Call back structures for user defined DOMs
Described herein are techniques that allow applications developed in non-object oriented languages, such as C, to interact with DOM trees implemented under different DOM implementations. An application accesses different DOM implementations through a set of function pointers that conform to a set of function signatures. The set of function pointers may be stored in a data structure defined to have member function pointers that point to functions that conform to the set of function signatures. The set of function signatures define a common interface through which applications may interact with a variety of DOM implementations. One or more applications generate the set of function pointers and store them in a data structure. The other applications register the function pointers with an application by, for example, passing a pointer to the data structure to the application.
1. A computer-implemented method for accessing data represented in multiple implementations of a Document Object Model (DOM), the method comprising the steps of:
a particular application setting a first set of function pointers to point to a first set of functions that conform to a particular set of signatures, wherein the first set of functions is associated with a first DOM implementation;
said particular application invoking the first set of functions to access first data represented in the first DOM implementation; and
said particular application setting a second set of function pointers to point to a second set of functions that conform to the particular set of signatures, wherein the second set of functions is associated with a second DOM implementation.
2. The method of claim 1 ,
wherein the first set of function pointers are members of a first data structure; and
wherein the steps further include modifying the members of the first data structure to point to a third set of functions after performing the step of invoking the first set of functions.
3. The method of claim 2 , wherein the second set of function pointers are members of an other data structure, and wherein said first data structure and said other data structure have the same data type.
4. The method of claim 3 , further including the step of said particular application generating said first data structure.
5. The method of claim 1 , wherein
the step of a particular application invoking the first set of functions includes invoking the first set of functions pointed to by members of a first data structure.
6. The method of claim 1 , wherein the step of invoking the first set of functions includes invoking functions implemented in an other application different than said particular application.
7. The method of claim 6 , further including the step of said particular application registering said first set of functions with said other application.
8. The method of claim 7 , wherein
the first set of function pointers are members of a data structure pointed to by a first pointer; and
the step of registering includes supplying said pointer to said particular application.
9. The method of claim 1 , wherein
the first set of function pointers are members of a first data structure pointed to by a first pointer;
a second data structure includes said first pointer as a member; and
said second data structure includes another member that refers to a DOM tree implemented according to said first DOM implementation.
10. A computer-readable storage medium carrying one or more sequences of instructions for accessing data represented in multiple implementations of a Document Object Model (DOM), wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:
a particular application setting a first set of function pointers to point to a first set of functions that conform to a particular set of signatures, wherein the first set of functions is associated with a first DOM implementation;
said particular application invoking the first set of functions to access first data represented in the first DOM implementation; and
said particular application setting a second set of function pointers to point to a second set of functions that conform to the particular set of signatures, wherein the second set of functions is associated with a second DOM implementation.
11. The computer-readable storage medium of claim 10 ,
wherein the first set of function pointers are members of a first data structure; and
wherein the steps further include modifying the members of the first data structure to point to a third set of functions after performing the step of invoking the first set of functions.
12. The computer-readable storage medium of claim 11 , wherein the second set of function pointers are members of an other data structure, and wherein said first data structure and said other data structure have the same data type.
13. The computer-readable storage medium of claim 12 , wherein the steps further include said particular application generating said first data structure.
14. The computer-readable storage medium of claim 10 , wherein
the step of a particular application invoking the first set of functions includes invoking the first set of functions pointed to by members of a first data structure.
15. The computer-readable storage medium of claim 10 , wherein the step of invoking the first set of functions includes invoking functions implemented in an other application different than said particular application.
16. The computer-readable storage medium of claim 15 , wherein the steps further include the step of said particular application registering said first set of functions with said other application.
17. The computer-readable storage medium of claim 16 , wherein
the first set of function pointers are members of a data structure pointed to by a first pointer; and
the step of registering includes supplying said pointer to said particular application.
18. The computer-readable storage medium of claim 10 , wherein
the first set of function pointers are members of a first data structure pointed to by a first pointer;
a second data structure includes said first pointer as a member; and
said second data structure includes another member that refers to a DOM tree implemented according to said first DOM implementation.