json custom decoder support

Author: scovich

arrow-json/Cargo.toml

@@ -54,6 +54,7 @@ ryu = "1.0"
 itoa = "1.0"
 
 [dev-dependencies]
+arrow-select = { workspace = true }
 flate2 = { version = "1", default-features = false, features = ["rust_backend"] }
 serde = { version = "1.0", default-features = false, features = ["derive"] }
 futures = "0.3"

arrow-json/src/lib.rs

@@ -86,7 +86,7 @@
 pub mod reader;
 pub mod writer;
 
-pub use self::reader::{Reader, ReaderBuilder};
+pub use self::reader::{ArrayDecoder, DecoderFactory, Reader, ReaderBuilder, Tape, TapeElement};
 pub use self::writer::{
     ArrayWriter, Encoder, EncoderFactory, EncoderOptions, LineDelimitedWriter, Writer,
     WriterBuilder,

arrow-json/src/reader/list_array.rs

@@ -42,7 +42,7 @@ impl<O: OffsetSizeTrait> ListArrayDecoder<O> {
             DataType::LargeList(f) if O::IS_LARGE => f,
             _ => unreachable!(),
         };
-        let decoder = ctx.make_decoder(field.data_type(), field.is_nullable())?;
+        let decoder = ctx.make_decoder(field.data_type(), field.is_nullable(), field.metadata())?;
 
         Ok(Self {
             data_type: data_type.clone(),

arrow-json/src/reader/map_array.rs

@@ -53,8 +53,16 @@ impl MapArrayDecoder {
             _ => unreachable!(),
         };
 
-        let keys = ctx.make_decoder(fields[0].data_type(), fields[0].is_nullable())?;
-        let values = ctx.make_decoder(fields[1].data_type(), fields[1].is_nullable())?;
+        let keys = ctx.make_decoder(
+            fields[0].data_type(),
+            fields[0].is_nullable(),
+            fields[0].metadata(),
+        )?;
+        let values = ctx.make_decoder(
+            fields[1].data_type(),
+            fields[1].is_nullable(),
+            fields[1].metadata(),
+        )?;
 
         Ok(Self {
             data_type: data_type.clone(),