db/simple: migrate Mount() from class Error to C++ exceptions

src/command/StorageCommands.cxx

@@ -24,7 +24,6 @@
 #include "Request.hxx"
 #include "CommandError.hxx"
 #include "util/UriUtil.hxx"
-#include "util/Error.hxx"
 #include "util/ConstBuffer.hxx"
 #include "fs/Traits.hxx"
 #include "client/Client.hxx"
@@ -211,11 +210,7 @@ handle_mount(Client &client, Request args, Response &r)
 		SimpleDatabase &db = *(SimpleDatabase *)_db;
 
 		try {
-			Error error;
-			if (!db.Mount(local_uri, remote_uri, error)) {
-				composite.Unmount(local_uri);
-				return print_error(r, error);
-			}
+			db.Mount(local_uri, remote_uri);
 		} catch (...) {
 			composite.Unmount(local_uri);
 			throw;

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -395,9 +395,8 @@ IsUnsafeChar(char ch)
 	return !IsSafeChar(ch);
 }
 
-bool
-SimpleDatabase::Mount(const char *local_uri, const char *storage_uri,
-		      Error &error)
+void
+SimpleDatabase::Mount(const char *local_uri, const char *storage_uri)
 {
 	if (cache_path.IsNull())
 		throw DatabaseError(DatabaseErrorCode::NOT_FOUND,
@@ -406,9 +405,7 @@ SimpleDatabase::Mount(const char *local_uri, const char *storage_uri,
 	std::string name(storage_uri);
 	std::replace_if(name.begin(), name.end(), IsUnsafeChar, '_');
 
-	const auto name_fs = AllocatedPath::FromUTF8(name.c_str(), error);
-	if (name_fs.IsNull())
-		return false;
+	const auto name_fs = AllocatedPath::FromUTF8Throw(name.c_str());
 
 #ifndef ENABLE_ZLIB
 	constexpr bool compress = false;
@@ -432,8 +429,6 @@ SimpleDatabase::Mount(const char *local_uri, const char *storage_uri,
 		delete db;
 		throw;
 	}
-
-	return true;
 }
 
 Database *

src/db/plugins/simple/SimpleDatabasePlugin.hxx

@@ -98,9 +98,11 @@ public:
 	gcc_nonnull_all
 	void Mount(const char *uri, Database *db);
 
+	/**
+	 * Throws #std::runtime_error on error.
+	 */
 	gcc_nonnull_all
-	bool Mount(const char *local_uri, const char *storage_uri,
-		   Error &error);
+	void Mount(const char *local_uri, const char *storage_uri);
 
 	gcc_nonnull_all
 	bool Unmount(const char *uri);