system: handle fallible databases

Handle errors from databases.

Either way, a crash from a database or a silent error will be equally
nightmarish to debug. May as well keep going if they fail.

app/src/main/java/org/oxycblt/auxio/music/extractor/CacheExtractor.kt

@@ -26,6 +26,7 @@ import androidx.core.database.getStringOrNull
 import androidx.core.database.sqlite.transaction
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.util.logD
+import org.oxycblt.auxio.util.logE
 import org.oxycblt.auxio.util.queryAll
 import org.oxycblt.auxio.util.requireBackgroundThread
 import java.io.File
@@ -42,7 +43,12 @@ class CacheExtractor(private val context: Context) {
     private var shouldWriteCache = false
 
     fun init() {
+        try {
             cacheMap = CacheDatabase.getInstance(context).read()
+        } catch (e: Exception) {
+            logE("Unable to load cache database.")
+            logE(e.stackTraceToString())
+        }
     }
 
     /**
@@ -55,16 +61,21 @@ class CacheExtractor(private val context: Context) {
             // If the entire library could not be loaded from the cache, we need to re-write it
             // with the new library.
             logD("Cache was invalidated during loading, rewriting")
+            try {
                 CacheDatabase.getInstance(context).write(rawSongs)
+            } catch (e: Exception) {
+                logE("Unable to save cache database.")
+                logE(e.stackTraceToString())
+            }
         }
     }
 
     /**
      * Maybe copy a cached raw song into this instance, assuming that it has not changed
-     * since it was last saved.
+     * since it was last saved. Returns true if a song was loaded.
      */
     fun populateFromCache(rawSong: Song.Raw): Boolean {
-        val map = requireNotNull(cacheMap) { "CacheExtractor was not properly initialized" }
+        val map = cacheMap ?: return false
 
         val cachedRawSong = map[rawSong.mediaStoreId]
         if (cachedRawSong != null && cachedRawSong.dateAdded == rawSong.dateAdded && cachedRawSong.dateModified == rawSong.dateModified) {

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -248,26 +248,32 @@ class PlaybackViewModel(application: Application) :
 
     // --- SAVE/RESTORE FUNCTIONS ---
 
-    /** Force save the current [PlaybackStateManager] state to the database. */
-    fun savePlaybackState(onDone: () -> Unit) {
+    /**
+     * Force save the current [PlaybackStateManager] state to the database. [onDone]
+     * will be called with true if it was done, or false if an error occurred.
+     */
+    fun savePlaybackState(onDone: (Boolean) -> Unit) {
         viewModelScope.launch {
-            playbackManager.saveState(PlaybackStateDatabase.getInstance(application))
-            onDone()
+            val saved = playbackManager.saveState(PlaybackStateDatabase.getInstance(application))
+            onDone(saved)
         }
     }
 
-    /** Wipe the saved playback state (if any). */
-    fun wipePlaybackState(onDone: () -> Unit) {
+    /**
+     * Wipe the saved playback state (if any). [onDone] will be called with true if it was
+     * successfully done, or false if an error occurred.
+     */
+    fun wipePlaybackState(onDone: (Boolean) -> Unit) {
         viewModelScope.launch {
-            playbackManager.wipeState(PlaybackStateDatabase.getInstance(application))
-            onDone()
+            val wiped = playbackManager.wipeState(PlaybackStateDatabase.getInstance(application))
+            onDone(wiped)
         }
     }
 
     /**
      * Force restore the last [PlaybackStateManager] saved state, regardless of if a library exists
      * or not. [onDone] will be called with true if it was successfully done, or false if there was
-     * no state or if a library was not present.
+     * no state, a library was not present, or there was an error.
      */
     fun tryRestorePlaybackState(onDone: (Boolean) -> Unit) {
         viewModelScope.launch {

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -29,6 +29,7 @@ import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.state.PlaybackStateManager.Callback
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.logD
+import org.oxycblt.auxio.util.logE
 import org.oxycblt.auxio.util.logW
 import kotlin.math.max
 
@@ -368,7 +369,13 @@ class PlaybackStateManager private constructor() {
 
         val library = musicStore.library ?: return false
         val internalPlayer = internalPlayer ?: return false
-        val state = withContext(Dispatchers.IO) { database.read(library) }
+        val state = try {
+            withContext(Dispatchers.IO) { database.read(library) }
+        } catch (e: Exception) {
+            logE("Unable to restore playback state.")
+            logE(e.stackTraceToString())
+            return false
+        }
 
         synchronized(this) {
             if (state != null && (!isInitialized || force)) {
@@ -397,15 +404,32 @@ class PlaybackStateManager private constructor() {
     }
 
     /** Save the current state to the [database]. */
-    suspend fun saveState(database: PlaybackStateDatabase) {
+    suspend fun saveState(database: PlaybackStateDatabase): Boolean {
         logD("Saving state to DB")
+
         val state = synchronized(this) { makeStateImpl() }
+        return try {
             withContext(Dispatchers.IO) { database.write(state) }
+            true
+        } catch (e: Exception) {
+            logE("Unable to save playback state.")
+            logE(e.stackTraceToString())
+            false
+        }
     }
 
-    suspend fun wipeState(database: PlaybackStateDatabase) {
+    /** Wipe the current state. */
+    suspend fun wipeState(database: PlaybackStateDatabase): Boolean {
         logD("Wiping state")
+
+        return try {
             withContext(Dispatchers.IO) { database.write(null) }
+            true
+        } catch (e: Exception) {
+            logE("Unable to wipe playback state.")
+            logE(e.stackTraceToString())
+            false
+        }
     }
 
     /** Sanitize the state with [newLibrary]. */

app/src/main/java/org/oxycblt/auxio/settings/prefs/PreferenceFragment.kt

@@ -113,13 +113,21 @@ class PreferenceFragment : PreferenceFragmentCompat() {
 
         when (preference.key) {
             context.getString(R.string.set_key_save_state) -> {
-                playbackModel.savePlaybackState {
+                playbackModel.savePlaybackState { saved ->
+                    if (saved) {
                         this.context?.showToast(R.string.lbl_state_saved)
+                    } else {
+                        this.context?.showToast(R.string.err_did_not_save)
+                    }
                 }
             }
             context.getString(R.string.set_key_wipe_state) -> {
-                playbackModel.wipePlaybackState {
+                playbackModel.wipePlaybackState { wiped ->
+                    if (wiped) {
                         this.context?.showToast(R.string.lbl_state_wiped)
+                    } else {
+                        this.context?.showToast(R.string.err_did_not_wipe)
+                    }
                 }
             }
             context.getString(R.string.set_key_restore_state) ->

app/src/main/res/values/strings.xml

@@ -251,7 +251,11 @@
     <string name="err_no_dirs">No folders</string>
     <string name="err_bad_dir">This folder is not supported</string>
     <!-- Referring to playback state -->
-    <string name="err_did_not_restore">No state could be restored</string>
+    <string name="err_did_not_restore">Unable to restore state</string>
+    <!-- Referring to playback state -->
+    <string name="err_did_not_wipe">Unable to clear state</string>
+    <!-- Referring to playback state -->
+    <string name="err_did_not_save">Unable to save state</string>
 
     <!-- Description Namespace | Accessibility Strings -->