From 52bf08afc4b9da9ccdd73089c8ebfc7bda859bd3 Mon Sep 17 00:00:00 2001
From: Dan Engelbrecht <dan.engelbrecht@epicgames.com>
Date: Thu, 24 Mar 2022 22:41:46 +0100
Subject: Migration now works in larger disk IO chunks BasicFile and CasLogFile
 now has new explicit modes instead of create true/false

---
 zenstore/basicfile.cpp | 64 +++++++++++++++++++++++++++++++-------------------
 1 file changed, 40 insertions(+), 24 deletions(-)

(limited to 'zenstore/basicfile.cpp')

diff --git a/zenstore/basicfile.cpp b/zenstore/basicfile.cpp
index 77bada95f..fc7282941 100644
--- a/zenstore/basicfile.cpp
+++ b/zenstore/basicfile.cpp
@@ -29,10 +29,10 @@ BasicFile::~BasicFile()
 }
 
 void
-BasicFile::Open(const std::filesystem::path& FileName, bool IsCreate)
+BasicFile::Open(const std::filesystem::path& FileName, EMode Mode)
 {
 	std::error_code Ec;
-	Open(FileName, IsCreate, Ec);
+	Open(FileName, Mode, Ec);
 
 	if (Ec)
 	{
@@ -41,16 +41,20 @@ BasicFile::Open(const std::filesystem::path& FileName, bool IsCreate)
 }
 
 void
-BasicFile::Open(const std::filesystem::path& FileName, bool IsCreate, std::error_code& Ec)
+BasicFile::Open(const std::filesystem::path& FileName, EMode Mode, std::error_code& Ec)
 {
 	Ec.clear();
+	uint32_t ModeFlags = static_cast<uint32_t>(Mode);
 
 #if ZEN_PLATFORM_WINDOWS
-	const DWORD dwCreationDisposition = IsCreate ? CREATE_ALWAYS : OPEN_EXISTING;
-	DWORD		dwDesiredAccess		  = GENERIC_READ | GENERIC_WRITE | DELETE;
-	const DWORD dwShareMode			  = FILE_SHARE_READ;
-	const DWORD dwFlagsAndAttributes  = FILE_ATTRIBUTE_NORMAL;
-	HANDLE		hTemplateFile		  = nullptr;
+	const DWORD dwCreationDisposition = (ModeFlags & static_cast<uint32_t>(kAccessTruncate)) ? CREATE_ALWAYS : OPEN_EXISTING;
+	DWORD		dwDesiredAccess		  = GENERIC_READ;
+	dwDesiredAccess |= (ModeFlags & static_cast<uint32_t>(kAccessWrite)) ? GENERIC_WRITE : 0;
+	dwDesiredAccess |= (ModeFlags & static_cast<uint32_t>(kAccessDelete)) ? DELETE : 0;
+
+	const DWORD dwShareMode			 = FILE_SHARE_READ;
+	const DWORD dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
+	HANDLE		hTemplateFile		 = nullptr;
 
 	HANDLE FileHandle = CreateFile(FileName.c_str(),
 								   dwDesiredAccess,
@@ -67,8 +71,9 @@ BasicFile::Open(const std::filesystem::path& FileName, bool IsCreate, std::error
 		return;
 	}
 #else
-	int OpenFlags = O_RDWR | O_CLOEXEC;
-	OpenFlags |= IsCreate ? O_CREAT | O_TRUNC : 0;
+	int OpenFlags = O_CLOEXEC;
+	OpenFlags |= (ModeFlags & static_cast<uint32_t>(kAccessWrite)) ? O_RDWR : 0;
+	OpenFlags |= (ModeFlags & static_cast<uint32_t>(kAccessTruncate)) ? (O_CREAT | O_TRUNC) : 0;
 
 	int Fd = open(FileName.c_str(), OpenFlags, 0666);
 	if (Fd < 0)
@@ -105,27 +110,33 @@ BasicFile::Close()
 void
 BasicFile::Read(void* Data, uint64_t BytesToRead, uint64_t FileOffset)
 {
-	const uint64_t MaxChunkSize = 2u * 1024 * 1024 * 1024;
+	const uint64_t MaxChunkSize	 = 2u * 1024 * 1024 * 1024;
+	uint64_t	   TotalFileSize = FileSize();
+	ZEN_ASSERT((FileOffset + BytesToRead) <= TotalFileSize);
 
 	while (BytesToRead)
 	{
 		const uint64_t NumberOfBytesToRead = Min(BytesToRead, MaxChunkSize);
+		uint64_t	   NumberOfBytesRead;
 
 #if ZEN_PLATFORM_WINDOWS
 		OVERLAPPED Ovl{};
 
 		Ovl.Offset	   = DWORD(FileOffset & 0xffff'ffffu);
 		Ovl.OffsetHigh = DWORD(FileOffset >> 32);
+		ZEN_ASSERT((FileOffset + NumberOfBytesToRead) <= TotalFileSize);
 
 		DWORD dwNumberOfBytesRead = 0;
 		BOOL  Success			  = ::ReadFile(m_FileHandle, Data, DWORD(NumberOfBytesToRead), &dwNumberOfBytesRead, &Ovl);
 
-		ZEN_ASSERT(dwNumberOfBytesRead == NumberOfBytesToRead);
+		ZEN_ASSERT((dwNumberOfBytesRead <= NumberOfBytesToRead) && (dwNumberOfBytesRead > 0));
+		NumberOfBytesRead = dwNumberOfBytesRead;
 #else
 		static_assert(sizeof(off_t) >= sizeof(uint64_t), "sizeof(off_t) does not support large files");
-		int	 Fd		   = int(uintptr_t(m_FileHandle));
-		int	 BytesRead = pread(Fd, Data, NumberOfBytesToRead, FileOffset);
-		bool Success   = (BytesRead > 0);
+		int	 Fd			  = int(uintptr_t(m_FileHandle));
+		int	 BytesRead	  = pread(Fd, Data, NumberOfBytesToRead, FileOffset);
+		bool Success	  = (BytesRead > 0);
+		NumberOfBytesRead = static_cast<uint64_t>(BytesRead);
 #endif
 
 		if (!Success)
@@ -133,9 +144,9 @@ BasicFile::Read(void* Data, uint64_t BytesToRead, uint64_t FileOffset)
 			ThrowLastError(fmt::format("Failed to read from file '{}'", zen::PathFromHandle(m_FileHandle)));
 		}
 
-		BytesToRead -= NumberOfBytesToRead;
-		FileOffset += NumberOfBytesToRead;
-		Data = reinterpret_cast<uint8_t*>(Data) + NumberOfBytesToRead;
+		BytesToRead -= NumberOfBytesRead;
+		FileOffset += NumberOfBytesRead;
+		Data = reinterpret_cast<uint8_t*>(Data) + NumberOfBytesRead;
 	}
 }
 
@@ -263,7 +274,14 @@ BasicFile::FileSize()
 #if ZEN_PLATFORM_WINDOWS
 	ULARGE_INTEGER liFileSize;
 	liFileSize.LowPart = ::GetFileSize(m_FileHandle, &liFileSize.HighPart);
-
+	if (liFileSize.LowPart == INVALID_FILE_SIZE)
+	{
+		int Error = GetLastError();
+		if (Error)
+		{
+			ThrowSystemError(Error, fmt::format("Failed to get file size from file '{}'", zen::PathFromHandle(m_FileHandle)));
+		}
+	}
 	return uint64_t(liFileSize.QuadPart);
 #else
 	int Fd = int(uintptr_t(m_FileHandle));
@@ -351,9 +369,7 @@ TemporaryFile::CreateTemporary(std::filesystem::path TempDirName, std::error_cod
 
 	m_TempPath = TempDirName / TempName.c_str();
 
-	const bool IsCreate = true;
-
-	Open(m_TempPath, IsCreate, Ec);
+	Open(m_TempPath, BasicFile::EMode::kTruncateDelete, Ec);
 }
 
 void
@@ -453,8 +469,8 @@ TEST_CASE("BasicFile")
 	ScopedCurrentDirectoryChange _;
 
 	BasicFile File1;
-	CHECK_THROWS(File1.Open("zonk", false));
-	CHECK_NOTHROW(File1.Open("zonk", true));
+	CHECK_THROWS(File1.Open("zonk", BasicFile::EMode::kRead));
+	CHECK_NOTHROW(File1.Open("zonk", BasicFile::EMode::kTruncate));
 	CHECK_NOTHROW(File1.Write("abcd", 4, 0));
 	CHECK(File1.FileSize() == 4);
 	{
-- 
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