From 800305f7f2afe01e9ca038a71a68e9318c52ee77 Mon Sep 17 00:00:00 2001
From: Dan Engelbrecht <dan.engelbrecht@epicgames.com>
Date: Wed, 12 Feb 2025 09:05:07 +0100
Subject: move WriteToTempFile to basicfile.h (#283)

add helper constructors to BasicFile
---
 src/zencore/basicfile.cpp | 64 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 2 deletions(-)

(limited to 'src/zencore/basicfile.cpp')

diff --git a/src/zencore/basicfile.cpp b/src/zencore/basicfile.cpp
index c2a21ae90..b3bffd34d 100644
--- a/src/zencore/basicfile.cpp
+++ b/src/zencore/basicfile.cpp
@@ -28,6 +28,20 @@ BasicFile::~BasicFile()
 {
 	Close();
 }
+BasicFile::BasicFile(const std::filesystem::path& FileName, Mode Mode)
+{
+	Open(FileName, Mode);
+}
+
+BasicFile::BasicFile(const std::filesystem::path& FileName, Mode Mode, std::error_code& Ec)
+{
+	Open(FileName, Mode, Ec);
+}
+
+BasicFile::BasicFile(const std::filesystem::path& FileName, Mode Mode, std::function<bool(std::error_code& Ec)>&& RetryCallback)
+{
+	Open(FileName, Mode, std::move(RetryCallback));
+}
 
 void
 BasicFile::Open(const std::filesystem::path& FileName, Mode Mode)
@@ -267,7 +281,7 @@ BasicFile::StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<voi
 }
 
 uint64_t
-BasicFile::Write(CompositeBuffer Data, uint64_t FileOffset, std::error_code& Ec)
+BasicFile::Write(const CompositeBuffer& Data, uint64_t FileOffset, std::error_code& Ec)
 {
 	uint64_t WrittenBytes = 0;
 	for (const SharedBuffer& Buffer : Data.GetSegments())
@@ -575,7 +589,6 @@ TemporaryFile::MoveTemporaryIntoPlace(std::filesystem::path FinalFileName, std::
 void
 TemporaryFile::SafeWriteFile(const std::filesystem::path& Path, MemoryView Data)
 {
-	TemporaryFile	TempFile;
 	std::error_code Ec;
 	SafeWriteFile(Path, Data, Ec);
 	if (Ec)
@@ -817,6 +830,53 @@ BasicFileWriter::Flush()
 	m_Base.Write(m_Buffer, BufferedBytes, WriteOffset);
 }
 
+IoBuffer
+WriteToTempFile(CompositeBuffer&& Buffer, const std::filesystem::path& Path, std::function<bool(std::error_code& Ec)>&& RetryCallback)
+{
+	if (std::filesystem::is_regular_file(Path))
+	{
+		IoBuffer ExistingTempFile = IoBuffer(IoBufferBuilder::MakeFromFile(Path));
+		if (ExistingTempFile && ExistingTempFile.GetSize() == Buffer.GetSize())
+		{
+			ExistingTempFile.SetDeleteOnClose(true);
+			return ExistingTempFile;
+		}
+	}
+	BasicFile BlockFile;
+	BlockFile.Open(Path, BasicFile::Mode::kTruncateDelete, std::move(RetryCallback));
+	uint64_t Offset = 0;
+	{
+		static const uint64_t BufferingSize = 256u * 1024u;
+		BasicFileWriter		  BufferedOutput(BlockFile, BufferingSize / 2);
+		for (const SharedBuffer& Segment : Buffer.GetSegments())
+		{
+			size_t SegmentSize = Segment.GetSize();
+
+			IoBufferFileReference FileRef;
+			if (SegmentSize >= (BufferingSize + BufferingSize / 2) && Segment.GetFileReference(FileRef))
+			{
+				ScanFile(FileRef.FileHandle,
+						 FileRef.FileChunkOffset,
+						 FileRef.FileChunkSize,
+						 BufferingSize,
+						 [&BufferedOutput, &Offset](const void* Data, size_t Size) {
+							 BufferedOutput.Write(Data, Size, Offset);
+							 Offset += Size;
+						 });
+			}
+			else
+			{
+				BufferedOutput.Write(Segment.GetData(), SegmentSize, Offset);
+				Offset += SegmentSize;
+			}
+		}
+	}
+	void*	 FileHandle	 = BlockFile.Detach();
+	IoBuffer BlockBuffer = IoBuffer(IoBuffer::File, FileHandle, 0, Offset, /*IsWholeFile*/ true);
+	BlockBuffer.SetDeleteOnClose(true);
+	return BlockBuffer;
+}
+
 //////////////////////////////////////////////////////////////////////////
 
 /*
-- 
cgit v1.2.3