feat(compiler-cli): reflect static methods added to classes in metadata (#21926)

PR Close #21926

packages/compiler-cli/src/transformers/metadata_cache.ts

@@ -0,0 +1,66 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import * as ts from 'typescript';
+
+import {MetadataCollector, MetadataValue, ModuleMetadata} from '../metadata/index';
+
+import {MetadataProvider} from './compiler_host';
+
+export type ValueTransform = (value: MetadataValue, node: ts.Node) => MetadataValue;
+
+export interface MetadataTransformer {
+  connect?(cache: MetadataCache): void;
+  start(sourceFile: ts.SourceFile): ValueTransform|undefined;
+}
+
+/**
+ * Cache, and potentially transform, metadata as it is being collected.
+ */
+export class MetadataCache implements MetadataProvider {
+  private metadataCache = new Map<string, ModuleMetadata|undefined>();
+
+  constructor(
+      private collector: MetadataCollector, private strict: boolean,
+      private transformers: MetadataTransformer[]) {
+    for (let transformer of transformers) {
+      if (transformer.connect) {
+        transformer.connect(this);
+      }
+    }
+  }
+
+  getMetadata(sourceFile: ts.SourceFile): ModuleMetadata|undefined {
+    if (this.metadataCache.has(sourceFile.fileName)) {
+      return this.metadataCache.get(sourceFile.fileName);
+    }
+    let substitute: ValueTransform|undefined = undefined;
+
+    // Only process transformers on modules that are not declaration files.
+    const declarationFile = sourceFile.isDeclarationFile;
+    const moduleFile = ts.isExternalModule(sourceFile);
+    if (!declarationFile && moduleFile) {
+      for (let transform of this.transformers) {
+        const transformSubstitute = transform.start(sourceFile);
+        if (transformSubstitute) {
+          if (substitute) {
+            const previous: ValueTransform = substitute;
+            substitute = (value: MetadataValue, node: ts.Node) =>
+                transformSubstitute(previous(value, node), node);
+          } else {
+            substitute = transformSubstitute;
+          }
+        }
+      }
+    }
+
+    const result = this.collector.getMetadata(sourceFile, this.strict, substitute);
+    this.metadataCache.set(sourceFile.fileName, result);
+    return result;
+  }
+}