Merge pull request #7349 from thunderbird/folder_fetcher

Add `FolderFetcher` interface

mail/common/src/main/java/com/fsck/k9/mail/folders/FolderFetcher.kt

@@ -0,0 +1,16 @@
+package com.fsck.k9.mail.folders
+
+import com.fsck.k9.mail.ServerSettings
+import com.fsck.k9.mail.oauth.AuthStateStorage
+
+/**
+ * Fetches the list of folders from a server.
+ *
+ * @throws FolderFetcherException in case of an error
+ */
+fun interface FolderFetcher {
+    fun getFolders(
+        serverSettings: ServerSettings,
+        authStateStorage: AuthStateStorage?,
+    ): List<RemoteFolder>
+}

mail/common/src/main/java/com/fsck/k9/mail/folders/FolderFetcherException.kt

@@ -0,0 +1,9 @@
+package com.fsck.k9.mail.folders
+
+/**
+ * Thrown by [FolderFetcher] in case of an error.
+ */
+class FolderFetcherException(
+    cause: Throwable,
+    val messageFromServer: String? = null,
+) : RuntimeException(cause.message, cause)

mail/common/src/main/java/com/fsck/k9/mail/folders/FolderServerId.kt

@@ -0,0 +1,4 @@
+package com.fsck.k9.mail.folders
+
+@JvmInline
+value class FolderServerId(val serverId: String)

mail/common/src/main/java/com/fsck/k9/mail/folders/RemoteFolder.kt

@@ -0,0 +1,9 @@
+package com.fsck.k9.mail.folders
+
+import com.fsck.k9.mail.FolderType
+
+data class RemoteFolder(
+    val serverId: FolderServerId,
+    val displayName: String,
+    val type: FolderType,
+)

mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/ImapFolderFetcher.kt

@@ -0,0 +1,77 @@
+package com.fsck.k9.mail.store.imap
+
+import com.fsck.k9.mail.AuthenticationFailedException
+import com.fsck.k9.mail.ServerSettings
+import com.fsck.k9.mail.folders.FolderFetcher
+import com.fsck.k9.mail.folders.FolderFetcherException
+import com.fsck.k9.mail.folders.FolderServerId
+import com.fsck.k9.mail.folders.RemoteFolder
+import com.fsck.k9.mail.oauth.AuthStateStorage
+import com.fsck.k9.mail.oauth.OAuth2TokenProvider
+import com.fsck.k9.mail.oauth.OAuth2TokenProviderFactory
+import com.fsck.k9.mail.ssl.TrustedSocketFactory
+
+/**
+ * Fetches the list of folders from an IMAP server.
+ */
+class ImapFolderFetcher internal constructor(
+    private val trustedSocketFactory: TrustedSocketFactory,
+    private val oAuth2TokenProviderFactory: OAuth2TokenProviderFactory?,
+    private val clientIdAppName: String,
+    private val clientIdAppVersion: String,
+    private val imapStoreFactory: ImapStoreFactory,
+) : FolderFetcher {
+    constructor(
+        trustedSocketFactory: TrustedSocketFactory,
+        oAuth2TokenProviderFactory: OAuth2TokenProviderFactory?,
+        clientIdAppName: String,
+        clientIdAppVersion: String,
+    ) : this(
+        trustedSocketFactory,
+        oAuth2TokenProviderFactory,
+        clientIdAppName,
+        clientIdAppVersion,
+        imapStoreFactory = ImapStore.Companion,
+    )
+
+    @Suppress("TooGenericExceptionCaught")
+    override fun getFolders(serverSettings: ServerSettings, authStateStorage: AuthStateStorage?): List<RemoteFolder> {
+        require(serverSettings.type == "imap")
+
+        val config = object : ImapStoreConfig {
+            override val logLabel = "folder-fetcher"
+            override fun isSubscribedFoldersOnly() = false
+            override fun clientId() = ImapClientId(appName = clientIdAppName, appVersion = clientIdAppVersion)
+        }
+        val oAuth2TokenProvider = createOAuth2TokenProviderOrNull(authStateStorage)
+        val store = imapStoreFactory.create(serverSettings, config, trustedSocketFactory, oAuth2TokenProvider)
+
+        return try {
+            store.getFolders()
+                .asSequence()
+                .filterNot { it.oldServerId == null }
+                .map { folder ->
+                    RemoteFolder(
+                        serverId = FolderServerId(folder.oldServerId!!),
+                        displayName = folder.name,
+                        type = folder.type,
+                    )
+                }
+                .toList()
+        } catch (e: AuthenticationFailedException) {
+            throw FolderFetcherException(messageFromServer = e.messageFromServer, cause = e)
+        } catch (e: NegativeImapResponseException) {
+            throw FolderFetcherException(messageFromServer = e.responseText, cause = e)
+        } catch (e: Exception) {
+            throw FolderFetcherException(cause = e)
+        } finally {
+            store.closeAllConnections()
+        }
+    }
+
+    private fun createOAuth2TokenProviderOrNull(authStateStorage: AuthStateStorage?): OAuth2TokenProvider? {
+        return authStateStorage?.let {
+            oAuth2TokenProviderFactory?.create(it)
+        }
+    }
+}

mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/ImapStore.kt

@@ -16,8 +16,8 @@ interface ImapStore {
 
     fun closeAllConnections()
 
-    companion object {
-        fun create(
+    companion object : ImapStoreFactory {
+        override fun create(
             serverSettings: ServerSettings,
             config: ImapStoreConfig,
             trustedSocketFactory: TrustedSocketFactory,

mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/ImapStoreFactory.kt

@@ -0,0 +1,14 @@
+package com.fsck.k9.mail.store.imap
+
+import com.fsck.k9.mail.ServerSettings
+import com.fsck.k9.mail.oauth.OAuth2TokenProvider
+import com.fsck.k9.mail.ssl.TrustedSocketFactory
+
+internal fun interface ImapStoreFactory {
+    fun create(
+        serverSettings: ServerSettings,
+        config: ImapStoreConfig,
+        trustedSocketFactory: TrustedSocketFactory,
+        oauthTokenProvider: OAuth2TokenProvider?,
+    ): ImapStore
+}

mail/protocols/imap/src/test/java/com/fsck/k9/mail/store/imap/FakeImapStore.kt

@@ -0,0 +1,28 @@
+package com.fsck.k9.mail.store.imap
+
+import kotlin.test.fail
+
+class FakeImapStore : ImapStore {
+    private var openConnectionCount = 0
+
+    var getFoldersAction: () -> List<FolderListItem> = { fail("getFoldersAction not set") }
+    val hasOpenConnections: Boolean
+        get() = openConnectionCount != 0
+
+    override fun checkSettings() {
+        throw UnsupportedOperationException("not implemented")
+    }
+
+    override fun getFolder(name: String): ImapFolder {
+        throw UnsupportedOperationException("not implemented")
+    }
+
+    override fun getFolders(): List<FolderListItem> {
+        openConnectionCount++
+        return getFoldersAction()
+    }
+
+    override fun closeAllConnections() {
+        openConnectionCount = 0
+    }
+}