Several changes have been committed to allow the user to create
in-memory references and write back to disk. Peeling of symbolic
references has been made explicit. Added getter and setter methods for
all attributes on a reference. Added corresponding documentation.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

All the commits have been squashed into a single one before refactoring
the final code, to keep everything tidy.

Individual commit messages are as follows:

Added repository reference looking up functionality placeholder.

Added basic reference database definition and caching infrastructure.

Removed useless constant.

Added GIT_EINVALIDREFNAME error and description. Added missing description for GIT_EBAREINDEX.

Added GIT_EREFCORRUPTED error and description.

Added GIT_ETOONESTEDSYMREF error and description.

Added resolving of direct and symbolic references.

Prepared the packed-refs parsing.

Added parsing of the packed-refs file content.

When no loose reference has been found, the full content of the packed-refs file is parsed. All of the new (i.e. not previously parsed as a loose reference) references are eagerly stored in the cached references storage.

The method packed_reference_file__parse() is in deer need of some refactoring. :-)

Extracted to a method the parsing of the peeled target of a tag.

Extracted to a method the parsing of a standard packed ref.

Fixed leaky removal of the cached references.

Ensured that a previously parsed packed reference isn't returned if a more up-to-date loose reference exists.

Enhanced documentation of git_repository_reference_lookup().

Moved some refs related constants from repository.c to refs.h.

Made parsing of a packed tag reference more robust.

Updated git_repository_reference_lookup() documentation.

Added some references to the test repository.

Added some tests covering tag references looking up.

Added some tests covering symbolic and head references looking up.

Added some tests covering packed references looking up.

Made git_repository_open2() and git_repository_open3() benefit from recently added path prettifying function.

Made git_repository_open() and git_repository_init() benefit from recently added path prettifying function.

Yes, we are breaking the API. Alpha software, deal with it.

We need a way of getting a pointer to each newly added entry to the
index, because manually looking up the entry after creation is
outrageously expensive.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Require <sys/types.h> to find the definition for off64_t.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

In-memory tree objects were not being properly initialized, because the
internal entries vector was created on the 'parse' method.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

 - Secured buffer ahead reading.
 - Guard against potential multiple dot path traversal (cf http://cwe.mitre.org/data/definitions/33.html)

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Lets the user specify the ODB that will be used by the repository
manually.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Proper function is 'git_commit_time_offset'.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Don't need a brand new header for two typedefs when we already have a
types.h header.

Change comment style to ANSI C.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Clean up a provided absolute or relative directory path.

This prettification relies on basic operations such as coalescing multiple forward slashes into a single slash, removing '.' and './' current directory segments, and removing parent directory whenever '..' is encountered. If not empty, the returned path ends with a forward slash.

For instance, this will turn "d1/s1///s2/..//../s3" into "d1/s3/".

This only performs a string based analysis of the path. No checks are done to make sure the path actually makes sense from the file system perspective.

This will allow graceful migration to 64 bit file sizes and timestamps should
git's binary interface be extended to allow this.

Windows uses a 64 bit time_t by default and assigning to unsigned int causes a
64 -> 32 bit truncation warning. This change forces the truncation,
acknowledging the implications detailed in the file comments. Also, blobs are
limited to 32 bit file sizes for the same reason (on all platforms).

Off_t is not cool. It can be 32 or 64 bits depending on the platform,
but on the Index format, it's always 32 bits.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

- remove() would read one-past array bounds.
- resize() would fail if the initial size was 1, because it multiplied by 1.75
  and truncated the resulting value. The buffer would always remain at size 1,
  but elements would repeatedly be appended (via insert()) causing a crash.

Major changes and rationale:
- /WX: absolutely vital when compiling in C-mode as the compiler is
  incredibly lenient on what is allowed to compile. It allows functions to be
  called without prototypes declared, treating them as functions returning int
  taking an unspecified (read: unrestricted) list of arguments, without any
  type checking! It will simply issue a warning, which is easily overlooked.

  A real example: it will allow you to call ceil(1.75) without first including
  <math.h> causing UB, returning bogus results like 1023 on the machine I
  tested on.

- Release build separate from debug.
  Presently release builds don't exist.  Consequently they are completely
  untested. Many bugs may only manifest themselves in release mode. The current
  configuration sets debug-only flags like /RTC1 which are incompatible with
  optimization (/O2).

  In addition, the Windows build of libgit2 has no optimized version. This
  change resolves this.

- Added checksum generation in image headers. This is so debuggers don't
  complain about checksum mismatches and provides a small amount of consistency
  to binaries.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Don't hardcode the '/sbin/ldconfig' path; also, don't run anything if
ldconfig cannot be found (Mac OS X, for instance).

Signed-off-by: Vicent Marti <tanoku@gmail.com>

All the relevant git_object methods have been moved to object.c

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Keep all the repository init code as static.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

It's MurmurHash3 slightly edited to make it
cross-platform. Fast and neat.

Use this for hashing strings on hash tables instead
of a full SHA1 hash. It's very fast and well distributed.

Obviously not crypto-secure.

Signed-off-by: Vicent Marti <tanoku@gmail.com>