safer path from handle (#195)

* remove PathFromHandle that throws to give better context on failures

1 files changed, 41 insertions, 31 deletions

diff --git a/src/zenstore/filecas.cpp b/src/zenstore/filecas.cpp
index 57b42beb2..6d5bcff96 100644
--- a/src/zenstore/filecas.cpp
+++ b/src/zenstore/filecas.cpp
@@ -459,41 +459,30 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash, CasStore::
 				 ChunkHash);
 
 #elif ZEN_PLATFORM_LINUX || ZEN_PLATFORM_MAC
-
-		std::filesystem::path SourcePath = PathFromHandle(FileRef.FileHandle);
-		std::filesystem::path DestPath	 = Name.ShardedPath.c_str();
-		int					  Ret		 = link(SourcePath.c_str(), DestPath.c_str());
-		if (Ret < 0 && zen::GetLastError() == ENOENT)
+		std::error_code		  Ec;
+		std::filesystem::path SourcePath = PathFromHandle(FileRef.FileHandle, Ec);
+		if (Ec)
 		{
-			// Destination directory doesn't exist. Create it any try again.
-			CreateDirectories(DestPath.parent_path().c_str());
-			Ret = link(SourcePath.c_str(), DestPath.c_str());
+			ZEN_WARN("link of CAS payload file {} failed ('{}'), falling back to regular write for insert of {}",
+					 FileRef.FileHandle,
+					 Ec.message(),
+					 ChunkHash);
 		}
-		if (Ret == 0)
+		else
 		{
-			m_CasLog.Append({.Key = ChunkHash, .Size = Chunk.Size()});
-			Chunk.SetDeleteOnClose(false);
-
-			HashLock.ReleaseNow();
-			bool IsNew = false;
+			std::filesystem::path DestPath = Name.ShardedPath.c_str();
+			int					  Ret	   = link(SourcePath.c_str(), DestPath.c_str());
+			if (Ret < 0 && zen::GetLastError() == ENOENT)
 			{
-				RwLock::ExclusiveLockScope __(m_Lock);
-				IsNew = m_Index.insert({ChunkHash, IndexEntry{.Size = Chunk.Size()}}).second;
+				// Destination directory doesn't exist. Create it any try again.
+				CreateDirectories(DestPath.parent_path().c_str());
+				Ret = link(SourcePath.c_str(), DestPath.c_str());
 			}
-			if (IsNew)
+			if (Ret == 0)
 			{
-				m_TotalSize.fetch_add(Chunk.Size(), std::memory_order::relaxed);
-			}
-			return CasStore::InsertResult{.New = IsNew};
-		}
-		else
-		{
-			int LinkError = zen::GetLastError();
+				m_CasLog.Append({.Key = ChunkHash, .Size = Chunk.Size()});
+				Chunk.SetDeleteOnClose(false);
 
-			// It is possible that someone beat us to it in linking the file. In that
-			// case a "file exists" error is okay. All others are not.
-			if (LinkError == EEXIST)
-			{
 				HashLock.ReleaseNow();
 				bool IsNew = false;
 				{
@@ -506,10 +495,31 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash, CasStore::
 				}
 				return CasStore::InsertResult{.New = IsNew};
 			}
+			else
+			{
+				int LinkError = zen::GetLastError();
 
-			ZEN_WARN("link of CAS payload file failed ('{}'), falling back to regular write for insert of {}",
-					 GetSystemErrorAsString(LinkError),
-					 ChunkHash);
+				// It is possible that someone beat us to it in linking the file. In that
+				// case a "file exists" error is okay. All others are not.
+				if (LinkError == EEXIST)
+				{
+					HashLock.ReleaseNow();
+					bool IsNew = false;
+					{
+						RwLock::ExclusiveLockScope __(m_Lock);
+						IsNew = m_Index.insert({ChunkHash, IndexEntry{.Size = Chunk.Size()}}).second;
+					}
+					if (IsNew)
+					{
+						m_TotalSize.fetch_add(Chunk.Size(), std::memory_order::relaxed);
+					}
+					return CasStore::InsertResult{.New = IsNew};
+				}
+
+				ZEN_WARN("link of CAS payload file failed ('{}'), falling back to regular write for insert of {}",
+						 GetSystemErrorAsString(LinkError),
+						 ChunkHash);
+			}
 		}
 #endif	// ZEN_PLATFORM_*
 	}