From 94288a7e9c40f9f64627546c70b2316c80bbcbf9 Mon Sep 17 00:00:00 2001
From: alecmocatta <alec@mocatta.net>
Date: Mon, 4 Feb 2019 19:54:08 +0000
Subject: [PATCH] Make RowIter own rather than borrow FileReader

---
 rust/parquet/src/file/reader.rs   | 32 +++++++++++++++++++++----------
 rust/parquet/src/record/reader.rs | 12 ++++++------
 2 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/rust/parquet/src/file/reader.rs b/rust/parquet/src/file/reader.rs
index 11daa55aa9673..e8d45c464ea44 100644
--- a/rust/parquet/src/file/reader.rs
+++ b/rust/parquet/src/file/reader.rs
@@ -71,10 +71,30 @@ pub trait FileReader {
     ///
     /// Projected schema can be a subset of or equal to the file schema, when it is None,
     /// full file schema is assumed.
-    fn get_row_iter<T>(&self, projection: Option<Predicate>) -> Result<RowIter<Self, T>>
+    fn get_row_iter<T>(self, projection: Option<Predicate>) -> Result<RowIter<Self, T>>
     where
         T: Record,
-        Self: Sized;
+        Self: Sized,
+    {
+        RowIter::from_file(projection, self)
+    }
+}
+
+impl<'a, R> FileReader for &'a R
+where
+    R: FileReader,
+{
+    type RowGroupReader = R::RowGroupReader;
+
+    fn metadata(&self) -> ParquetMetaDataPtr {
+        <R as FileReader>::metadata(*self)
+    }
+    fn num_row_groups(&self) -> usize {
+        <R as FileReader>::num_row_groups(*self)
+    }
+    fn get_row_group(&self, i: usize) -> Result<Self::RowGroupReader> {
+        <R as FileReader>::get_row_group(*self, i)
+    }
 }
 
 /// Parquet row group reader API. With this, user can get metadata information about the
@@ -289,14 +309,6 @@ impl<R: 'static + ParquetReader> FileReader for SerializedFileReader<R> {
         let f = self.buf.get_ref().try_clone()?;
         Ok(SerializedRowGroupReader::new(f, row_group_metadata))
     }
-
-    fn get_row_iter<T>(&self, projection: Option<Predicate>) -> Result<RowIter<Self, T>>
-    where
-        T: Record,
-        Self: Sized,
-    {
-        RowIter::from_file(projection, self)
-    }
 }
 
 impl TryFrom<File> for SerializedFileReader<File> {
diff --git a/rust/parquet/src/record/reader.rs b/rust/parquet/src/record/reader.rs
index 49ecb5d0a1596..679c37bda1f57 100644
--- a/rust/parquet/src/record/reader.rs
+++ b/rust/parquet/src/record/reader.rs
@@ -1040,25 +1040,25 @@ where
 ///
 /// It is used either for a single row group to iterate over data in that row group, or
 /// an entire file with auto buffering of all row groups.
-pub struct RowIter<'a, R, T>
+pub struct RowIter<R, T>
 where
     R: FileReader,
     T: Record,
 {
     schema: <Root<T> as Record>::Schema,
-    file_reader: Option<&'a R>,
+    file_reader: Option<R>,
     current_row_group: usize,
     num_row_groups: usize,
     row_iter: Option<ReaderIter<T>>,
 }
 
-impl<'a, R, T> RowIter<'a, R, T>
+impl<R, T> RowIter<R, T>
 where
     R: FileReader,
     T: Record,
 {
     /// Creates row iterator for all row groups in a file.
-    pub fn from_file(_proj: Option<Predicate>, reader: &'a R) -> Result<Self> {
+    pub fn from_file(_proj: Option<Predicate>, reader: R) -> Result<Self> {
         let num_row_groups = reader.num_row_groups();
 
         let file_schema = reader.metadata().file_metadata().schema_descr_ptr();
@@ -1077,7 +1077,7 @@ where
     /// Creates row iterator for a specific row group.
     pub fn from_row_group(
         _proj: Option<Predicate>,
-        row_group_reader: &'a RowGroupReader,
+        row_group_reader: &RowGroupReader,
     ) -> Result<Self> {
         let file_schema = row_group_reader.metadata().schema_descr_ptr();
         let file_schema = file_schema.root_schema();
@@ -1123,7 +1123,7 @@ where
     }
 }
 
-impl<'a, R, T> Iterator for RowIter<'a, R, T>
+impl<R, T> Iterator for RowIter<R, T>
 where
     R: FileReader,
     T: Record,