The GIT_EXPORT macro is used to declare a function to be externally
accessible to other libraries.  This commit uses GIT_EXPORT to declare
the git_lasterror() function as externally exported.  I verified with
depends.exe that the function is available to external callers (i.e.
in the exports table of the PE file).

Ok, this is the real deal. Hopefully. Here's how it's going to work:

- One main method, called `git__throw`, that sets the error
	code and error message when an error happens.

	This method must be called in every single place where an error
	code was being returned previously, setting an error message
	instead.

	Example, instead of:

		return GIT_EOBJCORRUPTED;

	Use:

		return git__throw(GIT_EOBJCORRUPTED,
			"The object is missing a finalizing line feed");

	And instead of:

		[...] {
			error = GIT_EOBJCORRUPTED;
			goto cleanup;
		}

	Use:

		[...] {
			error = git__throw(GIT_EOBJCORRUPTED, "What an error!");
			goto cleanup;
		}

	The **only** exception to this are the allocation methods, which
	return NULL on failure but already set the message manually.

		/* only place where an error code can be returned directly,
		   because the error message has already been set by the wrapper */
		if (foo == NULL)
			return GIT_ENOMEM;

- One secondary method, called `git__rethrow`, which can be used to
fine-grain an error message and build an error stack.

	Example, instead of:

		if ((error = foobar(baz)) < GIT_SUCCESS)
			return error;

	You can now do:

		if ((error = foobar(baz)) < GIT_SUCCESS)
			return git__rethrow(error, "Failed to do a major operation");

	The return of the `git_lasterror` method will be a string in the
	shape of:

		"Failed to do a major operation. (Failed to do an internal
		operation)"

	E.g.

		"Failed to open the index. (Not enough permissions to access
		'/path/to/index')."

	NOTE: do not abuse this method. Try to write all `git__throw`
	messages in a descriptive manner, to avoid having to rethrow them to
	clarify their meaning.

	This method should only be used in the places where the original
	error message set by a subroutine is not specific enough.

	It is encouraged to continue using this style as much possible to
	enforce error propagation:

		if ((error = foobar(baz)) < GIT_SUCCESS)
			return error; /* `foobar` has set an error message, and
							 we are just propagating it */

The error handling revamp will take place in two phases:

	- Phase 1: Replace all pieces of code that return direct error codes
	with calls to `git__throw`. This can be done semi-automatically
	using `ack` to locate all the error codes that must be replaced.

	- Phase 2: Add some `git__rethrow` calls in those cases where the
	original error messages are not specific enough.

Phase 1 is the main goal. A minor libgit2 release will be shipped once
Phase 1 is ready, and the work will start on gradually improving the
error handling mechanism by refining specific error messages.

OTHER NOTES:

	- When writing error messages, please refrain from using weasel
	words. They add verbosity to the message without giving any real
	information. (<3 Emeric)

	E.g.

		"The reference file appears to be missing a carriage return"
			Nope.

		"The reference file is missing a carriage return"
			Yes.

	- When calling `git__throw`, please try to use more generic error
	codes so we can eventually reduce the list of error codes to
	something more reasonable. Feel free to add new, more generic error
	codes if these are going to replace several of the old ones.

	E.g.

		return GIT_EREFCORRUPTED;

	Can be turned into:

		return git__throw(GIT_EOBJCORRUPTED,
			"The reference is corrupted");

Fix misspelling of git_index_append2 (was git_index_apppend2).

ref test: update a forgotten repo -> repo2

odb backend_sort_cmp should be static

Fix bug in the way pthead_mutex_t was being destroyed in win32.

Add git attributes settings for *.c and *.h to force line endings to LF.

Win32 critical section objects (CRITICAL_SECTION) are not kernel objects.
Only kernel objects are destroyed by using CloseHandle.  Critical sections
are supposed to be deleted with the DeleteCriticalSection API
(http://msdn.microsoft.com/en-us/library/ms682552(VS.85).aspx).

Fix two warnings from Clang.

Fixes issue #173

Both are about not reading the value stored in a variable.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Commit 34e5d87e left one of these unchanged we're trying
to read from a free'd repository.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Support root commits

Fix tree-entry attribute convertion (fix corrupted trees)

Fix -Wunused-but-set-variable warnings

Fix memory leak in pack_backend__free

Isolate "writing" refs tests in a temporary folder

Change implementation of refs tests that alter the current repository to make them run against a temporary clone of the test repository

Do not check the folder's size to detect new packfiles at runtime. This
doesn't work on Win32.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

A root commit is a commit whose branch (usually what HEAD points to)
doesn't exist (yet). This situation can happen when the commit is the
first after 1) a repository is initialized or 2) a orphan checkout has
been performed.

Take this opportunity to remove the symbolic link check, as
git_reference_resolve works on OID refs as well.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Typical use is git_reference_resolve(&ref, ref). Currently, if there is
an error, ref will point to NULL, causing the user to lose that
reference.

Always update resolved_ref instead of just on finding an OID ref,
storing the last valid reference in it.

This change helps simplify the code for allowing root commits.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Magic constant replaced by direct to-string covertion because of:
1) with value length 6 (040000 - subtree) final tree will be corrupted;
2) for wrong values length <6 final tree will be corrupted too.

As of gcc 4.6 -Wall includes -Wunused-but-set-variable. Use GIT_UNUSED
or remove actually unused variables to prevent those warnings.

index.h: Add IDXENTRY flags needed for index operations

Fix memory leaks in the tests

refs: Allow MERGE_HEAD in normalize_name()

Removed the optional `replace` argument, we now have 4 add methods:

	`git_index_add`: add or update from path
	`git_index_add2`: add or update from struct
	`git_index_append`: add without replacing from path
	`git_index_append2`: add without replacing from struct

Yes, this breaks the bindings.

index: Allow user to toggle whether to replace an index entry

Fix going into infinite loop in read_header_loose()

read_header_loose causes infinite loop on this file:
$ cat ../libcppgit/bin/sample-repo/test_mailbox/.git/objects/8f/e274605cbc740a2a957f44b2722a8a73915a09 | base64
eAErKUpNVTAzYzA0MDAzMVHISUxKzSlmWLgkuyN5+rxr6juMPR2EmN8s7Vl9D6oiN7UkkcHJdLbl
7Z3N/oxfE0W8wrSbuFRkAwDFfBn1