Remove exceptions from Rm_session interface

Issue #5245

repos/base-linux/src/include/base/internal/local_rm_session.h

@@ -38,10 +38,14 @@ struct Genode::Local_rm_session : Rm_session, Local_session
 		_local_rm(local_rm), _md_alloc(md_alloc)
 	{ }
 
-	Capability<Region_map> create(size_t size) override
+	Create_result create(size_t size) override
 	{
-		Region_map *rm = new (_md_alloc) Region_map_mmap(true, size);
-		return Local_capability<Region_map>::local_cap(rm);
+		try {
+			Region_map *rm = new (_md_alloc) Region_map_mmap(true, size);
+			return Local_capability<Region_map>::local_cap(rm);
+		}
+		catch (Out_of_ram)  { return Create_error::OUT_OF_RAM; }
+		catch (Out_of_caps) { return Create_error::OUT_OF_CAPS; }
 	}
 
 	void destroy(Capability<Region_map> cap) override

repos/base-linux/src/lib/base/rm_session_client.cc

@@ -35,7 +35,7 @@ Rm_session_client::Rm_session_client(Capability<Rm_session> session)
 : Rpc_client<Rm_session>(session) { }
 
 
-Capability<Region_map> Rm_session_client::create(size_t size) {
+Rm_session::Create_result Rm_session_client::create(size_t size) {
 	return _local(rpc_cap())->create(size); }
 
 

repos/base/include/region_map/region_map.h

@@ -14,6 +14,7 @@
 #ifndef _INCLUDE__REGION_MAP__REGION_MAP_H_
 #define _INCLUDE__REGION_MAP__REGION_MAP_H_
 
+#include <util/attempt.h>
 #include <base/exception.h>
 #include <base/stdint.h>
 #include <base/signal.h>

repos/base/include/rm_session/client.h

@@ -24,7 +24,7 @@ struct Genode::Rm_session_client : Rpc_client<Rm_session>
 {
 	explicit Rm_session_client(Rm_session_capability);
 
-	Capability<Region_map> create(size_t) override;
+	Create_result create(size_t) override;
 	void destroy(Capability<Region_map>) override;
 };
 

repos/base/include/rm_session/connection.h

@@ -21,31 +21,35 @@
 namespace Genode { struct Rm_connection; }
 
 
-struct Genode::Rm_connection : Connection<Rm_session>, Rm_session_client
+struct Genode::Rm_connection : Connection<Rm_session>
 {
+	Rm_session_client _client { cap() };
+
 	Rm_connection(Env &env)
 	:
-		Connection<Rm_session>(env, Label(), Ram_quota { 64*1024 }, Args()),
-		Rm_session_client(cap())
+		Connection<Rm_session>(env, {}, Ram_quota { 64*1024 }, Args())
 	{ }
 
 	/**
-	 * Wrapper over 'create' that handles resource requests from the server
+	 * Wrapper of 'create' that handles session-quota upgrades on demand
 	 */
-	Capability<Region_map> create(size_t size) override
+	Capability<Region_map> create(size_t size)
 	{
-		enum { UPGRADE_ATTEMPTS = 16U };
-
-		return Genode::retry<Out_of_ram>(
-			[&] () {
-				return Genode::retry<Out_of_caps>(
-					[&] () { return Rm_session_client::create(size); },
-					[&] () { upgrade_caps(2); },
-					UPGRADE_ATTEMPTS);
-			},
-			[&] () { upgrade_ram(8*1024); },
-			UPGRADE_ATTEMPTS);
+		Capability<Region_map> result { };
+		using Error = Rm_session::Create_error;
+		while (!result.valid())
+			_client.create(size).with_result(
+				[&] (Capability<Region_map> cap) { result = cap; },
+				[&] (Error e) {
+					switch (e) {
+					case Error::OUT_OF_RAM:  upgrade_ram(8*1024); break;
+					case Error::OUT_OF_CAPS: upgrade_caps(2);     break;
+					}
+				});
+		return result;
 	}
+
+	void destroy(Capability<Region_map> cap) { _client.destroy(cap); }
 };
 
 #endif /* _INCLUDE__RM_SESSION__CONNECTION_H_ */

repos/base/include/rm_session/rm_session.h

@@ -33,15 +33,16 @@ struct Genode::Rm_session : Session
 	 */
 	enum { CAP_QUOTA = 2 };
 
+	enum class Create_error { OUT_OF_RAM, OUT_OF_CAPS };
+	using Create_result = Attempt<Capability<Region_map>, Create_error>;
+
 	/**
 	 * Create region map
 	 *
 	 * \param size  upper bound of region map
 	 * \return      region-map capability
-	 * \throw       Out_of_ram
-	 * \throw       Out_of_caps
 	 */
-	virtual Capability<Region_map> create(size_t size) = 0;
+	virtual Create_result create(size_t size) = 0;
 
 	/**
 	 * Destroy region map
@@ -53,8 +54,7 @@ struct Genode::Rm_session : Session
 	 ** RPC declaration **
 	 *********************/
 
-	GENODE_RPC_THROW(Rpc_create, Capability<Region_map>, create,
-	                 GENODE_TYPE_LIST(Out_of_ram, Out_of_caps), size_t);
+	GENODE_RPC(Rpc_create, Create_result, create, size_t);
 	GENODE_RPC(Rpc_destroy, void, destroy, Capability<Region_map>);
 
 	GENODE_RPC_INTERFACE(Rpc_create, Rpc_destroy);

repos/base/src/core/include/rm_session_component.h

@@ -72,7 +72,7 @@ class Core::Rm_session_component : public Session_object<Rm_session>
 		 ** Rm_session interface **
 		 **************************/
 
-		Capability<Region_map> create(size_t size) override
+		Create_result create(size_t size) override
 		{
 			Mutex::Guard guard(_region_maps_lock);
 
@@ -86,7 +86,8 @@ class Core::Rm_session_component : public Session_object<Rm_session>
 
 				return rm->cap();
 			}
-			catch (Allocator::Out_of_memory) { throw Out_of_ram(); }
+			catch (Out_of_ram)  { return Create_error::OUT_OF_RAM; }
+			catch (Out_of_caps) { return Create_error::OUT_OF_CAPS; }
 		}
 
 		void destroy(Capability<Region_map> cap) override

repos/base/src/lib/base/rm_session_client.cc

@@ -20,7 +20,7 @@ Rm_session_client::Rm_session_client(Capability<Rm_session> cap)
 : Rpc_client<Rm_session>(cap) { }
 
 
-Capability<Region_map> Rm_session_client::create(size_t size) {
+Rm_session::Create_result Rm_session_client::create(size_t size) {
 	return call<Rpc_create>(size); }