[JGIT PATCH 0/3] Introduce AbbreviatedObjectId

I'm using this new type to handle the "index" line of a git patch file, where object ids are generally shorter than 40 characters and thus aren't parsable by ObjectId.

Reading the short id is important because we can validate that a patch applies correctly by computing the SHA-1 of the result and testing it against the abbreviated id read in the "index" line. If the base object SHA-1 matches the abbreviated line then the result of applying the patch must also match; if it doesn't the patch application logic is broken.

Shawn O. Pearce (3):
  Define an abstraction for handling abbreviated SHA-1 strings
  Add ObjectId.startsWith(AbbreviatedObjectId)
  Change AnyObjectId.abbreviate() to return AbbreviatedObjectId

 .../ui/internal/components/RefContentProposal.java |    2 +-
 .../egit/ui/internal/fetch/FetchResultTable.java   |   12 +-
 .../egit/ui/internal/push/PushResultTable.java     |   21 +-
 .../src/org/spearce/jgit/pgm/Branch.java           |    2 +-
 .../src/org/spearce/jgit/pgm/Fetch.java            |    8 +-
 .../src/org/spearce/jgit/pgm/Push.java             |    5 +-
 .../spearce/jgit/lib/AbbreviatedObjectIdTest.java  |  285 ++++++++++++++++++++
 .../org/spearce/jgit/lib/AbbreviatedObjectId.java  |  262 ++++++++++++++++++
 .../src/org/spearce/jgit/lib/AnyObjectId.java      |   39 +++-
 9 files changed, 608 insertions(+), 28 deletions(-)
 create mode 100644 org.spearce.jgit.test/tst/org/spearce/jgit/lib/AbbreviatedObjectIdTest.java
 create mode 100644 org.spearce.jgit/src/org/spearce/jgit/lib/AbbreviatedObjectId.java