Device/Storage/Root

Context

When a Storage device's mount point or drive letter changes (e.g. /mnt/drive1 → /mnt/drive01, or F:\ → G:\), all child Catalog sourcePath values and every indexed file/folder path become stale. The current fallback is a full re-scan via updateDeviceHierarchy(), which reads every file from disk and fails when the device is offline.

Goal: a fast, disk-free alternative that performs a prefix-replace pass on the database (and .idx files in Memory mode), without requiring the device to be mounted.

Trigger

In saveDeviceForm() (~line 617 of mainwindow_tab_device_pr.cpp), inside the existing block:

if (activeDevice->type != "Catalog" && activeDevice->path != previousPath)

When activeDevice->type == "Storage", instead of immediately calling updateDeviceHierarchy(), branch to the new flow described below.

UX — integration into the existing progress panel

No separate dialog. The existing Devices progress panel (setCatalogUpdateUIState) is reused. The choice is presented as a QMessageBox::question before the operation starts, then the chosen operation runs inside the same update-state frame (buttons disabled, stop enabled, wait cursor).

Storage path changed
Old path: /mnt/drive1
New path: /mnt/drive01

How should the catalog indexes be updated?

[ Update path prefix ]   [ Full re-scan ]   [ Skip ]

Choice	Behaviour
Update path prefix	New `"replaceRoot"` operation (see below)
Full re-scan	Existing `updateDeviceHierarchy(..., "update")` unchanged
Skip	`saveDeviceForm()` continues; indexes remain stale

Scope: what changes

Only direct Catalog-type children of the changed Storage device. (Storage cannot contain Storage — no recursion needed.)

Table	Column(s)	Change
`catalog`	`catalog_source_path`	Prefix replace: `oldRoot` → `newRoot`
`file`	`file_full_path`, `file_folder_path`	Prefix replace for all rows in affected catalogs
`folder`	`folder_path`	Prefix replace for all rows in affected catalogs
`storage`	`storage_path`	Set to `newRoot` (currently skipped by `saveDeviceForm`)

catalog_file_path is not touched — the collection location is independent of the device mount point.

Memory mode handling

saveCatalogToFile() already serialises the in-memory SQLite tables back to .idx / .folders.idx. The sequence for each affected catalog in Memory mode:

If not yet loaded (dateLoaded < dateUpdated): call catalog->loadCatalogFileListToTable() and catalog->loadFoldersToTable()
Run the SQL prefix-replace UPDATEs on the in-memory database
Update catalog->sourcePath on the C++ object
Call catalog->saveCatalogToFile("Memory", collectionFolder) — rewrites both .idx (with the updated <catalogSourcePath> header and corrected file_full_path rows) and .folders.idx

In File/Hosted mode, steps 1 and 4 are skipped — the SQL UPDATE is sufficient.

New core method

Location: core/device.h / core/device.cpp

struct StorageRootReplaceResult {
    int catalogsUpdated;
    int filesUpdated;
    int foldersUpdated;
};

StorageRootReplaceResult Device::replaceStorageRootInIndexes(
    const QString& oldRoot,
    const QString& newRoot,
    const QString& connectionName,
    const QString& databaseMode,
    const QString& collectionFolder);

Implementation steps:

Walk subDevices to collect all Catalog-type children
For each catalog: load if needed (Memory mode), run SQL UPDATEs, save back to file (Memory mode)
Update storage.storage_path
Return counts

SQL pattern (parameterized, applied per catalog):

UPDATE file
SET file_full_path    = :newRoot || SUBSTR(file_full_path,    LENGTH(:oldRoot)+1),
    file_folder_path  = :newRoot || SUBSTR(file_folder_path,  LENGTH(:oldRoot)+1)
WHERE file_catalog_id = :catalogId
  AND file_full_path LIKE :oldRootPattern;

UPDATE folder
SET folder_path       = :newRoot || SUBSTR(folder_path, LENGTH(:oldRoot)+1)
WHERE folder_catalog_id = :catalogId
  AND folder_path LIKE :oldRootPattern;

UPDATE catalog
SET catalog_source_path = :newRoot || SUBSTR(catalog_source_path, LENGTH(:oldRoot)+1)
WHERE catalog_id = :catalogId
  AND catalog_source_path LIKE :oldRootPattern;

Where :oldRootPattern = oldRoot + "%".

New operation type in `DeviceUpdateManager`

Add "replaceRoot" as a valid m_updateType. The manager:

Calls rootDevice->replaceStorageRootInIndexes(...) (synchronous — fast, no disk reads except Memory mode .idx writes)
Emits operationStarted / operationFinished / operationError as usual
Reports the result via statusBarLabel: "N catalogs updated — X files, Y folders"

Edge cases

Case	Handling
`oldRoot` not a prefix of a catalog's `catalog_source_path`	Skip that catalog silently
Memory mode `.idx` file not found on disk	Log warning, skip catalog, count as failed
`oldRoot == newRoot`	Blocked upstream — `saveDeviceForm` already checks `path != previousPath`
Windows path separators	Normalize both paths with `QDir::fromNativeSeparators()` before the replace; re-apply `QDir::toNativeSeparators()` when writing back

Out of scope / deferred

Undo — user can re-save the device with the old root and run the prefix replace again
Partial path rename (only a subfolder renamed, not the root) — full root replacement only
.idx file patching for hosted mode — hosted mode uses direct SQLite; no .idx files

Context​

Trigger​

UX — integration into the existing progress panel​

Scope: what changes​

Memory mode handling​

New core method​

New operation type in DeviceUpdateManager​

Edge cases​

Out of scope / deferred​