From 7cbf5439b7e51c876774ba0e7a463f4c4e0c8f92 Mon Sep 17 00:00:00 2001
From: Dmitry <b4tm4n@mail.ru>
Date: Tue, 8 Aug 2023 14:20:40 +0300
Subject: [PATCH] rewrite SourceQuestionsZipReaderAsync

"impl Stream for SourceQuestionsZipReaderAsync" dropped
---
 lib/src/source.rs | 99 ++++++++++++++++++++---------------------------
 1 file changed, 41 insertions(+), 58 deletions(-)

diff --git a/lib/src/source.rs b/lib/src/source.rs
index 9217b15..81d02dc 100644
--- a/lib/src/source.rs
+++ b/lib/src/source.rs
@@ -216,16 +216,10 @@ pub use reader_sync::{ReadSourceQuestionsBatches, SourceQuestionsZipReader};
 
 #[cfg(feature = "source_async")]
 pub mod reader_async {
-    use crate::util::ErrorToString;
-
     use async_stream::stream;
     use async_zip::tokio::read::seek::ZipFileReader;
     use futures_core::stream::Stream;
-    use futures_core::Future;
-    use futures_util::{pin_mut, AsyncReadExt, StreamExt};
-
-    use std::pin::Pin;
-    use std::task::{Context, Poll};
+    use futures_util::AsyncReadExt;
 
     use tokio::io::{AsyncRead, AsyncSeek};
 
@@ -249,29 +243,30 @@ pub mod reader_async {
                 index: None,
             }
         }
-        pub async fn get_next(
+
+        pub fn len(&self) -> usize {
+            self.zipfile.file().entries().len()
+        }
+
+        pub fn is_empty(&self) -> bool {
+            self.len() == 0
+        }
+
+        pub async fn get(
             &mut self,
-        ) -> Option<Result<(String, Result<SourceQuestionsBatch, serde_json::Error>), String>>
+            index: usize,
+        ) -> Result<(String, Result<SourceQuestionsBatch, serde_json::Error>), String>
         where
             R: AsyncRead + AsyncSeek + Unpin,
         {
-            let len = self.zipfile.file().entries().len();
-            if self.index.is_none() && len > 0 {
-                self.index = Some(0);
+            let len = self.len();
+            if index >= len {
+                return Err(format!("get index={index}, when len={len}"));
             }
 
-            let index = &mut self.index;
-            if index.unwrap() == len {
-                return None;
-            }
-
-            let reader = self
-                .zipfile
-                .reader_with_entry(self.index.unwrap())
-                .await;
+            let reader = self.zipfile.reader_with_entry(index).await;
             if let Err(error) = reader {
-                println!("{:#?}", error); // DEBUG
-                return Some(Err(error.to_string()))
+                return Err(format!("reader_with_entry: {error:?}"));
             }
             let mut reader = reader.unwrap();
 
@@ -279,14 +274,34 @@ pub mod reader_async {
             let mut data: Vec<u8> = Vec::new();
             let readed = reader.read_to_end(&mut data).await;
             if let Err(error) = readed {
-                return Some(Err(error.to_string()))
+                return Err(format!("read_to_end: {error:?}"));
             }
             let parsed: Result<SourceQuestionsBatch, _> = serde_json::from_slice(&data);
+            Ok((filename, parsed))
+        }
+        pub async fn get_next(
+            &mut self,
+        ) -> Option<Result<(String, Result<SourceQuestionsBatch, serde_json::Error>), String>>
+        where
+            R: AsyncRead + AsyncSeek + Unpin,
+        {
+            if self.index.is_none() && !self.is_empty() {
+                self.index = Some(0);
+            }
+
+            if self.index.unwrap() >= self.len() {
+                return None;
+            }
+
+            let item = self.get(self.index.unwrap()).await;
             self.index = Some(self.index.unwrap() + 1);
 
-            Some(Ok((filename, parsed)))
+            Some(item)
         }
-        pub fn stream(&mut self) -> impl Stream<Item = (String, Result<SourceQuestionsBatch, serde_json::Error>)> + '_ {
+        pub fn stream(
+            &mut self,
+        ) -> impl Stream<Item = (String, Result<SourceQuestionsBatch, serde_json::Error>)> + '_
+        {
             stream! {
                 while let Some(Ok(item)) = self.get_next().await {
                     yield item
@@ -295,38 +310,6 @@ pub mod reader_async {
         }
     }
 
-    impl<R> Stream for SourceQuestionsZipReaderAsync<R>
-    where
-        R: AsyncRead + AsyncSeek + Unpin,
-    {
-        type Item = (String, Result<SourceQuestionsBatch, serde_json::Error>);
-
-        fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-            let future = self.stream();
-            pin_mut!(future);
-            match Pin::new(&mut future.next()).poll(cx) {
-                Poll::Ready(Some(item)) => Poll::Ready(Some(item)),
-                Poll::Ready(None) => Poll::Ready(None),
-                Poll::Pending => Poll::Pending,
-            }
-        }
-
-        fn size_hint(&self) -> (usize, Option<usize>) {
-            let len = self.zipfile.file().entries().len();
-            if self.index.is_none() {
-                return (len, Some(len));
-            }
-
-            let index = self.index.unwrap();
-            let rem = if len > index + 1 {
-                len - (index + 1)
-            } else {
-                0
-            };
-            (rem, Some(rem))
-        }
-    }
-
     pub trait ReadSourceQuestionsBatchesAsync<R>
     where
         R: AsyncRead + AsyncSeek + Unpin,