Expose Graph object from the delta bundler

Reviewed By: davidaurelio

Differential Revision: D7158629

fbshipit-source-id: bb10ad8449cc8f1566f02568adaaecbc54c76d2e

packages/metro/src/DeltaBundler/DeltaCalculator.js

@@ -21,6 +21,7 @@ import type Bundler from '../Bundler';
 import type {Options as JSTransformerOptions} from '../JSTransformer/worker';
 import type DependencyGraph from '../node-haste/DependencyGraph';
 import type {BundleOptions} from '../shared/types.flow';
+import type {DependencyEdge, DependencyEdges} from './traverseDependencies';
 
 export type DeltaResult = {|
   +modified: Map<string, DependencyEdge>,
@@ -28,7 +29,10 @@ export type DeltaResult = {|
   +reset: boolean,
 |};
 
-import type {DependencyEdge, DependencyEdges} from './traverseDependencies';
+export type Graph = {|
+  dependencies: DependencyEdges,
+  entryFile: string,
+|};
 
 /**
  * This class is in charge of calculating the delta of changed modules that
@@ -46,7 +50,7 @@ class DeltaCalculator extends EventEmitter {
   _deletedFiles: Set<string> = new Set();
   _modifiedFiles: Set<string> = new Set();
 
-  _dependencyEdges: DependencyEdges = new Map();
+  _graph: Graph;
 
   constructor(
     bundler: Bundler,
@@ -59,6 +63,15 @@ class DeltaCalculator extends EventEmitter {
     this._options = options;
     this._dependencyGraph = dependencyGraph;
 
+    const entryFilePath = this._dependencyGraph.getAbsolutePath(
+      this._options.entryFile,
+    );
+
+    this._graph = {
+      dependencies: new Map(),
+      entryFile: entryFilePath,
+    };
+
     this._dependencyGraph
       .getWatcher()
       .on('change', this._handleMultipleFileChanges);
@@ -72,14 +85,15 @@ class DeltaCalculator extends EventEmitter {
       .getWatcher()
       .removeListener('change', this._handleMultipleFileChanges);
 
-    this.reset();
-  }
+    this.removeAllListeners();
 
-  reset() {
     // Clean up all the cache data structures to deallocate memory.
+    this._graph = {
+      dependencies: new Map(),
+      entryFile: this._options.entryFile,
+    };
     this._modifiedFiles = new Set();
     this._deletedFiles = new Set();
-    this._dependencyEdges = new Map();
   }
 
   /**
@@ -111,7 +125,7 @@ class DeltaCalculator extends EventEmitter {
 
     let result;
 
-    const numDependencies = this._dependencyEdges.size;
+    const numDependencies = this._graph.dependencies.size;
 
     try {
       result = await this._currentBuildPromise;
@@ -126,8 +140,8 @@ class DeltaCalculator extends EventEmitter {
       // If after an error the number of edges has changed, we could be in
       // a weird state. As a safe net we clean the dependency edges to force
       // a clean traversal of the graph next time.
-      if (this._dependencyEdges.size !== numDependencies) {
-        this._dependencyEdges = new Map();
+      if (this._graph.dependencies.size !== numDependencies) {
+        this._graph.dependencies = new Map();
       }
 
       throw error;
@@ -137,13 +151,13 @@ class DeltaCalculator extends EventEmitter {
 
     // Return all the modules if the client requested a reset delta.
     if (reset) {
+      this._graph.dependencies = reorderDependencies(
+        this._graph.dependencies.get(this._graph.entryFile),
+        this._graph.dependencies,
+      );
+
       return {
-        modified: reorderDependencies(
-          this._dependencyEdges.get(
-            this._dependencyGraph.getAbsolutePath(this._options.entryFile),
-          ),
-          this._dependencyEdges,
-        ),
+        modified: this._graph.dependencies,
         deleted: new Set(),
         reset: true,
       };
@@ -207,12 +221,12 @@ class DeltaCalculator extends EventEmitter {
   }
 
   /**
-   * Returns all the dependency edges from the graph. Each edge contains the
+   * Returns the graph with all the dependency edges. Each edge contains the
    * needed information to do the traversing (dependencies, inverseDependencies)
    * plus some metadata.
    */
-  getDependencyEdges(): DependencyEdges {
-    return this._dependencyEdges;
+  getGraph(): Graph {
+    return this._graph;
   }
 
   _handleMultipleFileChanges = ({eventsQueue}) => {
@@ -250,16 +264,12 @@ class DeltaCalculator extends EventEmitter {
   ): Promise<DeltaResult> {
     const transformerOptions = await this.getTransformerOptions();
 
-    if (!this._dependencyEdges.size) {
-      const path = this._dependencyGraph.getAbsolutePath(
-        this._options.entryFile,
-      );
-
+    if (!this._graph.dependencies.size) {
       const {added} = await initialTraverseDependencies(
-        path,
+        this._graph.entryFile,
         this._dependencyGraph,
         transformerOptions,
-        this._dependencyEdges,
+        this._graph.dependencies,
         this._options.onProgress || undefined,
       );
 
@@ -273,7 +283,7 @@ class DeltaCalculator extends EventEmitter {
     // If a file has been deleted, we want to invalidate any other file that
     // depends on it, so we can process it and correctly return an error.
     deletedFiles.forEach(filePath => {
-      const edge = this._dependencyEdges.get(filePath);
+      const edge = this._graph.dependencies.get(filePath);
 
       if (edge) {
         edge.inverseDependencies.forEach(path => modifiedFiles.add(path));
@@ -282,7 +292,7 @@ class DeltaCalculator extends EventEmitter {
 
     // We only want to process files that are in the bundle.
     const modifiedDependencies = Array.from(modifiedFiles).filter(filePath =>
-      this._dependencyEdges.has(filePath),
+      this._graph.dependencies.has(filePath),
     );
 
     // No changes happened. Return empty delta.
@@ -294,7 +304,7 @@ class DeltaCalculator extends EventEmitter {
       modifiedDependencies,
       this._dependencyGraph,
       transformerOptions,
-      this._dependencyEdges,
+      this._graph.dependencies,
       this._options.onProgress || undefined,
     );
 

packages/metro/src/DeltaBundler/DeltaTransformer.js

@@ -154,7 +154,7 @@ class DeltaTransformer extends EventEmitter {
    * transitive dependencies of any given file within the dependency graph.
    **/
   async getDependenciesFn(): Promise<(string) => Set<string>> {
-    if (!this._deltaCalculator.getDependencyEdges().size) {
+    if (!this._deltaCalculator.getGraph().dependencies.size) {
       // If by any means the dependency graph has not been initialized, call
       // getDelta() to initialize it.
       await this._getDelta({reset: false});
@@ -168,16 +168,17 @@ class DeltaTransformer extends EventEmitter {
    * transitive dependencies of any given file within the dependency graph.
    **/
   async getInverseDependencies(): Promise<Map<number, $ReadOnlyArray<number>>> {
-    if (!this._deltaCalculator.getDependencyEdges().size) {
+    const graph = this._deltaCalculator.getGraph();
+
+    if (!graph.dependencies.size) {
       // If by any means the dependency graph has not been initialized, call
       // getDelta() to initialize it.
       await this._getDelta({reset: false});
     }
 
-    const dependencyEdges = this._deltaCalculator.getDependencyEdges();
     const output = new Map();
 
-    for (const [path, {inverseDependencies}] of dependencyEdges.entries()) {
+    for (const [path, {inverseDependencies}] of graph.dependencies.entries()) {
       output.set(
         this._getModuleId(path),
         Array.from(inverseDependencies).map(dep => this._getModuleId(dep)),
@@ -226,14 +227,14 @@ class DeltaTransformer extends EventEmitter {
     const {modified, deleted, reset} = await this._deltaCalculator.getDelta({
       reset: resetDelta,
     });
+    const graph = this._deltaCalculator.getGraph();
 
     const transformerOptions = await this._deltaCalculator.getTransformerOptions();
-    const dependencyEdges = this._deltaCalculator.getDependencyEdges();
 
     // Return the source code that gets prepended to all the modules. This
     // contains polyfills and startup code (like the require() implementation).
     const prependSources = reset
-      ? await this._getPrepend(transformerOptions, dependencyEdges)
+      ? await this._getPrepend(transformerOptions, graph.dependencies)
       : new Map();
 
     // Precalculate all module ids sequentially. We do this to be sure that the
@@ -245,7 +246,7 @@ class DeltaTransformer extends EventEmitter {
     const modifiedDelta = await this._transformModules(
       modules,
       transformerOptions,
-      dependencyEdges,
+      graph.dependencies,
     );
 
     deleted.forEach(id => {
@@ -255,7 +256,7 @@ class DeltaTransformer extends EventEmitter {
     // Return the source code that gets appended to all the modules. This
     // contains the require() calls to startup the execution of the modules.
     const appendSources = reset
-      ? await this._getAppend(dependencyEdges)
+      ? await this._getAppend(graph.dependencies)
       : new Map();
 
     // generate a random
@@ -271,11 +272,9 @@ class DeltaTransformer extends EventEmitter {
   }
 
   _getDependencies = (path: string): Set<string> => {
-    const dependencies = this._getDeps(
-      path,
-      this._deltaCalculator.getDependencyEdges(),
-      new Set(),
-    );
+    const graph = this._deltaCalculator.getGraph();
+
+    const dependencies = this._getDeps(path, graph.dependencies, new Set());
 
     // Remove the main entry point, since this method only returns the
     // dependencies.

packages/metro/src/DeltaBundler/__tests__/DeltaCalculator-test.js

@@ -385,6 +385,17 @@ describe('DeltaCalculator', () => {
     expect(traverseDependencies.mock.calls[0][0]).toEqual(['/foo']);
   });
 
+  it('should not mutate an existing graph when calling end()', async () => {
+    await deltaCalculator.getDelta({reset: false});
+    const graph = deltaCalculator.getGraph();
+
+    const numDependencies = graph.dependencies.size;
+
+    deltaCalculator.end();
+
+    expect(graph.dependencies.size).toEqual(numDependencies);
+  });
+
   describe('getTransformerOptions()', () => {
     it('should calculate the transform options correctly', async () => {
       expect(await deltaCalculator.getTransformerOptions()).toEqual({

packages/metro/src/__fixtures__/getTransformOptions.js

@@ -32,6 +32,9 @@ async function getTransformOptions(): Promise<JSTransformerOptions> {
     getWatcher() {
       return {on() {}};
     },
+    getAbsolutePath(path) {
+      return '/' + path;
+    },
   };
   const options = {
     assetPlugins: [],