Observe all settings

Getting the settings every single lint call is needlessly expensive.
Observe the settings so we are fed the value at the start, and on every
change.

Author: Arcanemagus

lib/main.js

@@ -1,28 +1,76 @@
 'use babel';
 
+// eslint-disable-next-line import/extensions, import/no-extraneous-dependencies
+import { CompositeDisposable } from 'atom';
+
 let helpers = null;
 let clangFlags = null;
 
 export default {
   activate() {
     require('atom-package-deps').install('linter-clang');
+    this.subscriptions = new CompositeDisposable();
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.execPath', (value) => {
+        this.execPath = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangIncludePaths', (value) => {
+        this.clangIncludePaths = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangSuppressWarnings', (value) => {
+        this.clangSuppressWarnings = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangDefaultCFlags', (value) => {
+        this.clangDefaultCFlags = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangDefaultCppFlags', (value) => {
+        this.clangDefaultCppFlags = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangDefaultObjCFlags', (value) => {
+        this.clangDefaultObjCFlags = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangDefaultObjCppFlags', (value) => {
+        this.clangDefaultObjCppFlags = value;
+      }),
+    );
+    this.subscriptions.add(
+      atom.config.observe('linter-clang.clangErrorLimit', (value) => {
+        this.clangErrorLimit = value;
+      }),
+    );
+  },
+
+  deactivate() {
+    this.subscriptions.dispose();
   },
 
   provideLinter() {
     const regex = '(?<file>.+):(?<line>\\d+):(?<col>\\d+):({(?<lineStart>\\d+):(?<colStart>\\d+)-(?<lineEnd>\\d+):(?<colEnd>\\d+)}.*:)? (?<type>[\\w \\-]+): (?<message>.*)';
     return {
       name: 'clang',
-      grammarScopes: ['source.c', 'source.cpp', 'source.objc', 'source.objcpp'],
       scope: 'file',
       lintOnFly: false,
+      grammarScopes: ['source.c', 'source.cpp', 'source.objc', 'source.objcpp'],
       lint: (activeEditor) => {
         if (helpers === null) {
           helpers = require('atom-linter');
         }
         if (clangFlags === null) {
           clangFlags = require('clang-flags');
         }
-        const command = atom.config.get('linter-clang.execPath');
+
         const filePath = activeEditor.getPath();
         const args = [
           '-fsyntax-only',
@@ -36,30 +84,30 @@ export default {
 
         if (/^C\+\+/.test(grammar)) {
           args.push('-xc++');
-          args.push(...atom.config.get('linter-clang.clangDefaultCppFlags').split(/\s+/));
+          args.push(...this.clangDefaultCppFlags.split(/\s+/));
         }
         if (grammar === 'Objective-C++') {
           args.push('-xobjective-c++');
-          args.push(...atom.config.get('linter-clang.clangDefaultObjCppFlags').split(/\s+/));
+          args.push(...this.clangDefaultObjCppFlags.split(/\s+/));
         }
         if (grammar === 'C') {
           args.push('-xc');
-          args.push(...atom.config.get('linter-clang.clangDefaultCFlags').split(/\s+/));
+          args.push(...this.clangDefaultCFlags.split(/\s+/));
         }
         if (grammar === 'Objective-C') {
           args.push('-xobjective-c');
-          args.push(...atom.config.get('linter-clang.clangDefaultObjCFlags').split(/\s+/));
+          args.push(...this.clangDefaultObjCFlags.split(/\s+/));
         }
 
-        args.push(`-ferror-limit=${atom.config.get('linter-clang.clangErrorLimit')}`);
-        if (atom.config.get('linter-clang.clangSuppressWarnings')) {
+        args.push(`-ferror-limit=${this.clangErrorLimit}`);
+        if (this.clangSuppressWarnings) {
           args.push('-w');
         }
         if (atom.inDevMode()) {
           args.push('--verbose');
         }
 
-        atom.config.get('linter-clang.clangIncludePaths').forEach(path =>
+        this.clangIncludePaths.forEach(path =>
           args.push(`-I${path}`),
         );
 
@@ -81,7 +129,7 @@ export default {
           allowEmptyStderr: true,
         };
 
-        return helpers.exec(command, args, execOpts).then(output =>
+        return helpers.exec(this.execPath, args, execOpts).then(output =>
           helpers.parse(output, regex),
         );
       },