[GitHub] [arrow] heymind commented on a change in pull request #10066: ARROW-12306: [Rust][datafusion] Read CSV format text from stdin or memory

[GitBox <gi...@apache.org>]

heymind commented on a change in pull request #10066:
URL: https://github.com/apache/arrow/pull/10066#discussion_r615542436



##########
File path: rust/datafusion/src/physical_plan/csv.rs
##########
@@ -106,13 +107,71 @@ impl<'a> CsvReadOptions<'a> {
     }
 }
 
+///  SourceReader represents where the data comes from.
+enum SourceReader {
+    /// The data comes from partitioned files
+    PartitionedFiles {
+        /// Path to directory containing partitioned files with the same schema
+        path: String,
+        /// The individual files under path
+        filenames: Vec<String>,
+    },
+
+    /// The data comes from anything impl Read trait
+    Reader(Mutex<Option<Box<dyn Read + Send + Sync + 'static>>>),
+}
+
+impl std::fmt::Debug for SourceReader {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SourceReader::PartitionedFiles { path, filenames } => f
+                .debug_struct("PartitionedFiles")
+                .field("path", path)
+                .field("filenames", filenames)
+                .finish()?,
+            SourceReader::Reader(_) => f.write_str("Reader")?,
+        };
+        Ok(())
+    }
+}
+
+impl Clone for SourceReader {
+    fn clone(&self) -> Self {
+        match self {
+            SourceReader::PartitionedFiles { path, filenames } => {
+                Self::PartitionedFiles {
+                    path: path.clone(),
+                    filenames: filenames.clone(),
+                }
+            }
+            SourceReader::Reader(_) => Self::Reader(Mutex::new(None)),

Review comment:
       I agree it's unnecessary for `CsvExec` to be `Clone`. But if we remove the `Clone` derivation, will it introduce a breaking change ? 
   
   If the `CsvExec` is built from source files ( not from a reader ) , the `Clone` will act as expected.




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