Replace ExtendResult with std::optional

Author: Artyom Ivanov

src/jrd/nbak.cpp

@@ -389,9 +389,9 @@ bool BackupManager::extendDatabase(thread_db* tdbb)
 	if (maxAllocPage >= maxPage)
 		return true;
 
-	const auto extensionResult = pgSpace->extend(tdbb, maxPage, true);
+	const auto allocatedPages = pgSpace->extend(tdbb, maxPage, true);
 	maxAllocPage = pgSpace->maxAlloc();
-	if (extensionResult.success && maxAllocPage > maxPage)
+	if (allocatedPages.has_value() && maxAllocPage > maxPage)
 		return true;
 
 	// Fast file extension not succeeded for some reason, try file extension via direct file writes.

src/jrd/pag.cpp

@@ -312,9 +312,9 @@ namespace
 		const ULONG usedPages = sequence * pageMgr.pagesPerPIP + pipUsed;
 
 		const bool allocateExactNumberOfPages = dbb->dbb_flags & DBB_no_reserve;
-		const auto extensionResult = pageSpace->extend(tdbb, usedPages + initPages, allocateExactNumberOfPages);
-		if (extensionResult.success)
-			initPages = extensionResult.pagesAllocated;
+		const auto allocatedPages = pageSpace->extend(tdbb, usedPages + initPages, allocateExactNumberOfPages);
+		if (allocatedPages.has_value())
+			initPages = allocatedPages.value();
 		else
 		{
 			// For some reason fast file extension failed, maybe it is not supported by filesystem, or
@@ -1938,7 +1938,7 @@ ULONG PageSpace::usedPages(const Database* dbb)
 	return pgSpace->usedPages();
 }
 
-PageSpace::ExtendResult PageSpace::extend(thread_db* tdbb, const ULONG pageNum, bool forceSize)
+std::optional<ULONG> PageSpace::extend(thread_db* tdbb, const ULONG pageNum, bool forceSize)
 {
 /**************************************
  *
@@ -1958,11 +1958,11 @@ PageSpace::ExtendResult PageSpace::extend(thread_db* tdbb, const ULONG pageNum,
 	fb_assert(dbb == tdbb->getDatabase());
 
 	if (!PIO_fast_extension_is_supported(*file))
-		return {.success = false};
+		return std::nullopt;
 
 	// First, check it with the cached `maxPageNumber` value.
 	if (pageNum < maxPageNumber || pageNum < maxAlloc())
-		return {.success = true, .pagesAllocated = maxPageNumber - pageNum};
+		return maxPageNumber - pageNum;
 
 	const ULONG MAX_EXTEND_BYTES = static_cast<ULONG>(dbb->dbb_config->getDatabaseGrowthIncrement());
 	if (MAX_EXTEND_BYTES < MIN_EXTEND_BYTES)
@@ -1989,12 +1989,12 @@ PageSpace::ExtendResult PageSpace::extend(thread_db* tdbb, const ULONG pageNum,
 		try
 		{
 			if (!PIO_extend(tdbb, file, extPages, dbb->dbb_page_size))
-				return {.success = false};
+				return std::nullopt;
 
 			// File was extended, reset cached value
 			maxPageNumber = 0;
 
-			return {.success = true, .pagesAllocated = extPages};
+			return extPages;
 		}
 		catch (const status_exception&)
 		{
@@ -2005,15 +2005,15 @@ PageSpace::ExtendResult PageSpace::extend(thread_db* tdbb, const ULONG pageNum,
 				// if file was extended, return, else try to extend by less pages
 
 				if (const auto newMaxPageNumber = maxAlloc(); oldMaxPageNumber < newMaxPageNumber)
-					return {.success = true, .pagesAllocated = newMaxPageNumber - oldMaxPageNumber};
+					return newMaxPageNumber - oldMaxPageNumber;
 
 				extPages = MAX(reqPages, extPages / 2);
 			}
 			else
 			{
 				gds__log("Error extending file \"%s\" by %lu page(s).\nCurrently allocated %lu pages, requested page number %lu",
 					file->fil_string, extPages, maxPageNumber, pageNum);
-				return {.success = false};
+				return std::nullopt;
 			}
 		}
 	}

src/jrd/pag.h

@@ -129,13 +129,8 @@ class PageSpace : public pool_alloc<type_PageSpace>
 	ULONG usedPages();
 	static ULONG usedPages(const Database* dbb);
 
-	struct ExtendResult
-	{
-		bool success = false;
-		ULONG pagesAllocated = 0;
-	};
 	// extend page space
-	ExtendResult extend(thread_db* tdbb, ULONG pageNum, bool forceSize);
+	std::optional<ULONG> extend(thread_db* tdbb, ULONG pageNum, bool forceSize);
 
 	// get SCN's page number
 	ULONG getSCNPageNum(ULONG sequence) noexcept;