Don't resize block store block file to max size at creation (#193)

* Don't resize block store block file to max size at creation
* changelog

1 files changed, 7 insertions, 6 deletions

diff --git a/zenstore/blockstore.cpp b/zenstore/blockstore.cpp
index 38371124d..682cc4472 100644
--- a/zenstore/blockstore.cpp
+++ b/zenstore/blockstore.cpp
@@ -57,12 +57,11 @@ BlockStoreFile::Create(uint64_t InitialSize)
 	}
 
 	m_File.Open(m_Path, BasicFile::Mode::kTruncateDelete);
-	if (InitialSize > 0)
-	{
-		m_File.SetFileSize(InitialSize);
-	}
 	void* FileHandle = m_File.Handle();
-	m_IoBuffer		 = IoBuffer(IoBuffer::File, FileHandle, 0, InitialSize);
+
+	// We map our m_IoBuffer beyond the file size as we will grow it over time and want
+	// to be able to create sub-buffers of all the written range later
+	m_IoBuffer = IoBuffer(IoBuffer::File, FileHandle, 0, InitialSize);
 }
 
 uint64_t
@@ -204,6 +203,7 @@ BlockStore::Close()
 	m_WriteBlock		  = nullptr;
 	m_CurrentInsertOffset = 0;
 	m_WriteBlockIndex	  = 0;
+
 	m_ChunkBlocks.clear();
 	m_BlocksBasePath.clear();
 }
@@ -786,7 +786,7 @@ TEST_CASE("blockstore.blockfile")
 	{
 		BlockStoreFile File1(RootDirectory / "1");
 		File1.Create(16384);
-		CHECK(File1.FileSize() == 16384);
+		CHECK(File1.FileSize() == 0);
 		File1.Write("data", 5, 0);
 		IoBuffer DataChunk = File1.GetChunk(0, 5);
 		File1.Write("boop", 5, 5);
@@ -796,6 +796,7 @@ TEST_CASE("blockstore.blockfile")
 		const char* Boop = static_cast<const char*>(BoopChunk.GetData());
 		CHECK(std::string(Boop) == "boop");
 		File1.Flush();
+		CHECK(File1.FileSize() == 10);
 	}
 	{
 		BlockStoreFile File1(RootDirectory / "1");