got

got is just an implementation of git using go, trying to implement some of the features git supports

Part (1):

• This part is all about blobs, how to hash blobs just like git is doing.

What is the difference btn blobs and files ?

• Blobs are Binary Large Objects which is the content of the file.

• Blob is represented in SHA-1HASH, which are 20 bytes that identify this blob in git world.

• Files are the actuall file with it's own metadata, and this is the difference between files and blobs, if we create a file and move it to another directory, its creation date will remain the same, but blobs doesn't keep these info.

• To use the hashing that git is using :

echo -n <content> | git hash-object --stdin

• To get the Sha1-Hash of a content :

echo -n <content> | shasum -a 1

• So git uses the shasum (sha1-hash) to give you the final hash of the content, but if we used the 2 commands above on the same content string we will get different hashes ?
  • Because git hash-object command uses shasum command with other data :

    shasum "blob <content-size>\o<conent-data>"

  • Example :

      > echo -n 'blob 11\0git with go' | shasum -a 1
      fd790ad99ff75c6c383962e2f0bc1ffeabc22142  -
                  
      > echo -n 'git with go' | shasum -a 1         
      1cd141fb363aca49017c83d35f3609d1819eb3b0  -
                  
      > echo -n 'git with go' | git hash-object --stdin                                                 
      fd790ad99ff75c6c383962e2f0bc1ffeabc22142