refactor methods into submodule, impl simple msg loop

Author: ethangreen-dev

src/server/lock.rs

@@ -0,0 +1,31 @@
+use std::fs::{self, File};
+use std::path::{Path, PathBuf};
+
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    #[error("The lock at {0:?} is already acquired by a process with PID {1}.")]
+    InUse(PathBuf, u32),
+}
+
+/// Only one server process can "own" a project at a single time.
+/// We enforce this exclusive access through the creation and deletion of this lockfile.
+const LOCKFILE: &'static str = ".server-lock";
+
+pub struct ProjectLock<'a> {
+    file: File,
+    path: &'a Path,
+}
+
+impl<'a> ProjectLock<'_> {
+    /// Attempt to acquire a lock on the provided directory.
+    pub fn lock(project_path: &'a Path) -> Result<Self, Error> {
+        todo!()
+    }
+}
+
+impl Drop for ProjectLock<'_> {
+    fn drop(&mut self) {
+        // The file handle is dropped before this, so we can safely delete it.
+        fs::remove_file(self.path);
+    }
+}

src/server/method.rs

@@ -0,0 +1,43 @@
+pub mod package;
+pub mod project;
+
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize};
+
+use self::package::PackageMethod;
+use self::project::ProjectMethod;
+use super::Error;
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub enum Method {
+    Exit,
+    Project(ProjectMethod),
+    Package(PackageMethod),
+}
+
+/// Method namespace registration.
+impl Method {
+    pub fn from_value(method: &str, value: serde_json::Value) -> Result<Self, Error> {
+        let mut split = method.split('/');
+        let (namespace, name) = (
+            split
+                .next()
+                .ok_or_else(|| Error::InvalidMethod(method.into()))?,
+            split
+                .next()
+                .ok_or_else(|| Error::InvalidMethod(method.into()))?,
+        );
+
+        // Route namespaces to the appropriate enum variants for construction.
+        Ok(match namespace {
+            "exit" => Self::Exit,
+            "project" => Self::Project(ProjectMethod::from_value(name, value)?),
+            "package" => Self::Package(PackageMethod::from_value(name, value)?),
+            x => Err(Error::InvalidMethod(x.into()))?,
+        })
+    }
+}
+
+pub fn parse_value<T: DeserializeOwned>(value: serde_json::Value) -> Result<T, serde_json::Error> {
+    serde_json::from_value(value)
+}

src/server/method/mod.rs

@@ -0,0 +1,21 @@
+use serde::{Deserialize, Serialize};
+
+use super::Error;
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub enum PackageMethod {
+    /// Get metadata about this package.
+    GetMetadata,
+    /// Determine if the package exists within the cache.
+    IsCached,
+}
+
+impl PackageMethod {
+    pub fn from_value(method: &str, value: serde_json::Value) -> Result<Self, Error> {
+        Ok(match method {
+            "get_metadata" => Self::GetMetadata,
+            "is_cached" => Self::IsCached,
+            x => Err(Error::InvalidMethod(x.into()))?,
+        })
+    }
+}

src/server/method/package.rs

@@ -0,0 +1,55 @@
+use std::path::PathBuf;
+
+use serde::{Deserialize, Serialize};
+
+use crate::ts::package_reference::PackageReference;
+
+use super::Error;
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub enum ProjectMethod {
+    /// Set the project directory context. This locks the project, if it exists.
+    SetContext(SetContext),
+    /// Release the project directory context. This unlocks the project, if a lock exists.
+    ReleaseContext,
+    /// Get project metadata.
+    GetMetadata,
+    /// Add one or more packages to the project.
+    AddPackages(AddPackages),
+    /// Remove one or more packages from the project.
+    RemovePackages(RemovePackages),
+    /// Get a list of currently installed packages.
+    GetPackages,
+    /// Determine if the current context is a valid project.
+    IsValid,
+}
+
+impl ProjectMethod {
+    pub fn from_value(method: &str, value: serde_json::Value) -> Result<Self, Error> {
+        Ok(match method {
+            "set_context" => Self::SetContext(super::parse_value(value)?),
+            "release_context" => Self::ReleaseContext,
+            "get_metadata" => Self::GetMetadata,
+            "add_packages" => Self::AddPackages(super::parse_value(value)?),
+            "remove_packages" => Self::RemovePackages(super::parse_value(value)?),
+            "get_packages" => Self::GetPackages,
+            "is_valid" => Self::IsValid,
+            x => Err(Error::InvalidMethod(x.into()))?,
+        })
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub struct SetContext {
+    path: PathBuf,
+}
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub struct AddPackages {
+    packages: Vec<PackageReference>,
+}
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
+pub struct RemovePackages {
+    packages: Vec<PackageReference>,
+}

src/server/method/project.rs

@@ -1,8 +1,90 @@
+use std::io::Write;
+use std::sync::mpsc::{self, Receiver, Sender};
+use std::sync::RwLock;
+use std::{io, thread};
+
+use self::proto::{Message, Request, Response};
+
 mod method;
 mod proto;
+mod route;
+
+trait ToJson {
+    fn to_json(&self) -> Result<String, serde_json::Error>;
+}
+
+/// This error type exists to wrap library errors into a single easy-to-use package.
+#[derive(thiserror::Error, Debug)]
+#[repr(isize)]
+pub enum Error {
+    /// A partial implementation of the error variants described by the JRPC spec.
+    #[error("Failed to serialize JSON: {0:?}")]
+    InvalidJson(#[from] serde_json::Error) = -32700,
+
+    #[error("The method {0} is not valid.")]
+    InvalidMethod(String) = -32601,
+
+    #[error("Recieved invalid params for method {0}: {1}")]
+    InvalidParams(String, String) = -32602,
+
+    /// Wrapper error types and codes.
+    #[error("${0:?}")]
+    ProjectError(String) = 1000,
+
+    #[error("{0:?}")]
+    PackageError(String) = 2000,
+}
+
+impl Error {
+    pub fn discriminant(&self) -> isize {
+        // SAFETY: `Self` is `repr(isize)` with layout `repr(C)`, with each variant having an isize
+        // as its first field, so we can access this value without a pointer offset.
+        unsafe { *<*const _>::from(self).cast::<isize>() }
+    }
+}
+
+impl ToJson for Result<Response, Error> {
+    fn to_json(&self) -> Result<String, serde_json::Error> {
+        todo!()
+    }
+}
 
 /// The daemon's entrypoint. This is a psuedo event loop which does the following in step:
 /// 1. Read JSON-RPC input(s) from stdin.
 /// 2. Route each input.
 /// 3. Serialize the output and write to stdout.
-pub async fn start() {}
+async fn start() {
+    let stdin = io::stdin();
+    let mut line = String::new();
+    let (tx, rx) = mpsc::channel::<Result<Response, Error>>();
+
+    let cancel = RwLock::new(false);
+
+    // Responses are published through the tx send channel.
+    thread::spawn(move || respond_msg(rx, cancel));
+
+    loop {
+        // Block the main thread until we have an input line available to be read.
+        // This is ok because, in theory, tasks will be processed on background threads.
+        if let Err(e) = stdin.read_line(&mut line) {
+            panic!("")
+        }
+        let res = route(&line, tx.clone()).await;
+        res.to_json().unwrap();
+    }
+}
+
+fn respond_msg(rx: Receiver<Result<Response, Error>>, cancel: RwLock<bool>) {
+    let mut stdout = io::stdout();
+    while let Ok(res) = rx.recv() {
+        let msg = res.map(|x| serde_json::to_string(&x).unwrap());
+        stdout.write_all(msg.unwrap().as_bytes());
+        stdout.write_all("\n".as_bytes());
+    }
+}
+
+/// Route and execute the request, returning the result.
+async fn route(line: &str, tx: Sender<Result<Response, Error>>) -> Result<Response, Error> {
+    let req = Message::from_json(line);
+    todo!()
+}