Delegate VRS split file creation handling to WriteFileHandler

Summary: Let the WriteFileHandler handle the creation of split file's file body, and avoid re-parsing the upload path as FileSpec.

Reviewed By: kiminoue7

Differential Revision: D50109311

fbshipit-source-id: 9afcba792fc60404b1a38866016f67af452aae1a

vrs/RecordFileWriter.cpp

@@ -854,12 +854,7 @@ int RecordFileWriter::createFile(const string& filePath, bool splitHead) {
 
   if (splitHead) {
     IF_ERROR_LOG_CLOSE_AND_RETURN(indexRecordWriter_.createSplitIndexRecord(lastRecordSize_))
-    // create the (first) user record chunk
-    if (spec.chunks.size() == 1) {
-      IF_ERROR_LOG_CLOSE_AND_RETURN(file_->create(spec.chunks.front() + "_1"))
-    } else {
-      IF_ERROR_LOG_CLOSE_AND_RETURN(file_->create(filePath))
-    }
+    IF_ERROR_LOG_CLOSE_AND_RETURN(file_->createSplitFile(spec, filePath));
   } else if (preliminaryIndex_ && !preliminaryIndex_->empty()) {
     // only use this preliminary index once
     unique_ptr<deque<IndexRecord::DiskRecordInfo>> index = std::move(preliminaryIndex_);

vrs/WriteFileHandler.h

@@ -46,6 +46,19 @@ class WriteFileHandler : public FileHandler {
   /// @return A status code, 0 meaning success.
   virtual int create(const string& newFilePath) = 0;
 
+  /// Create a new file for writing, in split-head file mode, the body part.
+  /// @param spec: spec as converted already from initialFilePath, if that helps.
+  /// @param initialFilePath: path as given when the file creation was started.
+  /// @return A status code, 0 meaning success.
+  virtual int createSplitFile(const FileSpec& spec, const string& initialFilePath) {
+    // create the (first) user record chunk
+    if (spec.chunks.size() == 1) {
+      return create(spec.chunks.front() + "_1");
+    } else {
+      return create(initialFilePath);
+    }
+  }
+
   /// Tell if modifying files is supported by this FileHandler implementation.
   /// @return True if file modification and creation is supported.
   virtual bool reopenForUpdatesSupported() const = 0;