMatches, SubCommand};
 
+#[cfg(feature = "watch")]
+use notify::Watcher;
+#[cfg(feature = "watch")]
+use std::sync::mpsc::channel;
+
 use mdbook::MDBook;
 
 const NAME: &'static str = "mdbook";
@@ -32,14 +39,16 @@ fn main() {
                         .about("Build the book from the markdown files")
                         .arg_from_usage("[dir] 'A directory for your book{n}(Defaults to Current Directory when ommitted)'"))
                     .subcommand(SubCommand::with_name("watch")
-                        .about("Watch the files for changes"))
+                        .about("Watch the files for changes")
+                        .arg_from_usage("[dir] 'A directory for your book{n}(Defaults to Current Directory when ommitted)'"))
                     .get_matches();
 
     // Check which subcomamnd the user ran...
     let res = match matches.subcommand() {
         ("init", Some(sub_matches))  => init(sub_matches),
         ("build", Some(sub_matches)) => build(sub_matches),
-        ("watch", _)                 => unimplemented!(),
+        #[cfg(feature = "watch")]
+        ("watch", Some(sub_matches)) => watch(sub_matches),
         (_, _)                       => unreachable!()
     };
 
@@ -104,6 +113,51 @@ fn build(args: &ArgMatches) -> Result<(), Box<Error>> {
     Ok(())
 }
 
+#[cfg(feature = "watch")]
+fn watch(args: &ArgMatches) -> Result<(), Box<Error>> {
+    let book_dir = get_book_dir(args);
+    let book = MDBook::new(&book_dir).read_config();
+
+    // Create a channel to receive the events.
+     let (tx, rx) = channel();
+
+     let w: Result<notify::RecommendedWatcher, notify::Error> = notify::Watcher::new(tx);
+
+     match w {
+         Ok(mut watcher) => {
+
+             watcher.watch(book.get_src()).unwrap();
+
+             loop {
+                 match rx.recv() {
+                     Ok(event) => {
+                         if let Some(path) = event.path {
+                             println!("File changed: {:?}\nBuilding book...\n", path);
+                             try!(build(args));
+                             println!("");
+                             // Hack to prevent receiving the event 4 times, probably a bug in notify
+                             return watch(args);
+                         } else {
+                             continue;
+                         }
+                     },
+                     Err(e) => {
+                         println!("An error occured: {:?}", e);
+                     }
+                 }
+             }
+
+         },
+         Err(e) => {
+             println!("Error while trying to watch the files:\n\n\t{:?}", e);
+             ::std::process::exit(0);
+         }
+     }
+
+    Ok(())
+}
+
+
 fn get_book_dir(args: &ArgMatches) -> PathBuf {
     if let Some(dir) = args.value_of("dir") {
         // Check if path is relative from current dir, or absolute...