Martino FerrariandClaude Opus 4.6
4003084648
Clicking the coloured chip in the signal list opens a GtkColorDialog and the colour it returns overrides that signal's palette entry. Held by name, like every other identity here, and persisted as a session `[[color]]` table. RowSet::signal_color() becomes the one resolver: install() builds the trace through it and all three chip sites read it, because a chip exists to say which trace a row is about and an override is exactly the state in which two routes to a colour would disagree. A grey chip names no trace and so is not clickable, and the way back is `Default colour` in the signal's menu -- a setting with no undo is a trap. The gesture sits on the existing label rather than in a GtkButton: padding on this row is what made the signal list twice as tall once. It claims its sequence so a click on the chip cannot become the start of a row drag. UDPSCOPE_PROBE_COLOR_MS reads the result out of plot::Plot::trace() and out of the chip's own markup, with an override in no palette slot, so neither leg can pass by asking the resolver what it already said. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
53 lines
4.4 KiB
Markdown
53 lines
4.4 KiB
Markdown
# Invariants: the session file, the export and the source chooser
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What a session persists and in what order, when a save is refused, and when an export is collected.
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Part of [CLAUDE.md](../../CLAUDE.md). These are rules that cost a defect to learn; read the ones touching the area you are editing before you edit it.
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- **The session is the layout.** `LayoutState` persists what makes a reopened scope look like the
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one that was closed: the window, the rows and their slot signals, the calibration, **the enabled
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signals**, **the chosen trace colours** (`[[color]]`, `name` + `rgb = "#RRGGBB"` — only the
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*overrides*, so a stream's new signals still take the positional palette and a saved session does
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not freeze a colour that is meant to follow the signal list), **the math channels with their
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graphs** and **the measurements pane**. Signal identity
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is the *name* throughout (a CONFIG renumbers channels), 'enabled' is read off the channels the
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model built -- an enabled signal is exactly one that produced a channel -- and `apply_layout()`
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installs the graphs **before** assigning the rows, since a row may hold a math channel's name and
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that name is only a signal once its graph is in. Two format rules, both learned the hard way:
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write an op or a measure *type* as its index through `math_op_at()`/`measure_type_at()`, never as
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the raw enum value -- those accessors' orders are the dialog's, not the declaration order, so
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writing one and reading the other silently renames operations. And a top-level key written after
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a `[[table]]` belongs to *that table* in TOML: `enabled = [...]` emitted after `[[calibration]]`
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was parsed into the last calibration record and the enable state was lost without a word.
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`mkdirs()` used to create only components with a trailing slash, so `~/.config/udpscope` was never
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made and the *first* save failed silently -- worth knowing when a layout change "does not stick".
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- **The export is collected at click time, not in the file-dialog callback.** The live
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view keeps scrolling while the chooser is up, so a late collection would write a
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window the user never saw. The writer is picked by the chosen path's extension.
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- **The chooser runs before `ScopeModel` exists, and `--server` is what decides.** `Config` carries
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`server_specified`, set only by the `--server` branch, and `main()` asks only when it is false —
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so declining costs no buffer and no socket, and `ScopeModel`, `Acquisition`, `RowSet` and
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`run_ui()` need no notion of "no source yet". It is `--server` alone and not "no arguments":
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`--multicast` still needs a server to fetch CONFIG from. **Every documented probe passes
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`--server`**, which is what makes the feature invisible to the regression net — a probe added
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without it would reach the chooser and hang. `gtk_init()` plus a nested `GMainLoop`, and then
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`run_ui()`'s `GtkApplication` afterwards in the same process, is a verified combination
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(`gtk_init()` is idempotent; running your own loop is the documented GTK4 replacement for the
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removed `gtk_dialog_run()`).
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- **A session file's name cannot say how its source was reached, so the file says it.**
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`<host>_<port>.toml` carries neither the multicast group nor the interface, so a chooser row
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could not reconnect to a multicast source at all. `LayoutState::multicast`/`interface_addr` are
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written in the **top block, before the first `[[table]]`** — a bare key after a table header is
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that table's key in TOML, which is exactly how `enabled` was parsed into the last
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`[[calibration]]` record and lost without a word. A file from an older build has neither key and
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loads as unicast on the default route. The chooser's list filters to sessions that **name at
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least one signal**, because a probe run leaves a file per throwaway port and all of them hold
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`signals = ["", "", "", ""]`; `known_sources()` splits the filename at the **last** `_`, since
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`sanitize()` turns anything unsafe in a host into one.
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- **`save_layout_now()` refuses to write while `signals()` is empty.** A run against a source
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whose streamer was down receives no CONFIG, so every slot name stays empty and the save would
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overwrite a configured session with `signals = ["", ...]`. The chooser then filters that file
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out — a source whose streamer was merely down during one run would silently vanish from the
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only list it can be picked from, for ever. Keeping the old file loses nothing: a run that
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configured nothing had nothing worth persisting.
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