RustCrypto: fix ordering of methods (#4230)

* RustCrypto: Move CryptoBackend impl to CryptoBackend impl section

Given there is a `CryptoBackend implementation` section, the methods
implementing CryptoBackend should be there.

* RustCrypto: Fix documentation on dehydration methods

* RustCrypto: reunite `resetKeyBackup` with its helper

A couple of new methods had snuck into the middle.

Author: richvdh

src/rust-crypto/rust-crypto.ts

@@ -309,6 +309,40 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         return;
     }
 
+    /**
+     * Implementation of {@link CryptoBackend#getBackupDecryptor}.
+     */
+    public async getBackupDecryptor(backupInfo: KeyBackupInfo, privKey: ArrayLike<number>): Promise<BackupDecryptor> {
+        if (backupInfo.algorithm != "m.megolm_backup.v1.curve25519-aes-sha2") {
+            throw new Error(`getBackupDecryptor Unsupported algorithm ${backupInfo.algorithm}`);
+        }
+
+        const authData = <Curve25519AuthData>backupInfo.auth_data;
+
+        if (!(privKey instanceof Uint8Array)) {
+            throw new Error(`getBackupDecryptor expects Uint8Array`);
+        }
+
+        const backupDecryptionKey = RustSdkCryptoJs.BackupDecryptionKey.fromBase64(encodeBase64(privKey));
+
+        if (authData.public_key != backupDecryptionKey.megolmV1PublicKey.publicKeyBase64) {
+            throw new Error(`getBackupDecryptor key mismatch error`);
+        }
+
+        return this.backupManager.createBackupDecryptor(backupDecryptionKey);
+    }
+
+    /**
+     * Implementation of {@link CryptoBackend#importBackedUpRoomKeys}.
+     */
+    public async importBackedUpRoomKeys(
+        keys: IMegolmSessionData[],
+        backupVersion: string,
+        opts?: ImportRoomKeysOpts,
+    ): Promise<void> {
+        return await this.backupManager.importBackedUpRoomKeys(keys, backupVersion, opts);
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // CryptoApi implementation
@@ -1166,30 +1200,12 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         this.checkKeyBackupAndEnable();
     }
 
-    /**
-     * Implementation of {@link CryptoApi#importSecretsBundle}.
-     */
-    public async importSecretsBundle(
-        secrets: Parameters<NonNullable<CryptoApi["importSecretsBundle"]>>[0],
-    ): Promise<void> {
-        const secretsBundle = RustSdkCryptoJs.SecretsBundle.from_json(secrets);
-        await this.getOlmMachineOrThrow().importSecretsBundle(secretsBundle); // this method frees the SecretsBundle
-    }
-
-    /**
-     * Implementation of {@link CryptoApi#exportSecretsBundle}.
-     */
-    public async exportsSecretsBundle(): ReturnType<NonNullable<CryptoApi["exportSecretsBundle"]>> {
-        const secretsBundle = await this.getOlmMachineOrThrow().exportSecretsBundle();
-        const secrets = secretsBundle.to_json();
-        secretsBundle.free();
-        return secrets;
-    }
-
     /**
      * Signs the given object with the current device and current identity (if available).
      * As defined in {@link https://spec.matrix.org/v1.8/appendices/#signing-json | Signing JSON}.
      *
+     * Helper for {@link RustCrypto#resetKeyBackup}.
+     *
      * @param obj - The object to sign
      */
     private async signObject<T extends ISignableObject & object>(obj: T): Promise<void> {
@@ -1213,54 +1229,40 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
     }
 
     /**
-     * Implementation of {@link CryptoBackend#getBackupDecryptor}.
+     * Implementation of {@link CryptoApi#isDehydrationSupported}.
      */
-    public async getBackupDecryptor(backupInfo: KeyBackupInfo, privKey: ArrayLike<number>): Promise<BackupDecryptor> {
-        if (backupInfo.algorithm != "m.megolm_backup.v1.curve25519-aes-sha2") {
-            throw new Error(`getBackupDecryptor Unsupported algorithm ${backupInfo.algorithm}`);
-        }
-
-        const authData = <Curve25519AuthData>backupInfo.auth_data;
-
-        if (!(privKey instanceof Uint8Array)) {
-            throw new Error(`getBackupDecryptor expects Uint8Array`);
-        }
-
-        const backupDecryptionKey = RustSdkCryptoJs.BackupDecryptionKey.fromBase64(encodeBase64(privKey));
-
-        if (authData.public_key != backupDecryptionKey.megolmV1PublicKey.publicKeyBase64) {
-            throw new Error(`getBackupDecryptor key mismatch error`);
-        }
-
-        return this.backupManager.createBackupDecryptor(backupDecryptionKey);
+    public async isDehydrationSupported(): Promise<boolean> {
+        return await this.dehydratedDeviceManager.isSupported();
     }
 
     /**
-     * Implementation of {@link CryptoBackend#importBackedUpRoomKeys}.
+     * Implementation of {@link CryptoApi#startDehydration}.
      */
-    public async importBackedUpRoomKeys(
-        keys: IMegolmSessionData[],
-        backupVersion: string,
-        opts?: ImportRoomKeysOpts,
-    ): Promise<void> {
-        return await this.backupManager.importBackedUpRoomKeys(keys, backupVersion, opts);
+    public async startDehydration(createNewKey?: boolean): Promise<void> {
+        if (!(await this.isCrossSigningReady()) || !(await this.isSecretStorageReady())) {
+            throw new Error("Device dehydration requires cross-signing and secret storage to be set up");
+        }
+        return await this.dehydratedDeviceManager.start(createNewKey);
     }
 
     /**
-     * Implementation of {@link CryptoBackend#isDehydrationSupported}.
+     * Implementation of {@link CryptoApi#importSecretsBundle}.
      */
-    public async isDehydrationSupported(): Promise<boolean> {
-        return await this.dehydratedDeviceManager.isSupported();
+    public async importSecretsBundle(
+        secrets: Parameters<NonNullable<CryptoApi["importSecretsBundle"]>>[0],
+    ): Promise<void> {
+        const secretsBundle = RustSdkCryptoJs.SecretsBundle.from_json(secrets);
+        await this.getOlmMachineOrThrow().importSecretsBundle(secretsBundle); // this method frees the SecretsBundle
     }
 
     /**
-     * Implementation of {@link CryptoBackend#startDehydration}.
+     * Implementation of {@link CryptoApi#exportSecretsBundle}.
      */
-    public async startDehydration(createNewKey?: boolean): Promise<void> {
-        if (!(await this.isCrossSigningReady()) || !(await this.isSecretStorageReady())) {
-            throw new Error("Device dehydration requires cross-signing and secret storage to be set up");
-        }
-        return await this.dehydratedDeviceManager.start(createNewKey);
+    public async exportsSecretsBundle(): ReturnType<NonNullable<CryptoApi["exportSecretsBundle"]>> {
+        const secretsBundle = await this.getOlmMachineOrThrow().exportSecretsBundle();
+        const secrets = secretsBundle.to_json();
+        secretsBundle.free();
+        return secrets;
     }
 
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////