perform a perfect backflip

This replaces the join set with a futures stream but does not fulfill the goal of scanning ahead with a cap.

src/main.rs

@@ -1462,6 +1462,12 @@ fn script_builder(class:&str,name:&str,source:String)->rbx_dom_weak::InstanceBui
 	builder
 }
 
+enum TooComplicated<T>{
+	Stop,
+	Value(T),
+	Skip,
+}
+
 async fn compile(config:CompileConfig)->AResult<()>{
 	//basically decompile in reverse order
 	//load template dom
@@ -1490,7 +1496,7 @@ async fn compile(config:CompileConfig)->AResult<()>{
 				folder.push(sans.as_str());
 				stack.push(CompileStackInstruction::PopFolder);
 				//check if a folder exists with item.name
-				if let Ok(mut dir)=tokio::fs::read_dir(folder.as_path()).await{
+				if let Ok(dir)=tokio::fs::read_dir(folder.as_path()).await{
 					let mut exist_names:std::collections::HashSet<String>={
 						let item=dom.get_by_ref(item_ref).ok_or(anyhow::Error::msg("null child ref"))?;
 						//push existing dom children objects onto stack (unrelated to exist_names)
@@ -1505,49 +1511,73 @@ async fn compile(config:CompileConfig)->AResult<()>{
 						exist_names.insert(dont);
 					}
 					//generate children from folder contents UNLESS! item already has a child of the same name
-					let mut join_set=tokio::task::JoinSet::new();
+
-					//I wish I could make the join_next() loop begin processing immediately,
+					let style=config.style;
-					//but I don't know an ergonomic way to do that.
+					let exist_names=&exist_names;
-					//this will probably be fine considering there won't be millions of files in the directories
+					//thread the needle! follow the patch that dir takes!
-					while let Some(entry)=dir.next_entry().await?{
+					let u=futures::stream::unfold(dir,|mut dir1|async{
+						let ret1={
+							//capture a scoped mutable reference so we can forward dir to the next call even on an error
+							let dir2=&mut dir1;
+							(||async move{//error catcher so I can use ?
+								let ret2=if let Some(entry)=dir2.next_entry().await?{
 									//cull early even if supporting things with identical names is possible
 									if !exist_names.contains(entry.file_name().to_str().unwrap()){
-							let style=config.style;
-							join_set.spawn(async move{
 										let met=entry.metadata().await?;
+										//discern that bad boy
 										let compile_class=match met.is_dir(){
 											true=>locate_override_file(&entry,style).await?,
 											false=>discern_file(&entry,style).await?,
 										};
-								//discern that bad boy
-								Ok::<_,anyhow::Error>(
 										//prepare data structure
-									(compile_class.blacklist,match compile_class.class{
+										TooComplicated::Value((compile_class.blacklist,match compile_class.class{
 											CompileClass::Folder=>PreparedData::Builder(rbx_dom_weak::InstanceBuilder::new("Folder").with_name(compile_class.name.as_str())),
 											CompileClass::Script(source)=>PreparedData::Builder(script_builder("Script",compile_class.name.as_str(),source)),
 											CompileClass::LocalScript(source)=>PreparedData::Builder(script_builder("LocalScript",compile_class.name.as_str(),source)),
 											CompileClass::ModuleScript(source)=>PreparedData::Builder(script_builder("ModuleScript",compile_class.name.as_str(),source)),
 											CompileClass::Model(buf)=>PreparedData::Model(rbx_xml::from_reader_default(std::io::Cursor::new(buf))?),
-									})
+										}))
-								)
+									}else{
+										TooComplicated::Skip
+									}
+								}else{
+									TooComplicated::Stop
+								};
+								Ok::<_,anyhow::Error>(ret2)
+							})().await
+						};
+						match ret1{
+							Ok(TooComplicated::Stop)=>None,
+							Ok(TooComplicated::Skip)=>Some((Ok(None),dir1)),
+							Ok(TooComplicated::Value(v))=>Some((Ok(Some(v)),dir1)),
+							Err(e)=>Some((Err(e),dir1)),
+						}
 					});
-						}
+
-					}
+					//why can't I do this? is this even what I want?
-					//push child objects onto dom
+					//let u=u.buffer_unordered(32);
-					//this is only able to begin after dir iterator is exhausted
+
-					while let Some(goober)=join_set.join_next().await{
+					//begin processing immediately
-						let (blacklist,data)=goober??;
+					u.fold((&mut stack,&mut dom),|(stack,dom),bog:Result<_,anyhow::Error>|async{
+						//push child objects onto dom serially as they arrive
+						match bog{
+							Ok(Some((blacklist,data)))=>{
 								let referent=match data{
 									PreparedData::Model(mut model_dom)=>{
 										let referent=model_dom.root().children()[0];
-								model_dom.transfer(referent,&mut dom,item_ref);
+										model_dom.transfer(referent,dom,item_ref);
 										referent
 									},
 									PreparedData::Builder(script)=>dom.insert(item_ref,script),
 								};
 								//new children need to be traversed
 								stack.push(CompileStackInstruction::TraverseReferent(referent,blacklist));
+							},
+							Ok(None)=>println!("entry skipped"),
+							Err(e)=>println!("error lole {e:?}"),
 						}
+						(stack,dom)
+					}).await;
 				}
 			},
 			CompileStackInstruction::PopFolder=>assert!(folder.pop(),"pop folder bad"),