Simplify error handling

app/src/main/java/gq/kirmanak/mealient/data/auth/impl/AuthDataSourceImpl.kt

@@ -2,11 +2,12 @@ package gq.kirmanak.mealient.data.auth.impl
 
 import gq.kirmanak.mealient.data.auth.AuthDataSource
 import gq.kirmanak.mealient.data.network.ErrorDetail
-import gq.kirmanak.mealient.data.network.NetworkError.*
+import gq.kirmanak.mealient.data.network.NetworkError.NotMealie
+import gq.kirmanak.mealient.data.network.NetworkError.Unauthorized
 import gq.kirmanak.mealient.data.network.ServiceFactory
 import gq.kirmanak.mealient.extensions.decodeErrorBodyOrNull
-import kotlinx.coroutines.CancellationException
+import gq.kirmanak.mealient.extensions.mapToNetworkError
-import kotlinx.serialization.SerializationException
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import kotlinx.serialization.json.Json
 import retrofit2.HttpException
 import retrofit2.Response
@@ -22,12 +23,7 @@ class AuthDataSourceImpl @Inject constructor(
 
     override suspend fun authenticate(username: String, password: String): String {
         Timber.v("authenticate() called with: username = $username, password = $password")
-        val authService = try {
+        val authService = authServiceFactory.provideService()
-            authServiceFactory.provideService()
-        } catch (e: Exception) {
-            Timber.e(e, "authenticate: can't create Retrofit service")
-            throw MalformedUrl(e)
-        }
         val response = sendRequest(authService, username, password)
         val accessToken = parseToken(response)
         Timber.v("authenticate() returned: $accessToken")
@@ -38,14 +34,11 @@ class AuthDataSourceImpl @Inject constructor(
         authService: AuthService,
         username: String,
         password: String
-    ): Response<GetTokenResponse> = try {
+    ): Response<GetTokenResponse> = runCatchingExceptCancel {
         authService.getToken(username, password)
-    } catch (e: Throwable) {
+    }.getOrElse {
-        throw when (e) {
+        Timber.e(it, "sendRequest: can't request token")
-            is CancellationException -> e
+        throw it.mapToNetworkError()
-            is SerializationException -> NotMealie(e)
-            else -> NoServerConnection(e)
-        }
     }
 
     private fun parseToken(

app/src/main/java/gq/kirmanak/mealient/data/baseurl/VersionDataSourceImpl.kt

@@ -1,10 +1,9 @@
 package gq.kirmanak.mealient.data.baseurl
 
-import gq.kirmanak.mealient.data.network.NetworkError
 import gq.kirmanak.mealient.data.network.ServiceFactory
+import gq.kirmanak.mealient.extensions.mapToNetworkError
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import gq.kirmanak.mealient.extensions.versionInfo
-import kotlinx.serialization.SerializationException
-import retrofit2.HttpException
 import timber.log.Timber
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -17,21 +16,12 @@ class VersionDataSourceImpl @Inject constructor(
     override suspend fun getVersionInfo(baseUrl: String): VersionInfo {
         Timber.v("getVersionInfo() called with: baseUrl = $baseUrl")
 
-        val service = try {
+        val service = serviceFactory.provideService(baseUrl)
-            serviceFactory.provideService(baseUrl)
+        val response = runCatchingExceptCancel {
-        } catch (e: Exception) {
-            Timber.e(e, "getVersionInfo: can't create service")
-            throw NetworkError.MalformedUrl(e)
-        }
-
-        val response = try {
             service.getVersion()
-        } catch (e: Exception) {
+        }.getOrElse {
-            Timber.e(e, "getVersionInfo: can't request version")
+            Timber.e(it, "getVersionInfo: can't request version")
-            when (e) {
+            throw it.mapToNetworkError()
-                is HttpException, is SerializationException -> throw NetworkError.NotMealie(e)
-                else -> throw NetworkError.NoServerConnection(e)
-            }
         }
 
         return response.versionInfo()

app/src/main/java/gq/kirmanak/mealient/data/network/RetrofitServiceFactory.kt

@@ -1,6 +1,7 @@
 package gq.kirmanak.mealient.data.network
 
 import gq.kirmanak.mealient.data.baseurl.BaseURLStorage
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import timber.log.Timber
 
 inline fun <reified T> RetrofitBuilder.createServiceFactory(baseURLStorage: BaseURLStorage) =
@@ -14,10 +15,13 @@ class RetrofitServiceFactory<T>(
 
     private val cache: MutableMap<String, T> = mutableMapOf()
 
-    override suspend fun provideService(baseUrl: String?): T {
+    override suspend fun provideService(baseUrl: String?): T = runCatchingExceptCancel {
         Timber.v("provideService() called with: baseUrl = $baseUrl, class = ${serviceClass.simpleName}")
         val url = baseUrl ?: baseURLStorage.requireBaseURL()
-        return synchronized(cache) { cache[url] ?: createService(url, serviceClass) }
+        synchronized(cache) { cache[url] ?: createService(url, serviceClass) }
+    }.getOrElse {
+        Timber.e(it, "provideService: can't provide service for $baseUrl")
+        throw NetworkError.MalformedUrl(it)
     }
 
     private fun createService(url: String, serviceClass: Class<T>): T {

app/src/main/java/gq/kirmanak/mealient/data/recipes/impl/RecipeRepoImpl.kt

@@ -8,7 +8,7 @@ import gq.kirmanak.mealient.data.recipes.RecipeRepo
 import gq.kirmanak.mealient.data.recipes.db.RecipeStorage
 import gq.kirmanak.mealient.data.recipes.db.entity.RecipeSummaryEntity
 import gq.kirmanak.mealient.data.recipes.network.RecipeDataSource
-import kotlinx.coroutines.CancellationException
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import timber.log.Timber
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -39,12 +39,10 @@ class RecipeRepoImpl @Inject constructor(
     override suspend fun loadRecipeInfo(recipeId: Long, recipeSlug: String): FullRecipeInfo {
         Timber.v("loadRecipeInfo() called with: recipeId = $recipeId, recipeSlug = $recipeSlug")
 
-        try {
+        runCatchingExceptCancel {
             storage.saveRecipeInfo(dataSource.requestRecipeInfo(recipeSlug))
-        } catch (e: CancellationException) {
+        }.onFailure {
-            throw e
+            Timber.e(it, "loadRecipeInfo: can't update full recipe info")
-        } catch (e: Throwable) {
-            Timber.e(e, "loadRecipeInfo: can't update full recipe info")
         }
 
         return storage.queryRecipeInfo(recipeId)

app/src/main/java/gq/kirmanak/mealient/data/recipes/impl/RecipesRemoteMediator.kt

@@ -7,7 +7,7 @@ import androidx.paging.LoadType.REFRESH
 import gq.kirmanak.mealient.data.recipes.db.RecipeStorage
 import gq.kirmanak.mealient.data.recipes.db.entity.RecipeSummaryEntity
 import gq.kirmanak.mealient.data.recipes.network.RecipeDataSource
-import kotlinx.coroutines.CancellationException
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import timber.log.Timber
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -37,16 +37,14 @@ class RecipesRemoteMediator @Inject constructor(
         val start = if (loadType == REFRESH) 0 else lastRequestEnd
         val limit = if (loadType == REFRESH) state.config.initialLoadSize else state.config.pageSize
 
-        val count: Int = try {
+        val count: Int = runCatchingExceptCancel {
             val recipes = network.requestRecipes(start, limit)
             if (loadType == REFRESH) storage.refreshAll(recipes)
             else storage.saveRecipes(recipes)
             recipes.size
-        } catch (e: CancellationException) {
+        }.getOrElse {
-            throw e
+            Timber.e(it, "load: can't load recipes")
-        } catch (e: Throwable) {
+            return MediatorResult.Error(it)
-            Timber.e(e, "Can't load recipes")
-            return MediatorResult.Error(e)
         }
 
         // After something is inserted into DB the paging sources have to be invalidated

app/src/main/java/gq/kirmanak/mealient/extensions/CoroutineExtensions.kt

@@ -0,0 +1,15 @@
+package gq.kirmanak.mealient.extensions
+
+import kotlinx.coroutines.CancellationException
+
+/**
+ * Like [runCatching] but rethrows [CancellationException] to support
+ * cancellation of coroutines.
+ */
+inline fun <T> runCatchingExceptCancel(block: () -> T): Result<T> = try {
+    Result.success(block())
+} catch (e: CancellationException) {
+    throw e
+} catch (e: Throwable) {
+    Result.failure(e)
+}

app/src/main/java/gq/kirmanak/mealient/extensions/NetworkExtensions.kt

@@ -1,8 +1,11 @@
 package gq.kirmanak.mealient.extensions
 
+import gq.kirmanak.mealient.data.network.NetworkError
 import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerializationException
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.decodeFromStream
+import retrofit2.HttpException
 import retrofit2.Response
 import timber.log.Timber
 import java.io.InputStream
@@ -16,3 +19,7 @@ inline fun <reified T> Json.decodeFromStreamOrNull(stream: InputStream): T? =
         .onFailure { Timber.e(it, "decodeFromStreamOrNull: can't decode") }
         .getOrNull()
 
+fun Throwable.mapToNetworkError(): NetworkError = when (this) {
+    is HttpException, is SerializationException -> NetworkError.NotMealie(this)
+    else -> NetworkError.NoServerConnection(this)
+}

app/src/main/java/gq/kirmanak/mealient/ui/auth/AuthenticationViewModel.kt

@@ -6,6 +6,7 @@ import androidx.lifecycle.asLiveData
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import gq.kirmanak.mealient.data.auth.AuthRepo
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.combine
@@ -40,7 +41,7 @@ class AuthenticationViewModel @Inject constructor(
         }
     }
 
-    suspend fun authenticate(username: String, password: String): Result<Unit> = runCatching {
+    suspend fun authenticate(username: String, password: String) = runCatchingExceptCancel {
         authRepo.authenticate(username, password)
     }.onFailure {
         Timber.e(it, "authenticate: can't authenticate")

app/src/main/java/gq/kirmanak/mealient/ui/recipes/info/RecipeInfoViewModel.kt

@@ -9,6 +9,7 @@ import dagger.hilt.android.lifecycle.HiltViewModel
 import gq.kirmanak.mealient.data.recipes.RecipeImageLoader
 import gq.kirmanak.mealient.data.recipes.RecipeRepo
 import gq.kirmanak.mealient.data.recipes.impl.FullRecipeInfo
+import gq.kirmanak.mealient.extensions.runCatchingExceptCancel
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
@@ -41,7 +42,7 @@ constructor(
         recipeIngredientsAdapter.submitList(null)
         recipeInstructionsAdapter.submitList(null)
         viewModelScope.launch {
-            runCatching { recipeRepo.loadRecipeInfo(recipeId, recipeSlug) }
+            runCatchingExceptCancel { recipeRepo.loadRecipeInfo(recipeId, recipeSlug) }
                 .onSuccess {
                     Timber.d("loadRecipeInfo: received recipe info = $it")
                     _recipeInfo.value = it

app/src/test/java/gq/kirmanak/mealient/data/auth/impl/AuthDataSourceImplTest.kt

@@ -71,7 +71,7 @@ class AuthDataSourceImplTest {
 
     @Test(expected = MalformedUrl::class)
     fun `when authenticate and provideService throws then MalformedUrl`() = runTest {
-        coEvery { authServiceFactory.provideService() } throws RuntimeException()
+        coEvery { authServiceFactory.provideService() } throws MalformedUrl(RuntimeException())
         callAuthenticate()
     }
 

app/src/test/java/gq/kirmanak/mealient/data/baseurl/VersionDataSourceImplTest.kt

@@ -36,7 +36,9 @@ class VersionDataSourceImplTest {
 
     @Test(expected = NetworkError.MalformedUrl::class)
     fun `when getVersionInfo and provideService throws then MalformedUrl`() = runTest {
-        coEvery { versionServiceFactory.provideService(eq(TEST_BASE_URL)) } throws RuntimeException()
+        coEvery {
+            versionServiceFactory.provideService(eq(TEST_BASE_URL))
+        } throws NetworkError.MalformedUrl(RuntimeException())
         subject.getVersionInfo(TEST_BASE_URL)
     }