1 files changed, 69 insertions, 0 deletions
diff --git a/devtools/client/debugger/src/reducers/threads.js b/devtools/client/debugger/src/reducers/threads.js
new file mode 100644
index 0000000000..0131c6c7e8
--- /dev/null
+++ b/devtools/client/debugger/src/reducers/threads.js
@@ -0,0 +1,69 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+/**
+ * Threads reducer
+ * @module reducers/threads
+ */
+
+export function initialThreadsState() {
+  return {
+    threads: [],
+
+    // List of thread actor IDs which are current tracing.
+    // i.e. where JavaScript tracing is enabled.
+    mutableTracingThreads: new Set(),
+  };
+}
+
+export default function update(state = initialThreadsState(), action) {
+  switch (action.type) {
+    case "INSERT_THREAD":
+      return {
+        ...state,
+        threads: [...state.threads, action.newThread],
+      };
+
+    case "REMOVE_THREAD":
+      return {
+        ...state,
+        threads: state.threads.filter(
+          thread => action.threadActorID != thread.actor
+        ),
+      };
+
+    case "UPDATE_SERVICE_WORKER_STATUS":
+      return {
+        ...state,
+        threads: state.threads.map(t => {
+          if (t.actor == action.thread) {
+            return { ...t, serviceWorkerStatus: action.status };
+          }
+          return t;
+        }),
+      };
+
+    case "TRACING_TOGGLED":
+      const { mutableTracingThreads } = state;
+      const sizeBefore = mutableTracingThreads.size;
+      if (action.enabled) {
+        mutableTracingThreads.add(action.thread);
+      } else {
+        mutableTracingThreads.delete(action.thread);
+      }
+      // We may receive toggle events when we change the logging method
+      // while we are already tracing, but the list of tracing thread stays the same.
+      const changed = mutableTracingThreads.size != sizeBefore;
+      if (changed) {
+        return {
+          ...state,
+          mutableTracingThreads,
+        };
+      }
+      return state;
+
+    default:
+      return state;
+  }
+}