From 2751306a85fd1079453f181e2cf4539cbef0af24 Mon Sep 17 00:00:00 2001
From: Milan Cerovsky <milan@z.cash>
Date: Wed, 14 Aug 2024 09:42:17 +0200
Subject: [PATCH 1/2] Tor initialization and disposal

---
 .../cash/z/ecc/android/sdk/SdkSynchronizer.kt |  1 +
 .../exchange/UsdExchangeRateFetcher.kt        | 42 ++++++++++++-------
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
index c34e5cc2..a2806b0c 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
@@ -370,6 +370,7 @@ class SdkSynchronizer private constructor(
             coroutineScope.launch {
                 Twig.info { "Stopping synchronizer $synchronizerKey…" }
                 processor.stop()
+                fetchExchangeChangeUsd.dispose()
             }
 
         instances[synchronizerKey] = InstanceState.ShuttingDown(shutdownJob)
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
index 4b01b654..98eeb20a 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
@@ -5,33 +5,25 @@ import cash.z.ecc.android.sdk.internal.model.TorClient
 import cash.z.ecc.android.sdk.model.FetchFiatCurrencyResult
 import cash.z.ecc.android.sdk.model.FiatCurrencyConversion
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import kotlinx.datetime.Clock
 import java.io.File
 
-internal class UsdExchangeRateFetcher(private val torDir: File) {
+internal class UsdExchangeRateFetcher(torDir: File) {
+
+    private val torHolder = TorClientHolder(torDir)
+
     @Suppress("TooGenericExceptionCaught", "ReturnCount")
     suspend operator fun invoke(): FetchFiatCurrencyResult {
-        val tor =
-            retry {
-                try {
-                    Twig.info { "[USD] Tor client bootstrap" }
-                    TorClient.new(torDir)
-                } catch (e: Exception) {
-                    Twig.error(e) { "[USD] To client bootstrap failed" }
-                    return FetchFiatCurrencyResult.Error(exception = e)
-                }
-            }
-
         return retry {
             val rate =
                 try {
                     Twig.info { "[USD] Fetch start" }
-                    tor.getExchangeRateUsd()
+                    torHolder().getExchangeRateUsd()
                 } catch (e: Exception) {
                     Twig.error(e) { "[USD] Fetch failed" }
                     return FetchFiatCurrencyResult.Error(e)
-                } finally {
-                    tor.dispose()
                 }
 
             Twig.debug { "[USD] Fetch success: $rate" }
@@ -46,6 +38,10 @@ internal class UsdExchangeRateFetcher(private val torDir: File) {
         }
     }
 
+    suspend fun dispose() {
+        torHolder.dispose()
+    }
+
     /**
      * Retry with geometric order.
      */
@@ -69,3 +65,19 @@ internal class UsdExchangeRateFetcher(private val torDir: File) {
         return block() // last attempt
     }
 }
+
+private class TorClientHolder(private val torDir: File) {
+    private val mutex = Mutex()
+    private var torClient: TorClient? = null
+
+    suspend operator fun invoke(): TorClient = mutex.withLock {
+        if (torClient == null) {
+            torClient = TorClient.new(torDir)
+        }
+        return torClient!!
+    }
+
+    suspend fun dispose() = mutex.withLock {
+        torClient?.dispose()
+    }
+}

From 862c08bb827ab57816b6e39ecf866033b5062f08 Mon Sep 17 00:00:00 2001
From: Milan Cerovsky <milan@z.cash>
Date: Wed, 14 Aug 2024 11:23:32 +0200
Subject: [PATCH 2/2] Code cleanup

---
 .../exchange/UsdExchangeRateFetcher.kt        | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
index 98eeb20a..2fcc520d 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/exchange/UsdExchangeRateFetcher.kt
@@ -11,7 +11,6 @@ import kotlinx.datetime.Clock
 import java.io.File
 
 internal class UsdExchangeRateFetcher(torDir: File) {
-
     private val torHolder = TorClientHolder(torDir)
 
     @Suppress("TooGenericExceptionCaught", "ReturnCount")
@@ -70,14 +69,16 @@ private class TorClientHolder(private val torDir: File) {
     private val mutex = Mutex()
     private var torClient: TorClient? = null
 
-    suspend operator fun invoke(): TorClient = mutex.withLock {
-        if (torClient == null) {
-            torClient = TorClient.new(torDir)
+    suspend operator fun invoke(): TorClient =
+        mutex.withLock {
+            if (torClient == null) {
+                torClient = TorClient.new(torDir)
+            }
+            return torClient!!
         }
-        return torClient!!
-    }
 
-    suspend fun dispose() = mutex.withLock {
-        torClient?.dispose()
-    }
+    suspend fun dispose() =
+        mutex.withLock {
+            torClient?.dispose()
+        }
 }