Bug 1637742 - P2 - IPCBlobInputStream does not return error and executes callback on AsyncWait/AsyncLengthWait if stream is closed r=baku

Depends on D77407

Differential Revision: https://phabricator.services.mozilla.com/D77408

dom/file/ipc/IPCBlobInputStream.cpp

@@ -431,16 +431,26 @@ IPCBlobInputStream::AsyncWait(nsIInputStreamCallback* aCallback,
         break;
       }
 
-      // Stream is closed.
+      case eClosed:
+        [[fallthrough]];
       default:
         MOZ_ASSERT(mState == eClosed);
-        return NS_BASE_STREAM_CLOSED;
+        if (mInputStreamCallback && aCallback) {
+          return NS_ERROR_FAILURE;
+        }
+        break;
     }
   }
 
-  MOZ_ASSERT(asyncRemoteStream);
-  return asyncRemoteStream->AsyncWait(aCallback ? this : nullptr, 0, 0,
-                                      aEventTarget);
+  if (asyncRemoteStream) {
+    return asyncRemoteStream->AsyncWait(aCallback ? this : nullptr, 0, 0,
+                                        aEventTarget);
+  }
+
+  // if asyncRemoteStream is nullptr here, that probably means the stream has
+  // been closed and the callback can be executed immediately
+  InputStreamCallbackRunnable::Execute(aCallback, aEventTarget, this);
+  return NS_OK;
 }
 
 void IPCBlobInputStream::StreamReady(
@@ -803,38 +813,6 @@ IPCBlobInputStream::Length(int64_t* aLength) {
   return NS_BASE_STREAM_WOULD_BLOCK;
 }
 
-// nsIAsyncInputStreamLength
-
-NS_IMETHODIMP
-IPCBlobInputStream::AsyncLengthWait(nsIInputStreamLengthCallback* aCallback,
-                                    nsIEventTarget* aEventTarget) {
-  MutexAutoLock lock(mMutex);
-
-  if (mState == eClosed) {
-    return NS_BASE_STREAM_CLOSED;
-  }
-
-  if (mConsumed) {
-    return NS_ERROR_NOT_AVAILABLE;
-  }
-
-  // If we have the callback, we must have the event target.
-  if (NS_WARN_IF(!!aCallback != !!aEventTarget)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  MOZ_ASSERT(mActor);
-
-  mLengthCallback = aCallback;
-  mLengthCallbackEventTarget = aEventTarget;
-
-  if (aCallback) {
-    mActor->LengthNeeded(this, aEventTarget);
-  }
-
-  return NS_OK;
-}
-
 namespace {
 
 class InputStreamLengthCallbackRunnable final : public CancelableRunnable {
@@ -879,6 +857,39 @@ class InputStreamLengthCallbackRunnable final : public CancelableRunnable {
 
 }  // namespace
 
+// nsIAsyncInputStreamLength
+
+NS_IMETHODIMP
+IPCBlobInputStream::AsyncLengthWait(nsIInputStreamLengthCallback* aCallback,
+                                    nsIEventTarget* aEventTarget) {
+  // If we have the callback, we must have the event target.
+  if (NS_WARN_IF(!!aCallback != !!aEventTarget)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    mLengthCallback = aCallback;
+    mLengthCallbackEventTarget = aEventTarget;
+
+    if (mState != eClosed && !mConsumed) {
+      MOZ_ASSERT(mActor);
+
+      if (aCallback) {
+        mActor->LengthNeeded(this, aEventTarget);
+      }
+
+      return NS_OK;
+    }
+  }
+
+  // If execution has reached here, it means the stream is either closed or
+  // consumed, and therefore the callback can be executed immediately
+  InputStreamLengthCallbackRunnable::Execute(aCallback, aEventTarget, this, -1);
+  return NS_OK;
+}
+
 void IPCBlobInputStream::LengthReady(int64_t aLength) {
   nsCOMPtr<nsIInputStreamLengthCallback> lengthCallback;
   nsCOMPtr<nsIEventTarget> lengthCallbackEventTarget;
@@ -886,19 +897,20 @@ void IPCBlobInputStream::LengthReady(int64_t aLength) {
   {
     MutexAutoLock lock(mMutex);
 
-    // We have been closed in the meantime.
+    // Stream has been closed in the meantime. Callback can be executed
+    // immediately
     if (mState == eClosed || mConsumed) {
-      return;
-    }
+      aLength = -1;
+    } else {
+      if (mStart > 0) {
+        aLength -= mStart;
+      }
 
-    if (mStart > 0) {
-      aLength -= mStart;
-    }
-
-    if (mLength < mActor->Size()) {
-      // If the remote stream must be sliced, we must return here the correct
-      // value.
-      aLength = XPCOM_MIN(aLength, (int64_t)mLength);
+      if (mLength < mActor->Size()) {
+        // If the remote stream must be sliced, we must return here the correct
+        // value.
+        aLength = XPCOM_MIN(aLength, (int64_t)mLength);
+      }
     }
 
     lengthCallback.swap(mLengthCallback);