Handle clang-tidy functionality.

Fixes issue #4579
This is a new linter for C/C++.

Signed-off-by: Jacques Bouthillier <[email protected]>

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Change Log
 
 ## v0.5.0
+- [cpp] added new clang-tidy and clang-tidy-checks preferences to lint cpp program.
 - [plugin] `workspace.openTextDocument` API now respects the contributed `FileSystemProviders`
 
 Breaking changes:

packages/cpp/README.md

@@ -79,6 +79,28 @@ To get this working, you need to enable clangd's global index using the
             "cpp.clangdArgs": "--background-index"
         }
 
+## Using the clang-tidy linter
+
+Note: This functionality is available when using clangd 9 and later.
+
+You can set the preference 'cpp.clang-tidy' to initiate the linter. When the preference is set, there are two possibilities to pass the checks arguments:
+
+- using the preferences:  'cpp.clang-tidy-checks'
+- using the file '.clang-tidy' . The file is located in the same folder of the files or a parent folder.
+
+Note: using the preference checks will supersede the value found in the .clang-tidy file.
+
+The syntax used to fill the checks can be found at http://clang.llvm.org/extra/clang-tidy/
+
+clang-tidy has its own checks and can also run Clang static analyzer checks. Each check has a name and the checks to run can be chosen using the -checks= option, which specifies a comma-separated list of positive and negative (prefixed with -) globs. Positive globs add subsets of checks, negative globs remove them. For example,
+
+    - Example for the preferences: "cpp.clang-tidy-checks": "*,-readability-*"
+        - Meaning: enables all list-checks and disable all readability-* checks
+
+    - Example for the .clang-tidy file: Checks: -*,readability-*
+        - Meaning: disable all list-checks and enable all readability-* checks
+
 ## License
+
 - [Eclipse Public License 2.0](http://www.eclipse.org/legal/epl-2.0/)
 - [一 (Secondary) GNU General Public License, version 2 with the GNU Classpath Exception](https://projects.eclipse.org/license/secondary-gpl-2.0-cp)

packages/cpp/src/browser/cpp-language-client-contribution.ts

@@ -140,7 +140,9 @@ export class CppLanguageClientContribution extends BaseLanguageClientContributio
     protected getStartParameters(): CppStartParameters {
         return {
             clangdExecutable: this.cppPreferences['cpp.clangdExecutable'],
-            clangdArgs: this.cppPreferences['cpp.clangdArgs']
+            clangdArgs: this.cppPreferences['cpp.clangdArgs'],
+            clangTidy: this.cppPreferences['cpp.clangTidy'],
+            clangTidyChecks: this.cppPreferences['cpp.clangTidyChecks']
         };
     }
 }

packages/cpp/src/browser/cpp-preferences.ts

@@ -61,6 +61,16 @@ export const cppPreferencesSchema: PreferenceSchema = {
             description: 'Specify the arguments to pass to clangd when starting the language server.',
             default: '',
             type: 'string'
+        },
+        'cpp.clangTidy': {
+            description: 'Enable/disable C/C++ linting.',
+            default: false,
+            type: 'boolean'
+        },
+        'cpp.clangTidyChecks': {
+            description: 'Specify comma separated arguments to pass to clang-tidy. Activated only if cpp.clang-tidy is enabled',
+            default: '',
+            type: 'string'
         }
     }
 };
@@ -70,6 +80,8 @@ export class CppConfiguration {
     'cpp.experimentalCommands': boolean;
     'cpp.clangdExecutable': string;
     'cpp.clangdArgs': string;
+    'cpp.clangTidy': boolean;
+    'cpp.clangTidyChecks': string;
 }
 
 export const CppPreferences = Symbol('CppPreferences');

packages/cpp/src/common/index.ts

@@ -27,4 +27,6 @@ export const CLANGD_EXECUTABLE_DEFAULT = 'clangd';
 export interface CppStartParameters {
     clangdExecutable: string;
     clangdArgs: string;
+    clangTidy?: boolean;
+    clangTidyChecks?: string;
 }

packages/cpp/src/node/cpp-contribution.ts

@@ -1,5 +1,5 @@
 /********************************************************************************
- * Copyright (C) 2017 Ericsson and others.
+ * Copyright (C) 2017-2019 Ericsson and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -42,7 +42,34 @@ export class CppContribution extends BaseLanguageServerContribution {
             || undefined
         );
 
+        const clangTidy = parameters && parameters.clangTidy;
+        const clangTidyChecks = parameters && parameters.clangTidyChecks;
+
+        if (clangTidy) {
+            const supportsClangTidy = await this.testSupportsClangTidy(command);
+            if (supportsClangTidy) {
+                args.push('-clang-tidy');
+                if (typeof clangTidyChecks === 'string' && clangTidyChecks.length > 0) {
+                    args.push(`-clang-tidy-checks=${clangTidyChecks}`);
+                }
+            }
+        }
         const serverConnection = await this.createProcessStreamConnectionAsync(command, args);
         this.forward(clientConnection, serverConnection);
     }
+
+    protected async testSupportsClangTidy(command: string): Promise<boolean> {
+        // clangd should fail if -clang-tidy flag is not supported
+        // but if it is supported, it will run forever until killed/stopped.
+        // to avoid that, we pass -version flag which makes it exit early.
+        const process = await super.spawnProcessAsync(command, ['-clang-tidy', '-version']);
+        return new Promise<boolean>(resolve => {
+            process.errorOutput.on('data', (data: string) => {
+                if (data.includes('-clang-tidy')) {
+                    resolve(false);
+                }
+            });
+            process.errorOutput.once('close', () => resolve(true));
+        });
+    }
 }