input/Plugin: migrate open() from class Error to C++ exceptions

src/input/plugins/FileInputPlugin.cxx

@@ -21,18 +21,15 @@
 #include "FileInputPlugin.hxx"
 #include "../InputStream.hxx"
 #include "../InputPlugin.hxx"
-#include "util/Error.hxx"
-#include "util/Domain.hxx"
 #include "fs/Path.hxx"
 #include "fs/FileInfo.hxx"
 #include "fs/io/FileReader.hxx"
 #include "system/FileDescriptor.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <sys/stat.h>
 #include <fcntl.h>
 
-static constexpr Domain file_domain("file");
-
 class FileInputStream final : public InputStream {
 	FileReader reader;
 
@@ -56,38 +53,31 @@ public:
 	bool Seek(offset_type offset, Error &error) override;
 };
 
-InputStream *
+InputStreamPtr
 OpenFileInputStream(Path path,
-		    Mutex &mutex, Cond &cond,
-		    Error &error)
-try {
+		    Mutex &mutex, Cond &cond)
+{
 	FileReader reader(path);
 
 	const FileInfo info = reader.GetFileInfo();
 
-	if (!info.IsRegular()) {
-		error.Format(file_domain, "Not a regular file: %s",
-			     path.c_str());
-		return nullptr;
-	}
+	if (!info.IsRegular())
+		throw FormatRuntimeError("Not a regular file: %s",
+					 path.c_str());
 
 #ifdef POSIX_FADV_SEQUENTIAL
 	posix_fadvise(reader.GetFD().Get(), (off_t)0, info.GetSize(),
 		      POSIX_FADV_SEQUENTIAL);
 #endif
 
-	return new FileInputStream(path.ToUTF8().c_str(),
-				   std::move(reader), info.GetSize(),
-				   mutex, cond);
-} catch (const std::exception &e) {
-	error.Set(std::current_exception());
-	return nullptr;
+	return InputStreamPtr(new FileInputStream(path.ToUTF8().c_str(),
+						  std::move(reader), info.GetSize(),
+						  mutex, cond));
 }
 
 static InputStream *
 input_file_open(gcc_unused const char *filename,
-		gcc_unused Mutex &mutex, gcc_unused Cond &cond,
-		gcc_unused Error &error)
+		gcc_unused Mutex &mutex, gcc_unused Cond &cond)
 {
 	/* dummy method; use OpenFileInputStream() instead */