With Zip64 write support enabled by default, it's important that we
only store the extra data when we need to. This commit ensures that
the Zip64 extra data is included for an entry if its size is over
4GB, or if we don't know how big it will be at the point of writing
the local header data.
This commit also removes the need for the Zip64Placeholder extra
data field. Now we just use the Zip64 field itself and ensure it's
filled in correctly.
Previously if RubyZip attempted to create an archive with more than
64K entries, the central directory would truncate the count. `unzip`
and `zipinfo` would fail with an error message such as:
```
error: expected central file header signature not found (file #93272).
(please check that you have transferred or created the zipfile in the
appropriate BINARY mode and that you have compiled UnZip properly)
```
This generated a lot of confusion and a production issue since many
tools fail to decode a RubyZip-created archive if Zip64 is not enabled
for a large number of files. Since Zip64 support is now the norm,
enable this by default.
When loading extra fields from both the central directory and local headers,
unknown fields were not merged correctly. They were being appended, which
means that we end up with the two versions stuck together - in some
cases duplicating the field completely.
This broke all kinds of things (like calculating the size of a local
header) in subtle ways.
This commit fixes this by implementing a new `Unknown` extra field type,
and making sure that when reading local and central extra fields they
are stored and preserved correctly. We cannot assume the unknown fields
use the same data in the local and central headers.
Fixes#505.
This greatly simplifies the creation of `Entry` objects when only a
couple of fields are not set to their defaults, while at the same time
allowing an `Entry` to be fully configured at creation time if
appropriate.
This fundamentally changes the `Entry` API and means that some
convenience methods in `OutputStream` and `File` have needed to be
refactored.
Allow an Entry to specify a compression level and pass this down to the
underlying OutputStream infrastructure. OutputStream has been able to
specify a compression level for a while but this has, up until now, only
ever been set to the default.
This fundamentally changes the API so will need a major version bump.
Robert Haines
Stan Hu
Koichi ITO
Pavel Lobashov
Pavel.Lobashov
Alexander Simonov