hw: rename functions of Ipc_node class signature

* Remove *request* in context of: wait, reply, send to shorten it.
* Use ready_to_* instead of can_*, which is regularily used in Genode's APIs
* Replace helping_sink with helping_destination, as destination is more common

Ref genodelabs/genode#4704

repos/base-hw/src/core/kernel/cpu.h

@@ -172,7 +172,7 @@ class Kernel::Cpu : public Genode::Cpu, private Irq::Pool, private Timeout
 		 * Returns the currently active job
 		 */
 		Job & scheduled_job() const {
-			return *static_cast<Job *>(&_scheduler.head())->helping_sink(); }
+			return *static_cast<Job *>(&_scheduler.head())->helping_destination(); }
 
 		unsigned id() const { return _id; }
 		Cpu_scheduler &scheduler() { return _scheduler; }

repos/base-hw/src/core/kernel/cpu_context.h

@@ -88,7 +88,7 @@ class Kernel::Cpu_job : private Cpu_share
 		/**
 		 * Return which job currently uses our CPU-share
 		 */
-		virtual Cpu_job * helping_sink() = 0;
+		virtual Cpu_job * helping_destination() = 0;
 
 		/**
 		 * Construct a job with scheduling priority 'p' and time quota 'q'

repos/base-hw/src/core/kernel/ipc_node.cc

@@ -63,13 +63,13 @@ bool Ipc_node::_helping() const
 }
 
 
-bool Ipc_node::can_send_request() const
+bool Ipc_node::ready_to_send() const
 {
 	return _out.state == Out::READY && !_in.waiting();
 }
 
 
-void Ipc_node::send_request(Ipc_node &node, bool help)
+void Ipc_node::send(Ipc_node &node, bool help)
 {
 	node._in.queue.enqueue(_queue_item);
 
@@ -82,19 +82,19 @@ void Ipc_node::send_request(Ipc_node &node, bool help)
 }
 
 
-Thread &Ipc_node::helping_sink()
+Thread &Ipc_node::helping_destination()
 {
-	return _helping() ? _out.node->helping_sink() : _thread;
+	return _helping() ? _out.node->helping_destination() : _thread;
 }
 
 
-bool Ipc_node::can_await_request() const
+bool Ipc_node::ready_to_wait() const
 {
 	return _in.state == In::READY;
 }
 
 
-void Ipc_node::await_request()
+void Ipc_node::wait()
 {
 	_in.state = In::WAIT;
 	_in.queue.head([&] (Queue_item &item) {
@@ -103,7 +103,7 @@ void Ipc_node::await_request()
 }
 
 
-void Ipc_node::send_reply()
+void Ipc_node::reply()
 {
 	if (_in.state == In::REPLY)
 		_in.queue.dequeue([&] (Queue_item &item) {

repos/base-hw/src/core/kernel/ipc_node.h

@@ -89,30 +89,28 @@ class Kernel::Ipc_node
 
 	public:
 
-		/**
-		 * Destructor
-		 */
+		Ipc_node(Thread &thread);
+
 		~Ipc_node();
 
 		/**
-		 * Constructor
+		 * Return whether this IPC node is ready to send a message
 		 */
-		Ipc_node(Thread &thread);
+		bool ready_to_send() const;
 
 		/**
-		 * Send a request and wait for the according reply
+		 * Send a message and wait for the according reply
 		 *
 		 * \param node  targeted IPC node
 		 * \param help  wether the request implies a helping relationship
 		 */
-		bool can_send_request() const;
-		void send_request(Ipc_node &node,
-		                  bool      help);
+		void send(Ipc_node &node, bool help);
 
 		/**
-		 * Return root destination of the helping-relation tree we are in
+		 * Return final destination of the helping-chain
+		 * this IPC node is part of, or its own thread otherwise
 		 */
-		Thread &helping_sink();
+		Thread &helping_destination();
 
 		/**
 		 * Call function 'f' of type 'void (Ipc_node *)' for each helper
@@ -128,24 +126,31 @@ class Kernel::Ipc_node
 		}
 
 		/**
-		 * Wait until a request has arrived and load it for handling
+		 * Return whether this IPC node is ready to wait for messages
+		 */
+		bool ready_to_wait() const;
+
+		/**
+		 * Wait until a message has arrived, or handle it if one is available
 		 *
-		 * \return  wether a request could be received already
+		 * \return  wether a message could be received already
 		 */
-		bool can_await_request() const;
-		void await_request();
+		void wait();
 
 		/**
-		 * Reply to last request if there's any
+		 * Reply to last message if there's any
 		 */
-		void send_reply();
+		void reply();
 
 		/**
-		 * If IPC node waits, cancel '_outbuf' to stop waiting
+		 * If IPC node waits, cancel it
 		 */
 		void cancel_waiting();
 
-		bool awaits_request() const { return _in.waiting(); }
+		/**
+		 * Return whether this IPC node is waiting for messages
+		 */
+		bool waiting() const { return _in.waiting(); }
 };
 
 #endif /* _CORE__KERNEL__IPC_NODE_H_ */

repos/base-hw/src/core/kernel/thread.cc

@@ -295,8 +295,8 @@ void Thread::_become_inactive(State const s)
 void Thread::_die() { _become_inactive(DEAD); }
 
 
-Cpu_job * Thread::helping_sink() {
-	return &_ipc_node.helping_sink(); }
+Cpu_job * Thread::helping_destination() {
+	return &_ipc_node.helping_destination(); }
 
 
 size_t Thread::_core_to_kernel_quota(size_t const quota) const
@@ -478,16 +478,16 @@ void Thread::_call_delete_pd()
 
 void Thread::_call_await_request_msg()
 {
-	if (_ipc_node.can_await_request()) {
+	if (_ipc_node.ready_to_wait()) {
 		_ipc_alloc_recv_caps((unsigned)user_arg_1());
-		_ipc_node.await_request();
-		if (_ipc_node.awaits_request()) {
+		_ipc_node.wait();
+		if (_ipc_node.waiting()) {
 			_become_inactive(AWAITS_IPC);
 		} else {
 			user_arg_0(0);
 		}
 	} else {
-		Genode::raw("IPC await request: bad state");
+		Genode::raw("IPC await request: bad state, will block");
 		_become_inactive(DEAD);
 	}
 }
@@ -539,12 +539,12 @@ void Thread::_call_send_request_msg()
 	bool const help = Cpu_job::_helping_possible(*dst);
 	oir = oir->find(dst->pd());
 
-	if (!_ipc_node.can_send_request()) {
+	if (!_ipc_node.ready_to_send()) {
 		Genode::raw("IPC send request: bad state");
 	} else {
 		_ipc_alloc_recv_caps((unsigned)user_arg_2());
 		_ipc_capid    = oir ? oir->capid() : cap_id_invalid();
-		_ipc_node.send_request(dst->_ipc_node, help);
+		_ipc_node.send(dst->_ipc_node, help);
 	}
 
 	_state = AWAITS_IPC;
@@ -554,7 +554,7 @@ void Thread::_call_send_request_msg()
 
 void Thread::_call_send_reply_msg()
 {
-	_ipc_node.send_reply();
+	_ipc_node.reply();
 	bool const await_request_msg = user_arg_2();
 	if (await_request_msg) { _call_await_request_msg(); }
 	else { user_arg_0(0); }

repos/base-hw/src/core/kernel/thread.h

@@ -418,9 +418,9 @@ class Kernel::Thread : private Kernel::Object, public Cpu_job, private Timeout
 		 ** Cpu_job **
 		 *************/
 
-		void exception(Cpu & cpu) override;
-		void proceed(Cpu & cpu)   override;
-		Cpu_job * helping_sink()  override;
+		void exception(Cpu & cpu)       override;
+		void proceed(Cpu & cpu)         override;
+		Cpu_job * helping_destination() override;
 
 
 		/*************

repos/base-hw/src/core/kernel/vm.h

@@ -142,9 +142,9 @@ class Kernel::Vm : private Kernel::Object, public Cpu_job
 		 ** Cpu_job **
 		 *************/
 
-		void exception(Cpu & cpu) override;
-		void proceed(Cpu &  cpu)  override;
-		Cpu_job * helping_sink()  override { return this; }
+		void exception(Cpu & cpu)       override;
+		void proceed(Cpu &  cpu)        override;
+		Cpu_job * helping_destination() override { return this; }
 };
 
 #endif /* _CORE__KERNEL__VM_H_ */