Log cursor/adapter class name and such when detecting a crash

Also log where the cursor was closed, if it is.

To investigate bug 3308465 and bug 3305706

Change-Id: I2b0fd9ea14757b6cf7597cd7162686d050d43fe9

src/com/android/email/Utility.java

@@ -37,6 +37,7 @@ import android.content.pm.ActivityInfo;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.database.Cursor;
+import android.database.CursorWrapper;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.AsyncTask;
@@ -1180,4 +1181,78 @@ public class Utility {
         }
         return name;
     }
+
+    /**
+     * Stringify a cursor for logging purpose.
+     */
+    public static String dumpCursor(Cursor c) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("[");
+        while (c != null) {
+            sb.append(c.getClass()); // Class name may not be available if toString() is overridden
+            sb.append("/");
+            sb.append(c.toString());
+            if (c.isClosed()) {
+                sb.append(" (closed)");
+            }
+            if (c instanceof CursorWrapper) {
+                c = ((CursorWrapper) c).getWrappedCursor();
+                sb.append(", ");
+            } else {
+                break;
+            }
+        }
+        sb.append("]");
+        return sb.toString();
+    }
+
+    /**
+     * Cursor wrapper that remembers where it was closed.
+     *
+     * Use {@link #get} to create a wrapped cursor.
+     * USe {@link #getTraceIfAvailable} to get the stack trace.
+     * Use {@link #log} to log if/where it was closed.
+     */
+    public static class CloseTraceCursorWrapper extends CursorWrapper {
+        private static final boolean TRACE_ENABLED = true; // STOPSHIP make it false
+
+        private Exception mTrace;
+
+        private CloseTraceCursorWrapper(Cursor cursor) {
+            super(cursor);
+        }
+
+        @Override
+        public void close() {
+            mTrace = new Exception("STACK TRACE");
+            super.close();
+        }
+
+        public static Exception getTraceIfAvailable(Cursor c) {
+            if (c instanceof CloseTraceCursorWrapper) {
+                return ((CloseTraceCursorWrapper) c).mTrace;
+            } else {
+                return null;
+            }
+        }
+
+        public static void log(Cursor c) {
+            if (c == null) {
+                return;
+            }
+            if (c.isClosed()) {
+                Log.w(Email.LOG_TAG, "Cursor was closed here: Cursor=" + c, getTraceIfAvailable(c));
+            } else {
+                Log.w(Email.LOG_TAG, "Cursor not closed.  Cursor=" + c);
+            }
+        }
+
+        public static Cursor get(Cursor original) {
+            return TRACE_ENABLED ? new CloseTraceCursorWrapper(original) : original;
+        }
+
+        /* package */ static CloseTraceCursorWrapper alwaysCreateForTest(Cursor original) {
+            return new CloseTraceCursorWrapper(original);
+        }
+    }
 }

src/com/android/email/activity/AccountSelectorAdapter.java

@@ -16,7 +16,9 @@
 
 package com.android.email.activity;
 
+import com.android.email.Email;
 import com.android.email.R;
+import com.android.email.Utility;
 import com.android.email.data.ThrottlingCursorLoader;
 import com.android.email.provider.EmailContent;
 import com.android.email.provider.EmailContent.Account;
@@ -203,7 +205,7 @@ public class AccountSelectorAdapter extends CursorAdapter {
                         countAccounts, countAccounts));
                 rb.add(totalUnread);
             }
-            return resultCursor;
+            return Utility.CloseTraceCursorWrapper.get(resultCursor);
         }
     }
 
@@ -225,4 +227,18 @@ public class AccountSelectorAdapter extends CursorAdapter {
             super.close();
         }
     }
+
+    // STOPSHIP delete this
+    @Override
+    public long getItemId(int position) {
+        try {
+            return super.getItemId(position);
+        } catch (RuntimeException re) {
+            final Cursor c = getCursor();
+            android.util.Log.w(Email.LOG_TAG, "Crash in getItemId, this=" + this
+                    + "  cursor=" + Utility.dumpCursor(c), re);
+            Utility.CloseTraceCursorWrapper.log(c);
+            throw re;
+        }
+    }
 }

src/com/android/email/activity/MailboxesAdapter.java

@@ -378,7 +378,7 @@ import android.widget.TextView;
         public Cursor loadInBackground() {
             final Cursor mailboxesCursor = super.loadInBackground();
             if (mMode == MODE_MOVE_TO_TARGET) {
-                return mailboxesCursor;
+                return Utility.CloseTraceCursorWrapper.get(mailboxesCursor);
             }
 
             // Add "Starred".
@@ -386,7 +386,7 @@ import android.widget.TextView;
             // starred.
             final int starredCount = Message.getFavoriteMessageCount(mContext);
             if (starredCount == 0) {
-                return mailboxesCursor; // no starred message
+                return Utility.CloseTraceCursorWrapper.get(mailboxesCursor); // no starred message
             }
 
             final MatrixCursor starredCursor = new MatrixCursor(getProjection());
@@ -394,7 +394,8 @@ import android.widget.TextView;
             addSummaryMailboxRow(mContext, starredCursor,
                     Mailbox.QUERY_ALL_FAVORITES, Mailbox.TYPE_MAIL, starredCount, true);
 
-            return new MergeCursor(new Cursor[] {starredCursor, mailboxesCursor});
+            return Utility.CloseTraceCursorWrapper.get(
+                    new MergeCursor(new Cursor[] {starredCursor, mailboxesCursor}));
         }
     }
 
@@ -440,7 +441,7 @@ import android.widget.TextView;
                 accounts.close();
             }
 
-            return combinedWithAccounts;
+            return Utility.CloseTraceCursorWrapper.get(combinedWithAccounts);
         }
     }
 
@@ -501,4 +502,18 @@ import android.widget.TextView;
     /* package */ static int getUnreadCountForTest(Cursor cursor) {
         return cursor.getInt(COLUMN_UNREAD_COUNT);
     }
+
+    // STOPSHIP delete this
+    @Override
+    public long getItemId(int position) {
+        try {
+            return super.getItemId(position);
+        } catch (RuntimeException re) {
+            final Cursor c = getCursor();
+            android.util.Log.w(Email.LOG_TAG, "Crash in getItemId, this=" + this
+                    + "  cursor=" + Utility.dumpCursor(c), re);
+            Utility.CloseTraceCursorWrapper.log(c);
+            throw re;
+        }
+    }
 }

src/com/android/email/activity/MessagesAdapter.java

@@ -227,7 +227,21 @@ import java.util.Set;
             setSelection(Utility.buildMailboxIdSelection(mContext, mMailboxId));
 
             // Then do a query.
-            return super.loadInBackground();
+            return Utility.CloseTraceCursorWrapper.get(super.loadInBackground());
+        }
+    }
+
+    // STOPSHIP delete this
+    @Override
+    public long getItemId(int position) {
+        try {
+            return super.getItemId(position);
+        } catch (RuntimeException re) {
+            final Cursor c = getCursor();
+            android.util.Log.w(Email.LOG_TAG, "Crash in getItemId, this=" + this
+                    + "  cursor=" + Utility.dumpCursor(c), re);
+            Utility.CloseTraceCursorWrapper.log(c);
+            throw re;
         }
     }
 }

tests/src/com/android/email/UtilityUnitTests.java

@@ -24,6 +24,9 @@ import com.android.email.provider.EmailContent.Mailbox;
 import com.android.email.provider.ProviderTestUtils;
 
 import android.content.Context;
+import android.database.Cursor;
+import android.database.CursorWrapper;
+import android.database.MatrixCursor;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
@@ -34,6 +37,7 @@ import android.telephony.TelephonyManager;
 import android.test.AndroidTestCase;
 import android.test.MoreAsserts;
 import android.test.suitebuilder.annotation.SmallTest;
+import android.text.TextUtils;
 import android.util.Log;
 import android.widget.ListView;
 import android.widget.TextView;
@@ -435,6 +439,46 @@ public class UtilityUnitTests extends AndroidTestCase {
         return ret;
     }
 
+    public void testDumpCursor() {
+        // Just make sure the method won't crash and returns non-empty string.
+        final Cursor c1 = new MatrixCursor(new String[] {"col"});
+        final Cursor c2 = new CursorWrapper(c1);
+
+        // Note it's a subclass of CursorWrapper.
+        final Cursor c3 = new CursorWrapper(c2) {
+        };
+
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c1)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c2)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c3)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(null)));
+
+        // Test again with closed cursor.
+        c1.close();
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c1)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c2)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(c3)));
+        assertFalse(TextUtils.isEmpty(Utility.dumpCursor(null)));
+    }
+
+    public void testCloseTraceCursorWrapper() {
+        final Cursor org = new MatrixCursor(new String[] {"col"});
+        final Utility.CloseTraceCursorWrapper c =
+                Utility.CloseTraceCursorWrapper.alwaysCreateForTest(org);
+
+        // Not closed -- no stack trace
+        assertNull(Utility.CloseTraceCursorWrapper.getTraceIfAvailable(c));
+        Utility.CloseTraceCursorWrapper.log(c); // shouldn't crash
+
+        // Close, now stack trace should be available
+        c.close();
+        assertNotNull(Utility.CloseTraceCursorWrapper.getTraceIfAvailable(c));
+        Utility.CloseTraceCursorWrapper.log(c);
+
+        // shouldn't crash
+        Utility.CloseTraceCursorWrapper.log(null);
+    }
+
     /**
      * A {@link ListView} used by {@link #testListStateSaver}.
      */