Fix #264: Check for OpenSSL on OS X before starting Editor Services

This change adds a check when the extension initializes to verify
whether the machine has OpenSSL installed when running on OS X.  This is
currently a requirement of PowerShell which must be met before
PowerShell Editor Services can be started.  If the proper library paths
are not detected, a message is shown to the user which leads them to
documentation on how to install OpenSSL.

Author: daviwil

src/main.ts

@@ -112,6 +112,26 @@ export function activate(context: vscode.ExtensionContext): void {
     }
     else if (os.platform() == "darwin") {
         powerShellExePath = "/usr/local/bin/powershell";
+
+        // Check for OpenSSL dependency on OS X
+        if (!utils.checkIfFileExists("/usr/local/lib/libcrypto.1.0.0.dylib") ||
+            !utils.checkIfFileExists("/usr/local/lib/libssl.1.0.0.dylib")) {
+                var thenable =
+                    vscode.window.showWarningMessage(
+                        "The PowerShell extension will not work without OpenSSL on Mac OS X",
+                        "Show Documentation");
+
+                thenable.then(
+                    (s) => {
+                        if (s === "Show Documentation") {
+                            cp.exec("open https://github.com/PowerShell/vscode-powershell/blob/master/docs/troubleshooting.md#1-powershell-intellisense-does-not-work-cant-debug-scripts");
+                        }
+                    });
+
+                // Don't continue initializing since Editor Services will not load successfully
+                console.log("Cannot start PowerShell Editor Services due to missing OpenSSL dependency.");
+                return;
+            }
     }
     else {
         powerShellExePath = "/usr/bin/powershell";

src/utils.ts

@@ -79,4 +79,14 @@ export function readSessionFile(): EditorServicesSessionDetails {
 
 export function deleteSessionFile() {
     fs.unlinkSync(sessionFilePath);
+}
+
+export function checkIfFileExists(filePath: string): boolean {
+    try {
+        fs.accessSync(filePath, fs.R_OK)
+        return true;
+    }
+    catch (e) {
+        return false;
+    }
 }