Previous logic caused garbage collection to kick in, if the init() was
called on empty storage. This has effect of erasing areas twice, if both
areas were empty.
Re-write logic so that we erase areas only on garbage_collect() or reset().
The init() logic already chooses the active area, so no need to touch,
until keys are modified.
Removed also the is_erase_unit_erased() as this is working only on
FLASH devices, and TDBStore should be refactored to work on all storages.
Change the "reserved data" logic so that every time we erase and area,
the content of reserved data is then immediately copied to newly erased
area. This keeps two copies of the data.
When data is requested, return only if checksum is matching.
When data is written, only allow if BOTH checksums are incorrect, meaning
that areas are either corrupted or erased.
Only exception is TDBStore::reset() which erases all keys and reserved data.
Removed all logic that tried to detect, if reserved are was erased or
corrupted. Rely entirely on checksum.
Add moduletest for reserved data.
In case our are contains data from previous reset() or reset_area(),
we might end up in the situation where free space contains valid
key headers, but we have not erased that area yet. This can cause
failures if the deinit() and init() because new scan of that area
would continue as long as keys are found. This causes keys on the
not-yet-erased area to be included in the new instance of TDBStore.
To prevent this failure, check after each key-write that our free
space does not contain valid key headers. Also make sure that we
erase one program unit sector over the master record. If we erased
just the master record,first key might is still there, causing next
init() to find it. Extend erase area by one program unit, so that
build_ram_table() won't find any keys.
Return value was ignored, and TDBStore:init() ended up in a
MBED_ERROR() phase after that.
TDBStore API was limited to allow returning of only two separate
errors, which may end up hiding the actual return value. Change
the documentation slightly to allow returning of original error
code from the underlying block device.
Fixes#11591
Implement the following:
KVStore base class
TDBStore class
FileSystemStore class
SecureStore class
Global APIs
Configuration framework
Design documentation
Seppo Takalo
Amanda Butler
Yossi Levy
David Saada