Extract Elixir extension (#10948)

This PR extracts Elixir support into an extension and removes the
built-in Elixir support from Zed.

As part of this, [Lexical](https://github.com/lexical-lsp/lexical) has
been added as an available language server for Elixir.

Since the Elixir extension provides three different language servers,
you'll need to use the `language_servers` setting to select the one you
want to use:

#### Elixir LS

```json
{
  "languages": {
    "Elixir": {
      "language_servers": [ "elixir-ls", "!next-ls", "!lexical", "..."]
    }
  }
}
```

#### Next LS

```json
{
  "languages": {
    "Elixir": {
      "language_servers": [ "next-ls", "!elixir-ls", "!lexical", "..."]
    }
  }
}
```

#### Lexical

```json
{
  "languages": {
    "Elixir": {
      "language_servers": [ "lexical", "!elixir-ls", "!next-ls", "..."]
    }
  }
}
```

These can either go in your user settings or your project settings.

Release Notes:

- Removed built-in support for Elixir, in favor of making it available
as an extension.

extensions/elixir/src/elixir.rs

@@ -0,0 +1,107 @@
+mod language_servers;
+
+use zed::lsp::{Completion, Symbol};
+use zed::{serde_json, CodeLabel, LanguageServerId};
+use zed_extension_api::{self as zed, Result};
+
+use crate::language_servers::{ElixirLs, Lexical, NextLs};
+
+struct ElixirExtension {
+    elixir_ls: Option<ElixirLs>,
+    next_ls: Option<NextLs>,
+    lexical: Option<Lexical>,
+}
+
+impl zed::Extension for ElixirExtension {
+    fn new() -> Self {
+        Self {
+            elixir_ls: None,
+            next_ls: None,
+            lexical: None,
+        }
+    }
+
+    fn language_server_command(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<zed::Command> {
+        match language_server_id.as_ref() {
+            ElixirLs::LANGUAGE_SERVER_ID => {
+                let elixir_ls = self.elixir_ls.get_or_insert_with(|| ElixirLs::new());
+
+                Ok(zed::Command {
+                    command: elixir_ls.language_server_binary_path(language_server_id, worktree)?,
+                    args: vec![],
+                    env: Default::default(),
+                })
+            }
+            NextLs::LANGUAGE_SERVER_ID => {
+                let next_ls = self.next_ls.get_or_insert_with(|| NextLs::new());
+
+                Ok(zed::Command {
+                    command: next_ls.language_server_binary_path(language_server_id, worktree)?,
+                    args: vec!["--stdio".to_string()],
+                    env: Default::default(),
+                })
+            }
+            Lexical::LANGUAGE_SERVER_ID => {
+                let lexical = self.lexical.get_or_insert_with(|| Lexical::new());
+
+                Ok(zed::Command {
+                    command: lexical.language_server_binary_path(language_server_id, worktree)?,
+                    args: vec![],
+                    env: Default::default(),
+                })
+            }
+            language_server_id => Err(format!("unknown language server: {language_server_id}")),
+        }
+    }
+
+    fn label_for_completion(
+        &self,
+        language_server_id: &LanguageServerId,
+        completion: Completion,
+    ) -> Option<CodeLabel> {
+        match language_server_id.as_ref() {
+            ElixirLs::LANGUAGE_SERVER_ID => {
+                self.elixir_ls.as_ref()?.label_for_completion(completion)
+            }
+            NextLs::LANGUAGE_SERVER_ID => self.next_ls.as_ref()?.label_for_completion(completion),
+            Lexical::LANGUAGE_SERVER_ID => self.lexical.as_ref()?.label_for_completion(completion),
+            _ => None,
+        }
+    }
+
+    fn label_for_symbol(
+        &self,
+        language_server_id: &LanguageServerId,
+        symbol: Symbol,
+    ) -> Option<CodeLabel> {
+        match language_server_id.as_ref() {
+            ElixirLs::LANGUAGE_SERVER_ID => self.elixir_ls.as_ref()?.label_for_symbol(symbol),
+            NextLs::LANGUAGE_SERVER_ID => self.next_ls.as_ref()?.label_for_symbol(symbol),
+            Lexical::LANGUAGE_SERVER_ID => self.lexical.as_ref()?.label_for_symbol(symbol),
+            _ => None,
+        }
+    }
+
+    fn language_server_initialization_options(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        _worktree: &zed::Worktree,
+    ) -> Result<Option<serde_json::Value>> {
+        match language_server_id.as_ref() {
+            NextLs::LANGUAGE_SERVER_ID => Ok(Some(serde_json::json!({
+                "experimental": {
+                    "completions": {
+                        "enable": true
+                    }
+                }
+            }))),
+            _ => Ok(None),
+        }
+    }
+}
+
+zed::register_extension!(ElixirExtension);

extensions/elixir/src/language_servers.rs

@@ -0,0 +1,7 @@
+mod elixir_ls;
+mod lexical;
+mod next_ls;
+
+pub use elixir_ls::*;
+pub use lexical::*;
+pub use next_ls::*;

extensions/elixir/src/language_servers/elixir_ls.rs

@@ -0,0 +1,165 @@
+use std::fs;
+
+use zed::lsp::{Completion, CompletionKind, Symbol, SymbolKind};
+use zed::{CodeLabel, CodeLabelSpan, LanguageServerId};
+use zed_extension_api::{self as zed, Result};
+
+pub struct ElixirLs {
+    cached_binary_path: Option<String>,
+}
+
+impl ElixirLs {
+    pub const LANGUAGE_SERVER_ID: &'static str = "elixir-ls";
+
+    pub fn new() -> Self {
+        Self {
+            cached_binary_path: None,
+        }
+    }
+
+    pub fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<String> {
+        if let Some(path) = worktree.which("elixir-ls") {
+            return Ok(path);
+        }
+
+        if let Some(path) = &self.cached_binary_path {
+            if fs::metadata(path).map_or(false, |stat| stat.is_file()) {
+                return Ok(path.clone());
+            }
+        }
+
+        zed::set_language_server_installation_status(
+            &language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let release = zed::latest_github_release(
+            "elixir-lsp/elixir-ls",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        )?;
+
+        let asset_name = format!("elixir-ls-{version}.zip", version = release.version,);
+
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| format!("no asset found matching {:?}", asset_name))?;
+
+        let (platform, _arch) = zed::current_platform();
+        let version_dir = format!("elixir-ls-{}", release.version);
+        let binary_path = format!(
+            "{version_dir}/language_server.{extension}",
+            extension = match platform {
+                zed::Os::Mac | zed::Os::Linux => "sh",
+                zed::Os::Windows => "bat",
+            }
+        );
+
+        if !fs::metadata(&binary_path).map_or(false, |stat| stat.is_file()) {
+            zed::set_language_server_installation_status(
+                &language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+
+            zed::download_file(
+                &asset.download_url,
+                &version_dir,
+                zed::DownloadedFileType::Zip,
+            )
+            .map_err(|e| format!("failed to download file: {e}"))?;
+
+            let entries =
+                fs::read_dir(".").map_err(|e| format!("failed to list working directory {e}"))?;
+            for entry in entries {
+                let entry = entry.map_err(|e| format!("failed to load directory entry {e}"))?;
+                if entry.file_name().to_str() != Some(&version_dir) {
+                    fs::remove_dir_all(&entry.path()).ok();
+                }
+            }
+        }
+
+        self.cached_binary_path = Some(binary_path.clone());
+        Ok(binary_path)
+    }
+
+    pub fn label_for_completion(&self, completion: Completion) -> Option<CodeLabel> {
+        match completion.kind? {
+            CompletionKind::Module
+            | CompletionKind::Class
+            | CompletionKind::Interface
+            | CompletionKind::Struct => {
+                let name = completion.label;
+                let defmodule = "defmodule ";
+                let code = format!("{defmodule}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        defmodule.len()..defmodule.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Function | CompletionKind::Constant => {
+                let name = completion.label;
+                let def = "def ";
+                let code = format!("{def}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(def.len()..def.len() + name.len())],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Operator => {
+                let name = completion.label;
+                let def_a = "def a ";
+                let code = format!("{def_a}{name} b");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        def_a.len()..def_a.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            _ => None,
+        }
+    }
+
+    pub fn label_for_symbol(&self, symbol: Symbol) -> Option<CodeLabel> {
+        let name = &symbol.name;
+
+        let (code, filter_range, display_range) = match symbol.kind {
+            SymbolKind::Module | SymbolKind::Class | SymbolKind::Interface | SymbolKind::Struct => {
+                let defmodule = "defmodule ";
+                let code = format!("{defmodule}{name}");
+                let filter_range = 0..name.len();
+                let display_range = defmodule.len()..defmodule.len() + name.len();
+                (code, filter_range, display_range)
+            }
+            SymbolKind::Function | SymbolKind::Constant => {
+                let def = "def ";
+                let code = format!("{def}{name}");
+                let filter_range = 0..name.len();
+                let display_range = def.len()..def.len() + name.len();
+                (code, filter_range, display_range)
+            }
+            _ => return None,
+        };
+
+        Some(CodeLabel {
+            spans: vec![CodeLabelSpan::code_range(display_range)],
+            filter_range: filter_range.into(),
+            code,
+        })
+    }
+}

extensions/elixir/src/language_servers/lexical.rs

@@ -0,0 +1,130 @@
+use std::fs;
+
+use zed::lsp::{Completion, CompletionKind, Symbol};
+use zed::{CodeLabel, CodeLabelSpan, LanguageServerId};
+use zed_extension_api::{self as zed, Result};
+
+pub struct Lexical {
+    cached_binary_path: Option<String>,
+}
+
+impl Lexical {
+    pub const LANGUAGE_SERVER_ID: &'static str = "lexical";
+
+    pub fn new() -> Self {
+        Self {
+            cached_binary_path: None,
+        }
+    }
+
+    pub fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        _worktree: &zed::Worktree,
+    ) -> Result<String> {
+        if let Some(path) = &self.cached_binary_path {
+            if fs::metadata(path).map_or(false, |stat| stat.is_file()) {
+                return Ok(path.clone());
+            }
+        }
+
+        zed::set_language_server_installation_status(
+            &language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let release = zed::latest_github_release(
+            "lexical-lsp/lexical",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        )?;
+
+        let asset_name = format!("lexical-{version}.zip", version = release.version);
+
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| format!("no asset found matching {:?}", asset_name))?;
+
+        let version_dir = format!("lexical-{}", release.version);
+        let binary_path = format!("{version_dir}/lexical/bin/start_lexical.sh");
+
+        if !fs::metadata(&binary_path).map_or(false, |stat| stat.is_file()) {
+            zed::set_language_server_installation_status(
+                &language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+
+            zed::download_file(
+                &asset.download_url,
+                &version_dir,
+                zed::DownloadedFileType::Zip,
+            )
+            .map_err(|e| format!("failed to download file: {e}"))?;
+
+            let entries =
+                fs::read_dir(".").map_err(|e| format!("failed to list working directory {e}"))?;
+            for entry in entries {
+                let entry = entry.map_err(|e| format!("failed to load directory entry {e}"))?;
+                if entry.file_name().to_str() != Some(&version_dir) {
+                    fs::remove_dir_all(&entry.path()).ok();
+                }
+            }
+        }
+
+        self.cached_binary_path = Some(binary_path.clone());
+        Ok(binary_path)
+    }
+
+    pub fn label_for_completion(&self, completion: Completion) -> Option<CodeLabel> {
+        match completion.kind? {
+            CompletionKind::Module
+            | CompletionKind::Class
+            | CompletionKind::Interface
+            | CompletionKind::Struct => {
+                let name = completion.label;
+                let defmodule = "defmodule ";
+                let code = format!("{defmodule}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        defmodule.len()..defmodule.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Function | CompletionKind::Constant => {
+                let name = completion.label;
+                let def = "def ";
+                let code = format!("{def}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(def.len()..def.len() + name.len())],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Operator => {
+                let name = completion.label;
+                let def_a = "def a ";
+                let code = format!("{def_a}{name} b");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        def_a.len()..def_a.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            _ => None,
+        }
+    }
+
+    pub fn label_for_symbol(&self, _symbol: Symbol) -> Option<CodeLabel> {
+        None
+    }
+}

extensions/elixir/src/language_servers/next_ls.rs

@@ -0,0 +1,176 @@
+use std::fs;
+
+use zed::lsp::{Completion, CompletionKind, Symbol, SymbolKind};
+use zed::{CodeLabel, CodeLabelSpan, LanguageServerId};
+use zed_extension_api::{self as zed, Result};
+
+pub struct NextLs {
+    cached_binary_path: Option<String>,
+}
+
+impl NextLs {
+    pub const LANGUAGE_SERVER_ID: &'static str = "next-ls";
+
+    pub fn new() -> Self {
+        Self {
+            cached_binary_path: None,
+        }
+    }
+
+    pub fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        _worktree: &zed::Worktree,
+    ) -> Result<String> {
+        if let Some(path) = &self.cached_binary_path {
+            if fs::metadata(path).map_or(false, |stat| stat.is_file()) {
+                return Ok(path.clone());
+            }
+        }
+
+        zed::set_language_server_installation_status(
+            &language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let release = zed::latest_github_release(
+            "elixir-tools/next-ls",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        )?;
+
+        let (platform, arch) = zed::current_platform();
+        let asset_name = format!(
+            "next_ls_{os}_{arch}{extension}",
+            os = match platform {
+                zed::Os::Mac => "darwin",
+                zed::Os::Linux => "linux",
+                zed::Os::Windows => "windows",
+            },
+            arch = match arch {
+                zed::Architecture::Aarch64 => "arm64",
+                zed::Architecture::X8664 => "amd64",
+                zed::Architecture::X86 =>
+                    return Err(format!("unsupported architecture: {arch:?}")),
+            },
+            extension = match platform {
+                zed::Os::Mac | zed::Os::Linux => "",
+                zed::Os::Windows => ".exe",
+            }
+        );
+
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| format!("no asset found matching {:?}", asset_name))?;
+
+        let version_dir = format!("next-ls-{}", release.version);
+        fs::create_dir_all(&version_dir).map_err(|e| format!("failed to create directory: {e}"))?;
+
+        let binary_path = format!("{version_dir}/next-ls");
+
+        if !fs::metadata(&binary_path).map_or(false, |stat| stat.is_file()) {
+            zed::set_language_server_installation_status(
+                &language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+
+            zed::download_file(
+                &asset.download_url,
+                &binary_path,
+                zed::DownloadedFileType::Uncompressed,
+            )
+            .map_err(|e| format!("failed to download file: {e}"))?;
+
+            zed::make_file_executable(&binary_path)?;
+
+            let entries =
+                fs::read_dir(".").map_err(|e| format!("failed to list working directory {e}"))?;
+            for entry in entries {
+                let entry = entry.map_err(|e| format!("failed to load directory entry {e}"))?;
+                if entry.file_name().to_str() != Some(&version_dir) {
+                    fs::remove_dir_all(&entry.path()).ok();
+                }
+            }
+        }
+
+        self.cached_binary_path = Some(binary_path.clone());
+        Ok(binary_path)
+    }
+
+    pub fn label_for_completion(&self, completion: Completion) -> Option<CodeLabel> {
+        match completion.kind? {
+            CompletionKind::Module
+            | CompletionKind::Class
+            | CompletionKind::Interface
+            | CompletionKind::Struct => {
+                let name = completion.label;
+                let defmodule = "defmodule ";
+                let code = format!("{defmodule}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        defmodule.len()..defmodule.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Function | CompletionKind::Constant => {
+                let name = completion.label;
+                let def = "def ";
+                let code = format!("{def}{name}");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(def.len()..def.len() + name.len())],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            CompletionKind::Operator => {
+                let name = completion.label;
+                let def_a = "def a ";
+                let code = format!("{def_a}{name} b");
+
+                Some(CodeLabel {
+                    code,
+                    spans: vec![CodeLabelSpan::code_range(
+                        def_a.len()..def_a.len() + name.len(),
+                    )],
+                    filter_range: (0..name.len()).into(),
+                })
+            }
+            _ => None,
+        }
+    }
+
+    pub fn label_for_symbol(&self, symbol: Symbol) -> Option<CodeLabel> {
+        let name = &symbol.name;
+
+        let (code, filter_range, display_range) = match symbol.kind {
+            SymbolKind::Module | SymbolKind::Class | SymbolKind::Interface | SymbolKind::Struct => {
+                let defmodule = "defmodule ";
+                let code = format!("{defmodule}{name}");
+                let filter_range = 0..name.len();
+                let display_range = defmodule.len()..defmodule.len() + name.len();
+                (code, filter_range, display_range)
+            }
+            SymbolKind::Function | SymbolKind::Constant => {
+                let def = "def ";
+                let code = format!("{def}{name}");
+                let filter_range = 0..name.len();
+                let display_range = def.len()..def.len() + name.len();
+                (code, filter_range, display_range)
+            }
+            _ => return None,
+        };
+
+        Some(CodeLabel {
+            spans: vec![CodeLabelSpan::code_range(display_range)],
+            filter_range: filter_range.into(),
+            code,
+        })
+    }
+}