Acknowledgement

Course taught: CS61B spring 2021 Data structures

Projects/labs/notes

Link: https://sp21.datastructur.es/

Instructor: Josh Hug (the best)

Gitlet

Project2 Gilet is a git-like version control system features all local git key functions.

I put a lot of effort in it and learned a lot through the process so I am kinda pround of it.

Algorithms

Each file in your working directory can be in one of two states: tracked or untracked.

• Tracked files -- that Gitlet knows about it.

  • Files has been added and staged.
  • File is modified if:
    • present in working directory, contents different than in head commit, and not staged.
    • present in working directory, has been staged, but file contents in stage area is different than in working directory. (dirty state)
    • absent in working directory, but in stage added.
    • absent in working directory, present in head commit, but not in stage removed.

• Untracked files

  • Files in current working area, but not in last commit(head) and hasen't yet been staged.

• Objects

  • Stage: represent a staging area, contains HashMap<String filename, String blobId> added ; HashSet<String filename> removed
  • Commit: represent a commit object, contains commitId, it's parents, tracked files, timeStamp, and commit message. |(SHA1)
  • Blob: represent a blob object contains blobId |(SHA1(filename,contents)), filename(join(CWD,filename)), byte [] content

• Merge

How to run

Compile with

  gitlet/*.java

Everything is set! run

  java gitlet.Main [command]

Gitlet features keyfunctions of local Git (make sure init before use other command)

   init
   add [file name] 
   commit [message]
   rm [file name]
   log
   global-log
   status
   find [commit message]
   branch [branch name]
   rm-branch [branch name]
   checkout -- [filename]
   checkout [commit id] -- [file name]
   checkout [branch name]
   reset [commit id]
   merge [branch name]

Persistence

.gitlet
    -- blobs
    -- commits
	-- staging
	-- [stage]
    -- refs
		-- heads -> [master][branch name]
	-- [HEAD]

blobs directory: stores all tracked(committed) file(name:blobId, content:blob.content)

commits directory: stores all commit objects

Staging: stores added file(filename, blobId), removed filename

stage: stage object

heads : stores branches, with branch name and a reference to commit

HEAD: a pointer reference current branch name if points at