*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/client/Client.cxx

@@ -28,7 +28,7 @@ const Domain client_domain("client");
 #ifdef ENABLE_DATABASE
 
 const Database *
-Client::GetDatabase() const
+Client::GetDatabase() const noexcept
 {
 	return partition.instance.GetDatabase();
 }
@@ -40,7 +40,7 @@ Client::GetDatabaseOrThrow() const
 }
 
 const Storage *
-Client::GetStorage() const
+Client::GetStorage() const noexcept
 {
 	return partition.instance.storage;
 }

src/client/Client.hxx

@@ -160,7 +160,7 @@ public:
 	};
 
 	gcc_pure
-	bool IsSubscribed(const char *channel_name) const {
+	bool IsSubscribed(const char *channel_name) const noexcept {
 		return subscriptions.find(channel_name) != subscriptions.end();
 	}
 
@@ -186,7 +186,7 @@ public:
 	 * Wrapper for Instance::GetDatabase().
 	 */
 	gcc_pure
-	const Database *GetDatabase() const;
+	const Database *GetDatabase() const noexcept;
 
 	/**
 	 * Wrapper for Instance::GetDatabaseOrThrow().
@@ -195,7 +195,7 @@ public:
 	const Database &GetDatabaseOrThrow() const;
 
 	gcc_pure
-	const Storage *GetStorage() const;
+	const Storage *GetStorage() const noexcept;
 
 private:
 	/* virtual methods from class BufferedSocket */

src/client/ClientMessage.cxx

@@ -23,14 +23,14 @@
 
 gcc_const
 static bool
-valid_channel_char(const char ch)
+valid_channel_char(const char ch) noexcept
 {
 	return IsAlphaNumericASCII(ch) ||
 		ch == '_' || ch == '-' || ch == '.' || ch == ':';
 }
 
 bool
-client_message_valid_channel_name(const char *name)
+client_message_valid_channel_name(const char *name) noexcept
 {
 	do {
 		if (!valid_channel_char(*name))

src/client/ClientMessage.hxx

@@ -53,6 +53,6 @@ public:
 
 gcc_pure
 bool
-client_message_valid_channel_name(const char *name);
+client_message_valid_channel_name(const char *name) noexcept;
 
 #endif