Make temporary build filename user specific to prevent conflict on sy…

…stems with shared temp folders (#1835)

* fixes #1829

* Added a function to generate a hash based on the current users username

* forgot to lint

src/goBuild.ts

@@ -5,6 +5,7 @@ import { outputChannel } from './goStatus';
 import os = require('os');
 import { getNonVendorPackages } from './goPackages';
 import { getTestFlags } from './testUtils';
+import { getUsernameHash } from './util';
 import { getCurrentGoWorkspaceFromGOPATH } from './goPath';
 import { diagnosticsStatusBarItem } from './goStatus';
 /**
@@ -56,7 +57,7 @@ export function goBuild(fileUri: vscode.Uri, goConfig: vscode.WorkspaceConfigura
 	}
 
 	const buildEnv = Object.assign({}, getToolsEnvVars());
-	const tmpPath = path.normalize(path.join(os.tmpdir(), 'go-code-check'));
+	const tmpPath = path.normalize(path.join(os.tmpdir(), 'go-code-check.' + getUsernameHash()));
 	const isTestFile = fileUri && fileUri.fsPath.endsWith('_test.go');
 	const buildFlags: string[] = isTestFile ? getTestFlags(goConfig, null) : (Array.isArray(goConfig['buildFlags']) ? [...goConfig['buildFlags']] : []);
 	const buildArgs: string[] = isTestFile ? ['test', '-c'] : ['build'];

src/util.ts

@@ -178,6 +178,25 @@ export function canonicalizeGOPATHPrefix(filename: string): string {
 	return currentWorkspace + filename.slice(currentWorkspace.length);
 }
 
+/**
+ * Gets a numeric hash based on the current users username.
+ * Returns a number between 0 and 4294967295.
+ */
+export function getUsernameHash(): number {
+	const user: string = os.userInfo().username;
+	let hash = 5381,
+			i    = user.length;
+
+	while (i) {
+		hash = (hash * 33) ^ user.charCodeAt(--i);
+	}
+
+	/* JavaScript does bitwise operations (like XOR, above) on 32-bit signed
+		* integers. Since we want the results to be always positive, convert the
+		* signed int to an unsigned by doing an unsigned bitshift. */
+	return hash >>> 0;
+}
+
 /**
  * Gets version of Go based on the output of the command `go version`.
  * Returns null if go is being used from source/tip in which case `go version` will not return release tag like go1.6.3