ggez 0.10.0

//! A cross-platform interface to the filesystem.
//!
//! This module provides access to files in specific places:
//!
//! * The `resources/` subdirectory in the same directory as the
//!   program executable, if any,
//! * The `resources.zip` file in the same
//!   directory as the program executable, if any,
//! * The root folder of the  game's "save" directory which is in a
//!   platform-dependent location,
//!   such as `~/.local/share/<gameid>/` on Linux.  The `gameid`
//!   is the the string passed to
//!   [`ContextBuilder::new()`](../struct.ContextBuilder.html#method.new).
//!   Some platforms such as Windows also incorporate the `author` string into
//!   the path.
//!
//! These locations will be searched for files in the order listed, and the first file
//! found used.  That allows game assets to be easily distributed as an archive
//! file, but locally overridden for testing or modding simply by putting
//! altered copies of them in the game's `resources/` directory.  It
//! is loosely based off of the `PhysicsFS` library.
//!
//! See the source of the [`files` example](https://github.com/ggez/ggez/blob/master/examples/files.rs) for more details.
//!
//! The names of `resources/` and `resources.zip` can be changed with the methods
//! [`resources_dir_name`](../struct.ContextBuilder.html#method.resources_dir_name)
//! and
//! [`resources_zip_name`](../struct.ContextBuilder.html#method.resources_zip_name)
//!  of `ContextBuilder`.
//!
//! Note that the file lookups WILL follow symlinks!  This module's
//! directory isolation is intended for convenience, not security, so
//! don't assume it will be secure.

use crate::{
    conf,
    vfs::{self, OverlayFS, VFS},
    GameError, GameResult,
};
use directories::ProjectDirs;
use std::{
    env,
    io::{self, Read},
    path,
    sync::{Arc, RwLock},
};

pub use crate::vfs::OpenOptions;

const CONFIG_NAME: &str = "/conf.toml";

/// A structure that contains the filesystem state and cache.
#[derive(Clone, Debug)]
pub struct Filesystem {
    vfs: Arc<RwLock<vfs::OverlayFS>>,
    resources_dir: path::PathBuf,
    zip_dir: path::PathBuf,
    user_config_dir: path::PathBuf,
    user_data_dir: path::PathBuf,
}

/// Represents a file, either in the filesystem, or in the resources zip file,
/// or whatever.
#[derive(Debug)]
pub struct File(Box<dyn vfs::VFile>);

impl io::Read for File {
    #[inline]
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        self.0.read(buf)
    }

    #[inline]
    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
        self.0.read_exact(buf)
    }

    #[inline]
    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
        self.0.read_to_end(buf)
    }

    #[inline]
    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
        self.0.read_to_string(buf)
    }
}

impl io::Write for File {
    #[inline]
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        self.0.write(buf)
    }

    #[inline]
    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
        self.0.write_all(buf)
    }

    #[inline]
    fn flush(&mut self) -> io::Result<()> {
        self.0.flush()
    }
}

impl io::Seek for File {
    #[inline]
    fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
        self.0.seek(pos)
    }

    #[inline]
    fn stream_position(&mut self) -> io::Result<u64> {
        self.0.stream_position()
    }
}

impl Filesystem {
    /// Create a new `Filesystem` instance, using the given `id` and (on
    /// some platforms) the `author` as a portion of the user
    /// directory path.  This function is called automatically by
    /// ggez, the end user should never need to call it.
    pub fn new<P: AsRef<path::Path>, Q: AsRef<path::Path>>(
        id: &str,
        author: &str,
        resources_dir_name: P,
        resources_zip_name: Q,
    ) -> GameResult<Filesystem> {
        Self::_new(
            id,
            author,
            resources_dir_name.as_ref(),
            resources_zip_name.as_ref(),
        )
    }

    /// Actual implementation of `new`, without generics.
    fn _new(
        id: &str,
        author: &str,
        resources_dir_name: &path::Path,
        resources_zip_name: &path::Path,
    ) -> GameResult<Filesystem> {
        let mut root_path = env::current_exe()?;

        // Ditch the filename (if any)
        if root_path.file_name().is_some() {
            let _ = root_path.pop();
        }

        // Set up VFS to merge resource path, root path, and zip path.
        let mut overlay = vfs::OverlayFS::new();

        let mut resources_path;
        let mut resources_zip_path;
        let user_data_path;
        let user_config_path;

        let project_dirs = match ProjectDirs::from("", author, id) {
            Some(dirs) => dirs,
            None => {
                return Err(GameError::FilesystemError(String::from(
                    "No valid home directory path could be retrieved.",
                )));
            }
        };

        // <game exe root>/resources/
        {
            resources_path = root_path.clone();
            resources_path.push(resources_dir_name);
            trace!("Resources path: {resources_path:?}");
            let physfs = vfs::PhysicalFS::new(&resources_path, true);
            overlay.push_back(Box::new(physfs));
        }

        // <root>/resources.zip
        {
            resources_zip_path = root_path;
            resources_zip_path.push(resources_zip_name);
            if resources_zip_path.exists() {
                trace!("Resources zip file: {resources_zip_path:?}");
                let zipfs = vfs::ZipFS::new(&resources_zip_path)?;
                overlay.push_back(Box::new(zipfs));
            } else {
                trace!("No resources zip file found");
            }
        }

        // Per-user data dir,
        // ~/.local/share/whatever/
        {
            user_data_path = project_dirs.data_local_dir();
            trace!("User-local data path: {user_data_path:?}");
            let physfs = vfs::PhysicalFS::new(user_data_path, true);
            overlay.push_back(Box::new(physfs));
        }

        // Writeable local dir, ~/.config/whatever/
        // Save game dir is read-write
        {
            user_config_path = project_dirs.config_dir();
            trace!("User-local configuration path: {user_config_path:?}");
            let physfs = vfs::PhysicalFS::new(user_config_path, false);
            overlay.push_back(Box::new(physfs));
        }

        let fs = Filesystem {
            vfs: Arc::new(RwLock::new(overlay)),
            resources_dir: resources_path,
            zip_dir: resources_zip_path,
            user_config_dir: user_config_path.to_path_buf(),
            user_data_dir: user_data_path.to_path_buf(),
        };

        Ok(fs)
    }

    fn vfs(&self) -> impl std::ops::Deref<Target = OverlayFS> + '_ {
        self.vfs.read().unwrap()
    }

    fn vfs_mut(&self) -> impl std::ops::DerefMut<Target = OverlayFS> + '_ {
        self.vfs.write().unwrap()
    }

    /// Opens the given `path` and returns the resulting `File`
    /// in read-only mode.
    pub fn open<P: AsRef<path::Path>>(&self, path: P) -> GameResult<File> {
        self.vfs().open(path.as_ref()).map(File)
    }

    /// Opens a file in the user directory with the given
    /// [`filesystem::OpenOptions`](struct.OpenOptions.html).
    /// Note that even if you open a file read-write, it can only
    /// write to files in the "user" directory.
    pub fn open_options<P: AsRef<path::Path>>(
        &self,
        path: P,
        options: OpenOptions,
    ) -> GameResult<File> {
        self.vfs()
            .open_options(path.as_ref(), options)
            .map(File)
            .map_err(|e| {
                GameError::ResourceLoadError(format!(
                    "Tried to open {:?} but got error: {:?}",
                    path.as_ref(),
                    e
                ))
            })
    }

    /// Creates a new file in the user directory and opens it
    /// to be written to, truncating it if it already exists.
    pub fn create<P: AsRef<path::Path>>(&self, path: P) -> GameResult<File> {
        self.vfs().create(path.as_ref()).map(File)
    }

    /// Reads the whole content of a file to a `Vec`.
    pub fn read<P: AsRef<path::Path>>(&self, path: P) -> GameResult<Vec<u8>> {
        let mut file = self.open(path)?;
        let mut buf = Vec::new();
        let _ = file.read_to_end(&mut buf)?;
        Ok(buf)
    }

    /// Reads the whole content of a file to a `String`.
    pub fn read_to_string<P: AsRef<path::Path>>(&self, path: P) -> GameResult<String> {
        let mut file = self.open(path)?;
        let mut buf = String::new();
        let _ = file.read_to_string(&mut buf)?;
        Ok(buf)
    }

    /// Create an empty directory in the user dir
    /// with the given name.  Any parents to that directory
    /// that do not exist will be created.
    pub fn create_dir<P: AsRef<path::Path>>(&self, path: P) -> GameResult {
        self.vfs().mkdir(path.as_ref())
    }

    /// Deletes the specified file in the user dir.
    pub fn delete<P: AsRef<path::Path>>(&self, path: P) -> GameResult {
        self.vfs().rm(path.as_ref())
    }

    /// Deletes the specified directory in the user dir,
    /// and all its contents!
    pub fn delete_dir<P: AsRef<path::Path>>(&self, path: P) -> GameResult {
        self.vfs().rmrf(path.as_ref())
    }

    /// Check whether a file or directory exists.
    pub fn exists<P: AsRef<path::Path>>(&self, path: P) -> bool {
        self.vfs().exists(path.as_ref())
    }

    /// Check whether a path points at a file.
    pub fn is_file<P: AsRef<path::Path>>(&self, path: P) -> bool {
        self.vfs()
            .metadata(path.as_ref())
            .map(|m| m.is_file())
            .unwrap_or(false)
    }

    /// Check whether a path points at a directory.
    pub fn is_dir<P: AsRef<path::Path>>(&self, path: P) -> bool {
        self.vfs()
            .metadata(path.as_ref())
            .map(|m| m.is_dir())
            .unwrap_or(false)
    }

    /// Returns a list of all files and directories in the resource directory,
    /// in no particular order.
    ///
    /// Lists the base directory if an empty path is given.
    pub fn read_dir<P: AsRef<path::Path>>(&self, path: P) -> GameResult<Vec<path::PathBuf>> {
        let mut paths = Vec::new();
        self.vfs().read_dir(path.as_ref(), &mut paths)?;
        Ok(paths)
    }

    fn write_to_string(&self) -> String {
        use std::fmt::Write;
        let mut s = String::new();
        for vfs in self.vfs().roots() {
            write!(s, "Source {vfs:?}").expect("Could not write to string; should never happen?");
            match self.read_dir("/") {
                Ok(files) => {
                    for itm in files {
                        write!(s, "  {itm:?}")
                            .expect("Could not write to string; should never happen?");
                    }
                }
                Err(e) => write!(s, " Could not read source: {e:?}")
                    .expect("Could not write to string; should never happen?"),
            }
        }
        s
    }

    /// Prints the contents of all data directories
    /// to standard output.  Useful for debugging.
    pub fn print_all(&self) {
        println!("{}", self.write_to_string());
    }

    /// Outputs the contents of all data directories,
    /// using the "info" log level of the [`log`](https://docs.rs/log/) crate.
    /// Useful for debugging.
    pub fn log_all(&self) {
        info!("{}", self.write_to_string());
    }

    /// Adds the given (absolute) path to the list of directories
    /// it will search to look for resources.
    ///
    /// You probably shouldn't use this in the general case, since it is
    /// harder than it looks to make it bulletproof across platforms.
    /// But it can be very nice for debugging and dev purposes, such as
    /// by pushing `$CARGO_MANIFEST_DIR/resources` to it
    pub fn mount(&self, path: &path::Path, readonly: bool) {
        let physfs = vfs::PhysicalFS::new(path, readonly);
        trace!("Mounting new path: {physfs:?}");
        self.vfs_mut().push_back(Box::new(physfs));
    }

    /// Adds any object that implements Read + Seek as a zip file.
    ///
    /// Note: This is not intended for system files for the same reasons as
    /// for `.mount()`. Rather, it can be used to read zip files from sources
    /// such as `std::io::Cursor::new(includes_bytes!(...))` in order to embed
    /// resources into the game's executable.
    pub fn add_zip_file<R: io::Read + io::Seek + Send + 'static>(&self, reader: R) -> GameResult {
        let zipfs = vfs::ZipFS::from_read(reader)?;
        trace!("Adding zip file from reader");
        self.vfs_mut().push_back(Box::new(zipfs));
        Ok(())
    }

    /// Looks for a file named `/conf.toml` in any resource directory and
    /// loads it if it finds it.
    /// If it can't read it for some reason, returns an error.
    pub fn read_config(&self) -> GameResult<conf::Conf> {
        let conf_path = path::Path::new(CONFIG_NAME);
        if self.is_file(conf_path) {
            let mut file = self.open(conf_path)?;
            let c = conf::Conf::from_toml_file(&mut file)?;
            Ok(c)
        } else {
            Err(GameError::ConfigError(String::from(
                "Config file not found",
            )))
        }
    }

    /// Takes a `Conf` object and saves it to the user directory,
    /// overwriting any file already there.
    pub fn write_config(&self, conf: &conf::Conf) -> GameResult {
        let conf_path = path::Path::new(CONFIG_NAME);
        let mut file = self.create(conf_path)?;
        conf.to_toml_file(&mut file)?;
        if self.is_file(conf_path) {
            Ok(())
        } else {
            Err(GameError::ConfigError(format!(
                "Failed to write config file at {}",
                conf_path.to_string_lossy()
            )))
        }
    }

    /// Returns the full path to the resource directory
    /// (even if it doesn't exist)
    pub fn resources_dir(&self) -> &path::Path {
        &self.resources_dir
    }

    /// Get a reference to the filesystem's zip dir.
    pub fn zip_dir(&self) -> &path::Path {
        &self.zip_dir
    }

    /// Return the full path to the user config directory.
    pub fn user_config_dir(&self) -> &path::Path {
        &self.user_config_dir
    }

    /// Return the full path to the user data directory.
    pub fn user_data_dir(&self) -> &path::Path {
        &self.user_data_dir
    }
}

#[cfg(test)]
mod tests {
    use crate::conf;
    use crate::error::GameError;
    use crate::filesystem::{env, vfs, Arc, Filesystem, RwLock, CONFIG_NAME};
    use std::io::{Read, Write};
    use std::path;

    fn dummy_fs_for_tests() -> Filesystem {
        let mut path = path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        path.push("resources");
        let physfs = vfs::PhysicalFS::new(&path, false);
        let mut ofs = vfs::OverlayFS::new();
        ofs.push_front(Box::new(physfs));
        Filesystem {
            vfs: Arc::new(RwLock::new(ofs)),

            resources_dir: "".into(),
            zip_dir: "".into(),
            user_config_dir: "".into(),
            user_data_dir: "".into(),
        }
    }

    #[test]
    fn headless_test_file_exists() {
        let f = dummy_fs_for_tests();

        let tile_file = path::Path::new("/tile.png");
        assert!(f.exists(tile_file));
        assert!(f.is_file(tile_file));

        let tile_file = path::Path::new("/oglebog.png");
        assert!(!f.exists(tile_file));
        assert!(!f.is_file(tile_file));
        assert!(!f.is_dir(tile_file));
    }

    #[test]
    fn headless_test_read_dir() {
        let f = dummy_fs_for_tests();

        let dir_contents_size = f.read_dir("/").unwrap().len();
        assert!(dir_contents_size > 0);
    }

    #[test]
    fn headless_test_create_delete_file() {
        let fs = dummy_fs_for_tests();
        let test_file = path::Path::new("/testfile.txt");
        let bytes = b"test";

        {
            let mut file = fs.create(test_file).unwrap();
            let _ = file.write(bytes).unwrap();
        }
        {
            let mut buffer = Vec::new();
            let mut file = fs.open(test_file).unwrap();
            let _ = file.read_to_end(&mut buffer).unwrap();
            assert_eq!(bytes, buffer.as_slice());
        }

        fs.delete(test_file).unwrap();
    }

    #[test]
    fn headless_test_file_not_found() {
        let fs = dummy_fs_for_tests();
        {
            let rel_file = "testfile.txt";
            match fs.open(rel_file) {
                Err(GameError::ResourceNotFound(_, _)) => (),
                Err(e) => panic!("Invalid error for opening file with relative path: {e:?}"),
                Ok(f) => panic!("Should have gotten an error but instead got {f:?}!"),
            }
        }

        {
            // This absolute path should work on Windows too since we
            // completely remove filesystem roots.
            match fs.open("/ooglebooglebarg.txt") {
                Err(GameError::ResourceNotFound(_, _)) => (),
                Err(e) => panic!("Invalid error for opening nonexistent file: {e}"),
                Ok(f) => panic!("Should have gotten an error but instead got {f:?}"),
            }
        }
    }

    #[test]
    fn headless_test_write_config() {
        let f = dummy_fs_for_tests();
        let conf = conf::Conf::new();
        // The config file should end up in
        // the resources directory with this
        match f.write_config(&conf) {
            Ok(_) => (),
            Err(e) => panic!("{e:?}"),
        }
        // Remove the config file!
        f.delete(CONFIG_NAME).unwrap();
    }
}