stash::items capped the items at MAX_ITEMS before reading them, so one
over the size limit took a place (a readable item past the cap was then
left out with fewer than MAX_ITEMS listed) and one past the cap was
counted in `more` though it could never be listed. Items are now read
first: the first MAX_ITEMS readable ones are listed and only readable
ones past them are counted.
stash::items and stash::keys listed the first 10,000 items and let the rest
vanish without a word. They return a Listing { found, more } now, so a caller
can say what it did not list.
The guard asked for a hidden name, but the stash reads a legacy _sc_<key>
name whether it is hidden or not, so a visible one could be removed or
replaced without force. stash::holds_item is the one rule (item_of), shared
by the guard; the test covers a visible legacy name.
Each `stash::get` looks at every defined name, so listing the items
with `keys` and then reading each with `get` took time quadratic in
the number of names. A file with 20,000 hidden `_gc_macro_<i>_0`
names took about ten seconds in a debug build, and the macro list
reads its items this way from data that comes from the file.
`stash::items(wb, prefix)` now groups the names by item in one pass
and returns each item's text by key, and `keys` lists from the same
pass. Both return at most `MAX_ITEMS` (10,000) items, the first keys
in sorted order, so a file with any number of hidden names can't make
a listing unbounded. A test counts the names each listing looks at.
The xlsx writer drops characters XML 1.0 can't carry: controls other
than tab, line feed and carriage return, and U+FFFE and U+FFFF. A
stash item holding one lost it on save without a warning, and so did
a JSON item, since serde_json leaves U+FFFE and U+FFFF unescaped: a
stored macro parameter changed silently.
`chunk_formulas` now writes each such character, and the marker
itself, as the noncharacter U+FDD0 followed by four hex digits, and
`get` turns them back for `_gc_` items. A marker that isn't followed
by four hex digits naming a character is read as it is. An escape
counts as five units against the 255-unit literal limit and is never
split across literals, and the guard on the stored size allows the
longest item even when every character is escaped. Legacy `_sc_`
items are read unchanged.
Two items under one key, in any case, would leave two hidden names of one
name, of which an xlsx file keeps one, and get would mix their chunks. A
caller's mistake, refused before anything changes. Regression test.
- Workbook::macros is a shared list (Macros, a copy-on-write newtype): a
workbook copy made for a cell edit or an undo snapshot holds the same list,
and the undo budget charges a list once a snapshot owns its own copy.
Before, every mutating command copied every step of every macro, and a
hundred undo entries kept a hundred copies the budget never saw.
- Saving to xlsx drops the last save's items and writes the macros in one
pass each (stash::set_many), instead of a scan of every name per macro.
- A hidden _gc_macro_<x>_<k> name with a key this build did not write is
kept on open and on save, as a visible one is, instead of being dropped
without a warning.
- macros::check is the one check for every path that adds a macro (JSON, a
file, built in code): the model's limits and the xlsx size limit.
Regression tests for each.
stash::keys reported a key that get read as missing, because only a later
chunk of it existed. keys now counts chunk 0 and legacy names only, as get
does. Regression assertions in the hostile-names test.
`_gc_watch_00` parsed as chunk 0, so a hidden one was read as the item's first
chunk and a visible one stopped `_gc_watch_0` from being written. Only the
chunk number as `set` writes it counts now. Regression test.
The check ran once per chunk, each a scan of every defined name: an item of many chunks in a workbook with thousands of names compared every pair. One pass now parses each visible workbook-scope name and refuses when it is a chunk of this key below the chunk count. The behaviour and its test are unchanged.
The item store read, listed and removed every workbook-scope name of the `_gc_<key>_<n>` shape,
visible or not, so saving an item removed a person's own visible name that happened to look like
one. Items are the hidden names the store writes; a legacy `_sc_<key>` name still reads. A visible
`_gc_` name is left alone by every operation, and writing an item that would need that name is
refused before anything changes: a hidden name beside it with the same name is the one an xlsx
file drops, so the item would be lost on save.
GridCraft keeps workbook data in hidden defined names so it travels
inside the xlsx file. The existing items write one name holding one
string literal, which past Excel's 255-character literal and
8,192-character formula limits gives a file Excel does not accept.
cmd/stash.rs stores an item `key` as hidden workbook-scope names
_gc_<key>_0, _gc_<key>_1, ..., each a formula of string literals of at
most 255 characters (UTF-16 units, as Excel counts them) joined with &,
at most 8,192 characters per name. Reading concatenates the chunks in
order and stops at a gap; it also accepts the older single _sc_<key>
name. Names are matched case-insensitively and only at workbook scope.
Keys are limited to letters, digits, _ and ., items to 4,194,304
characters, and junk around or inside the literals, duplicate or
out-of-order chunks, non-JSON and over-deep JSON all read safely.
keys(prefix) lists the stored items that start with a prefix.
Custom views, scripts, the watch list and scenarios keep their current
storage; nothing reads or writes the new names yet.
docs/architecture.md describes the engine building blocks added in this
series: undo groups, the recording buffer, document trust and this
storage.
prxnvt