Body pane filesystem : fix timing and transition to get rid of vscode errors in debug console when de-hoisting/changing documents. about leointeg

[boltex]

Redo body pane file provider to be able to give out stats from any gnx in the leo document., as timing from vscode can be tricky if user expands notes or polls leo from some info to show parts of the tree that were refreshed from an earlier refresh call.

Might have to answer from other opened documents than the currently selected one, for example, if just switched from one document to the other.

[boltex]

Note: The node' id could be a double murmurhash of the "ap" json string, https://github.com/garycourt/murmurhash-js, doubled means 64 bit instead of 32. this would maintain node identity and replace the decorated incremented number used as of now... see https://security.stackexchange.com/questions/209882/can-a-32-bit-hash-be-made-into-a-64-bit-hash-by-calling-it-twice-with-different/210049#210049

function hash64(str) {
var h1 = hash32(str); // returns 32 bit (as 8 byte hex string)
return h1 + hash32(h1 + str); // 64 bit (as 16 byte hex string)
}

[boltex]

By using a double murmurhash of the "ap" json string, as id for outline nodes, and only refreshing them (by changing salt used with hash) when operations do actually change the tree (opposite of just navigating the tree) This will prevent refreshes and flashing/redraw.

[edreamleo]

@boltex Never heard of a murmurhash until just now. Google enlightened me. The general idea seems good.

[boltex]

Actually salt might be needed (see below)

Actually no need for 'Salt' at all: if the collaped state is part of the json data, the 64 (or whatever lenght) key will be different, thus refreshing the collapsed state if it changed.

[boltex]

Important: When browsing tree without changing it (navigating) having hashes for IDs will allow to use only 'reveal' method without any 'refreshes' needed at all! This will greatly benefit navigation experience!

[boltex]

Implementation Revision:
Salt is incremented with tree-changing operations , but stays the same when only navigating the tree. (up down, left right,..pgup/pgdn)

Salt is also needed, depending of navigation mode, when simply navigating the tree:

1- "Standard vscode" tree navigation mode

• change salt when collapsing / expanding, to change collapsed-state and set selection
  (consider expand/collapse to be tree changing)

2- "Leo" tree navigation mode

• dont change salt, just use reveal with the newly selected node as parameter.

[edreamleo]

@boltex Imo, this issue does not affect leoserver.py. I have removed the comment in leoserver.py.