Fix ClassCastException in QuickstepModelDelegate

- Added a casting check as an immediate fix to b/173838775
- Added logging to help debug the corrupt state where an item of type other than FolderInfo is used as an other item's container.
- Added LoaderMemoryLogger for adding large logs that are only conditionally printed.

Bug: 173838775
Test: manually checked logs
Change-Id: I9491cb421b9fb807d5fb110b04ad069481de768f

src/com/android/launcher3/model/LoaderMemoryLogger.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3.model;
+
+import android.util.Log;
+
+import androidx.annotation.Nullable;
+
+import java.util.ArrayList;
+
+/**
+ * Helper logger that collects logs while {@code LoaderTask#run} executes and prints them all iff
+ * an exception is caught in {@code LoaderTask#run}.
+ */
+public class LoaderMemoryLogger {
+
+    private static final String TAG = "LoaderMemoryLogger";
+
+    private final ArrayList<LogEntry> mLogEntries = new ArrayList<>();
+
+    protected LoaderMemoryLogger() {}
+
+    protected void addLog(int logLevel, String tag, String log) {
+        addLog(logLevel, tag, log, null);
+    }
+
+    protected void addLog(
+            int logLevel, String tag, String log, Exception stackTrace) {
+        switch (logLevel) {
+            case Log.ASSERT:
+            case Log.ERROR:
+            case Log.DEBUG:
+            case Log.INFO:
+            case Log.VERBOSE:
+            case Log.WARN:
+                mLogEntries.add(new LogEntry(logLevel, tag, log, stackTrace));
+                break;
+            default:
+                throw new IllegalArgumentException("Invalid log level provided: " + logLevel);
+
+        }
+    }
+
+    protected void clearLogs() {
+        mLogEntries.clear();
+    }
+
+    protected void printLogs() {
+        for (LogEntry logEntry : mLogEntries) {
+            String tag = String.format("%s: %s", TAG, logEntry.mLogTag);
+            String logString = logEntry.mStackStrace == null
+                    ? logEntry.mLogString
+                    : String.format(
+                            "%s\n%s",
+                            logEntry.mLogString,
+                            Log.getStackTraceString(logEntry.mStackStrace));
+
+            Log.println(logEntry.mLogLevel, tag, logString);
+        }
+        clearLogs();
+    }
+
+    private static class LogEntry {
+
+        protected final int mLogLevel;
+        protected final String mLogTag;
+        protected final String mLogString;
+        @Nullable protected final Exception mStackStrace;
+
+        protected LogEntry(
+                int logLevel, String logTag, String logString, @Nullable Exception stackStrace) {
+            mLogLevel = logLevel;
+            mLogTag = logTag;
+            mLogString = logString;
+            mStackStrace = stackStrace;
+        }
+    }
+}