If the user wants to keep a copy for themselves, they should make a copy. It adds unnecessary complexity to make sure the returned entries are valid until the builder is cleared.
Finding a filename in a vector means we need to resort it every time we want to read from it, which includes every time we want to write to it as well, as we want to find duplicate keys. A hash-map fits what we want to do much more accurately, as we do not care about sorting, but just the particular filename. We still keep removed entries around, as the interface let you assume they were going to be around until the treebuilder is cleared or freed, but in this case that involves an append to a vector in the filter case, which can now fail. The only time we care about sorting is when we write out the tree, so let's make that the only time we do any sorting.
Rename git_tree_entry_byoid() to _byid() as per the convention.
This wasn't being tested and since it has a callback, I fixed it even though the return value of this callback is not treated like any of the other callbacks in the API.
When a tool needs to recreate the tree object (for example an interface to another VCS), it needs to use the raw attributes, forgoing any normalization.
Fixed a few header @param and @return typos with the help of -Wdocumentation in Xcode. The following warnings have not been fixed: common.h:213 - Not sure how the documentation format is for '...' notes.h:102 - Correct @param name but empty text notes.h:111 - Correct @param name but empty text pack.h:140 - @return missing text pack.h:148 - @return missing text
This adds an example implementation that emulates git cat-file. It is a convenient and relatively simple example of getting data out of a repository. Implementing this also revealed that there are a number of APIs that are still not using const pointers to objects that really ought to be. The main cause of this is that `git_vector_bsearch` may need to call `git_vector_sort` before doing the search, so a const pointer to the vector is not allowed. However, for tree objects, with a little care, we can ensure that the vector of tree entries is always sorted and allow lookups to take a const pointer. Also, the missing const in commit objects just looks like an oversight.