Add language-agnostic snippets (#13253)

Note that right now we can't attach a language server to arbitrary
buffer, which is why I've listed a bunch of languages verbatim.
See
https://github.com/zed-industries/simple-completion-language-server/tree/main
for docs on how to define your snippets. They should be placed in
~/.config/zed/snippets ; `snippets.(toml|json)` file can be used to
define language-agnostic snippets, and any other name (e.g.
`python.toml`) will apply only to buffers of that particular type.

There's https://github.com/rafamadriz/friendly-snippets you can use as a
repository of snippets, for your convenience.

Fixes https://github.com/zed-industries/zed/issues/4611

Release Notes:
- Added support for snippets via simple-completion-language-server

Cargo.lock

@@ -13584,6 +13584,14 @@ dependencies = [
  "zed_extension_api 0.0.6",
 ]
 
+[[package]]
+name = "zed_snippets"
+version = "0.0.1"
+dependencies = [
+ "serde_json",
+ "zed_extension_api 0.0.6",
+]
+
 [[package]]
 name = "zed_svelte"
 version = "0.0.1"

Cargo.toml

@@ -136,6 +136,7 @@ members = [
     "extensions/prisma",
     "extensions/purescript",
     "extensions/ruby",
+    "extensions/snippets",
     "extensions/svelte",
     "extensions/terraform",
     "extensions/toml",

extensions/snippets/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "zed_snippets"
+version = "0.0.1"
+edition = "2021"
+publish = false
+license = "Apache-2.0"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/snippets.rs"
+crate-type = ["cdylib"]
+
+[dependencies]
+zed_extension_api = "0.0.6"
+serde_json = "1.0"

extensions/snippets/LICENSE-APACHE

@@ -0,0 +1 @@
+../../LICENSE-APACHE

extensions/snippets/extension.toml

@@ -0,0 +1,12 @@
+id = "snippets"
+name = "Snippets"
+description = "Support for language-agnostic snippets, provided by simple-completion-language-server"
+version = "0.0.1"
+schema_version = 1
+authors = []
+repository = "https://github.com/zed-extensions/svelte"
+
+[language_servers.snippet-completion-server]
+name = "Snippet Completion Server"
+languages = ["TypeScript", "TSX", "JavaScript", "JSDoc", "Go", "Markdown", "Rust", "C", "C++", "PHP", "Python", "Ruby", "Shell"]
+language_ids = { "TypeScript" = "typescript", "TSX" = "typescriptreact", "JavaScript" = "javascript" }

extensions/snippets/src/snippets.rs

@@ -0,0 +1,138 @@
+use serde_json::json;
+use std::fs;
+use zed::LanguageServerId;
+use zed_extension_api::{self as zed, Result};
+
+struct SnippetExtension {
+    cached_binary_path: Option<String>,
+}
+
+impl SnippetExtension {
+    fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<String> {
+        if let Some(path) = worktree.which("simple-completion-language-server") {
+            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(
+            "zed-industries/simple-completion-language-server",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        )?;
+
+        let (platform, arch) = zed::current_platform();
+        let asset_name = format!(
+            "simple-completion-language-server-{arch}-{os}.tar.gz",
+            arch = match arch {
+                zed::Architecture::Aarch64 => "aarch64",
+                zed::Architecture::X86 => "x86",
+                zed::Architecture::X8664 => "x86_64",
+            },
+            os = match platform {
+                zed::Os::Mac => "apple-darwin",
+                zed::Os::Linux => "unknown-linux-musl",
+                zed::Os::Windows => "pc-windows-msvc",
+            },
+        );
+
+        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!("simple-completion-language-server-{}", release.version);
+        let binary_path = format!("{version_dir}/simple-completion-language-server");
+
+        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::GzipTar,
+            )
+            .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)
+    }
+}
+
+impl zed::Extension for SnippetExtension {
+    fn new() -> Self {
+        Self {
+            cached_binary_path: None,
+        }
+    }
+
+    fn language_server_command(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<zed::Command> {
+        Ok(zed::Command {
+            command: self.language_server_binary_path(language_server_id, worktree)?,
+            args: vec![],
+            env: vec![("SCLS_CONFIG_SUBDIRECTORY".to_owned(), "zed".to_owned())],
+        })
+    }
+
+    fn language_server_initialization_options(
+        &mut self,
+        _language_server_id: &LanguageServerId,
+        _worktree: &zed_extension_api::Worktree,
+    ) -> Result<Option<zed_extension_api::serde_json::Value>> {
+        Ok(Some(json!({
+            "max_completion_items": 20,
+            "snippets_first": true,
+            "feature_words": false,
+            "feature_snippets": true,
+            "feature_paths": true
+        })))
+    }
+
+    fn language_server_workspace_configuration(
+        &mut self,
+        _language_server_id: &LanguageServerId,
+        _worktree: &zed_extension_api::Worktree,
+    ) -> Result<Option<zed_extension_api::serde_json::Value>> {
+        Ok(Some(json!({
+            "max_completion_items": 20,
+            "snippets_first": true,
+            "feature_words": false,
+            "feature_snippets": true,
+            "feature_paths": true
+        })))
+    }
+}
+
+zed::register_extension!(SnippetExtension);