Implement metadata api for fs builtin

CHANGELOG.md

@@ -12,7 +12,23 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Added support for running directories with an `init.luau` or `init.lua` file in them in the CLI
+- Added support for running directories with an `init.luau` or `init.lua` file in them in the CLI.
+- Added `fs.metadata` to get metadata about files and directories.
+
+  Example usage:
+
+  ```lua
+  local fs = require("@lune/fs")
+
+  fs.writeFile("myAwesomeFile.json", "{}")
+
+  local meta = fs.metadata("myAwesomeFile.json")
+
+  print(meta.exists) --> true
+  print(meta.kind) --> "file"
+  print(meta.createdAt) --> 1689848548.0577152 (unix timestamp)
+  print(meta.permissions) --> { readOnly: false }
+  ```
 
 ### Changed
 
@@ -20,10 +36,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
-- Fixed publishing of Lune to crates.io by migrating away from a monorepo
-- Fixed crashes when writing a very deeply nested `Instance` to a file ([#62])
-- Fixed not being able to read & write to WebSocket objects at the same time ([#68])
-- Fixed tab character at the start of a script causing it not to parse correctly ([#72])
+- Fixed publishing of Lune to crates.io by migrating away from a monorepo.
+- Fixed crashes when writing a very deeply nested `Instance` to a file. ([#62])
+- Fixed not being able to read & write to WebSocket objects at the same time. ([#68])
+- Fixed tab character at the start of a script causing it not to parse correctly. ([#72])
 
 [#62]: https://github.com/filiptibell/lune/pull/62
 [#68]: https://github.com/filiptibell/lune/pull/66
@@ -56,7 +72,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- The `lune --setup` command is now much more user-friendly
+- The `lune --setup` command is now much more user-friendly.
 - Update to Luau version `0.581`
 
 ## `0.7.1` - June 17th, 2023

docs/typedefs/FS.luau

@@ -1,3 +1,55 @@
+export type MetadataKind = "file" | "dir" | "symlink"
+
+--[=[
+	@type MetadataPermissions
+	@within FS
+
+	Permissions for the given file or directory.
+
+	This is a dictionary that will contain the following values:
+
+	* `readOnly` - If the target path is read-only or not
+]=]
+export type MetadataPermissions = {
+	readOnly: boolean,
+}
+
+-- FIXME: We lose doc comments here because of the union type
+
+--[=[
+	@type Metadata
+	@within FS
+
+	Metadata for the given file or directory.
+
+	This is a dictionary that will contain the following values:
+
+	* `kind` - If the target path is a `file`, `dir` or `symlink`
+	* `exists` - If the target path exists
+	* `createdAt` - The timestamp at which the file or directory was created
+	* `modifiedAt` - The timestamp at which the file or directory was last modified
+	* `accessedAt` - The timestamp at which the file or directory was last accessed
+	* `permissions` - Current permissions for the file or directory
+
+	Note that timestamps are relative to the unix epoch, and
+	may not be accurate if the system clock is not accurate.
+]=]
+export type Metadata = {
+	kind: MetadataKind,
+	exists: true,
+	createdAt: number,
+	modifiedAt: number,
+	accessedAt: number,
+	permissions: MetadataPermissions,
+} | {
+	kind: nil,
+	exists: false,
+	createdAt: nil,
+	modifiedAt: nil,
+	accessedAt: nil,
+	permissions: nil,
+}
+
 --[=[
 	@type WriteOptions
 	@within FS
@@ -134,6 +186,23 @@ return {
 		@within FS
 		@must_use
 
+		Gets metadata for the given path.
+
+		An error will be thrown in the following situations:
+
+		* The current process lacks permissions to read at `path`.
+		* Some other I/O error occurred.
+
+		@param path The path to get metadata for
+		@return Metadata for the path
+	]=]
+	metadata = function(path: string): Metadata
+		return nil :: any
+	end,
+	--[=[
+		@within FS
+		@must_use
+
 		Checks if a given path is a file.
 
 		An error will be thrown in the following situations:

src/lune/builtins/fs.rs

@@ -1,9 +1,13 @@
+use std::io::ErrorKind as IoErrorKind;
 use std::path::{PathBuf, MAIN_SEPARATOR};
 
 use mlua::prelude::*;
 use tokio::fs;
 
-use crate::lune::lua::{fs::FsWriteOptions, table::TableBuilder};
+use crate::lune::lua::{
+    fs::{FsMetadata, FsWriteOptions},
+    table::TableBuilder,
+};
 
 pub fn create(lua: &'static Lua) -> LuaResult<LuaTable> {
     TableBuilder::new(lua)?
@@ -13,6 +17,7 @@ pub fn create(lua: &'static Lua) -> LuaResult<LuaTable> {
         .with_async_function("writeDir", fs_write_dir)?
         .with_async_function("removeFile", fs_remove_file)?
         .with_async_function("removeDir", fs_remove_dir)?
+        .with_async_function("metadata", fs_metadata)?
         .with_async_function("isFile", fs_is_file)?
         .with_async_function("isDir", fs_is_dir)?
         .with_async_function("move", fs_move)?
@@ -74,27 +79,27 @@ async fn fs_remove_dir(_: &'static Lua, path: String) -> LuaResult<()> {
     fs::remove_dir_all(&path).await.map_err(LuaError::external)
 }
 
+async fn fs_metadata(_: &'static Lua, path: String) -> LuaResult<FsMetadata> {
+    match fs::metadata(path).await {
+        Err(e) if e.kind() == IoErrorKind::NotFound => Ok(FsMetadata::not_found()),
+        Ok(meta) => Ok(FsMetadata::from(meta)),
+        Err(e) => Err(e.into()),
+    }
+}
+
 async fn fs_is_file(_: &'static Lua, path: String) -> LuaResult<bool> {
-    let path = PathBuf::from(path);
-    if path.exists() {
-        Ok(fs::metadata(path)
-            .await
-            .map_err(LuaError::external)?
-            .is_file())
-    } else {
-        Ok(false)
+    match fs::metadata(path).await {
+        Err(e) if e.kind() == IoErrorKind::NotFound => Ok(false),
+        Ok(meta) => Ok(meta.is_file()),
+        Err(e) => Err(e.into()),
     }
 }
 
 async fn fs_is_dir(_: &'static Lua, path: String) -> LuaResult<bool> {
-    let path = PathBuf::from(path);
-    if path.exists() {
-        Ok(fs::metadata(path)
-            .await
-            .map_err(LuaError::external)?
-            .is_dir())
-    } else {
-        Ok(false)
+    match fs::metadata(path).await {
+        Err(e) if e.kind() == IoErrorKind::NotFound => Ok(false),
+        Ok(meta) => Ok(meta.is_dir()),
+        Err(e) => Err(e.into()),
     }
 }
 

src/lune/lua/fs/metadata.rs

@@ -0,0 +1,153 @@
+use std::{
+    fmt,
+    fs::{FileType as StdFileType, Metadata as StdMetadata, Permissions as StdPermissions},
+    io::Result as IoResult,
+    str::FromStr,
+    time::SystemTime,
+};
+
+use mlua::prelude::*;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FsMetadataKind {
+    None,
+    File,
+    Dir,
+    Symlink,
+}
+
+impl fmt::Display for FsMetadataKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                Self::None => "none",
+                Self::File => "file",
+                Self::Dir => "dir",
+                Self::Symlink => "symlink",
+            }
+        )
+    }
+}
+
+impl FromStr for FsMetadataKind {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.trim().to_ascii_lowercase().as_ref() {
+            "none" => Ok(Self::None),
+            "file" => Ok(Self::File),
+            "dir" => Ok(Self::Dir),
+            "symlink" => Ok(Self::Symlink),
+            _ => Err("Invalid metadata kind"),
+        }
+    }
+}
+
+impl From<StdFileType> for FsMetadataKind {
+    fn from(value: StdFileType) -> Self {
+        if value.is_file() {
+            Self::File
+        } else if value.is_dir() {
+            Self::Dir
+        } else if value.is_symlink() {
+            Self::Symlink
+        } else {
+            panic!("Encountered unknown filesystem filetype")
+        }
+    }
+}
+
+impl<'lua> IntoLua<'lua> for FsMetadataKind {
+    fn into_lua(self, lua: &'lua Lua) -> LuaResult<LuaValue<'lua>> {
+        if self == Self::None {
+            Ok(LuaValue::Nil)
+        } else {
+            self.to_string().into_lua(lua)
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct FsPermissions {
+    pub(crate) read_only: bool,
+}
+
+impl From<StdPermissions> for FsPermissions {
+    fn from(value: StdPermissions) -> Self {
+        Self {
+            read_only: value.readonly(),
+        }
+    }
+}
+
+impl<'lua> IntoLua<'lua> for FsPermissions {
+    fn into_lua(self, lua: &'lua Lua) -> LuaResult<LuaValue<'lua>> {
+        let tab = lua.create_table_with_capacity(0, 1)?;
+        tab.set("readOnly", self.read_only)?;
+        tab.set_readonly(true);
+        Ok(LuaValue::Table(tab))
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct FsMetadata {
+    pub(crate) kind: FsMetadataKind,
+    pub(crate) exists: bool,
+    pub(crate) created_at: Option<f64>,
+    pub(crate) modified_at: Option<f64>,
+    pub(crate) accessed_at: Option<f64>,
+    pub(crate) permissions: Option<FsPermissions>,
+}
+
+impl FsMetadata {
+    pub fn not_found() -> Self {
+        Self {
+            kind: FsMetadataKind::None,
+            exists: false,
+            created_at: None,
+            modified_at: None,
+            accessed_at: None,
+            permissions: None,
+        }
+    }
+}
+
+impl<'lua> IntoLua<'lua> for FsMetadata {
+    fn into_lua(self, lua: &'lua Lua) -> LuaResult<LuaValue<'lua>> {
+        let tab = lua.create_table_with_capacity(0, 5)?;
+        tab.set("kind", self.kind)?;
+        tab.set("exists", self.exists)?;
+        tab.set("createdAt", self.created_at)?;
+        tab.set("modifiedAt", self.modified_at)?;
+        tab.set("accessedAt", self.accessed_at)?;
+        tab.set("permissions", self.permissions)?;
+        tab.set_readonly(true);
+        Ok(LuaValue::Table(tab))
+    }
+}
+
+impl From<StdMetadata> for FsMetadata {
+    fn from(value: StdMetadata) -> Self {
+        Self {
+            kind: value.file_type().into(),
+            exists: true,
+            // FUTURE: Turn these into DateTime structs instead when that's implemented
+            created_at: system_time_to_timestamp(value.created()),
+            modified_at: system_time_to_timestamp(value.modified()),
+            accessed_at: system_time_to_timestamp(value.accessed()),
+            permissions: Some(FsPermissions::from(value.permissions())),
+        }
+    }
+}
+
+fn system_time_to_timestamp(res: IoResult<SystemTime>) -> Option<f64> {
+    match res {
+        Ok(t) => match t.duration_since(SystemTime::UNIX_EPOCH) {
+            Ok(d) => Some(d.as_secs_f64()),
+            Err(_) => None,
+        },
+        Err(_) => None,
+    }
+}

src/lune/lua/fs/mod.rs

@@ -1,3 +1,5 @@
+mod metadata;
 mod options;
 
+pub use metadata::FsMetadata;
 pub use options::FsWriteOptions;

src/tests.rs

@@ -40,6 +40,7 @@ macro_rules! create_tests {
 create_tests! {
     fs_files: "fs/files",
     fs_dirs: "fs/dirs",
+    fs_metadata: "fs/metadata",
     fs_move: "fs/move",
 
     net_request_codes: "net/request/codes",

tests/fs/metadata.luau

@@ -0,0 +1,70 @@
+local TEMP_DIR_PATH = "bin/"
+local TEMP_FILE_PATH = TEMP_DIR_PATH .. "metadata_test"
+
+local fs = require("@lune/fs")
+local task = require("@lune/task")
+
+-- Generate test data & make sure our bin dir exists
+
+local binary = ""
+for _ = 1, 1024 do
+	binary ..= string.char(math.random(1, 127))
+end
+
+fs.writeDir(TEMP_DIR_PATH)
+if fs.isFile(TEMP_FILE_PATH) then
+	fs.removeFile(TEMP_FILE_PATH)
+end
+
+--[[
+	1. File should initially not exist
+	2. Write the file
+	3. File should now exist
+]]
+
+assert(not fs.metadata(TEMP_FILE_PATH).exists, "File metadata not exists failed")
+fs.writeFile(TEMP_FILE_PATH, binary)
+assert(fs.metadata(TEMP_FILE_PATH).exists, "File metadata exists failed")
+
+--[[
+	1. Kind should be `dir` for our temp directory
+	2. Kind should be `file` for our temp file
+]]
+
+local metaDir = fs.metadata(TEMP_DIR_PATH)
+local metaFile = fs.metadata(TEMP_FILE_PATH)
+assert(metaDir.kind == "dir", "Dir metadata kind was invalid")
+assert(metaFile.kind == "file", "File metadata kind was invalid")
+
+--[[
+	1. Capture initial metadata
+	2. Wait for a bit so that timestamps can change
+	3. Write the file, with an extra newline
+	4. Metadata changed timestamp should be different
+	5. Metadata created timestamp should be the same different
+]]
+
+local metaBefore = fs.metadata(TEMP_FILE_PATH)
+task.wait()
+fs.writeFile(TEMP_FILE_PATH, binary .. "\n")
+local metaAfter = fs.metadata(TEMP_FILE_PATH)
+
+assert(
+	metaAfter.modifiedAt ~= metaBefore.modifiedAt,
+	"File metadata change timestamp did not change"
+)
+assert(
+	metaAfter.createdAt == metaBefore.createdAt,
+	"File metadata creation timestamp changed from modification"
+)
+
+--[[
+	1. Permissions should exist
+	2. Our newly created file should not be readonly
+]]
+assert(metaAfter.permissions ~= nil, "File metadata permissions are missing")
+assert(not metaAfter.permissions.readOnly, "File metadata permissions are readonly")
+
+-- Finally, clean up after us for any subsequent tests
+
+fs.removeFile(TEMP_FILE_PATH)