base: move common exception types to exception.h

The univerally used exception types Out_of_ram, Out_of_caps, and Denied
used to be defined at quota_guard.h and ram_allocator.h whereas the
types are broadly used. This patch gathers those type definitions at
the central place exception.h instead, to gradually untangle the reliance
on exceptions, i.e., in quota_goard.h, and to make the output of error
messages printing exception types ('abort') more concise.

Issue #5245

repos/base/include/base/allocator.h

@@ -60,16 +60,13 @@ struct Genode::Deallocator : Interface
 
 struct Genode::Allocator : Deallocator
 {
-	/**
-	 * Exception type
-	 */
 	using Out_of_memory = Out_of_ram;
-	using Denied        = Ram_allocator::Denied;
+	using Denied        = Genode::Denied;
 
 	/**
 	 * Return type of 'try_alloc'
 	 */
-	using Alloc_error  = Ram_allocator::Alloc_error;
+	using Alloc_error  = Genode::Alloc_error;
 	using Alloc_result = Attempt<void *, Alloc_error>;
 
 	/**

repos/base/include/base/exception.h

@@ -1,11 +1,11 @@
 /*
- * \brief  Exception base class
+ * \brief  Common exception types
  * \author Norman Feske
  * \date   2008-03-22
  */
 
 /*
- * Copyright (C) 2008-2017 Genode Labs GmbH
+ * Copyright (C) 2008-2025 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU Affero General Public License version 3.
@@ -14,8 +14,12 @@
 #ifndef _INCLUDE__BASE__EXCEPTION_H_
 #define _INCLUDE__BASE__EXCEPTION_H_
 
-namespace Genode { class Exception; }
+namespace Genode {
 
-class Genode::Exception { };
+	struct Exception { };
+	struct Out_of_ram  : Exception { };
+	struct Out_of_caps : Exception { };
+	struct Denied      : Exception { };
+}
 
 #endif /* _INCLUDE__BASE__EXCEPTION_H_ */

repos/base/include/base/quota_guard.h

@@ -22,6 +22,8 @@ namespace Genode {
 
 	struct Ram_quota
 	{
+		using Exhausted_exception = Out_of_ram;
+
 		size_t value;
 
 		static char const *name() { return "bytes"; }
@@ -31,6 +33,8 @@ namespace Genode {
 
 	struct Cap_quota
 	{
+		using Exhausted_exception = Out_of_caps;
+
 		size_t value;
 
 		static char const *name() { return "caps"; }
@@ -171,7 +175,7 @@ class Genode::Quota_guard
 
 	public:
 
-		struct Limit_exceeded : Exception { };
+		using Limit_exceeded = typename UNIT::Exhausted_exception;
 
 		Quota_guard() { }
 		Quota_guard(UNIT amount) { upgrade(amount); }
@@ -288,12 +292,8 @@ class Genode::Quota_guard
 
 
 namespace Genode {
-
 	using Ram_quota_guard = Quota_guard<Ram_quota>;
 	using Cap_quota_guard = Quota_guard<Cap_quota>;
-
-	using Out_of_ram = Ram_quota_guard::Limit_exceeded;
-	using Out_of_caps = Cap_quota_guard::Limit_exceeded;
 }
 
 #endif /* _INCLUDE__BASE__QUOTA_GUARD_H_ */

repos/base/include/base/ram_allocator.h

@@ -31,8 +31,6 @@ namespace Genode {
 
 struct Genode::Ram_allocator : Ram::Unmapped_allocator
 {
-	struct Denied : Exception { };
-
 	/**
 	 * Allocate RAM
 	 *
@@ -75,6 +73,7 @@ struct Genode::Ram_allocator : Ram::Unmapped_allocator
 	/* type aliases used for API transition */
 	using Alloc_result = Ram::Unmapped_allocator::Result;
 	using Alloc_error  = Ram::Error;
+	using Denied       = Genode::Denied;
 };
 
 
@@ -87,7 +86,7 @@ namespace Genode {
 		case Ram::Error::OUT_OF_CAPS: throw Out_of_caps();
 		case Ram::Error::DENIED:      break;
 		}
-		throw Ram_allocator::Denied();
+		throw Denied();
 	}
 }
 

repos/base/include/session/session.h

@@ -14,6 +14,7 @@
 #ifndef _INCLUDE__SESSION__SESSION_H_
 #define _INCLUDE__SESSION__SESSION_H_
 
+#include <base/exception.h>
 #include <base/quota_guard.h>
 #include <base/session_label.h>
 #include <util/arg_string.h>
@@ -34,7 +35,7 @@ namespace Genode {
 	 */
 	struct Insufficient_ram_quota : Exception { };
 	struct Insufficient_cap_quota : Exception { };
-	struct Service_denied         : Exception { };
+	using  Service_denied = Denied;
 }
 
 

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

@@ -27,6 +27,11 @@ namespace Core { template <typename> class Account; }
 template <typename UNIT>
 class Core::Account
 {
+	public:
+
+		using Limit_exceeded = UNIT::Exhausted_exception;
+		using Guard          = Quota_guard<UNIT>;
+
 	private:
 
 		/*
@@ -35,7 +40,7 @@ class Core::Account
 		Account(Account const &);
 		Account &operator = (Account const &);
 
-		Quota_guard<UNIT> &_quota_guard;
+		Guard &_quota_guard;
 
 		Session::Label const &_label;
 
@@ -88,16 +93,11 @@ class Core::Account
 
 	public:
 
-		using Limit_exceeded = typename Quota_guard<UNIT>::Limit_exceeded;
-
-		class Unrelated_account : Exception { };
-
 		/**
 		 * Constructor for creating a regular account that is rechargeable by
 		 * the specified reference account
 		 */
-		Account(Quota_guard<UNIT> &quota_guard, Session_label const &label,
+		Account(Guard &quota_guard, Session_label const &label, Account &ref_account)
-		        Account &ref_account)
 		:
 			_quota_guard(quota_guard), _label(label),
 			_initial_limit(_quota_guard.limit())
@@ -108,7 +108,7 @@ class Core::Account
 		/**
 		 * Constructor used for creating the initial account
 		 */
-		Account(Quota_guard<UNIT> &quota_guard, Session_label const &label)
+		Account(Guard &quota_guard, Session_label const &label)
 		: _quota_guard(quota_guard), _label(label), _initial_limit(UNIT{0}) { }
 
 		~Account()