This commit adds barebones capacity to generate diffs from two trees and
to emit those as git-style diffs (via `Patch.String`), or to enumerate
the files/hunks/lines in the diff to emit the data yourself.
The walk functions have been implemented in the same manner as the Odb
walking methods.
Note that not all of the functionality is implemented for either the
`git_diff_*` nor the `git_patch_*` functions, and there are unexposed
constants which would likely be useful to add.
The library stores error information in thread-local storage, which
means we need to make sure that the Go runtime doesn't switch OS
threads between the time we call a function and th time we attempt to
retrieve the error information.
Provide a manual way of freeing objects, but set finalizers for them
in case the user does not want to worry about memory management, which
would be useful for commits or trees, which sare typically small.
When the objects are freed manually, the finalizer is unset to avoid
double-freeing, mimicking what the go runtime does.
lye
Carlos Martín Nieto
Artiom Di
Vicent Martí
Axel Wagner
Vicent Marti