From 1b355d8a87a3ad43bf240aa66b88eb98c1cd777f Mon Sep 17 00:00:00 2001
From: David Sherret <dsherret@users.noreply.github.com>
Date: Wed, 5 Jun 2024 15:17:35 -0400
Subject: refactor(npm): improve locking around updating npm resolution
 (#24104)

Introduces a `SyncReadAsyncWriteLock` to make it harder to write to the
npm resolution without first waiting async in a queue. For the npm
resolution, reading synchronously is fine, but when updating, someone
should wait async, clone the data, then write the data at the end back.
---
 cli/npm/managed/cache/value_creator.rs | 101 ---------------------------------
 1 file changed, 101 deletions(-)
 delete mode 100644 cli/npm/managed/cache/value_creator.rs

(limited to 'cli/npm/managed/cache/value_creator.rs')

diff --git a/cli/npm/managed/cache/value_creator.rs b/cli/npm/managed/cache/value_creator.rs
deleted file mode 100644
index 38801b3aa..000000000
--- a/cli/npm/managed/cache/value_creator.rs
+++ /dev/null
@@ -1,101 +0,0 @@
-// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
-
-use std::sync::Arc;
-
-use deno_core::error::AnyError;
-use deno_core::futures::future::BoxFuture;
-use deno_core::futures::future::LocalBoxFuture;
-use deno_core::futures::future::Shared;
-use deno_core::futures::FutureExt;
-use deno_core::parking_lot::Mutex;
-use tokio::task::JoinError;
-
-// todo(dsherret): unit test this
-
-type FutureResult<TResult> = Result<TResult, Arc<AnyError>>;
-type JoinResult<TResult> = Result<FutureResult<TResult>, Arc<JoinError>>;
-
-#[derive(Debug)]
-struct State<TResult> {
-  retry_index: usize,
-  future: Shared<BoxFuture<'static, JoinResult<TResult>>>,
-}
-
-/// Attempts to create a shared value asynchronously on one tokio runtime while
-/// many runtimes are requesting the value.
-///
-/// This is only useful when the value needs to get created once across
-/// many runtimes.
-///
-/// This handles the case where one tokio runtime goes down while another
-/// one is still running.
-#[derive(Debug)]
-pub struct MultiRuntimeAsyncValueCreator<TResult: Send + Clone + 'static> {
-  state: Mutex<State<TResult>>,
-}
-
-impl<TResult: Send + Clone + 'static> MultiRuntimeAsyncValueCreator<TResult> {
-  pub fn new(
-    future: LocalBoxFuture<'static, Result<TResult, AnyError>>,
-  ) -> Self {
-    Self {
-      state: Mutex::new(State {
-        retry_index: 0,
-        future: Self::create_shared_future(future),
-      }),
-    }
-  }
-
-  pub async fn get(
-    &self,
-    recreate_future: impl Fn() -> LocalBoxFuture<'static, Result<TResult, AnyError>>,
-  ) -> Result<TResult, Arc<AnyError>> {
-    let (mut future, mut retry_index) = {
-      let state = self.state.lock();
-      (state.future.clone(), state.retry_index)
-    };
-
-    loop {
-      let result = future.await;
-
-      match result {
-        Ok(result) => return result,
-        Err(join_error) => {
-          if join_error.is_cancelled() {
-            let mut state = self.state.lock();
-
-            if state.retry_index == retry_index {
-              // we were the first one to retry, so create a new future
-              // that we'll run from the current runtime
-              state.retry_index += 1;
-              state.future = Self::create_shared_future(recreate_future());
-            }
-
-            retry_index = state.retry_index;
-            future = state.future.clone();
-
-            // just in case we're stuck in a loop
-            if retry_index > 1000 {
-              panic!("Something went wrong.") // should never happen
-            }
-          } else {
-            panic!("{}", join_error);
-          }
-        }
-      }
-    }
-  }
-
-  fn create_shared_future(
-    future: LocalBoxFuture<'static, Result<TResult, AnyError>>,
-  ) -> Shared<BoxFuture<'static, JoinResult<TResult>>> {
-    deno_core::unsync::spawn(future)
-      .map(|result| match result {
-        Ok(Ok(value)) => Ok(Ok(value)),
-        Ok(Err(err)) => Ok(Err(Arc::new(err))),
-        Err(err) => Err(Arc::new(err)),
-      })
-      .boxed()
-      .shared()
-  }
-}
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