chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/languages/src/json.rs

@@ -0,0 +1,198 @@
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use collections::HashMap;
+use feature_flags::FeatureFlagAppExt;
+use futures::StreamExt;
+use gpui::AppContext;
+use language::{LanguageRegistry, LanguageServerName, LspAdapter, LspAdapterDelegate};
+use lsp::LanguageServerBinary;
+use node_runtime::NodeRuntime;
+use serde_json::{json, Value};
+use settings::{KeymapFile, SettingsJsonSchemaParams, SettingsStore};
+use smol::fs;
+use std::{
+    any::Any,
+    ffi::OsString,
+    path::{Path, PathBuf},
+    sync::{Arc, OnceLock},
+};
+use util::{async_maybe, paths, ResultExt};
+
+const SERVER_PATH: &'static str =
+    "node_modules/vscode-json-languageserver/bin/vscode-json-languageserver";
+
+fn server_binary_arguments(server_path: &Path) -> Vec<OsString> {
+    vec![server_path.into(), "--stdio".into()]
+}
+
+pub struct JsonLspAdapter {
+    node: Arc<dyn NodeRuntime>,
+    languages: Arc<LanguageRegistry>,
+    workspace_config: OnceLock<Value>,
+}
+
+impl JsonLspAdapter {
+    pub fn new(node: Arc<dyn NodeRuntime>, languages: Arc<LanguageRegistry>) -> Self {
+        Self {
+            node,
+            languages,
+            workspace_config: Default::default(),
+        }
+    }
+
+    fn get_workspace_config(language_names: Vec<String>, cx: &mut AppContext) -> Value {
+        let action_names = cx.all_action_names();
+        let staff_mode = cx.is_staff();
+
+        let font_names = &cx.text_system().all_font_names();
+        let settings_schema = cx.global::<SettingsStore>().json_schema(
+            &SettingsJsonSchemaParams {
+                language_names: &language_names,
+                staff_mode,
+                font_names,
+            },
+            cx,
+        );
+        let tasks_schema = task::static_source::DefinitionProvider::generate_json_schema();
+        serde_json::json!({
+            "json": {
+                "format": {
+                    "enable": true,
+                },
+                "schemas": [
+                    {
+                        "fileMatch": [
+                            schema_file_match(&paths::SETTINGS),
+                            &*paths::LOCAL_SETTINGS_RELATIVE_PATH,
+                        ],
+                        "schema": settings_schema,
+                    },
+                    {
+                        "fileMatch": [schema_file_match(&paths::KEYMAP)],
+                        "schema": KeymapFile::generate_json_schema(&action_names),
+                    },
+                    {
+                        "fileMatch": [schema_file_match(&paths::TASKS)],
+                        "schema": tasks_schema,
+                    }
+                ]
+            }
+        })
+    }
+}
+
+#[async_trait]
+impl LspAdapter for JsonLspAdapter {
+    fn name(&self) -> LanguageServerName {
+        LanguageServerName("json-language-server".into())
+    }
+
+    fn short_name(&self) -> &'static str {
+        "json"
+    }
+
+    async fn fetch_latest_server_version(
+        &self,
+        _: &dyn LspAdapterDelegate,
+    ) -> Result<Box<dyn 'static + Send + Any>> {
+        Ok(Box::new(
+            self.node
+                .npm_package_latest_version("vscode-json-languageserver")
+                .await?,
+        ) as Box<_>)
+    }
+
+    async fn fetch_server_binary(
+        &self,
+        version: Box<dyn 'static + Send + Any>,
+        container_dir: PathBuf,
+        _: &dyn LspAdapterDelegate,
+    ) -> Result<LanguageServerBinary> {
+        let version = version.downcast::<String>().unwrap();
+        let server_path = container_dir.join(SERVER_PATH);
+
+        if fs::metadata(&server_path).await.is_err() {
+            self.node
+                .npm_install_packages(
+                    &container_dir,
+                    &[("vscode-json-languageserver", version.as_str())],
+                )
+                .await?;
+        }
+
+        Ok(LanguageServerBinary {
+            path: self.node.binary_path().await?,
+            env: None,
+            arguments: server_binary_arguments(&server_path),
+        })
+    }
+
+    async fn cached_server_binary(
+        &self,
+        container_dir: PathBuf,
+        _: &dyn LspAdapterDelegate,
+    ) -> Option<LanguageServerBinary> {
+        get_cached_server_binary(container_dir, &*self.node).await
+    }
+
+    async fn installation_test_binary(
+        &self,
+        container_dir: PathBuf,
+    ) -> Option<LanguageServerBinary> {
+        get_cached_server_binary(container_dir, &*self.node).await
+    }
+
+    fn initialization_options(&self) -> Option<serde_json::Value> {
+        Some(json!({
+            "provideFormatter": true
+        }))
+    }
+
+    fn workspace_configuration(&self, _workspace_root: &Path, cx: &mut AppContext) -> Value {
+        self.workspace_config
+            .get_or_init(|| Self::get_workspace_config(self.languages.language_names(), cx))
+            .clone()
+    }
+
+    fn language_ids(&self) -> HashMap<String, String> {
+        [("JSON".into(), "jsonc".into())].into_iter().collect()
+    }
+}
+
+async fn get_cached_server_binary(
+    container_dir: PathBuf,
+    node: &dyn NodeRuntime,
+) -> Option<LanguageServerBinary> {
+    async_maybe!({
+        let mut last_version_dir = None;
+        let mut entries = fs::read_dir(&container_dir).await?;
+        while let Some(entry) = entries.next().await {
+            let entry = entry?;
+            if entry.file_type().await?.is_dir() {
+                last_version_dir = Some(entry.path());
+            }
+        }
+
+        let last_version_dir = last_version_dir.ok_or_else(|| anyhow!("no cached binary"))?;
+        let server_path = last_version_dir.join(SERVER_PATH);
+        if server_path.exists() {
+            Ok(LanguageServerBinary {
+                path: node.binary_path().await?,
+                env: None,
+                arguments: server_binary_arguments(&server_path),
+            })
+        } else {
+            Err(anyhow!(
+                "missing executable in directory {:?}",
+                last_version_dir
+            ))
+        }
+    })
+    .await
+    .log_err()
+}
+
+fn schema_file_match(path: &Path) -> &Path {
+    path.strip_prefix(path.parent().unwrap().parent().unwrap())
+        .unwrap()
+}