feat(@angular-devkit/core): implement workspace JSON reader/writer

Author: clydin

packages/angular_devkit/core/BUILD

@@ -33,6 +33,7 @@ ts_library(
         "@npm//@types/node",
         "@npm//@types/source-map",
         "@npm//ajv",
+        "@npm//magic-string",
         # @typings: es2015.core
         # @typings: es2015.symbol.wellknown
         # @typings: es2016.array.include

packages/angular_devkit/core/package.json

@@ -10,6 +10,7 @@
   "dependencies": {
     "ajv": "6.10.0",
     "fast-json-stable-stringify": "2.0.0",
+    "magic-string": "0.25.1",
     "rxjs": "6.4.0",
     "source-map": "0.7.3"
   },

packages/angular_devkit/core/src/workspace/core.ts

@@ -6,8 +6,10 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import { basename, getSystemPath, join, normalize } from '../virtual-fs';
-import { ProjectDefinitionCollection, WorkspaceDefinition } from './definitions';
+import { WorkspaceDefinition } from './definitions';
 import { WorkspaceHost } from './host';
+import { readJsonWorkspace } from './json/reader';
+import { writeJsonWorkspace } from './json/writer';
 
 const formatLookup = new WeakMap<WorkspaceDefinition, WorkspaceFormat>();
 
@@ -45,8 +47,6 @@ export async function readWorkspace(
 
       const potential = getSystemPath(join(directory, name));
       if (await host.isFile(potential)) {
-        // TEMP - remove disable when actual reader is used
-        // tslint:disable-next-line:no-dead-store
         path = potential;
         format = nameFormat;
         found = true;
@@ -70,12 +70,7 @@ export async function readWorkspace(
   let workspace;
   switch (format) {
     case WorkspaceFormat.JSON:
-      // TEMP: remove the following two statements when JSON support is introduced
-      await host.readFile(path);
-      workspace = {
-        extensions: {},
-        projects: new ProjectDefinitionCollection(),
-      };
+      workspace = await readJsonWorkspace(path, host);
       break;
     default:
       throw new Error('Unsupported workspace format.');
@@ -88,8 +83,8 @@ export async function readWorkspace(
 
 export async function writeWorkspace(
   workspace: WorkspaceDefinition,
-  _host: WorkspaceHost,
-  _path?: string,
+  host: WorkspaceHost,
+  path?: string,
   format?: WorkspaceFormat,
 ): Promise<void> {
   if (format === undefined) {
@@ -101,7 +96,7 @@ export async function writeWorkspace(
 
   switch (format) {
     case WorkspaceFormat.JSON:
-      throw new Error('Not Implemented.');
+      return writeJsonWorkspace(workspace, host, path);
     default:
       throw new Error('Unsupported workspace format.');
   }

packages/angular_devkit/core/src/workspace/json/metadata.ts

@@ -0,0 +1,74 @@
+/**
+ * @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 { JsonAstArray, JsonAstKeyValue, JsonAstNode, JsonAstObject, JsonValue } from '../../json';
+import { ProjectDefinition, TargetDefinition, WorkspaceDefinition } from '../definitions';
+
+export const JsonWorkspaceSymbol = Symbol.for('@angular/core:workspace-json');
+
+export interface JsonWorkspaceDefinition extends WorkspaceDefinition {
+  [JsonWorkspaceSymbol]: JsonWorkspaceMetadata;
+}
+
+interface ChangeValues {
+  json: JsonValue;
+  project: ProjectDefinition;
+  target: TargetDefinition;
+  projectcollection: Iterable<[string, ProjectDefinition]>;
+  targetcollection: Iterable<[string, TargetDefinition]>;
+}
+
+export interface JsonChange<T extends keyof ChangeValues = keyof ChangeValues> {
+  // core collections can only be added as they are managed directly by _Collection_ objects
+  op: T extends 'json' | 'project' | 'target' ? 'add' | 'remove' | 'replace' : 'add';
+  path: string;
+  node: JsonAstNode | JsonAstKeyValue;
+  value?: ChangeValues[T];
+  type: T;
+}
+
+export class JsonWorkspaceMetadata {
+  readonly changes: JsonChange[] = [];
+
+  constructor(readonly filePath: string, readonly ast: JsonAstObject, readonly raw: string) { }
+
+  get hasChanges(): boolean {
+    return this.changes.length > 0;
+  }
+
+  get changeCount(): number {
+    return this.changes.length;
+  }
+
+  findChangesForPath(path: string): JsonChange[] {
+    return this.changes.filter(c => c.path === path);
+  }
+
+  addChange<T extends keyof ChangeValues = keyof ChangeValues>(
+    op: 'add' | 'remove' | 'replace',
+    path: string,
+    node: JsonAstArray | JsonAstObject | JsonAstKeyValue,
+    value?: ChangeValues[T],
+    type?: T,
+  ): void {
+    // Remove redundant operations
+    if (op === 'remove' || op === 'replace') {
+      for (let i = this.changes.length - 1; i >= 0; --i) {
+        const currentPath = this.changes[i].path;
+        if (currentPath === path || currentPath.startsWith(path + '/')) {
+          this.changes.splice(i, 1);
+        }
+      }
+    }
+
+    this.changes.push({ op, path, node, value, type: op === 'remove' || !type ? 'json' : type });
+  }
+
+  reset(): void {
+    this.changes.length = 0;
+  }
+}