From cad35a83fb2a4ad2952888d258bd6ad32cff7c02 Mon Sep 17 00:00:00 2001
From: Max Kellermann <mk@cm4all.com>
Date: Wed, 27 Sep 2023 10:46:43 +0200
Subject: [PATCH] io/FileDescriptor: add Read()/Write() overloads with
 std::span

---
 src/event/InotifyEvent.cxx                 | 3 +--
 src/io/FileDescriptor.hxx                  | 8 ++++++++
 src/output/plugins/OssOutputPlugin.cxx     | 2 +-
 src/output/plugins/SolarisOutputPlugin.cxx | 2 +-
 src/system/EventFD.cxx                     | 2 +-
 test/run_convert.cxx                       | 2 +-
 test/run_output.cxx                        | 2 +-
 7 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/event/InotifyEvent.cxx b/src/event/InotifyEvent.cxx
index e5ce9abcd..643190159 100644
--- a/src/event/InotifyEvent.cxx
+++ b/src/event/InotifyEvent.cxx
@@ -64,8 +64,7 @@ try {
 	static_assert(sizeof(buffer) >= sizeof(struct inotify_event) + NAME_MAX + 1,
 		      "inotify buffer too small");
 
-	ssize_t nbytes = event.GetFileDescriptor().Read(buffer.data(),
-							buffer.size());
+	ssize_t nbytes = event.GetFileDescriptor().Read(buffer);
 	if (nbytes <= 0) [[unlikely]] {
 		if (nbytes == 0)
 			throw std::runtime_error{"EOF from inotify"};
diff --git a/src/io/FileDescriptor.hxx b/src/io/FileDescriptor.hxx
index 283566147..6da440a35 100644
--- a/src/io/FileDescriptor.hxx
+++ b/src/io/FileDescriptor.hxx
@@ -217,6 +217,10 @@ public:
 	}
 #endif
 
+	ssize_t Read(std::span<std::byte> dest) const noexcept {
+		return ::read(fd, dest.data(), dest.size());
+	}
+
 	ssize_t Read(void *buffer, std::size_t length) const noexcept {
 		return ::read(fd, buffer, length);
 	}
@@ -227,6 +231,10 @@ public:
 	 */
 	void FullRead(std::span<std::byte> dest) const;
 
+	ssize_t Write(std::span<const std::byte> src) const noexcept {
+		return ::write(fd, src.data(), src.size());
+	}
+
 	ssize_t Write(const void *buffer, std::size_t length) const noexcept {
 		return ::write(fd, buffer, length);
 	}
diff --git a/src/output/plugins/OssOutputPlugin.cxx b/src/output/plugins/OssOutputPlugin.cxx
index 40cb9a054..7b6a8f981 100644
--- a/src/output/plugins/OssOutputPlugin.cxx
+++ b/src/output/plugins/OssOutputPlugin.cxx
@@ -671,7 +671,7 @@ OssOutput::Play(std::span<const std::byte> src)
 		return src.size();
 
 	while (true) {
-		const ssize_t ret = fd.Write(e.data(), e.size());
+		const ssize_t ret = fd.Write(e);
 		if (ret > 0)
 			return pcm_export->CalcInputSize(ret);
 
diff --git a/src/output/plugins/SolarisOutputPlugin.cxx b/src/output/plugins/SolarisOutputPlugin.cxx
index d77533076..5572b18d9 100644
--- a/src/output/plugins/SolarisOutputPlugin.cxx
+++ b/src/output/plugins/SolarisOutputPlugin.cxx
@@ -125,7 +125,7 @@ SolarisOutput::Close() noexcept
 std::size_t
 SolarisOutput::Play(std::span<const std::byte> src)
 {
-	ssize_t nbytes = fd.Write(src.data(), src.size());
+	ssize_t nbytes = fd.Write(src);
 	if (nbytes <= 0)
 		throw MakeErrno("Write failed");
 
diff --git a/src/system/EventFD.cxx b/src/system/EventFD.cxx
index d0916d4ab..b3a740165 100644
--- a/src/system/EventFD.cxx
+++ b/src/system/EventFD.cxx
@@ -21,7 +21,7 @@ EventFD::Read() noexcept
 	assert(fd.IsDefined());
 
 	eventfd_t value;
-	return fd.Read(&value, sizeof(value)) == (ssize_t)sizeof(value);
+	return fd.Read(std::as_writable_bytes(std::span{&value, 1})) == (ssize_t)sizeof(value);
 }
 
 void
diff --git a/test/run_convert.cxx b/test/run_convert.cxx
index 75c9e58ab..fd6355c2b 100644
--- a/test/run_convert.cxx
+++ b/test/run_convert.cxx
@@ -99,7 +99,7 @@ RunConvert(PcmConvert &convert, size_t in_frame_size,
 			const auto dest = buffer.Write();
 			assert(!dest.empty());
 
-			ssize_t nbytes = in_fd.Read(dest.data(), dest.size());
+			ssize_t nbytes = in_fd.Read(dest);
 			if (nbytes <= 0)
 				break;
 
diff --git a/test/run_output.cxx b/test/run_output.cxx
index dad7c34e3..4a918f811 100644
--- a/test/run_output.cxx
+++ b/test/run_output.cxx
@@ -124,7 +124,7 @@ RunOutput(AudioOutput &ao, AudioFormat audio_format,
 			const auto dest = buffer.Write();
 			assert(!dest.empty());
 
-			ssize_t nbytes = in_fd.Read(dest.data(), dest.size());
+			ssize_t nbytes = in_fd.Read(dest);
 			if (nbytes <= 0)
 				break;