add doc comments and clean up code

apache · Jul 11, 2021 · f52d13e · f52d13e
1 parent 85cda50
commit f52d13e
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Showing 6 changed files with 7 additions and 38 deletions.
diff --git a/arrow/src/array/array_map.rs b/arrow/src/array/array_map.rs
@@ -26,6 +26,11 @@ use super::{
 use crate::datatypes::{ArrowNativeType, DataType};
 use crate::error::ArrowError;
 
+/// A nested array type where each record is a key-value map.
+/// Keys should always be non-null, but values can be null.
+///
+/// [MapArray] is physically a [ListArray] that has a [StructArray]
+/// with 2 child fields.
 pub struct MapArray {
     data: ArrayData,
     values: ArrayRef,

diff --git a/arrow/src/array/builder.rs b/arrow/src/array/builder.rs
@@ -1644,38 +1644,6 @@ impl<K: ArrayBuilder, V: ArrayBuilder> MapBuilder<K, V> {
         }
     }
 
-    // /// Try to create a `MapBuilder` from a [Field].
-    // ///
-    // /// Returns an error if the fild is not a Struct, or keys are nullable
-    // pub fn try_from_field(field: Field, capacity: usize) -> Result<Self> {
-    //     if let DataType::Struct(fields) = field.data_type() {
-    //         if fields.len() != 2 {
-    //             return Err(ArrowError::InvalidArgumentError(format!(
-    //                 "MapArray's struct field should have 2 child fields, found {}",
-    //                 fields.len()
-    //             )));
-    //         }
-    //         let keys_field = &fields[0];
-    //         let values_field = &fields[1];
-    //         let field_names = MapFieldNames {
-    //             entry: field.name().clone(),
-    //             key: keys_field.name().clone(),
-    //             value: values_field.name().clone(),
-    //         };
-    //         Ok(Self::with_capacity(
-    //             Some(field_names),
-    //             *make_builder(keys_field.data_type(), capacity),
-    //             *make_builder(values_field.data_type(), capacity),
-    //             capacity,
-    //         ))
-    //     } else {
-    //         Err(ArrowError::InvalidArgumentError(format!(
-    //             "Cannot create MapArray from {:?}",
-    //             field.data_type()
-    //         )))
-    //     }
-    // }
-
     pub fn keys(&mut self) -> &mut K {
         &mut self.key_builder
     }

diff --git a/arrow/src/ipc/convert.rs b/arrow/src/ipc/convert.rs
@@ -312,7 +312,7 @@ pub(crate) fn get_data_type(field: ipc::Field, may_be_dictionary: bool) -> DataT
             let map = field.type_as_map().unwrap();
             let children = field.children().unwrap();
             if children.len() != 1 {
-                panic!("expect a list to have one child")
+                panic!("expect a map to have one child")
             }
             DataType::Map(Box::new(children.get(0).into()), map.keysSorted())
         }

diff --git a/arrow/src/ipc/reader.rs b/arrow/src/ipc/reader.rs
@@ -389,7 +389,7 @@ fn create_list_array(
         }
         make_array(builder.build())
     } else {
-        panic!("Cannot create list array from {:?}", data_type)
+        panic!("Cannot create list or map array from {:?}", data_type)
     }
 }
 

diff --git a/parquet/src/arrow/array_reader.rs b/parquet/src/arrow/array_reader.rs
@@ -1047,8 +1047,6 @@ impl ArrayReader for MapArrayReader {
             .add_child_data(entry_data)
             .build();
 
-        // self.def_level_buffer = Some(def_level_data_buffer.into());
-        // self.rep_level_buffer = rep_level_data;
         Ok(Arc::new(MapArray::from(array_data)))
     }
 

diff --git a/parquet/src/arrow/arrow_writer.rs b/parquet/src/arrow/arrow_writer.rs
@@ -952,8 +952,6 @@ mod tests {
         {"stocks":{"long": null, "long": "$CCC", "short": null}}
         {"stocks":{"hedged": "$YYY", "long": null, "short": "$D"}}
         "#;
-        // let value_list_type =
-        //     DataType::List(Box::new(Field::new("item", DataType::Utf8, false)));
         let entries_struct_type = DataType::Struct(vec![
             Field::new("key", DataType::Utf8, false),
             Field::new("value", DataType::Utf8, true),