refactor(core): Cleanup circular dependency between ViewEngine and Ivy Renderer2. (#39710)

mhevery · atscott · commit 9ab3fe732be7 · 2020-11-16T11:17:42.000-08:00
`Renderer2` is declared in ViewEngine but it sub-classed in Ivy. This creates a circular dependency between ViewEngine `Renderer2` which needs to declare `__NG_ELEMENT_ID__` and ivy factory which needs to create it. The workaround used to be to pass the `Renderer2` through stack but that created a very convoluted code. This refactoring simply bundles the two files together and removes the stack workaround making the code simpler to follow. PR Close #39710
diff --git a/goldens/circular-deps/packages.json b/goldens/circular-deps/packages.json
@@ -149,7 +149,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/linker/view_ref.ts"
@@ -163,7 +162,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -181,7 +179,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -206,7 +203,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -233,7 +229,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/assert.ts",
     "packages/core/src/render3/definition.ts",
@@ -883,7 +878,6 @@
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts",
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/linker/view_ref.ts"
@@ -995,31 +989,23 @@
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts"
-  ],
-  [
-    "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -1029,7 +1015,6 @@
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -1038,7 +1023,6 @@
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
@@ -1048,28 +1032,24 @@
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/container.ts",
     "packages/core/src/render3/interfaces/view.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/interfaces/type_checks.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/assert.ts",
     "packages/core/src/render3/interfaces/injector.ts",
@@ -1078,38 +1058,33 @@
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/assert.ts",
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/util/view_utils.ts",
     "packages/core/src/render3/interfaces/context.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/util/view_utils.ts",
     "packages/core/src/render3/interfaces/node.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
   ],
   [
     "packages/core/src/render/api.ts",
-    "packages/core/src/render3/view_engine_compatibility.ts",
     "packages/core/src/render3/state.ts",
     "packages/core/src/render3/util/view_utils.ts",
     "packages/core/src/render3/interfaces/renderer.ts"
diff --git a/packages/core/src/render/api.ts b/packages/core/src/render/api.ts
@@ -8,7 +8,11 @@
 
 import {InjectionToken} from '../di/injection_token';
 import {ViewEncapsulation} from '../metadata/view';
-import {injectRenderer2 as render3InjectRenderer2} from '../render3/view_engine_compatibility';
+import {isProceduralRenderer} from '../render3/interfaces/renderer';
+import {isLView} from '../render3/interfaces/type_checks';
+import {LView, RENDERER} from '../render3/interfaces/view';
+import {getCurrentTNode, getLView} from '../render3/state';
+import {getComponentLViewByIndex} from '../render3/util/view_utils';
 import {noop} from '../util/noop';
 
 
@@ -286,6 +290,25 @@ export abstract class Renderer2 {
 }
 
 
-export const SWITCH_RENDERER2_FACTORY__POST_R3__ = render3InjectRenderer2;
+export const SWITCH_RENDERER2_FACTORY__POST_R3__ = injectRenderer2;
 const SWITCH_RENDERER2_FACTORY__PRE_R3__ = noop;
-const SWITCH_RENDERER2_FACTORY: typeof render3InjectRenderer2 = SWITCH_RENDERER2_FACTORY__PRE_R3__;
+const SWITCH_RENDERER2_FACTORY: typeof injectRenderer2 = SWITCH_RENDERER2_FACTORY__PRE_R3__;
+
+/** Returns a Renderer2 (or throws when application was bootstrapped with Renderer3) */
+function getOrCreateRenderer2(lView: LView): Renderer2 {
+  const renderer = lView[RENDERER];
+  if (ngDevMode && !isProceduralRenderer(renderer)) {
+    throw new Error('Cannot inject Renderer2 when the application uses Renderer3!');
+  }
+  return renderer as Renderer2;
+}
+
+/** Injects a Renderer2 for the current component. */
+export function injectRenderer2(): Renderer2 {
+  // We need the Renderer to be based on the component that it's being injected into, however since
+  // DI happens before we've entered its view, `getLView` will return the parent view instead.
+  const lView = getLView();
+  const tNode = getCurrentTNode()!;
+  const nodeAtIndex = getComponentLViewByIndex(tNode.index, lView);
+  return getOrCreateRenderer2(isLView(nodeAtIndex) ? nodeAtIndex : lView);
+}
diff --git a/packages/core/src/render3/view_engine_compatibility.ts b/packages/core/src/render3/view_engine_compatibility.ts
