When support for sections (and thus hierarchical images) was added to
binman, the decision was made to create a new Section class which could
be used by both Image and an Entry_section class. The decision between
using inheritance and composition was tricky to make, but in the end it
was decided that Image was different enough from Entry that it made sense
to put the implementation of sections in an entirely separate class. It
also has the advantage that core Image code does have to rely on an entry
class in the etype directory.

This work was mostly completed in commit:

   8f1da50ccc "binman: Refactor much of the image code into 'section'

As a result of this, the Section class has its own version of things like
offset and size and these must be kept in sync with the parent
Entry_section class in some cases.

In the last year it has become apparent that the cost of keeping things in
sync is larger than expected, since more and more code wants to access
these properties.

An alternative approach, previously considered and rejected, now seems
better.

Adjust Image to be a subclass of Entry_section. Move the code from Section
(in bsection.py) to Entry_section and delete Section. Update all tests
accordingly.

This requires substantial changes to Image. Overall the changes reduce
code size by about 240 lines. While much of that is just boilerplate from
Section, there are quite a few functions in Entry_section which now do not
need to be overiden from Entry. This suggests the change is beneficial
even without further functionality being added.

A side benefit is that the properties of sections are now consistent with
other entries. This fixes a problem in testListCmd() where some properties
are missing for sections.

Unfortunately this is a very large commit since it is not feasible to do
the migration piecemeal. Given the substantial tests available and the
100% code coverage of binman, we should be able to do this safely.

Signed-off-by: Simon Glass <sjg@chromium.org>

It is useful to be able to summarise all the entries in an image, e.g. to
display this to this user. Add a new ListEntries() method to Entry, and
set up a way to call it through the Image class.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add support for detecting entries that change size after they have already
been packed, and re-running packing when it happens.

This removes the limitation that entry size cannot change after
PackEntries() is called.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present if this function tries to update the contents such that the
size changes, it raises an error. We plan to add the ability to change
the size of entries after packing is completed, since in some cases it is
not possible to determine the size in advance.

An example of this is with a compressed device tree, where the values
of the device tree change in SetCalculatedProperties() or
ProcessEntryContents(). While the device tree itself does not change size,
since placeholders for any new properties have already bee added by
AddMissingProperties(), we cannot predict the size of the device tree
after compression. If a value changes from 0 to 0x1234 (say), then the
compressed device tree may expand.

As a first step towards supporting this, make ProcessContentsUpdate()
return a value indicating whether the content size is OK. For now this is
always True (since otherwise binman raises an error), but later patches
will adjust this.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present this function always sets both the offset and the size of
entries. But in some cases we want to set only one or the other, for
example with the forthcoming ifwi entry, where we only set the offset.
Update the function to handle this.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present binman requires that the Intel descriptor has an explicit
offset. Generally this is 0 since the descriptor is at the start of the
image. Add a default to handle this, so users don't need to specify the
offset.

Signed-off-by: Simon Glass <sjg@chromium.org>

Some functions lack comments in this file. Add comments to cover this
functionality.

Signed-off-by: Simon Glass <sjg@chromium.org>

This comment is out of date as it does not correctly describe the return
value. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>

The method of multiplying a character by a number works well for creating
a repeated string in Python 2. But in Python 3 we need to use bytes()
instead, to avoid unicode problems, since 'bytes' is no-longer just an
alias of 'str'.

Create a function to handle this detail and call it from the relevant
places in binman.

Signed-off-by: Simon Glass <sjg@chromium.org>

Python 3 requires this, and Python 2 allows it. Convert the code over to
ensure compatibility with Python 3.

Signed-off-by: Simon Glass <sjg@chromium.org>