System for object oriented dynamic linking based upon a catalog of registered function set or class identifiers

• US 5,615,400 A
• Filed: 06/30/1993
• Issued: 03/25/1997
• Est. Priority Date: 06/30/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Quinn, Michael J., Plummer, Christopher J., Cowsar, George C.
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): Banankhah, Majid A.
• Application Number:
  US08/085,187
• Time in Patent Office: 1,364 Days
• Field of Search: 395/700, 395/157, 395/156, 395/164, 395/650, 364/DIG. 1
• US Class Current: 719/332
• CPC Class Codes: G06F 9/44521 Dynamic linking or loading; Link editing at or after load time, e.g. Java class loading
• CPC Class Codes: G06F 9/44536 Selecting among different versions
• CPC Class Codes: G06F 9/4488 Object-oriented

Abstract

A system is provided for managing code resources for use by client applications in a computer, wherein the computer has internal memory storing at least one client application. The apparatus comprises a resource set catalog stored in the internal memory. The resource set catalog identifies a plurality of function sets of functions by respective function set IDs. Further, the resource set catalog includes set records which characterize the functions within the respective sets. A dispatch engine, in the internal memory, linked with a client application, supplies a particular function set ID in response to a call by the client application of a particular function which is a member of a corresponding function set identified by the particular function set ID. A lookup engine in the internal memory, coupled with the resource set catalog and the dispatch engine, is responsive to the particular function set ID to look up a set record for a corresponding function set in the resource set catalog. Finally, a link engine in the internal memory and coupled with the dispatch engine returns the particular function to the client application in response to the set record. Thus, because the link engine is responsive to the set record, which is not linked with the client, the client need not be aware of changes in the structure of the library in which the particular function set resides. Thus, the function set can be moved into and out of internal memory, revised, placed in different sections of internal memory, and otherwise handled independently of the client, without requiring re-compilation of the client application.

Claims

1. A computer, comprising

a central processing unit;

non-volatile memory;

high-speed memory;

a library of function sets, each function set including at least one member function, embodied in the high-speed memory;

computer readable program code comprising one or more client applications embodied in the non-volatile memory and capable of utilizing and residing in the high-speed memory; and

computer readable program code means, embodied in the non-volatile memory, for managing use of functions by said one or more client applications, the computer readable program code means comprising;

computer readable program code means for causing the computer to store a dispatch record for said one or more client applications, each said dispatch record for said one or more client applications including a function set ID for each of said plurality of function sets used by said client application;

computer readable program dispatch code means responsive to a call by the client application of a particular member function and to the dispatch record for causing the computer to supply a request for a link to a function set having the particular member function; and

computer readable program link code means, responsive to the request for the link to the function set and to the function set ID in the dispatch record, for causing the computer to link the particular member function to the client application wherein the link code means includes

computer readable program code means for causing said computer to create a resource set catalog, the resource set catalog identifying function sets in the library by respective function set IDs, and storing a plurality of set records which characterize member functions within respective sets;

computer readable program lookup code means for causing the computer to look up a set record for the function set in the resource set catalog based on the corresponding function set ID; and

programmable code means, responsive to the set record, for causing the computer to return the particular member function to the client application.

2. The computer of claim 1, wherein the library of function sets includes at least one function set which characterizes a class.

3. The apparatus of claim 2, wherein the at least one function set which characterizes a class includes a constructor function and a destructor function.

4. The apparatus of claim 2, wherein the at least one function set which characterizes a class includes a virtual function.

5. The apparatus of claim 2, wherein the at least one function set which characterizes a class includes at least the following functions:

a constructor function, a destructor function, a virtual function and a non-virtual function.

6. The computer of claim 1, wherein the computer readable dispatch code means includes:

a first level dispatch code segment linked to the client application and to a global variable in the high speed memory; and

a second level dispatch code segment linked to the global variable and the link code means.

7. The computer of claim 1, wherein the code means directing the computer to create a dispatch record includes code means causing the computer to create a function link cache with said dispatch record to store the function link to the particular member function;

the link code means further includes code means for causing the computer to supply the function link to the function link cache in response to the return of the particular member function to the client application; and

the dispatch code means further includes code means for causing the computer to query the function link cache for a cached link to the particular member function, and to jump to the particular member function in response to the cached link.

8. The computer of claim 1, wherein the dispatch record includes code means directing a set link cache to store a set link to the function set including the particular member function;

the link code means includes code means for causing the computer to supply the set link to the set link cache in response to the return of the particular member function to the client application; and

the dispatch code means includes a code means for causing the computer to query the set link cache for a cached link to the function set, and return the cached link to the link code means upon a call to a member function in the function set of the particular member function.

9. The computer of claim 8, wherein the function sets are assigned version numbers according to a standard protocol, and the dispatch record further includes version information linked with one of the client applications indicating a minimum version number supported by said one of the client applications for the function set of the particular member function;

the library includes a version number for the corresponding function sets; and

the link code means further includes code means, responsive to the version information in the dispatch record and the version number in the library, for ensuring that the client application supports a version of the function set of the particular member function.

10. The computer of claim 8, further including computer readable code means for causing the computer to load the function sets into high speed memory, to assign the function sets in the library serial numbers when the function sets are loaded in high speed memory, and to assign a serial number in the dispatch record, indicating the serial number corresponding to each function set when the set link cache is filled with set links,

the set link cache stores a pointer to a link structure in high speed memory, and the link structure includes a pointer for linking to the function set, and

the link code means further includes code means, responsive to the serial number in the library of the function set and the serial number in the dispatch record, for ensuring validity of the set link cache entry, and code means for clearing the link structure when the corresponding function set is unloaded from internal memory.

11. The computer of claim 8, wherein the library of function sets further includes use count records for function sets in the library and the link code means further includes code means for causing the computer to increment the use count record when the function set is returned to the client application, and to decrement the use count when the client application frees the function set.

12. The computer of claim 2, wherein the at least one function set which characterizes a class includes a constructor function and a destructor function and the library further includes use count records for function sets in the library;

the link code means further includes code means for directing the computer to increment the use count record for a particular function set when a client application calls a constructor function for a class characterized by the function set, and to decrement the use count record when a client application calls a destructor function for the class; and

further including programmable code means, responsive to the use count records in the library, for causing the computer to free corresponding function sets from internal memory when the use count record goes to zero.

13. The computer of claim 1, including programmable code means embodied in the non-volatile memory for causing the computer to create a plurality of link structures in high-speed memory, and wherein a subset of the function sets are stored in non-volatile memory and may be loaded into high-speed memory by the link code means, the link code means causing the computer to assign serial numbers to the function sets when loaded in high-speed memory;

the dispatch record further includes a set link cache to store a pointer to one of the plurality of link structures and to store a serial number indicating a serial number of the corresponding function set when the set link cache is filled;

the link structure includes a pointer for linking to the function set;

the link code means further includes code means for causing the computer to supply the link to the function set, to return a particular member function to the client application, and to supply the serial number to the set link cache in response to the return of the particular member function to the client application; and

the dispatch code means further includes programmable code means for causing the computer to query the set link cache for a cached link, and if the serial number in the set link cache matches the serial number in the library, to return the cached link to the link code means upon a call to a member function in the function set of the particular member function.

14. The computer of claim 1, wherein the link code means includes:

means for causing the computer to create a catalog in the internal memory which lists function sets available for linking; and

programmable registration code means, in the high-speed memory, for causing the computer to insert function sets in the library in the catalog in response to a request by an operating system to make the library available for linking, and to remove the function sets in the library from the catalog in response to a request by the operating system to make the library unavailable for linking.

15. The computer of claim 1, wherein the link code means includes:

means for causing the computer to create a catalog in the internal memory which lists function sets available for linking; and

programmable registration code means, executable during runtime of the client application and in the high-speed memory, for causing the computer to insert function sets in the library in the catalog in response to a request by an operating system to make the library available for linking, and removes the function sets in the library from the catalog in response to a request by the operating system to make the library unavailable for linking.

16. A computer, comprising:

an input;

a central processing unit;

non-volatile memory;

internal memory;

at least one client application embodied in internal memory; and

programmable code means for managing code resources for use by client applications in the computer, the programmable code means, comprising;

a resource set catalog stored in the internal memory, the resource set catalog identifying a plurality of function sets of member functions by respective function set IDs, and storing a plurality of set records which characterize member functions within respective sets;

dispatch code means, in the internal memory linked with a client application, for causing the computer to supply a particular function set ID in response to a call by a client application of a particular member function which is a member of the a function set identified by the particular function set ID in the resource set catalog;

lookup code means, in the internal memory, for causing the computer to identify, based upon the resource set catalog and responsive to the dispatch code means, one of said plurality of set records for the corresponding function set in the resource set catalog; and

link code means, in the internal memory and responsive to the dispatch code means, for causing the computer to return the particular member function to the client application in response to the set record.

17. The computer of claim 16, wherein the dispatch code means comprises:

a dispatch record, linked with the client application, which stores the particular function set ID; and

dispatch linked to the dispatch record and the lookup engine, responsive to the call to supply the particular function set ID to the lookup engine.

18. The computer of claim 17, wherein the dispatch record includes a set link cache to store a link to the set record for the set of functions including the particular member function;

the link code means further includes code means for causing the computer to supply the link to the set link cache in response to the return of the particular member function to the client; and

the dispatch code means further includes code means for causing the computer to query the set link cache for a stored link to the set record, and to return the set record to the link engine in response to the cached link upon a call to a member function in the function set of the particular member function.

19. The computer of claim 18, wherein the set records for function sets are assigned serial numbers when the function sets are loaded in internal memory, and the dispatch record further includes a serial number, linked with the client, indicating a serial number of the corresponding function set when the set link cache is filled;

wherein the set link cache stores a pointer to a link structure in internal memory, and the link structure includes a pointer to the set record having the particular function set ID of the set record, and

wherein the link code means further includes code means, responsive to the serial number in the set record and the serial number in the dispatch record, for causing the computer to insure validity of the set link cache entry, and to clear the link structure when the corresponding function set is unloaded.

20. The computer of claim 17, wherein the set record further includes a use count record and the link code means further includes code means for causing the computer to increment the use count when a client application binds with the function set corresponding to the set record, and to decrement the use count when a client application frees the function set corresponding to the set record.

21. The computer of claim 18, wherein the at least one function set which characterizes a class includes a constructor function and a destructor function, and the set record further includes a use count field;

wherein the link code means further includes code means for causing the computer to increment the use count when a client application calls a constructor function for a class corresponding to the set record, and to decrement the use count when a client application calls a destructor function for a class corresponding to the set record; and

further including code means, responsive to the use counts in the set records, for causing the computer to free corresponding function sets from internal memory when the use count goes to zero.

22. The computer of claim 20, including a plurality of link structures in internal memory, and wherein the function sets are loaded into internal memory and are assigned serial numbers when loaded in internal memory;

the dispatch record includes a set link cache to store a pointer to one of the plurality of link structures and to store a serial number indicating a serial number of a corresponding function set when the set link cache is filled;

the link structure includes a pointer to the set record; and

the link code means further includes code means for causing to computer to supply the link and the serial number to the set link cache in response to the return of the particular function to the client;

the dispatch code means further includes code means for causing the computer to query the set link cache for a stored link to the set record, and, if the serial number in the set link cache matches the serial number in the set record, to return the set record to the link engine in response to the cached link upon a call to a member function in the function set of the particular member function.

23. The computer of claim 16, further including:

registration code means in the internal memory for causing the computer to insert a library of function sets in the resource set catalog in response to a request to make the library available for linking, and to remove the function sets in the library from the resource catalog in response to a request to make the library unavailable for linking.

24. The computer of claim 16, further including:

registration code means, executable during runtime of the client application and in the internal memory, for causing the computer to insert a library of function sets in the resource set catalog in response to a request to make the library available for linking, and to remove the function sets in the library from the resource set catalog in response to a request to make the library unavailable for linking.

25. An article of manufacture, comprising:

a computer usable medium having computer readable program code means embodied therein for managing code resources used by client applications in a computer, said program code means comprising;

code resources comprising a library of function sets stored on the computer usable medium, the function sets in the library having function set IDs, and the function sets including member functions;

program code means for causing the computer to create a resource set catalog, the resource set catalog identifying function sets in the library by respective function set IDs, and to store a plurality of set records which characterize member functions within respective sets;

dispatch code means, linked with a client application, for causing the computer to supply a particular function set ID in response to a call by the client application of a particular member function which is a member of a corresponding function set identified by the particular function set ID;

program lookup code means, responsive to the particular function set ID, for causing the computer to query the resource set catalog to look up a set record for the corresponding function set in the resource set catalog; and

program link code means, for causing the computer to return the particular member function from the library to the client application in response to the set record, and to write valid links in the function link cache and the set link cache,

wherein the dispatch code means includes;

a dispatch record linked with the client application which stores the particular function set ID,

a function link cache, linked with the client application, to store a link to the particular member function,

a set link cache, linked with the client application to store a link to the set record for the set of functions including the particular member function,

a dispatch code means linked to the dispatch record, the function link cache, the set link cache and the lookup engine, responsive to the call to supply the particular member function if the function link cache is valid, for causing the computer to supply the set record if the set link cache is valid and to supply the particular function set ID if neither the function link cache nor set link cache is valid.

26. The article of manufacture of claim 25, wherein the library comprises at least one function set which characterizes a class.

27. The article of manufacture of claim 26, wherein the at least one function set which characterizes a class includes a constructor function and a destructor function.

28. The article of manufacture of claim 26, wherein the at least one function set which characterizes a class includes a virtual function in the class.

29. The article of manufacture of claim 26, wherein the at least one function set which characterizes a class includes a constructor function, a destructor function, a virtual function and a non-virtual function.

30. The article of manufacture of claim 25, wherein the function sets in the library are assigned version numbers according to a standard protocol, and dispatch record further includes version information linked with the client indicating a minimum version number supported by the client for the function set of which the particular function is a member,

the set record includes a version number for the corresponding function set, and

the link code means includes means, responsive to the version information in the dispatch record and the version number in the set record, for causing the computer to insure that the client supports a version of the particular function in the function set.

31. The article of manufacture of claim 25, wherein the set records for function sets are assigned serial numbers when the function sets are loaded in internal memory, and the dispatch record further includes a serial number linked with the client indicating a serial number of the corresponding function set when the set link cache is filled,

the set link cache stores a pointer to a link structure in internal memory, and the link structure includes a pointer to the set record having the particular function set ID of the set record, and

the link code means further includes means, responsive to the serial number in the set record and the serial number in the dispatch record, for causing the computer to insure validity of the set link cache entry, and means for clearing the link structure when the corresponding function set is unloaded.

32. The article of manufacture of claim 25, wherein the set record includes a use count record and the link means includes means for causing the computer to increment the use count when a client application binds with the function set corresponding to the set record, and to decrement the use count when a client application frees the function set corresponding to the set record.

33. The article of manufacture of claim 26, wherein the at least one function set which characterizes a class includes a constructor function and a destructor function and the set record further includes a use count field;

the link means includes means for causing the computer to increment the use count when a client application calls a constructor function for a class corresponding to the set record, and to decrement the use count when a client application calls a destructor function for a class corresponding to the set record; and

further including means, responsive to the use counts in the set records, to free corresponding function sets from internal memory when the use count goes to zero.

34. The article of manufacture of claim 25, including a plurality of link structures in internal memory, and wherein the function sets are assigned serial numbers when loaded in internal memory;

the set link cache stores a pointer to one of the plurality of link structures and a serial number indicating a serial number of the corresponding function set when the set link cache is filled;

the link structure includes a pointer to the set record; and

the link means includes means causing the computer to supply the link and the serial number to the set link cache in response to the return of the particular member function to the client;

the dispatch means includes means to insure the validity of a cached link to the set record in response to the serial number in the set link cache and the serial number in the set record.

35. The article of manufacture of claim 25, further including:

a registration routine in the memory which inserts a library of function sets in the resource set catalog in response to a request to make the library available for linking, and removes the function sets in the library from the resource catalog in response to a request to make the library unavailable for linking.

36. The article of manufacture of claim 25, further including:

a registration routine executable during runtime of the client application and in the memory, which inserts a library of function sets in the resource set catalog in response to a request to make the library available for linking, and removes the function sets in the library from the resource set catalog in response to a request to make the library unavailable for linking.

37. In a computer, a computer readable memory having code means for managing functions for use by client applications in the computer, the computer having internal memory storing at least one client application and non-volatile memory, the code means comprising:

a resource catalog stored in the internal memory, the resource catalog including records identifying a plurality of functions available for dynamic linking with the client application;

dispatch code, in the internal memory linked with a client application, causing the computer to supply a request to link with a particular function in response to a call by the client application of the particular function;

lookup code in the internal memory, coupled with the resource catalog and the dispatch engine, causing the computer to look up a record for the particular function in the resource catalog in response to the request;

link code, in the internal memory and coupled with the dispatch engine, causing the computer to return the particular function to the client application in response to the record; and

registration code in the internal memory executable during runtime of the client application, which the inserts records for a library of functions in the resource catalog in response to a request to make the library available for linking, and removes the records for the library from the resource catalog in response to a request to make the library unavailable for linking.

38. A computer, including at least one central processing unit, non-volatile memory, high-speed memory, code means for managing code resources for use by client applications, the volatile memory storing at least one client application, the code means comprising:

a class catalog stored in the internal memory, the class catalog identifying a plurality of classes by respective class IDs, and storing class records which characterize derived classes, each derived class having at least one corresponding class in the plurality of classes from which the derived class is derived;

dispatch code in the internal memory linked with a client application, to supply a particular class ID in response to a call by the client application of a function of a particular class identified by the particular class ID;

lookup code in the internal memory, coupled with the class catalog and the dispatch engine, responsive to the particular class ID, causing the computer to look up a class record for the corresponding class in the class catalog;

link code in the internal memory and coupled with the dispatch engine, causing the computer to return the function of the particular class to the client application in response to the class record; and

library management code, coupled with the class catalog, causing the computer to provide information about a class in the class catalog to the client application in response to the class ID.

39. The computer of claim 38, wherein the class records identify classes from which the corresponding class is derived, and the library manager includes a verify class routine to verify that a particular class is derived from another class.

40. The computer of claim 38, wherein the class records identify parent classes of the corresponding class, and the library manager includes a cast object routine to return offsets within an object of a particular class to elements within the object of a parent class of the particular class.

41. The computer of claim 38, wherein the library manager includes a new object routine to provide parameters to the client application for calling a function of a class in response to the class ID.

42. The computer of claim 38, wherein the library manager includes a get class information routine to provide information to the client application about classes derived from a particular class in response to the class ID of the particular class.

43. A process for managing code resources used by a client application in a computer and dynamically installing client applications, the computer having internal memory storing at least one said client application, comprising:

providing a class identifier and link pointer in the client application;

providing a class catalog in the internal memory, the class catalog identifying a plurality of classes by respective class identifiers;

providing class records which contain information regarding each class and table records which characterize corresponding classes; and

updating the class catalog by generating a new object for inclusion in the class catalog, wherein said generating comprises means for;

querying the class identifier;

querying a memory pool;

determining, based on the class identified and memory allocation data, whether the memory pool allocation has been allocated to an object;

if the memory location has not been allocated, allocating the memory pool location to the new object;

determining the class record by querying one of the plurality of classes to determine whether the new object is supported by the class;

if the class is associated with a library other than a root library, then loading the library and incrementing a use counter in the table record;

retrieving the table record using the class record;

determining whether the new object is supported by the class based on the table record;

determining the size of the new object based on the object record;

placing the object in the allocated memory pool; and

incrementing the use counter.

44. A process executable in a computer, the computer including client applications in the computer, comprising the steps of:

providing a class identifier and link pointer in the client application;

providing a class catalog, the catalog stored in the internal memory, the class catalog identifying a plurality of classes by respective class identifiers, and storing class records which characterize corresponding classes, including at least one parent class having at least one class, each class comprising at least one object;

providing at least one operating system designated folder holding a register library;

determining whether new files are copied to or removed from the folder by the client application; and

updating the class catalog to include new library resources copied into the folder and deleting library resources which have been moved from the folder subsequent to use.

45. The process of claim 44 wherein the step of providing further includes the step of providing at least one client application designated folder.

46. The process of claim 45 wherein the step of determining further includes intercepting operating system calls indicating whether a file has been copied or moved, and means for determining whether the file is located in the operating system designated folder or the client application designated folder.

47. The process of claim 45 further including the step of determining whether the new file is a shared library resource prior to the step of updating the class catalog.

48. A computer readable memory for managing code resources for use by client applications in a computer, the computer having internal memory storing at least one client application, comprising:

a class catalog stored in the internal memory, the class catalog identifying a plurality of classes by respective class identifiers, and storing class records which characterize corresponding classes;

link code means, in the internal memory, for causing the computer to return the particular function to the client application in response to the class record;

library management code means, coupled with the class catalog, causing the computer to provide information about a class in the class catalog to the client application in response to a request to make the library unavailable for linking; and

a registration code means causing the computer to insert a library of function sets in the class catalog in response to a request to make the library available for linking, and to remove the function sets in the library from the class catalog in response to a request to make the library unavailable for linking.

49. The system of claim 48 further including:

cast object code means coupled to the client applications, allowing the client to cast an object of as a parent class, the cast object routine comprising;

code means for determining the location of the object and an identifier of the parent class;

code means for determining the class of the object based on a required structure for the object;

code means for verifying the class of the object using the class identification of the object and the parent class identifier;

code means for determining whether a single or multiple inheritance of the class is found; and

code means for determining offsets necessary for multiply inherent objects based on a hierarchy of parent classes.

50. The system of claim 48, wherein the catalogs are assigned version numbers according to a standard protocol, and including version information linked with the client application indicating a minimum version number supported by the client application for the function set of the particular member function,

the library includes a version number for the corresponding function sets, and

the link code further includes code, responsive to the version information in the dispatch record and the version number in the library, for causing the computer to insure that the client application supports a version of the function set of the particular member function.

51. A computer including internal memory storing at least one client application and non-volatile memory storing programmable code, the code comprising:

a class identifier and link pointer in the client application, upon compiling the client application;

a class catalog, the catalog stored in the internal memory, the class catalog identifying a plurality of classes by respective class identifiers, and storing class records which characterize corresponding classes, including at least one parent class including at least one class, each class comprising at least one object;

at least one operating system designated folder holding a register library;

means for determining whether new files are copied to or removed from the folder by the client application; and

update code means for including new library resources copied into the folder in the class catalog and deleting library resources which have been moved from the folder subsequent to use from the class catalog.

52. A computer including a central processing unit, volatile internal memory and non-volatile memory means for managing code resources for use by client applications in the computer, the computer having internal memory storing at least one client application, said means for managing code comprising:

means for providing a class identifier and link pointer in the client application;

means for providing a class catalog stored in the internal memory, the class catalog identifying a plurality of classes by respective class identifiers, and storing class records which characterize corresponding classes, including at least one parent class having at least one class, each class comprising at least one object;

means for providing at least one operating system designated folder and at least one client application designated folder, each holding at least one register library;

means for determining whether new files are copied to or removed from the folder by the client application;

means for determining whether the new file is a shared library resource; and

means for updating the class catalog to include new library resources copied into the folder and deleting library resources which have been moved from the folder subsequent to use.