Add FBPortForwarding source code

Summary:
See FBPortForwarding/README.md for an explanation of what this is.
It's required for the upcoming support for physical iOS devices.

To simplify development of the JS app, We're going to bundle the pre-built PortForwardingMacApp
inside the repo, and inside the electron app (static/PortForwardingMacApp.app).
Adding this source so users can build it from source if they choose to.

Reviewed By: danielbuechele

Differential Revision: D13276022

fbshipit-source-id: 99b18e0412cf443bb4a67eb4846cc780e0014de1

PortForwardingMacApp/main.m

@@ -0,0 +1,34 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#import <Foundation/Foundation.h>
+
+#import <FKPortForwarding/FKPortForwardingClient.h>
+
+static const char kPortForwardParamPrefix[] = "-portForward=";
+static const char kMultiplexChannelPortParamPrefix[] = "-multiplexChannelPort=";
+
+static BOOL prefix(const char *pre, const char *str) {
+    return strncmp(pre, str, strlen(pre)) == 0;
+}
+
+int main(int argc, char *argv[])
+{
+  long connectionsPort = 8081;
+  long multiplexPort = 8025;
+
+  for (int i = 1; i < argc; ++i) {
+    if (prefix(kPortForwardParamPrefix, argv[i])) {
+      connectionsPort = strtol(argv[i] + strlen(kPortForwardParamPrefix), NULL, 10);
+    } else if (prefix(kMultiplexChannelPortParamPrefix, argv[i])) {
+      multiplexPort = strtol(argv[i] + strlen(kMultiplexChannelPortParamPrefix), NULL, 10);
+    }
+  }
+
+  FKPortForwardingClient *client = [FKPortForwardingClient new];
+  [client forwardConnectionsToPort:connectionsPort];
+  [client connectToMultiplexingChannelOnPort:multiplexPort];
+
+  [[NSRunLoop currentRunLoop] run];
+  client = nil;
+  return 0;
+}