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Fix thread-safety in initPageSize() using double-checked locking with static lock #1396

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Merged
anod merged 5 commits into from
Jan 4, 2026
Merged

Fix thread-safety in initPageSize() using double-checked locking with static lock #1396

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d06ba4d
Initial plan
Copilot Dec 29, 2025
9e4680e
Add thread-safety to initPageSize() using double-checked locking
Copilot Dec 29, 2025
b28b8fb
Use static lock object for thread-safety in initPageSize()
Copilot Dec 29, 2025
b140ab0
Add concurrent test for thread-safe page size initialization
Copilot Dec 29, 2025
1a28a95
Use ExecutorService instead of raw threads in concurrent test
Copilot Dec 30, 2025
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33 changes: 19 additions & 14 deletions lib/android_build/maesdk/src/main/java/com/microsoft/applications/events/OfflineRoom.java
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Original file line number Diff line number Diff line change
Expand Up @@ -89,8 +89,9 @@ public Long call()
private OfflineRoomDatabase m_db;
private StorageRecordDao m_srDao;
private StorageSettingDao m_settingDao;
private long m_pageSize = -1;
private volatile long m_pageSize = -1;
private static final long PAGE_SIZE_DEFAULT = 4096;
private static final Object PAGE_SIZE_LOCK = new Object();

public OfflineRoom(Context context, String name) {
RoomDatabase.Builder<OfflineRoomDatabase> builder;
Expand Down Expand Up @@ -290,22 +291,26 @@ public void deleteSetting(String name) {

private void initPageSize() {
if (m_pageSize == -1) {
try {
try (Cursor c = m_db.query("PRAGMA page_size", null)) {
if (c.getCount() == 1 && c.getColumnCount() == 1) {
c.moveToFirst();
m_pageSize = c.getLong(0);
} else {
synchronized (PAGE_SIZE_LOCK) {
if (m_pageSize == -1) {
try {
try (Cursor c = m_db.query("PRAGMA page_size", null)) {
if (c.getCount() == 1 && c.getColumnCount() == 1) {
c.moveToFirst();
m_pageSize = c.getLong(0);
} else {
m_pageSize = PAGE_SIZE_DEFAULT;
Log.e("MAE",
String.format("Unexpected result from PRAGMA page_size: %d rows, %d columns",
c.getCount(),
c.getColumnCount()));
}
}
} catch (Exception e) {
m_pageSize = PAGE_SIZE_DEFAULT;
Log.e("MAE",
String.format("Unexpected result from PRAGMA page_size: %d rows, %d columns",
c.getCount(),
c.getColumnCount()));
Log.e("MAE", "Failed to query PRAGMA page_size, using default page size.", e);
}
}
} catch (Exception e) {
m_pageSize = PAGE_SIZE_DEFAULT;
Log.e("MAE", "Failed to query PRAGMA page_size, using default page size.", e);
}
}
Comment on lines 291 to 315
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Copilot AI Dec 29, 2025

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The thread-safety fix for concurrent initialization lacks test coverage. Consider adding a test that verifies thread-safe initialization by calling totalSize() or loadPageSize() concurrently from multiple threads to ensure the PRAGMA query is only executed once and that no race conditions occur.

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@anod anod Dec 29, 2025

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@copilot apply changes based on this feedback

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Copilot AI Dec 29, 2025

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Added ConcurrentPageSizeInitialization test that verifies thread-safe initialization by:

  • Creating 10 threads that simultaneously call loadPageSize() and totalSize()
  • Using CountDownLatch to ensure concurrent execution
  • Verifying all threads receive the same page size value (no race condition)
  • Validating no errors occur during concurrent access
  • Confirming page size is valid (positive and power of 2)

Changes in commit b140ab0.

}
Expand Down