/// Copyright 2014 Google Inc. All rights reserved.
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///    http://www.apache.org/licenses/LICENSE-2.0
///
///    Unless required by applicable law or agreed to in writing, software
///    distributed under the License is distributed on an "AS IS" BASIS,
///    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
///    See the License for the specific language governing permissions and
///    limitations under the License.

/**
*  A validating XPC connection/listener which uses codesigning to validate that both ends of the
*  connection were signed by the same certificate chain.
*
*  Example server started by @c launchd where the @c launchd job has a @c MachServices key:
*
*@code
*   SNTXPCConnection *conn = [[SNTXPCConnection alloc] initServerWithName:@"MyServer"];
*   conn.exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(MyServerProtocol)];
*   conn.exportedObject = myObject;
*   conn.remoteInterface = [NSXPCInterface interfaceWithProtocol:@protocol(MyClientProtocol)];
*   [conn resume];
*@endcode
*
*  Example client, connecting to above server:
*
*@code
*   SNTXPCConnection *conn = [[SNTXPCConnection alloc] initClientWithName:"MyServer" withOptions:0];
*   conn.exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(MyClientProtocol)];
*   conn.exportedObject = myObject;
*   conn.remoteInterface = [NSXPCInterface interfaceWithProtocol:@protocol(MyServerProtocol)];
*   conn.invalidationHandler = ^{ NSLog(@"Connection invalidated") };
*   [conn resume];
*@endcode
*
*  Either side can then send a message to the other with:
*
*@code
*   [conn.remoteObjectProxy selectorInRemoteInterface];
*@endcode
*
*  Note: messages are always delivered on a background thread!
**/
@interface SNTXPCConnection : NSObject<NSXPCListenerDelegate>

typedef void (^SNTXPCInvalidationBlock)(void);
typedef void (^SNTXPCAcceptedBlock)(void);
typedef void (^SNTXPCRejectedBlock)(void);

/// The interface the remote object should conform to.
@property(retain) NSXPCInterface *remoteInterface;

/// A proxy to the object at the other end of the connection.
/// *Warning*: Do not send a message to this object if you didn't set @c remoteInterface above
/// before calling the @c resume method, doing so will throw an exception.
@property(readonly) id remoteObjectProxy;

/// The interface this object conforms to.
@property(retain) NSXPCInterface *exportedInterface;

/// The object that responds to messages from the other end.
@property(retain) id exportedObject;

/// A block to run when the connection is invalidated.
@property(copy) SNTXPCInvalidationBlock invalidationHandler;

/// A block to run when the connection has been accepted.
@property(copy) SNTXPCAcceptedBlock acceptedHandler;

/// A block to run when the connection has been rejected.
@property(copy) SNTXPCRejectedBlock rejectedHandler;

/// Initializer for the 'server' side of the connection, the binary that was started by launchd.
- (instancetype)initServerWithName:(NSString *)name;

/// Initializer for the 'client' side of the connection. If the 'server' was started as a
/// LaunchDaemon (running as root), pass |NSXPCConnectionPrivileged| for |options|, otherwise use 0.
- (instancetype)initClientWithName:(NSString *)name options:(NSXPCConnectionOptions)options;

/// Call when the properties of the object have been set-up and you're ready for connections.
- (void)resume;

@end