Since we now always build the library with cdecl calling conventions,
our callbacks should be decorated as such so that users will not be able
to provide callbacks defined with other calling conventions.
The `GIT_CALLBACK` macro will inject the `__cdecl` attribute as
appropriate.
This adds a new function that will allow creation of notes without
necessarily updating a particular ref, the notes tree is obtained
from the git_commit object parameter, a new commit object pointing
to the current tip of the notes tree is optionally returned
via the 'note_commit_out' parameter,
optionally the blob id for the note is returned through
the 'note_blob_out' object.
This updates all the `foreach()` type functions across the library
that take callbacks from the user to have a consistent behavior.
The rules are:
* A callback terminates the loop by returning any non-zero value
* Once the callback returns non-zero, it will not be called again
(i.e. the loop stops all iteration regardless of state)
* If the callback returns non-zero, the parent fn returns GIT_EUSER
* Although the parent returns GIT_EUSER, no error will be set in
the library and `giterr_last()` will return NULL if called.
This commit makes those changes across the library and adds tests
for most of the iteration APIs to make sure that they follow the
above rules.
This commit adds basic git notes support to libgit2, namely:
* git_note_read
* git_note_message
* git_note_oid
* git_note_create
* git_note_remove
In the long run, we probably want to provide some convenience callback
mechanism for merging and moving (filter-branch) notes.
Signed-off-by: schu <schu-github@schulog.org>
