* Full bash syntax support for pre-/post-build commands on UNIX systems

* Environment variables for pre-/post-build commands which give the user access to several build process parameters like the sketch, the output directory, serial port, build mode (verify, upload, analyze, ...), board type and workspace path
Addresses microsoft#786

Author: elektronikworkshop

src/arduino/arduino.ts

@@ -133,8 +133,7 @@ export class ArduinoApp {
     public async setPref(key, value) {
         try {
             await util.spawn(this._settings.commandPath,
-                null,
-                ["--pref", `${key}=${value}`, "--save-prefs"]);
+                             ["--pref", `${key}=${value}`, "--save-prefs"]);
         } catch (ex) {
         }
     }
@@ -414,21 +413,34 @@ Please make sure the folder is not occupied by other procedures .`);
      * @returns True if successful, false on error.
      */
     protected async runPrePostBuildCommand(dc: DeviceContext,
+                                           environment: any,
                                            what: "pre" | "post"): Promise<boolean> {
         const cmdline = what === "pre"
             ? dc.prebuild
             : dc.postbuild;
 
         if (cmdline) {
             arduinoChannel.info(`Running ${what}-build command: "${cmdline}"`);
-            // TODO 2020-02-27, EW: We could call bash -c "cmd" here at least for
-            //   UNIX systems. Windows users must live with their poor system :)
-            const args = cmdline.split(/\s+/);
-            const cmd = args.shift();
+            let cmd: string;
+            let args: string[];
+            // pre-/post-build commands feature full bash support on UNIX systems.
+            // Windows users must live with their poor system unless someone is
+            // willing to fight with the annoying Windows cmd escaping -- good luck!
+            if (os.platform() === "win32") {
+                args = cmdline.split(/\s+/);
+                cmd = args.shift();
+            } else {
+                args = ["-c", cmdline];
+                cmd = "bash";
+            }
             try {
                 await util.spawn(cmd,
                                  args,
-                                 { shell: true, cwd: ArduinoWorkspace.rootPath },
+                                 {
+                                     shell: os.platform() === "win32",
+                                     cwd: ArduinoWorkspace.rootPath,
+                                     env: {...environment},
+                                 },
                                  { channel: arduinoChannel.channel });
             } catch (ex) {
                 const msg = ex.error
@@ -533,23 +545,38 @@ Please make sure the folder is not occupied by other procedures .`);
         arduinoChannel.start(`${mode} sketch '${dc.sketch}'`);
 
         if (buildDir || dc.output) {
-            const outputPath = path.resolve(ArduinoWorkspace.rootPath, buildDir || dc.output);
-            const dirPath = path.dirname(outputPath);
+            buildDir = path.resolve(ArduinoWorkspace.rootPath, buildDir || dc.output);
+            const dirPath = path.dirname(buildDir);
             if (!util.directoryExistsSync(dirPath)) {
-                logger.notifyUserError("InvalidOutPutPath", new Error(constants.messages.INVALID_OUTPUT_PATH + outputPath));
+                logger.notifyUserError("InvalidOutPutPath", new Error(constants.messages.INVALID_OUTPUT_PATH + buildDir));
                 return false;
             }
-            args.push("--pref", `build.path=${outputPath}`);
-            arduinoChannel.info(`Please see the build logs in output path: ${outputPath}`);
+            args.push("--pref", `build.path=${buildDir}`);
+            arduinoChannel.info(`Please see the build logs in output path: ${buildDir}`);
         } else {
             const msg = "Output path is not specified. Unable to reuse previously compiled files. Build will be slower. See README.";
             arduinoChannel.warning(msg);
         }
 
+        // Environment variables passed to pre- and post-build commands
+        const env = {
+            VSCA_BUILD_MODE: mode,
+            VSCA_SKETCH: dc.sketch,
+            VSCA_BOARD: boardDescriptor,
+            VSCA_WORKSPACE_DIR: ArduinoWorkspace.rootPath,
+            VSCA_LOG_LEVEL: verbose ? constants.LogLevel.Verbose : constants.LogLevel.Info,
+        };
+        if (dc.port) {
+            env["VSCA_SERIAL"] = dc.port;
+        }
+        if (buildDir) {
+            env["VSCA_BUILD_DIR"] = buildDir;
+        }
+
         // TODO EW: What should we do with pre-/post build commands when running
         //   analysis? Some could use it to generate/manipulate code which could
         //   be a prerequisite for a successful build
-        if (!await this.runPrePostBuildCommand(dc, "pre")) {
+        if (!await this.runPrePostBuildCommand(dc, env, "pre")) {
             return false;
         }
 
@@ -566,7 +593,7 @@ Please make sure the folder is not occupied by other procedures .`);
         const cleanup = async (result: "ok" | "error") => {
             let ret = true;
             if (result === "ok") {
-                ret = await this.runPrePostBuildCommand(dc, "post");
+                ret = await this.runPrePostBuildCommand(dc, env, "post");
             }
             await cocopa.conclude();
             if (mode === BuildMode.Upload || mode === BuildMode.UploadProgrammer) {
@@ -618,7 +645,7 @@ Please make sure the folder is not occupied by other procedures .`);
             undefined,
             { stdout: stdoutcb, stderr: stderrcb },
         ).then(async () => {
-            const ret = await cleanup("ok"); 
+            const ret = await cleanup("ok");
             if (ret) {
                 arduinoChannel.end(`${mode} sketch '${dc.sketch}'${os.EOL}`);
             }

src/common/util.ts

@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
-import * as childProcess from "child_process";
+import * as child_process from "child_process";
 import * as fs from "fs";
 import * as iconv from "iconv-lite";
 import * as os from "os";
@@ -187,18 +187,18 @@ export function isArduinoFile(filePath): boolean {
 
 export function spawn(command: string,
                       args: string[] = [],
-                      options: any = {},
+                      options: child_process.SpawnOptions = {},
                       output?: {channel?: vscode.OutputChannel,
                                 stdout?: (string) => void,
                                 stderr?: (string) => void}): Thenable<object> {
     return new Promise((resolve, reject) => {
         options.cwd = options.cwd || path.resolve(path.join(__dirname, ".."));
-        const child = childProcess.spawn(command, args, options);
+        const child = child_process.spawn(command, args, options);
 
         let codepage = "65001";
         if (os.platform() === "win32") {
             try {
-                const chcp = childProcess.execSync("chcp.com");
+                const chcp = child_process.execSync("chcp.com");
                 codepage = chcp.toString().split(":").pop().trim();
             } catch (error) {
                 arduinoChannel.warning(`Defaulting to code page 850 because chcp.com failed.\