Method and system for coordinating access to objects of different thread types in a shared memory space

• US 5,951,653 A
• Filed: 01/29/1997
• Issued: 09/14/1999
• Est. Priority Date: 01/29/1997
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hill, Richard D., Mitchell, Alexander A.
• Primary Examiner(s): Banankhah, Majid A.
• Application Number:
  US08/790,295
• Time in Patent Office: 958 Days
• Field of Search: 709/304, 709/303, 709/108, 709/100
• US Class Current: 719/315
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A computer-based method and system for accessing objects of different thread types in a single process. The system provides single-threaded apartments (STAs) for loading apartment-threaded objects and a multi-threaded apartment (MTA) for loading free-threaded objects. Each STA has a single thread, and the MTA has multiple threads. When an STA thread requests to access a free-threaded object, the system creates an MTA thread and requests the MTA thread to instantiate the free-threaded object. The STA thread then receives a marshalled pointer to the free-threaded object and unmarshals the received pointer. The STA thread then accesses the free-threaded object using the unmarshalled pointer so that the MTA thread accesses the free-threaded object on behalf of the STA thread. When an MTA thread requests access to an apartment-threaded object, the system creates an STA thread and requests the STA thread to instantiate the apartment-threaded object. The MTA thread then receives a marshalled pointer to the apartment threaded object and unmarshals the received pointer. The MTA thread then accesses the apartment-threaded object using the unmarshalled pointer so that the STA thread accesses the apartment-threaded object on behalf of the MTA thread.

Claims

1. A method in a computer system for accessing objects of different thread types in a single process, the method comprising:

during execution of a single-threaded apartment (STA) thread,

requesting access to a free-threaded object; and

in response to the request to access a free threaded object,

creating a multi-threaded apartment (MTA) thread;

requesting the MTA thread to instantiate the free threaded object;

receiving a marshalled pointer to the free-threaded object;

unmarshalling the received pointer; and

accessing the instantiated free-threaded object using the unmarshalled pointer wherein an MTA thread accesses the free-threaded object on behalf of the STA thread; and

during execution of an MTA thread,

requesting access to an apartment-threaded object; and

in response to the request to access an apartment-threaded object,

creating an STA thread;

requesting the STA thread to instantiate the apartment-threaded object;

receiving a marshalled pointer to the apartmnent-threaded object;

unmarshalling the received pointer; and

accessing the instantiated apartment-threaded object using the unmarshalled pointer wherein the STA thread accesses the apartment-threaded object on behalf of the MTA thread.

2. A method in a computer system for accessing a free-threaded object from a single-threaded apartment thread (STA) thread, the method comprising:

during execution of the STA thread,

requesting access to the free-threaded object; and

in response to the request to access a free-threaded object,

selecting a multi-threaded apartment (MTA) thread for accessing the object;

requesting the selected MTA thread to access the free-threaded object on behalf of the STA thread;

dispatching messages received while the MTA thread is accessing the free-threaded object; and

receiving notification that the MTA thread has completed accessing the free-threaded object.

3. The method of claim 2 wherein the selecting of an MTA thread includes creating an MTA thread.

4. The method of claim 2 wherein the selecting of an MTA thread selects an already created thread.

5. The method of claim 2 including before requesting access to the free-threaded object, receiving a marshalled pointer to the free-threaded object and unmarshalling the pointer and wherein the requesting of access to the free-threaded object uses the unmarshalled pointer.

6. The method of claim 2 including when the free-threaded object has not been instantiated, requesting the MTA thread to instantiate the free-threaded object wherein the MTA thread provides the STA thread with a marshalled pointer to the free-threaded object.

7. The method of claim 6 wherein the STA thread unmarshals the pointer and requests access to the free-threaded object using the unmarshalled pointer.

8. The method of claim 2 wherein the requesting of the selected MTA thread includes switching to the MTA thread.

9. A method in a computer system for accessing an apartment-threaded object from a multi-threaded apartment (MTA) thread, the method comprising:

during execution of the MTA thread,

requesting access to the apartment-threaded object; and

in response to the request to access the apartment-threaded object,

selecting a single-threaded apartment (STA) thread to access the object;

requesting the selected STA thread to access the apartment threaded object on behalf of the MTA thread;

suspending execution while the STA thread is accessing the apartment-threaded object; and

resuming execution when notified that the STA thread has completed accessing the apartment-threaded object.

10. The method of claim 9 wherein the selecting of an STA thread selects an already created thread.

11. The method of claim 9 wherein when the apartment-threaded object is a main-threaded object, then the selecting selects the main STA thread.

12. The method of claim 9 including before requesting access to the apartment-threaded object, receiving a marshalled pointer to the apartment-threaded object, and unmarshalling the pointer and wherein the requesting of access to the apartment-threaded object uses the unmarshalled pointer.

13. The method of claim 9 including when the apartment-threaded object has not been instantiated, requesting the STA thread to instantiate the apartment-threaded object wherein the STA thread provides the MTA thread with a marshalled pointer to the apartment-threaded object.

14. The method of claim 9 wherein the MTA thread unmarshals the pointer and requests access to the apartment-threaded object using the unmarshalled pointer.

15. A method in a computer system for providing access to apartment-threaded objects and free-threaded objects in memory shared by multiple threads, the method comprising:

creating a single-threaded apartment having a single-threaded apartment (STA) thread, each apartment object being loaded into the single-threaded apartment;

creating a multi-threaded apartment having multiple multi-threaded apartment (MTA) threads, each free-threaded object being loaded into the multi-threaded apartment;

when the STA thread requests to access a free-threaded object, accessing the free-threaded object from a selected MTA thread on behalf of the STA thread; and

when a MTA thread requests to accesses an apartment-threaded object, accessing the apartment threaded object from the STA thread on behalf of the MTA thread.

16. The method of claim 15 wherein the STA thread dispatches messages while the MTA thread is accessing the free-threaded object.

17. The method of claim 15 wherein the MTA thread suspends while the STA thread is accessing the apartment-threaded object.

18. The method of claim 15 wherein the STA thread provides a pointer to a marshalled host object and wherein the MTA thread unmarshals the pointer to the host object and invokes a method of the host object to instantiate an apartment-threaded object and to return a marshalled pointer to the instantiated object.

19. The method of claim 18 wherein the MTA thread unmarshals the pointer to the instantiated object and uses the unmarshalled pointer to request access to the instantiated object.

20. The method of claim 15 wherein an MTA thread provides a pointer to a marshalled host object and wherein the STA thread unmarshals the pointer to the host object and invokes a method of the host object to instantiate a free-threaded object and to return a marshalled pointer to the instantiated object.

21. The method of claim 20 wherein the STA thread unmarshals the pointer to the instantiated object and uses the unmarshalled pointer to request access to the instantiated object.

22. A computer-readable medium containing instructions for causing a computer system to provide access to apartment-threaded objects and free-threaded objects in memory shared by multiple threads, by:

creating a single-threaded apartment having a single-threaded apartment (STA) thread, each apartment object being loaded into the single threaded apartment;

creating a multi-threaded apartment having multiple multi-threaded apartment (MTA) threads, each free-threaded object being loaded into the multi-threaded apartment;

when the STA thread requests to access a free-threaded object, creating an MTA thread and accessing the free-threaded object from created MTA thread on behalf of the STA thread; and

when a MTA thread requests to accesses an apartment-threaded object, accessing the apartment threaded object from the STA thread on behalf of the MTA thread.

23. The computer-readable medium of claim 22 wherein the STA thread dispatches messages while the MTA thread is accessing the free-threaded object.

24. The computer-readable medium of claim 22 wherein the MTA thread suspends while the STA thread is accessing the apartment-threaded object.

25. The computer-readable medium of claim 22 wherein the STA thread provides a pointer to a marshalled host object and wherein the MTA thread unmarshals the pointer to the host object and invokes a method of the host object to instantiate an apartment-threaded object and to return a marshalled pointer to the instantiated object.

26. The computer-readable medium of claim 25 wherein the MTA thread unmarshals the pointer to the instantiated object and uses the unmarshalled pointer to request access to the instantiated object.

27. The computer-readable medium of claim 22 wherein an MTA thread provides a pointer to a marshalled host object and wherein the STA thread unmarshals the pointer to the host object and invokes a method of the host object to instantiate a free-threaded object and to return a marshalled pointer to the instantiated object.

28. The computer-readable medium of claim 27 wherein the STA thread unmarshals the pointer to the instantiated object and uses the unmarshalled pointer to request access to the instantiated object.