[GitHub] [arrow] mqy commented on a change in pull request #9011: ARROW-9777: [Rust] [IPC] write custom metadata [WIP]

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

mqy commented on a change in pull request #9011:
URL: https://github.com/apache/arrow/pull/9011#discussion_r550138436



##########
File path: rust/arrow/src/ipc/writer.rs
##########
@@ -355,41 +381,83 @@ pub struct FileWriter<W: Write> {
 
 impl<W: Write> FileWriter<W> {
     /// Try create a new writer, with the schema written as part of the header
+    #[deprecated(
+        since = "3.0.0",
+        note = "This method is deprecated in favour of `let writer = FileWriter::new(writer, schema); writer.write_header_schema().unwrap();`"
+    )]
     pub fn try_new(writer: W, schema: &Schema) -> Result<Self> {
-        let write_options = IpcWriteOptions::default();
-        Self::try_new_with_options(writer, schema, write_options)
+        let mut me = FileWriter::new(writer, schema);
+        me.write_header_schema()?;
+        Ok(me)
     }
 
     /// Try create a new writer with IpcWriteOptions
+    #[deprecated(
+        since = "3.0.0",
+        note = "This method is deprecated in favour of `let writer = FileWriter::new(writer, schema).with_write_options(opt); w.write_header_schema().unwrap();`"
+    )]
     pub fn try_new_with_options(
         writer: W,
         schema: &Schema,
         write_options: IpcWriteOptions,
     ) -> Result<Self> {
-        let data_gen = IpcDataGenerator::default();
-        let mut writer = BufWriter::new(writer);
-        // write magic to header
-        writer.write_all(&super::ARROW_MAGIC[..])?;
-        // create an 8-byte boundary after the header
-        writer.write_all(&[0, 0])?;
-        // write the schema, set the written bytes to the schema + header
-        let encoded_message = data_gen.schema_to_bytes(schema, &write_options);
-        let (meta, data) = write_message(&mut writer, encoded_message, &write_options)?;
-        Ok(Self {
-            writer,
-            write_options,
+        let mut me = FileWriter::new(writer, schema);
+        me.write_options = write_options;
+        me.write_header_schema()?;
+        Ok(me)
+    }
+
+    /// Creates the FileWriter.
+    pub fn new(writer: W, schema: &Schema) -> Self {

Review comment:
       Agree, so add `metadata` to `IpcWriteOptions`?




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