Reset the interruptSignal after acquiring the lock in completion and …

…chatCompletion. It was doing this in effect within asyncGenerate, and kind of in generate, but the completion code would never call generate if interruptGenerate was ever called in the past because it would be stuck true. Also do it in a way that allows users to still call interruptGenerate during a context switch of acquiring the model lock.

src/engine.ts

@@ -745,6 +745,8 @@ export class MLCEngine implements MLCEngineInterface {
   async chatCompletion(
     request: ChatCompletionRequest,
   ): Promise<AsyncIterable<ChatCompletionChunk> | ChatCompletion> {
+    const initialInterruptSignal = this.interruptSignal;
+
     // 0. Check model loaded and preprocess inputs
     const [selectedModelId, selectedPipeline, selectedChatConfig] =
       this.getLLMStates("ChatCompletionRequest", request.model);
@@ -771,6 +773,10 @@ export class MLCEngine implements MLCEngineInterface {
     // 0.5 Block wait until this pipeline finishes all previous requests
     const lock = this.loadedModelIdToLock.get(selectedModelId)!;
     await lock.acquire();
+    // If interruptGenerate called during the wait for lock, respect that. But reset if locked from a previous call to interruptGenerate
+    if (initialInterruptSignal && this.interruptSignal) {
+      this.interruptSignal = false;
+    }
 
     // 1. If request is streaming, return an AsyncIterable (an iterable version of `_generate()`)
     if (request.stream) {
@@ -901,6 +907,8 @@ export class MLCEngine implements MLCEngineInterface {
   async completion(
     request: CompletionCreateParams,
   ): Promise<AsyncIterable<Completion> | Completion> {
+    const initialInterruptSignal = this.interruptSignal;
+
     // 0. Check model loaded and preprocess inputs
     const [selectedModelId, selectedPipeline, selectedChatConfig] =
       this.getLLMStates("CompletionCreateParams", request.model);
@@ -920,6 +928,10 @@ export class MLCEngine implements MLCEngineInterface {
     // 0.5 Block wait until this pipeline finishes all previous requests
     const lock = this.loadedModelIdToLock.get(selectedModelId)!;
     await lock.acquire();
+    // If interruptGenerate called during the wait for lock, respect that. But reset if locked from a previous call to interruptGenerate
+    if (initialInterruptSignal && this.interruptSignal) {
+      this.interruptSignal = false;
+    }
 
     // 1. If request is streaming, return an AsyncIterable (an iterable version of `_generate()`)
     if (request.stream) {