lib.rs

//! dynamic_reload is a cross platform library written in [Rust](https://www.rust-lang.org) that makes it easier to do reloading of shared libraries (dll:s on windows, .so on *nix, .dylib on Mac, etc)
//! The intended use is to allow applications to reload code on the fly without closing down the application when some code changes.
//! This can be seen as a lite version of "live" coding for Rust.
//! It's worth to mention here that reloading of shared libraries isn't limited to libraries written in Rust but can be done in any language that can target shared libraries.
//! A typical scenario can look like this:
//!
//! ```ignore
//! 1. Application Foo starts.
//! 2. Foo loads the shared library Bar.
//! 3. The programmer needs to make some code changes to Bar.
//!    Instead of closing down Foo the programmer does the change, recompiles the code.
//! 4. Foo will detect that Bar has been changed on the disk,
//!    will unload the old version and load the new one.
//! ```
//! dynamic_reload library will not try to solve any stale data hanging around in Foo from Bar.
//! It is up to Foo to make sure all data has been cleaned up before Foo is reloaded.
//! Foo will be getting a callback from dynamic_reload before Bar is reloaded and that allows Foo to take needed action.
//! Then another call will be made after Bar has been reloaded to allow Foo to restore state for Bar if needed.
//!

use libloading::Library;
use notify_debouncer_mini::{notify::*,new_debouncer,DebounceEventResult, Debouncer};
use std::{
    env, fs,
    path::{Path, PathBuf},
    sync::{
        mpsc::{channel, Receiver, Sender},
        Arc,
    },
    thread,
    time::Duration,
};

pub use libloading::Symbol;
use tempfile::TempDir;

mod error;
pub use self::error::Error;

pub type Result<T> = std::result::Result<T, Error>;

/// Contains the information for a loaded library.
pub struct Lib {
    /// The actual loaded library. Refer to the libloading documentation on how to use this.
    pub lib: Library,
    /// This is the path from where the library was loaded (which may be in a temporary directory)
    pub loaded_path: PathBuf,
    /// Original location of the file. This is keep so dynamic_reload knows which file to look for
    /// updates in case the library has been changed.
    pub original_path: Option<PathBuf>,
}

/// Contains information about loaded libraries and also tracks search paths and reloading events.
pub struct DynamicReload {
    libs: Vec<Arc<Lib>>,
    watcher: Option<Debouncer<RecommendedWatcher>>,
    shadow_dir: Option<TempDir>,
    search_paths: Vec<PathBuf>,
    watch_recv: Receiver<DebounceEventResult>,
}

/// Searching for a shared library can be done in current directory, but can also be allowed to
/// search backwards.
pub enum Search {
    /// Search in current directory only
    Default,
    /// Allow searching in current directory and backwards of parent directories as well
    Backwards,
}

/// This is the states that the callback function supplied to [update](struct.DynamicReload.html#method.update) can be called with.
pub enum UpdateState {
    /// Set when a shared library is about to be reloaded. Gives the application time to save state,
    /// do clean up, etc
    Before,
    /// Called when a library has been reloaded. Allows the application to restore state.
    After,
    /// In case reloading of the library failed (broken file, etc) this will be set and allow the
    /// application to to deal with the issue.
    ReloadFailed(Error),
}

/// This is used to decide how the name used for [add_library](struct.DynamicReload.html#method.add_library) is to be handled.
#[derive(PartialEq)]
pub enum PlatformName {
    /// Leave name as is and don't do any formating.
    No,
    /// Format the name according to standard shared library name on the platform.
    ///
    /// ```ignore
    /// Windows: foobar -> foobar.dll
    /// Linux:   foobar -> libfoobar.so
    /// Mac:     foobar -> libfoobar.dylib
    /// ```
    Yes,
}

impl<'a> DynamicReload {
    ///
    /// Creates a DynamicReload object.
    ///
    /// ```search_path``` is a list of extra paths that when
    /// calling [add_library](struct.DynamicReload.html#method.add_library) the code will
    /// also try to find the shared library within those locations.
    ///
    /// ```shadow_dir``` is a location where a temporary directory will be created to
    /// keep a copy of all the shared libraries and load from there. The reason is that some
    /// operating systems locks loaded shared files which would make it impossible to update them.
    /// By having a separate directory DynamicReload will look for changes in the original path
    /// while having them loaded from another
    ///
    /// ```search``` This is to allow DynamicReload to search in parent directiors from the
    /// executable. Set this to ```Search::Backwards``` to allow that or to ```Search::Default```
    /// to only allow seach in the currenty directory of the of the executable
    ///
    /// ```debounce_duration``` is the duration that the watcher will wait after the dynamic library
    /// changed on disk, until it will cause a reload. (Multiple write calls could be made to the library
    /// until it is fully written.)
    ///
    /// # Examples
    ///
    /// ```ignore
    /// // No extra search paths, temp directory in target/debug, allow search backwards
    /// DynamicReload::new(None, Some("target/debug"), Search::Backwards, Duration::from_secs(2));
    /// ```
    ///
    /// ```ignore
    /// // "../.." extra search path, temp directory in target/debug, allow search backwards
    /// DynamicReload::new(Some(vec!["../.."]), Some("target/debug"), Search::Backwards, Duration::from_secs(2));
    /// ```
    ///
    pub fn new(
        search_paths: Option<Vec<&'a str>>,
        shadow_dir: Option<&'a str>,
        _search: Search,
        debounce_duration: Duration,
    ) -> DynamicReload {
        let (tx, rx) = channel();
        DynamicReload {
            libs: Vec::new(),
            watcher: Self::get_watcher(tx, debounce_duration),
            shadow_dir: Self::get_temp_dir(shadow_dir),
            watch_recv: rx,
            search_paths: Self::get_search_paths(search_paths),
        }
    }

    ///
    /// Add a library to be loaded and to be reloaded once updated.
    /// If PlatformName is set to Yes the input name will be formatted according
    /// to the standard way libraries looks on that platform examples:
    ///
    /// ```ignore
    /// Windows: foobar -> foobar.dll
    /// Linux:   foobar -> libfoobar.so
    /// Mac:     foobar -> libfoobar.dylib
    /// ```
    ///
    /// If set to no the given input name will be used as is. This function
    /// will also search for the file in this priority order
    ///
    /// ```ignore
    /// 1. Current directory
    /// 2. In the search paths (relative to current directory)
    /// 3. Current directory of the executable
    /// 4. Search backwards from executable if Backwards has been set DynamicReload::new
    /// ```
    /// # Examples
    ///
    /// ```ignore
    /// // Add a library named test_lib and format it according to standard platform standard.
    /// add_library("test_lib", PlatformName::Yes)
    /// ```
    /// # Safety
    /// Note taken from libloading that is used for library loading
    ///
    /// When a library is loaded, initialisation routines contained within it are executed.
    /// For the purposes of safety, the execution of these routines is conceptually the same calling an unknown foreign function and may impose arbitrary requirements on the caller for the call to be sound.
    /// Additionally, the callers of this function must also ensure that execution of the termination routines contained within
    /// the library is safe as well. These routines may be executed when the library is unloaded.
    ///
    pub unsafe fn add_library(
        &mut self,
        name: &str,
        name_format: PlatformName,
    ) -> Result<Arc<Lib>> {
        match Self::try_load_library(self, name, name_format) {
            Ok(lib) => {
                if let Some(w) = self.watcher.as_mut() {
                    if let Some(path) = lib.original_path.as_ref() {
                        let parent = path.as_path().parent().unwrap();
                        let parent_buf = if cfg!(windows) {
                            parent.to_path_buf().canonicalize().unwrap()
                        } else {
                            parent.to_path_buf()
                        };

                        let _ = w.watcher().watch(&parent_buf, RecursiveMode::NonRecursive);
                    }
                }
                // Bump the ref here as we keep one around to keep track of files that needs to be reloaded
                self.libs.push(lib.clone());
                Ok(lib)
            }
            Err(e) => Err(e),
        }
    }

    ///
    ///
    /// Needs to be called in order to handle reloads of libraries.
    ///
    /// ```update_call``` function with its data needs to be supplied to allow the application to
    /// take appropriate action depending on what needs to be done with the loaded library.
    ///
    /// ```ignore
    /// struct Plugins {
    ///     // ...
    /// }
    ///
    /// impl Plugins {
    ///    fn reload_callback(&mut self, state: UpdateState, lib: Option<&Arc<Lib>>) {
    ///        match state {
    ///            UpdateState::Before => // save state, remove from lists, etc, here
    ///            UpdateState::After => // shared lib reloaded, re-add, restore state
    ///            UpdateState::ReloadFailed(Error) => // shared lib failed to reload due to error
    ///        }
    ///    }
    /// }
    ///
    /// fn main() {
    ///     let plugins = Plugins { ... };
    ///     let mut dr = DynamicReload::new(None, Some("target/debug"), Search::Backwards, Duration::from_secs(2));
    ///     dr.add_library("test_shared", Search::Backwards);
    ///     dr.update(Plugin::reload_callback, &mut plugins);
    /// }
    /// ```
    /// # Safety
    /// Note taken from libloading that is used for library loading
    ///
    /// When a library is loaded, initialisation routines contained within it are executed.
    /// For the purposes of safety, the execution of these routines is conceptually the same calling an unknown foreign function and may impose arbitrary requirements on the caller for the call to be sound.
    /// Additionally, the callers of this function must also ensure that execution of the termination routines contained within
    /// the library is safe as well. These routines may be executed when the library is unloaded.
    ///
    pub unsafe fn update<F, T>(&mut self, update_call: &F, data: &mut T)
    where
        F: Fn(&mut T, UpdateState, Option<&Arc<Lib>>),
    {
        while let Ok(evt) = self.watch_recv.try_recv() {
            match evt {
                Ok(events) => {
                    for event in events {
                        Self::reload_libs(self, &event.path, update_call, data);
                    }
                }
                _ => (),
            }
        }
    }

    unsafe fn reload_libs<F, T>(&mut self, file_path: &Path, update_call: &F, data: &mut T)
    where
        F: Fn(&mut T, UpdateState, Option<&Arc<Lib>>),
    {
        let len = self.libs.len();
        for i in (0..len).rev() {
            if Self::should_reload(file_path, &self.libs[i]) {
                Self::reload_lib(self, i, file_path, update_call, data);
            }
        }
    }

    unsafe fn reload_lib<F, T>(
        &mut self,
        index: usize,
        file_path: &Path,
        update_call: &F,
        data: &mut T,
    ) where
        F: Fn(&mut T, UpdateState, Option<&Arc<Lib>>),
    {
        update_call(data, UpdateState::Before, Some(&self.libs[index]));
        self.remove_lib(index);

        match Self::load_library(self, file_path) {
            Ok(lib) => {
                self.libs.push(lib.clone());
                update_call(data, UpdateState::After, Some(&lib));
            }

            Err(err) => {
                update_call(data, UpdateState::ReloadFailed(err), None);
                //println!("Unable to reload lib {:?} err {:?}", file_path, err); // Removed due to move in previous line
            }
        }
    }

    unsafe fn try_load_library(&self, name: &str, name_format: PlatformName) -> Result<Arc<Lib>> {
        match Self::search_dirs(self, name, name_format) {
            Some(path) => Self::load_library(self, &path),
            None => Err(Error::Find(name.into())),
        }
    }

    unsafe fn load_library(&self, full_path: &Path) -> Result<Arc<Lib>> {
        let path;
        let original_path;

        if let Some(sd) = self.shadow_dir.as_ref() {
            path = Self::format_filename(sd.path(), full_path);
            Self::try_copy(full_path, &path)?;
            original_path = Some(full_path.to_path_buf());
        } else {
            original_path = None;
            path = full_path.to_path_buf();
        }

        Self::init_library(original_path, path)
    }

    unsafe fn init_library(org_path: Option<PathBuf>, path: PathBuf) -> Result<Arc<Lib>> {
        match Library::new(&path) {
            Ok(l) => Ok(Arc::new(Lib {
                original_path: org_path,
                loaded_path: path,
                lib: l,
            })),
            Err(e) => Err(Error::Load(e)),
        }
    }

    fn should_reload(reload_path: &Path, lib: &Lib) -> bool {
        if let Some(p) = lib.original_path.as_ref() {
            // Check if file names match.
            if reload_path.file_name() == p.file_name() {
                return true;
            }
        }

        false
    }

    fn search_dirs(&self, name: &str, name_format: PlatformName) -> Option<PathBuf> {
        let lib_name = Self::get_library_name(name, name_format);

        // 1. Search the current directory
        if let Some(path) = Self::search_current_dir(&lib_name) {
            return Some(path);
        }

        // 2. Search the relative paths
        if let Some(path) = Self::search_relative_paths(self, &lib_name) {
            return Some(path);
        }

        // 3. Search the executable dir and then go backwards
        Self::search_backwards_from_exe(&lib_name)
    }

    fn search_current_dir(name: &String) -> Option<PathBuf> {
        Self::is_file(&Path::new(name).to_path_buf())
    }

    fn search_relative_paths(&self, name: &String) -> Option<PathBuf> {
        for p in self.search_paths.iter() {
            let path = Path::new(p).join(name);
            if let Some(file) = Self::is_file(&path) {
                return Some(file);
            }
        }

        None
    }

    fn get_parent_dir(path: &Path) -> Option<PathBuf> {
        path.parent().map(|p| p.to_path_buf())
    }

    fn search_backwards_from_file(path: &Path, lib_name: &String) -> Option<PathBuf> {
        match Self::get_parent_dir(path) {
            Some(p) => {
                let new_path = Path::new(&p).join(lib_name);
                if Self::is_file(&new_path).is_some() {
                    return Some(new_path);
                }
                Self::search_backwards_from_file(&p, lib_name)
            }
            _ => None,
        }
    }

    fn search_backwards_from_exe(lib_name: &String) -> Option<PathBuf> {
        let exe_path = env::current_exe().unwrap_or_default();
        Self::search_backwards_from_file(&exe_path, lib_name)
    }

    fn get_temp_dir(shadow_dir: Option<&str>) -> Option<TempDir> {
        match shadow_dir {
            Some(dir) => match TempDir::new_in(dir) {
                Ok(td) => {
                    if !Path::exists(td.path()) {
                        // TODO: Result
                        println!("Unable to create tempdir in {}", dir);
                        None
                    } else {
                        Some(td)
                    }
                }
                Err(_er) => {
                    None
                }
            },
            _ => None,
        }
    }

    fn is_file(path: &PathBuf) -> Option<PathBuf> {
        match fs::metadata(path) {
            Ok(md) => {
                if md.is_file() {
                    Some(path.clone())
                } else {
                    None
                }
            }
            _ => None,
        }
    }

    // In some cases when a file has been set so that it's reloaded, it's actually not possible
    // to read from it directly so this code does some testing first to ensure we
    // can actually read from it (by using metadata which does a stat on the file).
    // If we can't read from it, we wait for 100 ms before we try again, if we can't
    // do it within 1 sec we give up
    //
    fn try_copy(src: &Path, dest: &Path) -> Result<()> {
        for _ in 0..10 {
            if let Ok(file) = fs::metadata(src) {
                let len = file.len();
                if len > 0 {
                    // ignore copy errors, library file might be locked by the compiler
                    if fs::copy(src, dest).is_ok() {
                        return Ok(());
                    }
                }
            }

            thread::sleep(Duration::from_millis(100));
        }

        Err(Error::CopyTimeOut(src.to_path_buf(), dest.to_path_buf()))
    }

    fn get_watcher(
        tx: Sender<DebounceEventResult>,
        debounce_duration: Duration,
    ) -> Option<Debouncer<RecommendedWatcher>> {
        match new_debouncer(debounce_duration, None, tx) {
            Ok(watcher) => Some(watcher),
            Err(e) => {
                println!(
                    "Unable to create file watcher, no dynamic reloading will be done, \
                     error: {:?}",
                    e
                );
                None
            }
        }
    }

    fn get_search_paths(search_paths: Option<Vec<&str>>) -> Vec<PathBuf> {
        match search_paths {
            Some(paths) => paths
                .iter()
                .map(|p| {
                    let path_buf = Path::new(p).to_path_buf();
                    path_buf.canonicalize().unwrap_or(path_buf)
                })
                .collect(),
            None => Vec::new(),
        }
    }

    fn get_library_name(name: &str, name_format: PlatformName) -> String {
        if name_format == PlatformName::Yes {
            Self::get_dynamiclib_name(name)
        } else {
            name.to_string()
        }
    }

    fn remove_lib(&mut self, idx: usize) {
        #[cfg(feature = "no-unload")]
        std::mem::forget(self.libs.swap_remove(idx));

        #[cfg(not(feature = "no-unload"))]
        self.libs.swap_remove(idx);
    }

    #[cfg(not(feature = "no-timestamps"))]
    fn format_filename(shadow_dir: &Path, full_path: &Path) -> PathBuf {
        let ts = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("Time went backwards");
        let filename = full_path.file_name().unwrap();
        shadow_dir.join(format!("{}_{}", ts.as_millis(), filename.to_str().unwrap()))
    }

    #[cfg(feature = "no-timestamps")]
    fn format_filename(shadow_dir: &Path, full_path: &PathBuf) -> PathBuf {
        shadow_dir.join(full_path.file_name().unwrap())
    }

    /// Formats dll name on Windows ("test_foo" -> "test_foo.dll")
    #[cfg(target_os = "windows")]
    fn get_dynamiclib_name(name: &str) -> String {
        format!("{}.dll", name)
    }

    /// Formats dll name on Mac ("test_foo" -> "libtest_foo.dylib")
    #[cfg(target_os = "macos")]
    fn get_dynamiclib_name(name: &str) -> String {
        format!("lib{}.dylib", name)
    }

    /// Formats dll name on *nix ("test_foo" -> "libtest_foo.so")
    #[cfg(any(
        target_os = "linux",
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "netbsd",
        target_os = "openbsd",
        target_os = "android"
    ))]
    fn get_dynamiclib_name(name: &str) -> String {
        format!("lib{}.so", name)
    }
}

impl PartialEq for Lib {
    fn eq(&self, other: &Lib) -> bool {
        self.original_path == other.original_path
    }

    /*
    fn ne(&self, other: &Lib) -> bool {
        self.original_path != other.original_path
    }
    */
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::env;
    use std::fs;
    use std::path::{Path, PathBuf};
    use std::sync::mpsc::channel;
    use std::sync::Arc;
    use std::thread;
    use std::time::Duration;

    #[derive(Debug, Default)]
    struct TestNotifyCallback {
        update_call_done: bool,
        after_update_done: bool,
        fail_update_done: bool,
    }

    impl TestNotifyCallback {
        fn update_call(&mut self, state: UpdateState, _lib: Option<&Arc<Lib>>) {
            match state {
                UpdateState::Before => self.update_call_done = true,
                UpdateState::After => self.after_update_done = true,
                UpdateState::ReloadFailed(_) => self.fail_update_done = true,
            }

            println!("Update state {:?}", self);
        }
    }

    fn get_test_shared_lib() -> PathBuf {
        let exe_path = env::current_exe().unwrap();
        let lib_path = exe_path.parent().unwrap().parent().unwrap();
        let lib_name = "test_shared";
        Path::new(&lib_path).join(DynamicReload::get_dynamiclib_name(lib_name))
    }

    #[test]
    fn test_search_paths_none() {
        assert_eq!(DynamicReload::get_search_paths(None).len(), 0);
    }

    #[test]
    fn test_search_paths_some() {
        assert_eq!(
            DynamicReload::get_search_paths(Some(vec!["test", "test"])).len(),
            2
        );
    }

    #[test]
    fn test_get_watcher() {
        let (tx, _) = channel();
        // We expect this to always work
        assert!(DynamicReload::get_watcher(tx, Duration::from_secs(2)).is_some());
    }

    #[test]
    fn test_get_temp_dir_fail() {
        assert!(DynamicReload::get_temp_dir(Some("_no_such_dir")).is_none());
    }

    #[test]
    fn test_get_temp_dir_none() {
        assert!(DynamicReload::get_temp_dir(None).is_none());
    }

    #[test]
    fn test_get_temp_dir_ok() {
        assert!(DynamicReload::get_temp_dir(Some("")).is_some());
    }

    #[test]
    fn test_is_file_fail() {
        assert!(
            DynamicReload::is_file(&Path::new("haz_no_file_with_this_name").to_path_buf())
                .is_none()
        );
    }

    #[test]
    fn test_is_file_ok() {
        assert!(DynamicReload::is_file(&env::current_exe().unwrap()).is_some());
    }

    #[test]
    #[cfg(target_os = "macos")]
    fn test_get_library_name_mac() {
        assert_eq!(
            DynamicReload::get_library_name("foobar", PlatformName::Yes),
            "libfoobar.dylib"
        );
    }

    #[test]
    fn test_get_library_name() {
        assert_eq!(
            DynamicReload::get_library_name("foobar", PlatformName::No),
            "foobar"
        );
    }

    #[test]
    fn test_search_backwards_from_file_ok() {
        // While this relays on having a Cargo project, it should be fine
        assert!(DynamicReload::search_backwards_from_exe(&"Cargo.toml".to_string()).is_some());
    }

    #[test]
    fn test_search_backwards_from_file_fail() {
        assert!(DynamicReload::search_backwards_from_exe(&"_no_such_file".to_string()).is_none());
    }

    #[test]
    fn test_add_library_fail() {
        let mut dr = DynamicReload::new(None, None, Search::Default, Duration::from_secs(2));
        unsafe {
            assert!(dr
                .add_library("wont_find_this_lib", PlatformName::No)
                .is_err());
        }
    }

    #[test]
    fn test_add_shared_lib_ok() {
        let mut dr = DynamicReload::new(None, None, Search::Default, Duration::from_secs(2));
        unsafe {
            assert!(dr.add_library("test_shared", PlatformName::Yes).is_ok());
        }
    }

    #[test]
    fn test_add_shared_lib_search_paths() {
        let mut dr = DynamicReload::new(
            Some(vec!["../..", "../test"]),
            None,
            Search::Default,
            Duration::from_secs(2),
        );
        unsafe {
            assert!(dr.add_library("test_shared", PlatformName::Yes).is_ok());
        }
    }

    #[test]
    fn test_add_shared_lib_fail_load() {
        let mut dr = DynamicReload::new(None, None, Search::Default, Duration::from_secs(2));
        unsafe {
            assert!(dr.add_library("Cargo.toml", PlatformName::No).is_err());
        }
    }

    #[test]
    fn test_add_shared_shadow_dir_ok() {
        let dr = DynamicReload::new(
            None,
            Some("target/debug"),
            Search::Default,
            Duration::from_secs(2),
        );
        assert!(dr.shadow_dir.is_some());
    }

    #[test]
    fn test_add_shared_string_arg_ok() {
        let shadow_dir_string = "target/debug".to_owned();
        let dr = DynamicReload::new(
            None,
            Some(&shadow_dir_string),
            Search::Default,
            Duration::from_secs(2),
        );
        assert!(dr.shadow_dir.is_some());
    }

    #[test]
    fn test_add_shared_lib_search_paths_strings() {
        let path1 = "../..".to_owned();
        let path2 = "../test".to_owned();
        let mut dr = DynamicReload::new(
            Some(vec![&path1, &path2]),
            None,
            Search::Default,
            Duration::from_secs(2),
        );
        unsafe {
            assert!(dr.add_library("test_shared", PlatformName::Yes).is_ok());
        }
    }

    #[test]
    fn test_add_shared_update() {
        let mut notify_callback = TestNotifyCallback::default();
        let target_path = get_test_shared_lib();

        let mut dest_path = Path::new(&target_path).to_path_buf();

        let mut dr = DynamicReload::new(
            None,
            Some("target/debug"),
            Search::Default,
            Duration::from_secs(1),
        );

        dest_path.set_file_name("test_file");

        fs::copy(&target_path, &dest_path).unwrap();

        unsafe {
            assert!(dr.add_library("test_shared", PlatformName::Yes).is_ok());
        }

        for i in 0..10 {
            unsafe {
                dr.update(&TestNotifyCallback::update_call, &mut notify_callback);
            }

            if i == 2 {
                fs::copy(&dest_path, &target_path).unwrap();
            }

            thread::sleep(Duration::from_millis(200));
        }

        assert!(notify_callback.update_call_done);
        assert!(notify_callback.after_update_done);
    }

    #[test]
    fn test_add_shared_update_fail_after() {
        let mut notify_callback = TestNotifyCallback::default();
        let target_path = get_test_shared_lib();
        let test_file = DynamicReload::get_dynamiclib_name("test_file_2");
        let mut dest_path = Path::new(&target_path).to_path_buf();

        let mut dr = DynamicReload::new(
            Some(vec!["target/debug"]),
            Some("target/debug"),
            Search::Default,
            Duration::from_secs(1),
        );

        assert!(dr.shadow_dir.is_some());

        dest_path.set_file_name(&test_file);

        DynamicReload::try_copy(&target_path, &dest_path).unwrap();

        // Wait a while before open the file. Not sure why this is needed.
        thread::sleep(Duration::from_millis(2000));

        unsafe {
            assert!(dr.add_library(&test_file, PlatformName::No).is_ok());
        }

        for i in 0..10 {
            println!("update {}", i);
            unsafe {
                dr.update(&TestNotifyCallback::update_call, &mut notify_callback);
            }

            if i == 2 {
                // Copy a non-shared lib to test the lib handles a broken "lib"
                fs::copy("Cargo.toml", &dest_path).unwrap();
            }

            thread::sleep(Duration::from_millis(200));
        }

        assert_eq!(notify_callback.update_call_done, true);
        assert_eq!(notify_callback.after_update_done, false);
        assert_eq!(notify_callback.fail_update_done, true);
    }

    #[test]
    fn test_lib_equals_true() {
        let mut dr = DynamicReload::new(None, None, Search::Default, Duration::from_secs(2));
        let lib = unsafe { dr.add_library("test_shared", PlatformName::Yes).unwrap() };
        let lib2 = lib.clone();
        assert!(lib == lib2);
    }

    #[test]
    fn test_lib_equals_false() {
        let mut dr = DynamicReload::new(
            Some(vec!["target/debug"]),
            Some("target/debug"),
            Search::Default,
            Duration::from_secs(2),
        );
        let target_path = get_test_shared_lib();

        let test_file = DynamicReload::get_dynamiclib_name("test_file_2");
        let mut dest_path = Path::new(&target_path).to_path_buf();

        dest_path.set_file_name(&test_file);

        let _ = DynamicReload::try_copy(&target_path, &dest_path);
        thread::sleep(Duration::from_millis(100));

        let lib0 = unsafe { dr.add_library(&test_file, PlatformName::No).unwrap() };
        let lib1 = unsafe { dr.add_library("test_shared", PlatformName::Yes).unwrap() };

        assert!(lib0 != lib1);
    }
}