From c2dd6808e1880447f00b95162483bcd34fe22c44 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Fri, 17 May 2019 10:55:58 +0200
Subject: [PATCH] input/buffering: make read errors fatal, no recovery

If a read error occurs, it is very unlikely that the InputStream will
ever recover.  Removing the code removes some code complexity which
just isn't worth it.  And it allows supporting multiple readers for
one buffer.
---
 src/input/BufferingInputStream.cxx | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/input/BufferingInputStream.cxx b/src/input/BufferingInputStream.cxx
index ebfffd943..9542e48b2 100644
--- a/src/input/BufferingInputStream.cxx
+++ b/src/input/BufferingInputStream.cxx
@@ -111,10 +111,8 @@ BufferingInputStream::Read(std::unique_lock<Mutex> &lock, void *ptr, size_t s)
 			return nbytes;
 		}
 
-		if (read_error) {
-			wake_cond.notify_one();
-			std::rethrow_exception(std::exchange(read_error, {}));
-		}
+		if (read_error)
+			std::rethrow_exception(read_error);
 
 		client_cond.wait(lock);
 	}
@@ -152,11 +150,7 @@ BufferingInputStream::RunThread() noexcept
 			}
 
 			seek = false;
-			read_error = {};
 			client_cond.notify_one();
-		} else if (read_error) {
-			/* wait for client to consume the read error */
-			wake_cond.wait(lock);
 		} else if (offset != input->GetOffset() && !IsAvailable()) {
 			/* a past Seek() call was a no-op because data
 			   was already available at that position, but
@@ -180,6 +174,7 @@ BufferingInputStream::RunThread() noexcept
 				read_error = std::current_exception();
 				client_cond.notify_one();
 				OnBufferAvailable();
+				break;
 			}
 		} else if (input->IsEOF()) {
 			/* our input has reached its end: prepare
@@ -198,6 +193,7 @@ BufferingInputStream::RunThread() noexcept
 				read_error = std::current_exception();
 				client_cond.notify_one();
 				OnBufferAvailable();
+				break;
 			}
 		} else if (input->IsAvailable()) {
 			const auto read_offset = input->GetOffset();
@@ -221,6 +217,7 @@ BufferingInputStream::RunThread() noexcept
 						read_error = std::current_exception();
 						client_cond.notify_one();
 						OnBufferAvailable();
+						break;
 					}
 				} else {
 					/* we need more data at our
@@ -235,6 +232,7 @@ BufferingInputStream::RunThread() noexcept
 						read_error = std::current_exception();
 						client_cond.notify_one();
 						OnBufferAvailable();
+						break;
 					}
 				}
 
@@ -248,6 +246,9 @@ BufferingInputStream::RunThread() noexcept
 					      read_offset + nbytes);
 			} catch (...) {
 				read_error = std::current_exception();
+				client_cond.notify_one();
+				OnBufferAvailable();
+				break;
 			}
 
 			client_cond.notify_one();