nodemap: add a flag to dump the details of the docket We are about to add more information to the docket. We first introduce a way to debug its content. Differential Revision: https://phab.mercurial-scm.org/D7887

nodemap: introduce append-only incremental update of the persistent data Rewriting the full nodemap for each transaction has a cost we would like to avoid. We introduce a new way to write persistent nodemap data by adding new information at the end for file. Any new and updated block as added at the end of the file. The last block is the new root node. With this method, some of the block already on disk get "dereferenced" and become dead data. In later changesets, We'll start tracking the amount of dead data to eventually re-generate a full nodemap. Differential Revision: https://phab.mercurial-scm.org/D7886

nodemap: keep track of the docket for loaded data To perform incremental update of the on disk data, we need to keep tracks of some aspect of that data. Differential Revision: https://phab.mercurial-scm.org/D7885

nodemap: introduce an explicit class/object for the docket We are about to add more information to this docket, having a clear location to stock them in memory will help. Differential Revision: https://phab.mercurial-scm.org/D7884

nodemap: keep track of the ondisk id of nodemap blocks If we are to incrementally update the files, we need to keep some details about the data we read. Differential Revision: https://phab.mercurial-scm.org/D7883

nodemap: provide the on disk data to indexes who support it Time to start defining the API and prepare the rust index support. We provide a method to do so. We use a distinct method instead of passing them in the constructor because we will need this method anyway later (to refresh the mmap once we update the data on disk). Differential Revision: https://phab.mercurial-scm.org/D7847

nodemap: all check that revision and nodes match in the nodemap More check is always useful. Differential Revision: https://phab.mercurial-scm.org/D7846

nodemap: add basic checking of the on disk nodemap content The simplest check it so verify we have all the revision we needs, and nothing more. Differential Revision: https://phab.mercurial-scm.org/D7845

nodemap: code to parse the persistent binary nodemap data We now have code to read back what we persisted. This will be put to use in later changesets. Differential Revision: https://phab.mercurial-scm.org/D7844

nodemap: move the iteratio inside the Block object Having the iteration inside the serialization function does not help readability. Now that we have a `Block` object, let us move that code there. Differential Revision: https://phab.mercurial-scm.org/D7843

nodemap: use an explicit "Block" object in the reference implementation This will help us to introduce some test around the data currently written on disk. Differential Revision: https://phab.mercurial-scm.org/D7842

nodemap: add a optional `nodemap_add_full` method on indexes This method can be used to obtains persistent data for a full nodemap. The end goal is for some index implementation to managed the nodemap serialization them selves (eg: the rust implementation) Differential Revision: https://phab.mercurial-scm.org/D7841