feat: Android seed gc (#2339)

* feat: gc() when seed reference should be no longser in use to decrease probability to find it in memory

* added gc calls for many other method that are using seed phrase

android/src/main/java/io/parity/signer/domain/storage/SeedRepository.kt

@@ -134,17 +134,20 @@ class SeedRepository(
 			return when (val authResult = authentication.authenticate(activity)) {
 				AuthResult.AuthSuccess -> {
 					addSeedDangerous(seedName, seedPhrase, networksKeys)
+					System.gc()
 					AuthOperationResult.Success
 				}
 
 				AuthResult.AuthError,
 				AuthResult.AuthFailed,
 				AuthResult.AuthUnavailable -> {
+					System.gc()
 					Timber.w(TAG, "auth error - $authResult")
 					AuthOperationResult.AuthFailed(authResult)
 				}
 			}
 		} catch (e: java.lang.Exception) {
+			System.gc()
 			Timber.e(TAG, e.toString())
 			return AuthOperationResult.Error(e)
 		}
@@ -161,6 +164,7 @@ class SeedRepository(
 		} catch (e: ErrorDisplayed) {
 			submitErrorState("error in add seed $e")
 		}
+		System.gc()
 	}
 
 	/**
@@ -200,6 +204,9 @@ class SeedRepository(
 			.filter { it.isNotEmpty() }
 			.joinToString(separator = "\n")
 
+		//Just collect some old seeds
+		System.gc()
+
 		return if (seedPhrases.isNotBlank()) {
 			RepoResult.Success(seedPhrases)
 		} else {

android/src/main/java/io/parity/signer/domain/storage/SeedStorage.kt

@@ -13,7 +13,6 @@ import io.parity.signer.domain.FeatureFlags
 import io.parity.signer.domain.FeatureOption
 import io.parity.signer.domain.backend.OperationResult
 import io.parity.signer.screens.error.ErrorStateDestinationState
-import io.parity.signer.uniffi.ErrorDisplayed
 import io.parity.signer.uniffi.historySeedWasShown
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -145,8 +144,11 @@ class SeedStorage {
 	/**
 	 * @throws UserNotAuthenticatedException
 	 */
-	fun checkIfSeedNameAlreadyExists(seedPhrase: String) =
-		sharedPreferences.all.values.contains(seedPhrase)
+	fun checkIfSeedNameAlreadyExists(seedPhrase: String) : Boolean {
+		val result = sharedPreferences.all.values.contains(seedPhrase)
+		Runtime.getRuntime().gc()
+		return result
+	}
 
 	/**
 	 * @throws UserNotAuthenticatedException

android/src/main/java/io/parity/signer/screens/createderivation/DerivationCreateViewModel.kt

@@ -134,6 +134,7 @@ class DerivationCreateViewModel : ViewModel() {
 					path = path.value,
 					networkKey = selectedNetwork.key
 				)
+				System.gc()
 				when (result) {
 					is OperationResult.Ok -> {
 						Toast.makeText(

android/src/main/java/io/parity/signer/screens/keydetails/KeyDetailsScreenViewModel.kt

@@ -49,6 +49,7 @@ class KeyDetailsScreenViewModel : ViewModel() {
 					seedPhrase = seedResult.result,
 					keyPassword = password,
 				)
+				System.gc()
 				when (secretKeyDetailsQR) {
 					is UniffiResult.Error -> OperationResult.Err(secretKeyDetailsQR.error)
 					is UniffiResult.Success -> {
@@ -96,6 +97,8 @@ class KeyDetailsScreenViewModel : ViewModel() {
 					seedPhrase = seedResult.result,
 					keyPassword = password,
 				)
+				System.gc()
+
 				when (secretKeyDetailsQR) {
 					is UniffiResult.Error -> {
 						if (passwordModel.attempt > 3) {

android/src/main/java/io/parity/signer/screens/scan/ScanViewModel.kt

@@ -233,6 +233,7 @@ class ScanViewModel : ViewModel() {
 			is RepoResult.Success -> {
 				val previewDynDerivations =
 					uniffiInteractor.previewDynamicDerivations(phrases.result, payload)
+				System.gc()
 
 				when (previewDynDerivations) {
 					is UniffiResult.Error -> {
@@ -266,6 +267,7 @@ class ScanViewModel : ViewModel() {
 					uniffiInteractor.signDynamicDerivationsTransactions(
 						phrases.result, payload
 					)
+				System.gc()
 
 				when (dynDerivations) {
 					is UniffiResult.Error -> {
@@ -383,10 +385,12 @@ class ScanViewModel : ViewModel() {
 			}
 
 			is RepoResult.Success -> {
-				scanFlowInteractor.continueSigningTransaction(
+				val result = scanFlowInteractor.continueSigningTransaction(
 					comment,
 					phrases.result,
 				)
+				System.gc()
+				result
 			}
 		}
 	}

android/src/main/java/io/parity/signer/screens/scan/addnetwork/AddedNetworkViewModel.kt

@@ -57,6 +57,7 @@ class AddedNetworkViewModel : ViewModel() {
 							seedName = seedPair.first, seedPhrase = seedPair.second,
 							path = network.pathId, network = network.key,
 						)
+						System.gc()
 					} catch (e: ErrorDisplayed) {
 						result = false
 						submitErrorState("can't create network key for added network, ${e.message}")

android/src/main/java/io/parity/signer/screens/scan/importderivations/ImportDerivedKeysRepository.kt

@@ -35,6 +35,7 @@ class ImportDerivedKeysRepository(
 			seedRepository.getAllSeeds().mapError() ?: return RepoResult.Failure()
 		return try {
 			val filledSeedKeys = populateDerivationsHasPwd(seeds, seedPreviews)
+			System.gc()
 			RepoResult.Success(filledSeedKeys)
 		} catch (e: java.lang.Exception) {
 			RepoResult.Failure(e)

android/src/main/java/io/parity/signer/screens/settings/networks/signspecs/SignSpecsViewModel.kt

@@ -95,6 +95,7 @@ class SignSpecsViewModel : ViewModel() {
 							}
 						}
 					}
+					System.gc()
 				}
 			}
 		}