input/async: eliminate attribute "postponed_error"

src/input/AsyncInputStream.cxx

@@ -24,6 +24,8 @@
 #include "thread/Cond.hxx"
 #include "IOThread.hxx"
 
+#include <stdexcept>
+
 #include <assert.h>
 #include <string.h>
 
@@ -64,16 +66,6 @@ AsyncInputStream::Pause()
 	paused = true;
 }
 
-void
-AsyncInputStream::PostponeError(Error &&error)
-{
-	assert(io_thread_inside());
-
-	seek_state = SeekState::NONE;
-	postponed_error = std::move(error);
-	cond.broadcast();
-}
-
 inline void
 AsyncInputStream::Resume()
 {
@@ -87,7 +79,7 @@ AsyncInputStream::Resume()
 }
 
 bool
-AsyncInputStream::Check(Error &error)
+AsyncInputStream::Check(Error &)
 {
 	if (postponed_exception) {
 		auto e = std::move(postponed_exception);
@@ -95,13 +87,7 @@ AsyncInputStream::Check(Error &error)
 		std::rethrow_exception(e);
 	}
 
-	bool success = !postponed_error.IsDefined();
-	if (!success) {
-		error = std::move(postponed_error);
-		postponed_error.Clear();
-	}
-
-	return success;
+	return true;
 }
 
 bool
@@ -121,10 +107,8 @@ AsyncInputStream::Seek(offset_type new_offset, Error &error)
 		/* no-op */
 		return true;
 
-	if (!IsSeekable()) {
-		error.Set(input_domain, "Not seekable");
-		return false;
-	}
+	if (!IsSeekable())
+		throw std::runtime_error("Not seekable");
 
 	/* check if we can fast-forward the buffer */
 
@@ -187,8 +171,7 @@ AsyncInputStream::ReadTag()
 bool
 AsyncInputStream::IsAvailable()
 {
-	return postponed_error.IsDefined() ||
-		postponed_exception ||
+	return postponed_exception ||
 		IsEOF() ||
 		!buffer.IsEmpty();
 }
@@ -289,6 +272,7 @@ AsyncInputStream::DeferredSeek()
 
 		DoSeek(seek_offset);
 	} catch (...) {
+		seek_state = SeekState::NONE;
 		postponed_exception = std::current_exception();
 		cond.broadcast();
 	}

src/input/AsyncInputStream.hxx

@@ -24,7 +24,6 @@
 #include "event/DeferredCall.hxx"
 #include "util/HugeAllocator.hxx"
 #include "util/CircularBuffer.hxx"
-#include "util/Error.hxx"
 
 #include <exception>
 
@@ -67,8 +66,6 @@ class AsyncInputStream : public InputStream {
 	offset_type seek_offset;
 
 protected:
-	Error postponed_error;
-
 	std::exception_ptr postponed_exception;
 
 public:
@@ -116,11 +113,6 @@ protected:
 		open = false;
 	}
 
-	/**
-	 * Pass an error from the I/O thread to the client thread.
-	 */
-	void PostponeError(Error &&error);
-
 	bool IsBufferEmpty() const {
 		return buffer.IsEmpty();
 	}