Toolchain handling II (#43)

* Improve ongoing toolchain updates and checks
  - Check a toolchain has rls before install
  - Provide hint to latest dated toolchain with rls
  - Allow updating from dated toolchain
* Improve eslint rules + jsdoc
* Add new toolchain handling features to readme
* Restart servers after installation
* Update to atom-languageclient 0.8.2
* Add check for updates every 6 hours
* Add check for updates when enabling update checking config

Author: alexheretic

.eslintrc.js

@@ -6,8 +6,13 @@ module.exports = {
     browser: true,
   },
   rules: {
-    semi: ["error", "never"],
+    semi: ["warn", "never"],
     "no-console": "off",
+    "valid-jsdoc": ["warn", {
+      requireParamDescription: false,
+      requireReturn: false,
+      requireReturnDescription: false,
+    }],
   },
   globals: {
     atom: true,

README.md

@@ -15,6 +15,9 @@ Rust language support for Atom-IDE, powered by the Rust Language Server (RLS).
    # rls.toml
    features = ["serde"]
    ```
+ - Graceful handling of Rls being missing from the distribution _(which is somewhat common on the nightly channel)_
+   * Warns before installing a rust version without Rls or when using an already installed one
+   * Automatic detection of, and prompt to install, the latest working dated release
 
 ## Install
 You can install from the command line with:

lib/dist-fetch.js

@@ -0,0 +1,109 @@
+const https = require('https')
+const _ = require('underscore-plus')
+
+const datedNightlyHasRlsCache = new Map()
+const DATED_REGEX = /(^[^-]+)-(\d{4,}-\d{2}-\d{2})$/
+
+/**
+ * @param {Date|string} date
+ * @param {string=} channel
+ * @return {Promise<string>} toolchain name
+ */
+function checkDatedNightlyHasRls(date, channel='nightly') {
+  const dateString = _.isString(date) ? date : date.toISOString().split('T')[0]
+  const cacheKey = `${channel}-${dateString}`
+
+  let fetch = datedNightlyHasRlsCache.get(cacheKey) || new Promise((resolve, reject) => {
+    https.get(`https://static.rust-lang.org/dist/${dateString}/channel-rust-${channel}.toml`, res => {
+        if (res.statusCode !== 200) {
+          return reject(new Error(`Failed, status: ${res.statusCode}`))
+        }
+        res.setEncoding("utf8")
+        let body = ""
+        res.on("data", data => {
+          body += data
+          if (body.includes('rls-preview')) resolve(cacheKey)
+        })
+        res.on("end", () => reject(new Error("no 'rls-preview'")))
+      })
+      .on("error", e => {
+        datedNightlyHasRlsCache.delete(cacheKey)
+        reject(e)
+      })
+  })
+
+  if (!datedNightlyHasRlsCache.has(cacheKey)) {
+    datedNightlyHasRlsCache.set(cacheKey, fetch)
+  }
+
+  return fetch
+}
+
+/** @return {Promise<string>} latest nightly dated version with rls-preview */
+function fetchLatestDatedNightlyWithRls() {
+  const aDayMillis = 24 * 60 * 60 * 1000
+  const minDate = new Date(Date.now() - 30 * aDayMillis)
+
+  const check = day => {
+    return checkDatedNightlyHasRls(day)
+      .catch(e => {
+        if (e && e.code === 'ENOTFOUND') throw e
+
+        const yesterday = new Date(day - aDayMillis)
+        if (yesterday >= minDate) return check(yesterday)
+        else throw new Error("No nightly with 'rls-preview'")
+      })
+  }
+
+  return check(new Date())
+}
+
+/**
+ * @param {string} arg.toolchain toolchain to check
+ * @param {string} [arg.currentVersion] current installed rustc version
+ * @return {Promise<?string>} new version of update available (falsy otherwise)
+ */
+function fetchLatestDist({ toolchain, currentVersion="none" }) {
+  return new Promise((resolve, reject) => {
+    https.get(`https://static.rust-lang.org/dist/channel-rust-${toolchain}.toml`, res => {
+      if (res.statusCode !== 200) {
+        return reject(new Error(`check for toolchain update failed, status: ${res.statusCode}`))
+      }
+
+      res.setEncoding("utf8")
+      let body = ""
+      res.on("data", data => body += data)
+      res.on("end", () => {
+        // use a subsection as toml is slow to parse fully
+        let rustcInfo = body.match(/(\[pkg\.rustc\][^[]*)/m)
+        if (!rustcInfo) return reject(new Error('could not split channel toml output'))
+        let rustcVersion = require('toml').parse(rustcInfo[1]).pkg.rustc.version.trim()
+        resolve(
+          !currentVersion.trim().endsWith(rustcVersion) &&
+          body.includes('rls-preview') &&
+          `rustc ${rustcVersion}`
+        )
+      })
+    })
+  })
+}
+
+/**
+ * Check a toolchain has rls, this can be done before installing
+ * @param {string} toolchain
+ * @return {Promise<boolean>}
+ */
+function checkHasRls(toolchain) {
+  let dated = toolchain.match(DATED_REGEX)
+  if (dated) {
+    return checkDatedNightlyHasRls(dated[2], dated[1]).then(() => true).catch(() => false)
+  }
+  return fetchLatestDist({ toolchain }).then(v => !!v).catch(() => false)
+}
+
+module.exports = {
+  fetchLatestDatedNightlyWithRls,
+  fetchLatestDist,
+  checkHasRls,
+  DATED_REGEX,
+}