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

src/lib/ffmpeg/Error.cxx

@@ -26,6 +26,14 @@ extern "C" {
 #include <libavutil/error.h>
 }
 
+std::runtime_error
+MakeFfmpegError(int errnum)
+{
+	char msg[256];
+	av_strerror(errnum, msg, sizeof(msg));
+	return std::runtime_error(msg);
+}
+
 void
 SetFfmpegError(Error &error, int errnum)
 {

src/lib/ffmpeg/Error.hxx

@@ -20,8 +20,13 @@
 #ifndef MPD_FFMPEG_ERROR_HXX
 #define MPD_FFMPEG_ERROR_HXX
 
+#include <stdexcept>
+
 class Error;
 
+std::runtime_error
+MakeFfmpegError(int errnum);
+
 void
 SetFfmpegError(Error &error, int errnum);
 

src/lib/nfs/FileReader.cxx

@@ -91,23 +91,19 @@ NfsFileReader::DeferClose()
 	BlockingCall(io_thread_get(), [this](){ Close(); });
 }
 
-bool
-NfsFileReader::Open(const char *uri, Error &error)
+void
+NfsFileReader::Open(const char *uri)
 {
 	assert(state == State::INITIAL);
 
-	if (!StringStartsWith(uri, "nfs://")) {
-		error.Set(nfs_domain, "Malformed nfs:// URI");
-		return false;
-	}
+	if (!StringStartsWith(uri, "nfs://"))
+		throw std::runtime_error("Malformed nfs:// URI");
 
 	uri += 6;
 
 	const char *slash = strchr(uri, '/');
-	if (slash == nullptr) {
-		error.Set(nfs_domain, "Malformed nfs:// URI");
-		return false;
-	}
+	if (slash == nullptr)
+		throw std::runtime_error("Malformed nfs:// URI");
 
 	server = std::string(uri, slash);
 
@@ -121,10 +117,8 @@ NfsFileReader::Open(const char *uri, Error &error)
 		path = new_path;
 	} else {
 		slash = strrchr(uri + 1, '/');
-		if (slash == nullptr || slash[1] == 0) {
-			error.Set(nfs_domain, "Malformed nfs:// URI");
-			return false;
-		}
+		if (slash == nullptr || slash[1] == 0)
+			throw std::runtime_error("Malformed nfs:// URI");
 
 		export_name = std::string(uri, slash);
 		path = slash;
@@ -132,7 +126,6 @@ NfsFileReader::Open(const char *uri, Error &error)
 
 	state = State::DEFER;
 	DeferredMonitor::Schedule();
-	return true;
 }
 
 bool

src/lib/nfs/FileReader.hxx

@@ -61,7 +61,11 @@ public:
 	void Close();
 	void DeferClose();
 
-	bool Open(const char *uri, Error &error);
+	/**
+	 * Throws std::runtime_error on error.
+	 */
+	void Open(const char *uri);
+
 	bool Read(uint64_t offset, size_t size, Error &error);
 	void CancelRead();