initial commit

ExtensionHelper/main.swift

@@ -0,0 +1,78 @@
+// ExtensionHelper is invoked by the browser extension and killed automatically
+// when all tabs using the extension are closed. It relays incoming messages to
+// the IPCServer running in the main app.
+
+import Cocoa
+import CheetahIPC
+
+let client = try? IPCClient(messagePortName: MessagePortName.browserExtensionServer.rawValue)
+guard let client = client else {
+    exit(1)
+}
+
+let decoder = JSONDecoder()
+decoder.keyDecodingStrategy = .convertFromSnakeCase
+
+let stdin = FileHandle.standardInput
+_ = enableRawMode(fileHandle: stdin)
+
+func handleMessage() throws {
+    // Read length
+    guard let size = stdin.readData(ofLength: 4).value(ofType: UInt32.self, at: 0, convertEndian: true) else {
+        return
+    }
+    
+    // Read message
+    let data = stdin.readData(ofLength: Int(size))
+    _ = try client.sendRequest(msgid: IPCMessage.browserExtensionMessage.rawValue, data: data)
+    
+    //TODO: send response (UInt32 length followed by JSON message)
+}
+
+while true {
+    do {
+        try handleMessage()
+    } catch {
+        exit(1)
+    }
+}
+
+// https://forums.swift.org/t/how-to-read-uint32-from-a-data/59431/11
+extension Data {
+    subscript<T: BinaryInteger>(at offset: Int, convertEndian convertEndian: Bool = false) -> T? {
+        value(ofType: T.self, at: offset, convertEndian: convertEndian)
+    }
+    
+    func value<T: BinaryInteger>(ofType: T.Type, at offset: Int, convertEndian: Bool = false) -> T? {
+        let right = offset &+ MemoryLayout<T>.size
+        guard offset >= 0 && right > offset && right <= count else {
+            return nil
+        }
+        let bytes = self[offset ..< right]
+        if convertEndian {
+            return bytes.reversed().reduce(0) { T($0) << 8 + T($1) }
+        } else {
+            return bytes.reduce(0) { T($0) << 8 + T($1) }
+        }
+    }
+}
+
+// see https://stackoverflow.com/a/24335355/669586
+func initStruct<S>() -> S {
+    let struct_pointer = UnsafeMutablePointer<S>.allocate(capacity: 1)
+    let struct_memory = struct_pointer.pointee
+    struct_pointer.deallocate()
+    return struct_memory
+}
+
+func enableRawMode(fileHandle: FileHandle) -> termios {
+    var raw: termios = initStruct()
+    tcgetattr(fileHandle.fileDescriptor, &raw)
+
+    let original = raw
+
+    raw.c_lflag &= ~(UInt(ECHO | ICANON))
+    tcsetattr(fileHandle.fileDescriptor, TCSAFLUSH, &raw);
+
+    return original
+}