Various bug fixes and improvements.

- Exposed primary constructor in initializer and added more convenience functions
- Fix: error handler not being passed through when changing server
- New: warn developer when a critical error occurs but is not covered with a callback
- New: Typed exceptions for missing birthday or viewingKey values during initialization
- New: updated default server for checkpoint tool

src/main/java/cash/z/ecc/android/sdk/Initializer.kt

@@ -13,7 +13,7 @@ import java.io.File
 /**
  * Simplified Initializer focused on starting from a ViewingKey.
  */
-class Initializer private constructor(appContext: Context, builder: Builder):  SdkSynchronizer.SdkInitializer {
+class Initializer constructor(appContext: Context, builder: Builder):  SdkSynchronizer.SdkInitializer {
     override val context = appContext.applicationContext
     override val rustBackend: RustBackend
     override val alias: String
@@ -255,8 +255,34 @@ class Initializer private constructor(appContext: Context, builder: Builder):  S
             importedWalletBirthday(birthdayHeight)
         }
 
-        fun new(seed: ByteArray) {
+        fun import(
+            viewingKey: String,
+            birthdayHeight: Int,
+            host: String = ZcashSdk.DEFAULT_LIGHTWALLETD_HOST,
+            port: Int = ZcashSdk.DEFAULT_LIGHTWALLETD_PORT
+        ) {
+            setViewingKeys(viewingKey)
+            server(host, port)
+            this.birthdayHeight = birthdayHeight
+        }
+
+        fun new(
+            seed: ByteArray,
+            host: String = ZcashSdk.DEFAULT_LIGHTWALLETD_HOST,
+            port: Int = ZcashSdk.DEFAULT_LIGHTWALLETD_PORT
+        ) {
             setSeed(seed)
+            server(host, port)
+            newWalletBirthday()
+        }
+
+        fun new(
+            viewingKey: String,
+            host: String = ZcashSdk.DEFAULT_LIGHTWALLETD_HOST,
+            port: Int = ZcashSdk.DEFAULT_LIGHTWALLETD_PORT
+        ) {
+            setViewingKeys(viewingKey)
+            server(host, port)
             newWalletBirthday()
         }
 

src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt

@@ -231,7 +231,10 @@ class SdkSynchronizer internal constructor(
     override suspend fun changeServer(host: String, port: Int, errorHandler: (Throwable) -> Unit) {
         val info =
             (processor.downloader.lightWalletService as LightWalletGrpcService).connectionInfo
-        processor.downloader.changeService(LightWalletGrpcService(info.appContext, host, port))
+        processor.downloader.changeService(
+            LightWalletGrpcService(info.appContext, host, port),
+            errorHandler
+        )
     }
 
 
@@ -305,6 +308,15 @@ class SdkSynchronizer internal constructor(
         if (error.cause?.cause != null) twig("******** caused by ${error.cause?.cause}")
         twig("********")
 
+        if (onCriticalErrorHandler == null) {
+            twig(
+                "WARNING: a critical error occurred but no callback is registered to be notified " +
+                        "of critical errors! THIS IS PROBABLY A MISTAKE. To respond to these " +
+                        "errors (perhaps to update the UI or alert the user) set " +
+                        "synchronizer.onCriticalErrorHandler to a non-null value."
+            )
+        }
+
         onCriticalErrorHandler?.invoke(error)
     }
 

src/main/java/cash/z/ecc/android/sdk/block/CompactBlockDownloader.kt

@@ -1,7 +1,6 @@
 package cash.z.ecc.android.sdk.block
 
 import cash.z.ecc.android.sdk.exception.LightWalletException
-import cash.z.ecc.android.sdk.ext.tryCatchWith
 import cash.z.ecc.android.sdk.ext.tryWarn
 import cash.z.ecc.android.sdk.service.LightWalletService
 import cash.z.wallet.sdk.rpc.Service

src/main/java/cash/z/ecc/android/sdk/exception/Exceptions.kt

@@ -80,11 +80,6 @@ sealed class BirthdayException(message: String, cause: Throwable? = null) : SdkE
     class MissingBirthdayFilesException(directory: String) : BirthdayException(
         "Cannot initialize wallet because no birthday files were found in the $directory directory."
     )
-    class MissingBirthdayException(val alias: String) : BirthdayException(
-        "Failed to initialize wallet with alias=$alias because its birthday could not be found." +
-                "  Verify the alias or perhaps a new wallet should be created, instead."
-    )
-
     class ExactBirthdayNotFoundException(height: Int, nearestMatch: Int? = null): BirthdayException(
             "Unable to find birthday that exactly matches $height.${
                 if (nearestMatch != null) 
@@ -108,6 +103,18 @@ sealed class InitializerException(message: String, cause: Throwable? = null) :
     class FalseStart(cause: Throwable?) : InitializerException("Failed to initialize accounts due to: $cause", cause)
     class AlreadyInitializedException(cause: Throwable, dbPath: String) : InitializerException("Failed to initialize the blocks table" +
             " because it already exists in $dbPath", cause)
+    object MissingBirthdayException : InitializerException(
+        "Expected a birthday for this wallet but failed to find one. This usually means that " +
+                "wallet setup did not happen correctly. A workaround might be to interpret the " +
+                "birthday,  based on the contents of the wallet data but it is probably better " +
+                "not to mask this error because the root issue should be addressed."
+    )
+    object MissingViewingKeyException : InitializerException(
+        "Expected a viewingKey for this wallet but failed to find one. This usually means that " +
+                "wallet setup happened incorrectly. A workaround might be to derive the " +
+                "viewingKey from the seed or seedPhrase, if they exist, but it is probably " +
+                "better not to mask this error because the root issue should be addressed."
+    )
     object DatabasePathException :
         InitializerException("Critical failure to locate path for storing databases. Perhaps this" +
                 " device prevents apps from storing data? We cannot initialize the wallet unless" +

src/main/rust/bin/update_sapling_tree.rs

@@ -13,14 +13,14 @@ use zcash_primitives::{merkle_tree::CommitmentTree, sapling::Node};
 #[cfg(feature = "mainnet")]
 const START_HEIGHT: u64 = 419200;
 #[cfg(feature = "mainnet")]
-const LIGHTWALLETD_HOST: &str = "lightwalletd.z.cash";
+const LIGHTWALLETD_HOST: &str = "lightwalletd.electriccoin.co";
 #[cfg(feature = "mainnet")]
 const NETWORK: &str = "mainnet";
 
 #[cfg(not(feature = "mainnet"))]
 const START_HEIGHT: u64 = 280000;
 #[cfg(not(feature = "mainnet"))]
-const LIGHTWALLETD_HOST: &str = "lightwalletd.testnet.z.cash";
+const LIGHTWALLETD_HOST: &str = "lightwalletd.testnet.electriccoin.co";
 #[cfg(not(feature = "mainnet"))]
 const NETWORK: &str = "testnet";
 

src/main/rust/lib.rs

@@ -711,9 +711,9 @@ pub unsafe extern "C" fn Java_cash_z_ecc_android_sdk_tool_DerivationTool_deriveT
         let secp = Secp256k1::new();
         let pk = PublicKey::from_secret_key(&secp, &address_sk);
         let mut hash160 = ripemd160::Ripemd160::new();
-        hash160.input(Sha256::digest(&pk.serialize()[..].to_vec()));
+        hash160.update(Sha256::digest(&pk.serialize()[..].to_vec()));
         let address_string = hash160
-            .result()
+            .finalize()
             .to_base58check(&B58_PUBKEY_ADDRESS_PREFIX, &[]);
 
         let output = env