Update to modify repo in place

Author: samtstern

packages/database/src/api/Database.ts

@@ -36,7 +36,7 @@ export class Database implements FirebaseService {
   INTERNAL: DatabaseInternals;
 
   /** Track if the instance has been used (root or repo accessed) */
-  private instanceUsed_: boolean = false;
+  private instanceStarted_: boolean = false;
 
   /** Backing state for root_ */
   private rootInternal_: Reference;
@@ -70,20 +70,19 @@ export class Database implements FirebaseService {
   }
 
   private get repo_(): Repo {
-    this.instanceUsed_ = true;
+    this.instanceStarted_ = true;
     return this.repoInternal_;
   }
 
   private set repo_(repo: Repo) {
-    if (repo instanceof Repo) {
-      this.root_ = new Reference(repo, Path.Empty);
-    }
-
     this.repoInternal_ = repo;
   }
 
   get root_(): Reference {
-    this.instanceUsed_ = true;
+    if (!this.rootInternal_) {
+      this.rootInternal_ = new Reference(this.repo_, Path.Empty);
+    }
+
     return this.rootInternal_;
   }
 
@@ -104,19 +103,15 @@ export class Database implements FirebaseService {
    * @param port the emulator port (ex: 8080)
    */
   useEmulator(host: string, port: number): void {
-    if (this.instanceUsed_) {
+    if (this.instanceStarted_) {
       fatal(
         'Cannot call useEmulator() after instance has already been initialized.'
       );
       return;
     }
 
-    // Get a new Repo which has the emulator settings applied
-    const manager = RepoManager.getInstance();
-    const oldRepo = this.repo_;
-
-    this.repo_ = manager.cloneRepoForEmulator(oldRepo, host, port);
-    manager.deleteRepo(oldRepo);
+    // Modify the repo to apply emulator settings
+    RepoManager.getInstance().applyEmulatorSettings(this.repoInternal_, host, port);
   }
 
   /**

packages/database/src/core/RepoManager.ts

@@ -88,18 +88,27 @@ export class RepoManager {
   }
 
   /**
-   * Create a new repo based on an old one but pointing to a particular host and port.
+   * Update an existing repo in place to point to a new host/port.
    */
-  cloneRepoForEmulator(repo: Repo, host: string, port: number): Repo {
-    const nodeAdmin = repo.repoInfo_.nodeAdmin;
+  applyEmulatorSettings(repo: Repo, host: string, port: number): void {
     const url = `http://${host}:${port}?ns=${repo.repoInfo_.namespace}`;
+
+    const nodeAdmin = repo.repoInfo_.nodeAdmin;
     const authTokenProvider = nodeAdmin
       ? new EmulatorAdminTokenProvider()
       : repo.authTokenProvider;
 
-    const parsedUrl = parseRepoInfo(url, nodeAdmin);
+    // Before we modify the repo, get the key used in the repo manager
+    const oldRepoKey = repo.repoInfo_.toURLString();
+
+    // Update the repo in-place
+    const { repoInfo } = parseRepoInfo(url, nodeAdmin);
+    repo.repoInfo_ = repoInfo;
+    repo.authTokenProvider = authTokenProvider;
 
-    return this.createRepo(parsedUrl.repoInfo, repo.app, authTokenProvider);
+    // Replace the repomanager cache entry
+    delete this.repos_[repo.app.name][oldRepoKey];
+    this.repos_[repo.app.name][repoInfo.toURLString()] = repo;
   }
 
   /**