To outline what should be done in each command or method of the Repository
class, let's go through the common Git commands and repository methods. Below is a high-level explanation of each method's tasks, step-by-step, which can serve as a "to-do" list for implementation:
- Purpose: Initializes a new Git repository.
- To-Do:
- Create a new
.git
directory. - Create subdirectories like
objects
,refs
,heads
. - Initialize the
HEAD
file pointing torefs/heads/master
. - Create an empty index file (
.git/index
).
- Create a new
- Purpose: Adds a file to the staging area (index).
- To-Do:
- Read the file's content and calculate its hash using SHA-1.
- Store the file content in the
objects
folder (as a blob object). - Update the index file with the file’s path, permissions, and hash.
- Manage file modes (executable, regular files).
- Ensure that the index file is updated with the new entry.
- Purpose: Records changes to the repository.
- To-Do:
- Read the index and gather all staged files.
- Create a tree object based on the file structure.
- Create a commit object with the tree hash, parent commit hash (if any), author information, and commit message.
- Write the commit object to the
objects
folder. - Update the
HEAD
to point to the new commit hash.
- Purpose: Shows the commit history.
- To-Do:
- Read the
HEAD
to get the latest commit. - Recursively walk through the parent commits.
- For each commit, display the author, timestamp, and commit message.
- Read the
- Purpose: Displays the working directory and staging area status.
- To-Do:
- Compare the current working directory with the index to find any changes.
- List files that have been modified, added, or deleted.
- Check for files that are staged for commit.
- Display untracked files that aren’t yet in the index.
- Purpose: Switches to a specific commit, branch, or file.
- To-Do:
- Look up the commit object by hash.
- Extract the tree object associated with the commit.
- Update the working directory to reflect the state of the specified commit.
- Update the
HEAD
to point to the specified commit or branch.
- Purpose: Creates a new branch.
- To-Do:
- Create a new reference under
refs/heads/
that points to the current commit. - Ensure the
HEAD
stays where it is unless explicitly moved (e.g., bycheckout
).
- Create a new reference under
- Purpose: Merges the specified branch into the current branch.
- To-Do:
- Retrieve the latest commit on the current branch and the branch to be merged.
- Find the common ancestor of both branches.
- Merge the changes by applying the differences from the common ancestor.
- Handle conflicts if both branches have modified the same file.
- Create a merge commit.
- Purpose: Tags a commit.
- To-Do:
- Create a tag object that references a specific commit.
- Store the tag information in the
refs/tags/
directory. - Optional: Create an annotated tag with a message, author, and date.
- Purpose: Shows changes between commits, working tree, and index.
- To-Do:
- Compare the index with the current working directory to show unstaged changes.
- Compare the index with the last commit to show staged changes.
- Optionally, compare two commits for historical differences.
- Purpose: Resets the current branch to a specific commit.
- To-Do:
- Update
HEAD
to point to the given commit. - Update the index to match the tree of the specified commit.
- Optionally, update the working directory to match the commit.
- Update
- Purpose: Creates a new commit that undoes the changes introduced by a previous commit.
- To-Do:
- Find the commit object by its hash.
- Apply an inverse patch to undo the changes in that commit.
- Create a new commit with the reverted changes.
- Purpose: Clones a repository from a remote location.
- To-Do:
- Download the remote repository's contents (this can be as simple as copying
.git
contents for local repositories). - Set up the local repository with references to the remote repository.
- Initialize tracking branches.
- Download the remote repository's contents (this can be as simple as copying
- Purpose: Fetches updates from a remote repository.
- To-Do:
- Connect to the remote repository and download the latest objects and references.
- Update the local references (e.g.,
refs/remotes/origin/master
).
- Purpose: Pushes local changes to a remote repository.
- To-Do:
- Authenticate with the remote repository.
- Compare local references with remote ones to see what needs to be pushed.
- Send the commit objects, trees, and blobs that aren’t already on the remote.
- Update the remote references to point to the pushed commits.
- Error Handling: Each method should handle errors (e.g., missing files, invalid paths, permission errors) gracefully.
- File Operations: The
FileAdapter
(or any future file handling module) should be used for all reading and writing operations to keep file operations consistent and modular. - Logging: For debugging and tracking purposes, consider adding logs or print statements to show when significant actions are performed (e.g., file written, index updated, etc.).
- Compression/Decompression: For object storage, use Git's compression mechanism (zlib) when writing objects to the
objects
directory.
This high-level overview should help you define the structure and behavior of each method in the Repository
class. If you'd like further clarification on any specific method, feel free to ask!
+---------------+ | Repository | +---------------+ | - name | | - description | | - commits | | | | +------------+ | | init() | | | add() | | | commit() | | | log() | | | checkout() | | +------------+ +---------------+ | | v +---------------+ | Commit | +---------------+ | - id | | - parent | | - author | | - timestamp | | - message | | | | +------------+ | | Commit() | | | getParent() | | | getAuthor() | | | getTimestamp() | | | getMessage() | | +------------+ +---------------+ | | v +---------------+ | Tree | +---------------+ | - id | | - entries | | | | +------------+ | | Tree() | | | addEntry() | | | getEntries() | | +------------+ +---------------+ | | v +---------------+ | Entry | +---------------+ | - name | | - mode | | - hash | | | | +------------+ | | Entry() | | | getName() | | | getMode() | | | getHash() | | +------------+ +---------------+ | | v +---------------+ | Blob | +---------------+ | - id | | - data | | | | +------------+ | | Blob() | | | getData() | | +------------+ +---------------+ | | v +---------------+ | Index | +---------------+ | - entries | | | | +------------+ | | Index() | | | addEntry() | | | getEntries() | | +------------+ +---------------+ | | v +---------------+ | Workspace | +---------------+ | - files | | | | +------------+ | | Workspace() | | | addFile() | | | getFile() | | +------------+ +---------------+