Navigation of the content space of a document set
Content-based addressing is used to navigate forward, backward and in a circular fashion through documents in a content space. To enable backward navigation, a descriptor file is created for a new version that contains not only a message digest for the new version, but also a message digest of the older document. A message digest is created for the descriptor file. A user navigates backward starting with the message digest of the descriptor file. To enable forward navigation, a mapping table maps a message digest of an older document into the message digest of the new version. A high-level descriptor file contains the message digest of the original document and the message digest of the mapping table. The message digest of the high-level descriptor file is returned to the user. A user navigates forward starting with the high-level descriptor file message digest. To enable circular navigation, a mapping table maps a message digest of a second document into a message digest of a version of the second document containing a message digest of a first document. The techniques are combined to allow navigation through a complex content space.
1. A method of enabling forward navigation in a content space, said method comprising:
receiving a first message digest that identifies a first computer file;
receiving a second message digest that identifies a second computer file;
receiving an indication that said second computer file is a later version or said first computer file;
creating a mapping table that maps said first message digest into said second message digest;
creating a descriptor file that includes said first message digest and an identification of said mapping table; and
creating a third message digest of said descriptor file and returning said third message digest to a user, whereby said user uses said third message digest to navigate forward through said content space formed by said first and second computer files.
2. A method as recited in claim 1 wherein said first message digest is the digest of a first descriptor file that identifies said first computer file, wherein said second message digest is the digest of a second descriptor file that identifies said second computer file.
3. A method as recited in claim 2 wherein said first and second descriptor files include meta data concerning said first and second computer files, respectively.
4. A method as recited in claim 1 wherein said second computer file is received by said user or is created by said user.
5. A method as recited in claim 1 wherein said descriptor file includes meta data.
6. A method as recited in claim 1 wherein said descriptor file includes said mapping table.
7. A method as recited in claim 1 wherein said descriptor file includes a message digest that identifies said mapping table.