From 1f3d3970f672ec9b200ed358e2d02c45c97c34eb Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Wed, 6 Aug 2014 17:20:03 +0200
Subject: db/update/InotifySource: remove FifoBuffer

Eliminate support for partial reads.  The Linux kernel will never
return partial results, so this buffering was unnecessary.
---
 src/db/update/InotifySource.cxx | 28 +++++++++++++++-------------
 src/db/update/InotifySource.hxx |  3 ---
 2 files changed, 15 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/db/update/InotifySource.cxx b/src/db/update/InotifySource.cxx
index c2783690e..233504ad6 100644
--- a/src/db/update/InotifySource.cxx
+++ b/src/db/update/InotifySource.cxx
@@ -25,43 +25,45 @@
 #include "system/FatalError.hxx"
 #include "Log.hxx"
 
+#include <algorithm>
+
 #include <sys/inotify.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdint.h>
+#include <limits.h>
 
 bool
 InotifySource::OnSocketReady(gcc_unused unsigned flags)
 {
-	const auto dest = buffer.Write();
-	if (dest.IsEmpty())
-		FatalError("buffer full");
+	uint8_t buffer[4096];
+	static_assert(sizeof(buffer) >= sizeof(struct inotify_event) + NAME_MAX + 1,
+		      "inotify buffer too small");
 
-	ssize_t nbytes = read(Get(), dest.data, dest.size);
+	ssize_t nbytes = read(Get(), buffer, sizeof(buffer));
 	if (nbytes < 0)
 		FatalSystemError("Failed to read from inotify");
 	if (nbytes == 0)
 		FatalError("end of file from inotify");
 
-	buffer.Append(nbytes);
+	const uint8_t *p = buffer, *const end = p + nbytes;
 
 	while (true) {
-		const char *name;
-
-		auto range = buffer.Read();
+		const size_t remaining = end - p;
 		const struct inotify_event *event =
-			(const struct inotify_event *)
-			range.data;
-		if (range.size < sizeof(*event) ||
-		    range.size < sizeof(*event) + event->len)
+			(const struct inotify_event *)p;
+		if (remaining < sizeof(*event) ||
+		    remaining < sizeof(*event) + event->len)
 			break;
 
+		const char *name;
 		if (event->len > 0 && event->name[event->len - 1] == 0)
 			name = event->name;
 		else
 			name = nullptr;
 
 		callback(event->wd, event->mask, name, callback_ctx);
-		buffer.Consume(sizeof(*event) + event->len);
+		p += sizeof(*event) + event->len;
 	}
 
 	return true;
diff --git a/src/db/update/InotifySource.hxx b/src/db/update/InotifySource.hxx
index 77c11093c..081ce10f3 100644
--- a/src/db/update/InotifySource.hxx
+++ b/src/db/update/InotifySource.hxx
@@ -21,7 +21,6 @@
 #define MPD_INOTIFY_SOURCE_HXX
 
 #include "event/SocketMonitor.hxx"
-#include "util/FifoBuffer.hxx"
 
 class Error;
 
@@ -32,8 +31,6 @@ class InotifySource final : private SocketMonitor {
 	mpd_inotify_callback_t callback;
 	void *callback_ctx;
 
-	FifoBuffer<uint8_t, 4096> buffer;
-
 	InotifySource(EventLoop &_loop,
 		      mpd_inotify_callback_t callback, void *ctx, int fd);
 
-- 
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