Start on Elixir LSP integration

crates/zed/src/languages.rs

@@ -5,6 +5,7 @@ use rust_embed::RustEmbed;
 use std::{borrow::Cow, str, sync::Arc};
 
 mod c;
+mod elixir;
 mod go;
 mod installation;
 mod json;
@@ -45,7 +46,11 @@ pub async fn init(languages: Arc<LanguageRegistry>, _executor: Arc<Background>)
             tree_sitter_cpp::language(),
             Some(CachedLspAdapter::new(c::CLspAdapter).await),
         ),
-        ("elixir", tree_sitter_elixir::language(), None),
+        (
+            "elixir",
+            tree_sitter_elixir::language(),
+            Some(CachedLspAdapter::new(elixir::ElixirLspAdapter).await),
+        ),
         (
             "go",
             tree_sitter_go::language(),

crates/zed/src/languages/elixir.rs

@@ -0,0 +1,111 @@
+use super::installation::{latest_github_release, GitHubLspBinaryVersion};
+use anyhow::{anyhow, Context, Result};
+use async_trait::async_trait;
+use client::http::HttpClient;
+use futures::StreamExt;
+pub use language::*;
+use smol::fs::{self, File};
+use std::{any::Any, path::PathBuf, sync::Arc};
+use util::ResultExt;
+
+pub struct ElixirLspAdapter;
+
+#[async_trait]
+impl LspAdapter for ElixirLspAdapter {
+    async fn name(&self) -> LanguageServerName {
+        LanguageServerName("elixir-ls".into())
+    }
+
+    async fn fetch_latest_server_version(
+        &self,
+        http: Arc<dyn HttpClient>,
+    ) -> Result<Box<dyn 'static + Send + Any>> {
+        let release = latest_github_release("elixir-lsp/elixir-ls", http).await?;
+        let asset_name = "elixir-ls.zip";
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| anyhow!("no asset found matching {:?}", asset_name))?;
+        let version = GitHubLspBinaryVersion {
+            name: release.name,
+            url: asset.browser_download_url.clone(),
+        };
+        Ok(Box::new(version) as Box<_>)
+    }
+
+    async fn fetch_server_binary(
+        &self,
+        version: Box<dyn 'static + Send + Any>,
+        http: Arc<dyn HttpClient>,
+        container_dir: PathBuf,
+    ) -> Result<PathBuf> {
+        let version = version.downcast::<GitHubLspBinaryVersion>().unwrap();
+        let zip_path = container_dir.join(format!("elixir-ls_{}.zip", version.name));
+        let version_dir = container_dir.join(format!("elixir-ls_{}", version.name));
+        let binary_path = version_dir.join("language_server.sh");
+
+        if fs::metadata(&binary_path).await.is_err() {
+            let mut response = http
+                .get(&version.url, Default::default(), true)
+                .await
+                .context("error downloading release")?;
+            let mut file = File::create(&zip_path)
+                .await
+                .with_context(|| format!("failed to create file {}", zip_path.display()))?;
+            if !response.status().is_success() {
+                Err(anyhow!(
+                    "download failed with status {}",
+                    response.status().to_string()
+                ))?;
+            }
+            futures::io::copy(response.body_mut(), &mut file).await?;
+
+            fs::create_dir_all(&version_dir)
+                .await
+                .with_context(|| format!("failed to create directory {}", version_dir.display()))?;
+            let unzip_status = smol::process::Command::new("unzip")
+                .arg(&zip_path)
+                .arg("-d")
+                .arg(&version_dir)
+                .output()
+                .await?
+                .status;
+            if !unzip_status.success() {
+                Err(anyhow!("failed to unzip clangd archive"))?;
+            }
+
+            if let Some(mut entries) = fs::read_dir(&container_dir).await.log_err() {
+                while let Some(entry) = entries.next().await {
+                    if let Some(entry) = entry.log_err() {
+                        let entry_path = entry.path();
+                        if entry_path.as_path() != version_dir {
+                            if let Ok(metadata) = fs::metadata(&entry_path).await {
+                                if metadata.is_file() {
+                                    fs::remove_file(&entry_path).await.log_err();
+                                } else {
+                                    fs::remove_dir_all(&entry_path).await.log_err();
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        Ok(binary_path)
+    }
+
+    async fn cached_server_binary(&self, container_dir: PathBuf) -> Option<PathBuf> {
+        (|| async move {
+            let mut last = None;
+            let mut entries = fs::read_dir(&container_dir).await?;
+            while let Some(entry) = entries.next().await {
+                last = Some(entry?.path());
+            }
+            last.ok_or_else(|| anyhow!("no cached binary"))
+        })()
+        .await
+        .log_err()
+    }
+}