This makes a lot more sense; we can parse a firmware and export the same XML
we would use in a .builder.xml file. This allows us to two two things:
* Check we can round trip from XML -> binary -> XML
* Using a .builder.xml file we can check ->write() is endian safe
The idea here is to return the size of the firmware, including the header,
footer or other encapsulation. It would be expected that this value would
include the alignment if provided.
This allows us to 'nest' firmware formats, and removes a ton of duplication.
The aim here is to deprecate FuFirmwareImage -- it's almost always acting
as a 'child' FuFirmware instance, and even copies most of the vfuncs to allow
custom types. If I'm struggling to work out what should be a FuFirmware and
what should be a FuFirmwareImage then a plugin author has no hope.
For simple payloads we were adding bytes into an image and then the image into
a firmware. This gets really messy when most plugins are treating the FuFirmware
*as* the binary firmware file.
The GBytes saved in the FuFirmware would be considered the payload with the
aim of not using FuFirmwareImage in the single-image case.
At the moment there are commands to convert one file format to another, but not
to 'merge' or alter them. Some firmware files are containers which can store
multiple images, each with optional id, idx and addresses.
This would allow us to, for instance, create a DfuSe file with two different
raw files that are flashed to different addresses on the SPI flash. It would
also allow us to create very small complicated container formats for fuzzing.
This can be used by writing a `firmware.builder.xml` file like:
<?xml version="1.0" encoding="UTF-8"?>
<firmware gtype="FuBcm57xxFirmware">
<version>1.2.3</version>
<image>
<version>4.5.6</version>
<id>header</id>
<idx>456</idx>
<addr>0x456</addr>
<filename>header.bin</filename>
</image>
<image>
<version>7.8.9</version>
<id>payload</id>
<idx>789</idx>
<addr>0x789</addr>
<data>aGVsbG8=</data>
</image>
</firmware>
...and then using something like:
# fwupdtool firmware-convert firmware.builder.xml firmware.dfu builder dfu
The function fu_firmware_add_image() has the comment text 'If an image with the
same ID is present it is replaced' which has not been true for some time.
This was removed, as the common case of adding two images with no ID would only
leave one. However, some plugins do actually want to dedupe on the ID or IDX,
so provide a flag they can set which enables this functionality without
introducing regressions into other plugins.
