Bug 1846517 - Part 1:Expose coroutine scope for stores through lazyStore

Bug 1846517 - Part 1:Expose coroutine scope for stores through lazyStore

app/src/main/java/org/mozilla/fenix/components/StoreProvider.kt

@@ -10,19 +10,31 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.ViewModelStoreOwner
 import androidx.lifecycle.get
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.CoroutineScope
 import mozilla.components.lib.state.Store
 
 /**
  * Generic ViewModel to wrap a State object for state restoration.
  *
- * @property store [Store] instance attached to [ViewModel].
+ * @param createStore Function that creates a [Store] instance that receives [CoroutineScope] param
+ * that's tied to the lifecycle of the [StoreProvider] i.e it will cancel when
+ * [StoreProvider.onCleared] is called.
  */
 class StoreProvider<T : Store<*, *>>(
-    val store: T,
+    createStore: (CoroutineScope) -> T,
 ) : ViewModel() {
 
+    @VisibleForTesting
+    internal val store: T = createStore(viewModelScope)
+
     companion object {
-        fun <T : Store<*, *>> get(owner: ViewModelStoreOwner, createStore: () -> T): T {
+        /**
+         * Returns an existing [Store] instance or creates a new one scoped to a
+         * [ViewModelStoreOwner].
+         * @see [ViewModelProvider.get].
+         */
+        fun <T : Store<*, *>> get(owner: ViewModelStoreOwner, createStore: (CoroutineScope) -> T): T {
             val factory = StoreProviderFactory(createStore)
             val viewModel: StoreProvider<T> = ViewModelProvider(owner, factory).get()
             return viewModel.store
@@ -37,23 +49,39 @@ class StoreProvider<T : Store<*, *>>(
  */
 @VisibleForTesting
 class StoreProviderFactory<T : Store<*, *>>(
-    private val createStore: () -> T,
+    private val createStore: (CoroutineScope) -> T,
 ) : ViewModelProvider.Factory {
 
     @Suppress("UNCHECKED_CAST")
     override fun <VM : ViewModel> create(modelClass: Class<VM>): VM {
-        return StoreProvider(createStore()) as VM
+        return StoreProvider(createStore) as VM
     }
 }
 
 /**
  * Helper function for lazy creation of a [Store] instance scoped to a [ViewModelStoreOwner].
  *
- * @param createStore Function that creates a [Store] instance.
+ * @param createStore Function that creates a [Store] instance that receives [CoroutineScope] param
+ * that's tied to the lifecycle of the [StoreProvider] i.e it will cancel when
+ * [StoreProvider.onCleared] is called.
+ *
+ * Example:
+ * ```
+ * val store by lazy { scope ->
+ *   MyStore(
+ *     middleware = listOf(
+ *       MyMiddleware(
+ *         settings = requireComponents.settings,
+ *         ...
+ *         scope = scope,
+ *       ),
+ *     )
+ *   )
+ * }
  */
 @MainThread
 fun <T : Store<*, *>> ViewModelStoreOwner.lazyStore(
-    createStore: () -> T,
+    createStore: (CoroutineScope) -> T,
 ): Lazy<T> {
     return lazy(mode = LazyThreadSafetyMode.NONE) {
         StoreProvider.get(this, createStore)

app/src/test/java/org/mozilla/fenix/components/StoreProviderTest.kt

@@ -5,6 +5,7 @@
 package org.mozilla.fenix.components
 
 import androidx.fragment.app.Fragment
+import kotlinx.coroutines.CoroutineScope
 import mozilla.components.lib.state.Action
 import mozilla.components.lib.state.State
 import mozilla.components.lib.state.Store
@@ -51,7 +52,7 @@ class StoreProviderTest {
         val fragment = createAddedTestFragment { Fragment() }
 
         var createCalled = false
-        val createStore = {
+        val createStore: (CoroutineScope) -> Store<BasicState, Action> = {
             createCalled = true
             basicStore
         }
@@ -69,7 +70,7 @@ class StoreProviderTest {
         val fragment = createAddedTestFragment { Fragment() }
 
         var createCalled = false
-        val createStore = {
+        val createStore: (CoroutineScope) -> Store<BasicState, Action> = {
             createCalled = true
             basicStore
         }