Allow connections to be shared between threads (given check_same_thre…

…ad=False)

.gitignore

@@ -1,2 +1,5 @@
 .*.sw[a-z]
 *.py[co]
+build/
+dist/
+s3m.egg-info/

s3m.py

@@ -7,7 +7,7 @@
 
 __all__ = ["connect", "Connection", "S3MError", "LockTimeoutError"]
 
-version = "1.0.0"
+version = "1.0.1"
 
 # Global lock storage
 CONNECTION_LOCKS = {}
@@ -83,8 +83,11 @@ def __init__(self, path, lock_transactions=True, lock_timeout=-1, *args, **kwarg
         # Should parallel transactions be allowed?
         self.lock_transactions = lock_transactions
 
+        # This lock is used to control sharing of the connection between threads
+        self.personal_lock = threading.RLock()
+
         if self.path == ":memory:":
-            # No 2 :memory: connections point to the same database => locks are not needed
+            # No two :memory: connections point to the same database => locks are not needed
             self.lock = FakeLock()
             return
 
@@ -130,19 +133,24 @@ def __enter__(self):
             if not self.lock.acquire(timeout=self.lock_timeout):
                 raise LockTimeoutError(self)
 
+        if not self.personal_lock.acquire(timeout=self.lock_timeout):
+            raise LockTimeoutError(self)
+
         self.was_in_transaction = self.connection.in_transaction
 
     def __exit__(self, *args, **kwargs):
-        try:
-            # if the connection is closed, an exception is thrown
-            in_transaction = self.in_transaction
-        except sqlite3.ProgrammingError:
-            in_transaction = False
+        self.personal_lock.release()
 
         if not self.lock_transactions:
             self.lock.release()
             return
 
+        try:
+            # If the connection is closed, an exception is thrown
+            in_transaction = self.in_transaction
+        except sqlite3.ProgrammingError:
+            in_transaction = False
+
         # The lock should be released only if:
         # 1) the connection was previously in a transaction and now it isn't
         # 2) the connection wasn't previously in a transaction and still isn't

setup.py

@@ -4,7 +4,7 @@
 from setuptools import setup
 
 setup(name="s3m",
-      version="1.0.0",
+      version="1.0.1",
       description="sqlite3 wrapper for multi-threaded applications",
       author="Ivan Konovalov",
       py_modules=["s3m"])

tests/s3m_test.py

@@ -59,8 +59,9 @@ def test_s3m(self):
         self.assertEqual(result, [(1,), (2,), (3,)] * self.n_connections)
 
     def test_s3m_lock_transactions(self):
-        conn1 = self.connect_db(self.db_path, lock_transactions=False)
-        conn2 = self.connect_db(self.db_path, lock_transactions=False, check_same_thread=False)
+        conn1 = self.connect_db(self.db_path, lock_transactions=False, lock_timeout=0.5)
+        conn2 = self.connect_db(self.db_path, lock_transactions=False, lock_timeout=0.5,
+                                check_same_thread=False)
 
         def thread_func():
             conn2.execute("BEGIN TRANSACTION")
@@ -107,6 +108,28 @@ def test_in_memory2(self):
         conn1.commit()
         conn2.commit()
 
+    def test_sharing(self):
+        conn = self.connect_db(":memory:", check_same_thread=False)
+
+        conn.execute("CREATE TABLE a(id INTEGER)")
+        conn.execute("BEGIN TRANSACTION")
+
+        def func():
+            for i in range(25):
+                conn.execute("INSERT INTO a VALUES(?)", (i,))
+
+        thread = threading.Thread(target=func)
+
+        thread.start()
+        func()
+        thread.join()
+
+        conn.commit()
+
+        conn.execute("SELECT id FROM a")
+
+        self.assertEqual(len(conn.fetchall()), 50)
+
     def tearDown(self):
         try:
             os.remove(self.db_path)